Science.gov

Sample records for life history decisions

  1. Agency and Female Teachers' Career Decisions: A Life History Study of 40 Women

    ERIC Educational Resources Information Center

    Smith, Joan

    2011-01-01

    This article reports on some of the findings of a wider, life history study on the factors affecting the career decisions of 40 female secondary school teachers in England. By using life history interviews, it was possible to gain rich and nuanced insights into the complexity of factors influencing women's career decisions. While acknowledging the…

  2. Asymmetric life-history decision-making in butterfly larvae

    PubMed Central

    Aalberg Haugen, Inger M.; Dahlerus, Josefin; Gotthard, Karl; Wiklund, Christer

    2010-01-01

    In temperate environments, insects appearing in several generations in the growth season typically have to decide during the larval period whether to develop into adulthood, or to postpone adult emergence until next season by entering a species-specific diapause stage. This decision is typically guided by environmental cues experienced during development. An early decision makes it possible to adjust growth rate, which would allow the growing larva to respond to time stress involved in direct development, whereas a last-minute decision would instead allow the larva to use up-to-date information about which developmental pathway is the most favourable under the current circumstances. We study the timing of the larval pathway decision-making between entering pupal winter diapause and direct development in three distantly related butterflies (Pieris napi, Araschnia levana and Pararge aegeria). We pinpoint the timing of the larval diapause decision by transferring larvae from first to last instars from long daylength (inducing direct development) to short daylength conditions (inducing diapause), and vice versa. Results show that the pathway decision is typically made in the late instars in all three species, and that the ability to switch developmental pathway late in juvenile life is conditional; larvae more freely switched from diapause to direct development than in the opposite direction. We contend that this asymmetry is influenced by the additional physiological preparations needed to survive the long and cold winter period, and that the reluctance to make a late decision to enter diapause has the potential to be a general trait among temperate insects. PMID:20953962

  3. Manipulation of life-history decisions using leptin in a wild passerine.

    PubMed

    te Marvelde, Luc; Visser, Marcel E

    2012-01-01

    Seasonal timing of reproduction and the number of clutches produced per season are two key avian life-history traits with major fitness consequences. Female condition may play an important role in these decisions. In mammals, body condition and leptin levels are correlated. In birds, the role of leptin remains unclear. We did two experiments where we implanted female great tits with a pellet releasing leptin evenly for 14 days, to manipulate their perceived body condition, or a placebo pellet. In the first experiment where females were implanted when feeding their first brood offspring we found, surprisingly, that placebo treated females were more likely to initiate a second brood compared to leptin treated females. Only one second brood fledged two chicks while five were deserted late in the incubation stage or when the first egg hatched. No difference was found in female or male return rate or in recruitment rate of fledglings of the first brood, possibly due to the desertion of the second broods. In our study population, where there is selection for early egg laying, earlier timing of reproduction might be hampered by food availability and thus nutritional state of the female before egg laying. We therefore implanted similar leptin pellets three weeks before the expected start of egg laying in an attempt to manipulate the laying dates of first clutches. However, leptin treated females did not initiate egg laying earlier compared to placebo treated females, suggesting that other variables than the perceived body condition play a major role in the timing of reproduction. Also, leptin treatment did not affect body mass, basal metabolic rate or feeding rates in captive females. Manipulating life history decisions using experimental protocols which do not alter individuals' energy balance are crucial in understanding the trade-off between costs and benefits of life history decisions.

  4. Effects of nocturnal illumination on life-history decisions and fitness in two wild songbird species.

    PubMed

    de Jong, Maaike; Ouyang, Jenny Q; Da Silva, Arnaud; van Grunsven, Roy H A; Kempenaers, Bart; Visser, Marcel E; Spoelstra, Kamiel

    2015-05-05

    The effects of artificial night lighting on animal behaviour and fitness are largely unknown. Most studies report short-term consequences in locations that are also exposed to other anthropogenic disturbance. We know little about how the effects of nocturnal illumination vary with different light colour compositions. This is increasingly relevant as the use of LED lights becomes more common, and LED light colour composition can be easily adjusted. We experimentally illuminated previously dark natural habitat with white, green and red light, and measured the effects on life-history decisions and fitness in two free-living songbird species, the great tit (Parus major) and pied flycatcher (Ficedula hypoleuca) in two consecutive years. In 2013, but not in 2014, we found an effect of light treatment on lay date, and of the interaction of treatment and distance to the nearest lamp post on chick mass in great tits but not in pied flycatchers. We did not find an effect in either species of light treatment on breeding densities, clutch size, probability of brood failure, number of fledglings and adult survival. The finding that light colour may have differential effects opens up the possibility to mitigate negative ecological effects of nocturnal illumination by using different light spectra. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  5. Effects of nocturnal illumination on life-history decisions and fitness in two wild songbird species

    PubMed Central

    de Jong, Maaike; Ouyang, Jenny Q.; Da Silva, Arnaud; van Grunsven, Roy H. A.; Kempenaers, Bart; Visser, Marcel E.; Spoelstra, Kamiel

    2015-01-01

    The effects of artificial night lighting on animal behaviour and fitness are largely unknown. Most studies report short-term consequences in locations that are also exposed to other anthropogenic disturbance. We know little about how the effects of nocturnal illumination vary with different light colour compositions. This is increasingly relevant as the use of LED lights becomes more common, and LED light colour composition can be easily adjusted. We experimentally illuminated previously dark natural habitat with white, green and red light, and measured the effects on life-history decisions and fitness in two free-living songbird species, the great tit (Parus major) and pied flycatcher (Ficedula hypoleuca) in two consecutive years. In 2013, but not in 2014, we found an effect of light treatment on lay date, and of the interaction of treatment and distance to the nearest lamp post on chick mass in great tits but not in pied flycatchers. We did not find an effect in either species of light treatment on breeding densities, clutch size, probability of brood failure, number of fledglings and adult survival. The finding that light colour may have differential effects opens up the possibility to mitigate negative ecological effects of nocturnal illumination by using different light spectra. PMID:25780240

  6. Does prolactin mediate parental and life-history decisions in response to environmental conditions in birds? A review.

    PubMed

    Angelier, Frédéric; Wingfield, John C; Tartu, Sabrina; Chastel, Olivier

    2016-01-01

    This article is part of a Special Issue "Parental Care". In vertebrates, adjustments of physiology and behavior to environmental changes are often mediated by central physiological mechanisms, and more specifically by hormonal mechanisms. As a consequence, these mechanisms are thought to orchestrate life-history decisions in wild vertebrates. For instance, investigating the hormonal regulation of parental behavior is relevant to evaluate how parents modulate their effort according to specific environmental conditions. Surprisingly and despite being classically known as the 'parental hormone', prolactin has been overlooked in birds relative to this context. Our aim is to review evidence that changes in prolactin levels can mediate, at least to some extent, the response of breeding birds to environmental conditions. To do so, we first examine current evidence and limits for the role of prolactin in mediating parental behavior in birds. Second, we emphasize the influence of environmental conditions and stressors on circulating prolactin levels. In addition, we review to what extent prolactin levels are a reliable predictor of breeding success in wild birds. By linking environmental conditions, prolactin regulation, parental behavior, and breeding success, we highlight the potential role of this hormone in mediating parental decisions in birds. Finally, we also review the potential role of prolactin in mediating other life history decisions such as clutch size, re-nesting, and the timing of molt. By evaluating the influence of stressors on circulating prolactin levels during these other life-history decisions, we also raise new hypotheses regarding the potential of the prolactin stress response to regulate the orchestration of the annual cycle when environmental changes occur. To sum up, we show in this review that prolactin regulation has a strong potential to allow ecological physiologists to better understand how individuals adjust their life-history decisions

  7. Facultative anadromy in salmonids: linking habitat, individual life history decisions, and population-level consequences

    Treesearch

    Steven F. Railsback; Bret C. Harvey; Jason L. White

    2014-01-01

    Modeling and management of facultative anadromous salmonids is complicated by their ability to select anadromous or resident life histories. Conventional theory for this behavior assumes individuals select the strategy offering highest expected reproductive success but does not predict how population-level consequences such as a stream’s smolt production emerge from...

  8. Life-history data.

    PubMed

    Vanhoutte, Bram; Nazroo, James

    2016-07-15

    Life-history data are quantitative, retrospective and autobiographical data collected through event-history calendars. By mimicking the structure of our memories, these instruments can gather reliable information on different dimensions of the lifecourse. Life-history data enable the duration, timing and ordering of events to be brought to the foreground of analysis. Extending the scope of lifecourse research, life-history data make it possible to examine the long-term effects of past policies with more precision and detail.

  9. Early stress, parental motivation, and reproductive decision-making: applications of life history theory to parental behavior.

    PubMed

    Cabeza de Baca, Tomás; Ellis, Bruce J

    2017-06-01

    This review focuses on the impact of parental behavior on child development, as interpreted from an evolutionary-developmental perspective. We employ psychosocial acceleration theory to reinterpret the effects of variation in parental investment and involvement on child development, arguing that these effects have been structured by natural selection to match the developing child to current and expected future environments. Over time, an individual's development, physiology, and behavior are organized in a coordinated manner (as instantiated in 'life history strategies') that facilitates survival and reproductive success under different conditions. We review evidence to suggest that parental behavior (1) is strategic and contingent on environmental opportunities and constraints and (2) influences child life history strategies across behavioral, cognitive, and physiological domains. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Life History and Identity

    ERIC Educational Resources Information Center

    Tierney, William G.

    2013-01-01

    This article uses the life history method to chronicle the challenges of a low-income, first-generation student en route to college. The paper addresses three questions: how Manuel navigates college and related topics such as roommates, family, and money; how he creates social networks; and how he works with adults such as teachers and…

  11. Stress and life history.

    PubMed

    Monaghan, Pat; Spencer, Karen A

    2014-05-19

    In his book on behavioural endocrinology, Randy Nelson describes 'stress' as a 'notoriously ethereal concept'. Yet, despite this lack of clarity, studies of the consequences of stress across different time scales, life history stages, taxa and levels of biological enquiry form a large part of modern biology and biomedicine. Organisms need to recognise and respond to environmental challenges. Being able to do so appropriately, and with minimal costs, is an important physiological attribute, with great adaptive value. The costs and benefits of different mechanisms that enable organisms to cope with unpredictable environmental changes can be manifest to different degrees at different life stages. Accordingly, the level of stress experienced in the environment can act as a strong selective pressure that drives the evolution of life histories.

  12. Zebra mussel life history

    SciTech Connect

    Ackerman, J.D.

    1995-06-01

    The success of introduced zebra mussels (Dreissena polymorpha (Pallas) and Dreissena bugensis Andrusova) can be related in large parttot a life history that is unlike that of the indigenous freshwater fauna and yet is conserved with marine bivalves. Following external fertilization and embryological development, there is a brief trochophore stage. With the development of a velum and the secretion of a D-shaped larval shell, the larva becomes a D-shaped veliger, which is the first recognizable planktonic larva. Later, the secretion of a second larval shell leads to the last obligate free-swimming veliger stage known as the veliconcha. The last larval stage known as the pediveliger, however, can both swim using its velum or crawl using its fully-functional foot. Pediveligers actively select substrates on which they {open_quotes}settle{close_quotes} by secreting byssal threads and undergo metamorphosis to become plantigrade mussels. The secretion of the adult shell and concomitant changes in growth axis leads to the heteromyariant or mussel-like shape, which is convergent with marine mussels. Like a number of other bivalves, zebra mussels produce byssal threads as adults, but these attachments may be broken enabling their translocation to new areas. The recognition and examination of these life history traits will lead to a better understanding of zebra mussel biology.

  13. Experience and Life History. Roskilde University Life History Project Paper.

    ERIC Educational Resources Information Center

    Salling Olesen, Henning

    The Life History Project at Denmark's Roskilde University is a 5-year research project that was initiated in 1998 to examine learning and participation in adult and continuing education from a life history perspective. The project was designed to build on a broad range of qualitative interview studies and case studies into learning processes. The…

  14. Life History Antecedents of Vocational Indecision.

    ERIC Educational Resources Information Center

    Iaffaldano, Michelle; And Others

    1985-01-01

    Assessed the validity of using systematic life history information to predict three vocational decision-making criteria in 200 college students: vocational decidedness and its two components, vocational identity and vocational maturity. Significant typologies were identified, however, results indicated that the overall construct of vocational…

  15. Life History Antecedents of Vocational Indecision.

    ERIC Educational Resources Information Center

    Iaffaldano, Michelle; And Others

    1985-01-01

    Assessed the validity of using systematic life history information to predict three vocational decision-making criteria in 200 college students: vocational decidedness and its two components, vocational identity and vocational maturity. Significant typologies were identified, however, results indicated that the overall construct of vocational…

  16. Life and Death Decision Analysis.

    DTIC Science & Technology

    1979-12-01

    LIFE SMOKING: CANCER, EMPHYSEMA, SHORTENED LIFE BATHING: FALLING, ELECTROCUTION CONTRACEPTION: DEATH , ILLNESS PREGNANCY: DEATH , ILLNESS ABORTION ...economic effect is the one with the highest probability of causing my death . -13- EXPECTED NET SYSTEM DESIGN BENEFIT TO ME DEATH DEATH (r A(excluding death ...0-AO81 424 STANFORD UNIV CALIF DEPT OF ENGtNEERING-ECONOM!C SYSTEMS F/6 12/1 LIFE ANDI DEATH DECISION ANALYSIS.CU) DEC 79 R A HOWARD N0OOIN-79-C-0036

  17. Tradeoffs in bacteriophage life histories.

    PubMed

    Keen, Eric C

    2014-01-01

    Viruses are the most abundant biological entities on the planet, yet most classical principles of evolutionary biology and ecology were not developed with viruses in mind. Here, the concept of biological tradeoffs, a fundamental tenet of life history theory, is examined in the context of bacteriophage biology. Specifically, several important parameters of phage life histories-replication, persistence, host range, and adsorption-are evaluated for tradeoffs. Available data indicate that replication rate is strongly negatively correlated with both persistence and host range, suggesting that the well-documented tradeoff in macroorganisms between offspring production and offspring quality also applies to phages. The biological tradeoffs that appear to characterize viruses' life histories have potential importance for viral evolution, ecology, and pathogenesis.

  18. Life history tradeoffs in cancer evolution

    PubMed Central

    Boddy, Amy M.; Gatenby, Robert A.; Brown, Joel S.; Maley, Carlo C.

    2014-01-01

    Somatic evolution during cancer progression and therapy results in tumor cells that exhibit a wide range of phenotypes including rapid proliferation and quiescence. Evolutionary life history theory may help us understand the diversity of these phenotypes. Fast life history organisms reproduce rapidly while those with slow life histories show less fecundity and invest more resources in survival. Life history theory also provides an evolutionary framework for phenotypic plasticity with potential implications for understanding ‘cancer stem cells’. Life history theory suggests that different therapy dosing schedules could select for fast or slow life history cell phenotypes, with important clinical consequences. PMID:24213474

  19. History matching through dynamic decision-making

    PubMed Central

    Maschio, Célio; Santos, Antonio Alberto; Schiozer, Denis; Rocha, Anderson

    2017-01-01

    History matching is the process of modifying the uncertain attributes of a reservoir model to reproduce the real reservoir performance. It is a classical reservoir engineering problem and plays an important role in reservoir management since the resulting models are used to support decisions in other tasks such as economic analysis and production strategy. This work introduces a dynamic decision-making optimization framework for history matching problems in which new models are generated based on, and guided by, the dynamic analysis of the data of available solutions. The optimization framework follows a ‘learning-from-data’ approach, and includes two optimizer components that use machine learning techniques, such as unsupervised learning and statistical analysis, to uncover patterns of input attributes that lead to good output responses. These patterns are used to support the decision-making process while generating new, and better, history matched solutions. The proposed framework is applied to a benchmark model (UNISIM-I-H) based on the Namorado field in Brazil. Results show the potential the dynamic decision-making optimization framework has for improving the quality of history matching solutions using a substantial smaller number of simulations when compared with a previous work on the same benchmark. PMID:28582413

  20. Bringing Life to Research: Life History Research and ESL.

    ERIC Educational Resources Information Center

    Kouritzin, Sandra G.

    2000-01-01

    Defines what is meant by life history research methodology and examines how it might benefit research in Teaching English as a Second Language (TESL). Looking at the benefits of life history research, explores how life histories in other fields and in previous research have shifted focus form the extraordinary to the mundane and from the universal…

  1. Diffusion Decision Model: Current Issues and History

    PubMed Central

    Ratcliff, Roger; Smith, Philip L.; Brown, Scott D.; McKoon, Gail

    2016-01-01

    There is growing interest in diffusion models to represent the cognitive and neural processes of speeded decision making. Sequential-sampling models like the diffusion model have a long history in psychology. They view decision making as a process of noisy accumulation of evidence from a stimulus. The standard model assumes that evidence accumulates at a constant rate during the second or two it takes to make a decision. This process can be linked to the behaviors of populations of neurons and to theories of optimality. Diffusion models have been used successfully in a range of cognitive tasks and as psychometric tools in clinical research to examine individual differences. In this article, we relate the models to both earlier and more recent research in psychology. PMID:26952739

  2. Adaptable history biases in human perceptual decisions

    PubMed Central

    Abrahamyan, Arman; Silva, Laura Luz; Dakin, Steven C.; Gardner, Justin L.

    2016-01-01

    When making choices under conditions of perceptual uncertainty, past experience can play a vital role. However, it can also lead to biases that worsen decisions. Consistent with previous observations, we found that human choices are influenced by the success or failure of past choices even in a standard two-alternative detection task, where choice history is irrelevant. The typical bias was one that made the subject switch choices after a failure. These choice history biases led to poorer performance and were similar for observers in different countries. They were well captured by a simple logistic regression model that had been previously applied to describe psychophysical performance in mice. Such irrational biases seem at odds with the principles of reinforcement learning, which would predict exquisite adaptability to choice history. We therefore asked whether subjects could adapt their irrational biases following changes in trial order statistics. Adaptability was strong in the direction that confirmed a subject’s default biases, but weaker in the opposite direction, so that existing biases could not be eradicated. We conclude that humans can adapt choice history biases, but cannot easily overcome existing biases even if irrational in the current context: adaptation is more sensitive to confirmatory than contradictory statistics. PMID:27330086

  3. Hominin life history: reconstruction and evolution.

    PubMed

    Robson, Shannen L; Wood, Bernard

    2008-04-01

    In this review we attempt to reconstruct the evolutionary history of hominin life history from extant and fossil evidence. We utilize demographic life history theory and distinguish life history variables, traits such as weaning, age at sexual maturity, and life span, from life history-related variables such as body mass, brain growth, and dental development. The latter are either linked with, or can be used to make inferences about, life history, thus providing an opportunity for estimating life history parameters in fossil taxa. We compare the life history variables of modern great apes and identify traits that are likely to be shared by the last common ancestor of Pan-Homo and those likely to be derived in hominins. All great apes exhibit slow life histories and we infer this to be true of the last common ancestor of Pan-Homo and the stem hominin. Modern human life histories are even slower, exhibiting distinctively long post-menopausal life spans and later ages at maturity, pointing to a reduction in adult mortality since the Pan-Homo split. We suggest that lower adult mortality, distinctively short interbirth intervals, and early weaning characteristic of modern humans are derived features resulting from cooperative breeding. We evaluate the fidelity of three life history-related variables, body mass, brain growth and dental development, with the life history parameters of living great apes. We found that body mass is the best predictor of great ape life history events. Brain growth trajectories and dental development and eruption are weakly related proxies and inferences from them should be made with caution. We evaluate the evidence of life history-related variables available for extinct species and find that prior to the transitional hominins there is no evidence of any hominin taxon possessing a body size, brain size or aspects of dental development much different from what we assume to be the primitive life history pattern for the Pan-Homo clade. Data for

  4. Hominin life history: reconstruction and evolution

    PubMed Central

    Robson, Shannen L; Wood, Bernard

    2008-01-01

    In this review we attempt to reconstruct the evolutionary history of hominin life history from extant and fossil evidence. We utilize demographic life history theory and distinguish life history variables, traits such as weaning, age at sexual maturity, and life span, from life history-related variables such as body mass, brain growth, and dental development. The latter are either linked with, or can be used to make inferences about, life history, thus providing an opportunity for estimating life history parameters in fossil taxa. We compare the life history variables of modern great apes and identify traits that are likely to be shared by the last common ancestor of Pan-Homo and those likely to be derived in hominins. All great apes exhibit slow life histories and we infer this to be true of the last common ancestor of Pan-Homo and the stem hominin. Modern human life histories are even slower, exhibiting distinctively long post-menopausal life spans and later ages at maturity, pointing to a reduction in adult mortality since the Pan-Homo split. We suggest that lower adult mortality, distinctively short interbirth intervals, and early weaning characteristic of modern humans are derived features resulting from cooperative breeding. We evaluate the fidelity of three life history-related variables, body mass, brain growth and dental development, with the life history parameters of living great apes. We found that body mass is the best predictor of great ape life history events. Brain growth trajectories and dental development and eruption are weakly related proxies and inferences from them should be made with caution. We evaluate the evidence of life history-related variables available for extinct species and find that prior to the transitional hominins there is no evidence of any hominin taxon possessing a body size, brain size or aspects of dental development much different from what we assume to be the primitive life history pattern for the Pan-Homo clade. Data for

  5. End-of-life decisions: Christian perspectives.

    PubMed

    Stempsey, William E

    1997-12-01

    While legal rights to make medical treatment decisions at the end of one's life have been recognized by the courts, particular religious traditions put axiological and metaphysical meat on the bare bones of legal rights. Mere legal rights do not capture the full reality, meaning and importance of death. End-of-life decisions reflect not only the meaning we find in dying, but also the meaning we have found in living. The Christian religions bring particular understandings of the vision of life as a gift from God, human responsibility for stewardship of that life, the wholeness of the person, and the importance of the dying process in preparing spiritually for life beyond earthly life, to bear on end-of-life decisions.

  6. Temperature, activity, and lizard life histories

    SciTech Connect

    Adolph, S.C.; Porter, W.P. )

    1993-08-01

    Lizard life-history characteristics vary widely among species and populations. Most authors seek adaptive or phylogenetic explanations for life-history patterns, which are usually presumed to reflect genetic differences. However, lizard life histories are often phenotypically plastic, varying in response to temperature, food availability, and other environmental factors. Despite the importance of temperature to lizard ecology and physiology, its effects on life histories have received relatively little attention. The authors present a theoretical model predicting the proximate consequences of the thermal environment for lizard life histories. Temperature, by affecting activity times, can cause variation in annual survival rate and fecundity, leading to a negative correlation between survival rate and fecundity among populations in different thermal environments. Thus, physiological and evolutionary models predict the same qualitative pattern of life-history variation in lizards. They tested their model with published life-history data from field studies of the lizard Sceloporus undulatus, using climate and geographical data to reconstruct estimated annual activity seasons. Among populations, annual activity times were negatively correlated with annual survival rate and positively correlated with annual fecundity. Proximate effects of temperature may confound comparative analyses of lizard life-history variation and should be included in future evolutionary models. 125 refs., 6 figs., 1 tab.

  7. Personal Narratives in Life History Research

    ERIC Educational Resources Information Center

    Germeten, Sidsel

    2013-01-01

    In this article I discuss how to create personal narratives in life history research methodology. People tell stories of their lives, and the researchers make these stories into life histories. Based on theoretical perspectives on "discourse" inspired by Michel Foucault, narratives are seen as ways of positioning oneself as a…

  8. Temperature, activity, and lizard life histories.

    PubMed

    Adolph, S C; Porter, W P

    1993-08-01

    Lizard life-history characteristics vary widely among species and populations. Most authors seek adaptive or phylogenetic explanations for life-history patterns, which are usually presumed to reflect genetic differences. However, lizard life histories are often phenotypically plastic, varying in response to temperature, food availability, and other environmental factors. Despite the importance of temperature to lizard ecology and physiology, its effects on life histories have received relatively little attention. We present a theoretical model predicting the proximate consequences of the thermal environment for lizard life histories. Temperature, by affecting activity times, can cause variation in annual survival rate and fecundity, leading to a negative correlation between survival rate and fecundity among populations in different thermal environments. Thus, physiological and evolutionary models predict the same qualitative pattern of life-history variation in lizards. We tested our model with published life-history data from field studies of the lizard Sceloporus undulatus, using climate and geographical data to reconstruct estimated annual activity seasons. Among populations, annual activity times were negatively correlated with annual survival rate and positively correlated with annual fecundity. Proximate effects of temperature may confound comparative analyses of lizard life-history variation and should be included in future evolutionary models.

  9. Personal Narratives in Life History Research

    ERIC Educational Resources Information Center

    Germeten, Sidsel

    2013-01-01

    In this article I discuss how to create personal narratives in life history research methodology. People tell stories of their lives, and the researchers make these stories into life histories. Based on theoretical perspectives on "discourse" inspired by Michel Foucault, narratives are seen as ways of positioning oneself as a…

  10. Globalization and Life History Research: Fragments of a Life Foretold

    ERIC Educational Resources Information Center

    Tierney, William G.

    2010-01-01

    The goal of this paper is to understand, by way of a life history of one low-income working-class youth, how globalization impacts the working class in a developing nation. The concept of globalization and the method of life history seem diametrically opposed. Globalization is an idea about large social forces that impact the economic and material…

  11. Globalization and Life History Research: Fragments of a Life Foretold

    ERIC Educational Resources Information Center

    Tierney, William G.

    2010-01-01

    The goal of this paper is to understand, by way of a life history of one low-income working-class youth, how globalization impacts the working class in a developing nation. The concept of globalization and the method of life history seem diametrically opposed. Globalization is an idea about large social forces that impact the economic and material…

  12. End-of-Life Decisions

    MedlinePlus

    ... A living will allows you to put in writing your wishes about medical treatments for the end ... the use of life-sustaining medical treatments in writing as a guide to healthcare providers and loved ...

  13. Reconstructing life history of hominids and humans.

    PubMed

    Crews, Douglas E; Gerber, Linda M

    2003-06-01

    Aspects of life history, such as processes and timing of development, age at maturation, and life span are consistently associated with one another across the animal kingdom. Species that develop rapidly tend to mature and reproduce early, have many offspring, and exhibit shorter life spans (r-selection) than those that develop slowly, have extended periods of premature growth, mature later in life, reproduce later and less frequently, have few offspring and/or single births, and exhibit extended life spans (K-selection). In general, primates are among the most K-selected of species. A suite of highly derived life history traits characterizes humans. Among these are physically immature neonates, slowed somatic development both in utero and post-natally, late attainment of reproductive maturity and first birth, and extended post-mature survival. Exactly when, why, and through what types of evolutionary interactions this suite arose is currently the subject of much conjecture and debate. Humankind's biocultural adaptations have helped to structure human life history evolution in unique ways not seen in other animal species. Among all species, life history traits may respond rapidly to alterations in selective pressures through hormonal processes. Selective pressures on life history likely varied widely among hominids and humans over their evolutionary history. This suggests that current patterns of human growth, development, maturation, reproduction, and post-mature survival may be of recent genesis, rather then long-standing adaptations. Thus, life history patterns observed among contemporary human and chimpanzee populations may provide little insight to those that existed earlier in hominid/human evolution.

  14. Statistical analysis of life history calendar data.

    PubMed

    Eerola, Mervi; Helske, Satu

    2016-04-01

    The life history calendar is a data-collection tool for obtaining reliable retrospective data about life events. To illustrate the analysis of such data, we compare the model-based probabilistic event history analysis and the model-free data mining method, sequence analysis. In event history analysis, we estimate instead of transition hazards the cumulative prediction probabilities of life events in the entire trajectory. In sequence analysis, we compare several dissimilarity metrics and contrast data-driven and user-defined substitution costs. As an example, we study young adults' transition to adulthood as a sequence of events in three life domains. The events define the multistate event history model and the parallel life domains in multidimensional sequence analysis. The relationship between life trajectories and excess depressive symptoms in middle age is further studied by their joint prediction in the multistate model and by regressing the symptom scores on individual-specific cluster indices. The two approaches complement each other in life course analysis; sequence analysis can effectively find typical and atypical life patterns while event history analysis is needed for causal inquiries.

  15. Population momentum across vertebrate life histories

    USGS Publications Warehouse

    Koons, D.N.; Grand, J.B.; Arnold, J.M.

    2006-01-01

    Population abundance is critically important in conservation, management, and demographic theory. Thus, to better understand how perturbations to the life history affect long-term population size, we examined population momentum for four vertebrate classes with different life history strategies. In a series of demographic experiments we show that population momentum generally has a larger effect on long-term population size for organisms with long generation times than for organisms with short generation times. However, patterns between population momentum and generation time varied across taxonomic groups and according to the life history parameter that was changed. Our findings indicate that momentum may be an especially important aspect of population dynamics for long-lived vertebrates, and deserves greater attention in life history studies. Further, we discuss the importance of population momentum in natural resource management, pest control, and conservation arenas. ?? 2006 Elsevier B.V. All rights reserved.

  16. Life-history strategies of ungulates

    USGS Publications Warehouse

    Leslie, David M.; Bowyer, R.T.; Kie, J.G.

    1999-01-01

    This Special Feature resulted from a symposium on life-history strategies of ungulates presented at the 78th Annual Meeting of the American Society of Mammalogists in Blacksburg, Virginia, in June 1998. The presentations at the symposium represented only a vignette of the wide variety of life-history strategies that exists among ungulates. The four papers that follow include treatises on birth-site selection of moose (Alces alces), sex-ratio correlates with dimorphism and risk of predation, optimal foraging relative to risk of predation, and the role of density dependence in shaping life-history traits of ungulates. A theme of risk of predation in shaping life-history traits is common to three of four papers.

  17. Seniors' life histories and perceptions of illness.

    PubMed

    Montbriand, Muriel J

    2004-03-01

    This life history research examined seniors' life experiences and perceived connections to illnesses. From a randomly selected sample of 190 seniors'interviews, 107 deemed to be the most expressive life stories were selected as the focus for this analysis. All seniors lived independently in a Canadian prairie city, were 60 years of age or older, Caucasian, European decent, had a chronic illness, and told of lives touched by the Great Depression and World War II. Given the paucity of research exploring seniors' life histories, these findings increase understanding of how life experiences shape seniors' identities. Four main themes emerged to describe seniors' lives: chaos, tragedy, quest, and romance. Findings reported here show that seniors with optimistic perceptions do not connect their life experiences with illnesses. Seniors with pessimistic perceptions frequently connect their life experiences with present illnesses and are most likely to remember past abuse and coping with abuse.

  18. The Early History of Life

    NASA Astrophysics Data System (ADS)

    Nisbet, E. G.; Fowler, C. M. R.

    2003-12-01

    The youth of the Earth is strange to us. Many of the most fundamental constraints on life may have been different, especially the oxidation state of the surface. Should we suddenly land on its Hadean or early Archean surface by some sci-fi accident, we would not recognize our home. Above, the sky may have been green or some other unworldly color, and above that the weak young Sun might have been unrecognizable to someone trying to identify it from its spectrum. Below, seismology would show a hot, comparatively low-viscosity interior, possibly with a magma ocean in the deeper part of the upper mantle (Drake and Righter, 2002; Nisbet and Walker, 1982), and a core that, though present, was perhaps rather smaller than today. The continents may have been small islands in an icy sea, mostly frozen with some leads of open water, ( Sleep et al., 2001). Into these icy oceans, huge protruding Hawaii-like volcanoes would have poured out vast far-spreading floods of komatiite lavas in immense eruptions that may have created sudden local hypercane storms to disrupt the nearby icebergs. And meteorites would rain down.Or perhaps it was not so strange, nor so violent. The child is father to the man; young Earth was mother to Old Earth. Earth had hydrogen, silicate rock below and on the surface abundant carbon, which her ancient self retains today. Moreover, Earth was oxygen-rich, as today. Today, a tiny part of the oxygen is free, as air; then the oxygen would have been in the mantle while the surface oxygen was used to handcuff the hydrogen as dihydrogen monoxide. Oxygen dihydride is dense, unlikely to fly off to space, and at the poles, rock-forming. Of all the geochemical features that make Earth unique, the initial degassing (Genesis 2 : b) and then the sustained presence of liquid water is the defining oddity of this planet. Early Earth probably also kept much of its carbon, nitrogen, and sulfur as oxide or hydride. And, after the most cataclysmic events had passed, ˜4.5 Ga

  19. Consent and end of life decisions

    PubMed Central

    Harris, J.

    2003-01-01

    This paper discusses the role of consent in decision making generally and its role in end of life decisions in particular. It outlines a conception of autonomy which explains and justifies the role of consent in decision making and criticises some misapplications of the idea of consent, particular the role of fictitious or "proxy" consents. Where the inevitable outcome of a decision must be that a human individual will die and where that individual is a person who can consent, then that decision is ethical if and only if the individual consents. In very rare and extreme cases such a decision will be ethical in the absence of consent where it would be massively cruel not to end life in order to prevent suffering which is in no other way preventable. Where, however, the human individual is not a person, as is the case with abortion, the death of infants like Mary (one of the conjoined twins in a case discussed in the paper), or in the very rare and extreme cases of those who have ceased to be persons like Tony Bland, such decisions are governed by the ethics of ending the lives of non-persons. PMID:12569187

  20. Consent and end of life decisions.

    PubMed

    Harris, John

    2003-02-01

    This paper discusses the role of consent in decision making generally and its role in end of life decisions in particular. It outlines a conception of autonomy which explains and justifies the role of consent in decision making and criticises some misapplications of the idea of consent, particular the role of fictitious or "proxy" consents. Where the inevitable outcome of a decision must be that a human individual will die and where that individual is a person who can consent, then that decision is ethical if and only if the individual consents. In very rare and extreme cases such a decision will be ethical in the absence of consent where it would be massively cruel not to end life in order to prevent suffering which is in no other way preventable. Where, however, the human individual is not a person, as is the case with abortion, the death of infants like Mary (one of the conjoined twins in a case discussed in the paper), or in the very rare and extreme cases of those who have ceased to be persons like Tony Bland, such decisions are governed by the ethics of ending the lives of non-persons.

  1. America: History and Life Online: History and Much More.

    ERIC Educational Resources Information Center

    Falk, Joyce Duncan

    1983-01-01

    This guide to searching for "America: History and Life," a bibliographic database offering resources on topics in social sciences, humanities, and arts in the United States and Canada, covers subject scope, selection and coverage, document types and records, combined entries, subject indexing, personal names, geographic names, historical periods,…

  2. End-of-life decisions in neonates.

    PubMed

    Kollée, L A; van der Heide, A; de Leeuw, R; van der Maas, P J; van der Wal, G

    1999-06-01

    In a large percentage of the infants who die in the neonatal intensive care setting, an end-of-life decision was made before death, usually a decision to forego life-sustaining treatment. This was confirmed in a recent study in The Netherlands that showed also that a minority of cases include the administration of drugs to hasten death, usually in patients with severe congenital multiple or central nervous system anomalies. Over 80% of Dutch pediatricians support this option under certain conditions. Almost all pediatricians are of the opinion that these cases have to be subject to public review, but they favor review by a committee of independent medical, judicial, and ethical professionals rather than by the public prosecutor. A discussion group on this subject recently made a proposal for such a reviewing procedure to the Dutch governmental authorities and described the requirements concerning end-of-life decisions in neonatal medicine. Proper handling of ethical aspects of medical treatment including review and feedback after end-of-life decisions can contribute to high standards of quality of care.

  3. Life history diversity in Klamath River steelhead

    USGS Publications Warehouse

    Hodge, Brian W.; Wilzbach, Peggy; Duffy, Walter G.; Quinones, Rebecca M.; Hobbs, James A.

    2016-01-01

    Oncorhynchus mykiss exhibits a vast array of life histories, which increases its likelihood of persistence by spreading risk of extirpation among different pathways. The Klamath River basin (California–Oregon) provides a particularly interesting backdrop for the study of life history diversity in O. mykiss, in part because the river is slated for a historic and potentially influential dam removal and habitat recolonization project. We used scale and otolith strontium isotope (87Sr/86Sr) analyses to characterize life history diversity in wildO. mykiss from the lower Klamath River basin. We also determined maternal origin (anadromous or nonanadromous) and migratory history (anadromous or nonanadromous) of O. mykiss and compared length and fecundity at age between anadromous (steelhead) and nonanadromous (Rainbow Trout) phenotypes of O. mykiss. We identified a total of 38 life history categories at maturity, which differed in duration of freshwater and ocean rearing, age at maturation, and incidence of repeat spawning. Approximately 10% of adult fish sampled were nonanadromous. Rainbow Trout generally grew faster in freshwater than juvenile steelhead; however, ocean growth afforded adult steelhead greater length and fecundity than adult Rainbow Trout. Although 75% of individuals followed the migratory path of their mother, steelhead produced nonanadromous progeny and Rainbow Trout produced anadromous progeny. Overall, we observed a highly diverse array of life histories among Klamath River O. mykiss. While this diversity should increase population resilience, recent declines in the abundance of Klamath River steelhead suggest that life history diversity alone is not sufficient to stabilize a population. Our finding that steelhead and Rainbow Trout give rise to progeny of the alternate form (1) suggests that dam removal might lead to a facultatively anadromous O. mykiss population in the upper basin and (2) raises the question of whether both forms of

  4. Lemur Biorhythms and Life History Evolution

    PubMed Central

    Hogg, Russell T.; Godfrey, Laurie R.; Schwartz, Gary T.; Dirks, Wendy; Bromage, Timothy G.

    2015-01-01

    Skeletal histology supports the hypothesis that primate life histories are regulated by a neuroendocrine rhythm, the Havers-Halberg Oscillation (HHO). Interestingly, subfossil lemurs are outliers in HHO scaling relationships that have been discovered for haplorhine primates and other mammals. We present new data to determine whether these species represent the general lemur or strepsirrhine condition and to inform models about neuroendocrine-mediated life history evolution. We gathered the largest sample to date of HHO data from histological sections of primate teeth (including the subfossil lemurs) to assess the relationship of these chronobiological measures with life history-related variables including body mass, brain size, age at first female reproduction, and activity level. For anthropoids, these variables show strong correlations with HHO conforming to predictions, though body mass and endocranial volume are strongly correlated with HHO periodicity in this group. However, lemurs (possibly excepting Daubentonia) do not follow this pattern and show markedly less variability in HHO periodicity and lower correlation coefficients and slopes. Moreover, body mass is uncorrelated, and brain size and activity levels are more strongly correlated with HHO periodicity in these animals. We argue that lemurs evolved this pattern due to selection for risk-averse life histories driven by the unpredictability of the environment in Madagascar. These results reinforce the idea that HHO influences life history evolution differently in response to specific ecological selection regimes. PMID:26267241

  5. Lemur Biorhythms and Life History Evolution.

    PubMed

    Hogg, Russell T; Godfrey, Laurie R; Schwartz, Gary T; Dirks, Wendy; Bromage, Timothy G

    2015-01-01

    Skeletal histology supports the hypothesis that primate life histories are regulated by a neuroendocrine rhythm, the Havers-Halberg Oscillation (HHO). Interestingly, subfossil lemurs are outliers in HHO scaling relationships that have been discovered for haplorhine primates and other mammals. We present new data to determine whether these species represent the general lemur or strepsirrhine condition and to inform models about neuroendocrine-mediated life history evolution. We gathered the largest sample to date of HHO data from histological sections of primate teeth (including the subfossil lemurs) to assess the relationship of these chronobiological measures with life history-related variables including body mass, brain size, age at first female reproduction, and activity level. For anthropoids, these variables show strong correlations with HHO conforming to predictions, though body mass and endocranial volume are strongly correlated with HHO periodicity in this group. However, lemurs (possibly excepting Daubentonia) do not follow this pattern and show markedly less variability in HHO periodicity and lower correlation coefficients and slopes. Moreover, body mass is uncorrelated, and brain size and activity levels are more strongly correlated with HHO periodicity in these animals. We argue that lemurs evolved this pattern due to selection for risk-averse life histories driven by the unpredictability of the environment in Madagascar. These results reinforce the idea that HHO influences life history evolution differently in response to specific ecological selection regimes.

  6. Deciphering life history transcriptomes in different environments

    PubMed Central

    Etges, William J.; Trotter, Meredith V.; de Oliveira, Cássia C.; Rajpurohit, Subhash; Gibbs, Allen G.; Tuljapurkar, Shripad

    2014-01-01

    We compared whole transcriptome variation in six preadult stages and seven adult female ages in two populations of cactophilic Drosophila mojavensis reared on two host plants in order to understand how differences in gene expression influence standing life history variation. We used Singular Value Decomposition (SVD) to identify dominant trajectories of life cycle gene expression variation, performed pair-wise comparisons of stage and age differences in gene expression across the life cycle, identified when genes exhibited maximum levels of life cycle gene expression, and assessed population and host cactus effects on gene expression. Life cycle SVD analysis returned four significant components of transcriptional variation, revealing functional enrichment of genes responsible for growth, metabolic function, sensory perception, neural function, translation and aging. Host cactus effects on female gene expression revealed population and stage specific differences, including significant host plant effects on larval metabolism and development, as well as adult neurotransmitter binding and courtship behavior gene expression levels. In 3 - 6 day old virgin females, significant up-regulation of genes associated with meiosis and oogenesis was accompanied by down-regulation of genes associated with somatic maintenance, evidence for a life history tradeoff. The transcriptome of D. mojavensis reared in natural environments throughout its life cycle revealed core developmental transitions and genome wide influences on life history variation in natural populations. PMID:25442828

  7. Deciphering life history transcriptomes in different environments.

    PubMed

    Etges, William J; Trotter, Meredith V; de Oliveira, Cássia C; Rajpurohit, Subhash; Gibbs, Allen G; Tuljapurkar, Shripad

    2015-01-01

    We compared whole transcriptome variation in six pre-adult stages and seven adult female ages in two populations of cactophilic Drosophila mojavensis reared on two host plants to understand how differences in gene expression influence standing life history variation. We used singular value decomposition (SVD) to identify dominant trajectories of life cycle gene expression variation, performed pairwise comparisons of stage and age differences in gene expression across the life cycle, identified when genes exhibited maximum levels of life cycle gene expression, and assessed population and host cactus effects on gene expression. Life cycle SVD analysis returned four significant components of transcriptional variation, revealing functional enrichment of genes responsible for growth, metabolic function, sensory perception, neural function, translation and ageing. Host cactus effects on female gene expression revealed population- and stage-specific differences, including significant host plant effects on larval metabolism and development, as well as adult neurotransmitter binding and courtship behaviour gene expression levels. In 3- to 6-day-old virgin females, significant upregulation of genes associated with meiosis and oogenesis was accompanied by downregulation of genes associated with somatic maintenance, evidence for a life history trade-off. The transcriptome of D. mojavensis reared in natural environments throughout its life cycle revealed core developmental transitions and genome-wide influences on life history variation in natural populations.

  8. Life history evolution: successes, limitations, and prospects

    NASA Astrophysics Data System (ADS)

    Stearns, Stephen C.

    Life history theory tries to explain how evolution designs organisms to achieve reproductive success. The design is a solution to an ecological problem posed by the environment and subject to constraints intrinsic to the organism. Work on life histories has expanded the role of phenotypes in evolutionary theory, extending the range of predictions from genetic patterns to whole-organism traits directly connected to fitness. Among the questions answered are the following: Why are organisms small or large? Why do they mature early or late? Why do they have few or many offspring? Why do they have a short or a long life? Why must they grow old and die? The classical approach to life histories was optimization; it has had some convincing empirical success. Recently non-equilibrium approaches involving frequency-dependence, density-dependence, evolutionary game theory, adaptive dynamics, and explicit population dynamics have supplanted optimization as the preferred approach. They have not yet had as much empirical success, but there are logical reasons to prefer them, and they may soon extend the impact of life history theory into population dynamics and interspecific interactions in coevolving communities.

  9. ELASTICITY ANALYSIS OF AMPHIBIAN LIFE HISTORIES

    EPA Science Inventory

    By comparing life history parameters (e.g., age at metamorphosis, age at sexual maturation, egg number, longevity) and phenology of different species, we gain valuable insight into why growth rates differ across populations. Although the demography of most amphibians is lacking, ...

  10. Parasite stress, ethnocentrism, and life history strategy.

    PubMed

    Figueredo, Aurelio José; Gladden, Paul Robert; Black, Candace Jasmine

    2012-04-01

    Fincher & Thornhill (F&T) present a compelling argument that parasite stress underlies certain cultural practices promoting assortative sociality. However, we suggest that the theoretical framework proposed is limited in several ways, and that life history theory provides a more explanatory and inclusive framework, making more specific predictions about the trade-offs faced by organisms in the allocation of bioenergetic and material resources.

  11. ELASTICITY ANALYSIS OF AMPHIBIAN LIFE HISTORIES

    EPA Science Inventory

    By comparing life history parameters (e.g., age at metamorphosis, age at sexual maturation, egg number, longevity) and phenology of different species, we gain valuable insight into why growth rates differ across populations. Although the demography of most amphibians is lacking, ...

  12. The life history of neochromosomes revealed

    PubMed Central

    Papenfuss, Anthony T; Thomas, David M

    2015-01-01

    Neochromosomes are a little-studied class of chromosome-scale mutations that drive some cancers. By sequencing isolated neochromosomes from liposarcomas, we recently defined their structure at single-nucleotide resolution and proposed a model for their life history. Here, we summarize that work, highlighting significant aspects and providing historical context and insight into the discovery process. PMID:27308490

  13. Regents Make History: The DNA Decision

    ERIC Educational Resources Information Center

    Gies, Joseph C.

    1977-01-01

    A routine-sounding request for a science lab renovation grew into a controversy with immense implications: Is DNA research safe? Does it belong on campus? Is it beyond human capacity to control? The decision-making role of the University of Michigan regents is described. (Editor/LBH)

  14. "Life history space": a multivariate analysis of life history variation in extant and extinct Malagasy lemurs.

    PubMed

    Catlett, Kierstin K; Schwartz, Gary T; Godfrey, Laurie R; Jungers, William L

    2010-07-01

    Studies of primate life history variation are constrained by the fact that all large-bodied extant primates are haplorhines. However, large-bodied strepsirrhines recently existed. If we can extract life history information from their skeletons, these species can contribute to our understanding of primate life history variation. This is particularly important in light of new critiques of the classic "fast-slow continuum" as a descriptor of variation in life history profiles across mammals in general. We use established dental histological methods to estimate gestation length and age at weaning for five extinct lemur species. On the basis of these estimates, we reconstruct minimum interbirth intervals and maximum reproductive rates. We utilize principal components analysis to create a multivariate "life history space" that captures the relationships among reproductive parameters and brain and body size in extinct and extant lemurs. Our data show that, whereas large-bodied extinct lemurs can be described as "slow" in some fashion, they also varied greatly in their life history profiles. Those with relatively large brains also weaned their offspring late and had long interbirth intervals. These were not the largest of extinct lemurs. Thus, we distinguish size-related life history variation from variation that linked more strongly to ecological factors. Because all lemur species larger than 10 kg, regardless of life history profile, succumbed to extinction after humans arrived in Madagascar, we argue that large body size increased the probability of extinction independently of reproductive rate. We also provide some evidence that, among lemurs, brain size predicts reproductive rate better than body size. (c) 2010 Wiley-Liss, Inc.

  15. Allometric scaling of plant life history.

    PubMed

    Marbà, Núria; Duarte, Carlos M; Agustí, Susana

    2007-10-02

    Plant mortality and birth rates are critical components of plant life history affecting the stability of plant populations and the ecosystems they form. Although allometric theory predicts that both plant birth and mortality rates should be size-dependent, this prediction has not yet been tested across plants ranging the full size spectrum. Here we show that both population mortality and population birth rates scale as the -(1/4) power and plant lifespan as the (1/4) power of plant mass across plant species spanning from the tiniest phototrophs to the largest trees. Whereas the controls on plant lifespans are as yet poorly understood, our findings suggest that plant mortality rates have evolved to match population birth rates, thereby helping to maintain plant communities in equilibrium and optimizing plant life histories.

  16. Grandmothering life histories and human pair bonding

    PubMed Central

    Coxworth, James E.; Kim, Peter S.; McQueen, John S.; Hawkes, Kristen

    2015-01-01

    The evolution of distinctively human life history and social organization is generally attributed to paternal provisioning based on pair bonds. Here we develop an alternative argument that connects the evolution of human pair bonds to the male-biased mating sex ratios that accompanied the evolution of human life history. We simulate an agent-based model of the grandmother hypothesis, compare simulated sex ratios to data on great apes and human hunter–gatherers, and note associations between a preponderance of males and mate guarding across taxa. Then we explore a recent model that highlights the importance of mating sex ratios for differences between birds and mammals and conclude that lessons for human evolution cannot ignore mammalian reproductive constraints. In contradiction to our claim that male-biased sex ratios are characteristically human, female-biased ratios are reported in some populations. We consider the likelihood that fertile men are undercounted and conclude that the mate-guarding hypothesis for human pair bonds gains strength from explicit links with our grandmothering life history. PMID:26351687

  17. Professional Identity as Learning Processes in Life Histories. Roskilde University Life History Project Paper.

    ERIC Educational Resources Information Center

    Salling Olesen, Henning

    The question of how to theorize the subjective side of work within a life history perspective was explored. The findings of a study on engineers' subjective recognition of their lives, their education and jobs, and their life perspectives and the findings of a study of continuing education within a number of white-collar and semiprofessional work…

  18. Great revolutions in the history of life.

    PubMed

    Seilacher, A

    1997-03-25

    Evolution is a historical process. Like human history its course is unpredictable, because it results from the response of organisms and their biographies to changing outside conditions. Yet it makes perfect sense in retrospect, because every move was conditioned by the previous one. Another characteristic of historical changes is that they proceed gradually on the one hand, but are accentuated by events on the other. With regard to human history, one has always emphasized the events, such as wars and political revolutions; only recently historians got also interested in the more gradual changes in everyday life during the intervening periods. In evolutionary biology, emphasis was reversed. Darwinian theory focuses in gradual transformations, because this is what we can directly observe in natural and domesticated populations. Therefore the breaks that paleontologists noted in the fossil record were for a long time considered as preservational artifacts. Today we know that they reflect real evolutionary cascades induced by environmental perturbations of higher order. We are also becoming aware that the impact of our own species on the global environment could mark such a break which a few million years later will be taken as the end of the Cenozoic and the beginning of a new era, the "Anthropozoic". With such perspectives in mind we shall now study the patterns of the great revolutions in the history of life, back to the greatest of all, the "Cambrian Explosion".

  19. The Psychometric Evaluation of Human Life Histories.

    PubMed

    Copping, Lee T; Campbell, Anne; Muncer, Steven; Richardson, George B

    2017-01-01

    A recent critique of Copping, Campbell, and Muncer raised several issues concerning the validity of psychometric assessment techniques in the study of life history (LH) strategies. In this reply, some of our key concerns about relying on aggregated psychometric measures are explained, and we raise questions generally regarding the use of higher order factor structures. Responses to some of the statistical issues raised by Figueredo et al. are also detailed. We stand by our original conclusions and call for more careful consideration of instruments used to evaluate hypotheses derived from LH theory.

  20. Immune defense and host life history.

    PubMed

    Zuk, Marlene; Stoehr, Andrew M

    2002-10-01

    Recent interest has focused on immune response in an evolutionary context, with particular attention to disease resistance as a life-history trait, subject to trade-offs against other traits such as reproductive effort. Immune defense has several characteristics that complicate this approach, however; for example, because of the risk of autoimmunity, optimal immune defense is not necessarily maximum immune defense. Two important types of cost associated with immunity in the context of life history are resource costs, those related to the allocation of essential but limited resources, such as energy or nutrients, and option costs, those paid not in the currency of resources but in functional or structural components of the organism. Resource and option costs are likely to apply to different aspects of resistance. Recent investigations into possible trade-offs between reproductive effort, particularly sexual displays, and immunity have suggested interesting functional links between the two. Although all organisms balance the costs of immune defense against the requirements of reproduction, this balance works out differently for males than it does for females, creating sex differences in immune response that in turn are related to ecological factors such as the mating system. We conclude that immune response is indeed costly and that future work would do well to include invertebrates, which have sometimes been neglected in studies of the ecology of immune defense.

  1. Predicting life-history adaptations to pollutants

    SciTech Connect

    Maltby, L.

    1995-12-31

    Animals may adapt to pollutant stress so that individuals from polluted environments are less susceptible than those from unpolluted environments. In addition to such direct adaptations, animals may respond to pollutant stress by life-history modifications; so-called indirect adaptations. This paper will demonstrate how, by combining life-history theory and toxicological data, it is possible to predict stress-induced alterations in reproductive output and offspring size. Pollutant-induced alterations in age-specific survival in favor of adults and reductions in juvenile growth, conditions are predicted to select for reduced investment in reproduction and the allocation of this investment into fewer, larger offspring. Field observations on the freshwater crustaceans, Asellus aquaticus and Gammarus pulex, support these predictions. Females from metal-polluted sites had lower investment in reproduction and produced larger offspring than females of the same species from unpolluted sites. Moreover, interpopulation differences in reproductive biology persisted in laboratory cultures indicating that they had a genetic basis and were therefore due to adaptation rather than acclimation. The general applicability of this approach will be considered.

  2. Martha E. Rogers: a life history.

    PubMed

    Hektor, L M

    1989-01-01

    The 20th century in nursing has focused heavily on theory development. While theorizing about nursing--what it is, and what it is not--can be traced back to Nightingale, Martha E. Rogers' An Introduction to the Theoretical Basis of Nursing (1970) marked the advent of a new era in nursing science. With a view of nursing as a "learned profession," this landmark work staked out a substantive knowledge base for the discipline. The science of unitary human beings proposed by Rogers was a radical departure from all that had come before and is seen by many as pioneering the beginning of a paradigmatic shift within the profession. The purpose of this inquiry is to document the self-described events across the life span of Martha E. Rogers that she perceived as having influenced the development of the science of unitary human beings. A life history approach is utilized and the data are organized chronologically. This life story of Martha E. Rogers is essential to the current and future understanding of the evolution of the culture of nursing. Likewise, more is learned about the nature and process of theory development.

  3. Dynamic Model for Life History of Scyphozoa.

    PubMed

    Xie, Congbo; Fan, Meng; Wang, Xin; Chen, Ming

    2015-01-01

    A two-state life history model governed by ODEs is formulated to elucidate the population dynamics of jellyfish and to illuminate the triggering mechanism of its blooms. The polyp-medusa model admits trichotomous global dynamic scenarios: extinction, polyps survival only, and both survival. The population dynamics sensitively depend on several biotic and abiotic limiting factors such as substrate, temperature, and predation. The combination of temperature increase, substrate expansion, and predator diminishment acts synergistically to create a habitat that is more favorable for jellyfishes. Reducing artificial marine constructions, aiding predator populations, and directly controlling the jellyfish population would help to manage the jellyfish blooms. The theoretical analyses and numerical experiments yield several insights into the nature underlying the model and shed some new light on the general control strategy for jellyfish.

  4. Dynamic Model for Life History of Scyphozoa

    PubMed Central

    Xie, Congbo; Fan, Meng; Wang, Xin; Chen, Ming

    2015-01-01

    A two-state life history model governed by ODEs is formulated to elucidate the population dynamics of jellyfish and to illuminate the triggering mechanism of its blooms. The polyp-medusa model admits trichotomous global dynamic scenarios: extinction, polyps survival only, and both survival. The population dynamics sensitively depend on several biotic and abiotic limiting factors such as substrate, temperature, and predation. The combination of temperature increase, substrate expansion, and predator diminishment acts synergistically to create a habitat that is more favorable for jellyfishes. Reducing artificial marine constructions, aiding predator populations, and directly controlling the jellyfish population would help to manage the jellyfish blooms. The theoretical analyses and numerical experiments yield several insights into the nature underlying the model and shed some new light on the general control strategy for jellyfish. PMID:26114642

  5. A model for brain life history evolution

    PubMed Central

    Lehmann, Laurent

    2017-01-01

    Complex cognition and relatively large brains are distributed across various taxa, and many primarily verbal hypotheses exist to explain such diversity. Yet, mathematical approaches formalizing verbal hypotheses would help deepen the understanding of brain and cognition evolution. With this aim, we combine elements of life history and metabolic theories to formulate a metabolically explicit mathematical model for brain life history evolution. We assume that some of the brain’s energetic expense is due to production (learning) and maintenance (memory) of energy-extraction skills (or cognitive abilities, knowledge, information, etc.). We also assume that individuals use such skills to extract energy from the environment, and can allocate this energy to grow and maintain the body, including brain and reproductive tissues. The model can be used to ask what fraction of growth energy should be allocated at each age, given natural selection, to growing brain and other tissues under various biological settings. We apply the model to find uninvadable allocation strategies under a baseline setting (“me vs nature”), namely when energy-extraction challenges are environmentally determined and are overcome individually but possibly with maternal help, and use modern-human data to estimate model’s parameter values. The resulting uninvadable strategies yield predictions for brain and body mass throughout ontogeny and for the ages at maturity, adulthood, and brain growth arrest. We find that: (1) a me-vs-nature setting is enough to generate adult brain and body mass of ancient human scale and a sequence of childhood, adolescence, and adulthood stages; (2) large brains are favored by intermediately challenging environments, moderately effective skills, and metabolically expensive memory; and (3) adult skill is proportional to brain mass when metabolic costs of memory saturate the brain metabolic rate allocated to skills. PMID:28278153

  6. A model for brain life history evolution.

    PubMed

    González-Forero, Mauricio; Faulwasser, Timm; Lehmann, Laurent

    2017-03-01

    Complex cognition and relatively large brains are distributed across various taxa, and many primarily verbal hypotheses exist to explain such diversity. Yet, mathematical approaches formalizing verbal hypotheses would help deepen the understanding of brain and cognition evolution. With this aim, we combine elements of life history and metabolic theories to formulate a metabolically explicit mathematical model for brain life history evolution. We assume that some of the brain's energetic expense is due to production (learning) and maintenance (memory) of energy-extraction skills (or cognitive abilities, knowledge, information, etc.). We also assume that individuals use such skills to extract energy from the environment, and can allocate this energy to grow and maintain the body, including brain and reproductive tissues. The model can be used to ask what fraction of growth energy should be allocated at each age, given natural selection, to growing brain and other tissues under various biological settings. We apply the model to find uninvadable allocation strategies under a baseline setting ("me vs nature"), namely when energy-extraction challenges are environmentally determined and are overcome individually but possibly with maternal help, and use modern-human data to estimate model's parameter values. The resulting uninvadable strategies yield predictions for brain and body mass throughout ontogeny and for the ages at maturity, adulthood, and brain growth arrest. We find that: (1) a me-vs-nature setting is enough to generate adult brain and body mass of ancient human scale and a sequence of childhood, adolescence, and adulthood stages; (2) large brains are favored by intermediately challenging environments, moderately effective skills, and metabolically expensive memory; and (3) adult skill is proportional to brain mass when metabolic costs of memory saturate the brain metabolic rate allocated to skills.

  7. The effect of social environment during ontogeny on life history expression in the guppy Poecilia reticulata.

    PubMed

    Magellan, K; Magurran, A E

    2009-07-01

    The effects of the social environment during development on life-history decisions and adult behaviour were assessed using male guppies Poecilia reticulata. Males raised with adults developed secondary sexual characteristics later than males raised either singly or with four of their siblings indicating social inhibition of maturation was evident in P. reticulata. There was no effect, however, of rearing environment on male behaviour. The results reveal that social environment during development can influence life-history decisions but is less important than immediate social context in determining male behavioural phenotype in P. reticulata.

  8. End-of-life decisions in dutch neonatology.

    PubMed

    Moratti, Sofia

    2010-01-01

    This contribution describes the regulation of end-of-life decisions in neonatology in the Netherlands. An account is given of the process of formulating rules, which includes a report by the Dutch Association for Paediatrics, two Court rulings, a report by a Consultation Group appointed by the Ministry of Health and a professional Protocol regulating deliberate ending of life in neonatology that was subsequently adopted as the regulation of this type of decision-making at the national level. The paper presents Dutch and comparative data on the attitude of the medical profession towards end-of-life decisions in neonatology and the frequency of such decisions in medical practice.

  9. Biological invasion and biological control select for different life histories

    PubMed Central

    Tayeh, Ashraf; Hufbauer, Ruth A.; Estoup, Arnaud; Ravigné, Virginie; Frachon, Léa; Facon, Benoit

    2015-01-01

    Biological invaders have long been hypothesized to exhibit the fast end of the life-history spectrum, with early reproduction and a short lifespan. Here, we examine the rapid evolution of life history within the harlequin ladybird Harmonia axyridis. The species, once used as a biological control agent, is now a worldwide invader. We show that biocontrol populations have evolved a classic fast life history during their maintenance in laboratories. Invasive populations also reproduce earlier than native populations, but later than biocontrol ones. Invaders allocate more resources to reproduction than native and biocontrol individuals, and their reproduction is spread over a longer lifespan. This life history is best described as a bet-hedging strategy. We assert that invasiveness cannot be explained only by invoking faster life histories. Instead, the evolution of life history within invasive populations can progress rapidly and converge to a fine-tuned evolutionary match between the invaded environment and the invader. PMID:26035519

  10. LIFE HISTORY. Age-related mortality explains life history strategies of tropical and temperate songbirds.

    PubMed

    Martin, Thomas E

    2015-08-28

    Life history theory attempts to explain why species differ in offspring number and quality, growth rate, and parental effort. I show that unappreciated interactions of these traits in response to age-related mortality risk challenge traditional perspectives and explain life history evolution in songbirds. Counter to a long-standing paradigm, tropical songbirds grow at similar overall rates to temperate species but grow wings relatively faster. These growth tactics are favored by predation risk, both in and after leaving the nest, and are facilitated by greater provisioning of individual offspring by parents. Increased provisioning of individual offspring depends on partitioning effort among fewer young because of constraints on effort from adult and nest mortality. These growth and provisioning responses to mortality risk finally explain the conundrum of small clutch sizes of tropical birds.

  11. Elders' end-of-life decisions: implications for hospice care.

    PubMed

    Cicirelli, V G

    1997-01-01

    Elders' views on various end-of-life decision options were studied to determine each option's acceptability if they were faced with the need for such decisions. 388 black and white elders aged 60 to 100 responded to 17 decision scenarios depicting situations with a low quality of life, rating acceptability of each of 7 options for each scenario. Based on factor analysis of responses over scenarios, three scores were computed: maintaining life, ending life, and letting others decide. Profile types were identified and related to demographic background and personality variables. Implications for hospice care are drawn.

  12. When divergent life histories hybridize: insights into adaptive life-history traits in an annual weed.

    PubMed

    Campbell, Lesley G; Snow, Allison A; Sweeney, Patricia M

    2009-12-01

    *Colonizing weed populations face novel selective environments, which may drive rapid shifts in life history. These shifts may be amplified when colonists are hybrids of species with divergent life histories. Selection on such phenotypically diverse hybrids may create highly fecund weeds. We measured the phenotypic variation, strength of natural selection and evolutionary response of hybrid and nonhybrid weeds. *We created F(1) hybrids of wild radish, an early flowering, small-stemmed weed, and its late-flowering, large-stemmed, crop relative (Raphanus spp.). Replicate wild and hybrid populations were established in an agricultural landscape in Michigan, USA. The consequences of three generations of natural selection were measured in a common garden experiment. *Hybrid populations experienced strong selection for larger, earlier flowering plants whereas selection was relatively weak on wild populations. Large plant size evolved two to three times faster in the hybrid populations than in wild populations, yet hybrid populations did not evolve earlier flowering. Strong selection on size and phenotypic correlations between age at reproduction and size may have limited the response of flowering phenology. *Our findings demonstrate hybridization between species with divergent life histories may catalyse the rapid evolution of certain adaptive, weedy traits while tradeoffs limit the evolution of others.

  13. Primates and the evolution of long, slow life histories.

    PubMed

    Jones, James Holland

    2011-09-27

    Primates are characterized by relatively late ages at first reproduction, long lives and low fertility. Together, these traits define a life-history of reduced reproductive effort. Understanding the optimal allocation of reproductive effort, and specifically reduced reproductive effort, has been one of the key problems motivating the development of life-history theory. Because of their unusual constellation of life-history traits, primates play an important role in the continued development of life-history theory. In this review, I present the evidence for the reduced reproductive effort life histories of primates and discuss the ways that such life-history tactics are understood in contemporary theory. Such tactics are particularly consistent with the predictions of stochastic demographic models, suggesting a key role for environmental variability in the evolution of primate life histories. The tendency for primates to specialize in high-quality, high-variability food items may make them particularly susceptible to environmental variability and explains their low reproductive-effort tactics. I discuss recent applications of life-history theory to human evolution and emphasize the continuity between models used to explain peculiarities of human reproduction and senescence with the long, slow life histories of primates more generally.

  14. Primates and the Evolution of Long-Slow Life Histories

    PubMed Central

    Jones, James Holland

    2011-01-01

    Summary Primates are characterized by relatively late ages at first reproduction, long lives and low fertility. Together, these traits define a life-history of reduced reproductive effort. Understanding the optimal allocation of reproductive effort, and specifically reduced reproductive effort, has been one of the key problems motivating the development of life history theory. Because of their unusual constellation of life-history traits, primates play an important role in the continued development of life history theory. In this review, I present the evidence for the reduced reproductive effort life histories of primates and discuss the ways that such life-history tactics are understood in contemporary theory. Such tactics are particularly consistent with the predictions of stochastic demographic models, suggesting a key role for environmental variability in the evolution of primate life histories. The tendency for primates to specialize in high-quality, high-variability food items may make them particularly susceptible to environmental variability and explain their low reproductive-effort tactics. I discuss recent applications of life history theory to human evolution and emphasize the continuity between models used to explain peculiarities of human reproduction and senescence with the long, slow life histories of primates more generally. PMID:21959161

  15. Variability in the developmental life history of the genus Gorilla.

    PubMed

    Stoinski, Tara S; Perdue, Bonnie; Breuer, Thomas; Hoff, Michael P

    2013-10-01

    Life history is influenced by factors both intrinsic (e.g., body and relative brain size) and extrinsic (e.g., diet, environmental instability) to organisms. In this study, we examine the prediction that energetic risk influences the life history of gorillas. Recent comparisons suggest that the more frugivorous western lowland gorilla shows increased infant dependence, and thus a slower life history, than the primarily folivorous mountain gorilla to buffer against the risk of starvation during periods of food unpredictability. We further tested this hypothesis by incorporating additional life history data from wild western lowland gorillas and captive western lowland gorillas with the assumption that the latter live under ecological conditions of energetic risk that more closely resemble those of mountain gorillas and thus should show faster life histories than wild members of the species. Overall, we found captive western lowland and wild mountain gorillas to have faster developmental life histories than wild western lowland gorillas, weaning their infants approximately a year earlier and thus reducing interbirth intervals by a year. These results provide support that energetic risk plays an important role in determining gorilla life history. Unlike previous assertions, gorillas do not have substantially faster life histories, at least at the genus level, than other great apes. This calls for a re-evaluation of theories concerning comparative ape life history and evolution and highlights the need for data from additional populations that vary in energetic risk.

  16. The Life History of 21 Breast Cancers

    PubMed Central

    Nik-Zainal, Serena; Van Loo, Peter; Wedge, David C.; Alexandrov, Ludmil B.; Greenman, Christopher D.; Lau, King Wai; Raine, Keiran; Jones, David; Marshall, John; Ramakrishna, Manasa; Shlien, Adam; Cooke, Susanna L.; Hinton, Jonathan; Menzies, Andrew; Stebbings, Lucy A.; Leroy, Catherine; Jia, Mingming; Rance, Richard; Mudie, Laura J.; Gamble, Stephen J.; Stephens, Philip J.; McLaren, Stuart; Tarpey, Patrick S.; Papaemmanuil, Elli; Davies, Helen R.; Varela, Ignacio; McBride, David J.; Bignell, Graham R.; Leung, Kenric; Butler, Adam P.; Teague, Jon W.; Martin, Sancha; Jönsson, Goran; Mariani, Odette; Boyault, Sandrine; Miron, Penelope; Fatima, Aquila; Langerød, Anita; Aparicio, Samuel A.J.R.; Tutt, Andrew; Sieuwerts, Anieta M.; Borg, Åke; Thomas, Gilles; Salomon, Anne Vincent; Richardson, Andrea L.; Børresen-Dale, Anne-Lise; Futreal, P. Andrew; Stratton, Michael R.; Campbell, Peter J.

    2012-01-01

    Summary Cancer evolves dynamically as clonal expansions supersede one another driven by shifting selective pressures, mutational processes, and disrupted cancer genes. These processes mark the genome, such that a cancer's life history is encrypted in the somatic mutations present. We developed algorithms to decipher this narrative and applied them to 21 breast cancers. Mutational processes evolve across a cancer's lifespan, with many emerging late but contributing extensive genetic variation. Subclonal diversification is prominent, and most mutations are found in just a fraction of tumor cells. Every tumor has a dominant subclonal lineage, representing more than 50% of tumor cells. Minimal expansion of these subclones occurs until many hundreds to thousands of mutations have accumulated, implying the existence of long-lived, quiescent cell lineages capable of substantial proliferation upon acquisition of enabling genomic changes. Expansion of the dominant subclone to an appreciable mass may therefore represent the final rate-limiting step in a breast cancer's development, triggering diagnosis. PaperClip PMID:22608083

  17. Life history evolution in social insects: a female perspective.

    PubMed

    Negroni, Matteo Antoine; Jongepier, Evelien; Feldmeyer, Barbara; Kramer, Boris H; Foitzik, Susanne

    2016-08-01

    Social insects are known for their unusual life histories with fecund, long-lived queens and sterile, short-lived workers. We review ultimate factors underlying variation in life history strategies in female social insects, whose social life reshapes common trade-offs, such as the one between fecundity and longevity. Interspecific life history variation is associated with colony size, mediated by changes in division of labour and extrinsic mortality. In addition to the ratio of juvenile to adult mortality, social factors such as queen number influence life history trajectories. We discuss two hypotheses explaining why queen fecundity and lifespan is higher in single-queen societies and suggest further research directions on the evolution of life history variation in social insects.

  18. Competence and Quality in Real-Life Decision Making

    PubMed Central

    2015-01-01

    What distinguishes a competent decision maker and how should the issue of decision quality be approached in a real-life context? These questions were explored in three studies. In Study 1, using a web-based questionnaire and targeting a community sample, we investigated the relationships between objective and subjective indicators of real-life decision-making success. In Study 2 and 3, targeting two different samples of professionals, we explored if the prevalent cognitively oriented definition of decision-making competence could be beneficially expanded by adding aspects of competence in terms of social skills and time-approach. The predictive power for each of these three aspects of decision-making competence was explored for different indicators of real-life decision-making success. Overall, our results suggest that research on decision-making competence would benefit by expanding the definition of competence, by including decision-related abilities in terms of social skills and time-approach. Finally, the results also indicate that individual differences in real-life decision-making success profitably can be approached and measured by different criteria. PMID:26545239

  19. Guardianship and End-of-Life Decision Making

    PubMed Central

    Cohen, Andrew B.; Wright, Megan S.; Cooney, Leo; Fried, Terri

    2015-01-01

    As the population ages, more adults will develop impaired decision-making capacity and have no family members or friends available to make medical decisions on their behalf. In such situations, a professional guardian is often appointed by the court. This is an official who has no pre-existing relationship with the impaired individual but is paid to serve as a surrogate decision-maker. When a professional guardian is faced with decisions concerning life-sustaining treatment, substituted judgment may be impossible, and reports have repeatedly suggested that guardians are reluctant to make the decision to limit care. Clinicians are well positioned to assist guardians with these decisions and safeguard the rights of the vulnerable persons they represent. Doing so effectively requires knowledge of the laws governing end-of-life decisions by guardians. Clinicians, however, are often uncertain about whether guardians are empowered to withhold treatment and when their decisions require judicial review. To address this issue, we analyzed state guardianship statutes and reviewed recent legal cases in order to characterize the authority of a guardian over choices about end-of-life treatment. We found that a large majority of state guardianship statutes have no language about end-of-life decisions and identified just five legal cases over the past decade that addressed a guardian’s authority over these decisions, with only one case providing a broad framework applicable to clinical practice. Work to improve end-of-life decision-making by guardians may benefit from a multi-disciplinary effort to develop comprehensive standards that can guide clinicians and guardians when treatment decisions need to be made. PMID:26258634

  20. Inadvertent Exemplars: Life History Portraits of Two Socially Just Principals

    ERIC Educational Resources Information Center

    Scanlan, Martin

    2012-01-01

    This study creates life history portraits of two White middle-class native-English-speaking principals demonstrating commitments to social justice in their work in public elementary schools serving disproportionately high populations of students who are marginalized by poverty, race, and linguistic heritage. Through self-reported life histories of…

  1. Reflections on the Life Histories of Today's LGBQ Postsecondary Students

    ERIC Educational Resources Information Center

    Olive, James L.

    2012-01-01

    This qualitative multiple-case study utilized a life history methodology in which written and oral narratives were obtained from six postsecondary students who self-identified as lesbian, gay, bisexual, and/or queer (LGBQ). Through the construction of life histories, the researcher endeavored to understand how past experiences and behaviors shaped…

  2. Interrupting Life History: The Evolution of Relationship within Research

    ERIC Educational Resources Information Center

    Hallett, Ronald E.

    2013-01-01

    In this paper the author explores how relationships are defined within the context of constructing a life history. The life history of Benjamin, a homeless young man transitioning to adulthood, is used to illustrate how difficult it is to define the parameters of the research environment. During an "ethically important moment" in the…

  3. Reflections on the Life Histories of Today's LGBQ Postsecondary Students

    ERIC Educational Resources Information Center

    Olive, James L.

    2012-01-01

    This qualitative multiple-case study utilized a life history methodology in which written and oral narratives were obtained from six postsecondary students who self-identified as lesbian, gay, bisexual, and/or queer (LGBQ). Through the construction of life histories, the researcher endeavored to understand how past experiences and behaviors shaped…

  4. To Fairly Tell: Social Mobility, Life Histories, and the Anthropologist

    ERIC Educational Resources Information Center

    Benei, Veronique

    2010-01-01

    This article focuses on social agents' own understandings of socio-economic mobility and social achievement, exploring the possibilities offered by the tool of "family" life history in the context of formerly Untouchable communities in western India, Maharashtra. While arguing in favour of family life histories as both resource and…

  5. To Fairly Tell: Social Mobility, Life Histories, and the Anthropologist

    ERIC Educational Resources Information Center

    Benei, Veronique

    2010-01-01

    This article focuses on social agents' own understandings of socio-economic mobility and social achievement, exploring the possibilities offered by the tool of "family" life history in the context of formerly Untouchable communities in western India, Maharashtra. While arguing in favour of family life histories as both resource and…

  6. Inadvertent Exemplars: Life History Portraits of Two Socially Just Principals

    ERIC Educational Resources Information Center

    Scanlan, Martin

    2012-01-01

    This study creates life history portraits of two White middle-class native-English-speaking principals demonstrating commitments to social justice in their work in public elementary schools serving disproportionately high populations of students who are marginalized by poverty, race, and linguistic heritage. Through self-reported life histories of…

  7. Copepod life history traits in subtemperate regions

    NASA Astrophysics Data System (ADS)

    Ianora, Adrianna

    1998-06-01

    A review of the life history traits of subtemperate copepod genera indicates a number of common features. Most dominant species are continuous spawners with maximum levels of egg production reached at 15-20°C, depending on the species. Egg development times are quite rapid, about 24-72 h, within a temperature range of 15-30°C, and are largely temperature dependent. The potential fecundity seems to range widely among species; the most fecund species belong to the genera Centropages whereas the least fecund are those bearing egg sacs. The factors affecting production levels are both food quantity and food quality dependent but may also be regulated by metabolic processes that are in turn temperature dependent. Also potential egg viability seems to range widely during the year, from 0 to 60% in most cases, indicating that recruitment to the adult population may largely be controlled by physiological mortality rather than to predation or advective processes. There are probably several causes leading to reduced hatching success including an absence of remating, poor food conditions and/or the presence feeding deterrents such as the recently described inhibitory compounds blocking normal copepod embryogenesis. Another common feature of subtemperate species is that they show relatively constant development times from egg to adult, ranging generally from 18 to 25 d, depending on temperature and food conditions. Adult longevity then ranges from 2 to 3 months for adult females maintained in the laboratory which is much shorter than the 1 yr lifespan reported for north-temperate to boreal species.

  8. The Rhetoric of Right to Life: Beyond the Court's Decision.

    ERIC Educational Resources Information Center

    Solomon, Martha

    The Supreme Court's 1973 decision striking down restrictive abortion laws in Texas and Georgia has significantly shaped the rhetoric of the Right to Life movement in both tone and substance. This paper explores how the Court's decision has influenced the movement's definition and development of issues. In addition, it examines the verbal and…

  9. History of the Earth - The History of Life

    NASA Astrophysics Data System (ADS)

    Rozanov, A. Yu.

    2017-05-01

    To date there is more and more evidence that life is a phenomenon of galactic scale, and the problem of the life origin should be moved to an earlier time, at least 1-2 billion years from the usual dating. The process of life formation could begin already at the stage of the formation of solar clusters from molecular clouds, which leads us to consider the possible existence of an RNA world up to 7 billion years ago. Verification of physical conditions on the early Earth with the latest astrobiological and paleontological data shows that the optimal conditions for the existence of ancient bacteria suggest that the average temperature of the ocean is slightly higher than today. Also, thanks to the studies of the last two decades, the hypothesis of the oxygen-free atmosphere of the Earth in the first 2 billion years of its existence is rejected.

  10. The Digital Life History Project: Intergenerational Collaborative Research

    ERIC Educational Resources Information Center

    Loe, Meika

    2013-01-01

    This article describes the Digital Life History Project, a 10-week "lab" linked to a course on aging, in which students and community-dwelling elders work together to create a short digital story honoring the elder's life. After two interview sessions, the pair works together to produce a 3- to 5-minute digital life story narrated by the elder.…

  11. The Digital Life History Project: Intergenerational Collaborative Research

    ERIC Educational Resources Information Center

    Loe, Meika

    2013-01-01

    This article describes the Digital Life History Project, a 10-week "lab" linked to a course on aging, in which students and community-dwelling elders work together to create a short digital story honoring the elder's life. After two interview sessions, the pair works together to produce a 3- to 5-minute digital life story narrated by the elder.…

  12. A decision class analysis of critical care life-support decision-making.

    PubMed

    Seiver, A

    1993-02-01

    Decision analysis is a powerful methodology that can help clinicians make good decisions. Because it is not practical to place a decision analyst at the bedside in critical care units, the application of this methodology will require leveraging the analyst through computer-based systems. A decision class analysis is a collective analysis of a group of decisions that provides the high-level specification for such a computer system. This paper presents a decision class analysis of critical care life-support decisions. Key elements of this analysis are: the simplification of an otherwise extremely complex multistage sequential decision problem by using a sequence of two-stage models, and the use of six generic knowledge maps that capture the extremely complex relevant medical knowledge.

  13. Life cycle cost based program decisions

    NASA Technical Reports Server (NTRS)

    Dick, James S.

    1991-01-01

    The following subject areas are covered: background (space propulsion facility assessment team final report); changes (Advanced Launch System, National Aerospace Plane, and space exploration initiative); life cycle cost analysis rationale; and recommendation to panel.

  14. Narratives from within: An Arendtian Approach to Life Histories and the Writing of History

    ERIC Educational Resources Information Center

    Tamboukou, Maria

    2010-01-01

    In this paper I draw on my current research of writing a genealogy of women artists, focusing in particular on the life history of the American working-class artist, May Stevens (1924-). I am particularly interested in how an analysis of the textual and visual narratives in her work, seen in the context of her life history, can intervene in the…

  15. Narratives from within: An Arendtian Approach to Life Histories and the Writing of History

    ERIC Educational Resources Information Center

    Tamboukou, Maria

    2010-01-01

    In this paper I draw on my current research of writing a genealogy of women artists, focusing in particular on the life history of the American working-class artist, May Stevens (1924-). I am particularly interested in how an analysis of the textual and visual narratives in her work, seen in the context of her life history, can intervene in the…

  16. Competition and coexistence with multiple life-history stages.

    PubMed

    Moll, Jason D; Brown, Joel S

    2008-06-01

    Do complex life histories affect the conditions under which competitors can coexist? We investigated this using a two-species, two-stage Ricker model. With complex life cycles, the competition coefficients associated with each life-history stage suggest one of three competitive outcomes-coexistence, alternate stable states, or competitive exclusion-that depend on the relative magnitudes of intraspecific and interspecific competition. When the two stages suggest the same outcome, only that outcome can occur. When the stages suggest different outcomes, either one may prevail. It is also possible to have emergent outcomes, in which the outcome is not suggested by either stage. This can occur when the two stages suggest competitive exclusion by opposite species or when one stage suggests alternate stable states and the other suggests coexistence. Therefore, determining the mechanisms of coexistence in species with complex life histories may require consideration of competitive interactions within all life-history stages.

  17. Effects of age, size, and mating history on sex role decision of a simultaneous hermaphrodite.

    PubMed

    Nakadera, Yumi; Swart, Elferra M; Maas, Jeroen P A; Montagne-Wajer, Kora; Ter Maat, Andries; Koene, Joris M

    2015-01-01

    Contrasting with separate-sexed animals, simultaneous hermaphrodites display unique reproductive strategies as they are male and female at the same time. Simultaneous hermaphrodites that copulate unilaterally, for instance, make a decision to mate as a male or female. Previous studies have demonstrated that sex role preference in hermaphrodites is flexible and is controlled by several, often confounding, factors. We examined the relationship between sex role decisions and 3 life-history traits (age, size, and mating history) in the great pond snail, Lymnaea stagnalis. Based on our field observations, which indicate that adult individuals show overlapping generations and large variation in body size during the breeding season, we performed a sex role choice experiment in the laboratory. We found that young and small snails mate as males first. Both age and size significantly affected sex role decision, with age having a stronger effect. Furthermore, we tested whether L. stagnalis becomes reluctant to inseminate a mate after being inseminated because it is known that after insemination, male investment substantially reduces. Contrary to expectations, our results indicate that the receipt of seminal fluid does not seem to reduce male motivation. In sum, sex role decisions in L. stagnalis are largely determined by age and size but not by having received seminal fluid. This mating pattern, however, does not fully support the size-advantage model because large or old individuals did not perform better as females in our experiment. These results imply a conflicting mating interest, rather than harmonious agreement, between age- and size-different hermaphrodites.

  18. End of life decisions at the beginning of life.

    PubMed

    Snyder, R D

    1996-01-01

    Modern neonatal intensive care technology enhances the ability to maintain vulnerable newborns. In some circumstances survival may be insufficient justification for care. "End of life" strategies, originally applicable to adults, are being considered for newborns. Unresolved ethical issues in the care of these newborns involve multiple considerations. Concern occurs regarding patient-centered beneficence, non-maleficence, distributive justice, futility, legal rights of infants, and autonomy. The benefits to a newborn of treatment may fail to overcome the burdens of subsequent life. Under what circumstances a newborn loses the right to have life prolonged becomes a difficult ethical issue. With time and debate the proper response will become implemented.

  19. Shared decision making in Brazil: history and current discussion.

    PubMed

    Abreu, Mirhelen Mendes de; Battisti, Raphael; Martins, Rachel Samhan; Baumgratz, Thiago Dias; Cuziol, Mirella

    2011-01-01

    There is no SDM in clinical practice in Brazil. The first steps have been taken towards research and tool development recently. Likewise, our society is starting to get involved with decision making in health care. This paper aims to offer an overview of the Brazilian health system history, its values, and its influence on SDM. The participative social control concept is introduced as a result of the movement against the dictatorship era. In addition, the influence of social changes on the Medical Ethical Code is delineated. SDM state of the art in Brazil is also discussed and the challenges to implement it on clinical practice are described. Regardless the challenges, it is possible to make a positive assessment of SDM in Brazil.

  20. Improved viability of populations with diverse life-history portfolios

    PubMed Central

    Greene, Correigh M.; Hall, Jason E.; Guilbault, Kimberly R.; Quinn, Thomas P.

    2010-01-01

    A principle shared by both economists and ecologists is that a diversified portfolio spreads risk, but this idea has little empirical support in the field of population biology. We found that population growth rates (recruits per spawner) and life-history diversity as measured by variation in freshwater and ocean residency were negatively correlated across short time periods (one to two generations), but positively correlated at longer time periods, in nine Bristol Bay sockeye salmon populations. Further, the relationship between variation in growth rate and life-history diversity was consistently negative. These findings strongly suggest that life-history diversity can both increase production and buffer population fluctuations, particularly over long time periods. Our findings provide new insights into the importance of biocomplexity beyond spatio-temporal aspects of populations, and suggest that maintaining diverse life-history portfolios of populations may be crucial for their resilience to unfavourable conditions like habitat loss and climate change. PMID:20007162

  1. A database of life-history traits of European amphibians

    PubMed Central

    Moulherat, Sylvain; Calvez, Olivier; Stevens, Virginie M; Clobert, Jean; Schmeller, Dirk S

    2014-01-01

    Abstract In the current context of climate change and landscape fragmentation, efficient conservation strategies require the explicit consideration of life history traits. This is particularly true for amphibians, which are highly threatened worldwide, composed by more than 7400 species, which is constitute one of the most species-rich vertebrate groups. The collection of information on life history traits is difficult due to the ecology of species and remoteness of their habitats. It is therefore not surprising that our knowledge is limited, and missing information on certain life history traits are common for in this species group. We compiled data on amphibian life history traits from literature in an extensive database with morphological and behavioral traits, habitat preferences and movement abilities for 86 European amphibian species (50 Anuran and 36 Urodela species). When it were available, we reported data for males, females, juveniles and tadpoles. Our database may serve as an important starting point for further analyses regarding amphibian conservation. PMID:25425939

  2. Improved viability of populations with diverse life-history portfolios.

    PubMed

    Greene, Correigh M; Hall, Jason E; Guilbault, Kimberly R; Quinn, Thomas P

    2010-06-23

    A principle shared by both economists and ecologists is that a diversified portfolio spreads risk, but this idea has little empirical support in the field of population biology. We found that population growth rates (recruits per spawner) and life-history diversity as measured by variation in freshwater and ocean residency were negatively correlated across short time periods (one to two generations), but positively correlated at longer time periods, in nine Bristol Bay sockeye salmon populations. Further, the relationship between variation in growth rate and life-history diversity was consistently negative. These findings strongly suggest that life-history diversity can both increase production and buffer population fluctuations, particularly over long time periods. Our findings provide new insights into the importance of biocomplexity beyond spatio-temporal aspects of populations, and suggest that maintaining diverse life-history portfolios of populations may be crucial for their resilience to unfavourable conditions like habitat loss and climate change.

  3. Developing Pathways to Serving Together: Military Family Life Course and Decision-Making of Dual Military Couples

    DTIC Science & Technology

    2010-01-01

    Strategies.” Journal of Marriage and Family. 61:995-1007. Belli, Robert F. 1998. “The Structure of Autobiographical Memory and the Event History...with the interview by discussing factual events, priming the participants’ memory in the process of recall, and providing a sense of ownership in the...The life history calendar also serves as a memory aid in helping participants anchor their timing of decisions and puts them in a life course

  4. Exploring life history characteristics of naturalized versus stocked chinook

    USGS Publications Warehouse

    Rogers, Mark W.; Kerns, Janice A; Bunnell, David B.; Claramunt, Randall M.; Collingsworth, Paris D.

    2011-01-01

    Naturalization of stocked populations can result in divergence of life-history traits from domestic stocks. Lake Michigan supports popular Chinook (Oncorhynchus tshawytscha) Salmon fisheries that have been sustained by stocking since the late 1960s. Natural recruitment of Chinook Salmon in Lake Michigan has increased in the last few decades and currently contributes over 50% of Chinook Salmon recruits. Samples collected as part of a lakewide mass-marking of Lake Michigan Chinook Salmon, starting with the 2006 year class, indicated hatchery fish average 30-mm longer and 130 grams heavier than naturalized fish at age-1. We hypothesized that selective forces differ for naturalized and hatchery populations resulting in divergent life-history characteristics with implications for Chinook Salmon population production and the Lake Michigan fishery. Specific life-history metrics of interest include: age- and size- at maturity, spawning run timing, fecundity, and sex ratio. Objectives: We evaluated life history characteristics between naturally recruited and stocked Chinook Salmon in Lake Michigan to help discern potential changes resulting from naturalization and implications for fisheries. A. Conduct an analysis of historical data to determine if life-history parameters changed through time as the Chinook Salmon population became increasingly naturalized. B. Conduct a two-year field study of naturalized and hatchery stocked Chinook Salmon spawning populations to quantify differences in life-history metrics of adults. C. Determine if reproductive potential differs between naturalized and hatchery stocked Chinook salmon by measuring egg thiamine levels.

  5. Life history diversity and evolution in the Asterinidae.

    PubMed

    Byrne, Maria

    2006-06-01

    Asterinid sea stars have the greatest range of life histories known for the Asteroidea. Larval form in these sea stars has been modified in association with selection for planktonic, benthic, or intergonadal developmental habitats. Life history data are available for 31 species and molecular data for 28 of these. These data were used to assess life history evolution and relationships among asterinid clades. Lecithotrophy is prevalent in Asterinidae, with at least 6 independent origins of this developmental mode. Morphological differences in the attachment complex of brachiolaria larvae were evident among species with planktonic lecithotrophy. Some features are clade specific while others are variable within clades. Benthic brachiolariae are similar in Aquilonastra and Parvulastra with tripod-shaped larvae, while the bilobed sole-shaped larvae of Asterina species appear unique to this genus. Multiple transitions and pathways have been involved in the evolution of lecithotropy in the Asterinidae. Although several genera have a species with a planktonic feeding larva in a basal phylogenetic position, relative to species with planktonic or benthic lecithotrophy, there is little evidence for the expected life history transformation series from planktonic feeding, to planktonic non-feeding, to benthic non-feeding development. Intragonadal development, a life history pattern unique to the Asterinidae, arose three times through ancestors with benthic or pelagic lecithotrophy. Evolution of lecithotrophy appears more prevalent in the Asterinidae than other asteroid families. As diverse modes of development are discerned in cryptic species complexes, new insights into life history evolution in the Asterinidae are being generated.

  6. The effect of life expectancy on aggression and generativity: a life history perspective.

    PubMed

    Dunkel, Curtis S; Mathes, Eugene; Papini, Dennis R

    2010-09-23

    Following a model that is inclusive of both dispositional and situational influences on life-history behaviors and attitudes, the effect of life expectancies on aggression and generativity was examined. Consistent with the hypotheses it was found that shorter life expectancies led to an increase in the desire to aggress and a decrease in the desire to engage in generative behaviors. The results are discussed in terms of how life history theory can be used to frame research on person-situation interactions.

  7. [Palliative care - difficult decisions at the end of life].

    PubMed

    Kunz, Roland

    2009-08-01

    Palliative care comprises the complete treatment and care of patients suffering from incurable, life-threatening or chronically progressive disease. The aim is to provide the patients with the best possible quality of life and support them through the course of their illness until their death, to alleviate their suffering as much as possible and in consideration of the social, spiritual and religious aspects according to the patient's wishes. Palliative care is most important when the dying process and the patient's impending death do seem to be inevitable. Shared decision-making at an early stage of illness is mandatory. Respect for a person's dignity means focusing on their autonomy, their personal preferences and their right to live according to their own values and convictions. A person's autonomy is based on the level of information that he or she is given, the pertinent situation, and the patient's readiness and ability to take responsibility for their own life and end-of-life decisions. Decisions about life-prolonging measures, treatment of pain, dyspnea and palliative sedation require balancing the burden against the benefits. Decision-making must rest with the patient - as far as possible and as long as possible. The potential life-shortening effect of palliative therapy will need to be considered and discussed.

  8. End-of-life treatment decision making: American Indians' perspective.

    PubMed

    Colclough, Yoshiko Yamashita; Brown, Gary M

    2014-08-01

    This study explored American Indians' end-of-life experiences in treatment decision making. Scarce knowledge about this population's perspective regarding end-of-life treatments has resulted in health care providers (HCPs) functioning at less than optimum levels. Using a community-based participatory research approach, open-ended interview data were collected and analyzed using a grounded theory method. Patient and family participants generally stated that the physicians made the treatment decisions for them, while HCPs believed that patients participated in informed autonomous treatment decision making. Both parties (HCPs and patients and families) were not aware of American Indian's psychological aspect that interfered with the exercise of the right of informed consent. This additional understanding would benefit them in order to result in ethically and legally sound practice of patient's autonomous treatment decision making. © The Author(s) 2013.

  9. Accuracy of a decision aid for advance care planning: simulated end-of-life decision making.

    PubMed

    Levi, Benjamin H; Heverley, Steven R; Green, Michael J

    2011-01-01

    Advance directives have been criticized for failing to help physicians make decisions consistent with patients' wishes. This pilot study sought to determine if an interactive, computer-based decision aid that generates an advance directive can help physicians accurately translate patients' wishes into treatment decisions. We recruited 19 patient-participants who had each previously created an advance directive using a computer-based decision aid, and 14 physicians who had no prior knowledge of the patient-participants. For each advance directive, three physicians were randomly assigned to review the advance directive and make five to six treatment decisions for each of six (potentially) end-of-life clinical scenarios. From the three individual physicians' responses, a "consensus physician response" was generated for each treatment decision (total decisions = 32). This consensus response was shared with the patient whose advance directive had been reviewed, and she/he was then asked to indicate how well the physician translated his/her wishes into clinical decisions. Patient-participants agreed with the consensus physician responses 84 percent (508/608) of the time, including 82 percent agreement on whether to provide mechanical ventilation, and 75 percent on decisions about cardiopulmonary resuscitation (CPR). Across the six vignettes, patient-participants' rating of how well physicians translated their advance directive into medical decisions was 8.4 (range = 6.5-10, where 1 = extremely poorly, and 10 = extremely well). Physicians' overall rating of their confidence at accurately translating patients' wishes into clinical decisions was 7.8 (range = 6.1-9.3, 1 = not at all confident, 10 = extremely confident). For simulated cases, a computer-based decision aid for advance care planning can help physicians more confidently make end-of-life decisions that patients will endorse.

  10. The history of ethical decision making in neonatal intensive care.

    PubMed

    Placencia, Frank X; McCullough, Laurence B

    2011-01-01

    Neonatal ethics has focused on 2 questions: is withholding potentially live-saving treatment from neonates ethically justified? and if so, who has the authority to decide? This article details how these questions developed and provides a description of the possible answers. In the first section, we review a selection of seminal articles by noted authors in the fields of ethics, medicine, and law. The second section provides a detailed account of the development of the Baby Doe Regulations and the impact they had on neonatal ethics, with particular attention to the emergence of the Best Interest Standard as a guideline for decision making. In the last section, we review the landmark position statements by the American Academy of Pediatric (AAP), and the focus on evidence-based decision making. We conclude that forgoing life-saving treatment is ethically justified. However, this requires a rigorous evidence-based process and is limited by the Best Interest Standard. The second question is more difficult to answer, but we feel that in light of legal limitations, physicians acting as both the infant advocate and a proxy for the state, decide what falls in the range of acceptable treatment options, with the parents free to choose within that range.

  11. Impact of Life History on Fear Memory and Extinction

    PubMed Central

    Remmes, Jasmin; Bodden, Carina; Richter, S. Helene; Lesting, Jörg; Sachser, Norbert; Pape, Hans-Christian; Seidenbecher, Thomas

    2016-01-01

    Behavioral profiles are strongly shaped by an individual's whole life experience. The accumulation of negative experiences over lifetime is thought to promote anxiety-like behavior in adulthood (“allostatic load hypothesis”). In contrast, the “mismatch hypothesis” of psychiatric disease suggests that high levels of anxiety-like behavior are the result of a discrepancy between early and late environment. The aim of the present study was to investigate how different life histories shape the expression of anxiety-like behavior and modulate fear memory. In addition, we aimed to clarify which of the two hypotheses can better explain the modulation of anxiety and fear. For this purpose, male mice grew up under either adverse or beneficial conditions during early phase of life. In adulthood they were further subdivided in groups that either matched or mismatched the condition experienced before, resulting in four different life histories. The main results were: (i) Early life benefit followed by late life adversity caused decreased levels of anxiety-like behavior. (ii) Accumulation of adversity throughout life history led to impaired fear extinction learning. Late life adversity as compared to late life benefit mainly affected extinction training, while early life adversity as compared to early life benefit interfered with extinction recall. Concerning anxiety-like behavior, the results do neither support the allostatic load nor the mismatch hypothesis, but rather indicate an anxiolytic effect of a mismatched early beneficial and later adverse life history. In contrast, fear memory was strongly affected by the accumulation of adverse experiences over the lifetime, therefore supporting allostatic load hypothesis. In summary, this study highlights that anxiety-like behavior and fear memory are differently affected by specific combinations of adverse or beneficial events experienced throughout life. PMID:27757077

  12. Seedling architecture and life history evolution in pines

    Treesearch

    Steven H. Strauss; F. Thomas Ledig

    1985-01-01

    Much of the work on life history evolution in plants has dealt with allocation of reproductive effort (Abrahamson 1975; Abrahamson and Gadgil 1973; Gaines et al. 1974; McNaughton 1975; Oka 1976; Stearns 1976, 1977, 1980; Newell and Tramer 1978; Primack 1979). The juvenile period, however, occupies a major and critical portion of the life cycle of many species....

  13. Seedling architechture and life history evolution in pines

    Treesearch

    Steven H. Strauss; F. Thomas Ledig

    1985-01-01

    Much of the work on life history evolution in plants has dealt with allocation of reproductive effort (Abrahamson 1975; Abrahamson and Gadgil 1973; Gaines et al. 1974; McNaughton 1975; Oka 1976; Stearns 1976, 1977, 1980; Newel1 and Tramer 1978; Primack 1979). The juvenile period, however, occupies a major and critical portion of the life cycle of many species....

  14. Hyperthermophiles in the history of life

    PubMed Central

    Stetter, Karl O

    2006-01-01

    Today, hyperthermophilic (‘superheat-loving’) bacteria and archaea are found within high-temperature environments, representing the upper temperature border of life. They grow optimally above 80°C and exhibit an upper temperature border of growth up to 113°C. Members of the genera, Pyrodictium and Pyrolobus, survive at least 1 h of autoclaving. In their basically anaerobic environments, hyperthermophiles (HT) gain energy by inorganic redox reactions employing compounds like molecular hydrogen, carbon dioxide, sulphur and ferric and ferrous iron. Based on their growth requirements, HT could have existed already on the early Earth about 3.9 Gyr ago. In agreement, within the phylogenetic tree of life, they occupy all the short deep branches closest to the root. The earliest archaeal phylogenetic lineage is represented by the extremely tiny members of the novel kingdom of Nanoarchaeota, which thrive in submarine hot vents. HT are very tough survivors, even in deep-freezing at −140°C. Therefore, during impact ejecta, they could have been successfully transferred to other planets and moons through the coldness of space. PMID:17008222

  15. Roma Women's Perspectives on End-of-Life Decisions.

    PubMed

    Peinado-Gorlat, Patricia; Castro-Martínez, Francisco Javier; Arriba-Marcos, Beatriz; Melguizo-Jiménez, Miguel; Barrio-Cantalejo, Inés

    2015-12-01

    Spain's Roma community has its own cultural and moral values. These values influence the way in which end-of-life decision-making is confronted. The objective of this study was to explore the perspective of Roma women on end-of-life decision-making. It was a qualitative study involving thirty-three Roma women belonging to groups for training and social development in two municipalities. We brought together five focus groups between February and December 2012. Six mediators each recruited five to six participants. We considered age and care role to be the variables that can have the most influence on opinion regarding end-of-life decision-making. We considered the discussion saturated when the ideas expressed were repeated. Data analysis was carried out according to five steps: describing, organizing, connecting, corroborating/legitimating, and representing the account. The main ideas gleaned from the data were as follows: (1) the important role of the family in end-of-life care, especially the role of women; (2) the large influence of community opinion over personal or family decisions, typical of closed societies; (3) the different preferences women had for themselves compared to that for others regarding desired end-of-life care; (4) unawareness or rejection of advance directives. Roma women wish for their healthcare preferences to be taken into account, but "not in writing." The study concluded that the success of end-of-life healthcare in Roma families and of their involvement in the making of healthcare decisions depends upon considering and respecting their idiosyncrasy.

  16. Dyadic fertility decisions in a life course perspective.

    PubMed

    Bauer, Gerrit; Kneip, Thorsten

    2014-09-01

    This paper focuses on how couples arrive at joint decisions with regard to fertility behaviour. We build upon previous work on decision rules that couples might apply as heuristics in order to arrive at joint action in cases in which partners' fertility preferences differ. Previous research found either stronger effects of women's desires or symmetrical effects of both spouses' desires and net benefits associated with (further) children on proceptive behaviour. The latter finding is in line with the notion of household utility maximisation, in which both partners' preferences enter into a joint utility function with equal weight. On the other hand, some evidence indicates that one partner can exercise a 'veto' if he or she anticipates individual utility losses from a further child (due to opportunity costs arising in other life domains). We now enhance previous research by applying a life-course perspective. Our analysis makes use of variation in initial conditions due to previous births: couples decide on fertility in different situations as they find themselves in different life course stages and have had certain experiences. Parity-specific differences affect not only fertility outcomes but also the decision-making process itself. Our findings show that the decision to have a first child is made jointly, and each partner may exercise a veto. On the other hand, women appear to dominate decisions on higher parity births, not per se, but because they are (still) the ones more affected by the concomitant housework.

  17. Life-History Patterns of Lizards of the World.

    PubMed

    Mesquita, Daniel O; Costa, Gabriel C; Colli, Guarino R; Costa, Taís B; Shepard, Donald B; Vitt, Laurie J; Pianka, Eric R

    2016-06-01

    Identification of mechanisms that promote variation in life-history traits is critical to understand the evolution of divergent reproductive strategies. Here we compiled a large life-history data set (674 lizard populations, representing 297 species from 263 sites globally) to test a number of hypotheses regarding the evolution of life-history traits in lizards. We found significant phylogenetic signal in most life-history traits, although phylogenetic signal was not particularly high. Climatic variables influenced the evolution of many traits, with clutch frequency being positively related to precipitation and clutches of tropical lizards being smaller than those of temperate species. This result supports the hypothesis that in tropical and less seasonal climates, many lizards tend to reproduce repeatedly throughout the season, producing smaller clutches during each reproductive episode. Our analysis also supported the hypothesis that viviparity has evolved in lizards as a response to cooler climates. Finally, we also found that variation in trait values explained by clade membership is unevenly distributed among lizard clades, with basal clades and a few younger clades showing the most variation. Our global analyses are largely consistent with life-history theory and previous results based on smaller and scattered data sets, suggesting that these patterns are remarkably consistent across geographic and taxonomic scales.

  18. Life history evolution and comparative developmental biology of echinoderms.

    PubMed

    Hart, Michael W

    2002-01-01

    Evolutionary biologists studying life history variation have used echinoderms in experimental, laboratory, and field studies of life history evolution. This focus on echinoderms grew originally from the tradition of comparative embryology, in which echinoderms were central. The tools for obtaining and manipulating echinoderm gametes and larvae were taken directly from comparative embryological research. In addition, the comparative embryologists employed a diverse array of echinoderms, not a few model species, and this diversity has led to a broad understanding of the development, function, and evolution of echinoderm larvae. As a result, this branch of life history evolution has deep roots in comparative developmental biology of echinoderms. Here two main aspects of this relationship are reviewed. The first is a broad range of studies of fertilization biology, dispersal, population genetics, functional morphology, and asexual reproduction in which developmental biologists might take a keen interest because of the historical origins of this research in echinoderm comparative embryology. The second is a similarly broad variety of topics in life history research in which evolutionary biologists require techniques or data from developmental biology in order to make progress on understanding patterns of life history variation among echinoderm species and higher taxa. Both sets of topics provide opportunities for interaction and collaboration.

  19. Life histories predict coral community disassembly under multiple stressors.

    PubMed

    Darling, Emily S; McClanahan, Timothy R; Côté, Isabelle M

    2013-06-01

    Climate change is reshaping biological communities against a background of existing human pressure. Evaluating the impacts of multiple stressors on community dynamics can be particularly challenging in species-rich ecosystems, such as coral reefs. Here, we investigate whether life-history strategies and cotolerance to different stressors can predict community responses to fishing and temperature-driven bleaching using a 20-year time series of coral assemblages in Kenya. We found that the initial life-history composition of coral taxa largely determined the impacts of bleaching and coral loss. Prior to the 1998 bleaching event, coral assemblages within no-take marine reserves were composed of three distinct life histories - competitive, stress-tolerant and weedy- and exhibited strong declines following bleaching with limited subsequent recovery. In contrast, fished reefs had lower coral cover, fewer genera and were composed of stress-tolerant and weedy corals that were less affected by bleaching over the long term. Despite these general patterns, we found limited evidence for cotolerance as coral genera and life histories were variable in their sensitivities to fishing and bleaching. Overall, fishing and bleaching have reduced coral diversity and led to altered coral communities of 'survivor' species with stress-tolerant and weedy life histories. Our findings are consistent with expectations that climate change interacting with existing human pressure will result in the loss of coral diversity and critical reef habitat. © 2013 Blackwell Publishing Ltd.

  20. End-of-life decision-making in India.

    PubMed

    Freckelton, Ian

    2014-09-01

    The extraordinary circumstances and the tragic life of Aruna Shanbaug, together with the landmark Supreme Court of India decision in Shanbaug v Union of India (2011) 4 SCC 454, have provided a fillip and focus to debate within India about end-of-life decision-making. This extends to passive euthanasia, decision-making about withdrawal of nutrition, hydration and medical treatment from persons in a permanent vegetative or quasi-vegetative state, the role of the courts in such matters, the risks of corruption and misconduct, the criminal status of attempted suicide, and even the contentious issue of physician-assisted active euthanasia. The debates have been promoted further by important reports of the Law Commission of India. This editorial reviews the current state of the law and debate about such issues in India.

  1. The Crowded Life Is a Slow Life: Population Density and Life History Strategy.

    PubMed

    Sng, Oliver; Neuberg, Steven L; Varnum, Michael E W; Kenrick, Douglas T

    2017-01-09

    The world population has doubled over the last half century. Yet, research on the psychological effects of human population density, once a popular topic, has decreased over the past few decades. Applying a fresh perspective to an old topic, we draw upon life history theory to examine the effects of population density. Across nations and across the U.S. states (Studies 1 and 2), we find that dense populations exhibit behaviors corresponding to a slower life history strategy, including greater future-orientation, greater investment in education, more long-term mating orientation, later marriage age, lower fertility, and greater parental investment. In Studies 3 and 4, experimentally manipulating perceptions of high density led individuals to become more future-oriented. Finally, in Studies 5 and 6, experimentally manipulating perceptions of high density seemed to lead to life-stage-specific slower strategies, with college students preferring to invest in fewer rather than more relationship partners, and an older MTurk sample preferring to invest in fewer rather than more children. This research sheds new insight on the effects of density and its implications for human cultural variation and society at large. (PsycINFO Database Record

  2. Life history of amphibians and gravity.

    PubMed

    Naitoh, Tomio; Yamashita, Masamichi; Wassersug, Richard J

    2004-11-01

    Anurans hold a unique position in vertebrate phylogeny, as they made the major transition from water to land. Through evolution they have acquired fundamental mechanisms to adapt to terrestrial gravity. Such mechanisms are now shared among other terrestrial vertebrates derived from ancestral amphibians. Space research, using amphibians as a model animal, is significant based on the following aspects: (1) Anuran amphibians show drastic changes in their living niche during their metamorphosis. Environments for tadpoles and for terrestrial life of frogs are quite different in terms of gravity and its associated factors. (2) Certain tadpoles, such as Rhacophorus viridis amamiensis, have a transparent abdominal wall. Thus visceral organs and their motion can be observed in these animals in non-invasive manner through their transparent abdominal skin. This feature enables biologists to evaluate the physiological state of these amphibians and study the autonomic control of visceral organs. It is also feasible for space biologists to examine how such autonomic regulation could be altered by microgravity and exposure to the space environment.

  3. Influence of physicians' life stances on attitudes to end-of-life decisions and actual end-of-life decision-making in six countries.

    PubMed

    Cohen, J; van Delden, J; Mortier, F; Löfmark, R; Norup, M; Cartwright, C; Faisst, K; Canova, C; Onwuteaka-Philipsen, B; Bilsen, J

    2008-04-01

    To examine how physicians' life stances affect their attitudes to end-of-life decisions and their actual end-of-life decision-making. Practising physicians from various specialties involved in the care of dying patients in Belgium, Denmark, The Netherlands, Sweden, Switzerland and Australia received structured questionnaires on end-of-life care, which included questions about their life stance. Response rates ranged from 53% in Australia to 68% in Denmark. General attitudes, intended behaviour with respect to two hypothetical patients, and actual behaviour were compared between all large life-stance groups in each country. Only small differences in life stance were found in all countries in general attitudes and intended and actual behaviour with regard to various end-of-life decisions. However, with regard to the administration of drugs explicitly intended to hasten the patient's death (PAD), physicians with specific religious affiliations had significantly less accepting attitudes, and less willingness to perform it, than non-religious physicians. They had also actually performed PAD less often. However, in most countries, both Catholics (up to 15.7% in The Netherlands) and Protestants (up to 20.4% in The Netherlands) reported ever having made such a decision. The results suggest that religious teachings influence to some extent end-of-life decision-making, but are certainly not blankly accepted by physicians, especially when dealing with real patients and circumstances. Physicians seem to embrace religious belief in a non-imperative way, allowing adaptation to particular situations.

  4. Life history theory predicts fish assemblage response to hydrologic regimes.

    PubMed

    Mims, Meryl C; Olden, Julian D

    2012-01-01

    The hydrologic regime is regarded as the primary driver of freshwater ecosystems, structuring the physical habitat template, providing connectivity, framing biotic interactions, and ultimately selecting for specific life histories of aquatic organisms. In the present study, we tested ecological theory predicting directional relationships between major dimensions of the flow regime and life history composition of fish assemblages in perennial free-flowing rivers throughout the continental United States. Using long-term discharge records and fish trait and survey data for 109 stream locations, we found that 11 out of 18 relationships (61%) tested between the three life history strategies (opportunistic, periodic, and equilibrium) and six hydrologic metrics (two each describing flow variability, predictability, and seasonality) were statistically significant (P < or = 0.05) according to quantile regression. Our results largely support a priori hypotheses of relationships between specific flow indices and relative prevalence of fish life history strategies, with 82% of all significant relationships observed supporting predictions from life history theory. Specifically, we found that (1) opportunistic strategists were positively related to measures of flow variability and negatively related to predictability and seasonality, (2) periodic strategists were positively related to high flow seasonality and negatively related to variability, and (3) the equilibrium strategists were negatively related to flow variability and positively related to predictability. Our study provides important empirical evidence illustrating the value of using life history theory to understand both the patterns and processes by which fish assemblage structure is shaped by adaptation to natural regimes of variability, predictability, and seasonality of critical flow events over broad biogeographic scales.

  5. A life history model of the alcoholic family.

    PubMed

    Steinglass, P

    1980-09-01

    Research and clinical interest in the alcoholic family has tended to outpace the development of family-oriented conceptual models of alcoholism. A family development perspective has been almost totally absent, despite the chronic, longitudinal nature of alcoholism. A life history model is proposed that uses the concepts of the "alcoholic system," family homeostasis, and the "family alcohol phase" as its building blocks. Chronic alcoholism tends to produce distortions in the normative family life cycle. These distortions and their clinical implications are discussed, using four case histories as illustrations of the concepts proposed. The model is also examined in the light of current research findings about the alcoholic family.

  6. Developmental plasticity in the life history of a prosauropod dinosaur.

    PubMed

    Sander, P Martin; Klein, Nicole

    2005-12-16

    Long-bone histology indicates that the most common early dinosaur, the prosauropod Plateosaurus engelhardti from the Upper Triassic of Central Europe, had variable life histories. Although Plateosaurus grew at the fast rates typical for dinosaurs, as indicated by fibrolamellar bone, qualitative (growth stop) and quantitative (growth-mark counts) features of its histology are poorly correlated with body size. Individual life histories of P. engelhardti were influenced by environmental factors, as in modern ectothermic reptiles, but not in mammals, birds, or other dinosaurs.

  7. Effects of age, size, and mating history on sex role decision of a simultaneous hermaphrodite

    PubMed Central

    Swart, Elferra M.; Maas, Jeroen P.A.; Montagne-Wajer, Kora; Ter Maat, Andries; Koene, Joris M.

    2015-01-01

    Contrasting with separate-sexed animals, simultaneous hermaphrodites display unique reproductive strategies as they are male and female at the same time. Simultaneous hermaphrodites that copulate unilaterally, for instance, make a decision to mate as a male or female. Previous studies have demonstrated that sex role preference in hermaphrodites is flexible and is controlled by several, often confounding, factors. We examined the relationship between sex role decisions and 3 life-history traits (age, size, and mating history) in the great pond snail, Lymnaea stagnalis. Based on our field observations, which indicate that adult individuals show overlapping generations and large variation in body size during the breeding season, we performed a sex role choice experiment in the laboratory. We found that young and small snails mate as males first. Both age and size significantly affected sex role decision, with age having a stronger effect. Furthermore, we tested whether L. stagnalis becomes reluctant to inseminate a mate after being inseminated because it is known that after insemination, male investment substantially reduces. Contrary to expectations, our results indicate that the receipt of seminal fluid does not seem to reduce male motivation. In sum, sex role decisions in L. stagnalis are largely determined by age and size but not by having received seminal fluid. This mating pattern, however, does not fully support the size-advantage model because large or old individuals did not perform better as females in our experiment. These results imply a conflicting mating interest, rather than harmonious agreement, between age- and size-different hermaphrodites. PMID:25713474

  8. Unravelling the life history of Amazonian fishes through otolith microchemistry.

    PubMed

    Hermann, Theodore W; Stewart, Donald J; Limburg, Karin E; Castello, Leandro

    2016-06-01

    Amazonian fishes employ diverse migratory strategies, but the details of these behaviours remain poorly studied despite numerous environmental threats and heavy commercial exploitation of many species. Otolith microchemistry offers a practical, cost-effective means of studying fish life history in such a system. This study employed a multi-method, multi-elemental approach to elucidate the migrations of five Amazonian fishes: two 'sedentary' species (Arapaima sp. and Plagioscion squamosissimus), one 'floodplain migrant' (Prochilodus nigricans) and two long-distance migratory catfishes (Brachyplatystoma rousseauxii and B. filamentosum). The Sr : Ca and Zn : Ca patterns in Arapaima were consistent with its previously observed sedentary life history, whereas Sr : Ca and Mn : Ca indicated that Plagioscion may migrate among multiple, chemically distinct environments during different life-history stages. Mn : Ca was found to be potentially useful as a marker for identifying Prochilodus's transition from its nursery habitats into black water. Sr : Ca and Ba : Ca suggested that B. rousseauxii resided in the Amazon estuary for the first 1.5-2 years of life, shown by the simultaneous increase/decrease of otolith Sr : Ca/Ba : Ca, respectively. Our results further suggested that B. filamentosum did not enter the estuary during its life history. These results introduce what should be a productive line of research desperately needed to better understand the migrations of these unique and imperilled fishes.

  9. Implications of life-history strategies for obesity.

    PubMed

    Maner, Jon K; Dittmann, Andrea; Meltzer, Andrea L; McNulty, James K

    2017-08-08

    The association between low socioeconomic status (SES) and obesity is well documented. In the current research, a life history theory (LHT) framework provided an explanation for this association. Derived from evolutionary behavioral science, LHT emphasizes how variability in exposure to unpredictability during childhood gives rise to individual differences in a range of social psychological processes across the life course. Consistent with previous LHT research, the current findings suggest that exposure to unpredictability during childhood (a characteristic common to low SES environments) is associated with the adoption of a fast life-history strategy, one marked by impulsivity and a focus on short-term goals. We demonstrate that a fast life-history strategy, in turn, was associated with dysregulated weight-management behaviors (i.e., eating even in the absence of hunger), which were predictive of having a high body mass index (BMI) and being obese. In both studies, findings held while controlling for participants' current socioeconomic status, suggesting that obesity is rooted in childhood experiences. A serial mediation model in study 2 confirmed that effects of childhood SES on adult BMI and obesity can be explained in part by exposure to unpredictability, the adoption of a fast life-history strategy, and dysregulated-eating behaviors. These findings suggest that weight problems in adulthood may be rooted partially in early childhood exposure to unpredictable events and environments. LHT provides a valuable explanatory framework for understanding the root causes of obesity.

  10. Major Life Decisions of Gifted Adults in Relation to Overall Life Satisfaction

    ERIC Educational Resources Information Center

    Perrone-McGovern, Kristin M.; Ksiazak, Tracy M.; Wright, Stephen L.; Vannatter, Aarika; Hyatt, Claudine C.; Shepler, Dustin; Perrone, Philip A.

    2011-01-01

    In this study, major life decisions of gifted adults were examined in relation to life satisfaction. Participants were 57 gifted adults who have been participating in a longitudinal study over the last two decades. Qualitative data were collected via written and online surveys, and were analyzed by a research team using phenomenological,…

  11. Planetary Biology-Paleontological, Geological, and Molecular Histories of Life

    NASA Astrophysics Data System (ADS)

    Benner, Steven A.; Caraco, M. Daniel; Thomson, J. Michael; Gaucher, Eric A.

    2002-05-01

    The history of life on Earth is chronicled in the geological strata, the fossil record, and the genomes of contemporary organisms. When examined together, these records help identify metabolic and regulatory pathways, annotate protein sequences, and identify animal models to develop new drugs, among other features of scientific and biomedical interest. Together, planetary analysis of genome and proteome databases is providing an enhanced understanding of how life interacts with the biosphere and adapts to global change.

  12. Planetary biology--paleontological, geological, and molecular histories of life.

    PubMed

    Benner, Steven A; Caraco, M Daniel; Thomson, J Michael; Gaucher, Eric A

    2002-05-03

    The history of life on Earth is chronicled in the geological strata, the fossil record, and the genomes of contemporary organisms. When examined together, these records help identify metabolic and regulatory pathways, annotate protein sequences, and identify animal models to develop new drugs, among other features of scientific and biomedical interest. Together, planetary analysis of genome and proteome databases is providing an enhanced understanding of how life interacts with the biosphere and adapts to global change.

  13. Discussing Life-sustaining Therapy With Surrogate Decision Makers.

    PubMed

    Hwang, David Y

    2017-02-01

    Clinicians caring for patients with severe stroke in intensive care units often grapple with requests from surrogate decision makers for life-prolonging treatment that members of the care team may believe to be futile. An example is a surrogate decision maker's request to place a tracheostomy and feeding tube in a patient who, in the clinical judgment of the neurocritical care team, is very unlikely to recover interactive capacity. This article presents a case, discusses definitions of medical futility, and summarizes recommended steps for mediating conflict regarding potentially inappropriate treatment.

  14. Caring Decisions: The Development of a Written Resource for Parents Facing End-of-Life Decisions.

    PubMed

    Xafis, Vicki; Gillam, Lynn; Hynson, Jenny; Sullivan, Jane; Cossich, Mary; Wilkinson, Dominic

    2015-11-01

    Written resources in adult intensive care have been shown to benefit families facing end of life (EoL) decisions. There are few resources for parents making EoL decisions for their child and no existing resources addressing ethical issues. The Caring Decisions handbook and website were developed to fill these gaps. We discuss the development of the resources, modification after reviewer feedback and findings from initial pilot implementation. A targeted literature review-to identify resources and factors that impact on parental EoL decision-making; development phase-guided by the literature and the researchers' expertise; consultation process-comprised a multi-disciplinary panel of experts and parents; pilot evaluation study-hard-copy handbook was distributed as part of routine care at an Australian Children's Hospital. Twelve experts and parents formed the consultation panel. Eight parents of children with life-limiting conditions and clinicians were interviewed in the pilot study. Numerous factors supporting/impeding EoL decisions were identified. Caring Decisions addressed issues identified in the literature and by the multidisciplinary research team. The consultation panel provided overwhelmingly positive feedback. Pilot study parents found the resources helpful and comforting. Most clinicians viewed the resources as very beneficial to parents and identified them as ideal for training purposes. The development of the resources addressed many of the gaps in existing resources. The consultation process and the pilot study suggest these resources could be of significant benefit to parents and clinicians.

  15. Life-history evolution in ants: the case of Cardiocondyla

    PubMed Central

    2017-01-01

    Ants are important components of most terrestrial habitats, and a better knowledge of the diversity of their life histories is essential to understand many aspects of ecosystem functioning. The myrmicine genus Cardiocondyla shows a wide range of colony structures, reproductive behaviours, queen and male lifespans, and habitat use. Reconstructing the evolutionary pathways of individual and social phenotypic traits suggests that the ancestral life history of Cardiocondyla was characterized by the presence of multiple, short-lived queens in small-sized colonies and a male polyphenism with winged dispersers and wingless fighters, which engage in lethal combat over female sexuals within their natal nests. Single queening, queen polyphenism, the loss of winged males and tolerance among wingless males appear to be derived traits that evolved with changes in nesting habits, colony size and the spread from tropical to seasonal environments. The aim of this review is to bring together the information on life-history evolution in Cardiocondyla and to highlight the suitability of this genus for functional genomic studies of adaptation, phenotypic plasticity, senescence, invasiveness and other key life-history traits of ants. PMID:28298341

  16. Life History Influences on Holland Vocational Type Development.

    ERIC Educational Resources Information Center

    Smart, John C.

    1989-01-01

    Examined relative influence of selected life history experiences on development of three vocational types proposed by Holland. Data from employees classified as Investigative (n=490), Social (N=1,421), and Enterprising (N=707) support Holland's premise that vocational type development is function of complex series of events resulting from family…

  17. Significant effects of fishing gear selectivity on fish life history

    NASA Astrophysics Data System (ADS)

    Liang, Zhenlin; Sun, Peng; Yan, Wei; Huang, Liuyi; Tang, Yanli

    2014-06-01

    Over the past few decades, extreme changes have occurred in the characters of exploited fish populations. The majority of these changes have affected the growth traits of fish life history, which include a smaller size-at-age, an earlier age-at-maturation and among others. Currently, the causes of these life history traits changes still require systematic analyses and empirical studies. The explanations that have been cited are merely expressed in terms of fish phenotypic adaptation. It has been claimed that the original traits of fish can be recovered once the intensity of exploitation of the fish is controlled. Sustained environmental and fishing pressure will change the life history traits of most fish species, so the fish individual's traits are still in small size-at-age and at earlier age-at-maturation in exploited fish populations. In this paper, we expressed our view of points that fishing gear has imposed selectivity on fish populations and individuals as various other environmental factors have done and such changes are unrecoverable. According to the existing tend of exploited fish individual's life history traits, we suggested further researches in this field and provided better methods of fishery management and thereby fishery resources protection than those available early.

  18. Patterns in life history traits of deep-water chondrichthyans

    NASA Astrophysics Data System (ADS)

    Rigby, Cassandra; Simpfendorfer, Colin A.

    2015-05-01

    Life history traits are important indicators of the productivity of species, and their ability to tolerate fishing pressure. Using a variety of life history traits (maximum size, size and age at maturity, longevity, growth rate, litter and birth size) we demonstrated differences in chondrichthyan life histories between shelf, pelagic and deep-water habitats and within the deep habitat down the continental slope and across geographic regions. Deep-water species had lower growth rates, later age at maturity, and higher longevity than both shelf and pelagic species. In the deep habitat, with increasing depth, species matured later, lived longer, had smaller litters and bred less frequently; regional differences in traits were also apparent. Deep-water species also had a smaller body size and the invariants of relative size and age at maturity were higher in deep water. The visual interaction hypothesis offers a potential explanation for these findings and it is apparent habitat influences the trade-offs in allocation of energy for survival and reproduction. Body size is not appropriate as a predictor of vulnerability in deep-water chondrichthyans and regional trait differences are possibly due to a fishing pressure response. Deep-water chondrichthyans are more vulnerable to exploitation than shelf and pelagic species and this vulnerability markedly increases with increasing depth. The life history traits of deep-water chondrichthyans are unique and reflect adaptations driven by both mortality and resource limitations of their habitat.

  19. Life Histories of Three Exemplary American Physical Educators

    ERIC Educational Resources Information Center

    Cazers, Gunars

    2009-01-01

    The purpose of the following article-style dissertation was to present the life histories of three exemplary physical educators, to give them voice, explore ways in which they experienced marginalization, and describe how they persevered in spite of difficulties they experienced in their careers. The participants included (a) Robin, a female…

  20. Life-history evolution: at the origins of metamorphosis.

    PubMed

    Holstein, Thomas W; Laudet, Vincent

    2014-02-17

    Metamorphosis is a widespread life history strategy of animals but apart from some model organisms it is poorly characterized. A recent study of moon jellies highlights the similarities and differences between the various types of metamorphosis and illuminates its molecular determinants. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Life Histories of Three Exemplary American Physical Educators

    ERIC Educational Resources Information Center

    Cazers, Gunars

    2009-01-01

    The purpose of the following article-style dissertation was to present the life histories of three exemplary physical educators, to give them voice, explore ways in which they experienced marginalization, and describe how they persevered in spite of difficulties they experienced in their careers. The participants included (a) Robin, a female…

  2. A Perspective on Quercus Life History Characteristics and Forest Diturbance

    Treesearch

    Richard P. Guyette; Rose-Marie Muzika; John Kabrick; Michael C. Stambaugh

    2004-01-01

    Plant strategy theory suggests that life history characteristics reflect growth and reproductive adaptations to environmental disturbance. Species characteristics and abundance should correspond to predictions based on competitive ability and maximizing fitness in a given disturbance environment. A significant canonical correlation between oak growth attributes (height...

  3. On the Psychometric Study of Human Life History Strategies.

    PubMed

    Richardson, George B; Sanning, Blair K; Lai, Mark H C; Copping, Lee T; Hardesty, Patrick H; Kruger, Daniel J

    2017-01-01

    This article attends to recent discussions of validity in psychometric research on human life history strategy (LHS), provides a constructive critique of the extant literature, and describes strategies for improving construct validity. To place the psychometric study of human LHS on more solid ground, our review indicates that researchers should (a) use approaches to psychometric modeling that are consistent with their philosophies of measurement, (b) confirm the dimensionality of life history indicators, and (c) establish measurement invariance for at least a subset of indicators. Because we see confirming the dimensionality of life history indicators as the next step toward placing the psychometrics of human LHS on more solid ground, we use nationally representative data and structural equation modeling to test the structure of middle adult life history indicators. We found statistically independent mating competition and Super-K dimensions and the effects of parental harshness and childhood unpredictability on Super-K were consistent with past research. However, childhood socioeconomic status had a moderate positive effect on mating competition and no effect on Super-K, while unpredictability did not predict mating competition. We conclude that human LHS is more complex than previously suggested-there does not seem to be a single dimension of human LHS among Western adults and the effects of environmental components seem to vary between mating competition and Super-K.

  4. Life-history syndromes: integrating dispersal through space and time.

    PubMed

    Buoro, Mathieu; Carlson, Stephanie M

    2014-06-01

    Recent research has highlighted interdependencies between dispersal and other life-history traits, i.e. dispersal syndromes, thereby revealing constraints on the evolution of dispersal and opportunities for improved ability to predict dispersal by considering suites of dispersal-related traits. This review adds to the growing list of life-history traits linked to spatial dispersal by emphasising the interdependence between dispersal through space and time, i.e. life-history diversity that distributes individuals into separate reproductive events. We reviewed the literature that has simultaneously investigated spatial and temporal dispersal to examine the prediction that traits of these two dispersal strategies are negatively correlated. Our results suggest that negative covariation is widely anticipated from theory. Empirical studies often reported evidence of weak negative covariation, although more complicated patterns were also evident, including across levels of biological organisation. Existing literature has largely focused on plants with dormancy capability, one or two phases of the dispersal process (emigration and/or transfer) and a single level of biological organisation (theory: individual; empirical: species). We highlight patterns of covariation across levels of organisation and conclude with a discussion of the consequences of dispersal through space and time and future research areas that should improve our understanding of dispersal-related life-history syndromes. © 2014 John Wiley & Sons Ltd/CNRS.

  5. Life-history plasticity in female threespine stickleback

    PubMed Central

    Baker, J A; Wund, M A; Heins, D C; King, R W; Reyes, M L; Foster, S A

    2015-01-01

    The postglacial adaptive radiation of the threespine stickleback fish (Gasterosteus aculeatus) has been widely used to investigate the roles of both adaptive evolution and plasticity in behavioral and morphological divergence from the ancestral condition represented by present-day oceanic stickleback. These phenotypes tend to exhibit high levels of ecotypic differentiation. Population divergence in life history has also been well studied, but in contrast to behavior and morphology, the extent and importance of plasticity has been much less well studied. In this review, we summarize what is known about life-history plasticity in female threespine stickleback, considering four traits intimately associated with reproductive output: age/size at maturation, level of reproductive effort, egg size and clutch size. We envision life-history plasticity in an iterative, ontogenetic framework, in which females may express plasticity repeatedly across each of several time frames. We contrast the results of laboratory and field studies because, for most traits, these approaches give somewhat different answers. We provide ideas on what the cues might be for observed plasticity in each trait and, when possible, we inquire about the relative costs and benefits to expressed plasticity. We end with an example of how we think plasticity may play out in stickleback life history given what we know of plasticity in the ancestor. PMID:26286665

  6. Novelty and Innovation in the History of Life.

    PubMed

    Erwin, Douglas H

    2015-10-05

    The history of life as documented by the fossil record encompasses evolutionary diversifications at scales ranging from the Ediacaran-Cambrian explosion of animal life and the invasion of land by vascular plants, insects and vertebrates to the diversification of flowering plants over the past 100 million years and the radiation of horses. Morphological novelty and innovation has been a recurrent theme. The architects of the modern synthesis of evolutionary theory made three claims about evolutionary novelty and innovation: first, that all diversifications in the history of life represent adaptive radiations; second, that adaptive radiations are driven principally by ecological opportunity rather than by the supply of new morphological novelties, thus the primary questions about novelty and innovation focus on their ecological and evolutionary success; and third, that the rate of morphological divergence between taxa was more rapid early in the history of a clade but slowed over time as ecological opportunities declined. These claims have strongly influenced subsequent generations of evolutionary biologists, yet over the past two decades each has been challenged by data from the fossil record, by the results of comparative phylogenetic analyses and through insights from evolutionary developmental biology. Consequently a broader view of novelty and innovation is required. An outstanding issue for future work is identifying the circumstances associated with different styles of diversification and whether their frequency has changed through the history of life.

  7. America: History and Life--A Wide Ranging Database.

    ERIC Educational Resources Information Center

    Sweetland, James H.

    1983-01-01

    Description of America: History and Life (AHL)--database including references from over 2,000 periodicals in literature, philosophy, religion, art, sociology, other disciplines of historical value--highlights structure; document treatment; access points; comparison of dissertation coverage between AHL and Comprehensive Dissertation Abstracts;…

  8. Life-history evolution in ants: the case of Cardiocondyla.

    PubMed

    Heinze, Jürgen

    2017-03-15

    Ants are important components of most terrestrial habitats, and a better knowledge of the diversity of their life histories is essential to understand many aspects of ecosystem functioning. The myrmicine genus Cardiocondyla shows a wide range of colony structures, reproductive behaviours, queen and male lifespans, and habitat use. Reconstructing the evolutionary pathways of individual and social phenotypic traits suggests that the ancestral life history of Cardiocondyla was characterized by the presence of multiple, short-lived queens in small-sized colonies and a male polyphenism with winged dispersers and wingless fighters, which engage in lethal combat over female sexuals within their natal nests. Single queening, queen polyphenism, the loss of winged males and tolerance among wingless males appear to be derived traits that evolved with changes in nesting habits, colony size and the spread from tropical to seasonal environments. The aim of this review is to bring together the information on life-history evolution in Cardiocondyla and to highlight the suitability of this genus for functional genomic studies of adaptation, phenotypic plasticity, senescence, invasiveness and other key life-history traits of ants.

  9. Temperature and kairomone induced life history plasticity in coexisting Daphnia

    USGS Publications Warehouse

    Bernot, R.J.; Dodds, W.K.; Quist, M.C.; Guy, C.S.

    2006-01-01

    We investigated the life history alterations of coexisting Daphnia species responding to environmental temperature and predator cues. In a laboratory experiment, we measured Daphnia life history plasticity under different predation risk and temperature treatments that simulate changing environmental conditions. Daphnia pulicaria abundance and size at first reproduction (SFR) declined, while ephippia (resting egg) formation increased at high temperatures. Daphnia mendotae abundance and clutch size increased with predation risk at high temperatures, but produced few ephippia. Thus, each species exhibited phenotypic plasticity, but responded in sharply different ways to the same environmental cues. In Glen Elder reservoir, Kansas USA, D. pulicaria dominance shifted to D. mendotae dominance as temperature and predation risk increased from March to June in both 1999 and 2000. Field estimates of life history shifts mirrored the laboratory experiment results, suggesting that similar phenotypic responses to seasonal cues contribute to seasonal Daphnia population trends. These results illustrate species-specific differences in life history plasticity among coexisting zooplankton taxa. ?? Springer-Verlag 2006.

  10. [End-of-life decision-making process].

    PubMed

    Steinberg, Avraham

    2003-10-01

    Since time immemorial the attitude toward the dying patient has been one of the most difficult issues in medical ethics. The diversity of philosophical, religious, social and legal approaches does not enable one to reach a universal consensus to solve the many problems involved in end-of-life decisions. Within the health care system in Israel there is currently no consensual practice concerning the dying patient. Moreover, there is no published information on the actual decision-making processes within hospitals, hospices and geriatric facilities in Israel concerning the dying patient. A group of investigators in Shaare Zedek Medical Center in Jerusalem recently performed a prospective study to explore the decision-making process concerning DNR orders within this hospital. The results of this study demonstrated that the terminally-ill patients never take part in the decision-making process, they are never consulted about their wishes, and there is no effort to discover their previous wishes concerning their treatment at the terminal stages. Moreover, in many instances even the family was not consulted and did not take part in the decision-making process. In a significant minority, the final decision of a DNR order was undertaken by a single physician. This approach represents an extreme form of unethical paternalism, and it requires an urgent societal intervention to establish an ethically sound decision-making process. Recently, a national committee ("Steinberg Committee") formulated a widely agreed upon legislative proposal organizing all the fundamental and practical issues related to the dying patient. This proposal is based upon a balance between opposing values such as autonomy, life, quality-of-life, beneficence, non-maleficence and "slippery-slope" concerns. It relates to various treatment modalities, such as resuscitation, ventilation, dialysis, medication and sustenance. It establishes a clear position on euthanasia, physician-assisted suicide

  11. The Dutch model for legalizing end-of-life decisions.

    PubMed

    Kater, Loes

    2003-01-01

    The Dutch experience with euthanasia is used as a model for other countries for regulating end-of-life decisions. Several elements of the Dutch debate, for example the definition of euthanasia, are copied and imported to other debates. This paper studies the specific Dutch construction of regulating euthanasia and the concept of the requirements of prudent practice. The requirements of prudent practice embody the conditions for careful medical management in end-of-life decisions. It is argued that the requirements of prudent practice are a relatively acceptable way of regulating the Dutch practice of euthanasia as they are embedded in an elaborate network of relations, standards and values. As a consequence of this local character and the way the requirements of prudent practice relate to the Dutch practice of euthanasia it is difficult to simply transport them to other countries in order to regulate euthanasia.

  12. Decision-making heuristics and biases across the life span

    PubMed Central

    Strough, JoNell; Karns, Tara E.; Schlosnagle, Leo

    2013-01-01

    We outline a contextual and motivational model of judgment and decision-making (JDM) biases across the life span. Our model focuses on abilities and skills that correspond to deliberative, experiential, and affective decision-making processes. We review research that addresses links between JDM biases and these processes as represented by individual differences in specific abilities and skills (e.g., fluid and crystallized intelligence, executive functioning, emotion regulation, personality traits). We focus on two JDM biases—the sunk-cost fallacy (SCF) and the framing effect. We trace the developmental trajectory of each bias from preschool through middle childhood, adolescence, early adulthood, and later adulthood. We conclude that life-span developmental trajectories differ depending on the bias investigated. Existing research suggests relative stability in the framing effect across the life span and decreases in the SCF with age, including in later life. We highlight directions for future research on JDM biases across the life span, emphasizing the need for process-oriented research and research that increases our understanding of JDM biases in people’s everyday lives. PMID:22023568

  13. Brains, teeth and life histories in hominins: a review.

    PubMed

    Bermúdez de Castro, José María; Modesto-Mata, Mario; Martinón-Torres, María

    2015-07-20

    The role of the brain in the somatic development, as well as in the establishment of the different variables of the life history pattern in vertebrates has been largely debated. Moreover, during the last thirty years, dental development has been used as a good proxy to infer different aspects of the life history in hominins, primarily due to the correlation that exists between age at first molar eruption and brain size in the order Primates. We review these questions using what is known about brain growth and maturation, dental development and life history pattern, mainly in Homo sapiens and Pan troglodytes. It has been assumed that the brain represents the pace-maker of our development. However, we consider that our particular phenotype is the result of a hierarchical genetic program modulated by epigenetic and environmental factors. The particular bauplan of any kind of organisms (e.g. primates) may explain the high correlation observed between different variables of its life history pattern, brain size or dental development. However, the correlation of these variables seems to be less reliable when dealing with low-rank taxonomical categories (i.e., species). We suggest that, while there is likely some relationship between the rate of somatic development and tooth development, our brain size and maturation (and, by extension, those of other species of the genus Homo) have derived towards a particular trajectory, with a unique pattern of prenatal and postnatal time and rate of growth and, particularly, with remarkable slow brain maturation. We suggest that extremely slow brain maturation could be a very recent acquisition of the last H. sapiens populations. Furthermore, our review of the literature suggests caution in drawing conclusions about aspects of the life history of the hominins from the information we can obtain from dental development in fossil specimens.

  14. The Rate-Size Trade-Off Structures Intraspecific Variation in Daphnia ambigua Life History Parameters

    PubMed Central

    DeLong, John P.; Hanley, Torrance C.

    2013-01-01

    The identification of trade-offs is necessary for understanding the evolution and maintenance of diversity. Here we employ the supply-demand (SD) body size optimization model to predict a trade-off between asymptotic body size and growth rate. We use the SD model to quantitatively predict the slope of the relationship between asymptotic body size and growth rate under high and low food regimes and then test the predictions against observations for Daphnia ambigua. Close quantitative agreement between observed and predicted slopes at both food levels lends support to the model and confirms that a ‘rate-size’ trade-off structures life history variation in this population. In contrast to classic life history expectations, growth and reproduction were positively correlated after controlling for the rate-size trade-off. We included 12 Daphnia clones in our study, but clone identity explained only some of the variation in life history traits. We also tested the hypothesis that growth rate would be positively related to intergenic spacer length (i.e. the growth rate hypothesis) across clones, but we found that clones with intermediate intergenic spacer lengths had larger asymptotic sizes and slower growth rates. Our results strongly support a resource-based optimization of body size following the SD model. Furthermore, because some resource allocation decisions necessarily precede others, understanding interdependent life history traits may require a more nested approach. PMID:24312518

  15. Development of a diagnostic decision tree for obstructive pulmonary diseases based on real-life data.

    PubMed

    Metting, Esther I; In 't Veen, Johannes C C M; Dekhuijzen, P N Richard; van Heijst, Ellen; Kocks, Janwillem W H; Muilwijk-Kroes, Jacqueline B; Chavannes, Niels H; van der Molen, Thys

    2016-01-01

    The aim of this study was to develop and explore the diagnostic accuracy of a decision tree derived from a large real-life primary care population. Data from 9297 primary care patients (45% male, mean age 53±17 years) with suspicion of an obstructive pulmonary disease was derived from an asthma/chronic obstructive pulmonary disease (COPD) service where patients were assessed using spirometry, the Asthma Control Questionnaire, the Clinical COPD Questionnaire, history data and medication use. All patients were diagnosed through the Internet by a pulmonologist. The Chi-squared Automatic Interaction Detection method was used to build the decision tree. The tree was externally validated in another real-life primary care population (n=3215). Our tree correctly diagnosed 79% of the asthma patients, 85% of the COPD patients and 32% of the asthma-COPD overlap syndrome (ACOS) patients. External validation showed a comparable pattern (correct: asthma 78%, COPD 83%, ACOS 24%). Our decision tree is considered to be promising because it was based on real-life primary care patients with a specialist's diagnosis. In most patients the diagnosis could be correctly predicted. Predicting ACOS, however, remained a challenge. The total decision tree can be implemented in computer-assisted diagnostic systems for individual patients. A simplified version of this tree can be used in daily clinical practice as a desk tool.

  16. The life history of Pleurogenoides orientalis (Srivastava, 1934) (Trematoda: Lecithodendriidae).

    PubMed

    Madhavi, R; Dhanumkumari, C; Ratnakumari, T B

    1987-01-01

    The life history of Pleurogenoides orientalis (Srivastava 1934), a lecithodendriid trematode of frogs in India is reported and stages in the life history are described. Natural infections with cercariae, which are virgulate xiphidiocercous type, were found in the prosobranch snail Alocinma travancorica. Metacercarial cysts were found in dragon-fly naiads (Tholymis tillarga and Tramea limbata) and aquatic bugs (Laccotrephes griseus and Ranatra elongata) collected from a stream. Adults occurred in the intestine of the pong frog, Rana cyanophlyctis. Laboratory reared A. travancorica fed with eggs of P. orientalis started shedding cercariae from 30 days post feeding. Development of cercariae into infective metacercariae in dragon-fly naiads took 18 days. Mature flukes were recovered from the intestine of experimentally infected R. cyanophlyctis. The entire life cycle from egg to egg producing adult takes 2 1/2 to 3 months.

  17. Team Leadership and Cancer End-of-Life Decision Making.

    PubMed

    Waldfogel, Julie M; Battle, Dena J; Rosen, Michael; Knight, Louise; Saiki, Catherine B; Nesbit, Suzanne A; Cooper, Rhonda S; Browner, Ilene S; Hoofring, Laura H; Billing, Lynn S; Dy, Sydney M

    2016-11-01

    End-of-life decision making in cancer can be a complicated process. Patients and families encounter multiple providers throughout their cancer care. When the efforts of these providers are not well coordinated in teams, opportunities for high-quality, longitudinal goals of care discussions can be missed. This article reviews the case of a 55-year-old man with lung cancer, illustrating the barriers and missed opportunities for end-of-life decision making in his care through the lens of team leadership, a key principle in the science of teams. The challenges demonstrated in this case reflect the importance of the four functions of team leadership: information search and structuring, information use in problem solving, managing personnel resources, and managing material resources. Engaging in shared leadership of these four functions can help care providers improve their interactions with patients and families concerning end-of-life care decision making. This shared leadership can also produce a cohesive care plan that benefits from the expertise of the range of available providers while reflecting patient needs and preferences. Clinicians and researchers should consider the roles of team leadership functions and shared leadership in improving patient care when developing and studying models of cancer care delivery.

  18. Bringing history to life: simulating landmark experiments in psychology.

    PubMed

    Boynton, David M; Smith, Laurence D

    2006-05-01

    The course in history of psychology can be challenging for students, many of whom enter it with little background in history and faced with unfamiliar names and concepts. The sheer volume of material can encourage passive memorization unless efforts are made to increase student involvement. As part of a trend toward experiential history, historians of science have begun to supplement their lectures with demonstrations of classic physics experiments as a way to bring the history of science to life. Here, the authors report on computer simulations of five landmark experiments from early experimental psychology in the areas of reaction time, span of attention, and apparent motion. The simulations are designed not only to permit hands-on replication of historically important results but also to reproduce the experimental procedures closely enough that students can gain a feel for the nature of early research and the psychological processes being studied.

  19. Women's life cycle and abortion decision in unintended pregnancies.

    PubMed

    Sihvo, S; Bajos, N; Ducot, B; Kaminski, M

    2003-08-01

    To study the impact of sociodemographic, financial, and reproductive factors and of characteristics related to intimate relationships on the decisions of women in different age groups about whether or not to continue an unintended pregnancy. Cross sectional population based survey. Telephone interview survey between September 2000 and January 2001 in France. From a representative sample (n=14704) of 18 to 44 year old women, those who in the past five years had an abortion or whose last pregnancy was unintended were oversampled (sampling fraction=100%, n=1034) while the other women were randomly selected (sampling fraction =19%, n=1829). Altogether, 2863 women answered the questionnaire. All women whose last pregnancy was unintended and ended in induced abortion or birth (n=645). Factors associated with the abortion decision varied strongly according to age. Younger women's abortion decisions were mainly related to being a student and being single. Wanting to stop childbearing when the desired number of children was achieved best explained the decision to have an abortion among 25 to 34 year old women. Older women chose abortion especially when childbearing did not fit their work situation or when the relationship with the partner was unstable. A high level of education of a woman and her partner increased the likelihood of abortion, especially among young women. The impact of socioeconomic and relationship factors on the decision to have an abortion is not the same at different stages in life, and refers to the social representations and perceptions of what good conditions are for being a mother.

  20. Telling Modernization: Three Voices. Life History, Gender and the Discourse of Modernization. Roskilde University Life History Project Paper.

    ERIC Educational Resources Information Center

    Anderson, Linda

    The relationship between life history, gender, and the discourse of modernization was examined from the perspective of a researcher with extensive experience performing evaluations about modernization within human services in Denmark. Three stories about site-based management in two human service institutionsa youth center and a boarding school…

  1. [Mathematical modeling of life history evolution: a brief history and main trends].

    PubMed

    Budilova, E V; Terekhin, A T

    2010-01-01

    A brief history is recounted of the mathematical theory of life history evolution which originates from works by L. Euler, T. Malthus, A. Lotka, and R. Fisher, but has been developed in its final form in 1970s. Basic approaches to modeling life history evolutionary ecology--the explicit, optimization, and adaptive dynamics ones--are evaluated with an emphasis on their methodological advantages and shortcomings. The explicit approach deals with direct modeling of coupled changes in size of populations--which are treated as assemblages of individuals with different life history strategies--and takes into account the interactions between populations themselves and between populations and their environment. The approach is methodologically transparent, though requires a great deal of computing resources for resolving problems complex in formulation. Besides, since it deals with specific modeling situations, it is not well suited for drawing general conclusions. The optimization approach is grounded on a search for life history strategies ensuring the maximization of the given measure of evolutionary fitness--most often, lifetime reproductive success or Malthusian parameter. Owing to the possibility for applying efficient analytical or numerical methods from the mathematical theory of optimal control, it allows to reveal optimal evolutionary strategies in rather complicated situations. Still, its usage is associated with significant methodological obstacles originated from the necessity of optimization criterion substantiation. The adaptive dynamics approach addresses to methods of the qualitative theory of differential equations while investigating evolutionary changes in phenotypic traits and life history strategies in particular. Within its framework, interactions between the main population (resident) and an alien population (invader), which is very small in size, are modeled. This approach allows to explore subtle aspects of evolutionary dynamics and to formulate

  2. Life science teachers' decision making on sex education

    NASA Astrophysics Data System (ADS)

    Gill, Puneet Singh

    The desires of young people and especially young bodies are constructed at the intersections of policies that set the parameters of sex education policies, the embodied experiences of students in classrooms, and the way bodies are discussed in the complex language of science. Moreover, more research points to the lack of scientifically and medically accurate information about sex education. Through this research, I hope to extend the discussion about sex education to life science classrooms, where youth can discuss how sex occurs according to scientific concepts and processes. However, science classrooms are caught in a double bind: They maintain positivist methods of teaching science while paying little attention to the nature of science or the nature and function of science that offer explanations of scientific phenomena. In this study, I describe how science teachers made decisions about what to include or not include about sexuality in a life science classroom and the discursive frameworks that shaped these decisions. I also analyzed the ways that these relationships functioned to produce certain truths, or discourses. The current trends in research concerning SSI are pointing to understanding how controversial issues are framed according to personal philosophies, identities, and teaching approaches. If we can understand science teachers' inner aspects as they relate to sexuality education, we can also understand the deep-seeded motivations behind how these specific issues are being taught. In science classrooms where a discussion of the body is part of the curriculum, specific discourses of the body and sex/sexuality are excluded. In this study, I describe how science teachers made decisions about what to include or not include about sexuality in a life science classroom and the discursive practices that shaped these decisions.

  3. Complainant Sexual History Evidence: Its Impact on Mock Jurors' Decisions

    ERIC Educational Resources Information Center

    Schuller, Regina A.; Hastings, Patricia A.

    2002-01-01

    The current study examined the impact of complainant sexual history evidence on mock jurors' judgements in a sexual assault trial. One hundred and sixty-nine undergraduates listened to an audiotape of a sexual assault trial in which the sexual history between the complainant and defendant was systematically varied to include either sexual…

  4. Complainant Sexual History Evidence: Its Impact on Mock Jurors' Decisions

    ERIC Educational Resources Information Center

    Schuller, Regina A.; Hastings, Patricia A.

    2002-01-01

    The current study examined the impact of complainant sexual history evidence on mock jurors' judgements in a sexual assault trial. One hundred and sixty-nine undergraduates listened to an audiotape of a sexual assault trial in which the sexual history between the complainant and defendant was systematically varied to include either sexual…

  5. Life histories predict vulnerability to overexploitation in parrotfishes

    NASA Astrophysics Data System (ADS)

    Taylor, Brett M.; Houk, Peter; Russ, Garry R.; Choat, J. Howard

    2014-12-01

    A scarcity of life-history data currently exists for many exploited coral reef fishes, hindering our ability to interpret fishery dynamics and develop sound conservation policies. In particular, parrotfishes (Family Labridae) represent a ubiquitous and ecologically important group that is increasingly prevalent in commercial and artisanal fisheries worldwide. We used both fishery-dependent and fishery-independent data to examine the effect of life histories on vulnerability to overexploitation in parrotfishes. Vulnerability for each species was derived from independent measures associated with both temporal (20-year catch records) and spatial datasets. Most life-history traits examined were significant predictors of vulnerability across species, but their relative utility differed considerably. Length-based traits (e.g., lengths at maturity and sex change, maximum length) were generally superior to age-based traits (e.g., life span), but one age-based trait, age at female maturation, was the best predictor. The results suggest that easily derived metrics such as maximum length can be effective measures of sensitivity to exploitation when applied to phylogenetically related multispecies assemblages, but more holistic and comprehensive age-based demographic data should be sought, especially in data-deficient and heavily impacted regions. Given the increasing prevalence of parrotfishes in the global coral reef harvest, species-specific responses demonstrate the capacity for heavy fishing pressure to alter parrotfish assemblages considerably.

  6. Phenotypic plasticity in adult life-history strategies compensates for a poor start in life in Trinidadian guppies (Poecilia reticulata).

    PubMed

    Auer, Sonya K

    2010-12-01

    Low food availability during early growth and development can have long-term negative consequences for reproductive success. Phenotypic plasticity in adult life-history decisions may help to mitigate these potential costs, yet adult life-history responses to juvenile food conditions remain largely unexplored. I used a food-manipulation experiment with female Trinidadian guppies (Poecilia reticulata) to examine age-related changes in adult life-history responses to early food conditions, whether these responses varied across different adult food conditions, and how these responses affected overall reproductive success. Guppy females reared on low food as juveniles matured at a later age, at a smaller size, and with less energy reserves than females reared on high food as juveniles. In response to this setback, they changed their investment in growth, reproduction, and fat storage throughout the adult stage such that they were able to catch up in body size, increase their reproductive output, and restore their energy reserves to levels comparable to those of females reared on high food as juveniles. The net effect was that adult female guppies did not merely mitigate but surprisingly were able to fully compensate for the potential long-term negative effects of poor juvenile food conditions on reproductive success.

  7. Early life environment and natural history of inflammatory bowel diseases.

    PubMed

    Guo, Abra Y; Stevens, Betsy W; Wilson, Robin G; Russell, Caitlin N; Cohen, Melissa A; Sturgeon, Holly C; Thornton, Anna; Giallourakis, Cosmas; Khalili, Hamed; Nguyen, Deanna D; Sauk, Jenny; Yajnik, Vijay; Xavier, Ramnik J; Ananthakrishnan, Ashwin N

    2014-12-16

    Early life exposures may modify risk of inflammatory bowel diseases (IBD; Crohn's disease (CD), ulcerative colitis (UC)). However, the relationship between early life exposures and natural history of IBD has not been previously examined. This single center study included patients with CD or UC recruited in a prospective IBD registry. Enrolled patients completed a detailed environmental questionnaire that assessed various early life environmental exposures. Our primary outcome was requirement for disease-related surgery in CD and UC. Logistic regression models defined independent effect of early life exposures, adjusting for potential confounders. Our study included 333 CD and 270 UC patients. Just over half were female with a median age at diagnosis of 25 years. One-third of the cohort had history of bowel surgery (31%) and nearly half had used at least one biologic agent (47%). Among those with CD, being breastfed was associated with reduced risk of CD-related surgery (34% vs. 55%), while childhood cigarette smoke exposure was associated with increased risk. On multivariate analysis, history of being breastfed (odds ratio (OR) 0.21, 95% confidence interval [CI] 0.09-0.46) and cigarette smoke exposure as a child (OR 2.17, 95% CI 1.10-4.29) remained independently associated with surgery. None of the early life variables influenced disease phenotype or outcome in UC. A history of being breastfed was associated with a decreased risk while childhood cigarette smoke exposure was associated with an increased risk of surgery in patients with CD. Further investigation to examine biological mechanisms is warranted.

  8. Unravelling the life history of Amazonian fishes through otolith microchemistry

    PubMed Central

    Hermann, Theodore W.; Stewart, Donald J.; Limburg, Karin E.; Castello, Leandro

    2016-01-01

    Amazonian fishes employ diverse migratory strategies, but the details of these behaviours remain poorly studied despite numerous environmental threats and heavy commercial exploitation of many species. Otolith microchemistry offers a practical, cost-effective means of studying fish life history in such a system. This study employed a multi-method, multi-elemental approach to elucidate the migrations of five Amazonian fishes: two ‘sedentary’ species (Arapaima sp. and Plagioscion squamosissimus), one ‘floodplain migrant’ (Prochilodus nigricans) and two long-distance migratory catfishes (Brachyplatystoma rousseauxii and B. filamentosum). The Sr : Ca and Zn : Ca patterns in Arapaima were consistent with its previously observed sedentary life history, whereas Sr : Ca and Mn : Ca indicated that Plagioscion may migrate among multiple, chemically distinct environments during different life-history stages. Mn : Ca was found to be potentially useful as a marker for identifying Prochilodus's transition from its nursery habitats into black water. Sr : Ca and Ba : Ca suggested that B. rousseauxii resided in the Amazon estuary for the first 1.5–2 years of life, shown by the simultaneous increase/decrease of otolith Sr : Ca/Ba : Ca, respectively. Our results further suggested that B. filamentosum did not enter the estuary during its life history. These results introduce what should be a productive line of research desperately needed to better understand the migrations of these unique and imperilled fishes. PMID:27429777

  9. Labelling of end-of-life decisions by physicians.

    PubMed

    Deyaert, Jef; Chambaere, Kenneth; Cohen, Joachim; Roelands, Marc; Deliens, Luc

    2014-07-01

    Potentially life-shortening medical end-of-life practices (end-of-life decisions (ELDs)) remain subject to conceptual vagueness. This study evaluates how physicians label these practices by examining which of their own practices (described according to the precise act, the intention, the presence of an explicit patient request and the self-estimated degree of life shortening)they label as euthanasia or sedation. We conducted a large stratified random sample of death certificates from 2007 (N=6927).The physicians named on the death certificate were approached by means of a postal questionnaire asking about ELDs made in each case and asked to choose the most appropriate label to describe the ELD. Response rate was 58.4%. In the vast majority of practices labelled as euthanasia, the self-reported actions of the physicians corresponded with the definition in the Belgian euthanasia legislation; practices labelled as palliative or terminal sedation lack clear correspondence with definitions of sedation as presented in existing guidelines. In these cases, an explicit life-shortening intention by means of drug administration was present in 21.6%, life shortening was estimated at more than 24 h in 51% and an explicit patient request was absentin 79.7%. Our results suggest that, unlike euthanasia,the concept of palliative or terminal sedation covers abroad range of practices in the minds of physicians. This ambiguity can be a barrier to appropriate sedation practice and indicates a need for better knowledge of the practice of palliative sedation by physicians.

  10. Decision Models for Determining the Optimal Life Test Sampling Plans

    NASA Astrophysics Data System (ADS)

    Nechval, Nicholas A.; Nechval, Konstantin N.; Purgailis, Maris; Berzins, Gundars; Strelchonok, Vladimir F.

    2010-11-01

    Life test sampling plan is a technique, which consists of sampling, inspection, and decision making in determining the acceptance or rejection of a batch of products by experiments for examining the continuous usage time of the products. In life testing studies, the lifetime is usually assumed to be distributed as either a one-parameter exponential distribution, or a two-parameter Weibull distribution with the assumption that the shape parameter is known. Such oversimplified assumptions can facilitate the follow-up analyses, but may overlook the fact that the lifetime distribution can significantly affect the estimation of the failure rate of a product. Moreover, sampling costs, inspection costs, warranty costs, and rejection costs are all essential, and ought to be considered in choosing an appropriate sampling plan. The choice of an appropriate life test sampling plan is a crucial decision problem because a good plan not only can help producers save testing time, and reduce testing cost; but it also can positively affect the image of the product, and thus attract more consumers to buy it. This paper develops the frequentist (non-Bayesian) decision models for determining the optimal life test sampling plans with an aim of cost minimization by identifying the appropriate number of product failures in a sample that should be used as a threshold in judging the rejection of a batch. The two-parameter exponential and Weibull distributions with two unknown parameters are assumed to be appropriate for modelling the lifetime of a product. A practical numerical application is employed to demonstrate the proposed approach.

  11. Caring Decisions: The Development of a Written Resource for Parents Facing End-of-Life Decisions

    PubMed Central

    Gillam, Lynn; Hynson, Jenny; Sullivan, Jane; Cossich, Mary; Wilkinson, Dominic

    2015-01-01

    Abstract Background: Written resources in adult intensive care have been shown to benefit families facing end of life (EoL) decisions. There are few resources for parents making EoL decisions for their child and no existing resources addressing ethical issues. The Caring Decisions handbook and website were developed to fill these gaps. Aim: We discuss the development of the resources, modification after reviewer feedback and findings from initial pilot implementation. Design: A targeted literature review-to identify resources and factors that impact on parental EoL decision-making; development phase-guided by the literature and the researchers' expertise; consultation process-comprised a multi-disciplinary panel of experts and parents; pilot evaluation study-hard-copy handbook was distributed as part of routine care at an Australian Children's Hospital. Setting/Participants: Twelve experts and parents formed the consultation panel. Eight parents of children with life-limiting conditions and clinicians were interviewed in the pilot study. Results: Numerous factors supporting/impeding EoL decisions were identified. Caring Decisions addressed issues identified in the literature and by the multidisciplinary research team. The consultation panel provided overwhelmingly positive feedback. Pilot study parents found the resources helpful and comforting. Most clinicians viewed the resources as very beneficial to parents and identified them as ideal for training purposes. Conclusions: The development of the resources addressed many of the gaps in existing resources. The consultation process and the pilot study suggest these resources could be of significant benefit to parents and clinicians. PMID:26418215

  12. Parental History of Disruptive Life Events and Household Food Insecurity.

    PubMed

    Jackson, Dylan B; Vaughn, Michael G

    To investigate whether a history of disruptive life events (ie, school suspension or expulsion, job termination, hospitalization for mental health, and/or criminal justice involvement) among parents is positively associated with household food insecurity. Structured interviews and self-report surveys. Households across all 50 states in the US. Subsample of 6,270 households that participated in the Early Childhood Longitudinal Study-Birth Cohort with valid maternal and paternal data. Food insecurity was measured when children were aged 9 months (wave 1), 2 years (wave 2), and 4 years (wave 3). Parental history of disruptive life events was measured at wave 1. Logistic regression was used to carry out the analyses. Each examined disruptive life event was associated with a significant increase in the odds of persistent household food insecurity (P < .05). The probability of persistent household food insecurity was >6 times as large in households with 1 or both parents reporting the occurrence of each of the disruptive life events, relative to households with none of these parental risk factors. Practitioners may want to consider parental history of various disruptive life events in their assessment of familial risk of household food insecurity. Future policy efforts might include a cost-benefit estimate analysis of intervening earlier in the food insecurity-disruptive life events nexus to advocate for savings to the taxpayer for prevention services. Moreover, future research could evaluate these practice and policy-driven efforts using quasi-experimental designs. Copyright © 2017 Society for Nutrition Education and Behavior. Published by Elsevier Inc. All rights reserved.

  13. Life-history strategy, food choice, and caloric consumption.

    PubMed

    Laran, Juliano; Salerno, Anthony

    2013-02-01

    Do people's perceptions that they live in a harsh environment influence their food choices? Drawing on life-history theory, we propose that cues indicating that the current environment is harsh (e.g., news about an economic crisis, the sight of people facing adversity in life) lead people to perceive that resources in the world are scarce. As a consequence, people seek and consume more filling and high-calorie foods, which they believe will sustain them for longer periods of time. Although perceptions of harshness can promote unhealthy eating, we show how this effect can be attenuated and redirected to promote healthier food choices.

  14. Life histories and the evolution of cooperative breeding in mammals

    PubMed Central

    Lukas, Dieter; Clutton-Brock, Tim

    2012-01-01

    While the evolution of cooperative breeding systems (where non-breeding helpers participate in rearing young produced by dominant females) has been restricted to lineages with socially monogamous mating systems where coefficients of relatedness between group members are usually high, not all monogamous lineages have produced species with cooperative breeding systems, suggesting that other factors constrain the evolution of cooperative breeding. Previous studies have suggested that life-history parameters, including longevity, may constrain the evolution of cooperative breeding. Here, we show that transitions to cooperative breeding across the mammalian phylogeny have been restricted to lineages where females produce multiple offspring per birth. We find no support for effects of longevity or of other life-history parameters. We suggest that the evolution of cooperative breeding has been restricted to monogamous lineages where helpers have the potential to increase the reproductive output of breeders. PMID:22874752

  15. Life histories and the evolution of cooperative breeding in mammals.

    PubMed

    Lukas, Dieter; Clutton-Brock, Tim

    2012-10-07

    While the evolution of cooperative breeding systems (where non-breeding helpers participate in rearing young produced by dominant females) has been restricted to lineages with socially monogamous mating systems where coefficients of relatedness between group members are usually high, not all monogamous lineages have produced species with cooperative breeding systems, suggesting that other factors constrain the evolution of cooperative breeding. Previous studies have suggested that life-history parameters, including longevity, may constrain the evolution of cooperative breeding. Here, we show that transitions to cooperative breeding across the mammalian phylogeny have been restricted to lineages where females produce multiple offspring per birth. We find no support for effects of longevity or of other life-history parameters. We suggest that the evolution of cooperative breeding has been restricted to monogamous lineages where helpers have the potential to increase the reproductive output of breeders.

  16. [End of life decisions, the Dutch form through Spanish eyes].

    PubMed

    Belloc Rocasalbas, M; Girbes, A R J

    2011-03-01

    Abroad, but also in The Netherlands, there are many misunderstandings concerning end of life decisions and euthanasia. In general, euthanasia does not play any role in the intensive care units, simply because it does not fulfill the conditions to carry it out. However, there is still confusion, merely due to the assumption that the Dutch situation is different because of their legislation on euthanasia. The use of the unclear terminology such as "passive euthanasia", "voluntary euthanasia" or "involuntary euthanasia" contributes to the confusion of lay people and physicians, and should therefore be avoided. End of life decisions in intensive care patients are in fact a structural part of work of intensivists. Collecting all necessary information including the wishes and will of the patient, medical expertise and acknowledging limitations of medical treatment will help to determine futility of treatment goals. Once it is determined that surviving the intensive care unit with a quality of life acceptable for the patient is beyond reach, the goal of treatment should be improved and the dying process optimized. Stopping a treatment modality at the request of a will-competent patient or because of futility is not euthanasia. Copyright © 2010 Elsevier España, S.L. y SEMICYUC. All rights reserved.

  17. Optimal life-history strategy differs between philopatric and dispersing individuals in a metapopulation.

    PubMed

    Cotto, Olivier; Kubisch, Alexander; Ronce, Ophélie

    2014-03-01

    Abundant empirical evidence for dispersal syndromes contrasts with the rarity of theoretical predictions about the evolution of life-history divergence between dispersing and philopatric individuals. We use an evolutionary model to predict optimal differences in age-specific reproductive effort between dispersing and philopatric individuals inhabiting the same metapopulation. In our model, only young individuals disperse, and their lifelong reproductive decisions are potentially affected by this initial event. Juvenile survival declines as density of adults and other juveniles increases. We assume a trade-off between reproduction and survival, so that different patterns of age-specific reproductive effort lead to different patterns of aging. We find that young immigrant mothers should allocate more resources to reproduction than young philopatric mothers, but these life-history differences vanish as immigrant and philopatric individuals get older. However, whether the higher early reproductive effort of immigrants results in higher fecundity depends on the postimmigration cost on fecundity. Dispersing individuals have consequently a shorter life span. Ultimately, these life-history differences are due to the fact that young dispersing individuals most often live in recently founded populations, where competition is relaxed and juvenile survival higher, favoring larger investment in offspring production at the expense of survival.

  18. Extinction-effective population index: incorporating life-history variations in population viability analysis.

    PubMed

    Fujiwara, Masami

    2007-09-01

    Viability status of populations is a commonly used measure for decision-making in the management of populations. One of the challenges faced by managers is the need to consistently allocate management effort among populations. This allocation should in part be based on comparison of extinction risks among populations. Unfortunately, common criteria that use minimum viable population size or count-based population viability analysis (PVA) often do not provide results that are comparable among populations, primarily because they lack consistency in determining population size measures and threshold levels of population size (e.g., minimum viable population size and quasi-extinction threshold). Here I introduce a new index called the "extinction-effective population index," which accounts for differential effects of demographic stochasticity among organisms with different life-history strategies and among individuals in different life stages. This index is expected to become a new way of determining minimum viable population size criteria and also complement the count-based PVA. The index accounts for the difference in life-history strategies of organisms, which are modeled using matrix population models. The extinction-effective population index, sensitivity, and elasticity are demonstrated in three species of Pacific salmonids. The interpretation of the index is also provided by comparing them with existing demographic indices. Finally, a measure of life-history-specific effect of demographic stochasticity is derived.

  19. [Medical end-of-life decisions and assisted suicide].

    PubMed

    Bosshard, Georg

    2008-07-01

    Medical end-of-life decisions that potentially shorten life (Sterbehilfe) are normally divided into four categories: Passive Sterbehilfe refers to withholding or withdrawing life-prolonging measures, indirect Sterbehilfe refers to the use of agents such as opioids or sedatives to alleviate symptoms of a terminally ill patient, assisted suicide (Suizidbeihilfe or Beihilfe zum Suizid) refers to prescribing and/or supplying a lethal drug in order to help someone to end his own life, and active euthanasia - which is illegal in any circumstances - means a doctor actively ending a patients life. In passive and indirect euthanasia, the will of a competent patient, or the presumed will of an incompetent patient respectively, is crucial. Assisted suicide is not illegal according to the Swiss Penal Code as long as there are no motives of self-interest of the individual assisting, and the individual assisted has decisional capacity. However, for doctors participating in assisted suicide, specific requirements of medical due care have to be met. What this means in the context of assisted suicide has recently been elaborated by the Swiss Federal Court of Justice.

  20. Brain ontogeny and life history in Pleistocene hominins

    PubMed Central

    Hublin, Jean-Jacques; Neubauer, Simon; Gunz, Philipp

    2015-01-01

    A high level of encephalization is critical to the human adaptive niche and emerged among hominins over the course of the past 2 Myr. Evolving larger brains required important adaptive adjustments, in particular regarding energy allocation and life history. These adaptations included a relatively small brain at birth and a protracted growth of highly dependent offspring within a complex social environment. In turn, the extended period of growth and delayed maturation of the brain structures of humans contribute to their cognitive complexity. The current palaeoanthropological evidence shows that, regarding life history and brain ontogeny, the Pleistocene hominin taxa display different patterns and that one cannot simply contrast an ‘ape-model’ to a ‘human-model’. Large-brained hominins such as Upper Pleistocene Neandertals have evolved along their own evolutionary pathway and can be distinguished from modern humans in terms of growth pattern and brain development. The life-history pattern and brain ontogeny of extant humans emerged only recently in the course of human evolution. PMID:25602066

  1. The life-history basis of behavioural innovations

    PubMed Central

    Sol, Daniel; Sayol, Ferran; Ducatez, Simon; Lefebvre, Louis

    2016-01-01

    The evolutionary origin of innovativeness remains puzzling because innovating means responding to novel or unusual problems and hence is unlikely to be selected by itself. A plausible alternative is considering innovativeness as a co-opted product of traits that have evolved for other functions yet together predispose individuals to solve problems by adopting novel behaviours. However, this raises the question of why these adaptations should evolve together in an animal. Here, we develop the argument that the adaptations enabling animals to innovate evolve together because they are jointly part of a life-history strategy for coping with environmental changes. In support of this claim, we present comparative evidence showing that in birds, (i) innovative propensity is linked to life histories that prioritize future over current reproduction, (ii) the link is in part explained by differences in brain size, and (iii) innovative propensity and life-history traits may evolve together in generalist species that frequently expose themselves to novel or unusual conditions. Combined with previous evidence, these findings suggest that innovativeness is not a specialized adaptation but more likely part of a broader general adaptive system to cope with changes in the environment. PMID:26926277

  2. The life-history basis of behavioural innovations.

    PubMed

    Sol, Daniel; Sayol, Ferran; Ducatez, Simon; Lefebvre, Louis

    2016-03-19

    The evolutionary origin of innovativeness remains puzzling because innovating means responding to novel or unusual problems and hence is unlikely to be selected by itself. A plausible alternative is considering innovativeness as a co-opted product of traits that have evolved for other functions yet together predispose individuals to solve problems by adopting novel behaviours. However, this raises the question of why these adaptations should evolve together in an animal. Here, we develop the argument that the adaptations enabling animals to innovate evolve together because they are jointly part of a life-history strategy for coping with environmental changes. In support of this claim, we present comparative evidence showing that in birds, (i) innovative propensity is linked to life histories that prioritize future over current reproduction, (ii) the link is in part explained by differences in brain size, and (iii) innovative propensity and life-history traits may evolve together in generalist species that frequently expose themselves to novel or unusual conditions. Combined with previous evidence, these findings suggest that innovativeness is not a specialized adaptation but more likely part of a broader general adaptive system to cope with changes in the environment. © 2016 The Author(s).

  3. Individual heterogeneity in life histories and eco-evolutionary dynamics

    PubMed Central

    Vindenes, Yngvild; Langangen, Øystein

    2015-01-01

    Individual heterogeneity in life history shapes eco-evolutionary processes, and unobserved heterogeneity can affect demographic outputs characterising life history and population dynamical properties. Demographic frameworks like matrix models or integral projection models represent powerful approaches to disentangle mechanisms linking individual life histories and population-level processes. Recent developments have provided important steps towards their application to study eco-evolutionary dynamics, but so far individual heterogeneity has largely been ignored. Here, we present a general demographic framework that incorporates individual heterogeneity in a flexible way, by separating static and dynamic traits (discrete or continuous). First, we apply the framework to derive the consequences of ignoring heterogeneity for a range of widely used demographic outputs. A general conclusion is that besides the long-term growth rate lambda, all parameters can be affected. Second, we discuss how the framework can help advance current demographic models of eco-evolutionary dynamics, by incorporating individual heterogeneity. For both applications numerical examples are provided, including an empirical example for pike. For instance, we demonstrate that predicted demographic responses to climate warming can be reversed by increased heritability. We discuss how applications of this demographic framework incorporating individual heterogeneity can help answer key biological questions that require a detailed understanding of eco-evolutionary dynamics. PMID:25807980

  4. Individual heterogeneity in life histories and eco-evolutionary dynamics.

    PubMed

    Vindenes, Yngvild; Langangen, Øystein

    2015-05-01

    Individual heterogeneity in life history shapes eco-evolutionary processes, and unobserved heterogeneity can affect demographic outputs characterising life history and population dynamical properties. Demographic frameworks like matrix models or integral projection models represent powerful approaches to disentangle mechanisms linking individual life histories and population-level processes. Recent developments have provided important steps towards their application to study eco-evolutionary dynamics, but so far individual heterogeneity has largely been ignored. Here, we present a general demographic framework that incorporates individual heterogeneity in a flexible way, by separating static and dynamic traits (discrete or continuous). First, we apply the framework to derive the consequences of ignoring heterogeneity for a range of widely used demographic outputs. A general conclusion is that besides the long-term growth rate lambda, all parameters can be affected. Second, we discuss how the framework can help advance current demographic models of eco-evolutionary dynamics, by incorporating individual heterogeneity. For both applications numerical examples are provided, including an empirical example for pike. For instance, we demonstrate that predicted demographic responses to climate warming can be reversed by increased heritability. We discuss how applications of this demographic framework incorporating individual heterogeneity can help answer key biological questions that require a detailed understanding of eco-evolutionary dynamics. © 2015 John Wiley & Sons Ltd/CNRS.

  5. Functional genomics of life history variation in a butterfly metapopulation.

    PubMed

    Wheat, Christopher W; Fescemyer, Howard W; Kvist, J; Tas, Eva; Vera, J Cristobal; Frilander, Mikko J; Hanski, Ilkka; Marden, James H

    2011-05-01

    In fragmented landscapes, small populations frequently go extinct and new ones are established with poorly understood consequences for genetic diversity and evolution of life history traits. Here, we apply functional genomic tools to an ecological model system, the well-studied metapopulation of the Glanville fritillary butterfly. We investigate how dispersal and colonization select upon existing genetic variation affecting life history traits by comparing common-garden reared 2-day adult females from new populations with those from established older populations. New-population females had higher expression of abdomen genes involved in egg provisioning and thorax genes involved in the maintenance of flight muscle proteins. Physiological studies confirmed that new-population butterflies have accelerated egg maturation, apparently regulated by higher juvenile hormone titer and angiotensin converting enzyme mRNA, as well as enhanced flight metabolism. Gene expression varied between allelic forms of two metabolic genes (Pgi and Sdhd), which themselves were associated with differences in flight metabolic rate, population age and population growth rate. These results identify likely molecular mechanisms underpinning life history variation that is maintained by extinction-colonization dynamics in metapopulations. © 2011 Blackwell Publishing Ltd.

  6. Brain ontogeny and life history in Pleistocene hominins.

    PubMed

    Hublin, Jean-Jacques; Neubauer, Simon; Gunz, Philipp

    2015-03-05

    A high level of encephalization is critical to the human adaptive niche and emerged among hominins over the course of the past 2 Myr. Evolving larger brains required important adaptive adjustments, in particular regarding energy allocation and life history. These adaptations included a relatively small brain at birth and a protracted growth of highly dependent offspring within a complex social environment. In turn, the extended period of growth and delayed maturation of the brain structures of humans contribute to their cognitive complexity. The current palaeoanthropological evidence shows that, regarding life history and brain ontogeny, the Pleistocene hominin taxa display different patterns and that one cannot simply contrast an 'ape-model' to a 'human-model'. Large-brained hominins such as Upper Pleistocene Neandertals have evolved along their own evolutionary pathway and can be distinguished from modern humans in terms of growth pattern and brain development. The life-history pattern and brain ontogeny of extant humans emerged only recently in the course of human evolution. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  7. Interrelationships among life-history traits in three California oaks.

    PubMed

    Barringer, Brian C; Koenig, Walter D; Knops, Johannes M H

    2013-01-01

    Life-history traits interact in important ways. Relatively few studies, however, have explored the relationships between life-history traits in long-lived taxa such as trees. We examined patterns of energy allocation to components of reproduction and growth in three species of California oaks (Quercus spp.) using a combination of annual acorn censuses, dendrometer bands to measure radial increment, and litterfall traps. Our results are generally consistent with the hypothesis that energy invested in reproduction detracts from the amount of energy available for growth in these long-lived taxa; i.e., there are trade-offs between these traits. The relationships between reproduction and growth varied substantially among specific trait combinations and tree species, however, and in some cases were in the direction opposite that expected based on the assumption of trade-offs between them. This latter finding appears to be a consequence of the pattern of resource use across years in these long-lived trees contrasting with the expected partitioning of resource use within years in short-lived taxa. Thus, the existence and magnitude of putative trade-offs varied depending on whether the time scale considered was within or across years. Collectively, our results indicate that negative relationships between fundamental life-history traits can be important at multiple levels of modular organization and that energy invested in reproduction can have measurable consequences in terms of the amount of energy available for future reproduction and both current and future growth.

  8. Buddhist ethics and end-of-life care decisions.

    PubMed

    McCormick, Andrew J

    2013-01-01

    Buddhism has grown in the United States in the past 50 years. Immigrants come following long traditions. American converts are more eclectic. The first Buddhist precept prohibiting harm to living things, the virtue of compassion, and the goal of a peaceful death provide guidance for ethical decision making regarding organ donation, withholding and withdrawing life-sustaining treatment, voluntary cessation of eating, physician aid in dying, and euthanasia. Concepts and views from three Buddhist traditions and views of master practitioners are presented. Case examples illustrate some of the differences within Buddhism. Suggestions for social workers are provided.

  9. Women's life cycle and abortion decision in unintended pregnancies

    PubMed Central

    Sihvo, S; Bajos, N; Ducot, B; Kaminski, M

    2003-01-01

    Objective: To study the impact of sociodemographic, financial, and reproductive factors and of characteristics related to intimate relationships on the decisions of women in different age groups about whether or not to continue an unintended pregnancy. Design: Cross sectional population based survey. Setting: Telephone interview survey between September 2000 and January 2001 in France. From a representative sample (n=14 704) of 18 to 44 year old women, those who in the past five years had an abortion or whose last pregnancy was unintended were oversampled (sampling fraction=100%, n=1034) while the other women were randomly selected (sampling fraction =19%, n=1829). Altogether, 2863 women answered the questionnaire. Participants: All women whose last pregnancy was unintended and ended in induced abortion or birth (n=645). Main results: Factors associated with the abortion decision varied strongly according to age. Younger women's abortion decisions were mainly related to being a student and being single. Wanting to stop childbearing when the desired number of children was achieved best explained the decision to have an abortion among 25 to 34 year old women. Older women chose abortion especially when childbearing did not fit their work situation or when the relationship with the partner was unstable. A high level of education of a woman and her partner increased the likelihood of abortion, especially among young women. Conclusions: The impact of socioeconomic and relationship factors on the decision to have an abortion is not the same at different stages in life, and refers to the social representations and perceptions of what good conditions are for being a mother. PMID:12883066

  10. A review of Ruffe (Gymnocephalus cernuus) life history in its ...

    EPA Pesticide Factsheets

    Ruffe (Gymnocephalus cernuus) have caused and have the potential to cause great ecological damage as invasive species in North America, parts of the European Union, Scandinavian countries, and the United Kingdom. The objectives of this review are to define the Ruffe's native and non-native range, examine the life history requirements of Ruffe, explore the Ruffe life cycle, and differentiate between the life stages. We compare Ruffe in their native range to Ruffe in their non-native range to determine if there are any differences in habitat, size, age, genotype, or migratory patterns in the winter. Literature from both the native and non-native ranges of Ruffe, with a particular emphasis on rare translated literature, is used. Ruffe have variability and plasticity in their chemical, physical, biological, and habitat requirements in their native and non-native ranges. Adult Ruffe have a suite of characteristics that make them adaptable to novel environments, including age and size at maturity, maximum age and length (and/ or weight), reproduction type, genotype, feeding habits, seasonal movements, and spawning movements. There is variability among these characteristics seen between the Ruffe's native, non-native North American, and European non-native populations. Based on the Ruffe's variable life history strategies and their recent range expansion, all of the Great Lakes and many other regions in the U.K., Europe, and Scandinavian countries could be vulnerable t

  11. A review of Ruffe (Gymnocephalus cernuus) life history in its ...

    EPA Pesticide Factsheets

    Ruffe (Gymnocephalus cernuus) have caused and have the potential to cause great ecological damage as invasive species in North America, parts of the European Union, Scandinavian countries, and the United Kingdom. The objectives of this review are to define the Ruffe's native and non-native range, examine the life history requirements of Ruffe, explore the Ruffe life cycle, and differentiate between the life stages. We compare Ruffe in their native range to Ruffe in their non-native range to determine if there are any differences in habitat, size, age, genotype, or migratory patterns in the winter. Literature from both the native and non-native ranges of Ruffe, with a particular emphasis on rare translated literature, is used. Ruffe have variability and plasticity in their chemical, physical, biological, and habitat requirements in their native and non-native ranges. Adult Ruffe have a suite of characteristics that make them adaptable to novel environments, including age and size at maturity, maximum age and length (and/ or weight), reproduction type, genotype, feeding habits, seasonal movements, and spawning movements. There is variability among these characteristics seen between the Ruffe's native, non-native North American, and European non-native populations. Based on the Ruffe's variable life history strategies and their recent range expansion, all of the Great Lakes and many other regions in the U.K., Europe, and Scandinavian countries could be vulnerable t

  12. The Surprising History of Claims for Life on the Sun

    NASA Astrophysics Data System (ADS)

    Crowe, Michael J.

    2011-11-01

    Because astronomers are now convinced that it is impossible for life, especially intelligent life, to exist on the Sun and stars, it might be assumed that astronomers have always held this view. This paper shows that throughout most of the history of astronomy, some intellectuals, including a number of well-known astronomers, have advocated the existence of intelligent life on our Sun and thereby on stars. Among the more prominent figures discussed are Nicolas of Cusa, Giordano Bruno, William Whiston, Johann Bode, Roger Boscovich, William Herschel, Auguste Comte, Carl Gauss, Thomas Dick, John Herschel, and François Arago. One point in preparing this paper is to show differences between the astronomy of the past and that of the present.

  13. Understanding life together: A brief history of collaboration in biology

    PubMed Central

    Vermeulen, Niki; Parker, John N.; Penders, Bart

    2013-01-01

    The history of science shows a shift from single-investigator ‘little science’ to increasingly large, expensive, multinational, interdisciplinary and interdependent ‘big science’. In physics and allied fields this shift has been well documented, but the rise of collaboration in the life sciences and its effect on scientific work and knowledge has received little attention. Research in biology exhibits different historical trajectories and organisation of collaboration in field and laboratory – differences still visible in contemporary collaborations such as the Census of Marine Life and the Human Genome Project. We employ these case studies as strategic exemplars, supplemented with existing research on collaboration in biology, to expose the different motives, organisational forms and social dynamics underpinning contemporary large-scale collaborations in biology and their relations to historical patterns of collaboration in the life sciences. We find the interaction between research subject, research approach as well as research organisation influencing collaboration patterns and the work of scientists. PMID:23578694

  14. Concept of major life-changing decisions in life course research.

    PubMed

    Bhatti, Zaheer U; Salek, Sam; Finlay, Andrew Y

    2013-01-01

    Chronic diseases can severely impair patients' quality of life but little information is available about the long-term impact of chronic diseases. The chronic nature of disease may decrease patients' psychosocial well-being, may change their attitude towards life goals and influence major life-changing decisions (MLCDs). Understanding of the impact on MLCDs is largely missing from health outcomes research. It is potentially important in the assessment of the overall burden and cumulative impact of chronic disease. This chapter reviews the concepts of life events, life transition, life goals concepts and what constitutes a long-term impact, essential background to this area. We also describe the relationship of the concept of MLCD with the concept of cumulative life course impairment. Chronic disease has long-term impact on patients' lives, particularly by influencing MLCDs related to career, job, relationships, education, having children and early retirement. We describe qualitative research carried out in Cardiff that has sought to give more detailed insight into what decisions constitute MLCDs, in patients both from dermatology and from several general medical disciplines. We have also proposed the MLCD Profile to measure the number of MLCDs that an individual patient may have experienced as being influenced by chronic disease. Adding the domain of MLCDs to how we think about the burden of disease experienced by an individual, could broaden understanding of the true extent of disease impact.

  15. Biologic History and the Cardinal Rule of Life

    NASA Astrophysics Data System (ADS)

    Schopf, J. W.

    2004-12-01

    In broad perspective, the history of life is remarkably static -- once set, a system that has changed little over all of geological time. The basic chemistry of living systems (CHONSP, and the monomers and polymers they compose), the genetics and cellular structure of life, even the ecologic division of the biologic world into "eaters" (heterotrophs) and "eatees" (autotrophs), are innovations all dating from the Archean that have carried over to the present. Throughout Earth history, biology has followed the Cardinal Rule of Life -- avoid change, never evolve at all! Biology maintains the status quo, opportunistically responding only if conditions change. Life's credo might well be "if it ain't broken, don't fix it." Of course, biomolecules do get "broken," by mutations, but living systems have many biochemical repair mechanisms. Evolution is a result of small changes that slip through unfixed. We see the results of evolution in the fossil record only because of the vastness, the true enormity, of geological time. What events punctuated this static underpinning to produce the modern living world? Only three, each in its own way shaping the course of life's history. The earliest, photosynthesis, freed life from dependence on foodstuffs made by nonbiologic processes. The advent of the advanced form of this process, oxygenic ("green plant") photosynthesis -- also an Archean innovation -- pumped oxygen into the environment (markedly increasing energy yields), "rusted the Earth" (evidenced by banded iron-formations), and, by ˜2,300 Ma ago, led to establishment of an aerobic-anaerobic ecosystem like that today. Not surprisingly, given the Cardinal Rule of Life, the inventors of this innovation, microbial cyanobacteria, evolved little over billions of years. The second major innovation was sex. In the modern world, this reproductive process is exhibited only by nucleated (eukaryotic) cells, derived from non-sexual eukaryotic ancestors. Although eukaryotes date from ˜2

  16. Survival on the ark: life history trends in captive parrots

    PubMed Central

    Young, Anna M.; Hobson, Elizabeth A.; Lackey, Laurie Bingaman; Wright, Timothy F.

    2011-01-01

    Members of the order Psittaciformes (parrots and cockatoos) are among the most long-lived and endangered avian species. Comprehensive data on lifespan and breeding are critical to setting conservation priorities, parameterizing population viability models, and managing captive and wild populations. To meet these needs, we analyzed 83, 212 life history records of captive birds from the International Species Information System and calculated lifespan and breeding parameters for 260 species of parrots (71% of extant species). Species varied widely in lifespan, with larger species generally living longer than smaller ones. The highest maximum lifespan recorded was 92 years in Cacatua moluccensis, but only 11 other species had a maximum lifespan over 50 years. Our data indicate that while some captive individuals are capable of reaching extraordinary ages, median lifespans are generally shorter than widely assumed, albeit with some increase seen in birds presently held in zoos. Species that lived longer and bred later in life tended to be more threatened according to IUCN classifications. We documented several individuals of multiple species that were able to breed for more than two decades, but the majority of clades examined had much shorter active reproduction periods. Post-breeding periods were surprisingly long and in many cases surpassed the duration of active breeding. Our results demonstrate the value of the ISIS database to estimate life history data for an at-risk taxon that is difficult to study in the wild, and provide life history data that is crucial for predictive modeling of future species endangerment and proactively managing captive populations of parrots. PMID:22389582

  17. Life history trade-offs imposed by dragline use in two money spiders.

    PubMed

    Bonte, Dries; Verduyn, Lieselot; Braeckman, Bart P

    2016-01-01

    Trade-offs among life history traits are central to understanding the limits of adaptations to stress. In animals, virtually all decisions taken during life are expected to have downstream consequences. To what degree rare, but energy-demanding, decisions carry over to individual performance is rarely studied in arthropods. We used spiders as a model system to test how single investments in silk use - for dispersal or predator escape - affect individual performance. Silk produced for safe lines and as threads for ballooning is of the strongest kind and is energetically costly, especially when resources are limited. We induced dragline spinning in two species of money spider at similar quantities to that under natural conditions and tested trade-offs with lifespan and egg sac production under unlimited prey availability and a dietary restriction treatment. We demonstrate strong trade-offs between dragline spinning and survival and fecundity. Survival trade-offs were additive to those imposed by the dietary treatment, but a reduction in eggs produced after silk use was only prevalent under conditions where food was restricted during the spider's life. Because draglines are not recycled after their use for dispersal or predator escape, their spinning incurs substantial fitness costs in dispersal, especially in environments with prey limitation. Rare but energetically costly decisions related to dispersal or predator escape may thus carry over to adult performance and explain phenotypic heterogeneity in natural populations.

  18. The history of life and death: a 'spiritual' history from invisible matter to prolongation of life.

    PubMed

    Gemelli, Benedino

    2012-01-01

    Over a long period of time, particularly from the nineteenth century on, Francis Bacon's philosophy has been interpreted as centred on the Novum organum and focused on the role that a well-organized method may play in securing a reliable knowledge of nature. In fact, if we examine Bacon's oeuvre as a whole, including some recent manuscript findings (De vijs mortis), we can safely argue that the issues addressed in the Novum organum represent only a part of Bacon's agenda, and not even the most important ones. By contrast, it is apparent that, from the very beginning of his investigations, he emphasized the central role of medicine, the need to establish new approaches in the study of the vital functions and the importance of promoting new discoveries in the medical field, not so much to find a cure for the many illnesses that plagued mankind as to prolong human life. In this sense, Historia vitae et mortis plays a central role in Bacon's programme to extend human knowledge and power, for, in his opinion, human beings could recover their lost ability to live a long and healthy life by embarking on careful investigations of nature. Far from being a purely descriptive or abstract exercise, Bacon's historia can therefore be seen as an operative tool to attain some of mankind's basic aims.

  19. Frustration influences impact of history and disciplinary attitudes on physical discipline decision making.

    PubMed

    Russa, Mary B; Rodriguez, Christina M; Silvia, Paul J

    2014-01-01

    Although intergenerational patterns of punitive physical punishment garner considerable research attention, the mechanisms by which historical, cognitive, and contextual factors interplay to influence disciplinary responding remains poorly understood. Disciplinary attitudes have been shown to mediate the association between disciplinary history and disciplinary responding. The present study investigated whether frustration influences these mediation effects. Half of a sample of 330 undergraduates was randomly assigned to frustration induction. Structural equation modeling confirmed that, for participants in the frustration condition, the relation between disciplinary history and physical discipline decision-making was fully mediated by attitudes approving physical discipline. In contrast, for respondents in the no-frustration condition, the pathway from disciplinary history to discipline decision-making was only partially mediated by attitudes. Under conditions of frustration, attitudes may become a more central means by which personal disciplinary history is associated with disciplinary decision-making.

  20. Effects of Harsh and Unpredictable Environments in Adolescence on Development of Life History Strategies

    PubMed Central

    Figueredo, Aurelio José; Ellis, Bruce J.

    2010-01-01

    The National Longitudinal Study of Adolescent Health data were used to test predictions from life history theory. We hypothesized that (1) in young adulthood an emerging life history strategy would exist as a common factor underlying many life history traits (e.g., health, relationship stability, economic success), (2) both environmental harshness and unpredictability would account for unique variance in expression of adolescent and young adult life history strategies, and (3) adolescent life history traits would predict young adult life history strategy. These predictions were supported. The current findings suggest that the environmental parameters of harshness and unpredictability have concurrent effects on life history development in adolescence, as well as longitudinal effects into young adulthood. In addition, life history traits appear to be stable across developmental time from adolescence into young adulthood. PMID:20634914

  1. Issues Using the Life History Calendar in Disability Research

    PubMed Central

    Scott, Tiffany N.; Harrison, Tracie

    2011-01-01

    Background Overall, there is a dearth of research reporting mixed-method data collection procedures using the LHC within disability research. Objective This report provides practical knowledge on use of the life history calendar (LHC) from the perspective of a mixed-method life history study of mobility impairment situated within a qualitative paradigm. Methods In this paper the method related literature referring to the LHC was reviewed along with its epistemological underpinnings. Further, the uses of the LHC in disability research were illustrated using preliminary data from reports of disablement in Mexican American and Non-Hispanic White women with permanent mobility impairment. Results From our perspective, the LHC was most useful when approached from an interpretive paradigm when gathering data from women of varied ethnic and socioeconomic strata. While we found the LHC the most useful tool currently available for studying disablement over the life course, there were challenges associated with its use. The LHC required extensive interviewer training. In addition, large segments of time were needed for completion depending on the type of participant responses. Conclusions Researchers planning to conduct a disability study may find our experience using the LHC valuable for anticipating issues that may arise when the LHC is used in mixed-method research. PMID:22014674

  2. Design decisions from the history of the EUVE science payload

    NASA Technical Reports Server (NTRS)

    Marchant, W.

    1993-01-01

    Some of the design issues that arose during the development of the EUVE science payload and solutions to the problems involved are examined. In particular, attention is given to the use of parallel and serial busses, the selection of the the ROM approach for software storage and execution, implementation of memory error detection and correction, and the selection of command structures. The early design decisions paid off in the timely delivery of the scientific payload and in the successful completion of the survey phase of the EUVE science mission.

  3. Corticosterone, testosterone and life-history strategies of birds.

    PubMed

    Hau, Michaela; Ricklefs, Robert E; Wikelski, Martin; Lee, Kelly A; Brawn, Jeffrey D

    2010-10-22

    Steroid hormones have similar functions across vertebrates, but circulating concentrations can vary dramatically among species. We examined the hypothesis that variation in titres of corticosterone (Cort) and testosterone (T) is related to life-history traits of avian species. We predicted that Cort would reach higher levels under stress in species with higher annual adult survival rates since Cort is thought to promote physiological and behavioural responses that reduce risk to the individual. Conversely, we predicted that peak T during the breeding season would be higher in short-lived species with high mating effort as this hormone is known to promote male fecundity traits. We quantified circulating hormone concentrations and key life-history traits (annual adult survival rate, breeding season length, body mass) in males of free-living bird species during the breeding season at a temperate site (northern USA) and a tropical site (central Panama). We analysed our original data by themselves, and also combined with published data on passerine birds to enhance sample size. In both approaches, variation in baseline Cort (Cort0) among species was inversely related to breeding season length and body mass. Stress-induced corticosterone (MaxCort) also varied inversely with body mass and, as predicted, also varied positively with annual adult survival rates. Furthermore, species from drier and colder environments exhibited lower MaxCort than mesic and tropical species; T was lowest in species from tropical environments. These findings suggest that Cort0, MaxCort and T modulate key vertebrate life-history responses to the environment, with Cort0 supporting energetically demanding processes, MaxCort promoting survival and T being related to mating success.

  4. Life history and the evolution of parental care.

    PubMed

    Klug, Hope; Bonsall, Michael B

    2010-03-01

    Patterns of parental care are strikingly diverse in nature, and parental care is thought to have evolved repeatedly multiple times. Surprisingly, relatively little is known about the most general conditions that lead to the origin of parental care. Here, we use a theoretical approach to explore the basic life-history conditions (i.e., stage-specific mortality and maturation rates, reproductive rates) that are most likely to favor the evolution of some form of parental care from a state of no care. We focus on parental care of eggs and eggs and juveniles and consider varying magnitudes of the benefits of care. Our results suggest that parental care can evolve under a range of life-history conditions, but in general will be most strongly favored when egg death rate in the absence of care is high, juvenile survival in the absence of care is low (for the scenario in which care extends into the juvenile stage), adult death rate is relatively high, egg maturation rate is low, and the duration of the juvenile stage is relatively short. Additionally, parental care has the potential to be favored at a broad range of adult reproductive rates. The relative importance of these life-history conditions in favoring or limiting the evolution of care depends on the magnitude of the benefits of care, the relationship between initial egg allocation and subsequent offspring survival, and whether care extends into the juvenile stage. The results of our model provide a general set of predictions regarding when we would expect parental care to evolve from a state of no care, and in conjunction with other work on the topic, will enhance our understanding of the evolutionary dynamics of parental care and facilitate comparative analyses.

  5. Robin's Story: Life History of an Exemplary American Female Physical Education Teacher

    ERIC Educational Resources Information Center

    Cazers, Gunars; Curtner-Smith, Matthew D.

    2017-01-01

    Purpose: The purpose was to construct the life history of Robin, an exemplary female physical educator, to hear her voice, and to explore ways in which she experienced marginalization. Few life histories of exemplary physical educators have been recounted. Method: Robin's life history was investigated in light of the theory of occupational…

  6. Early-Life Characteristics, Psychiatric History, and Cognition Trajectories in Later Life

    ERIC Educational Resources Information Center

    Brown, Maria Teresa

    2010-01-01

    Purpose of the Study: Although considerable attention has been paid to the relationship between later-life depression and cognitive function, the relationship between a history of psychiatric problems and cognitive function is not very well documented. Few studies of relationships between childhood health, childhood disadvantage, and cognitive…

  7. Early-Life Characteristics, Psychiatric History, and Cognition Trajectories in Later Life

    ERIC Educational Resources Information Center

    Brown, Maria Teresa

    2010-01-01

    Purpose of the Study: Although considerable attention has been paid to the relationship between later-life depression and cognitive function, the relationship between a history of psychiatric problems and cognitive function is not very well documented. Few studies of relationships between childhood health, childhood disadvantage, and cognitive…

  8. "Ant" and "grasshopper" life-history strategies in Saccharomyces cerevisiae.

    PubMed

    Spor, Aymé; Wang, Shaoxiao; Dillmann, Christine; de Vienne, Dominique; Sicard, Delphine

    2008-02-13

    From the evolutionary and ecological points of view, it is essential to distinguish between the genetic and environmental components of the variability of life-history traits and of their trade-offs. Among the factors affecting this variability, the resource uptake rate deserves particular attention, because it depends on both the environment and the genetic background of the individuals. In order to unravel the bases of the life-history strategies in yeast, we grew a collection of twelve strains of Saccharomyces cerevisiae from different industrial and geographical origins in three culture media differing for their glucose content. Using a population dynamics model to fit the change of population size over time, we estimated the intrinsic growth rate (r), the carrying capacity (K), the mean cell size and the glucose consumption rate per cell. The life-history traits, as well as the glucose consumption rate, displayed large genetic and plastic variability and genetic-by-environment interactions. Within each medium, growth rate and carrying capacity were not correlated, but a marked trade-off between these traits was observed over the media, with high K and low r in the glucose rich medium and low K and high r in the other media. The cell size was tightly negatively correlated to carrying capacity in all conditions. The resource consumption rate appeared to be a clear-cut determinant of both the carrying capacity and the cell size in all media, since it accounted for 37% to 84% of the variation of those traits. In a given medium, the strains that consume glucose at high rate have large cell size and low carrying capacity, while the strains that consume glucose at low rate have small cell size but high carrying capacity. These two contrasted behaviors may be metaphorically defined as "ant" and "grasshopper" strategies of resource utilization. Interestingly, a strain may be "ant" in one medium and "grasshopper" in another. These life-history strategies are discussed

  9. Life-history strategy determines constraints on immune function.

    PubMed

    Parker, Benjamin J; Barribeau, Seth M; Laughton, Alice M; Griffin, Lynn H; Gerardo, Nicole M

    2017-05-01

    Determining the factors governing investment in immunity is critical to understanding host-pathogen ecological and evolutionary dynamics. Studies often consider disease resistance in the context of life-history theory, with the expectation that investment in immunity will be optimized in anticipation of disease risk. Immunity, however, is constrained by context-dependent fitness costs. How the costs of immunity vary across life-history strategies has yet to be considered. Pea aphids are typically unwinged but produce winged offspring in response to high population densities and deteriorating conditions. This is an example of polyphenism, a strategy used by many organisms to adjust to environmental cues. The goal of this study was to examine the relationship between the fitness costs of immunity, pathogen resistance and the strength of an immune response across aphid morphs that differ in life-history strategy but are genetically identical. We measured fecundity of winged and unwinged aphids challenged with a heat-inactivated fungal pathogen, and found that immune costs are limited to winged aphids. We hypothesized that these costs reflect stronger investment in immunity in anticipation of higher disease risk, and that winged aphids would be more resistant due to a stronger immune response. However, producing wings is energetically expensive. This guided an alternative hypothesis - that investing resources into wings could lead to a reduced capacity to resist infection. We measured survival and pathogen load after live fungal infection, and we characterized the aphid immune response to fungi by measuring immune cell concentration and gene expression. We found that winged aphids are less resistant and mount a weaker immune response than unwinged aphids, demonstrating that winged aphids pay higher costs for a less effective immune response. Our results show that polyphenism is an understudied factor influencing the expression of immune costs. More generally, our work

  10. Opposing history effect of preceding decision and action in the free choice of saccade direction.

    PubMed

    Mochizuki, Kei; Funahashi, Shintaro

    2014-08-15

    When we act voluntarily, we make a decision to do so prior to the actual execution. However, because of the strong tie between decision and action, it has been difficult to dissociate these two processes in an animal's free behavior. In the present study, we tried to characterize the differences in these processes on the basis of their unique history effect. Using simple eye movement tasks in which the direction of a saccade was either instructed by a computer or freely chosen by the subject, we found that the preceding decision and action had different effects on the animal's subsequent behavior. While choosing a direction (previous decision) produced a positive history effect that prompted the choice of the same saccade direction, making a saccadic response to a direction (previous action) produced a negative history effect that discouraged the monkey from choosing the same direction. This result suggests that the history effect in sequential behavior reported in previous studies was a mixture of these two different components. Future studies on decision-making need to consider the importance of the distinction between decision and action in animal behavior.

  11. Increased Mortality Exposure within the Family Rather than Individual Mortality Experiences Triggers Faster Life-History Strategies in Historic Human Populations

    PubMed Central

    Störmer, Charlotte; Lummaa, Virpi

    2014-01-01

    Life History Theory predicts that extrinsic mortality risk is one of the most important factors shaping (human) life histories. Evidence from contemporary populations suggests that individuals confronted with high mortality environments show characteristic traits of fast life-history strategies: they marry and reproduce earlier, have shorter birth intervals and invest less in their offspring. However, little is known of the impact of mortality experiences on the speed of life histories in historical human populations with generally higher mortality risk, and on male life histories in particular. Furthermore, it remains unknown whether individual-level mortality experiences within the family have a greater effect on life-history decisions or family membership explains life-history variation. In a comparative approach using event history analyses, we study the impact of family versus individual-level effects of mortality exposure on two central life-history parameters, ages at first marriage and first birth, in three historical human populations (Germany, Finland, Canada). Mortality experience is measured as the confrontation with sibling deaths within the natal family up to an individual's age of 15. Results show that the speed of life histories is not adjusted according to individual-level mortality experiences but is due to family-level effects. The general finding of lower ages at marriage/reproduction after exposure to higher mortality in the family holds for both females and males. This study provides evidence for the importance of the family environment for reproductive timing while individual-level mortality experiences seem to play only a minor role in reproductive life history decisions in humans. PMID:24421897

  12. Movements of blue sharks (Prionace glauca) across their life history.

    PubMed

    Vandeperre, Frederic; Aires-da-Silva, Alexandre; Fontes, Jorge; Santos, Marco; Serrão Santos, Ricardo; Afonso, Pedro

    2014-01-01

    Spatial structuring and segregation by sex and size is considered to be an intrinsic attribute of shark populations. These spatial patterns remain poorly understood, particularly for oceanic species such as blue shark (Prionace glauca), despite its importance for the management and conservation of this highly migratory species. This study presents the results of a long-term electronic tagging experiment to investigate the migratory patterns of blue shark, to elucidate how these patterns change across its life history and to assess the existence of a nursery area in the central North Atlantic. Blue sharks belonging to different life stages (n = 34) were tracked for periods up to 952 days during which they moved extensively (up to an estimated 28.139 km), occupying large parts of the oceanic basin. Notwithstanding a large individual variability, there were pronounced differences in movements and space use across the species' life history. The study provides strong evidence for the existence of a discrete central North Atlantic nursery, where juveniles can reside for up to at least 2 years. In contrast with previously described nurseries of coastal and semi-pelagic sharks, this oceanic nursery is comparatively vast and open suggesting that shelter from predators is not its main function. Subsequently, male and female blue sharks spatially segregate. Females engage in seasonal latitudinal migrations until approaching maturity, when they undergo an ontogenic habitat shift towards tropical latitudes. In contrast, juvenile males generally expanded their range southward and apparently displayed a higher degree of behavioural polymorphism. These results provide important insights into the spatial ecology of pelagic sharks, with implications for the sustainable management of this heavily exploited shark, especially in the central North Atlantic where the presence of a nursery and the seasonal overlap and alternation of different life stages coincides with a high fishing

  13. Movements of Blue Sharks (Prionace glauca) across Their Life History

    PubMed Central

    Vandeperre, Frederic; Aires-da-Silva, Alexandre; Fontes, Jorge; Santos, Marco; Serrão Santos, Ricardo; Afonso, Pedro

    2014-01-01

    Spatial structuring and segregation by sex and size is considered to be an intrinsic attribute of shark populations. These spatial patterns remain poorly understood, particularly for oceanic species such as blue shark (Prionace glauca), despite its importance for the management and conservation of this highly migratory species. This study presents the results of a long-term electronic tagging experiment to investigate the migratory patterns of blue shark, to elucidate how these patterns change across its life history and to assess the existence of a nursery area in the central North Atlantic. Blue sharks belonging to different life stages (n = 34) were tracked for periods up to 952 days during which they moved extensively (up to an estimated 28.139 km), occupying large parts of the oceanic basin. Notwithstanding a large individual variability, there were pronounced differences in movements and space use across the species' life history. The study provides strong evidence for the existence of a discrete central North Atlantic nursery, where juveniles can reside for up to at least 2 years. In contrast with previously described nurseries of coastal and semi-pelagic sharks, this oceanic nursery is comparatively vast and open suggesting that shelter from predators is not its main function. Subsequently, male and female blue sharks spatially segregate. Females engage in seasonal latitudinal migrations until approaching maturity, when they undergo an ontogenic habitat shift towards tropical latitudes. In contrast, juvenile males generally expanded their range southward and apparently displayed a higher degree of behavioural polymorphism. These results provide important insights into the spatial ecology of pelagic sharks, with implications for the sustainable management of this heavily exploited shark, especially in the central North Atlantic where the presence of a nursery and the seasonal overlap and alternation of different life stages coincides with a high fishing

  14. Life history linked to immune investment in developing amphibians

    PubMed Central

    Woodhams, Douglas C.; Bell, Sara C.; Bigler, Laurent; Caprioli, Richard M.; Chaurand, Pierre; Lam, Brianna A.; Reinert, Laura K.; Stalder, Urs; Vazquez, Victoria M.; Schliep, Klaus; Hertz, Andreas; Rollins-Smith, Louise A.

    2016-01-01

    The broad diversity of amphibian developmental strategies has been shaped, in part, by pathogen pressure, yet trade-offs between the rate of larval development and immune investment remain poorly understood. The expression of antimicrobial peptides (AMPs) in skin secretions is a crucial defense against emerging amphibian pathogens and can also indirectly affect host defense by influencing the composition of skin microbiota. We examined the constitutive or induced expression of AMPs in 17 species at multiple life-history stages. We found that AMP defenses in tadpoles of species with short larval periods (fast pace of life) were reduced in comparison with species that overwinter as tadpoles and grow to a large size. A complete set of defensive peptides emerged soon after metamorphosis. These findings support the hypothesis that species with a slow pace of life invest energy in AMP production to resist potential pathogens encountered during the long larval period, whereas species with a fast pace of life trade this investment in defense for more rapid growth and development. PMID:27928507

  15. Life history and the early origins of health differentials.

    PubMed

    Worthman, Carol M; Kuzara, Jennifer

    2005-01-01

    Current epidemiologic models concerning the fetal origins of later health risk are evaluated from the perspectives of evolutionary and developmental biology. Claims of adaptive value for and biological status of fetal programming are critically examined. Life history theory is applied to identify key trade-offs in adaptive strategies that constrain developmental design to use information from the environment to guide ontogeny and establish cost-benefit trade-offs that weigh early survival advantage against remote or unlikely future costs. Expectable environments of evolutionary adaptedness, particularly of gestation, are characterized and their impact on human adaptive design discussed. The roles of neuroendocrine mechanisms in scaffolding life course development, negotiating ongoing cost-benefit trade-offs, and mediating their long-term impacts on function and health are reviewed in detail. Overviews of gestational biology and the postnatal physiologic, cognitive-affective, and behavioral effects of gestational stress identify a shared central role for the hypothalamic-pituitary-adrenal (HPA) axis. Rather than merely mediating stress responses, the axis emerges an agent of resource allocation that draws a common thread among conditions of gestation, postnatal environments, and functional and health-related outcomes. The preponderance of evolutionary and developmental analysis identifies environments as agents on both sides of the health risk equation, by influencing vulnerabilities and capacities established in early and later life course development, and determining exposures and demands encountered over the life course. (c) 2004 Wiley-Liss, Inc.

  16. Life history linked to immune investment in developing amphibians.

    PubMed

    Woodhams, Douglas C; Bell, Sara C; Bigler, Laurent; Caprioli, Richard M; Chaurand, Pierre; Lam, Brianna A; Reinert, Laura K; Stalder, Urs; Vazquez, Victoria M; Schliep, Klaus; Hertz, Andreas; Rollins-Smith, Louise A

    2016-01-01

    The broad diversity of amphibian developmental strategies has been shaped, in part, by pathogen pressure, yet trade-offs between the rate of larval development and immune investment remain poorly understood. The expression of antimicrobial peptides (AMPs) in skin secretions is a crucial defense against emerging amphibian pathogens and can also indirectly affect host defense by influencing the composition of skin microbiota. We examined the constitutive or induced expression of AMPs in 17 species at multiple life-history stages. We found that AMP defenses in tadpoles of species with short larval periods (fast pace of life) were reduced in comparison with species that overwinter as tadpoles and grow to a large size. A complete set of defensive peptides emerged soon after metamorphosis. These findings support the hypothesis that species with a slow pace of life invest energy in AMP production to resist potential pathogens encountered during the long larval period, whereas species with a fast pace of life trade this investment in defense for more rapid growth and development.

  17. Life histories of symbiotic rhizobia and mycorrhizal fungi.

    PubMed

    Denison, R Ford; Kiers, E Toby

    2011-09-27

    Research on life history strategies of microbial symbionts is key to understanding the evolution of cooperation with hosts, but also their survival between hosts. Rhizobia are soil bacteria known for fixing nitrogen inside legume root nodules. Arbuscular mycorrhizal (AM) fungi are ubiquitous root symbionts that provide plants with nutrients and other benefits. Both kinds of symbionts employ strategies to reproduce during symbiosis using host resources; to repopulate the soil; to survive in the soil between hosts; and to find and infect new hosts. Here we focus on the fitness of the microbial symbionts and how interactions at each of these stages has shaped microbial life-history strategies. During symbiosis, microbial fitness could be increased by diverting more resources to individual reproduction, but that may trigger fitness-reducing host sanctions. To survive in the soil, symbionts employ sophisticated strategies, such as persister formation for rhizobia and reversal of spore germination by mycorrhizae. Interactions among symbionts, from rhizobial quorum sensing to fusion of genetically distinct fungal hyphae, increase adaptive plasticity. The evolutionary implications of these interactions and of microbial strategies to repopulate and survive in the soil are largely unexplored.

  18. Genetic and life-history consequences of extreme climate events.

    PubMed

    Vincenzi, Simone; Mangel, Marc; Jesensek, Dusan; Garza, John Carlos; Crivelli, Alain J

    2017-02-08

    Climate change is predicted to increase the frequency and intensity of extreme climate events. Tests on empirical data of theory-based predictions on the consequences of extreme climate events are thus necessary to understand the adaptive potential of species and the overarching risks associated with all aspects of climate change. We tested predictions on the genetic and life-history consequences of extreme climate events in two populations of marble trout Salmo marmoratus that have experienced severe demographic bottlenecks due to flash floods. We combined long-term field and genotyping data with pedigree reconstruction in a theory-based framework. Our results show that after flash floods, reproduction occurred at a younger age in one population. In both populations, we found the highest reproductive variance in the first cohort born after the floods due to a combination of fewer parents and higher early survival of offspring. A small number of parents allowed for demographic recovery after the floods, but the genetic bottleneck further reduced genetic diversity in both populations. Our results also elucidate some of the mechanisms responsible for a greater prevalence of faster life histories after the extreme event. © 2017 The Author(s).

  19. Cognitive ability influences reproductive life history variation in the wild.

    PubMed

    Cole, Ella F; Morand-Ferron, Julie; Hinks, Amy E; Quinn, John L

    2012-10-09

    Cognition has been studied intensively for several decades, but the evolutionary processes that shape individual variation in cognitive traits remain elusive [1-3]. For instance, the strength of selection on a cognitive trait has never been estimated in a natural population, and the possibility that positive links with life history variation [1-5] are mitigated by costs [6] or confounded by ecological factors remains unexplored in the wild. We assessed novel problem-solving performance in 468 wild great tits Parus major temporarily taken into captivity and subsequently followed up their reproductive performance in the wild. Problem-solver females produced larger clutches than nonsolvers. This benefit did not arise because solvers timed their breeding better, occupied better habitats, or compromised offspring quality or their own survival. Instead, foraging range size and day length were relatively small and short, respectively, for solvers, suggesting that they were more efficient at exploiting their environment. In contrast to the positive effect on clutch size, problem solvers deserted their nests more often, leading to little or no overall selection on problem-solving performance. Our results are consistent with the idea that variation in cognitive ability is shaped by contrasting effects on different life history traits directly linked to fitness [1, 3].

  20. Life history, immunity, Peto's paradox and tumours in birds.

    PubMed

    Møller, A P; Erritzøe, J; Soler, J J

    2017-05-01

    Cancer and tumours may evolve in response to life-history trade-offs between growth and duration of development on one hand, and between growth and maintenance of immune function on the other. Here, we tested whether (i) bird species with slow developmental rates for their body size experience low incidence of tumours because slow development allows for detection of rapid proliferation of cell lineages. We also test whether (ii) species with stronger immune response during development are more efficient at detecting tumour cells and hence suffer lower incidence of tumours. Finally, we tested Peto's paradox, that there is a positive relationship between tumour incidence and body mass. We used information on developmental rates and body mass from the literature and of tumour incidence (8468 birds) and size of the bursa of Fabricius for 7659 birds brought to a taxidermist in Denmark. We found evidence of the expected negative relationship between incidence of tumours and developmental rates and immunity after controlling for the positive association between tumour incidence and body size. These results suggest that evolution has modified the incidence of tumours in response to life history and that Peto's paradox may be explained by covariation between body mass, developmental rates and immunity. © 2017 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2017 European Society For Evolutionary Biology.

  1. Sexual systems and life history of barnacles: a theoretical perspective.

    PubMed

    Yamaguchi, Sachi; Charnov, Eric L; Sawada, Kota; Yusa, Yoichi

    2012-09-01

    Thoracican barnacles show one of the most diverse sexual systems in animals: hermaphroditism, dioecy (males and females), and androdioecy (males and hermaphrodites). In addition, when present, male barnacles are very small and are called "dwarf males". The diverse sexual systems and male dwarfism in this taxon have attracted both theoretical and empirical biologists. In this article, we review the theoretical studies on barnacles' sexual systems in the context of sex allocation and life history theories. We first introduce the sex allocation models by Charnov, especially in relation to the mating group size, and a new expansion of his models is also proposed. We then explain three studies by Yamaguchi et al., who have studied the interaction between sex allocation and life history in barnacles. These studies consistently showed that limited mating opportunity favors androdioecy and dioecy over hermaphroditism. In addition, other factors, such as rates of survival and availability of food, are also important. We discuss the importance of empirical studies testing these predictions and how empirical studies interact with theoretical constructs.

  2. Seasonal variation in life history traits in two Drosophila species.

    PubMed

    Behrman, E L; Watson, S S; O'Brien, K R; Heschel, M S; Schmidt, P S

    2015-09-01

    Seasonal environmental heterogeneity is cyclic, persistent and geographically widespread. In species that reproduce multiple times annually, environmental changes across seasonal time may create different selection regimes that may shape the population ecology and life history adaptation in these species. Here, we investigate how two closely related species of Drosophila in a temperate orchard respond to environmental changes across seasonal time. Natural populations of Drosophila melanogaster and Drosophila simulans were sampled at four timepoints from June through November to assess seasonal change in fundamental aspects of population dynamics as well as life history traits. D. melanogaster exhibit pronounced change across seasonal time: early in the season, the population is inferred to be uniformly young and potentially represents the early generation following overwintering survivorship. D. melanogaster isofemale lines derived from the early population and reared in a common garden are characterized by high tolerance to a variety of stressors as well as a fast rate of development in the laboratory environment that declines across seasonal time. In contrast, wild D. simulans populations were inferred to be consistently heterogeneous in age distribution across seasonal collections; only starvation tolerance changed predictably over seasonal time in a parallel manner as in D. melanogaster. These results suggest fundamental differences in population and evolutionary dynamics between these two taxa associated with seasonal heterogeneity in environmental parameters and associated selection pressures.

  3. Effects of Aquatic Insect Life History Patterns on Bioassessments

    NASA Astrophysics Data System (ADS)

    Fend, S. V.; Carter, J. L.; Weissich, P.

    2005-05-01

    Aquatic insect populations vary greatly over an annual cycle. Nevertheless, given practical constraints, biomonitoring programs focusing on these animals typically have broad sampling seasons (index periods). Stated or implicit assumptions are 1) replacement by different populations with similar environmental tolerance occurs, and/or 2) metrics can be generated that are sufficiently robust or can be seasonally adjusted. To support tests of seasonal variability in macroinvertebrate metrics, we analyzed life history patterns of dominant EPT species in 3 regulated and 3 non-regulated streams. Population peaks (recruitment periods) of taxa numerically dominant in both stream types (Baetis tricaudatus, Hydropsyche spp., and Malenka cf. californica) were asynchronous, even within streamflow category. Populations of some intolerant taxonomic groups occurring in non-regulated streams (e.g., Ephemerellidae) were restricted to the fall-spring period. Other groups (e.g., Rhyacophilidae, Heptageniidae) included species that maintained high summer populations. Therefore, defining an index period for all streams in a given area is difficult because life history patterns are often site-specific. Seasonal adjustments based on statistical properties of derived metrics may be useful for describing conditions over a large area but at the site level, behavior of individual populations may need to be considered for an accurate assessment.

  4. Life history and locomotion in Cebus capucinus and Alouatta palliata.

    PubMed

    Bezanson, Michelle

    2009-11-01

    As an individual matures from birth to adulthood, many factors may influence the positional repertoire. The biological and behavioral changes that accompany a growing individual are expected to influence foraging strategy, social status and interaction, diet, predator avoidance strategies, and ultimately positional behavior as a behavioral link between anatomy and the environment. In this work, positional behavior is considered as an important feature of life history in juvenile and adult white-faced capuchins (Cebus capucinus) and mantled howling monkeys (Alouatta palliata) inhabiting the same tropical forest in Costa Rica. During growth and development ontogenetic changes in body size, limb proportions, and motor skills are likely to influence locomotion and posture through the arboreal canopy. I collected data on positional behavior, activity, branch size, branch angle, and crown location during a 12-month period at Estación Biológica La Suerte in northeastern Costa Rica. Life history timing and differences in rates of growth did not predictably influence the development of adultlike positional behaviors in Cebus and Alouatta. Young Cebus resembled the adult pattern of positional behavior by 6 months of age while howlers exhibited significant differences in several positional behavior categories through 24 months of age. The positional repertoire of both species revealed similarities in the types of modes used during feed/forage and travel in juveniles and adults. Data presented here suggest that the environment exerts different pressures on growing Cebus and Alouatta that may relate to diet, energy expenditure, foraging skill, and/or social learning.

  5. Seasonal variation in life history traits in two Drosophila species

    PubMed Central

    BEHRMAN, E. L.; WATSON, S. S.; O'BRIEN, K. R.; HESCHEL, M. S.; SCHMIDT, P. S.

    2016-01-01

    Seasonal environmental heterogeneity is cyclic, persistent and geographically widespread. In species that reproduce multiple times annually, environmental changes across seasonal time may create different selection regimes that may shape the population ecology and life history adaptation in these species. Here, we investigate how two closely related species of Drosophila in a temperate orchard respond to environmental changes across seasonal time. Natural populations of Drosophila melanogaster and Drosophila simulans were sampled at four timepoints from June through November to assess seasonal change in fundamental aspects of population dynamics as well as life history traits. D. melanogaster exhibit pronounced change across seasonal time: early in the season, the population is inferred to be uniformly young and potentially represents the early generation following overwintering survivorship. D. melanogaster isofemale lines derived from the early population and reared in a common garden are characterized by high tolerance to a variety of stressors as well as a fast rate of development in the laboratory environment that declines across seasonal time. In contrast, wild D. simulans populations were inferred to be consistently heterogeneous in age distribution across seasonal collections; only starvation tolerance changed predictably over seasonal time in a parallel manner as in D. melanogaster. These results suggest fundamental differences in population and evolutionary dynamics between these two taxa associated with seasonal heterogeneity in environmental parameters and associated selection pressures. PMID:26174167

  6. Ecology, Life History, and Management of Tropilaelaps Mites.

    PubMed

    de Guzman, Lilia I; Williams, Geoffrey R; Khongphinitbunjong, Kitiphong; Chantawannakul, Panuwan

    2017-03-15

    Parasitic mites are the major threat to the Western honey bee, Apis mellifera L. For much of the world, Varroa destructor Anderson & Trueman single-handedly inflicts unsurmountable problems to A. mellifera beekeeping. However, A. mellifera in Asia is also faced with another genus of destructive parasitic mite, Tropilaelaps. The life history of these two parasitic mites is very similar, and both have the same food requirements (i.e., hemolymph of developing brood). Hence, parasitism by Tropilaelaps spp., especially Tropilaelaps mercedesae and Tropilaelaps clareae, also results in death of immature brood or wing deformities in infested adult bees. The possible introduction of Tropilaelaps mites outside their current range heightens existing dilemmas brought by Varroa mites. In this review, we provide historic, as well as current information on the taxonomic status, life history, distribution and host range, diagnosis, and control of Tropilaelaps mites. Because the biology of Tropilaelaps mites is not well known, we also suggest areas of research that demand immediate attention. Any biological information about Tropilaelaps mites will provide useful information for the development of control measures against them.

  7. Metabolite changes during the life history of Porphyra haitanensis.

    PubMed

    Wang, X; Zhao, P; Luo, Q; Yan, X; Xu, J; Chen, J; Chen, H

    2015-05-01

    Plant metabolomics is essentially the comprehensive analysis of complex metabolites of plant extracts. Metabolic fingerprinting is an important part of plant metabolomics research. In this study, metabolic fingerprinting of different stages of the life history of the red alga Porphyra haitanensis was performed. The stages included conchocelis filaments, sporangial branchlets, conchosporangia, discharged conchospores and conchosporangial branchlets after conchospore discharge. Metabolite extracts were analysed with ultra-performance liquid chromatography coupled with electrospray ionisation quadrupole-time of flight mass spectrometry. Analyses profiles were subjected to principal components analysis and orthogonal projection to latent structures discriminant analysis using the SIMCA-P software for biomarker selection and identification. Based on the MS/MS spectra and data from the literature, potential biomarkers, mainly of phosphatidylcholine and lysophosphatidylcholine, were identified. Identification of these biomarkers suggested that plasma membrane phospholipids underwent major changes during the life history of P. haitanensis. The levels of phosphatidylcholine and lysophosphatidylcholine increased in sporangial branchlets and decreased in discharged conchospores. Moreover, levels of sphingaine (d18:0) decreased in sporangial branchlets and increased in discharged conchospores, which indicates that membrane lipids were increasingly synthesised as energy storage in sporangial branchlets, while energy was consumed in sporangial branchlets to discharged conchospores. A metabolomic study of different growth phases of P. haitanensis will enhance our understanding of its physiology and ecology.

  8. Life-history evolution and mitogenomic phylogeny of caecilian amphibians.

    PubMed

    San Mauro, Diego; Gower, David J; Müller, Hendrik; Loader, Simon P; Zardoya, Rafael; Nussbaum, Ronald A; Wilkinson, Mark

    2014-04-01

    We analyze mitochondrial genomes to reconstruct a robust phylogenetic framework for caecilian amphibians and use this to investigate life-history evolution within the group. Our study comprises 45 caecilian mitochondrial genomes (19 of them newly reported), representing all families and 27 of 32 currently recognized genera, including some for which molecular data had never been reported. Support for all relationships in the inferred phylogenetic tree is high to maximal, and topology tests reject all investigated alternatives, indicating an exceptionally robust molecular phylogenetic framework of caecilian evolution consistent with current morphology-based supraspecific classification. We used the mitogenomic phylogenetic framework to infer ancestral character states and to assess correlation among three life-history traits (free-living larvae, viviparity, specialized pre-adult or vernal teeth), each of which occurs only in some caecilian species. Our results provide evidence that an ancestor of the Seychelles caecilians abandoned direct development and re-evolved a free-living larval stage. This study yields insights into the concurrent evolution of direct development and of vernal teeth in an ancestor of Teresomata that likely gave rise to skin-feeding (maternal dermatophagy) behavior and subsequently enabled evolution of viviparity, with skin feeding possibly a homologous precursor of oviduct feeding in viviparous caecilians.

  9. Life-history traits of the stone loach Barbatula barbatula.

    PubMed

    Vinyoles, D; de Sostoa, A; Franch, C; Maceda-Veiga, A; Casals, F; Caiola, N

    2010-07-01

    The life-history tactics of the stone loach Barbatula barbatula were studied in a Mediterranean-type climate stream (Matarranya River) located in the Ebro River basin (north-east Spain). Maximum observed ages were 2+ years in both sexes (1% of individuals), although only 0+ and 1+ year age groups were well represented. It is the lowest longevity reported for this species in its entire distribution. The seasonal growth period started in June and continued until November, but the pattern observed was different to northern populations. Barbatula barbatula in the Matarranya River was a multiple spawner, releasing small batches of oocytes between April and June. The fecundity of females was higher and the size of oocytes smaller in 1984 than in 1985. The relative fecundity (number of ripening and ripe oocytes g(-1) of fish) was lower than in northern European populations. The role of the particular environmental conditions of a Mediterranean stream was discussed in relation to the life-history tactics of B. barbatula.

  10. International collaboration in shared decision-making: the International Shared Decision Making (ISDM) conference history and prospects.

    PubMed

    Holmes-Rovner, Margaret

    2008-12-01

    Analyze the role of collaboration in the International Shared Decision Making organization (ISDM). Case study of the seven year history of ISDM as a professional network. The International Shared Decision Making meeting Conference (ISDM) has held four biennial meetings since its inception in 2001. It is a freestanding professional meeting, with no permanent institutional support and no formal governance structure. In both its history and its prospects, collaboration among attendees has been pivotal to its growth. It both attracts and holds its "members" through the strength of the relationships formed during and between meetings. Exchanges in ISDM are informational, collegial, and indirectly economic. ISDM's future rests on keeping all three functions healthy. It must maintain a focus on putting the shared decision making work first through becoming a "worknet". Technologies that promote shared decision making can then be assembled and developed that support transformation of health care. Innovative professional organizations need to develop their work through deliberate development of networking techniques to move innovation into practice.

  11. Population-specific life histories contribute to metapopulation viability

    USGS Publications Warehouse

    Halsey, Samniqueka J.; Bell, Timothy J.; McEachern, Kathryn; Pavlovic, Noel B.

    2016-01-01

    Restoration efforts can be improved by understanding how variations in life-history traits occur within populations of the same species living in different environments. This can be done by first understanding the demographic responses of natural occurring populations. Population viability analysis continues to be useful to species management and conservation with sensitivity analysis aiding in the understanding of population dynamics. In this study, using life-table response experiments and elasticity analyses, we investigated how population-specific life-history demographic responses contributed to the metapopulation viability of the Federally threatened Pitcher's thistle (Cirsium pitcheri). Specifically, we tested the following hypotheses: (1) Subpopulations occupying different environments within a metapopulation have independent demographic responses and (2) advancing succession results in a shift from a demographic response focused on growth and fecundity to one dominated by stasis. Our results showed that reintroductions had a positive contribution to the metapopulation growth rate as compared to native populations which had a negative contribution. We found no difference in succession on the contribution to metapopulation viability. In addition, we identified distinct population-specific contributions to metapopulation viability and were able to associate specific life-history demographic responses. For example, the positive impact of Miller High Dunes population on the metapopulation growth rate resulted from high growth contributions, whereas increased time of plant in stasis for the State Park Big Blowout population resulted in negative contributions. A greater understanding of how separate populations respond in their corresponding environment may ultimately lead to more effective management strategies aimed at reducing extinction risk. We propose the continued use of sensitivity analyses to evaluate population-specific demographic influences on

  12. Behavioural consistency and life history of Rana dalmatina tadpoles.

    PubMed

    Urszán, Tamás János; Török, János; Hettyey, Attila; Garamszegi, László Zsolt; Herczeg, Gábor

    2015-05-01

    The focus of evolutionary behavioural ecologists has recently turned towards understanding the causes and consequences of behavioural consistency, manifesting either as animal personality (consistency in a single behaviour) or behavioural syndrome (consistency across more behaviours). Behavioural type (mean individual behaviour) has been linked to life-history strategies, leading to the emergence of the integrated pace-of-life syndrome (POLS) theory. Using Rana dalmatina tadpoles as models, we tested if behavioural consistency and POLS could be detected during the early ontogenesis of this amphibian. We targeted two ontogenetic stages and measured activity, exploration and risk-taking in a common garden experiment, assessing both individual behavioural type and intra-individual behavioural variation. We observed that activity was consistent in all tadpoles, exploration only became consistent with advancing age and risk-taking only became consistent in tadpoles that had been tested, and thus disturbed, earlier. Only previously tested tadpoles showed trends indicative of behavioural syndromes. We found an activity-age at metamorphosis POLS in the previously untested tadpoles irrespective of age. Relative growth rate correlated positively with the intra-individual variation of activity of the previously untested older tadpoles. In previously tested older tadpoles, intra-individual variation of exploration correlated negatively and intra-individual variation of risk-taking correlated positively with relative growth rate. We provide evidence for behavioural consistency and POLS in predator- and conspecific-naive tadpoles. Intra-individual behavioural variation was also correlated to life history, suggesting its relevance for the POLS theory. The strong effect of moderate disturbance related to standard behavioural testing on later behaviour draws attention to the pitfalls embedded in repeated testing.

  13. Decisions at the end of life: Catholic tradition.

    PubMed

    Donovan, G Kevin

    1997-12-01

    Medical decisions regarding end-of-life care have undergone significant changes in recent decades, driven by changes in both medicine and society. Catholic tradition in medical ethics offers clear guidance in many issues, and a moral framework accessible to those who do not share the same faith as well as to members of its faith community. In some areas, a Catholic perspective can be seen clearly and confidently, such as in teachings on the permissibility of suicide and euthanasia. In others, such as withdrawal of nutrition and hydration, the Church does not yet speak with one voice and has not closed out the discussion. Yet, it is not in the teaching on individual issues that a Catholic moral tradition offers the most help and comfort, but in its account of what it means to lead a life in Christ, and to prepare for a Christian death. As in the problem of pain and suffering, it is the spiritual support more than the ethical guidance that helps both patients and physicians bear the unbearable and fathom the unfathomable.

  14. Salamander paedomorphosis: linking thyroid hormone to life history and life cycle evolution.

    PubMed

    Johnson, Carlena K; Voss, S Randal

    2013-01-01

    Many salamanders have biphasic life cycles with aquatic larval and terrestrial adult phases. In these species, the transition between phases-metamorphosis-requires thyroid hormone (TH) activation of transcriptional programs that cause regression of larval traits and development of adult traits. During salamander evolution, TH signaling pathways have been altered in biphasic species to yield paedomorphic salamanders that retain larval traits and attain sexual maturity in larval aquatic habitats. We review literature concerning the ecology, evolution, and hormonal regulation of metamorphic, paedomorphic, and facultative salamander life histories. We then discuss recent microarray results that detail gene expression signatures of metamorphosis and paedomorphosis, and genetic results that establish TH responsiveness as a continuous trait with a quantitative trait locus (QTL) basis. TH-responsive QTL from ambystomatid salamanders explain variation in metamorphic timing, expression of metamorphosis versus paedomorphosis, and adult fitness traits. We propose a model for salamander life history evolution that links adaptation to aquatic habitats with TH-responsive loci that pleiotropically alter metamorphic timing and adult body size. Future studies that adopt genetic and genomic approaches will further establish salamanders as ideal models for investigating TH signaling mechanisms that regulate postembryonic development and the expression of alternate life histories.

  15. Understanding life together: a brief history of collaboration in biology.

    PubMed

    Vermeulen, Niki; Parker, John N; Penders, Bart

    2013-09-01

    The history of science shows a shift from single-investigator 'little science' to increasingly large, expensive, multinational, interdisciplinary and interdependent 'big science'. In physics and allied fields this shift has been well documented, but the rise of collaboration in the life sciences and its effect on scientific work and knowledge has received little attention. Research in biology exhibits different historical trajectories and organisation of collaboration in field and laboratory - differences still visible in contemporary collaborations such as the Census of Marine Life and the Human Genome Project. We employ these case studies as strategic exemplars, supplemented with existing research on collaboration in biology, to expose the different motives, organisational forms and social dynamics underpinning contemporary large-scale collaborations in biology and their relations to historical patterns of collaboration in the life sciences. We find the interaction between research subject, research approach as well as research organisation influencing collaboration patterns and the work of scientists. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. Life history characteristics of diorhabda carinulata under various temperatures.

    PubMed

    Acharya, Kumud; Sueki, Sachiko; Conrad, Benjamin; Dudley, Tom L; Bean, Dan W; Osterberg, John C

    2013-06-01

    Tamarisk leaf beetles, Diorhabda spp., have been released in the western United States as a biological control agent for the invasive weed Tamarix spp. There have been a few studies on the life cycle, host preferences, and field observations of Diorhabda; however, their ecophysiological characteristics under various temperature regimes are not clearly understood. In this study, life history characteristics such as growth, fecundity, and mortality of Diorhabda Carinulata (Desbrochers), the species established in the Colorado River basin, were investigated under various temperatures. Beetles were housed at various temperatures (room, constant high, and variable high) and their life cycle from eggs to reproductive adult was observed. Body size at various larval and adult stages, as well as their developmental time decreased with increasing temperature. Between the two temperature treatments, beetles at diurnally fluctuating temperature (variable high treatment) grew slower and produced fewer eggs per clutch when compared with the constant high treatment. Despite smaller in size, beetles grew fastest at the constant high temperature and produced most eggs per clutch compared with the other two treatments. Overall, severely high temperatures seem to have a debilitating effect on Diorhabda at early larval stages with nearly 50% mortality. The study has potential implications for the tamarisk beetle biocontrol program in the southwestern United States.

  17. Eliciting regret improves decision making at the end of life.

    PubMed

    Djulbegovic, Benjamin; Tsalatsanis, Athanasios; Mhaskar, Rahul; Hozo, Iztok; Miladinovic, Branko; Tuch, Howard

    2016-11-01

    Management choices at the end of life are high-stake decisions fraught with emotions, chief among is regret. Our objective in this paper is to test the utility of a regret-based model to facilitate referral to hospice care while helping patients clarify their preferences on how they wish to spend the remaining days of their lives. A prospective cohort study that enrolled consecutive adult patients (n = 178) aware of the terminal nature of their disease. The patients were at the point in care where they had to decide between continuing potentially 'curative/life-prolonging' treatment (Rx) versus hospice care. Preferences were elicited using a Dual Visual Analog Scale regarding the level of regret of omission versus commission (RgO/RgC) towards hospice care and Rx. Each patient's RgO/RgC was contrasted against the predictive probability of death to suggest a management plan, which was then compared with the patient's actual choice. The probability of death was estimated using validated Palliative Performance Scale predictive model. Eighty-five percent (151/178) of patients agreed with the model's recommendations (p < 0.000001). Model predicted the actual choices for 72% (128/178) of patients (p < 0.00001). Logistic regression analysis showed that people who were initially inclined to be referred to hospice and were predicted to choose hospice over disease-directed treatment by the regret model have close to 98% probability of choosing hospice care at the end of their lives. No other factors (age, gender, race, educational status and pain level) affected their choice. Using regret to elicit choices in the end-of-life setting is both descriptively and prescriptively valid. People with terminal disease who are initially inclined to choose hospice and do not regret such a choice will select hospice care with high level of certainty. Copyright © 2016 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  18. Life history dependent morphometric variation in stream-dwelling Atlantic salmon

    USGS Publications Warehouse

    Letcher, B.H.

    2003-01-01

    The time course of morphometric variation among life histories for stream-dwelling Atlantic salmon (Salmo salar L.) parr (age-0+ to age-2+) was analyzed. Possible life histories were combinations of parr maturity status in the autumn (mature or immature) and age at outmigration (smolt at age-2+ or later age). Actual life histories expressed with enough fish for analysis in the 1997 cohort were immature/age-2+ smolt, mature/age-2 +smolt, and mature/age-2+ non-smolt. Tagged fish were assigned to one of the three life histories and digital pictures from the field were analyzed using landmark-based geometric morphometrics. Results indicated that successful grouping of fish according to life history varied with fish age, but that fish could be grouped before the actual expression of the life histories. By March (age-1+), fish were successfully grouped using a descriptive discriminant function and successful assignment ranged from 84 to 97% for the remainder of stream residence. A jackknife of the discriminant function revealed an average life history prediction success of 67% from age-1+ summer to smolting. Low sample numbers for one of the life histories may have limited prediction success. A MANOVA on the shape descriptors (relative warps) also indicated significant differences in shape among life histories from age-1+ summer through to smolting. Across all samples, shape varied significantly with size. Within samples, shape did not vary significantly with size for samples from December (age-0+) to May (age-1+). During the age-1+ summer however, shape varied significantly with size, but the relationship between shape and size was not different among life histories. In the autumn (age-1+) and winter (age-2+), life history differences explained a significant portion of the change in shape with size. Life history dependent morphometric variation may be useful to indicate the timing of early expressions of life history variation and as a tool to explore temporal and

  19. Beyond dichotomous life histories in partially migrating populations: cessation of anadromy in a long-lived fish.

    PubMed

    Bond, Morgan H; Miller, Jessica A; Quinn, Thomas P

    2015-07-01

    Across animal taxa, migration allows individuals to exploit habitats and resources that predictably vary seasonally in suitability. Theory predicts that the "decision" to migrate or not is shaped by the relative fitness costs and benefits of exhibiting a given life history. Adoption of a migratory strategy is widely thought to reflect a dichotomous outcome; individuals are either resident or migratory, and continue to exhibit this life history until death. In fishes, anadromy and freshwater residency represents a well-studied life history dichotomy. Resident individuals may adopt a migratory life history later in life, but migratory individuals are not known to abandon this pattern. Here, we investigated the fitness benefits, as measured by body size, of residency and anadromy in a salmonid fish, Dolly Varden, Salvelinus malma, in Alaska, and reveal a novel life history: cessation of migration by older, larger individuals. Otolith microchemical analysis of Dolly Varden showed that while most fish migrated to sea at least once in their lives, lifelong resident fish exist in streams with close proximity to the ocean. Moreover, the probability of seaward migration in any year of life decreased annually after an individual's fourth year, and no fish migrated after their eighth year, while the oldest fish were captured in their 11th year. Migration conferred a size advantage in young fish, but the size benefits of marine foraging declined in older fish, at which time fish increasingly "retired from anadromy." Additionally, measurement of both natal otolith chemistry and the gonadosomatic index indicated a continued contribution to lifetime fitness, rather than senescence, in retired individuals. We suggest that the novel life history of reversion to residency by older fish is viable because foraging opportunities are subsidized by the predictable annual supply of energy-rich eggs and carcasses of spawning Pacific salmon.

  20. Sex differences in the persistence of natal environmental effects on life histories.

    PubMed

    Wilkin, Teddy A; Sheldon, Ben C

    2009-12-15

    "Silver spoon" effects of early environments on adult characteristics and life-history trajectories are thought to be widespread among vertebrates and are important because they imply that environments can have cascading transgenerational effects. Here we test for such effects by using a sample of 5425 great tits (Parus major) for which both natal and breeding environments were known in detail. Female life histories were strongly coupled with breeding conditions, but we found little evidence for any persistent effects of the natal environment. In contrast, life span and breeding success in males were influenced by the quality of the environment in which they were raised. Potential explanations for persistent environmental effects in males, but not females, include differential sex allocation benefiting males from high-quality environments and phenotypic plasticity allowing females to optimize reproductive decisions to current conditions, hence masking any residual natal effects. Thus, in contrast to findings of much recent work, persistent effects of the early environment are not all-pervasive and may differ between the sexes within a single species, potentially leading to sex-differential selection. Further work should attempt to understand the conditions under which these transgenerational environmental effects are likely to occur.

  1. Family Communication about End-of-Life Decisions and the Enactment of the Decision-Maker Role

    PubMed Central

    Trees, April R.; Ohs, Jennifer E.; Murray, Meghan C.

    2017-01-01

    End-of-life (EOL) decisions in families are complex and emotional sites of family interaction necessitating family members coordinate roles in the EOL decision-making process. How family members in the United States enact the decision-maker role in EOL decision situations was examined through in-depth interviews with 22 individuals who participated in EOL decision-making for a family member. A number of themes emerged from the data with regard to the enactment of the decision-maker role. Families varied in how decision makers enacted the role in relation to collective family input, with consulting, informing and collaborating as different patterns of behavior. Formal family roles along with gender- and age-based roles shaped who took on the decision-maker role. Additionally, both family members and medical professionals facilitated or undermined the decision-maker’s role enactment. Understanding the structure and enactment of the decision-maker role in family interaction provides insight into how individuals and/or family members perform the decision-making role within a cultural context that values autonomy and self-determination in combination with collective family action in EOL decision-making. PMID:28590407

  2. Libraries of life: using life history books with depressed care home residents.

    PubMed

    Plastow, Nicola Ann

    2006-01-01

    Depression is a common, and often undetected, psychiatric disorder in geriatric care home residents. Reminiscence, an independent nursing therapy used by a variety of health and social care professionals, can prevent or reduce depression. This practice development project explored the use of reminiscence life history books as an interpersonal therapeutic tool with 3 depressed care-home residents living in residential care and skilled nursing facilities. The process of choosing to produce a book, assessment of capabilities, and methods of construction are described using 3 illustrative case studies. Three themes emerged: reviewing the past, accepting the present, and dreaming of an alternative future. This project demonstrated that life history books, tailored to individual needs and abilities, can facilitate reminiscence and reduce depression by increasing social interaction. The benefits to residents, their families, and care staff are discussed and the relevance to nursing practice highlighted.

  3. Preadult life history variation determines adult transcriptome expression

    PubMed Central

    Etges, William J.; de Oliveira, Cássia; Rajpurohit, Subhash; Gibbs, Allen G.

    2015-01-01

    Preadult determinants of adult fitness and behavior have been documented in a variety of organisms with complex life cycles, but little is known about expression patterns of genes underlying these adult traits. We explored the effects of differences in egg to adult development time on adult transcriptome and cuticular hydrocarbon variation in order to understand the nature of the genetic correlation between preadult development time and premating isolation between populations of Drosophila mojavensis reared in different host cactus environments. Transcriptome variation was analyzed separately in flies reared on each host and revealed that hundreds of genes in adults were differentially expressed (FDR P < 0.05) due to development time differences. For flies reared on pitaya agria cactus, longer preadult development times caused increased expression of genes in adults enriched for ribosome production, protein metabolism, chromatin remodeling, and regulation of alternate splicing and transcription. Baja California flies reared on organ pipe cactus showed fewer differentially expressed genes in adults due to longer preadult development time, but these were enriched for ATP synthesis and the TCA cycle. Mainland flies reared on organ pipe cactus with shorter development times showed increased transcription of genes enriched for mitochondria and energy production, protein synthesis, and glucose metabolism: adults with longer development times had increased expression of genes enriched for adult life span, cuticle proteins and ion binding, although most differentially expressed genes were unannotated. Differences due to population, sex, mating status, and their interactions were also assessed. Adult cuticular hydrocarbon profiles also showed shifts due to egg to adult development time, and were influenced by population and mating status. These results help to explain why preadult life history variation determines subsequent expression of the adult transcriptome along with

  4. Preadult life history variation determines adult transcriptome expression.

    PubMed

    Etges, William J; de Oliveira, Cássia; Rajpurohit, Subhash; Gibbs, Allen G

    2016-02-01

    Preadult determinants of adult fitness and behaviour have been documented in a variety of organisms with complex life cycles, but little is known about expression patterns of genes underlying these adult traits. We explored the effects of differences in egg-to-adult development time on adult transcriptome and cuticular hydrocarbon variation in order to understand the nature of the genetic correlation between preadult development time and premating isolation between populations of Drosophila mojavensis reared in different host cactus environments. Transcriptome variation was analysed separately in flies reared on each host and revealed that hundreds of genes in adults were differentially expressed (FDR P < 0.05) due to development time differences. For flies reared on pitaya agria cactus, longer preadult development times caused increased expression of genes in adults enriched for ribosome production, protein metabolism, chromatin remodelling and regulation of alternate splicing and transcription. Baja California flies reared on organ pipe cactus showed fewer differentially expressed genes in adults due to longer preadult development time, but these were enriched for ATP synthesis and the TCA cycle. Mainland flies reared on organ pipe cactus with shorter development times showed increased transcription of genes enriched for mitochondria and energy production, protein synthesis and glucose metabolism: adults with longer development times had increased expression of genes enriched for adult life span, cuticle proteins and ion binding, although most differentially expressed genes were unannotated. Differences due to population, sex, mating status and their interactions were also assessed. Adult cuticular hydrocarbon profiles also showed shifts due to egg-to-adult development time and were influenced by population and mating status. These results help to explain why preadult life history variation determines subsequent expression of the adult transcriptome along with

  5. Dynamics and life histories of northern ungulates in changing environments

    NASA Astrophysics Data System (ADS)

    Hendrichsen, D. K.

    2011-12-01

    Regional climate and local weather conditions can profoundly influence life history parameters (growth, survival, fecundity) and population dynamics in northern ungulates (Post and Stenseth 1999, Coulson et al. 2001). The influence is both direct, for example through reduced growth or survival (Aanes et al. 2000, Tyler et al. 2008), and indirect, for example through changes in resource distribution, phenology and quality, changes which subsequently influence consumer dynamics (Post et al. 2008). By comparing and contrasting data from three spatially independent populations of ungulates, I discuss how variation in local weather parameters and vegetation growth influence spatial and temporal dynamics through changes in life history parameters and/or behavioural dynamics. The data originate from long term (11-15 years) monitoring data from three populations of ungulates in one subarctic and two high Arctic sites; semi-domesticated reindeer (Rangifer tarandus tarandus) in northern Norway, Svalbard reindeer (R. t. platyrhynchus) on Spitsbergen and muskoxen (Ovibos moschatus) in Northeast Greenland. The results show that juvenile animals can be particularly vulnerable to changes in their environment, and that this is mirrored to different degrees in the spatio-temporal dynamics of the three populations. Adverse weather conditions, acting either directly or mediated through access to and quality of vegetation, experienced by young early in life, or even by their dams during pregnancy, can lead to reduced growth, lower survival and reduced reproductive performance later in life. The influence of current climatic variation, and the predictions of how local weather conditions may change over time, differs between the three sites, resulting in potentially different responses in the three populations. Aanes R, Saether BE and Øritsland NA. 2000. Fluctuations of an introduced population of Svalbard reindeer: the effects of density dependence and climatic variation. Ecography

  6. How Life History Can Sway the Fixation Probability of Mutants.

    PubMed

    Li, Xiang-Yi; Kurokawa, Shun; Giaimo, Stefano; Traulsen, Arne

    2016-07-01

    In this work, we study the effects of demographic structure on evolutionary dynamics when selection acts on reproduction, survival, or both. In contrast to the previously discovered pattern that the fixation probability of a neutral mutant decreases while the population becomes younger, we show that a mutant with a constant selective advantage may have a maximum or a minimum of the fixation probability in populations with an intermediate fraction of young individuals. This highlights the importance of life history and demographic structure in studying evolutionary dynamics. We also illustrate the fundamental differences between selection on reproduction and selection on survival when age structure is present. In addition, we evaluate the relative importance of size and structure of the population in determining the fixation probability of the mutant. Our work lays the foundation for also studying density- and frequency-dependent effects in populations when demographic structures cannot be neglected.

  7. Unusual larval habitats and life history of chironomid (Diptera) genera

    USGS Publications Warehouse

    Hudson, Patrick L.

    1987-01-01

    Ninety-three genera, representing all subfamilies of Chironomidae, are organized into 9 categories of unusual habitats or life history including hygropetric, riparian (bank, floodplain, upland), hyporheic, symbiotic, and intertidal; others live in water held in plants or mine into unusual substrates. In riparian zones precise location of optimum habitat is difficult to determine as is definition of habitat within the continuum from shoreline to upland areas. The ecological importance of the riparian group appears to lie in its processing of coarse particulate matter along the floodplain of streams and rivers. All riparian genera are zoogeographically useful and can be used in reconstructing evolutionary dispersal pathways because they are adapted to unique habits that have remained largely undisturbed by human activities.

  8. Disturbance, life history, and optimal management for biodiversity

    USGS Publications Warehouse

    Guo, Q.

    2003-01-01

    Both frequency and intensity of disturbances in many ecosystems have been greatly enhanced by increasing human activities. As a consequence, the short-lived plant species including many exotics might have been dramatically increased in term of both richness and abundance on our planet while many long-lived species might have been lost. Such conclusions can be drawn from broadly observed successional cycles in both theoretical and empirical studies. This article discusses two major issues that have been largely overlooked in current ecosystem management policies and conservation efforts, i.e., life history constraints and future global warming trends. It also addresses the importance of these two factors in balancing disturbance frequency and intensity for optimal biodiversity maintenance and ecosystem management.

  9. Insect life history and the evolution of bacterial mutualism.

    PubMed

    Henry, Lee M; Maiden, Martin C J; Ferrari, Julia; Godfray, H Charles J

    2015-06-01

    Bacterial symbiosis has played a fundamental role in the evolution of eukaryotes. However, we still know little about how cooperative relationships with bacteria originate, and why they form in some host species but not others. Facultative symbionts that are beneficial, but not essential, provide unique insights into these processes. We use data from over a hundred aphid species to test if host life history is associated with the presence of facultative symbionts. We find that aphid species that have mutualistic associations with ants that protect them from natural enemies are less likely to carry symbionts that provide similar benefits. We also find one symbiont species occurs more frequently in unrelated aphid species that specialise on certain plant genera. In addition, aphid species that attack multiple plants often carry different symbiont complements. Our findings provide evidence of the ecological conditions that facilitate stable, mutually beneficial relationships between microbes and eukaryotic hosts.

  10. Life history strategy and the HEXACO personality dimensions.

    PubMed

    Manson, Joseph H

    2015-01-16

    Although several studies have linked Life History Strategy (LHS) variation with variation in the Five Factor Model personality dimensions, no published research has explored the relationship of LHS to the HEXACO personality dimensions. The theoretically expected relationship of the HEXACO Emotionality factor to LHS is unclear. The results of two studies (N = 641) demonstrated that LHS indicators form part of a factor along with HEXACO Extraversion, Agreeableness, Conscientiousness, and (marginally) Honesty-Humility. People higher on these dimensions pursue a slower LHS. Neither Openness nor Emotionality was associated with this factor. Holding LHS constant, social involvement with kin was consistently predicted by higher Emotionality and was not consistently predicted by any other HEXACO factor. These results support a view of Emotionality as part of an LHS-independent personality dimension that influences the provision and receipt of kin altruism.

  11. Encephalization quotients and life-history traits in the Sirenia

    USGS Publications Warehouse

    O'Shea, T.J.; Reep, R.L.

    1990-01-01

    Relative brain size in the Sirenia is unusually small. Encephalization quotients are 0.27 for Florida manatees (Trichechus manatus) and 0.38 for dugongs (Dugong dugon). Estimates for Steller's sea cow (Hydrodamalis gigas) range from 0.12 to 0.19. These values are among the lowest known for Recent mammals, and seemingly have changed little since the Eocene. A body plan specialized for the aquatic environment does not account for low encephalization quotients; values are substantially less than predicted based on cetacean or pinniped allometry. Life-history, ecological, and behavioral traits of the Sirenia are typical of relatively large-brained species. Low quality food and a low metabolic rate, however, are characteristic of the Sirenia and other small-brained mammals. Acting through prolonged postnatal growth, selection also likely favored large body size in the Sirenia without a correlated increase in brain size.

  12. How Life History Can Sway the Fixation Probability of Mutants

    PubMed Central

    Li, Xiang-Yi; Kurokawa, Shun; Giaimo, Stefano; Traulsen, Arne

    2016-01-01

    In this work, we study the effects of demographic structure on evolutionary dynamics when selection acts on reproduction, survival, or both. In contrast to the previously discovered pattern that the fixation probability of a neutral mutant decreases while the population becomes younger, we show that a mutant with a constant selective advantage may have a maximum or a minimum of the fixation probability in populations with an intermediate fraction of young individuals. This highlights the importance of life history and demographic structure in studying evolutionary dynamics. We also illustrate the fundamental differences between selection on reproduction and selection on survival when age structure is present. In addition, we evaluate the relative importance of size and structure of the population in determining the fixation probability of the mutant. Our work lays the foundation for also studying density- and frequency-dependent effects in populations when demographic structures cannot be neglected. PMID:27129737

  13. The evolution of life history trade-offs in viruses.

    PubMed

    Goldhill, Daniel H; Turner, Paul E

    2014-10-01

    Viruses can suffer 'life-history' trade-offs that prevent simultaneous improvement in fitness traits, such as improved intrahost reproduction at the expense of reduced extrahost survival. Here we examine reproduction-survival trade-offs and other trait compromises, highlighting that experimental evolution can reveal trade-offs and their associated mechanisms. Whereas 'curse of the pharaoh' (high virulence with extreme stability) may generally apply for viruses of eukaryotes, we suggest phages are instead likely to suffer virulence/stability trade-offs. We examine how survival/reproduction trade-offs in viruses are affected by environmental stressors, proteins governing viral host range, and organization of the virus genome. Future studies incorporating comparative biology, experimental evolution, and structural biology, could thoroughly determine how viral trade-offs evolve, and whether they transiently or permanently constrain virus adaptation. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Life history and ecology of Cambarus halli (Hobbs)

    USGS Publications Warehouse

    Dennard, S.; Peterson, J.T.; Hawthorne, E.S.

    2009-01-01

    The life history of Cambarus halli, a crayfish endemic to the Tallapoosa River Basin, GA, was studied at four sites within the Tallapoosa River. Two sites had allopatric populations of C. halli, and two sites had populations of C. halli sympatric with C. englishi. Three age classes existed across sites. For Cambarus halli, total number of pleopodal eggs was positively related to carapace length, but egg size was only weakly positively related to carapace length. Cambarus halli were smaller across age classes at sympatric sites, but had greater growth rates than at allopatric sites. Cambarus halli density estimates were lower at sympatric sites, while proportions of reproductively active age-1 and age-2 individuals were higher at allopatric sites (63% vs. 33%).

  15. Life-history tradeoffs and reproductive cycles in Spotted Owls

    USGS Publications Warehouse

    Stoelting, Ricka E.; Gutierrez, R.J.; Kendall, William; Peery, M. Zachariah

    2015-01-01

    The study of tradeoffs among life-history traits has long been key to understanding the evolution of life-history strategies. However, more recently, evolutionary ecologists have realized that reproductive costs have the potential to influence population dynamics. Here, we tested for costs of reproduction in the California Spotted Owl (Strix occidentalis occidentalis), and assessed whether costs of reproduction in year t − 1 on reproduction in year t could be responsible for regionally synchronized biennial cycles in reproductive output. Logistic regression analysis and multistate mark–recapture models with state uncertainty revealed that breeding reduced the likelihood of reproducing in the subsequent year by 16% to 38%, but had no influence on subsequent survival. We also found that costs of reproduction in year t − 1 were correlated with climatic conditions in year t, with evidence of higher costs during the dry phase of the El Niño–Southern Oscillation. Using a simulation-based population model, we showed that strong reproductive costs had the potential to create biennial cycles in population-level reproductive output; however, estimated costs of reproduction appeared to be too small to explain patterns observed in Spotted Owls. In the absence of strong reproductive costs, we hypothesize that observed natural cycles in the reproductive output of Spotted Owls are related to as-yet-unmeasured, regionally concordant fluctuations in environmental conditions or prey resources. Despite theoretical evidence for demographic effects, our analyses illustrate that linking tradeoffs to actual changes in population processes will be challenging because of the potential confounding effects of individual and environmental variation.

  16. Relative tooth size at birth in primates: Life history correlates.

    PubMed

    Smith, Timothy D; Muchlinski, Magdalena N; Bucher, Wade R; Vinyard, Christopher J; Bonar, Christopher J; Evans, Sian; Williams, Lawrence E; DeLeon, Valerie B

    2017-08-19

    Dental eruption schedules have been closely linked to life history variables. Here we examine a sample of 50 perinatal primates (28 species) to determine whether life history traits correlate with relative tooth size at birth. Newborn primates were studied using serial histological sectioning. Volumes of deciduous premolars (dp(2) -dp(4) ), replacement teeth (if any), and permanent molars (M(1-2/3) ) of the upper jaw were measured and residuals from cranial length were calculated with least squares regressions to obtain relative dental volumes (RDVs). Relative dental volumes of deciduous or permanent teeth have an unclear relationship with relative neonatal mass in all primates. Relative palatal length (RPL), used as a proxy for midfacial size, is significantly, positively correlated with larger deciduous and permanent postcanine teeth. However, when strepsirrhines alone are examined, larger RPL is correlated with smaller RDV of permanent teeth. In the full sample, RDVs of deciduous premolars are significantly negatively correlated with relative gestation length (RGL), but have no clear relationship with relative weaning age. RDVs of molars lack a clear relationship with RGL; later weaning is associated with larger molar RDV, although correlations are not significant. When strepsirrhines alone are analyzed, clearer trends are present: longer gestations or later weaning are associated with smaller deciduous and larger permanent postcanine teeth (only gestational length correlations are significant). Our results indicate a broad trend that primates with the shortest RGLs precociously develop deciduous teeth; in strepsirrhines, the opposite trend is seen for permanent molars. Anthropoids delay growth of permanent teeth, while strepsirrhines with short RGLs are growing replacement teeth concurrently. A comparison of neonatal volumes with existing information on extent of cusp mineralization indicates that growth of tooth germs and cusp mineralization may be selected

  17. Reproductive life history traits of female orangutans (Pongo spp.).

    PubMed

    Shumaker, Robert W; Wich, Serge A; Perkins, Lori

    2008-01-01

    Data from wild populations demonstrate that orangutans have the slowest life history of all the great apes. In this chapter, we provide an overview of reproduction and life history traits of female orangutans in the wild and captivity. This comparison of wild and captive data illustrates the variability that exists for orangutans. Wild orangutan females first reproduce at a mean age of 15.4 years, with an age range of 13-18 years, and they have a mean interbirth interval of 9.3 years. Wild male orangutans are conservatively estimated to live at least 58 years, and 53 years for females [1], and to date, there is no evidence to suggest that wild orangutans experience reproductive senescence. We use captive data from 2,566 individuals to show that in captivity orangutan females regularly begin reproducing at the age of 7 and have interbirth intervals that can be shorter than 1 year. We provide additional data that describe the onset and normalization of menses in a young adolescent orangutan as well as the reproductive cycles of three adult females of different ages. Although captive females routinely cycle and reproduce throughout much of their lifespan, age at last reproduction in captivity is 41, which is well before maximum female lifespan. To date, longevity in the wild and in captivity appears equivalent [2]. The reasons for the presence of a postreproductive lifespan in captivity as opposed to its absence in wild populations may be related to management issues. The above results indicate a need for more detailed comparisons between wild and captive orangutans using similar methodologies.

  18. Nests, tree holes, and the evolution of primate life histories.

    PubMed

    Kappeler, P M

    1998-01-01

    In contrast to the majority of primates, many prosimians, some New World monkeys, and the great apes rest in tree holes or self-constructed nests during their inactive periods. The goal of this comparative study was to examine possible functions of this interspecific variation. Information on resting behavior, maternal behavior, and basic life-history traits was gleaned from the literature and mapped onto a phylogenetic tree of primates for various comparative tests. Parsimony-based reconstructions revealed that only the use of nests or tree holes as shelters for young infants can be unequivocally reconstructed for various higher taxa, suggesting that it is functionally different from the use of shelters by adults (who may be accompanied by infants). Further reconstructions revealed that the ancestral primate was most likely nocturnal and solitary and produced a single infant that was initially left in a shelter and later carried orally to a parking place in the vegetation--a combination of traits exhibited by many living galagos. Evolutionary losses of the use of nests were concentrated among diurnal and nonsolitary taxa and weakly associated with evolutionary increases in body size. Thus, protective functions of nests or tree holes used by prosimians are either secondary or there are alternative ways of obtaining protection. Because the evolution of larger litters was significantly associated with the presence of shelters, the presence of relatively altricial young among prosimians best explains the use of nests and tree holes, which are in most but not all cases also used by adults. These shelters therefore play an integral part in the life-history strategies of primitive primates and their ancestors and evolved secondarily among anthropoids for other purposes.

  19. Life history strategy influences parasite responses to habitat fragmentation.

    PubMed

    Froeschke, Götz; van der Mescht, Luther; McGeoch, Melodie; Matthee, Sonja

    2013-12-01

    Anthropogenic habitat use is a major threat to biodiversity and is known to increase the abundance of generalist host species such as rodents, which are regarded as potential disease carriers. Parasites have an intimate relationship with their host and the surrounding environment and it is expected that habitat fragmentation will affect parasite infestation levels. We investigated the effect of habitat fragmentation on the ecto- and endoparasitic burdens of a broad niche small mammal, Rhabdomys pumilio, in the Western Cape Province, South Africa. Our aim was to look at the effects of fragmentation on different parasite species with diverse life history characteristics and to determine whether general patterns can be found. Sampling took place within pristine lowland (Fynbos/Renosterveld) areas and at fragmented sites surrounded and isolated by agricultural activities. All arthropod ectoparasites and available gastrointestinal endoparasites were identified. We used conditional autoregressive models to investigate the effects of habitat fragmentation on parasite species richness and abundance of all recovered parasites. Host density and body size were larger in the fragments. Combined ecto- as well as combined endoparasite taxa showed higher parasite species richness in fragmented sites. Parasite abundance was generally higher in the case of R. pumilio individuals in fragmented habitats but it appears that parasites that are more permanently associated with the host's body and those that are host-specific show the opposite trend. Parasite life history is an important factor that needs to be considered when predicting the effects of habitat fragmentation on parasite and pathogen transmission. Copyright © 2013 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved.

  20. [An ethical decision-making tool. Training for decision-making in crisis or end-of-life situations].

    PubMed

    Gomas, J M

    We developed a patient-centered decision making tool to help healthcare teams make ethical decisions in crisis or end-of-life situations. This tool is the fruit of 15 years of healthcare experience and discussions on ethical issues with patients suffering from cancer, severe handicaps or terminal disease. It has been enriched by experience acquired since the publication of earlier work in the nineties. A three-step decision-making process is proposed providing a methodic aid for management decisions which remain unique for each individual patient.

  1. Computer-assisted diagnostic decision support: history, challenges, and possible paths forward.

    PubMed

    Miller, Randolph A

    2009-09-01

    This paper presents a brief history of computer-assisted diagnosis, including challenges and future directions. Some ideas presented in this article on computer-assisted diagnostic decision support systems (CDDSS) derive from prior work by the author and his colleagues (see list in Acknowledgments) on the INTERNIST-1 and QMR projects. References indicate the original sources of many of these ideas.

  2. Computer-Assisted Diagnostic Decision Support: History, Challenges, and Possible Paths Forward

    ERIC Educational Resources Information Center

    Miller, Randolph A.

    2009-01-01

    This paper presents a brief history of computer-assisted diagnosis, including challenges and future directions. Some ideas presented in this article on computer-assisted diagnostic decision support systems (CDDSS) derive from prior work by the author and his colleagues (see list in Acknowledgments) on the INTERNIST-1 and QMR projects. References…

  3. Computer-Assisted Diagnostic Decision Support: History, Challenges, and Possible Paths Forward

    ERIC Educational Resources Information Center

    Miller, Randolph A.

    2009-01-01

    This paper presents a brief history of computer-assisted diagnosis, including challenges and future directions. Some ideas presented in this article on computer-assisted diagnostic decision support systems (CDDSS) derive from prior work by the author and his colleagues (see list in Acknowledgments) on the INTERNIST-1 and QMR projects. References…

  4. Lifetime learning as a factor in life history education.

    PubMed

    Bullinaria, John A

    2009-01-01

    An artificial life approach is taken to explore the effect that lifetime learning can have on the evolution of certain life history traits, in particular the periods of protection that parents offer young, and the age at first reproduction of those young. The study begins by simulating the evolution of simple artificial neural network systems that must learn quickly to perform well on simple classification tasks, and determining if and when extended periods of parental protection emerge. It is concluded that longer periods of parental protection of children do offer clear learning advantages and better adult performance, but only if procreation is not allowed during the protection period. In this case, a compromise protection period evolves that balances the improved learning performance against reduced procreation period. The crucial properties of the neural learning processes are then abstracted out to explore the possibility of studying the effect of learning more generally and with better computational efficiency. Throughout, the implications of these stimulations for more realistic scenarios are discussed.

  5. Offspring Provisioning Explains Clone-Specific Maternal Age Effects on Life History and Life Span in the Water Flea, Daphnia pulex.

    PubMed

    Plaistow, Stewart J; Shirley, Christopher; Collin, Helene; Cornell, Stephen J; Harney, Ewan D

    2015-09-01

    Genetic inheritance underpins evolutionary theories of aging, but the role that nongenetic inheritance plays is unclear. Parental age reduces the life span of offspring in a diverse array of taxa but has not been explained from an evolutionary perspective. We quantified the effect that maternal age had on the growth and maturation decisions, life history, rates of senescence, and life span of offspring from three Daphnia pulex clones collected from different populations. We then used those data to test general hypotheses proposed to explain maternal age effects on offspring life span. Three generations of breeding from young or old mothers produced dramatic differences in the life histories of fourth-generation offspring, including significant reductions in life span. The magnitude of the effect differed between clones, which suggests that genetic and nongenetic factors ultimately underpin trait inheritance and shape patterns of aging. Older parents did not transmit a senescent state to their offspring. Instead, offspring from older ancestors had increased early-life reproductive effort, which resulted in an earlier onset of reproductive senescence, and an increased rate of actuarial senescence, which shortened their life span. Our results provide a clear example of the need to consider multiple inheritance mechanisms when studying trait evolution.

  6. Historical and Contemporary Issues in End-of-Life Decisions: Implications for Social Work

    ERIC Educational Resources Information Center

    Mackelprang, Romel W.; Mackelprang, Romel D.

    2005-01-01

    End-of-life circumstances have changed dramatically in recent years. In the past century life expectancy has increased by 62 percent and people are living longer with chronic illness. This article discusses evolving health practices and policies in end-of-life decisions. Treatments to prolong life and provide comfort, and interventions that hasten…

  7. Historical and Contemporary Issues in End-of-Life Decisions: Implications for Social Work

    ERIC Educational Resources Information Center

    Mackelprang, Romel W.; Mackelprang, Romel D.

    2005-01-01

    End-of-life circumstances have changed dramatically in recent years. In the past century life expectancy has increased by 62 percent and people are living longer with chronic illness. This article discusses evolving health practices and policies in end-of-life decisions. Treatments to prolong life and provide comfort, and interventions that hasten…

  8. End-of-life decisions: an important theme in the care for people with intellectual disabilities.

    PubMed

    Wagemans, A; van Schrojenstein Lantman-de-Valk, H; Tuffrey-Wijne, I; Widdershoven, G; Curfs, L

    2010-06-01

    While end-of-life decisions in the general population have received attention in several countries, not much is known about this in people with intellectual disabilities (IDs). Therefore, the prevalence and nature of end-of-life decisions were investigated in a Dutch centre providing residential care for 335 people with IDs. A retrospective study of medical files of people who died between January 2002 and July 2007. One or more end-of-life decisions were taken in 27 out of 47 cases. A non-treatment decision was taken for seven residents, possibly shortening life expectancy in some cases. The family was involved in decision making in half of the 27 cases. No information was found about the process of end-of-life decision making. There was no evidence in the notes that any of the people with IDs was asked for his or her own opinion in taking an end-of-life decision. This study demonstrates that medical end-of-life decisions played a part in significant numbers of people with IDs who have died within this centre, but further studies are needed to establish decision-making processes.

  9. Parent decision making for life support for extremely premature infants: from the prenatal through end-of-life period.

    PubMed

    Moro, Teresa T; Kavanaugh, Karen; Savage, Teresa A; Reyes, Maria R; Kimura, Robert E; Bhat, Rama

    2011-01-01

    Most deaths of extremely premature infants occur in the perinatal period. Yet, little is known about how parents make life support decisions in such a short period of time. In the paper, how parents make life support decisions for extremely premature infants from the prenatal period through death from the perspectives of parents, nurses, and physicians is described. Five cases, comprised of five mothers, four neonatologists, three nurses, and one neonatal nurse practitioner, are drawn from a larger collective case study. Prenatal, postnatal and end-of-life interviews were conducted, and medical record data were obtained. In an analysis by two research team members, mothers were found to exhibit these characteristics: desire for and actual involvement in life support decisions, weighing pain, suffering and hope in decision making, and wanting everything done for their infants. All mothers received decision making help and support from partners and family, but relationships with providers were also important. Finally, external resources impacted parental decision making in several of the cases. By understanding what factors contribute to parents' decision making, providers may be better equipped to prepare and assist parents when making life support decisions for their extremely premature infants.

  10. Resource allocation as a driver of senescence: life history tradeoffs produce age patterns of mortality.

    PubMed

    Davison, Raziel; Boggs, Carol L; Baudisch, Annette

    2014-11-07

    We investigate the effects of optimal time and resource allocation on age patterns of fertility and mortality for a model organism with (1) fixed maximum lifespan, (2) distinct juvenile and adult diets, and (3) reliance on nonrenewable resources for reproduction. We ask when it is optimal to tolerate starvation vs. conserve resources and then examine the effects of these decisions on adult mortality rates. We find that (1) age-related changes in tradeoffs partition the life cycle into as many as four discrete phases with different optimal behavior and mortality patterns, and (2) given a cost of reproduction, terminal investment can produce a signal of actuarial senescence. Also, given limitations imposed by non-replenishable resources, individuals beginning adult life with more replenishable resources do not necessarily live longer, since they can engage in capital breeding and need not defer reproduction to forage; low reproductive overheads and low costs of starvation also encourage capital breeding and may lead to earlier terminal investment and earlier senescence. We conclude that, even for species with qualitatively similar life histories, differences in physiological, behavioral and environmental tradeoffs or constraints may strongly influence optimal allocation schedules and produce variation in mortality patterns and life expectancy. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. End-of-Life Decisions: An Important Theme in the Care for People with Intellectual Disabilities

    ERIC Educational Resources Information Center

    Wagemans, A.; van Schrojenstein Lantman-de-Valk, H.; Tuffrey-Wijne, I.; Widdershoven, G.; Curfs, L.

    2010-01-01

    Background: While end-of-life decisions in the general population have received attention in several countries, not much is known about this in people with intellectual disabilities (IDs). Therefore, the prevalence and nature of end-of-life decisions were investigated in a Dutch centre providing residential care for 335 people with IDs. Method: A…

  12. Bedside nurse involvement in end-of-life decision making: a brief review of the literature.

    PubMed

    Erickson, Jodi

    2013-01-01

    Bedside nurses in the critical care setting deal with death on a regular basis. Historically, end-of-life decision making has been addressed by physicians with the family and patient, yet nurses may be a better resource for families during the decision-making process. The purpose of this article was to provide a brief review of literature surrounding end-of-life decision making. As patient advocates, nurses should be more actively involved with facilitating the end-of-life decision-making process for critically ill patients and their families.

  13. From metamorphosis to maturity in complex life cycles: equal performance of different juvenile life history pathways.

    PubMed

    Schmidt, Benedikt R; Hödl, Walter; Schaub, Michael

    2012-03-01

    Performance in one stage of a complex life cycle may affect performance in the subsequent stage. Animals that start a new stage at a smaller size than conspecifics may either always remain smaller or they may be able to "catch up" through plasticity, usually elevated growth rates. We study how size at and date of metamorphosis affected subsequent performance in the terrestrial juvenile stage and lifetime fitness of spadefoot toads (Pelobates fuscus). We analyzed capture-recapture data of > 3000 individuals sampled during nine years with mark-recapture models to estimate first-year juvenile survival probabilities and age-specific first-time breeding probabilities of toads, followed by model selection to assess whether these probabilities were correlated with size at and date of metamorphosis. Males attained maturity after two years, whereas females reached maturity 2-4 years after metamorphosis. Age at maturity was weakly correlated with metamorphic traits. In both sexes, first-year juvenile survival depended positively on date of metamorphosis and, in males, also negatively on size at metamorphosis. In males, toads that metamorphosed early at a small size had the highest probability to reach maturity. However, because very few toadlets metamorphosed early, the vast majority of male metamorphs had a very similar probability to reach maturity. A matrix projection model constructed for females showed that different juvenile life history pathways resulted in similar lifetime fitness. We found that the effects of date of and size at metamorphosis on different juvenile traits cancelled each other out such that toads that were small or large at metamorphosis had equal performance. Because the costs and benefits of juvenile life history pathways may also depend on population fluctuations, ample phenotypic variation in life history traits may be maintained.

  14. Implications of ecological energetics and biophysical and developmental constraints for life history variation in dinosaurs

    SciTech Connect

    Dunham, A.E.; Overall, K.L.; Forster, C.A.; Porter, W.P.

    1988-01-01

    There has been much recent speculation concerning the nature of life history variation in dinosaurs (Case, 1978; Bakker, 1986; Horner, 1982, 1984a). The purpose of this paper is to review the data on dinosaur life histories and to examine the nature and magnitude of the demographic and physiological factors that must have constrained life history variation in this group. 145 refs., 8 figs., 3 tabs.

  15. The Primate Life History Database: A unique shared ecological data resource

    PubMed Central

    Strier, Karen B.; Altmann, Jeanne; Brockman, Diane K.; Bronikowski, Anne M.; Cords, Marina; Fedigan, Linda M.; Lapp, Hilmar; Liu, Xianhua; Morris, William F.; Pusey, Anne E.; Stoinski, Tara S.; Alberts, Susan C.

    2011-01-01

    Summary The importance of data archiving, data sharing, and public access to data has received considerable attention. Awareness is growing among scientists that collaborative databases can facilitate these activities.We provide a detailed description of the collaborative life history database developed by our Working Group at the National Evolutionary Synthesis Center (NESCent) to address questions about life history patterns and the evolution of mortality and demographic variability in wild primates.Examples from each of the seven primate species included in our database illustrate the range of data incorporated and the challenges, decision-making processes, and criteria applied to standardize data across diverse field studies. In addition to the descriptive and structural metadata associated with our database, we also describe the process metadata (how the database was designed and delivered) and the technical specifications of the database.Our database provides a useful model for other researchers interested in developing similar types of databases for other organisms, while our process metadata may be helpful to other groups of researchers interested in developing databases for other types of collaborative analyses. PMID:21698066

  16. Counterfactuals and history: Contingency and convergence in histories of science and life.

    PubMed

    Hesketh, Ian

    2016-08-01

    This article examines a series of recent histories of science that have attempted to consider how science may have developed in slightly altered historical realities. These works have, moreover, been influenced by debates in evolutionary science about the opposing forces of contingency and convergence in regard to Stephen Jay Gould's notion of "replaying life's tape." The article argues that while the historians under analysis seem to embrace contingency in order to present their counterfactual narratives, for the sake of historical plausibility they are forced to accept a fairly weak role for contingency in shaping the development of science. It is therefore argued that Simon Conway Morris's theory of evolutionary convergence comes closer to describing the restrained counterfactual worlds imagined by these historians of science than does contingency.

  17. The Dark Triad Traits from a Life History Perspective in Six Countries.

    PubMed

    Jonason, Peter K; Foster, Joshua D; Egorova, Marina S; Parshikova, Oksana; Csathó, Árpád; Oshio, Atsushi; Gouveia, Valdiney V

    2017-01-01

    Work on the Dark Triad traits has benefited from the use of a life history framework but it has been limited to primarily Western samples and indirect assessments of life history strategies. Here, we examine how the Dark Triad traits (i.e., psychopathy, Machiavellianism, and narcissism) relate to two measures of individual differences in life history strategies. In Study 1 (N = 937), we replicated prior observed links between life history strategies, as measured by the Mini-K, and the Dark Triad traits using samples recruited from three countries. In Study 2 (N = 1032), we measured life history strategies using the Consideration of Future Consequences Scale and correlated it with the Dark Triad traits in samples recruited from three additional countries. While there was some variability across participants' sex and country, the results were generally consistent in that psychopathy and (to a lesser extent) Machiavellianism were related to faster life history strategies and narcissism was related to slower life history strategies. These results add cross-cultural data and the use of two measures of life history speed to understand the Dark Triad traits from a life history perspective.

  18. Functional Linkages for the Pace of Life, Life-history, and Environment in Birds

    PubMed Central

    Williams, Joseph B.; Miller, Richard A.; Harper, James M.; Wiersma, Popko

    2010-01-01

    For vertebrates, body mass underlies much of the variation in metabolism, but among animals of the same body mass, metabolism varies six-fold. Understanding how natural selection can influence variation in metabolism remains a central focus of Physiological Ecologists. Life-history theory postulates that many physiological traits, such as metabolism, may be understood in terms of key maturational and reproductive characteristics over an organism’s life-span. Although it is widely acknowledged that physiological processes serve as a foundation for life-history trade-offs, the physiological mechanisms that underlie the diversification of life-histories remain elusive. Data show that tropical birds have a reduced basal metabolism (BMR), field metabolic rate, and peak metabolic rate compared with temperate counterparts, results consistent with the idea that a low mortality, and therefore increased longevity, and low productivity is associated with low mass-specific metabolic rate. Mass-adjusted BMR of tropical and temperate birds was associated with survival rate, in accordance with the view that animals with a slow pace of life tend to have increased life spans. To understand the mechanisms responsible for a reduced rate of metabolism in tropical birds compared with temperate species, we summarized an unpublished study, based on data from the literature, on organ masses for both groups. Tropical birds had smaller hearts, kidneys, livers, and pectoral muscles than did temperate species of the same body size, but they had a relatively larger skeletal mass. Direct measurements of organ masses for tropical and temperate birds showed that the heart, kidneys, and lungs were significantly smaller in tropical birds, although sample sizes were small. Also from an ongoing study, we summarized results to date on connections between whole-organism metabolism in tropical and temperate birds and attributes of their dermal fibroblasts grown in cell culture. Cells derived from

  19. Life in varying environments: experimental evidence for delayed effects of juvenile environment on adult life history.

    PubMed

    Helle, Heikki; Koskela, Esa; Mappes, Tapio

    2012-05-01

    1. The effects of environment experienced during early development on phenotype as an adult has started to gain vast amounts of interest in various taxa. Some evidence on long-term effects of juvenile environment is available, but replicated experimental studies in wild animals are still lacking. 2. Here we report the first replicated experiment in wild mammals which examines the long-term effects of juvenile and adult environments on individual fitness (reproduction, survival and health). The early development of bank vole (Myodes glareolus) individuals took place in either food-supplemented or un-supplemented outdoor enclosures. After the summer, adult individuals were reciprocally changed to either a similar or opposite resource environment to overwinter. 3. Adult environment had an overriding effect on reproductive success of females so that females overwintering in food-supplemented enclosures had a higher probability of breeding and advanced the initiation of breeding. However, the characteristics of their litters were determined by juvenile environment: females initially grown in food-supplemented conditions subsequently produced larger litters with bigger pups and a male-biased sex ratio. 4. In males, individuals growing in un-supplemented conditions had the highest survival irrespective of adult environment during winter, whereas in females, neither the juvenile nor adult environments affected their survival significantly. The physiological condition of voles in spring, as determined by haematological parameters, was also differentially affected by juvenile (plasma proteins and male testosterone) and adult (haematocrit) environments. 5. Our results suggest that (i) life-history trajectories of voles are not strictly specialized to a certain environment and (ii) the plastic life-history responses to present conditions can actually be caused by delayed effects of the juvenile environment. More generally, the results are important for understanding

  20. A Course on Humanistic Creativity in Later Life: Literature Review, Case Histories, and Recommendations.

    ERIC Educational Resources Information Center

    Nuessel, Frank; Van Stewart, Arthur; Cedeno, Aristofanes

    2001-01-01

    Presents case histories of late-life creativity in literature (May Sarton), painting (Marcel Duchamp), music (Leos Janacek), dance (Martha Graham), and theatre (Jessica Tandy). Offers suggestions for a course on humanistic creativity in later life. (Contains 74 references.) (SK)

  1. A Course on Humanistic Creativity in Later Life: Literature Review, Case Histories, and Recommendations.

    ERIC Educational Resources Information Center

    Nuessel, Frank; Van Stewart, Arthur; Cedeno, Aristofanes

    2001-01-01

    Presents case histories of late-life creativity in literature (May Sarton), painting (Marcel Duchamp), music (Leos Janacek), dance (Martha Graham), and theatre (Jessica Tandy). Offers suggestions for a course on humanistic creativity in later life. (Contains 74 references.) (SK)

  2. Life history, diversity and distribution: A study of Japanese pteridophytes

    USGS Publications Warehouse

    Guo, Q.; Kato, Masako; Ricklefs, R.E.

    2003-01-01

    Many studies address the relationships between diversity or distribution and attributes of the physical environment. However, how these relationships are connected to variation in life history is poorly understood. This is particularly true in the case of pteridophytes. Japanese ferns and their allies comprise one of the best-known pteridophyte floras in the world. We analyzed ca 600 species of Japanese pteridophytes for which there is detailed information on distribution, reproduction, and chromosome number. Species richness was greatest in groups with a single reproductive mode (sexual, followed by apogamous), but distribution was greatest in species groups with multiple reproductive modes: sexual plus either sterile (irregular in meiosis) or apogamous. Geographical ranges varied greatly among species with small chromosome numbers but were uniformly small among species having high chromosome numbers. Seasonally green (mostly summer green) species had significantly larger distribution ranges than evergreen species. Endemic species had higher proportions of apogamy and sterility than non-endemic species. Seasonally green species had significantly larger distributional ranges, and a smaller proportion of species with apogamous reproduction, than evergreen species. There was no clear relationship between distribution and spore size, either among endemic species, non-endemic species, or all species combined. There was no relationship between spore size and chromosome number when all species were combined. However, positive relationships were detected within three of the nine largest genera, suggesting potential phylogenetic effects. We concluded that habitat availability, rather than dispersability, may be the limiting factor for the distribution of pteridophytes in Japan.

  3. Juvenility in the context of life history theory.

    PubMed

    Hochberg, Z

    2008-06-01

    Homo sapiens is unique in having four prolonged and pronounced postnatal pre-adult life history stages: infancy, which lasts for 30-36 months and ends with weaning from breast feeding in traditional societies; childhood, which lasts for an additional 2-4 years and concludes in a degree of independence as regards protection and food provision; a juvenile stage of 3-4 years that terminates with readiness for sexual maturation; and adolescence, which lasts for 3-5 years and culminates in fertility. Juvenility implies two transitional periods which are only experienced by humans: a transition from childhood to juvenility and from juvenility to adolescence. Juvenility, "the age of reason and responsibility" and concrete operation, coincides with elementary school age and offers opportunities to prepare for the social complexity of adolescence. Here I define the transition to juvenility by three variables: adrenarche (the onset of adrenal androgen generation), growth pattern (decelerating from a linear childhood growth velocity) and adiposity rebound acceleration of body mass index. The data presented suggest that this period is endowed with programming/predictive adaptive responses of body composition to the environment.

  4. Heritability of Morphology in Brook Trout with Variable Life Histories

    PubMed Central

    Varian, Anna; Nichols, Krista M.

    2010-01-01

    Distinct morphological variation is often associated with variation in life histories within and among populations of both plants and animals. In this study, we examined the heritability of morphology in three hatchery strains of brook trout (Salvelinus fontinalis), which were historically or are currently used for stocking and supplementation of both migratory and resident ecotypes in the upper Great Lakes region. In a common garden experiment, significant variation in body morphology was observed within and across populations sampled at three time periods. The most notable differences among strains were differences in dorso-ventral body depth and the shape of the caudal peduncle, with some differences in the anterior-posterior placement of the dorsal and ventral fins. Variation with and among 70 half-sib families indicates that heritabilities of morphology and body size were significant at most developmental time points both within and across strains. Heritabilities for morphological characters within strains ranged from 0 to 0.95 across time points. Significant within-strain heritabilities for length ranged from 0 to 0.93 across time points and for weight ranged from 0 to 0.88. Significant additive genetic variation exists within and across hatchery brook trout strains for morphology and size, indicating that these traits are capable of responding to natural or artificial selection. PMID:20886080

  5. Life history dictates fluorosis risk in a small mammal community

    SciTech Connect

    Rafferty, D.P.; Faulkner, B.; Lochmiller, R.L.; Qualls, C.W. Jr.; McBee, K.

    1995-12-31

    Dental lesions, due to fluorosis, previously have been reported in wild, male cotton rats (Sigmodon hispidus) on an abandoned oil refinery located at the Oklahoma Refining Company in Cyril, Oklahoma. This study was expanded to include examinations of the fulvous harvest mouse (Reithrodontomys fulvescens), house mouse (Mus musculus), prairie vole (Microtus ochrogaster), plains pocket gopher (Geomys bursarius), least shrew (Cryptotis parva), shorttailed shrew (Blarina brevicauda), and deer mouse (Peromyscus spp.) at this same site. A sample of each species was collected form the contaminated refining site and a reference site with no known contamination. The authors grossly scored dentition of lower and upper incisors, microscopically examined cellular aberrations in ameloblasts and ondontoblasts, and quantified femur fluoride levels. Alterations in the lower and upper incisors were common in prairie voles, whose incisors possessed striations and erosion of the enamel and appeared chalky white. Incisors of animals taken from the reference site were normal. Patterns in occurrence of fluorosis and degree of enamel erosion was examined relative to the life history characteristics of the species.

  6. Life-history evolution when Lestes damselflies invaded vernal ponds.

    PubMed

    De Block, Marjan; McPeek, Mark A; Stoks, Robby

    2008-02-01

    We know little about the macroevolution of life-history traits along environmental gradients, especially with regard to the directionality compared to the ancestral states and the associated costs to other functions. Here we examine how age and size at maturity evolved when Lestes damselflies shifted from their ancestral temporary pond habitat (i.e., ponds that may dry once every decade or so) to extremely ephemeral vernal ponds (ponds that routinely dry completely each year). Larvae of three species were reared from eggs until emergence under different levels of photoperiod and transient starvation stress. Compared to the two temporary-pond Lestes, the phylogenetically derived vernal-pond Lestes dryas developed more rapidly across photoperiod treatments until the final instar, and only expressed plasticity in development time in the final instar under photoperiod levels that simulated a later hatching date. The documented change in development rate can be considered adaptive and underlies the success of the derived species in vernal ponds. Results suggest associated costs of faster development are lower mass at maturity and lower immune function after transient starvation stress. These costs may not only have impeded further evolution of the routine development rate to what is physiologically maximal, but also maintained some degree of plasticity to time constraints when the habitat shift occurred.

  7. Life history of the blackspotted whipray Himantura astra.

    PubMed

    Jacobsen, I P; Bennett, M B

    2011-04-01

    Features of the life history of Himantura astra from north-east Australia were examined including its age and growth, reproduction and diet. Centrum edge and marginal increment ratio analyses were used to validate annual band formations with the Gompertz growth function providing the best fit to male (W(D∞) = 722·7 mm, k = 0·104) and female (W(D∞) = 821·8 mm, k = 0·073) disc width (W(D))-at-age data. At 29 years, the maximum age of females was higher than males (18 years). Sizes at 50% sexual maturity (W(D50)) for males and females were 469·3 and 462·3 mm, respectively. Ages at sexual maturity (A(M50)) were reported at 7·32 (males) and 8·67 (females) years. An index of relative importance (I(RI)) revealed carid shrimps (77·9%), brachyurans (12·1%) and stomatopods (4·9%) as the most important prey groups, with prey diversity increasing with W(D) from 0·92 to 1·63 (Shannon-Weiner index). This study provides significant insights into the biology of H. astra and contributes to the ongoing development of fisheries-based risk assessments for this species. © 2011 The Authors. Journal of Fish Biology © 2011 The Fisheries Society of the British Isles.

  8. Allomaternal care, life history and brain size evolution in mammals.

    PubMed

    Isler, Karin; van Schaik, Carel P

    2012-07-01

    Humans stand out among the apes by having both an extremely large brain and a relatively high reproductive output, which has been proposed to be a consequence of cooperative breeding. Here, we test for general correlates of allomaternal care in a broad sample of 445 mammal species, by examining life history traits, brain size, and different helping behaviors, such as provisioning, carrying, huddling or protecting the offspring and the mother. As predicted from an energetic-cost perspective, a positive correlation between brain size and the amount of help by non-mothers is found among mammalian clades as a whole and within most groups, especially carnivores, with the notable exception of primates. In the latter group, the presence of energy subsidies during breeding instead resulted in increased fertility, up to the extreme of twinning in callitrichids, as well as a more altricial state at birth. In conclusion, humans exhibit a combination of the pattern found in provisioning carnivores, and the enhanced fertility shown by cooperatively breeding primates. Our comparative results provide support for the notion that cooperative breeding allowed early humans to sidestep the generally existing trade-off between brain size and reproductive output, and suggest an alternative explanation to the controversial 'obstetrical dilemma'-argument for the relatively altricial state of human neonates at birth. Copyright © 2012 Elsevier Ltd. All rights reserved.

  9. Ladybird-induced life-history changes in aphids

    PubMed Central

    Dixon, A. F. G.; Agarwala, B. K.

    1999-01-01

    Predator-mediated plasticity in the morphology, life history and behaviour of prey organisms has been widely reported in freshwater ecosystems. Although clearly adaptive, similar responses have only recently been reported for terrestrial organisms. This is surprising as aphids are polyphenic and develop very rapidly compared with their predators and often produce very large colonies, which are attractive to predators. Therefore, one might expect terrestrial organisms like aphids to show a facultative change in their development in response to the presence of predators and other results have confirmed this. The results presented below indicate that the pea aphid responded to the tracks left by ladybird larvae by producing a greater proportion of winged offspring, which avoid the impending increased risk of predation by dispersing. Associated with this was a short-term increase in activity and reduction in fecundity. The black bean and vetch aphids, which are afforded some protection from ladybirds because they are ant attended and/or unpalatable, did not respond in this way to the presence of ladybird larvae.

  10. The Pain Management Life History Calendar: A Pilot Study.

    PubMed

    McDonald, Deborah Dillon; Barri, Caroline

    2015-08-01

    Pain management trajectory data that includes previous pain treatments, timing, changes, and outcomes provide crucial data for patients with chronic pain and their practitioners to use when discussing ways to optimize pain management regimens. The aim of this study was to test the use of the life history calendar method to identify pain treatments, treatment regimens, timing, and outcomes of the pain management trajectory of individuals with chronic pain, and to examine feasibility. A pilot, descriptive, methodological design was used. Settings included community-based sites such as congregate housing. Nineteen community-dwelling older adults with osteoarthritis (OA) pain of at least 1 year's duration participated. Participants were interviewed and asked to chronicle from the beginning of the OA pain to the present all of their pain treatments and treatment effects (pain outcomes and adverse events). Raters independently content analyzed the transcribed interviews to identify pain treatments, treatment groupings (regimens), and treatment effects on pain. Feasibility of patients reporting their pain management trajectories was content analyzed by identifying participant difficulty identifying pain treatments, treatment effects, treatment sequence; and difficulty discriminating between treatments, and between OA pain and other pain sources. Individual pain management trajectories were constructed that depicted chronological order of pain treatment regimens and treatment effects. Participants identified pain treatments, discriminate between treatments and between OA and other conditions, and identified treatment effects. Treatment sequence was identified, but more precise timing was generally not reported. Pain management trajectories could provide a helpful way for practitioners to discuss safe, efficacious pain management options with patients.

  11. Life History of a Unique Asian Plethodontid Salamander, Karsenia koreana.

    PubMed

    Song, Jae-Young; Matsui, Masafumi; Matsuki, Takashi; Nishikawa, Kanto; Koo, Kyo-Soung; Oh, Hong-Shik

    2017-04-01

    Using preserved specimens, we studied the basic life history of the topotypic population of the unique Asian plethodontid salamander, Karsenia koreana. Of 51 individuals examined, 11 males and 13 females were judged as mature from the development of gonads. The ovarian eggs were large (diameter 3.7-4.8 mm) and yellow to orange in color, and the clutch size was about 8-10. These values approximate those of actually spawned eggs recently reported. Skeletochronological analyses revealed the average age of males (5.3 years) to be lower than females (7.3 years). The age at maturity and maximum observed longevity were four and nine years in males and five and 10 years in females, respectively. In the growth curves estimated by a von Bertalanffy growth model, the growth coefficient and asymptotic SVL did not differ between the sexes, although males (40.6 mm) were smaller than females (45.3 mm) in the average snout-vent length. The time and place of courtship behavior, oval development, hatching, and especially, whether the species shows aquatic larval stage or direct development, are important topics to be resolved in future.

  12. Phylogenetic signal in primate behaviour, ecology and life history.

    PubMed

    Kamilar, Jason M; Cooper, Natalie

    2013-05-19

    Examining biological diversity in an explicitly evolutionary context has been the subject of research for several decades, yet relatively recent advances in analytical techniques and the increasing availability of species-level phylogenies, have enabled scientists to ask new questions. One such approach is to quantify phylogenetic signal to determine how trait variation is correlated with the phylogenetic relatedness of species. When phylogenetic signal is high, closely related species exhibit similar traits, and this biological similarity decreases as the evolutionary distance between species increases. Here, we first review the concept of phylogenetic signal and suggest how to measure and interpret phylogenetic signal in species traits. Second, we quantified phylogenetic signal in primates for 31 variables, including body mass, brain size, life-history, sexual selection, social organization, diet, activity budget, ranging patterns and climatic variables. We found that phylogenetic signal varies extensively across and even within trait categories. The highest values are exhibited by brain size and body mass, moderate values are found in the degree of territoriality and canine size dimorphism, while low values are displayed by most of the remaining variables. Our results have important implications for the evolution of behaviour and ecology in primates and other vertebrates.

  13. Recovery from disordered eating: what life histories reveal.

    PubMed

    Redenbach, Joanna; Lawler, Jocalyn

    2003-08-01

    There are few studies seeking to understand the illness from the experiential perspective of a person who has recovered from an eating disorder. The clinical and research literature shows inconsistencies and varying degrees of support for the risk factors associated with eating disordered behaviour. It is important to note, however, that most contemporary research relies upon brief self-report questionnaires, which may be providing a fragmented picture of the behaviour. The focus of the current study is to gain a greater understanding of women's perceptions of developing, living with and recovering from an eating disorder. This study reports interviews with five former eating disorder sufferers who were recruited via an advertisement placed in an Eating Disorders Support Network newsletter. Life histories were gathered from each woman and the paper reports how these women perceive the origins of their illness and what event(s) lead to their recovery. Participants' narratives were analysed to elucidate themes pertaining to the lived experience of illness and recovery. The women talk about a lack of control of their lives and unrealistic family expectations as reasons for the development of their eating disordered behaviour. Recovery was very strongly related to self-determination and self-acceptance. Suggestions concerning new ways of conceptualising recovery from eating disordered behaviour are posited.

  14. Life-history theory, fertility and reproductive success in humans.

    PubMed

    Strassmann, Beverly I; Gillespie, Brenda

    2002-03-22

    According to life-history theory, any organism that maximizes fitness will face a trade-off between female fertility and offspring survivorship. This trade-off has been demonstrated in a variety of species, but explicit tests in humans have found a positive linear relationship between fitness and fertility. The failure to demonstrate a maximum beyond which additional births cease to enhance fitness is potentially at odds with the view that human fertility behaviour is currently adaptive. Here we report, to our knowledge, the first clear evidence for the predicted nonlinear relationship between female fertility and reproductive success in a human population, the Dogon of Mali, West Africa. The predicted maximum reproductive success of 4.1+/-0.3 surviving offspring was attained at a fertility of 10.5 births. Eighty-three per cent of the women achieved a lifetime fertility level (7-13 births) for which the predicted mean reproductive success was within the confidence limits (3.4 to 4.8) for reproductive success at the optimal fertility level. Child mortality, rather than fertility, was the primary determinant of fitness. Since the Dogon people are farmers, our results do not support the assumptions that: (i) contemporary foragers behave more adaptively than agriculturalists, and (ii) that adaptive fertility behaviour ceased with the Neolithic revolution some 9000 years ago. We also present a new method that avoids common biases in measures of reproductive success.

  15. Life-history theory, fertility and reproductive success in humans.

    PubMed Central

    Strassmann, Beverly I; Gillespie, Brenda

    2002-01-01

    According to life-history theory, any organism that maximizes fitness will face a trade-off between female fertility and offspring survivorship. This trade-off has been demonstrated in a variety of species, but explicit tests in humans have found a positive linear relationship between fitness and fertility. The failure to demonstrate a maximum beyond which additional births cease to enhance fitness is potentially at odds with the view that human fertility behaviour is currently adaptive. Here we report, to our knowledge, the first clear evidence for the predicted nonlinear relationship between female fertility and reproductive success in a human population, the Dogon of Mali, West Africa. The predicted maximum reproductive success of 4.1+/-0.3 surviving offspring was attained at a fertility of 10.5 births. Eighty-three per cent of the women achieved a lifetime fertility level (7-13 births) for which the predicted mean reproductive success was within the confidence limits (3.4 to 4.8) for reproductive success at the optimal fertility level. Child mortality, rather than fertility, was the primary determinant of fitness. Since the Dogon people are farmers, our results do not support the assumptions that: (i) contemporary foragers behave more adaptively than agriculturalists, and (ii) that adaptive fertility behaviour ceased with the Neolithic revolution some 9000 years ago. We also present a new method that avoids common biases in measures of reproductive success. PMID:11916470

  16. Life history theory and breast cancer risk: methodological and theoretical challenges: Response to "Is estrogen receptor negative breast cancer risk associated with a fast life history strategy?".

    PubMed

    Aktipis, Athena

    2016-01-01

    In a meta-analysis published by myself and co-authors, we report differences in the life history risk factors for estrogen receptor negative (ER-) and estrogen receptor positive (ER+) breast cancers. Our meta-analysis did not find the association of ER- breast cancer risk with fast life history characteristics that Hidaka and Boddy suggest in their response to our article. There are a number of possible explanations for the differences between their conclusions and the conclusions we drew from our meta-analysis, including limitations of our meta-analysis and methodological challenges in measuring and categorizing estrogen receptor status. These challenges, along with the association of ER+ breast cancer with slow life history characteristics, may make it challenging to find a clear signal of ER- breast cancer with fast life history characteristics, even if that relationship does exist. The contradictory results regarding breast cancer risk and life history characteristics illustrate a more general challenge in evolutionary medicine: often different sub-theories in evolutionary biology make contradictory predictions about disease risk. In this case, life history models predict that breast cancer risk should increase with faster life history characteristics, while the evolutionary mismatch hypothesis predicts that breast cancer risk should increase with delayed reproduction. Whether life history tradeoffs contribute to ER- breast cancer is still an open question, but current models and several lines of evidence suggest that it is a possibility. © The Author(s) 2016. Published by Oxford University Press on behalf of the Foundation for Evolution, Medicine, and Public Health.

  17. End-of-life decisions in Malaysia: Adequacies of ethical codes and developing legal standards.

    PubMed

    Kassim, Puteri Nemie Jahn; Alias, Fadhlina

    2015-06-01

    End-of-life decision-making is an area of medical practice in which ethical dilemmas and legal interventions have become increasingly prevalent. Decisions are no longer confined to clinical assessments; rather, they involve wider considerations such as a patient's religious and cultural beliefs, financial constraints, and the wishes and needs of family members. These decisions affect everyone concerned, including members of the community as a whole. Therefore it is imperative that clear ethical codes and legal standards are developed to help guide the medical profession on the best possible course of action for patients. This article considers the relevant ethical, codes and legal provisions in Malaysia governing certain aspects of end-of-life decision-making. It highlights the lack of judicial decisions in this area as well as the limitations with the Malaysian regulatory system. The article recommends the development of comprehensive ethical codes and legal standards to guide end-of-life decision-making in Malaysia.

  18. The Tsimane Health and Life History Project: Integrating anthropology and biomedicine

    PubMed Central

    Stieglitz, Jonathan; Trumble, Benjamin; Blackwell, Aaron D.; Beheim, Bret; Davis, Helen; Hooper, Paul; Kaplan, Hillard

    2017-01-01

    Abstract The Tsimane Health and Life History Project, an integrated bio‐behavioral study of the human life course, is designed to test competing hypotheses of human life‐history evolution. One aim is to understand the bidirectional connections between life history and social behavior in a high‐fertility, kin‐based context lacking amenities of modern urban life (e.g. sanitation, banks, electricity). Another aim is to understand how a high pathogen burden influences health and well‐being during development and adulthood. A third aim addresses how modernization shapes human life histories and sociality. Here we outline the project's goals, history, and main findings since its inception in 2002. We reflect on the implications of current findings and highlight the need for more coordinated ethnographic and biomedical study of contemporary nonindustrial populations to address broad questions that can situate evolutionary anthropology in a key position within the social and life sciences. PMID:28429567

  19. A history of evidence in medical decisions: from the diagnostic sign to Bayesian inference.

    PubMed

    Mazur, Dennis J

    2012-01-01

    Bayesian inference in medical decision making is a concept that has a long history with 3 essential developments: 1) the recognition of the need for data (demonstrable scientific evidence), 2) the development of probability, and 3) the development of inverse probability. Beginning with the demonstrative evidence of the physician's sign, continuing through the development of probability theory based on considerations of games of chance, and ending with the work of Jakob Bernoulli, Laplace, and others, we will examine how Bayesian inference developed.

  20. The Effect of Providing Life Support on Nurses' Decision Making Regarding Life Support for Themselves and Family Members in Japan.

    PubMed

    Shaku, Fumio; Tsutsumi, Madoka

    2016-12-01

    Decision making in terminal illness has recently received increased attention. In Japan, patients and their families typically make decisions without understanding either the severity of illness or the efficacy of life-supporting treatments at the end of life. Japanese culture traditionally directs the family to make decisions for the patient. This descriptive study examined the influence of the experiences of 391 Japanese nurses caring for dying patients and family members and how that experience changed their decision making for themselves and their family members. The results were mixed but generally supported the idea that the more experience nurses have in caring for the dying, the less likely they would choose to institute lifesupport measures for themselves and family members. The results have implications for discussions on end-of-life care. © The Author(s) 2016.

  1. Life Cycle Costing as an Aid in Decision Making

    ERIC Educational Resources Information Center

    Blake, Robert

    1973-01-01

    Within an accepted process and measures framework, total program cost over the life of the program, including the life of facility(ies) that house the program, provides a rational decisionmaking environment for the accountable managers. (Author)

  2. End-of-life care decisions in the pediatric intensive care unit: roles professionals play

    PubMed Central

    Michelson, Kelly Nicole; Patel, Rachna; Haber-Barker, Natalie; Emanuel, Linda; Frader, Joel

    2014-01-01

    Objective Describe the roles and respective responsibilities of pediatric intensive care unit (PICU) health care professionals (HCPs) in end-of-life care decisions faced by PICU parents. Design Retrospective qualitative study Setting University based tertiary care children’s hospital Participants Eighteen parents of children who died in the PICU and 48 PICU HCPs (physicians, nurses, social workers, child-life specialists, chaplains, and case managers). Interventions In depth, semi-structured focus groups and one-on-one interviews designed to explore experiences in end-of-life care decision making. Measurements and Main Results We identified end-of-life care decisions that parents face based on descriptions by parents and HCPs. Participants described medical and non-medical decisions addressed toward the end of a child’s life. From the descriptions, we identified seven roles HCPs play in end-of-life care decisions. The family supporter addresses emotional, spiritual, environmental, relational and informational family needs in a nondirective way. The family advocate helps families articulate their views and needs to HCPs. The information giver provides parents with medical information, identifies decisions or describes available options, and clarifies parents’ understanding. The general care coordinator helps facilitate interactions among HCPs in the PICU, among HCPs from different subspecialty teams, and between HCPs and parents. The decision maker makes or directly influences the defined plan of action. The end-of-life care coordinator organizes and executes functions occurring directly before, during and after dying/death. The point person develops a unique trusting relationship with parents. Conclusions Our results describe a framework for HCPs’ roles in parental end-of-life care decision making in the PICU that includes directive, value-neutral and organizational roles. More research is needed to validate these roles. Actively ensuring attention to these

  3. Medical end-of-life decisions: experiences and attitudes of Belgian pediatric intensive care nurses.

    PubMed

    Inghelbrecht, Els; Bilsen, Johan; Pereth, Heidi; Ramet, José; Deliens, Luc

    2009-03-01

    To investigate Belgian pediatric intensive care nurses' involvement in and attitudes toward medical end-of-life decisions with a possible or certain life-shortening effect. Questionnaires were distributed to 141 nurses working in 5 of the 7 pediatric intensive care units in Belgium. Nurses were asked to recall the last child in their care whose treatment involved an end-of-life decision and to describe anonymously their involvement in the decision. Attitudes were ascertained by means of statements and a Likert scale. Questionnaires were completed by 89 nurses (63%). During the preceding 2 years, 76 (85%) had cared for at least 1 child for whom a medical end-of-life decision had been made. Nurses were involved in initiating the decision in 17% of cases, participated in decision making in 50%, and played a role in carrying out the decision in 90%. Only 6% of nurses found it always ethically wrong to hasten the death of a child by administering lethal drugs; most nurses (78%) reported they were prepared to cooperate in administering life-ending drugs in some cases. Most (89%) favored adapting the law, making life termination of children legally possible in certain cases. Belgian pediatric intensive care nurses are often involved in carrying out medical end-of-life decisions, including administration of life-ending drugs, whereas their participation in decision making is more limited. Most think that the current euthanasia law should be extended to minors so that administering life-ending drugs would be possible for terminally ill children in specific circumstances.

  4. Education, Information, and Smoking Decisions: Evidence from Smoking Histories in the United States, 1940-2000

    ERIC Educational Resources Information Center

    de Walque, Damien

    2010-01-01

    This paper tests the hypothesis that education improves health and increases life expectancy. The analysis of smoking histories shows that after 1950, when information about the dangers of tobacco started to diffuse, the prevalence of smoking declined earlier and most dramatically for college graduates. I construct panels based on smoking…

  5. Education, Information, and Smoking Decisions: Evidence from Smoking Histories in the United States, 1940-2000

    ERIC Educational Resources Information Center

    de Walque, Damien

    2010-01-01

    This paper tests the hypothesis that education improves health and increases life expectancy. The analysis of smoking histories shows that after 1950, when information about the dangers of tobacco started to diffuse, the prevalence of smoking declined earlier and most dramatically for college graduates. I construct panels based on smoking…

  6. Seed germination and life history syndromes in the California chaparral

    USGS Publications Warehouse

    Keeley, J.E.

    1991-01-01

    Syndromes are life history responses that are correlated to environmental regimes and are shared by a group of species (Stebbins, 1974). In the California chaparral there are two syndromes contrasted by the timing of seedling recruitment relative to wildfires. One syndrome, here called the fire-recruiter or refractory seed syndrome, includes species (both resprouting and non-resprouting) which share the feature that the timing of seedling establishment is specialized to the first rainy season after fire. Included are woody, suffrutescent and annual life forms but no geophytes have this syndrome. These species are linked by the characteristic that their seeds have a dormancy which is readily broken by environmental stimuli such as intense heat shock or chemicals leached from charred wood. Such seeds are referred to as “refractory” and dormancy, in some cases, is due to seed coat impermeability (such seeds are commonly called hardseeded), but in other cases the mechanism is unknown. Seeds of some may require cold stratification and/or light in addition to fire related stimuli. In the absence of fire related cues, a portion or all of a species’ seed pool remains dormant. Most have locally dispersed seeds that persist in the soil seed bank until the site burns. Dispersal of propagules is largely during spring and summer which facilitates the avoidance of flowering and fruiting during the summer and fall drought. Within a life form (e.g., shrub, suffrutescent, etc.), the seeds of these species have less mass than those of species with non-refractory seeds and this possibly reflects the environmental favorableness of the postfire environment for seedling establishment. Regardless of when fire occurs, germination is normally delayed until late winter or early spring. In the absence of fire, or other disturbance, opportunities for population expansion are largely lacking for species with this syndrome. The other syndrome, here called the fire-resister or non

  7. Life history plasticity and population regulation in sea otters

    USGS Publications Warehouse

    Monson, Daniel H.; Estes, James A.; Bodkin, James L.; Siniff, Donald B.

    2000-01-01

    We contrasted body condition, and age-specific reproduction and mortality between a growing population of sea otters (Enhydralutris) at Kodiak Island and a high-density near-equilibrium population at Amchitka Island, Alaska. We obtained data from marked individuals, population surveys, and collections of beach-cast carcasses. Mass:length ratios indicated that females (but not males) captured in 1992 at Amchitka were in poorer condition than those captured at Kodiak in 1986–1987. In 1993, the condition of females at Amchitka improved in apparent response to two factors: (1) an episodic influx of Pacific smooth lumpsuckers, Aptocyclus ventricocus, from the epi-pelagic zone, which otters consumed; and (2) an increase in the otters’ benthic invertebrate prey resulting from declining otter numbers. Reproductive rates varied with age (0.37 [CI=0.21 to 0.53] births female−1 yr−1 for 2–3-yr-olds, and 0.83 [CI=0.69 to 0.90] for females ≥4 yr old), and were similar at both areas. Weaning success (pups surviving to ≥120 d), in contrast, was almost 50% lower at Amchitka than at Kodiak and for females ≥4 yr of age was 0.52 (CI=0.38 to 0.66) vs 0.94 (CI=0.75 to 0.99), respectively. Sixty-two percent of the preweaning pup losses at Amchitka occurred within a month of parturition and 79% within two months. Postweaning survival was also low at Amchitka as only 18% of instrumented pups were known to be alive one year after mother-pup separation. Adult survival rates appeared similar at Amchitka and Kodiak. Factors affecting survival early in life thus are a primary demographic mechanism of population regulation in sea otters. By maintaining uniformly high reproductive rates over time and limiting investment in any particular reproductive event, sea otters can take advantage of unpredictable environmental changes favorable to pup survival. This strategy is consistent with predictions of “bet-hedging” life history models.

  8. Treatment decision making for adolescents with familial hypercholesterolemia: Role of family history and past experiences.

    PubMed

    Mackie, Thomas I; Tse, Lisa L; de Ferranti, Sarah D; Ryan, Heather R; Leslie, Laurel K

    2015-01-01

    Adolescents and young adults (AYAs) with familial hypercholesterolemia (FH) are at high risk for underdiagnosis and inadequate treatment. Yet, little is known about the factors that influence the medical decision making of AYAs with FH and their families. This study explores how family medical history, family narratives of medical experiences, and AYA medical experiences together function as "experiential evidence" and influence screening and treatment decisions. Twenty-four parents and AYAs affected by FH from a pediatric preventive cardiology practice responded to a survey and a semistructured qualitative interview. Transcribed interviews were analyzed using a modified grounded theory approach. Study design, instruments, and interpretation of results were informed by a 20-member stakeholder panel. AYAs and parents reported extensive personal and family experiences with cholesterol and cardiovascular conditions and treatments, sometimes distinct from FH, which were used as evidence to inform their own perceptions of FH risk and treatment. This experiential evidence impacted perceptions of: (1) hereditary risk for FH diagnoses, (2) risk for future cardiovascular disease, (3) risks associated with treatments, and (4) capacity to comply with recommended treatments. Although experiences of family members initially informed screening and treatment decisions, the subsequent personal experiences of AYAs led to new experiential evidence that informed future decisions. Family cardiovascular history related to and distinct from FH influenced screening and treatment decisions of AYAs and parents affected by FH. Additional clinical assessment of personal and family medical experiences may enhance understanding of the decision-making processes among AYAs and ultimately improve adherence to screening and treatment recommendations. Copyright © 2015 National Lipid Association. Published by Elsevier Inc. All rights reserved.

  9. A Life History of a Korean Adolescent Girl Who Attempted Suicide

    ERIC Educational Resources Information Center

    Yang, Sungeun

    2012-01-01

    The present study explores the life history of a South Korean adolescent girl who attempted suicide. The study focuses on how sociocultural values affected her suicide attempt and how she made meaning out of the experience. The results revealed that her life history was a process of seeking independence and autonomy, and freeing herself from…

  10. Application of Diversity Indices to Quantify Early Life-History Diversity for Chinook Salmon

    SciTech Connect

    Johnson, Gary E.; Sather, Nichole K.; Skalski, John R.; Teel, David

    2014-03-01

    We developed an index of early life history diversity (ELHD) for Pacific salmon (Oncorhynchus spp.) Early life history diversity is the variation in morphological and behavioral traits expressed within and among populations by individual juvenile salmon during their downstream migration. A standard quantitative method does not exist for this prominent concept in salmon biology.

  11. Can life history predict the effect of demographic stochasticity on extinction risk?

    PubMed

    Jeppsson, Tobias; Forslund, Pär

    2012-06-01

    Demographic stochasticity is important in determining extinction risks of small populations, but it is largely unknown how its effect depends on the life histories of species. We modeled effects of demographic stochasticity on extinction risk in a broad range of generalized life histories, using matrix models and branching processes. Extinction risks of life histories varied greatly in their sensitivity to demographic stochasticity. Comparing life histories, extinction risk generally increased with increasing fecundity and decreased with higher ages of maturation. Effects of adult survival depended on age of maturation. At lower ages of maturation, extinction risk peaked at intermediate levels of adult survival, but it increased along with adult survival at higher ages of maturation. These differences were largely explained by differences in sensitivities of population growth to perturbations of life-history traits. Juvenile survival rate contributed most to total demographic variance in the majority of life histories. Our general results confirmed earlier findings, suggesting that empirical patterns can be explained by a relatively simple model. Thus, basic life-history information can be used to assign life-history-specific sensitivity to demographic stochasticity. This is of great value when assessing the vulnerability of small populations.

  12. Consilience and Life History Theory: From Genes to Brain to Reproductive Strategy

    ERIC Educational Resources Information Center

    Figueredo, Aurelio Jose; Vasquez, Geneva; Brumbach, Barbara H.; Schneider, Stephanie M. R.; Sefcek, Jon A.; Tal, Ilanit R.; Hill, Dawn; Wenner, Christopher J.; Jacobs, W. Jake

    2006-01-01

    We describe an integrated theory of individual differences that traces the behavioral development of life history from genes to brain to reproductive strategy. We provide evidence that a single common factor, the K-Factor, underpins a variety of life-history parameters, including an assortment of sexual, reproductive, parental, familial, and…

  13. Life History Theory and Social Deviance: The Mediating Role of Executive Function

    ERIC Educational Resources Information Center

    Wenner, C. J.; Bianchi, J.; Figueredo, A. J.; Rushton, J. Philippe; Jacobs, W. J.

    2013-01-01

    The present work examined predicted relations among Life History strategies, Executive Functions, socially antagonistic attitudes, socially antagonistic behaviors, and general intelligence. Life History (LH) theory predicts that Executive Functions and socially antagonistic attitudes and behaviors underpin an interrelated and coherent set of…

  14. Consilience and Life History Theory: From Genes to Brain to Reproductive Strategy

    ERIC Educational Resources Information Center

    Figueredo, Aurelio Jose; Vasquez, Geneva; Brumbach, Barbara H.; Schneider, Stephanie M. R.; Sefcek, Jon A.; Tal, Ilanit R.; Hill, Dawn; Wenner, Christopher J.; Jacobs, W. Jake

    2006-01-01

    We describe an integrated theory of individual differences that traces the behavioral development of life history from genes to brain to reproductive strategy. We provide evidence that a single common factor, the K-Factor, underpins a variety of life-history parameters, including an assortment of sexual, reproductive, parental, familial, and…

  15. A Life History Assessment of Early Childhood Sexual Abuse in Women

    ERIC Educational Resources Information Center

    Vigil, Jacob M.; Geary, David C.; Byrd-Craven, Jennifer

    2005-01-01

    Life history theory provided a framework for examining the relations among child sexual abuse (CSA), childhood adversity, and patterns of reproductive development and behavior. A community survey that assessed CSA, life history variables (e.g., age of menarche), and social and family background was administered to 623 women (mean age=26.9 years).…

  16. The Treatment of Geological Time & the History of Life on Earth in High School Biology Textbooks

    ERIC Educational Resources Information Center

    Summers, Gerald; Decker, Todd; Barrow, Lloyd

    2007-01-01

    In spite of the importance of geological time in evolutionary biology, misconceptions about historical events in the history of life on Earth are common. Glenn (1990) has documented a decline from 1960 to 1989 in the amount of space devoted to the history of life in high school earth science textbooks, but we are aware of no similar study in…

  17. The Treatment of Geological Time & the History of Life on Earth in High School Biology Textbooks

    ERIC Educational Resources Information Center

    Summers, Gerald; Decker, Todd; Barrow, Lloyd

    2007-01-01

    In spite of the importance of geological time in evolutionary biology, misconceptions about historical events in the history of life on Earth are common. Glenn (1990) has documented a decline from 1960 to 1989 in the amount of space devoted to the history of life in high school earth science textbooks, but we are aware of no similar study in…

  18. Life History Theory and Social Deviance: The Mediating Role of Executive Function

    ERIC Educational Resources Information Center

    Wenner, C. J.; Bianchi, J.; Figueredo, A. J.; Rushton, J. Philippe; Jacobs, W. J.

    2013-01-01

    The present work examined predicted relations among Life History strategies, Executive Functions, socially antagonistic attitudes, socially antagonistic behaviors, and general intelligence. Life History (LH) theory predicts that Executive Functions and socially antagonistic attitudes and behaviors underpin an interrelated and coherent set of…

  19. Life history traits to predict biogeographic species distributions in bivalves

    NASA Astrophysics Data System (ADS)

    Montalto, V.; Rinaldi, A.; Sarà, G.

    2015-10-01

    Organismal fecundity ( F) and its relationship with body size (BS) are key factors in predicting species distribution under current and future scenarios of global change. A functional trait-based dynamic energy budget (FT-DEB) is proposed as a mechanistic approach to predict the variation of F and BS as function of environmental correlates using two marine bivalves as model species ( Mytilus galloprovincialis and Brachidontes pharaonis). Validation proof of model skill (i.e., degree of correspondence between model predictions and field observations) and stationarity (i.e., ability of a model generated from data collected at one place/time to predict processes at another place/time) was provided to test model performance in predicting the bivalve distribution throughout the 22 sites in the Central Mediterranean Sea under local conditions of food density and body temperature. Model skill and stationarity were tested through the estimate of commission (i.e., proportion of species' absences predicted present) and omission (i.e., proportion of presences predicted absent) errors of predictions by comparing mechanistic predicted vs. observed F and BS values throughout the study area extrapolated by lab experiments and literature search. The resulting relationship was reliable for both species, and body size and fecundity were highly correlated in M. galloprovincialis compared to B. pharaonis; FT-DEB showed correct predictions of presence in more than 75 % of sites, and the regression between BS predicted vs. observed was highly significant in both species. Whilst recognising the importance of biotic interactions in shaping the distribution of species, our FT-DEB approach provided reliable quantitative estimates of where our species had sufficient F to support local populations or suggesting reproductive failure. Mechanistically, estimating F and BS as key traits of species life history can also be addressed within a broader, scale-dependent context that surpasses the

  20. Integration of manatee life-history data and population modeling

    USGS Publications Warehouse

    Eberhardt, L.L.; O'Shea, Thomas J.; O'Shea, Thomas J.; Ackerman, B.B.; Percival, H. Franklin

    1995-01-01

    Aerial counts and the number of deaths have been a major focus of attention in attempts to understand the population status of the Florida manatee (Trichechus manatus latirostris). Uncertainties associated with these data have made interpretation difficult. However, knowledge of manatee life-history attributes increased and now permits the development of a population model. We describe a provisional model based on the classical approach of Lotka. Parameters in the model are based on data from'other papers in this volume and draw primarily on observations from the Crystal River, Blue Spring, and Adantic Coast areas. The model estimates X (the finite rate ofincrease) at each study area, and application ofthe delta method provides estimates of variance components and partial derivatives ofX with respectto key input parameters (reproduction, adult survival, and early survival). In some study areas, only approximations of some parameters are available. Estimates of X and coefficients of variation (in parentheses) of manatees were 1.07 (0.009) in the Crystal River, 1.06 (0.012) at Blue Spring, and 1.01 (0.012) on the Atlantic Coast. Changing adult survival has a major effect on X. Early-age survival has the smallest effect. Bootstrap comparisons of population growth estimates from trend counts in the Crystal River and at Blue Spring and the reproduction and survival data suggest that the higher, observed rates from counts are probably not due to chance. Bootstrapping for variance estimates based on reproduction and survival data from manatees at Blue Spring and in the Crystal River provided estimates of X, adult survival, and rates of reproduction that were similar to those obtained by other methods. Our estimates are preliminary and suggestimprovements for future data collection and analysis. However, results support efforts to reduce mortality as the most effective means to promote the increased growth necessary for the eventual recovery of the Florida manatee

  1. Social learning improves survivorship at a life-history transition.

    PubMed

    Manassa, R P; McCormick, M I

    2013-04-01

    During settlement, one of the main threats faced by individuals relates to their ability to detect and avoid predators. Information on predator identities can be gained either through direct experience or from the observation and/or interaction with others, a process known as social learning. In this form of predator recognition, less experienced individuals learn from experienced members within the social group, without having to directly interact with a predator. In this study, we examined the role of social learning in predator recognition in relation to the survival benefits for the damselfish, Pomacentrus wardi, during their settlement transition. Specifically, our experiments aimed to determine if P. wardi are capable of transmitting the recognition of the odour of a predator, Pseudochromis fuscus, to conspecifics. The experiment also examined whether there was a difference in the rate of survival between individuals that directly learnt the predator odour and those which acquired the information through social learning compared to naïve individuals. Results show that naïve P. wardi are able to learn a predator's identity from experienced individuals via social learning. Furthermore, survival between individuals that directly learnt the predator's identity and those that learnt through social learning did not significantly differ, with fish from both treatments surviving at least five times better than controls. These results demonstrate that experience may play a vital role in determining the outcome of predator-prey interactions, highlighting that social learning improves the ability of prey to avoid and/or escape predation at a life-history transition.

  2. Life history traits to predict biogeographic species distributions in bivalves.

    PubMed

    Montalto, V; Rinaldi, A; Sarà, G

    2015-10-01

    Organismal fecundity (F) and its relationship with body size (BS) are key factors in predicting species distribution under current and future scenarios of global change. A functional trait-based dynamic energy budget (FT-DEB) is proposed as a mechanistic approach to predict the variation of F and BS as function of environmental correlates using two marine bivalves as model species (Mytilus galloprovincialis and Brachidontes pharaonis). Validation proof of model skill (i.e., degree of correspondence between model predictions and field observations) and stationarity (i.e., ability of a model generated from data collected at one place/time to predict processes at another place/time) was provided to test model performance in predicting the bivalve distribution throughout the 22 sites in the Central Mediterranean Sea under local conditions of food density and body temperature. Model skill and stationarity were tested through the estimate of commission (i.e., proportion of species' absences predicted present) and omission (i.e., proportion of presences predicted absent) errors of predictions by comparing mechanistic predicted vs. observed F and BS values throughout the study area extrapolated by lab experiments and literature search. The resulting relationship was reliable for both species, and body size and fecundity were highly correlated in M. galloprovincialis compared to B. pharaonis; FT-DEB showed correct predictions of presence in more than 75 % of sites, and the regression between BS predicted vs. observed was highly significant in both species. Whilst recognising the importance of biotic interactions in shaping the distribution of species, our FT-DEB approach provided reliable quantitative estimates of where our species had sufficient F to support local populations or suggesting reproductive failure. Mechanistically, estimating F and BS as key traits of species life history can also be addressed within a broader, scale-dependent context that surpasses the

  3. Life history, cognition and the evolution of complex foraging niches.

    PubMed

    Schuppli, Caroline; Graber, Sereina M; Isler, Karin; van Schaik, Carel P

    2016-03-01

    Animal species that live in complex foraging niches have, in general, improved access to energy-rich and seasonally stable food sources. Because human food procurement is uniquely complex, we ask here which conditions may have allowed species to evolve into such complex foraging niches, and also how niche complexity is related to relative brain size. To do so, we divided niche complexity into a knowledge-learning and a motor-learning dimension. Using a sample of 78 primate and 65 carnivoran species, we found that two life-history features are consistently correlated with complex niches: slow, conservative development or provisioning of offspring over extended periods of time. Both act to buffer low energy yields during periods of learning, and may thus act as limiting factors for the evolution of complex niches. Our results further showed that the knowledge and motor dimensions of niche complexity were correlated with pace of development in primates only, and with the length of provisioning in only carnivorans. Accordingly, in primates, but not carnivorans, living in a complex foraging niche requires enhanced cognitive abilities, i.e., a large brain. The patterns in these two groups of mammals show that selection favors evolution into complex niches (in either the knowledge or motor dimension) in species that either develop more slowly or provision their young for an extended period of time. These findings help to explain how humans constructed by far the most complex niche: our ancestors managed to combine slow development (as in other primates) with systematic provisioning of immatures and even adults (as in carnivorans). This study also provides strong support for the importance of ecological factors in brain size evolution. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. The life history of a botulinum toxin molecule.

    PubMed

    Simpson, Lance

    2013-06-01

    There is an emerging literature describing the absorption, distribution, metabolism and elimination of botulinum toxin. This work reveals that the toxin can be absorbed by both the oral and inhalation routes. The primary mechanism for absorption is binding and transport across epithelial cells. Toxin that enters the body undergoes a distribution phase, which is quite short, and an elimination phase, which is comparatively long. During the distribution phase, botulinum toxin migrates to the peri-neuronal microcompartment in the vicinity of vulnerable cells, such as cholinergic nerve endings. Only these cells have the ability to selectively accumulate the molecule. When the toxin moves from the cell membrane to the cell interior, it undergoes programmed death. This is coincident with release of the catalytically active light chain that paralyzes transmission. Intraneuronal metabolism of light chain is via the ubiquitination-proteasome pathway. Systemic metabolism and elimination is assumed to be via the liver. The analysis of absorption, distribution, metabolism and elimination of the toxin helps to create a life history of the molecule in the body. This has many benefits, including: a) clarifying the mechanisms that underlie the disease botulism, b) providing insights for development of medical countermeasures against the toxin, and c) helping to explain the meaning of a lethal dose of toxin. It is likely that work intended to enhance understanding of the fate of botulinum toxin in the body will intensify. These efforts will include new and powerful analytic tools, such as single molecule-single cell analyses in vitro and real time, 3-dimensional pharmacokinetic studies in vivo. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. Searching for a life history approach to salmon escapement management

    USGS Publications Warehouse

    Knudsen, E.E.; Symmes, E.W.; Margraf, F.J.

    2003-01-01

    A number of Pacific salmon populations have already been lost and many others throughout the range are in various states of decline. Recent research has documented that Pacific salmon carcasses serve as a key delivery vector of marine-derived nutrients into the freshwater portions of their ecosystems. This nutrient supply plays a critical biological feedback role in salmon sustainability by supporting juvenile salmon production. We first demonstrate how nutrient feedback potential to juvenile production may be unaccounted for in spawner-recruit models of populations under long-term exploitation. We then present a heuristic, life history-based, spreadsheet survival model that incorporates salmon carcass-driven nutrient feedback to the freshwater components of the salmon ecosystem. The productivity of a hypothetical coho salmon population was simulated using rates from the literature for survival from spawner to egg, egg to fry, fry to smolt, and smolt to adult. The effects of climate variation and nutrient feedback on survival were incorporated, as were density-dependent effects of the numbers of spawners and fry on freshwater survival of eggs and juveniles. The unexploited equilibrium population was subjected to 100 years of 20, 40, 60, and 80% harvest. Each harvest scenario greater than 20% brought the population to a reduced steady state, regardless of generous compensatory survival at low population sizes. Increasing harvest reduced the positive effects of nutrient contributions to population growth. Salmon researchers should further explore this modeling approach for establishing escapement goals. Given the importance of nutrient feedback, managers should strive for generous escapements that support nutrient rebuilding, as well as egg deposition, to ensure strong future salmon production.

  6. What parents want from doctors in end-of-life decision-making for children.

    PubMed

    Sullivan, J; Monagle, P; Gillam, L

    2014-03-01

    End-of-life decision-making is difficult for everyone involved, as many studies have shown. Within this complexity, there has been little information on how parents see the role of doctors in end-of-life decision-making for children. This study aimed to examine parents' views and experiences of end-of-life decision-making. A qualitative method with a semistructured interview design was used. Parent participants were living in the community. Twenty-five bereaved parents. Parents reported varying roles taken by doctors: being the provider of information without opinion; giving information and advice as to the decision that should be taken; and seemingly being the decision maker for the child. The majority of parents found their child's doctor enabled them to be the ultimate decision maker for their child, which was what they very clearly wanted to be, and consequently enabled them to exercise their parental autonomy. Parents found it problematic when doctors took over decision-making. A less frequently reported, yet significant role for doctors was to affirm decisions after they had been made by parents. Other important aspects of the doctor's role were to provide follow-up support and referral. Understanding the role that doctors take in end-of-life decisions, and the subsequent impact of that role from the perspective of parents can form the basis of better informed clinical practice.

  7. Intellectual Disabilities and Decision Making at End of Life: A Literature Review.

    PubMed

    Kirkendall, Abbie; Linton, Kristen; Farris, Saritha

    2016-07-25

    Individuals with an intellectual disability are vulnerable to having end-of-life decisions made for them merely due to the presence of a disability. As a result, decisions made by others may not reflect the exact wishes of the individual. This review examines literature on individuals with an intellectual disability in making end-of-life decisions from the years 2000 to 2014. A total of 38 articles were found with 12 articles having a direct focus on end-of-life decision making. The emerging themes include the following: (i) assumption of lack of capacity, (ii) inconsistency in evaluating capacity and communication challenges and (iii) third party decisions. Earlier discussions about end-of-life planning before the diagnosis of a life-limiting illness would be beneficial. Lacking is a consistent approach to determining capacity for individuals with an intellectual disability. The findings from this review provide a foundation for a decision tree in end-of-life decision making for individuals with an intellectual disability. © 2016 John Wiley & Sons Ltd.

  8. Deconstructing environmental predictability: seasonality, environmental colour and the biogeography of marine life histories.

    PubMed

    Marshall, Dustin J; Burgess, Scott C

    2015-02-01

    Environmental predictability is predicted to shape the evolution of life histories. Two key types of environmental predictability, seasonality and environmental colour, may influence life-history evolution independently but formal considerations of both and how they relate to life history are exceedingly rare. Here, in a global biogeographical analysis of over 800 marine invertebrates, we explore the relationships between both forms of environmental predictability and three fundamental life-history traits: location of larval development (aplanktonic vs. planktonic), larval developmental mode (feeding vs. non-feeding) and offspring size. We found that both dispersal potential and offspring size related to environmental predictability, but the relationships depended on both the environmental factor as well as the type of predictability. Environments that were more seasonal in food availability had a higher prevalence of species with a planktonic larval stage. Future studies should consider both types of environmental predictability as each can strongly affect life-history evolution. © 2014 John Wiley & Sons Ltd/CNRS.

  9. Life Histories of Selected Caddisflies (Trichoptera) in an Ozark Stream, U.S.A.

    DTIC Science & Technology

    1990-04-01

    Brooks AFB TX 78235-5301 NIA______ N/A_____ N/A_____N/A___ 1 11. TITLE (include Security Classification) SLife histories of selected caddisflies ...LIFE HISTORIES OF SELECTED CADDISFLIES (TRICHOPTERA) IN AN OZARK STREAM, U. S. A. 1 Accession Fr David E. Bowles 2,3 and Robert T. Allen NTIS *.. DTIC...8217 , Running head: Life histories of Ozark caddisflies . 1 Approved for publication by the Director, Arkansas Agriculturalq e Experiment Station, University

  10. Supporting end of life decision making: Case studies of relational closeness in supported decision making for people with severe or profound intellectual disability.

    PubMed

    Watson, Joanne; Wilson, Erin; Hagiliassis, Nick

    2017-08-16

    The United Nations Convention on the Rights of Persons with Disabilities (UNCRPD) promotes the use of supported decision making in lieu of substitute decision making. To date, there has been a lack of focus on supported decision making for people with severe or profound intellectual disability, including for end of life decisions. Five people with severe or profound intellectual disability's experiences of supported decision making were examined. This article is particularly focused on one participant's experiences at the end of his life. All five case studies identified that supporters were most effective in providing decision-making support for participants when they were relationally close to the person and had knowledge of the person's life story, particularly in relation to events that demonstrated preference. Findings from this study provide new understandings of supported decision making for people with severe or profound intellectual disability and have particular relevance for supporting decision making at the end of life. © 2017 John Wiley & Sons Ltd.

  11. Skagit River coho salmon life history model—Users’ guide

    USGS Publications Warehouse

    Woodward, Andrea; Kirby, Grant; Morris, Scott

    2017-09-29

    Natural resource management is conducted in the context of multiple anthropogenic stressors and is further challenged owing to changing climate. Experiments to determine the effects of climate change on complex ecological systems are nearly impossible. However, using a simulation model to synthesize current understanding of key ecological processes through the life cycle of a fish population can provide a platform for exploring potential effects of and management responses to changing conditions. Potential climate-change scenarios can be imposed, responses can be observed, and the effectiveness of potential actions can be evaluated. This approach is limited owing to future conditions likely deviating in range and timing from conditions used to create the model so that the model is expected to become obsolete. In the meantime, however, the modeling process explicitly states assumptions, clarifies information gaps, and provides a means to better understand which relationships are robust and which are vulnerable to changing climate by observing whether and why model output diverges from actual observations through time. The purpose of the model described herein is to provide such a decision-support tool regarding coho (Oncorhynchus kisutch) salmon for the Sauk-Suiattle Indian Tribe of Washington State.The Skagit coho salmon model is implemented in a system dynamics format and has three primary stocks—(1) predicted smolts, (2) realized smolts, and (3) escapement. “Predicted smolts” are the number of smolts expected based on the number of spawners in any year and the Ricker production curve. Pink salmon (Oncorhynchus gorbuscha) return to the Skagit River in odd years, and when they overlap with juvenile rearing coho salmon, coho smolt production is substantially higher than in non-pink years. Therefore, the model uses alternative Ricker equations to predict smolts depending on whether their juvenile year was a pink or non-pink year. The stock “realized smolts

  12. Communication nonaccommodation in family conversations about end-of-life health decisions.

    PubMed

    Scott, Allison M; Caughlin, John P

    2015-01-01

    Furthering our understanding of how communication can improve end-of-life decision making requires a shift in focus from whether people talk to how people talk about end-of-life health decisions. This study used communication accommodation theory to examine the extent to which communication nonaccommodation distinguished more from less successful end-of-life conversations among family members. We analyzed elicited conversations about end-of-life health decisions from 121 older parent/adult child dyads using outside ratings of communication over- and underaccommodation and self-reported conversational outcomes. Results of multilevel linear modeling revealed that outside ratings of underaccommodation predicted self-reported and partner-reported uncertainty, and ratings of overaccommodation predicted self-reported decision-making efficacy and change in concordance accuracy. We discuss the methodological, theoretical, and practical implications of these findings.

  13. Human evolution, life history theory, and the end of biological reproduction.

    PubMed

    Last, Cadell

    2014-01-01

    Throughout primate history there have been three major life history transitions towards increasingly delayed sexual maturation and biological reproduction, as well as towards extended life expectancy. Monkeys reproduce later and live longer than do prosimians, apes reproduce later and live longer than do monkeys, and humans reproduce later and live longer than do apes. These life history transitions are connected to increased encephalization. During the last life history transition from apes to humans, increased encephalization co-evolved with increased dependence on cultural knowledge for energy acquisition. This led to a dramatic pressure for more energy investment in growth over current biological reproduction. Since the industrial revolution socioeconomic development has led to even more energy being devoted to growth over current biological reproduction. I propose that this is the beginning of an ongoing fourth major primate life history transition towards completely delayed biological reproduction and an extension of the evolved human life expectancy. I argue that the only fundamental difference between this primate life history transition and previous life history transitions is that this transition is being driven solely by cultural evolution, which may suggest some deeper evolutionary transition away from biological evolution is already in the process of occurring.

  14. Life History Consequences of the Facultative Expression of a Dispersal Life Stage in the Phoretic Bulb Mite (Rhizoglyphus robini)

    PubMed Central

    Deere, Jacques A.; Coulson, Tim; Smallegange, Isabel M.

    2015-01-01

    Life history traits play an important role in population dynamics and correlate, both positively and negatively, with dispersal in a wide range of taxa. Most invertebrate studies on trade-offs between life history traits and dispersal have focused on dispersal via flight, yet much less is known about how life history trade-offs influence species that disperse by other means. In this study, we identify effects of investing in dispersal morphology (dispersal expression) on life history traits in the male dimorphic bulb mite (Rhizoglyphus robini). This species has a facultative juvenile life stage (deutonymph) during which individuals can disperse by phoresy. Further, adult males are either fighters (which kill other mites) or benign scramblers. Here, in an experiment, we investigate the effects of investing in dispersal on size at maturity, sex and male morph ratio, and female lifetime reproductive success. We show that life history traits correlate negatively with the expression of the dispersal stage. Remarkably, all males that expressed the dispersal life stage developed into competitive fighters and none into scramblers. This suggests that alternative, male reproductive strategies and dispersal should not be viewed in isolation but considered concurrently. PMID:26325395

  15. Acutely-bereaved Surrogates' Stories about the Decision to Limit Life Support in the ICU

    PubMed Central

    Nunez, Eduardo R.; Schenker, Yael; Joel, Ian D.; Reynolds, Charles F.; Dew, Mary Amanda; Arnold, Robert M.; Barnato, Amber E.

    2015-01-01

    Objective Participating in a decision to limit life support for a loved one in the intensive care unit (ICU) is associated with adverse mental health consequences for surrogate decision makers. We sought to describe acutely-bereaved surrogates' experiences surrounding this decision. Design and setting Secondary analysis of interviews with surrogates approximately 4 weeks after a patient's death in one of 6 ICUs at 4 hospitals in Pittsburgh, Pennsylvania. Subjects Adults who participated in decisions about life support in the ICU. Interventions n/a Measurements We collected participant demographics, prior advance care planning, and decision control preferences. We used qualitative content analysis of transcribed interviews to identify themes in surrogates' experiences. Main results The 23 participants included the spouse (n=7), child/step-child (7), sibling (5), parent (3), or other relation (1) of the deceased patient. Their mean age was 55, 61% were women, all were white, 74% had prior treatment preferences discussions with the patient and 43% of patients had written advance directives. 15/23 (65%) surrogates preferred an active decision-making role, 8/23 (35%) preferred to share responsibility with the physician and no surrogates preferred a passive role. Surrogates report that key stressors in the ICU are the uncertainty and witnessed or empathic suffering. These factors contributed to surrogates' sense of helplessness in the ICU. Involvement in the decision to limit life support allowed surrogates to regain a sense of agency by making a decision consistent with the patient's wishes and values, counteracting surrogates' helplessness and ending the uncertainty and suffering. Conclusions In this all-white sample of surrogates with non-passive decision control preferences from a single US region, participating in decision making allowed surrogates to regain control, counteract feelings of helplessness, and end their empathic suffering. While prior research

  16. A Review of General Accounting Office Decisions on Life Cycle Costing.

    DTIC Science & Technology

    The report reviews GAO decisions and reports through 1973 which impact on the application of Life Cycle Costing procedures on Government procurements. In addition to a discussion and overview, 35 specific decisions and reports are abstracted and reviewed. Cross-references and indexes by subject area are also provided. (Author)

  17. Relationships between life attitude profile and symptoms experienced with treatment decision evaluation in patients with cancer.

    PubMed

    Erci, Behice; Özdemir, Süreyya

    2013-01-01

    Despite many researches that have examined life attitude profile, treatment decision evaluation, and symptoms experienced in cancer populations, the relationships between life attitude profile and symptoms experienced with treatment decision evaluation are still not well understood. A thorough understanding of these relationships is critical for health care professionals to provide appropriate management to patients. The aim of this study was to determine relationships among life attitude profile, the treatment decision evaluation, and symptoms experienced in Turkish patients with cancer. A convenience sample of 199 patients with cancer at a Turkish university hospital completed a structured questionnaire including demographic characteristics and the Life Attitude Profile-Revised Scale for patients with cancer in 2007. The researchers visited the oncology clinic 5 work days every week and conducted interviews with the patients. The life attitude profile was not correlated with the treatment decision evaluation and symptoms experienced (r = 0.082, r = -026). The treatment decision evaluation showed that the patients were uncertain about their satisfaction with the treatment decision. Significant correlations were found between the treatment decision evaluation and symptoms experienced (r = 0.206; P <.01). Holistic nursing interventions can be implemented as they promote healing of the whole person processes as facilitating self-awareness, living meaningfully, and promotion connection with others and with nature and a higher power.

  18. Social systems and life-history characteristics of mongooses.

    PubMed

    Schneider, Tilman C; Kappeler, Peter M

    2014-02-01

    The diversity of extant carnivores provides valuable opportunities for comparative research to illuminate general patterns of mammalian social evolution. Recent field studies on mongooses (Herpestidae), in particular, have generated detailed behavioural and demographic data allowing tests of assumptions and predictions of theories of social evolution. The first studies of the social systems of their closest relatives, the Malagasy Eupleridae, also have been initiated. The literature on mongooses was last reviewed over 25 years ago. In this review, we summarise the current state of knowledge on the social organisation, mating systems and social structure (especially competition and cooperation) of the two mongoose families. Our second aim is to evaluate the contributions of these studies to a better understanding of mammalian social evolution in general. Based on published reports or anecdotal information, we can classify 16 of the 34 species of Herpestidae as solitary and nine as group-living; there are insufficient data available for the remainder. There is a strong phylogenetic signal of sociality with permanent complex groups being limited to the genera Crossarchus, Helogale, Liberiictis, Mungos, and Suricata. Our review also indicates that studies of solitary and social mongooses have been conducted within different theoretical frameworks: whereas solitary species and transitions to gregariousness have been mainly investigated in relation to ecological determinants, the study of social patterns of highly social mongooses has instead been based on reproductive skew theory. In some group-living species, group size and composition were found to determine reproductive competition and cooperative breeding through group augmentation. Infanticide risk and inbreeding avoidance connect social organisation and social structure with reproductive tactics and life histories, but their specific impact on mongoose sociality is still difficult to evaluate. However, the level

  19. Life history correlates of alternative migratory strategies in American Dippers.

    PubMed

    Gillis, Elizabeth A; Green, David J; Middleton, Holly A; Morrissey, Christy A

    2008-06-01

    Partial migration is thought to be a critical step in the evolution of avian migration, but data on the life history correlates of alternative migratory strategies are extremely limited. We have studied a partially migratory population of American Dippers since 1999. This population is composed of sedentary individuals (residents) that maintain the same territory year round and altitudinal migrants that share winter grounds with residents, but move to higher elevations to breed. We used seven years of data on individually marked birds to (1) determine if individuals consistently use the same migratory strategy, (2) determine if offspring have the same strategy as their parents, and (3) estimate reproductive and survival rates of the two migratory strategies. We evaluate hypotheses for the persistence of partial migration and discuss their implication for the evolution of migration in sedentary populations. Individual American Dippers rarely switched migratory strategy (4/169 monitored more than one year). An individual's strategy, however, was not always that of its parents, indicating that, while migratory behavior may have a genetic component, environmental or social conditions probably influence the migratory strategy that an individual adopts. Sedentary dippers consistently had higher annual productivity (approximately 1.4 more fledglings/year) than migratory dippers, but mark-recapture models suggested that migratory dippers may have slightly higher survival than residents (approximately 3.4%). Migrants were estimated to have lower lifetime reproductive success than residents because their higher survival was insufficient to offset their lower productivity. Our data suggest that alternative migratory strategies in American Dippers are unlikely to be a fixed genetic dimorphism that persists because the two strategies have equal fitness, or because the relative fitness of the two strategies fluctuates over time. Migratory strategies in American Dippers are more

  20. Life history variation in Barents Sea fish: implications for sensitivity to fishing in a changing environment.

    PubMed

    Wiedmann, Magnus A; Primicerio, Raul; Dolgov, Andrey; Ottesen, Camilla A M; Aschan, Michaela

    2014-09-01

    Under exploitation and environmental change, it is essential to assess the sensitivity and vulnerability of marine ecosystems to such stress. A species' response to stress depends on its life history. Sensitivity to harvesting is related to the life history "fast-slow" continuum, where "slow" species (i.e., large, long lived, and late maturing) are expected to be more sensitive to fishing than "fast" ones. We analyze life history traits variation for all common fish species in the Barents Sea and rank fishes along fast-slow gradients obtained by ordination analyses. In addition, we integrate species' fast-slow ranks with ecosystem survey data for the period 2004-2009, to assess life history variation at the community level in space and time. Arctic fishes were smaller, had shorter life spans, earlier maturation, larger offspring, and lower fecundity than boreal ones. Arctic fishes could thus be considered faster than the boreal species, even when body size was corrected for. Phylogenetically related species possessed similar life histories. Early in the study period, we found a strong spatial gradient, where members of fish assemblages in the southwestern Barents Sea displayed slower life histories than in the northeast. However, in later, warmer years, the gradient weakened caused by a northward movement of boreal species. As a consequence, the northeast experienced increasing proportions of slower fish species. This study is a step toward integrating life history traits in ecosystem-based areal management. On the basis of life history traits, we assess the fish sensitivity to fishing, at the species and community level. We show that climate warming promotes a borealization of fish assemblages in the northeast, associated with slower life histories in that area. The biology of Arctic species is still poorly known, and boreal species that now establish in the Arctic are fishery sensitive, which calls for cautious ecosystem management of these areas.

  1. Genetic analysis of life-history constraint and evolution in a wild ungulate population.

    PubMed

    Morrissey, Michael B; Walling, Craig A; Wilson, Alastair J; Pemberton, Josephine M; Clutton-Brock, Tim H; Kruuk, Loeske E B

    2012-04-01

    Trade-offs among life-history traits are central to evolutionary theory. In quantitative genetic terms, trade-offs may be manifested as negative genetic covariances relative to the direction of selection on phenotypic traits. Although the expression and selection of ecologically important phenotypic variation are fundamentally multivariate phenomena, the in situ quantification of genetic covariances is challenging. Even for life-history traits, where well-developed theory exists with which to relate phenotypic variation to fitness variation, little evidence exists from in situ studies that negative genetic covariances are an important aspect of the genetic architecture of life-history traits. In fact, the majority of reported estimates of genetic covariances among life-history traits are positive. Here we apply theory of the genetics and selection of life histories in organisms with complex life cycles to provide a framework for quantifying the contribution of multivariate genetically based relationships among traits to evolutionary constraint. We use a Bayesian framework to link pedigree-based inference of the genetic basis of variation in life-history traits to evolutionary demography theory regarding how life histories are selected. Our results suggest that genetic covariances may be acting to constrain the evolution of female life-history traits in a wild population of red deer Cervus elaphus: genetic covariances are estimated to reduce the rate of adaptation by about 40%, relative to predicted evolutionary change in the absence of genetic covariances. Furthermore, multivariate phenotypic (rather than genetic) relationships among female life-history traits do not reveal this constraint.

  2. Life history variation in Barents Sea fish: implications for sensitivity to fishing in a changing environment

    PubMed Central

    Wiedmann, Magnus A; Primicerio, Raul; Dolgov, Andrey; Ottesen, Camilla A M; Aschan, Michaela

    2014-01-01

    Under exploitation and environmental change, it is essential to assess the sensitivity and vulnerability of marine ecosystems to such stress. A species’ response to stress depends on its life history. Sensitivity to harvesting is related to the life history “fast–slow” continuum, where “slow” species (i.e., large, long lived, and late maturing) are expected to be more sensitive to fishing than “fast” ones. We analyze life history traits variation for all common fish species in the Barents Sea and rank fishes along fast–slow gradients obtained by ordination analyses. In addition, we integrate species’ fast–slow ranks with ecosystem survey data for the period 2004–2009, to assess life history variation at the community level in space and time. Arctic fishes were smaller, had shorter life spans, earlier maturation, larger offspring, and lower fecundity than boreal ones. Arctic fishes could thus be considered faster than the boreal species, even when body size was corrected for. Phylogenetically related species possessed similar life histories. Early in the study period, we found a strong spatial gradient, where members of fish assemblages in the southwestern Barents Sea displayed slower life histories than in the northeast. However, in later, warmer years, the gradient weakened caused by a northward movement of boreal species. As a consequence, the northeast experienced increasing proportions of slower fish species. This study is a step toward integrating life history traits in ecosystem-based areal management. On the basis of life history traits, we assess the fish sensitivity to fishing, at the species and community level. We show that climate warming promotes a borealization of fish assemblages in the northeast, associated with slower life histories in that area. The biology of Arctic species is still poorly known, and boreal species that now establish in the Arctic are fishery sensitive, which calls for cautious ecosystem management of

  3. Theories of Health Care Decision Making at the End of Life: A Meta-Ethnography.

    PubMed

    Kim, Kyounghae; Heinze, Katherine; Xu, Jiayun; Kurtz, Melissa; Park, Hyunjeong; Foradori, Megan; Nolan, Marie T

    2017-08-01

    The aim of this meta-ethnography is to appraise the types and uses of theories relative to end-of-life decision making and to develop a conceptual framework to describe end-of-life decision making among patients with advanced cancers, heart failure, and amyotrophic lateral sclerosis (ALS) and their caregivers or providers. We used PubMed, Embase, and Cumulative Index to Nursing and Allied Health Literature (CINAHL) databases to extract English-language articles published between January 2002 and April 2015. Forty-three articles were included. The most common theories included decision-making models ( n = 14) followed by family-centered ( n = 11) and behavioral change models ( n = 7). A conceptual framework was developed using themes including context of decision making, communication and negotiation of decision making, characteristics of decision makers, goals of decision making, options and alternatives, and outcomes. Future research should enhance and apply these theories to guide research to develop patient-centered decision-making programs that facilitate informed and shared decision making at the end of life among patients with advanced illness and their caregivers.

  4. Sprecies profiles: Life histories and environmental requirements of coastal fishes and invertebrates (Mid-Atlantic): Bluefish

    SciTech Connect

    Pottern, G.B.; Huish, M.T.; Kerby, J.H. )

    1989-02-01

    Species profiles are literature summaries of the taxonomy, morphology, distribution, life history, and environmental requirements of coastal fishes and invertebrates within a specified range. They are written to assist in environmental impact assessment and decision making by coastal planners and developers. Bluefish are the most important recreational fish in the United States, especially in the mid-Atlantic region. The commercial catch is smaller but has increased during recent years. One population spawns offshore during spring from northern Florida to North Carolina, and these young migrate into mid-Atlantic coastal waters to spend their summer and fall. A second population spawns offshore during summer from North Carolina to Massachusetts, but most of these young remain offshore for the remainder of the season. In late fall, young and adults of both populations migrate south until the following spring. Bluefish are migratory, opportunistic, pelagic predators throughout life, and their seasonal abundance may have profound community structuring effects. Schools of juvenile bluefish may be important forage for many pelagic predators, including adults of their own species. Photoperiod apparently triggers long-range migration, and temperature serves as a proximal cue to short-range migration. Bluefish are sensitive to bacterial infection in polluted water and have little tolerance for low oxygen conditions. 55 refs., 6 figs., 3 tabs.

  5. The Decision to Terminate One's Life: Psychoanalytic Thoughts on Suicide.

    ERIC Educational Resources Information Center

    Rangell, Leo

    1988-01-01

    Examination of immediate psychoanalytic surround of decision to commit suicide finds range of motivations circumscribed. Often suicide is external aggression turned against oneself. Loss of love, or hopelessness resulting from chronic or acute lowering of self-regard, allows aggression to dominate one's libido. Manic excitement, immortality…

  6. Life history determines genetic structure and evolutionary potential of host–parasite interactions

    PubMed Central

    Barrett, Luke G.; Thrall, Peter H.; Burdon, Jeremy J.; Linde, Celeste C.

    2009-01-01

    Measures of population genetic structure and diversity of disease-causing organisms are commonly used to draw inferences regarding their evolutionary history and potential to generate new variation in traits that determine interactions with their hosts. Parasite species exhibit a range of population structures and life-history strategies, including different transmission modes, life-cycle complexity, off-host survival mechanisms and dispersal ability. These are important determinants of the frequency and predictability of interactions with host species. Yet the complex causal relationships between spatial structure, life history and the evolutionary dynamics of parasite populations are not well understood. We demonstrate that a clear picture of the evolutionary potential of parasitic organisms and their demographic and evolutionary histories can only come from understanding the role of life history and spatial structure in influencing population dynamics and epidemiological patterns. PMID:18947899

  7. Predictors of pesticide concentrations in freshwater trout - The role of life history.

    PubMed

    Scholes, Rachel C; Hageman, Kimberly J; Closs, Gerard P; Stirling, Claudine H; Reid, Malcolm R; Gabrielsson, Rasmus; Augspurger, Jason M

    2016-12-01

    Concentrations of halogenated pesticides in freshwater fish can be affected by age, size, trophic position, and exposure history. Exposure history may vary for individual fish caught at a single location due to different life histories, e.g. they may have hatched in different tributaries before migrating to a specific lake. We evaluated correlations of pesticide concentrations in freshwater brown trout (Salmo trutta) from the Clutha River, New Zealand, with potential predictors including capture site, age, length, trophic level, and life history. Life history was determined from otolith (fish ear bone) strontium isotope signatures, which vary among tributaries in the region of our study. Variability in pesticide concentrations between individual fish was not well explained by capture site, age, length, or trophic level. However, hexachlorobenzene (HCB) and chlorpyrifos concentrations were distinct in lake-based trout with different life histories. Additionally, one of the riverine life histories was associated with relatively high concentrations of total endosulfans. Linear models that included all potential predictor variables were evaluated and the resulting best models for HCB, chlorpyrifos, and total endosulfans included life history. These findings show that in cases where otolith isotope signatures vary geographically, they can be used to help explain contaminant concentration variations in fish caught from a single location. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. History of Major Depressive Disorder Prospectively Predicts Worse Quality of Life in Women with Breast Cancer

    PubMed Central

    Small, Brent J.; Minton, Susan; Andrykowski, Michael; Jacobsen, Paul B.

    2012-01-01

    Background Data are scarce about whether past history of major depressive disorder in the absence of current depression places breast cancer patients at risk for worse quality of life. Purpose The current study prospectively examined quality of life during chemotherapy in breast cancer patients with a history of resolved major depressive disorder (n=29) and no history of depression (n=144). Methods Women with Stages 0–II breast cancer were assessed prior to and at the completion of chemotherapy. Major depressive disorder was assessed via structured interview and quality of life with the SF-36. Results Patients with past major depressive disorder displayed greater declines in physical functioning relative to patients with no history of depression (p≤0.01). Conclusions Findings suggest that breast cancer patients with a history of resolved major depressive disorder are at increased risk for declines in physical functioning during chemotherapy relative to patients with no history of depression. PMID:22167580

  9. History of major depressive disorder prospectively predicts worse quality of life in women with breast cancer.

    PubMed

    Jim, Heather S L; Small, Brent J; Minton, Susan; Andrykowski, Michael; Jacobsen, Paul B

    2012-06-01

    Data are scarce about whether past history of major depressive disorder in the absence of current depression places breast cancer patients at risk for worse quality of life. The current study prospectively examined quality of life during chemotherapy in breast cancer patients with a history of resolved major depressive disorder (n = 29) and no history of depression (n = 144). Women with Stages 0-II breast cancer were assessed prior to and at the completion of chemotherapy. Major depressive disorder was assessed via structured interview and quality of life with the SF-36. Patients with past major depressive disorder displayed greater declines in physical functioning relative to patients with no history of depression (p ≤ 0.01). Findings suggest that breast cancer patients with a history of resolved major depressive disorder are at increased risk for declines in physical functioning during chemotherapy relative to patients with no history of depression.

  10. Life history strategies of fish species and biodiversity in eastern USA streams

    USGS Publications Warehouse

    Meador, Michael R.; Brown, Larry M.

    2015-01-01

    Predictive models have been used to determine fish species that occur less frequently than expected (decreasers) and those that occur more frequently than expected (increasers) in streams in the eastern U.S. Coupling life history traits with 51 decreaser and 38 increaser fish species provided the opportunity to examine potential mechanisms associated with predicted changes in fish species distributions in eastern streams. We assigned six life history traits – fecundity, longevity, maturation age, maximum total length, parental care, and spawning season duration – to each fish species. Decreaser species were significantly smaller in size and shorter-lived with reduced fecundity and shorter spawning seasons compared to increaser species. Cluster analysis of traits revealed correspondence with a life history model defining equilibrium (low fecundity, high parental care), opportunistic (early maturation, low parental care), and periodic (late maturation, high fecundity, low parental care) end-point strategies. Nearly 50 % of decreaser species were associated with an intermediate opportunistic-periodic strategy, suggesting that abiotic factors such as habitat specialization and streamflow alteration may serve as important influences on life history traits and strategies of decreaser species. In contrast, the percent of increaser species among life history strategy groups ranged from 21 to 32 %, suggesting that life history strategies of increaser species were more diverse than those of decreaser species. This study highlights the utility of linking life history theory to biodiversity to better understand mechanisms that contribute to fish species distributions in the eastern U.S.

  11. Intraspecific life history variation in contrasting habitats: Insights from an obligate symbiotic organism.

    PubMed

    Merinero, Sonia; Aragón, Gregorio; Martínez, Isabel

    2017-07-28

    Life history theory predicts that plants in unfavorable habitats for juvenile growth and survival will commence reproduction at smaller sizes and exhibit higher reproductive allocations than those in favorable habitats. The scope of life history theory will increase if these predictions apply to a broad range of organisms. Populations of organisms in contrasting habitats may experience different demographic rates. Thus, we compared the demography and life history traits of a lichen species in contrasting habitats. We compared the abundance, growth, mortality, and reproductive strategy (threshold size for reproduction and reproductive allometry) of epiphytic and saxicolous populations of the asexually reproducing lichen Lobarina scrobiculata in two oak forests in central Spain. The growth rates of saxicolous individuals were two times faster than those of epiphytic individuals. Epiphytic specimens exhibited a smaller threshold size for reproduction and a higher reproductive allocation than their saxicolous counterparts. The populations hosted by trees were two times larger than those on rocks (13,788 vs. 6629 individuals, respectively). The mortality rate did not vary between habitats. Our results demonstrate that contrasting habitats selected for differences in the demography and life history traits of a lichen species. Consistent with life history theory predictions, in the habitat with slower growth, L. scrobiculata started to reproduce at a smaller size and its reproductive allocation was higher. This study extends the scope of life history theory and improves our understanding of life history patterns and variations in overlooked taxa such as lichens. © 2017 Botanical Society of America.

  12. Dialysis: prolonging life or prolonging dying? Ethical, legal and professional considerations for end of life decision making.

    PubMed

    White, Y; Fitzpatrick, G

    2006-01-01

    There are over 7,000 people on dialysis in Australia and this is predicted to increase due to the ageing population and the high incidence of diabetes mellitus. Discontinuation of dialysis is the second most frequent cause of death in dialysis patients in Australia. Risk factors for the discontinuation of dialysis include: co-morbidities (especially diabetes mellitus) and being older. Because the decision to discontinue dialysis is a major life choice, collaborative decision making should be encouraged, and the patient needs assurances of the continuation of care and kindness, a palliative care plan, and the alleviation of suffering. Patients decide to discontinue dialysis because of an unacceptable quality of life, depression and a chronic failure to thrive. Health professionals need to support end of life decision making using an ethical decision framework. A review of current literature was undertaken and revealed a paucity of information in regard to palliation in those with end stage renal disease who had discontinued dialysis. The fear of dying, pain, suffering, and abandonment that a patient and/or their family may perceive as being associated with death may create barriers to decisions to discontinue with dialysis treatments. Therefore health care personnel should provide information with honesty to allow patients to predict their quality of life and death. Support for the patient and family during the dying period should be multi-disciplinary, with clear and timely communication between all members of the team.

  13. Movies Bring History to Life. Take It from Experience.

    ERIC Educational Resources Information Center

    Sabato, George

    1992-01-01

    Contends that feature films can heighten student interest in history. Proposes having students create film presentations based on historical topics. Includes a model research unit on Roman civilization. (CFR)

  14. Dental development and life history in living African and Asian apes.

    PubMed

    Kelley, Jay; Schwartz, Gary T

    2010-01-19

    Life-history inference is an important aim of paleoprimatology, but life histories cannot be discerned directly from the fossil record. Among extant primates, the timing of many life-history attributes is correlated with the age at emergence of the first permanent molar (M1), which can therefore serve as a means to directly compare the life histories of fossil and extant species. To date, M1 emergence ages exist for only a small fraction of extant primate species and consist primarily of data from captive individuals, which may show accelerated dental eruption compared with free-living individuals. Data on M1 emergence ages in wild great apes exist for only a single chimpanzee individual, with data for gorillas and orangutans being anecdotal. This paucity of information limits our ability to make life-history inferences using the M1 emergence ages of extinct ape and hominin species. Here we report reliable ages at M1 emergence for the orangutan, Pongo pygmaeus (4.6 y), and the gorilla, Gorilla gorilla (3.8 y), obtained from the dental histology of wild-shot individuals in museum collections. These ages and the one reported age at M1 emergence in a free-living chimpanzee of approximately 4.0 y are highly concordant with the comparative life histories of these great apes. They are also consistent with the average age at M1 emergence in relation to the timing of life-history events in modern humans, thus confirming the utility of M1 emergence ages for life-history inference and providing a basis for making reliable life-history inferences for extinct apes and hominins.

  15. The role of size-specific predation in the evolution and diversification of prey life histories.

    PubMed

    Day, Troy; Abrams, Peter A; Chase, Jonathan M

    2002-05-01

    Some of the best empirical examples of life-history evolution involve responses to predation. Nevertheless, most life-history theory dealing with responses to predation has not been formulated within an explicit dynamic food-web context. In particular, most previous theory does not explicitly consider the coupled population dynamics of the focal species and its predators and resources. Here we present a model of life-history evolution that explores the evolutionary consequences of size-specific predation on small individuals when there is a trade-off between growth and reproduction. The model explicitly describes the population dynamics of a predator, the prey of interest, and its resource. The selective forces that cause life-history evolution in the prey species emerge from the ecological interactions embodied by this model and can involve important elements of frequency dependence. Our results demonstrate that the strength of the coupling between predator and prey in the community determines many aspects of life-history evolution. If the coupling is weak (as is implicitly assumed in many previous models), differences in resource productivity have no effect on the nature of life-history evolution. A single life-history strategy is favored that minimizes the equilibrium resource density (if possible). If the coupling is strong, then higher resource productivities select for faster growth into the predation size refuge. Moreover, under strong coupling it is also possible for natural selection to favor an evolutionary diversification of life histories, possibly resulting in two coexisting species with divergent life-history strategies.

  16. Dental development and life history in living African and Asian apes

    PubMed Central

    Kelley, Jay; Schwartz, Gary T.

    2009-01-01

    Life-history inference is an important aim of paleoprimatology, but life histories cannot be discerned directly from the fossil record. Among extant primates, the timing of many life-history attributes is correlated with the age at emergence of the first permanent molar (M1), which can therefore serve as a means to directly compare the life histories of fossil and extant species. To date, M1 emergence ages exist for only a small fraction of extant primate species and consist primarily of data from captive individuals, which may show accelerated dental eruption compared with free-living individuals. Data on M1 emergence ages in wild great apes exist for only a single chimpanzee individual, with data for gorillas and orangutans being anecdotal. This paucity of information limits our ability to make life-history inferences using the M1 emergence ages of extinct ape and hominin species. Here we report reliable ages at M1 emergence for the orangutan, Pongo pygmaeus (4.6 y), and the gorilla, Gorilla gorilla (3.8 y), obtained from the dental histology of wild-shot individuals in museum collections. These ages and the one reported age at M1 emergence in a free-living chimpanzee of approximately 4.0 y are highly concordant with the comparative life histories of these great apes. They are also consistent with the average age at M1 emergence in relation to the timing of life-history events in modern humans, thus confirming the utility of M1 emergence ages for life-history inference and providing a basis for making reliable life-history inferences for extinct apes and hominins. PMID:20080537

  17. Parents and end-of-life decision-making for their child: roles and responsibilities.

    PubMed

    Sullivan, Jane; Gillam, Lynn; Monagle, Paul

    2015-09-01

    Whether parents want to be and should be the decision-maker for their child in end-of-life matters are contested clinical and ethical questions. Previous research outcomes are equivocal. A qualitative interview method was used to examine the views and experiences of 25 bereaved parents in end-of-life decision-making for their child. Data were analysed thematically. Three types of decision-making roles were identified: self-determined, guided (both involving active decision-making) and acquiescent (passive).The majority of parents had been active in the decision-making process for their child. They perceived themselves as the ultimate end-of-life decision-maker. This was perceived as part of their parental responsibility. A minority of parents did not consider that they had been an active, ultimate decision-maker. Generally, parents in the self-determined and guided groups reported no negative consequences from their decision-making involvement. Importantly, parents in the acquiescent group described their experience as difficult at the time and subsequently, although not all difficulties related directly to decision-making. Parents considered that in principle parents should be the end-of-life decision-maker for their child, but understood personal characteristics and preference could prevent some parents from taking this role. This study unequivocally supports parents' desire to fulfil the end-of-life decision-making role. It provides a nuanced understanding of parents' roles and contributes evidence for the ethical position that parents should be the end-of-life decision-makers for their child, unless not in the child's best interests. On the whole, parents want this role and can manage its consequences. Indeed, not being the end-of-life decision-maker could be detrimental to parents' well-being. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  18. The relationship between religion, illness and death in life histories of family members of children with life-threatening diseases.

    PubMed

    Bousso, Regina Szylit; Serafim, Taís de Souza; Misko, Maira Deguer

    2010-01-01

    This qualitative study aimed to get to know the relationship between the experiences of families of children with a life-threatening disease and their religion, illness and life histories. The methodological framework was based on Oral History. The data were collected through interviews and the participants were nine families from six different religions who had lived the experience of having a child with a life-threatening disease. The interviews, held with one or two family members, were transcribed, textualized and, through their analysis, the Vital Tone was elaborated, representing the moral synthesis of each narrative. Three dimensions of spirituality were related to illness and death in their life histories: a Higher Being with a healing power; Development and Maintenance of a Connection with God and Faith Encouraging Optimism. The narratives demonstrated the family's search to attribute meanings to their experiences, based on their religious beliefs.

  19. Repeated evolution of viviparity in phrynosomatid lizards constrained interspecific diversification in some life-history traits.

    PubMed

    Zúñiga-Vega, J Jaime; Fuentes-G, Jesualdo A; Ossip-Drahos, Alison G; Martins, Emília P

    2016-11-01

    In vertebrates, viviparity has evolved independently multiple times, apparently increasing morphological diversification and speciation rates as a consequence. We tested whether the evolution of viviparity has also increased diversification of life-history traits by estimating evolutionary rates of lizards from the North American family Phrynosomatidae. Using modern phylogenetic comparative methods, we compared these rates between oviparous and viviparous species, and found no support for this hypothesis. Instead, we found higher evolutionary rates for oviparous species in some life-history traits. Our results suggest that the evolution of viviparity may have constrained rather than facilitated evolution of life histories. © 2016 The Author(s).

  20. Armitage Lecture 2011: the design and analysis of life history studies.

    PubMed

    Lawless, Jerald F

    2013-06-15

    Life history studies collect information on events and other outcomes during people's lifetimes. For example, these may be related to childhood development, education, fertility, health, or employment. Such longitudinal studies have constraints on the selection of study members, the duration and frequency of follow-up, and the accuracy and completeness of information obtained. These constraints, along with factors associated with the definition and measurement of certain outcomes, affect our ability to understand, model, and analyze life history processes. My objective here is to discuss and illustrate some issues associated with the design and analysis of life history studies.

  1. Fetal origins of developmental plasticity: animal models of induced life history variation.

    PubMed

    Horton, Teresa H

    2005-01-01

    The interaction of the genetic program with the environment shapes the development of an individual. Accumulating data from animal models indicate that prenatal and early-postnatal events (collectively called "early-life events") can initiate long-term changes in the expression of the genetic program which persist, or may only become apparent, much later in the individual's life. Researchers working with humans or animal models of human diseases often view the effects of early-life events through the lens of pathology, with a focus on whether the events increase the risk for a particular disease. Alternatively, comparative biologists often view the effects of early-life events through the lens of evolution and adaptation by natural selection; they investigate the processes by which environmental conditions present early in life may prompt the adoption of different developmental pathways leading to alternative life histories. Examples of both approaches are presented in this article. This article reviews the concepts of phenotypic plasticity, natural selection, and evidence from animal models that early-life events can program the activity of the neuroendocrine system, at times altering life history patterns in an adaptive manner. Data from seasonally breeding rodents are used to illustrate the use of maternally derived information to alter the life history of young. In several species, the maternal system transfers photoperiodic information to the young in utero. This maternally derived information alters the response of young to photoperiods encountered later and life, producing seasonally distinct life histories. (c) 2004 Wiley-Liss, Inc.

  2. Source, Method, and Surmise: Quality of Life in History

    ERIC Educational Resources Information Center

    Jordan, Thomas E.

    2009-01-01

    The purpose of the essay is to demonstrate that study of quality of life can explore eras before our own. There are caches of social data as early as the seventeenth century, and there were people who attempted to formulate social circumstances close to today's concepts of quality of life. Data from England and Ireland are presented and analyzed.

  3. Source, Method, and Surmise: Quality of Life in History

    ERIC Educational Resources Information Center

    Jordan, Thomas E.

    2009-01-01

    The purpose of the essay is to demonstrate that study of quality of life can explore eras before our own. There are caches of social data as early as the seventeenth century, and there were people who attempted to formulate social circumstances close to today's concepts of quality of life. Data from England and Ireland are presented and analyzed.

  4. An Exploratory Study of Life-Change Events, Social Support and Pregnancy Decisions in Adolescents.

    ERIC Educational Resources Information Center

    Carlson, Mary L.; And Others

    1984-01-01

    Examined influences on decisions regarding pregnancy outcome in 43 adolescents who completed the Adolescent Life Change Event Questionnaire and the Social Support Questionnaire. Those continuing the pregnancy (N=30) had higher life event change scores, lower social support scores, and more personal and family problems. (JAC)

  5. Intergenerational Differences and Similarities in Life-Sustaining Treatment Attitudes and Decision Factors.

    ERIC Educational Resources Information Center

    Mills, Terry L.; Wilmoth, Janet M.

    2002-01-01

    A cross-sectional sample of three-generation families was used to evaluate life-sustaining medical treatment attitudes and decision factors. Results show that the older generation perceived mental capacity, family burden, and pain as most important considerations. Among the middle generation the type of life-sustaining treatment was important. The…

  6. Palliative and end-of-life decision-making in dementia care.

    PubMed

    Mitchell, Gary

    2015-11-01

    This paper will highlight some of the pertinent issues associated with palliative and end-of-life decision-making in relation to dementia. To achieve this, the author will consider why there is disparity in relation to shared decision-making practices across non-malignant disease through exploration of models of disease trajectories. The author will then go on to highlight how people living with dementia, a non-malignant disease, have a human right to receive palliative care and be an active agent in the shared decision-making process about their future and care preferences. The challenges of shared decision-making in dementia care will be discussed along with some implications for nursing practice. The aim of this paper is to provide nurses, practising across all settings, with an overview of the fundamental importance of timely palliative and end-of-life shared decision-making in dementia care.

  7. Variation in end-of-life decision making between critical care consultants.

    PubMed

    Poulton, B; Ridley, S; Mackenzie-Ross, R; Rizvi, S

    2005-11-01

    Considerable variation in end-of-life decision making is reported between intensive care units in the United Kingdom, possibly because of differences in casemix. Senior medical staff within any one unit should, however, be consistent in such decision making. We reviewed the medical records for a 4-year period to establish if there was consistency in our own unit. This revealed considerable variation in the apparent willingness of consultants to make end-of-life decisions, emphasising the subjective nature of these decisions. Personality typing (Myers-Briggs Type Indicator) of consultants revealed that those who had made more than the expected number of decisions had scores towards the judging end of the judging/perceiving domain.

  8. Modafinil alters decision making based on feedback history - a randomized placebo-controlled double blind study in humans.

    PubMed

    Bellebaum, Christian; Kuchinke, Lars; Roser, Patrik

    2017-02-01

    Modafinil is becoming increasingly popular as a cognitive enhancer. Research on the effects of modafinil on cognitive function have yielded mixed results, with negative findings for simple memory and attention tasks and enhancing effects for more complex tasks. In the present study we examined whether modafinil, due to its known effect on the dopamine level in the striatum, alters feedback-related choice behaviour. We applied a task that separately tests the choice of previously rewarded behaviours (approach) and avoidance of previously punished behaviours. 18 participants received a single dose of 200 mg modafinil. Their performance was compared to a group of 22 participants who received placebo in a double-blind design. Modafinil but not placebo induced a significant bias towards approach behaviour as compared to the frequency of avoidance behaviour. General attention, overall feedback-based acquisition of choice behaviour and reaction times in high vs low conflict choices were not significantly affected by modafinil. This finding suggests that modafinil has a specific effect on dopamine-mediated choice behaviour based on the history of feedback, while a contribution of noradrenaline is also conceivable. The described change in decision making cannot be considered as cognitive enhancement, but might rather have detrimental effects on decisions in everyday life.

  9. [End-of life decisions in intensive care units. Influence of patient wishes on therapeutic decision making].

    PubMed

    Riessen, R; Bantlin, C; Wiesing, U; Haap, M

    2013-06-01

    Among the ethical principles in medicine, respect for patient autonomy has gained the highest revaluation in recent decades. In Germany this was fostered by new legal regulations which came into effect in 2009 and clarified issues regarding end-of-life (EOL) decisions. In this study the influence of direct or mediated wishes of patient wills on EOL decisions in a medical intensive care unit (ICU) were investigated. A retrospective analysis of all patients who died in the years 2009-2010 while being treated in the medical ICU of a large German university hospital was carried out. During the observation period 3,401 patients were treated in the ICU of whom 19 % (n=658) died in hospital. Of the 658 patients who died 126 (19 %) had received unlimited therapy, life support was withheld in 241 patients (37 %) and life support was withdrawn in 245 patients (37 %). In 46 patients (7 %) palliative care was instituted from the beginning of the ICU stay. In 104 cases (16 %) the patients themselves made the EOL decision and in 78 cases (12 %) an advance directive was given. A legal healthcare proxy was designated in 8 %. In 541 cases (82 %) the relatives were involved in the EOL decisions. No serious or unsolvable conflicts with relatives were experienced. Involvement of a court of law was not necessary in any of the cases. In a high percentage of the patients (81 %) who died during the course of intensive care treatment EOL policies were in place. The patients or their relatives were almost always involved in the decision making process. The current German law is in concordance with the established EOL practice in this intensive care unit.

  10. Life Stress and Family History for Depression: The Moderating Role of Past Depressive Episodes

    PubMed Central

    Monroe, Scott M.; Slavich, George M.; Gotlib, Ian H.

    2014-01-01

    Three of the most consistently reported and powerful predictors of depression are a recent major life event, a positive family history for depression, and a personal history of past depressive episodes. Little research, however, has evaluated the inter-relations among these predictors in depressed samples. Such information is descriptively valuable and potentially etiologically informative. In the present article we summarize the existing literature and test four predictions in a sample of 62 clinically depressed individuals: (1) participants who experienced a major life event prior to onset would be less likely than participants who did not experience a major life event to have a positive family history for depression; (2) participants with a recent major life event would have fewer lifetime episodes of depression than would participants without; (3) participants with a positive family history for depression would have more lifetime episodes of depression than would participants with a negative family history for depression; and (4) we would obtain a 3-way interaction in which participants with a positive family history and without a major life event would have the most lifetime episodes, whereas participants with a negative family history and a major life event would have the fewest lifetime episodes. The first three predictions were confirmed, and the fourth prediction partially confirmed. These novel findings begin to elucidate the complex relations among these three prominent risk factors for depression, and point to avenues of research that may help illuminate the origins of depressive episodes. PMID:24308926

  11. Life stress and family history for depression: the moderating role of past depressive episodes.

    PubMed

    Monroe, Scott M; Slavich, George M; Gotlib, Ian H

    2014-02-01

    Three of the most consistently reported and powerful predictors of depression are a recent major life event, a positive family history for depression, and a personal history of past depressive episodes. Little research, however, has evaluated the inter-relations among these predictors in depressed samples. Such information is descriptively valuable and potentially etiologically informative. In the present article we summarize the existing literature and test four predictions in a sample of 62 clinically depressed individuals: (1) participants who experienced a major life event prior to onset would be less likely than participants who did not experience a major life event to have a positive family history for depression; (2) participants with a recent major life event would have fewer lifetime episodes of depression than would participants without; (3) participants with a positive family history for depression would have more lifetime episodes of depression than would participants with a negative family history for depression; and (4) we would obtain a 3-way interaction in which participants with a positive family history and without a major life event would have the most lifetime episodes, whereas participants with a negative family history and a major life event would have the fewest lifetime episodes. The first three predictions were confirmed, and the fourth prediction partially confirmed. These novel findings begin to elucidate the complex relations among these three prominent risk factors for depression, and point to avenues of research that may help illuminate the origins of depressive episodes.

  12. Bone morphologies and histories: Life course approaches in bioarchaeology.

    PubMed

    Agarwal, Sabrina C

    2016-01-01

    The duality of the skeleton as both a biological and cultural entity has formed the theoretical basis of bioarchaeology. In recent years bioarchaeological studies have stretched the early biocultural concept with the adoption of life course approaches in their study design and analyses, making a significant contribution to how we think about the role of postnatal plasticity. Life course theory is a conceptual framework used in several scientific fields of biology and the social sciences. Studies that emphasize life course approaches in the examination of bone morphology in the past are united in their interrogation of human life as a result of interrelated and cumulative events over not only the timeframe of individuals, but also over generations at the community level. This article provides an overview of the theoretical constructs that utilize the life course concept, and a discussion of the different ways these theories have been applied to thinking about trajectories of bone morphology in the past, specifically highlighting key recent studies that have used life course approaches to understand the influence of growth, stress, diet, activity, and aging on the skeleton. The goal of this article is to demonstrate the scope of contemporary bioarchaeological studies that illuminate the importance of environmental and behavioral influence on bone morphology. Understanding how trajectories of bone growth and morphology can be altered and shaped over the life course is critical not only for bioarchaeologists, but also researchers studying bone morphology in living nonhuman primates and fossil primate skeletons. © 2016 Wiley Periodicals, Inc.

  13. Trends in medical end-of-life decision making in Flanders, Belgium 1998-2001-2007.

    PubMed

    Chambaere, Kenneth; Bilsen, Johan; Cohen, Joachim; Onwuteaka-Philipsen, Bregje D; Mortier, Freddy; Deliens, Luc

    2011-01-01

    In 2002, Belgium saw the enactment of 3 laws concerning euthanasia, palliative care, and patient rights that are likely to affect end-of-life decision making. This report examines trends in the occurrence and decision-making process of end-of-life practices in different patient groups since these legal changes. A large-scale retrospective survey in Flanders, Belgium, previously conducted in 1998 and 2001, was repeated in 2007. Questionnaires regarding end-of-life practices and the preceding decision-making process were mailed to physicians who certified a representative sample (N = 6927) of death certificates. The 2007 response rate was 58.4%. In patient groups in which the prevalence of life-ending drug use without explicit patient request has dropped, performance of euthanasia and assisted suicide has increased. The consistent increase in intensified pain and symptom alleviation was found in all patient groups except cancer patients. In 2007, competent patients were slightly more often involved in the discussion of end-of-life practices than in previous years. Over the years, involvement of the patient in decision making was consistently more likely among younger patients, cancer patients, and those dying at home. Physicians consulted their colleagues more often than in previous years for euthanasia and nontreatment decisions. The euthanasia law and emerging palliative care culture have substantially affected the occurrence and decision making for end-of-life practices in Belgium. Efforts are still needed to encourage shared end-of-life decision making, as some patients would benefit from advance care planning.

  14. An evaluation of two decision-making scales for children with life-limiting illnesses

    PubMed Central

    Knapp, C; Huang, IC; Madden, V; Vadaparampil, S; Quinn, G; Shenkman, E

    2013-01-01

    Purpose Annually, about 500,000 children are coping with life-limiting illnesses. Many of these children could benefit from pediatric palliative care which provides supportive services. These services can also aid parents in decision making. In order to measure the effect of pediatric palliative care programs on decision making, a valid and reliable tool must be identified. This study aims to validate the psychometric properties of the Decisional Conflict Scale (DCS) and the COMRADE instruments for children with life-limiting illnesses. Methods Analyses were conducted using survey data collected from 266 parents whose Medicaid enrolled children have life-limiting illnesses. Results Results of the analyses suggest that the DCS has better psychometric properties for measuring decision making within the population of children with life-limiting illnesses than the COMRADE. Conclusion Pediatric palliative care programs should use the DCS to measure the effectiveness of services aimed at supporting families with high levels of decisional conflict. PMID:19346274

  15. Where Wolves Kill Moose: The Influence of Prey Life History Dynamics on the Landscape Ecology of Predation

    PubMed Central

    Montgomery, Robert A.; Vucetich, John A.; Roloff, Gary J.; Bump, Joseph K.; Peterson, Rolf O.

    2014-01-01

    The landscape ecology of predation is well studied and known to be influenced by habitat heterogeneity. Little attention has been given to how the influence of habitat heterogeneity on the landscape ecology of predation might be modulated by life history dynamics of prey in mammalian systems. We demonstrate how life history dynamics of moose (Alces alces) contribute to landscape patterns in predation by wolves (Canis lupus) in Isle Royale National Park, Lake Superior, USA. We use pattern analysis and kernel density estimates of moose kill sites to demonstrate that moose in senescent condition and moose in prime condition tend to be wolf-killed in different regions of Isle Royale in winter. Predation on senescent moose was clustered in one kill zone in the northeast portion of the island, whereas predation on prime moose was clustered in 13 separate kill zones distributed throughout the full extent of the island. Moreover, the probability of kill occurrence for senescent moose, in comparison to prime moose, increased in high elevation habitat with patches of dense coniferous trees. These differences can be attributed, at least in part, to senescent moose being more vulnerable to predation and making different risk-sensitive habitat decisions than prime moose. Landscape patterns emerging from prey life history dynamics and habitat heterogeneity have been observed in the predation ecology of fish and insects, but this is the first mammalian system for which such observations have been made. PMID:24622241

  16. Where wolves kill moose: the influence of prey life history dynamics on the landscape ecology of predation.

    PubMed

    Montgomery, Robert A; Vucetich, John A; Roloff, Gary J; Bump, Joseph K; Peterson, Rolf O

    2014-01-01

    The landscape ecology of predation is well studied and known to be influenced by habitat heterogeneity. Little attention has been given to how the influence of habitat heterogeneity on the landscape ecology of predation might be modulated by life history dynamics of prey in mammalian systems. We demonstrate how life history dynamics of moose (Alces alces) contribute to landscape patterns in predation by wolves (Canis lupus) in Isle Royale National Park, Lake Superior, USA. We use pattern analysis and kernel density estimates of moose kill sites to demonstrate that moose in senescent condition and moose in prime condition tend to be wolf-killed in different regions of Isle Royale in winter. Predation on senescent moose was clustered in one kill zone in the northeast portion of the island, whereas predation on prime moose was clustered in 13 separate kill zones distributed throughout the full extent of the island. Moreover, the probability of kill occurrence for senescent moose, in comparison to prime moose, increased in high elevation habitat with patches of dense coniferous trees. These differences can be attributed, at least in part, to senescent moose being more vulnerable to predation and making different risk-sensitive habitat decisions than prime moose. Landscape patterns emerging from prey life history dynamics and habitat heterogeneity have been observed in the predation ecology of fish and insects, but this is the first mammalian system for which such observations have been made.

  17. A decisive step toward the origin of life.

    PubMed

    Paleos, C M

    2015-09-01

    Several hypotheses exist regarding how life emerged from the abiotic world, the most popular of which is the 'RNA World' hypothesis. Recent advances describe nonenzymatic polymerization of mononucleotides in a phospholipid liquid crystalline matrix, suggesting that a 'Lipid World' might have preceded the RNA World.

  18. End-of-life care ethical decision-making: Shiite scholars' views.

    PubMed

    Mobasher, Mina; Aramesh, Kiarash; Zahedi, Farzaneh; Nakhaee, Nouzar; Tahmasebi, Mamak; Larijani, Bagher

    2014-01-01

    Recent advances in life-sustaining treatments and technologies, have given rise to newly-emerged, critical and sometimes, controversial questions regarding different aspects of end-of-life decision-making and care. Since religious values are among the most influential factors in these decisions, the present study aimed to examine the Islamic scholars' views on end-of-life care. A structured interview based on six main questions on ethical decision-making in end-of-life care was conducted with eight Shiite experts in Islamic studies, and was analyzed through deductive content analysis. Analysis revealed certain points in Islamic views on the definition of death and the persons making decisions about end-of-life care. According to the participants, in addition to conventional criteria ('urf) such as absence of heartbeat and respiration, the irreversible cessation of human voluntary acts (as a sign that the soul has control over the body and the faculty of thinking) are considered to be the criteria in establishing death. The participants also recognized physicians as the main authorities in verifying signs of death. Furthermore, it was emphasized that life preservation and continuation of care must be sensible, and the patient can request not to have death-prolonging procedures started or continued. In the view of participants, patient's autonomy cannot be the sole basis for all measures, but Islamic ethical and jurisprudential principles should be relied upon to make correct and sensible decisions whether to continue or stop terminal patients' care. Final decisions should be made by a team of experts, and physicians must be at the center of such a team. Finally, we suggest that a guideline in keeping with Islamic norms on human life and death, purpose of life, God's will, boundaries of man's authority, and the physician's ethical duties and obligations should be developed.

  19. End-of-life care ethical decision-making: Shiite scholars’ views

    PubMed Central

    Mobasher, Mina; Aramesh, Kiarash; Zahedi, Farzaneh; Nakhaee, Nouzar; Tahmasebi, Mamak; Larijani, Bagher

    2014-01-01

    Recent advances in life-sustaining treatments and technologies, have given rise to newly-emerged, critical and sometimes, controversial questions regarding different aspects of end-of-life decision-making and care. Since religious values are among the most influential factors in these decisions, the present study aimed to examine the Islamic scholars’ views on end-of-life care. A structured interview based on six main questions on ethical decision-making in end-of-life care was conducted with eight Shiite experts in Islamic studies, and was analyzed through deductive content analysis. Analysis revealed certain points in Islamic views on the definition of death and the persons making decisions about end-of-life care. According to the participants, in addition to conventional criteria (‘urf) such as absence of heartbeat and respiration, the irreversible cessation of human voluntary acts (as a sign that the soul has control over the body and the faculty of thinking) are considered to be the criteria in establishing death. The participants also recognized physicians as the main authorities in verifying signs of death. Furthermore, it was emphasized that life preservation and continuation of care must be sensible, and the patient can request not to have death-prolonging procedures started or continued. In the view of participants, patient’s autonomy cannot be the sole basis for all measures, but Islamic ethical and jurisprudential principles should be relied upon to make correct and sensible decisions whether to continue or stop terminal patients’ care. Final decisions should be made by a team of experts, and physicians must be at the center of such a team. Finally, we suggest that a guideline in keeping with Islamic norms on human life and death, purpose of life, God’s will, boundaries of man’s authority, and the physician’s ethical duties and obligations should be developed. PMID:25512823

  20. Current research findings on end-of-life decision making among racially or ethnically diverse groups.

    PubMed

    Kwak, Jung; Haley, William E

    2005-10-01

    We reviewed the research literature on racial or ethnic diversity and end-of-life decision making in order to identify key findings and provide recommendations for future research. We identified 33 empirical studies in which race or ethnicity was investigated as either a variable predicting treatment preferences or choices, where racial or ethnic groups were compared in their end-of-life decisions, or where the end-of-life decision making of a single minority group was studied in depth. We conducted a narrative review and identified four topical domains of study: advance directives; life support; disclosure and communication of diagnosis, prognosis, and preferences; and designation of primary decision makers. Non-White racial or ethnic groups generally lacked knowledge of advance directives and were less likely than Whites to support advance directives. African Americans were consistently found to prefer the use of life support; Asians and Hispanics were more likely to prefer family-centered decision making than other racial or ethnic groups. Variations within groups existed and were related to cultural values, demographic characteristics, level of acculturation, and knowledge of end-of-life treatment options. Common methodological limitations of these studies were lack of theoretical framework, use of cross-sectional designs, convenience samples, and self-developed measurement scales. Although the studies are limited by methodological concerns, identified differences in end-of-life decision-making preference and practice suggest that clinical care and policy should recognize the variety of values and preferences found among diverse racial or ethnic groups. Future research priorities are described to better inform clinicians and policy makers about ways to allow for more culturally sensitive approaches to end-of-life care.

  1. Hibernation is associated with increased survival and the evolution of slow life histories among mammals.

    PubMed

    Turbill, Christopher; Bieber, Claudia; Ruf, Thomas

    2011-11-22

    Survival probability is predicted to underlie the evolution of life histories along a slow-fast continuum. Hibernation allows a diverse range of small mammals to exhibit seasonal dormancy, which might increase survival and consequently be associated with relatively slow life histories. We used phylogenetically informed GLS models to test for an effect of hibernation on seasonal and annual survival, and on key attributes of life histories among mammals. Monthly survival was in most cases higher during hibernation compared with the active season, probably because inactivity minimizes predation. Hibernators also have approximately 15 per cent higher annual survival than similar sized non-hibernating species. As predicted, we found an effect of hibernation on the relationships between life history attributes and body mass: small hibernating mammals generally have longer maximum life spans (50% greater for a 50 g species), reproduce at slower rates, mature at older ages and have longer generation times compared with similar-sized non-hibernators. In accordance with evolutionary theories, however, hibernating species do not have longer life spans than non-hibernators with similar survival rates, nor do they have lower reproductive rates than non-hibernators with similar maximum life spans. Thus, our combined results suggest that (i) hibernation is associated with high rates of overwinter and annual survival, and (ii) an increase in survival in hibernating species is linked with the coevolution of traits indicative of relatively slow life histories.

  2. Hibernation is associated with increased survival and the evolution of slow life histories among mammals

    PubMed Central

    Turbill, Christopher; Bieber, Claudia; Ruf, Thomas

    2011-01-01

    Survival probability is predicted to underlie the evolution of life histories along a slow–fast continuum. Hibernation allows a diverse range of small mammals to exhibit seasonal dormancy, which might increase survival and consequently be associated with relatively slow life histories. We used phylogenetically informed GLS models to test for an effect of hibernation on seasonal and annual survival, and on key attributes of life histories among mammals. Monthly survival was in most cases higher during hibernation compared with the active season, probably because inactivity minimizes predation. Hibernators also have approximately 15 per cent higher annual survival than similar sized non-hibernating species. As predicted, we found an effect of hibernation on the relationships between life history attributes and body mass: small hibernating mammals generally have longer maximum life spans (50% greater for a 50 g species), reproduce at slower rates, mature at older ages and have longer generation times compared with similar-sized non-hibernators. In accordance with evolutionary theories, however, hibernating species do not have longer life spans than non-hibernators with similar survival rates, nor do they have lower reproductive rates than non-hibernators with similar maximum life spans. Thus, our combined results suggest that (i) hibernation is associated with high rates of overwinter and annual survival, and (ii) an increase in survival in hibernating species is linked with the coevolution of traits indicative of relatively slow life histories. PMID:21450735

  3. Transcriptomic and macroevolutionary evidence for phenotypic uncoupling between frog life history phases

    PubMed Central

    Wollenberg Valero, Katharina C.; Garcia-Porta, Joan; Rodríguez, Ariel; Arias, Mónica; Shah, Abhijeet; Randrianiaina, Roger Daniel; Brown, Jason L.; Glaw, Frank; Amat, Felix; Künzel, Sven; Metzler, Dirk; Isokpehi, Raphael D.; Vences, Miguel

    2017-01-01

    Anuran amphibians undergo major morphological transitions during development, but the contribution of their markedly different life-history phases to macroevolution has rarely been analysed. Here we generate testable predictions for coupling versus uncoupling of phenotypic evolution of tadpole and adult life-history phases, and for the underlying expression of genes related to morphological feature formation. We test these predictions by combining evidence from gene expression in two distantly related frogs, Xenopus laevis and Mantidactylus betsileanus, with patterns of morphological evolution in the entire radiation of Madagascan mantellid frogs. Genes linked to morphological structure formation are expressed in a highly phase-specific pattern, suggesting uncoupling of phenotypic evolution across life-history phases. This gene expression pattern agrees with uncoupled rates of trait evolution among life-history phases in the mantellids, which we show to have undergone an adaptive radiation. Our results validate a prevalence of uncoupling in the evolution of tadpole and adult phenotypes of frogs. PMID:28504275

  4. Transcriptomic and macroevolutionary evidence for phenotypic uncoupling between frog life history phases.

    PubMed

    Wollenberg Valero, Katharina C; Garcia-Porta, Joan; Rodríguez, Ariel; Arias, Mónica; Shah, Abhijeet; Randrianiaina, Roger Daniel; Brown, Jason L; Glaw, Frank; Amat, Felix; Künzel, Sven; Metzler, Dirk; Isokpehi, Raphael D; Vences, Miguel

    2017-05-15

    Anuran amphibians undergo major morphological transitions during development, but the contribution of their markedly different life-history phases to macroevolution has rarely been analysed. Here we generate testable predictions for coupling versus uncoupling of phenotypic evolution of tadpole and adult life-history phases, and for the underlying expression of genes related to morphological feature formation. We test these predictions by combining evidence from gene expression in two distantly related frogs, Xenopus laevis and Mantidactylus betsileanus, with patterns of morphological evolution in the entire radiation of Madagascan mantellid frogs. Genes linked to morphological structure formation are expressed in a highly phase-specific pattern, suggesting uncoupling of phenotypic evolution across life-history phases. This gene expression pattern agrees with uncoupled rates of trait evolution among life-history phases in the mantellids, which we show to have undergone an adaptive radiation. Our results validate a prevalence of uncoupling in the evolution of tadpole and adult phenotypes of frogs.

  5. Evaluating life-history strategies of reef corals from species traits.

    PubMed

    Darling, Emily S; Alvarez-Filip, Lorenzo; Oliver, Thomas A; McClanahan, Timothy R; Côté, Isabelle M; Bellwood, David

    2012-12-01

    Classifying the biological traits of organisms can test conceptual frameworks of life-history strategies and allow for predictions of how different species may respond to environmental disturbances. We apply a trait-based classification approach to a complex and threatened group of species, scleractinian corals. Using hierarchical clustering and random forests analyses, we identify up to four life-history strategies that appear globally consistent across 143 species of reef corals: competitive, weedy, stress-tolerant and generalist taxa, which are primarily separated by colony morphology, growth rate and reproductive mode. Documented shifts towards stress-tolerant, generalist and weedy species in coral reef communities are consistent with the expected responses of these life-history strategies. Our quantitative trait-based approach to classifying life-history strategies is objective, applicable to any taxa and a powerful tool that can be used to evaluate theories of community ecology and predict the impact of environmental and anthropogenic stressors on species assemblages.

  6. The uses of life: A history of biotechnology

    SciTech Connect

    Bud, R.

    1993-01-01

    This book is largely a history of what biotechnology and related terms meant many years ago. The book focuses on those aspects of biotechnology that could reasonably be considered to have arisen out of chemical engineering. Included in the book is an extensive description of a Swedish program developed by Car Heden in the 1960s to study engineering aspects of microbiology.

  7. Adventist Philosophy Applied to Campus Life: History of an Experience.

    ERIC Educational Resources Information Center

    Castillo, Ismael; Korniejczuk, Raquel

    2001-01-01

    Describes the general curriculum, common to all programs, at the University of Montemorelos, a Seventh-day Adventist institution, also examining the history of the curriculum design process and the implementation process. The university's institutional curriculum is congruent with the convictions and beliefs it holds regarding higher education…

  8. Older Adults’ Preferences for Independent or Delegated End-of-Life Medical Decision-Making

    PubMed Central

    Moorman, Sara M.

    2011-01-01

    Objectives This study assesses the proportions of participants who prefer independent or delegated medical decision-making at end-of-life, and examines the relationships of personal beliefs, affiliative beliefs, and end-of-life planning behaviors to decision-making preference. Methods Data are drawn from the Wisconsin Longitudinal Study, a sample of nearly 4,500 healthy white Midwestern high school graduates in their mid-60s. Results Four-fifths of participants wanted to make decisions independently. Valuing independence, being less avoidant of thoughts of death, and valuing quality of life over length of life had strong associations with a preference for independent decision-making. Those concerned about burdening a caregiver wanted to make independent decisions. Persons who both executed a living will and appointed a durable power of attorney for health care preferred independent decision-making. Discussion Older adults cite personal and affiliative beliefs, not lack of autonomy, as reasons for their choice to decide independently or delegate. PMID:20947875

  9. Species Profiles. Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (Pacific Southwest). Dungeness Crab

    DTIC Science & Technology

    1989-12-01

    AD-A224 837 Biological Report 82(11.121) TR EL-82-4 December 1989 13W i~L COPXYO C hE PYDTIC Species Profiles: Life Histories and ELECTE... Biological Report 82 (11.121) TR EL-82-4 December 1989 Species Profiles: Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates...importance. The profiles are designed to provide coastal managers, engineers, and biologists with a brief comprehensive sketch of the biological

  10. Hormonal correlates of male life history stages in wild white-faced capuchin monkeys (Cebus capucinus)

    PubMed Central

    Jack, Katharine M.; Schoof, Valérie A.M.; Sheller, Claire R.; Rich, Catherine I.; Klingelhofer, Peter P.; Ziegler, Toni E.; Fedigan, Linda

    2014-01-01

    Much attention has been paid to hormonal variation in relation to male dominance status and reproductive seasonality, but we know relatively little about how hormones vary across life history stages. Here we examine fecal testosterone (fT), dihydrotestosterone (fDHT), and glucocorticoid (fGC) profiles across male life history stages in wild white-faced capuchins (Cebus capucinus). Study subjects included 37 males residing in three habituated social groups in the Área de Conservacíon Guanacaste, Costa Rica. Male life history stages included infant (0 to <12 months; N = 3), early juvenile (1 to <3 years; N = 10), late juvenile (3 to <6 years; N = 9), subadult (6 to <10 years; N = 8), subordinate adult (≥10 years; N = 3), and alpha adult (≥ 10 years; N = 4, including one recently deposed alpha). Life history stage was a significant predictor of fT; levels were low throughout the infant and juvenile phases, doubled in subadult and subordinate adults, and were highest for alpha males. Life history stage was not a significant predictor of fDHT, fDHT:fT, or fGC levels. Puberty in white-faced capuchins appears to begin in earnest during the subadult male phase, indicated by the first significant rise in fT. Given their high fT levels and exaggerated secondary sexual characteristics, we argue that alpha adult males represent a distinctive life history stage not experienced by all male capuchins. This study is the first to physiologically validate observable male life history stages using patterns of hormone excretion in wild Neotropical primates, with evidence for a strong association between fT levels and life history stage. PMID:24184868

  11. Hormonal correlates of male life history stages in wild white-faced capuchin monkeys (Cebus capucinus).

    PubMed

    Jack, Katharine M; Schoof, Valérie A M; Sheller, Claire R; Rich, Catherine I; Klingelhofer, Peter P; Ziegler, Toni E; Fedigan, Linda

    2014-01-01

    Much attention has been paid to hormonal variation in relation to male dominance status and reproductive seasonality, but we know relatively little about how hormones vary across life history stages. Here we examine fecal testosterone (fT), dihydrotestosterone (fDHT), and glucocorticoid (fGC) profiles across male life history stages in wild white-faced capuchins (Cebus capucinus). Study subjects included 37 males residing in three habituated social groups in the Área de Conservacíon Guanacaste, Costa Rica. Male life history stages included infant (0 to <12months; N=3), early juvenile (1 to <3years; N=10), late juvenile (3 to <6years; N=9), subadult (6 to <10years; N=8), subordinate adult (⩾10years; N=3), and alpha adult (⩾10years; N=4, including one recently deposed alpha). Life history stage was a significant predictor of fT; levels were low throughout the infant and juvenile phases, doubled in subadult and subordinate adults, and were highest for alpha males. Life history stage was not a significant predictor of fDHT, fDHT:fT, or fGC levels. Puberty in white-faced capuchins appears to begin in earnest during the subadult male phase, indicated by the first significant rise in fT. Given their high fT levels and exaggerated secondary sexual characteristics, we argue that alpha adult males represent a distinctive life history stage not experienced by all male capuchins. This study is the first to physiologically validate observable male life history stages using patterns of hormone excretion in wild Neotropical primates, with evidence for a strong association between fT levels and life history stage.

  12. Explanations for attractiveness-related positive biases in an evolutionary perspective of life history theory.

    PubMed

    Chen, Bin-Bin

    2017-01-01

    The mating-related evolutionary explanation that Maestripieri et al. offer does not apply to (1) infants' positive biases toward attractive individuals and (2) adults' positive biases toward attractive infants and children. They are best understood when integrated into an evolutionary life history framework. I argue that the life history of positive biases toward attractive individuals is driven by fundamental trade-offs made throughout development.

  13. Does life history predict risk-taking behavior of wintering dabbling ducks?

    USGS Publications Warehouse

    Ackerman, Joshua T.; Eadie, J.M.; Moore, T.G.

    2006-01-01

    Life-history theory predicts that longer-lived, less fecund species should take fewer risks when exposed to predation than shorter-lived, more fecund species. We tested this prediction for seven species of dabbling ducks (Anas) by measuring the approach behavior (behavior of ducks when approaching potential landing sites) of 1099 duck flocks during 37 hunting trials and 491 flocks during 13 trials conducted immediately after the 1999-2000 waterfowl hunting season in California, USA. We also experimentally manipulated the attractiveness of the study site by using two decoy treatments: (1) traditional, stationary decoys only, and (2) traditional decoys in conjunction with a mechanical spinning-wing decoy. Approach behavior of ducks was strongly correlated with their life history. Minimum approach distance was negatively correlated with reproductive output during each decoy treatment and trial type. Similarly, the proportion of flocks taking risk (approaching landing sites to within 45 m) was positively correlated with reproductive output. We found similar patterns of approach behavior in relation to other life-history parameters (i.e., adult female body mass and annual adult female survival rate). Thus, species characterized by a slower life-history strategy (e.g., Northern Pintail [A. acuta]) were more risk-averse than species with a faster life-history strategy (e.g., Cinnamon Teal [A. cyanoptera]). Furthermore, although we were able to reduce risk-averseness using the spinning-wing decoy, we were unable to override the influence of life history on risk-taking behavior. Alternative explanations did not account for the observed correlation between approach behavior and life-history parameters. These results suggest that life history influences the risk-taking behavior of dabbling ducks and provide an explanation for the differential vulnerability of waterfowl to harvest. ?? The Cooper Ornithological Society 2006.

  14. Species Profiles. Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (Pacific Northwest). Lingcod

    DTIC Science & Technology

    1989-12-01

    Res. Board Can. Kabata, F. 1973. The species of 20(2):257-264. Lepeophiheirus ( Copepoda : Caligidae) from fishes in British Columbia. J. Fish. Res...AD-A224 839 Biological Report 82(11.119) TR EL-82-4 December 1989 OTC FiLE COPY Species Profiles: Life Histories and Environmental Requirements of...1989 Species Profiles: Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (Pacific Northwest) LINGCOD by William N

  15. Species Profiles: life histories and environmental requirements of coastal fishes and invertebrates (North Atlantic)

    SciTech Connect

    Not Available

    1984-01-01

    Species Profiles are summaries of the life histories and environmental requirements of selected coastal fishes and invertebrates of commercial, recreational, or ecological significance. The Profiles will be used to relate life history and environmental requirements of species to coastal numerical water quality models and to assist in evaluating the environmental impacts of altering estuarine habitats. For this program the marine coastline of the continental United States was divided into the following seven biogeographic regions.

  16. Family members' informal roles in end-of-life decision making in adult intensive care units.

    PubMed

    Quinn, Jill R; Schmitt, Madeline; Baggs, Judith Gedney; Norton, Sally A; Dombeck, Mary T; Sellers, Craig R

    2012-01-01

    To support the process of effective family decision making, it is important to recognize and understand informal roles that various family members may play in the end-of-life decision-making process. To describe some informal roles consistently enacted by family members involved in the process of end-of-life decision making in intensive care units. Ethnographic study. Data were collected via participant observation with field notes and semistructured interviews on 4 intensive care units in an academic health center in the mid-Atlantic United States from 2001 to 2004. The units studied were a medical, a surgical, a burn and trauma, and a cardiovascular intensive care unit. Health care clinicians, patients, and family members. Informal roles for family members consistently observed were primary caregiver, primary decision maker, family spokesperson, out-of-towner, patient's wishes expert, protector, vulnerable member, and health care expert. The identified informal roles were part of families' decision-making processes, and each role was part of a potentially complicated family dynamic for end-of-life decision making within the family system and between the family and health care domains. These informal roles reflect the diverse responses to demands for family decision making in what is usually a novel and stressful situation. Identification and description of these informal roles of family members can help clinicians recognize and understand the functions of these roles in families' decision making at the end of life and guide development of strategies to support and facilitate increased effectiveness of family discussions and decision-making processes.

  17. By-person factor analysis in clinical ethical decision making: Q methodology in end-of-life care decisions.

    PubMed

    Wong, William; Eiser, Arnold R; Mrtek, Robert G; Heckerling, Paul S

    2004-01-01

    To determine the usefulness of Q methodology to locate and describe shared subjective influences on clinical decision making among participant physicians using hypothetical cases containing common ethical issues. Qualitative study using by-person factor analysis of subjective Q sort data matrix. University medical center. Convenience sample of internal medicine attending physicians and house staff (n = 35) at one midwestern academic health sciences center. Presented with four hypothetical cases involving urgent decision making near the end of life, participants selected one of three specific clinical actions offered for each case. Immediately afterward and while considering their decision, each respondent sorted twenty-five subjective self-referent items in terms of the influence of each statement on their decision-making process. By-person factor analysis, where participants are defined as variates, yielded information about the attitudinal background the physicians brought to their consideration of each hypothetical case. We performed a second-order factor analysis on all of the subjective viewpoints to determine if a smaller core of shared attitudes existed across some or all of the four case vignettes. Factor scores for each item and post-sort comments from interviews conducted individually with each respondent guided the interpretation of ethical perspective used by these respondents in making clinical decisions about the cases. Second-order factor analysis on seventeen viewpoints used by physicians in the four hypothetical urgent decision cases revealed three moderately correlated (r2 < 40%) subjective core attitudinal guides used broadly among all the cases and among sixteen of the seventeen original factors. Across all the cases, our participants were guided in general by: (1) patient-focused beneficence, (2) a patient- and surrogate-focused perspective that includes risk avoidance, and (3) best interest of the patient guided by ethical values. Economic

  18. Timing of seasonal migration in mule deer: effects of climate, plant phenology, and life-history characteristics

    USGS Publications Warehouse

    Monteith, Kevin L.; Bleich, Vernon C.; Stephenson, Thomas R.; Pierce, Beck M.; Conner, Mary M.; Klaver, Robert W.; Bowyer, R. Terry

    2011-01-01

    Phenological events of plants and animals are sensitive to climatic processes. Migration is a life-history event exhibited by most large herbivores living in seasonal environments, and is thought to occur in response to dynamics of forage and weather. Decisions regarding when to migrate, however, may be affected by differences in life-history characteristics of individuals. Long-term and intensive study of a population of mule deer (Odocoileus hemionus) in the Sierra Nevada, California, USA, allowed us to document patterns of migration during 11 years that encompassed a wide array of environmental conditions. We used two new techniques to properly account for interval-censored data and disentangle effects of broad-scale climate, local weather patterns, and plant phenology on seasonal patterns of migration, while incorporating effects of individual life-history characteristics. Timing of autumn migration varied substantially among individual deer, but was associated with the severity of winter weather, and in particular, snow depth and cold temperatures. Migratory responses to winter weather, however, were affected by age, nutritional condition, and summer residency of individual females. Old females and those in good nutritional condition risked encountering severe weather by delaying autumn migration, and were thus risk-prone with respect to the potential loss of foraging opportunities in deep snow compared with young females and those in poor nutritional condition. Females that summered on the west side of the crest of the Sierra Nevada delayed autumn migration relative to east-side females, which supports the influence of the local environment on timing of migration. In contrast, timing of spring migration was unrelated to individual life-history characteristics, was nearly twice as synchronous as autumn migration, differed among years, was related to the southern oscillation index, and was influenced by absolute snow depth and advancing phenology of plants

  19. Real-life decision making in college students. II: Do individual differences show reliable effects?

    PubMed

    Galotti, Kathleen M; Tandler, Jane M; Wiener, Hillary J D

    2014-01-01

    First-year undergraduates participated in a short-term longitudinal study of real-life decision making over their first 14 months of college. They were surveyed about 7 different decisions: choosing courses for upcoming terms (on 3 different occasions), choosing an academic major (twice), planning for the upcoming summer, and planning for sophomore-year housing. They also completed a survey of self-reported decision-making styles and the Need for Cognition survey (Cacioppo & Petty, 1982) to assess their focus on rationality and enjoyment of analytic thinking. Results showed few statistically significant correlations between stylistic measures and behavioral measures of decision making, in either the amount of information considered or the way in which the information integration tracked predictions of linear models of decision making applied to each participant's data. However, there were consistent correlations, across the 7 decisions, between stylistic measures and affective reactions to, or retrospective descriptions of, episodes of decision making. We suggest that decision-making styles instruments may better reflect the construction of narratives of self as a decision maker more than they do actual behavior during decision making.

  20. Copepod reproductive strategies: life-history theory, phylogenetic pattern and invasion of inland waters

    NASA Astrophysics Data System (ADS)

    Hairston, Nelson G.; Bohonak, Andrew J.

    1998-06-01

    Life-history theory predicts that different reproductive strategies should evolve in environments that differ in resource availability, mortality, seasonality, and in spatial or temporal variation. Within a population, the predicted optimal strategy is driven by tradeoffs that are mediated by the environment in which the organisms live. At the same time, phylogenetic history may circumscribe natural selection by dictating the range of phenotypes upon which selection can act, or by limiting the range of environments encountered. Comparisons of life-history patterns in related organisms provide a powerful tool for understanding both the nature of selection on life-history characters and the diversity of life-history patterns observed in nature. Here, we explore reproductive strategies of the Copepoda, a well defined group with many phylogenetically independent transitions from free-living to parasitic life styles, from marine to inland waters, and from active development to diapause. Most species are iteroparous annuals, and most (with the exception of some parasitic taxa) develop through a relatively restricted range of life-history stages (nauplii and copepodids, or some modification thereof). Within these bounds, we suggest that there may be a causal relationship between the success of numerous copepod taxa in inland waters and the prevalence of either diapause or parasitism within these groups. We hypothesize that inland waters are more variable spatially and temporally than marine habitats, and accordingly, we interpret diapause and parasitism as mechanisms for coping with environmental variance.

  1. Life history migrations of adult Yellowstone Cutthroat Trout in the upper Yellowstone River

    USGS Publications Warehouse

    Ertel, Brian D.; McMahon, Thomas E.; Koel, Todd M.; Gresswell, Robert E.; Burckhardt, Jason

    2017-01-01

    Knowledge of salmonid life history types at the watershed scale is increasingly recognized as a cornerstone for effective management. In this study, we used radiotelemetry to characterize the life history movements of Yellowstone Cutthroat Trout Oncorhynchus clarkii bouvieri in the upper Yellowstone River, an extensive tributary that composes nearly half of the drainage area of Yellowstone Lake. In Yellowstone Lake, Yellowstone Cutthroat Trout have precipitously declined over the past 2 decades primarily due to predation from introduced Lake Trout Salvelinus namaycush. Radio tags were implanted in 152 Yellowstone Cutthroat Trout, and their movements monitored over 3 years. Ninety-six percent of tagged trout exhibited a lacustrine–adfluvial life history, migrating upstream a mean distance of 42.6 km to spawn, spending an average of 24 d in the Yellowstone River before returning to Yellowstone Lake. Once in the lake, complex postspawning movements were observed. Only 4% of radio-tagged trout exhibited a fluvial or fluvial–adfluvial life history. Low prevalence of fluvial and fluvial–adfluvial life histories was unexpected given the large size of the upper river drainage. Study results improve understanding of life history diversity in potamodromous salmonids inhabiting relatively undisturbed watersheds and provide a baseline for monitoring Yellowstone Cutthroat Trout response to management actions in Yellowstone Lake.

  2. Rapid Life-History Diversification of an Introduced Fish Species across a Localized Thermal Gradient

    PubMed Central

    Zhu, Fengyue; Rypel, Andrew L.; Murphy, Brian R.; Li, Zhongjie; Zhang, Tanglin; Yuan, Jing; Guo, Zhiqiang; Tang, Jianfeng; Liu, Jiashou

    2014-01-01

    Climatic variations are known to engender life-history diversification of species and populations at large spatial scales. However, the extent to which microgeographic variations in climate (e.g., those occurring within a single large ecosystem) can also drive life-history divergence is generally poorly documented. We exploited a spatial gradient in water temperatures at three sites across a large montane lake in southwest China (Lake Erhai) to examine the extent to which life histories of a short-lived fish species (icefish, Neosalanx taihuensis) diversified in response to thermal regime following introduction 25 y prior. In general, warmwater icefish variants grew faster, had larger adult body size and higher condition and fecundity, but matured at smaller sizes. Conversely, coldwater variants had smaller adult body size and lower condition, but matured at larger sizes and had larger eggs. These life-history differences strongly suggest that key ecological trade-offs exist for icefish populations exposed to different thermal regimes, and these trade-offs have driven relatively rapid diversification in the life histories of icefish within Lake Erhai. Results are surprisingly concordant with current knowledge on life-history evolution at macroecological scales, and suggest that improved conservation management might be possible by focusing on patterns operating at microgeographical, including, within-ecosystem scales. PMID:24505366

  3. The genomic and physiological basis of life history variation in a butterfly metapopulation.

    PubMed

    Klepsatel, Peter; Flatt, Thomas

    2011-05-01

    Unravelling the mechanisms underlying variation in life history traits is of fundamental importance for our understanding of adaptation by natural selection. While progress has been made in mapping fitness-related phenotypes to genotypes, mainly in a handful of model organisms, functional genomic studies of life history adaptations are still in their infancy. In particular, despite a few notable exceptions, the genomic basis of life history variation in natural populations remains poorly understood. This is especially true for the genetic underpinnings of life history phenotypes subject to diversifying selection driven by ecological dynamics in patchy environments--as opposed to adaptations involving strong directional selection owing to major environmental changes, such as latitudinal gradients, extreme climatic events or transitions from salt to freshwater. In this issue of Molecular Ecology,Wheat et al. (2011) now make a significant leap forward by applying the tools of functional genomics to dispersal-related life history variation in a butterfly metapopulation. Using a combination of microarrays, quantitative PCR and physiological measurements, the authors uncover several metabolic and endocrine factors that likely contribute to the observed life history phenotypes. By identifying molecular candidate mechanisms of fitness variation maintained by dispersal dynamics in a heterogeneous environment,they also begin to address fascinating interactions between the levels of physiology, ecology and evolution.

  4. Life history variation in a marine teleost across a heterogeneous seascape

    NASA Astrophysics Data System (ADS)

    Sala-Bozano, Maria; Mariani, Stefano

    2011-05-01

    Life history traits, primarily related to growth and reproduction, often reflect the process of adaptation of organisms to their natural environment. Consequently, life history parameters are expected to differ along heterogeneous habitats. Provided the pivotal role of life-history traits in determining fitness, the description and understanding of life history variation is a central goal in evolutionary ecology. In order to test the influence of the known environmental heterogeneity of Mediterranean coastal seas, populations of the striped sea bream Lithognathus mormyrus, were sampled from five distinct geographic areas within, or adjacent to, the Mediterranean basin (Aborán Sea, Balearic Sea, Tyrrhenian Sea, Adriatic Sea and the Gulf of Cadiz in the Atlantic Ocean). Growth patterns, maturation, sex-ratio, sex change and feeding habits were investigated over two years and revealed large-scale life history variation. Similarly slanted growth, earlier maturation times and smaller size-at-sex change were found in the Tyrrhenian and the Adriatic populations, which appear in contrast with recent population genetic investigation. The potential influence of fishery exploitation on these traits is discussed as a possible determining factor. The present study provides an exemplar of life-history variation across a heterogeneous seascape and makes a case for a more judicious consideration of ecological information for the purpose of identifying population units for management and conservation.

  5. A life history study of the yellow throat

    USGS Publications Warehouse

    Stewart, R.E.

    1953-01-01

    Investigations concerning the life history of the Yellow-throat were made in southern Michigan during the spring and summer of 1938. Supplementary information was also obtained at Arlington, Virginia, in 1940 and at the Patuxent Research Refuge, Maryland, in 1947.....Resident males established territories almost immediately upon arrival in spring. In southern Michigan some resident males arrived at least as soon as, if not before, transient males. Most females appeared on their nesting ground about a week later. Adults were engaged in nesting activities from the time of their arrival in spring until the advent of the post-nuptial molt in late summer.....Typical Yellow-throat habitat consists of a mixture of a dense herbaceous vegetation and small woody plants in damp or wet situations. At Ann Arbor, the Yellow-throat was a common breeding species in its restricted suitable habitat. The population density in one area of suitable habitat was about 69 territorial males per 100 acres. Of 11 territorial males that were intensively studied, one was polygamous (with two mates), nine were monogamous, and one was probably monogamous (with at least one mate).....The song of the individual Yellow-throat was heard throughout the breeding season except for the courtship period. Two major types of song were the common song given while perched, and an occasional, more elaborate, flight song. Most males sing in spurts, singing at fairly regular intervals for a considerable period and then abruptly ceasing for another period. The vocabulary of both sexes included several types of call notes that appeared either to have special functions or to represent outward expressions of distinct emotional states of the bird.....Resident males were antagonistic toward each other throughout the breeding season. Most remained on well-established territories during this period. Territories of 10 monogamous males ranged in size from .8 to 1.8 acres but the territory of one polygamous male occupied

  6. End-of-Life Decisions: A Cross-National Study of Treatment Preference Discussions and Surrogate Decision-Maker Appointments

    PubMed Central

    Evans, Natalie; Pasman, H. Roeline; Vega Alonso, Tomás; Van den Block, Lieve; Miccinesi, Guido; Van Casteren, Viviane; Donker, Gé; Bertolissi, Stefano; Zurriaga, Oscar; Deliens, Luc; Onwuteaka-Philipsen, Bregje; EUROIMPACT, on behalf of

    2013-01-01

    Background Making treatment decisions in anticipation of possible future incapacity is an important part of patient participation in end-of-life decision-making. This study estimates and compares the prevalence of GP-patient end-of-life treatment discussions and patients’ appointment of surrogate decision-makers in Italy, Spain, Belgium and the Netherlands and examines associated factors. Methods A cross-sectional, retrospective survey was conducted with representative GP networks in four countries. GPs recorded the health and care characteristics in the last three months of life of 4,396 patients who died non-suddenly. Prevalences were estimated and logistic regressions were used to examine between country differences and country-specific associated patient and care factors. Results GP-patient discussion of treatment preferences occurred for 10%, 7%, 25% and 47% of Italian, Spanish, Belgian and of Dutch patients respectively. Furthermore, 6%, 5%, 16% and 29% of Italian, Spanish, Belgian and Dutch patients had a surrogate decision-maker. Despite some country-specific differences, previous GP-patient discussion of primary diagnosis, more frequent GP contact, GP provision of palliative care, the importance of palliative care as a treatment aim and place of death were positively associated with preference discussions or surrogate appointments. A diagnosis of dementia was negatively associated with preference discussions and surrogate appointments. Conclusions The study revealed a higher prevalence of treatment preference discussions and surrogate appointments in the two northern compared to the two southern European countries. Factors associated with preference discussions and surrogate appointments suggest that delaying diagnosis discussions impedes anticipatory planning, whereas early preference discussions, particularly for dementia patients, and the provision of palliative care encourage participation. PMID:23472122

  7. Work-life balance: history, costs, and budgeting for balance.

    PubMed

    Raja, Siva; Stein, Sharon L

    2014-06-01

    The concept and difficulties of work-life balance are not unique to surgeons, but professional responsibilities make maintaining a work-life balance difficult. Consequences of being exclusively career focused include burn out, physical, and mental ailments. In addition, physician burn out may hinder optimal patient care and incur significant costs on health care in general. Assessing current uses of time, allocating goals catered to an individual surgeon, and continual self-assessment may help balance time, and ideally will help prevent burn out.

  8. Work–Life Balance: History, Costs, and Budgeting for Balance

    PubMed Central

    Raja, Siva; Stein, Sharon L.

    2014-01-01

    The concept and difficulties of work–life balance are not unique to surgeons, but professional responsibilities make maintaining a work–life balance difficult. Consequences of being exclusively career focused include burn out, physical, and mental ailments. In addition, physician burn out may hinder optimal patient care and incur significant costs on health care in general. Assessing current uses of time, allocating goals catered to an individual surgeon, and continual self-assessment may help balance time, and ideally will help prevent burn out. PMID:25067921

  9. The Influence of Mortality and Socioeconomic Status on Risk and Delayed Rewards: A Life History Theory Approach

    PubMed Central

    Griskevicius, Vladas; Tybur, Joshua M.; Delton, Andrew W.; Robertson, Theresa E.

    2012-01-01

    Why do some people take risks and live for the present, whereas others avoid risks and save for the future? The evolutionary framework of life history theory predicts that preferences for risk and delay in gratification should be influenced by mortality and resource scarcity. A series of experiments examined how mortality cues influenced decisions involving risk preference (e.g., $10 for sure vs. 50% chance of $20) and temporal discounting (e.g., $5 now vs. $10 later). The effect of mortality depended critically on whether people grew up in a relatively resource-scarce or resource-plentiful environment. For individuals who grew up relatively poor, mortality cues led them to value the present and gamble for big immediate rewards. Conversely, for individuals who grew up relatively wealthy, mortality cues led them to value the future and avoid risky gambles. Overall, mortality cues appear to propel individuals toward diverging life history strategies as a function of childhood socioeconomic status, suggesting important implications for how environmental factors influence economic decisions and risky behaviors. PMID:21299312

  10. End-of-life decisions in newborns: an approach from The Netherlands.

    PubMed

    Verhagen, A A E; Sauer, P J J

    2005-09-01

    End-of-life decisions in newborns with incurable conditions are especially difficult for pediatricians if they regard the group of stable infants with a hopeless prognosis, not dependent on technology. If a life full of severe and sustained suffering that cannot be relieved by any other means is expected, deliberate ending of life can be an acceptable choice in the Netherlands under very strict conditions. To increase the quality of the decision-making process and facilitate the mandatory reporting of life-ending procedures, a set of medical and legal guidelines (the Groningen protocol) was made in our institution in collaboration with the district attorney. This protocol serves as a tool to bring newborn euthanasia under a regime of effective control. This article describes the present approach to life-ending measures in newborns in the Netherlands and gives an overview of the protocol.

  11. The Tsimane Health and Life History Project: Integrating anthropology and biomedicine.

    PubMed

    Gurven, Michael; Stieglitz, Jonathan; Trumble, Benjamin; Blackwell, Aaron D; Beheim, Bret; Davis, Helen; Hooper, Paul; Kaplan, Hillard

    2017-04-01

    The Tsimane Health and Life History Project, an integrated bio-behavioral study of the human life course, is designed to test competing hypotheses of human life-history evolution. One aim is to understand the bidirectional connections between life history and social behavior in a high-fertility, kin-based context lacking amenities of modern urban life (e.g. sanitation, banks, electricity). Another aim is to understand how a high pathogen burden influences health and well-being during development and adulthood. A third aim addresses how modernization shapes human life histories and sociality. Here we outline the project's goals, history, and main findings since its inception in 2002. We reflect on the implications of current findings and highlight the need for more coordinated ethnographic and biomedical study of contemporary nonindustrial populations to address broad questions that can situate evolutionary anthropology in a key position within the social and life sciences. © 2017 The Authors Evolutionary Anthropology: Issues, News, and Reviews Published by Wiley Periodicals, Inc.

  12. End-of-life decisions in intensive care medicine-shared decision-making and intensive care unit length of stay.

    PubMed

    Graw, Jan A; Spies, Claudia D; Kork, Felix; Wernecke, Klaus-D; Braun, Jan-Peter

    2015-03-01

    Most deaths on the intensive care unit (ICU) occur after end-of-life decisions (EOLD) have been made. During the decision-making process, responsibility is often shared within the caregiver team and with the patients' surrogates. The intensive care unit length of stay (ICU-LOS) of surgical ICU-patients depends on the primary illness as well as on the past medical history. Whether an increasing ICU-LOS affects the process of EOLD making is unknown. A retrospective analysis was conducted on all deceased patients (n = 303) in a 22-bed surgical ICU of a German university medical center. Patient characteristics were compared between surgical patients with an ICU-LOS up to 1 week and those with an ICU-LOS of more than 7 days. Deceased patients with a long ICU-LOS received more often an EOLD (83.2% vs. 63.6%, p = 0.001). Groups did not differ in urgency of admission. Attending intensivists participated in every EOLD. Participation of surgeons was significantly higher in patients with a short ICU-LOS (24.1%, p = 0.003), whereas nurses and the patients' surrogates were involved more frequently in patients with a long ICU-LOS (18.8%, p = 0.021 and 18.9%, p = 0.018, respectively). EOLDs of surgical ICU-patients are associated with the ICU-LOS. Reversal of the primary illness leads the early ICU course, while in prolonged ICU-LOS, the patients' predicted will and the expected post-ICU-quality of life gain interest. Nurses and the patients' surrogates participate more frequently in EOLDs with prolonged ICU-LOS. To improve EOLD making on surgical ICUs, the ICU-LOS associated participation of the different decision makers needs further prospective analysis.

  13. Immediate and delayed life history effects caused by food deprivation early in life in a short-lived lizard.

    PubMed

    Mugabo, M; Marquis, O; Perret, S; LE Galliard, J F

    2010-09-01

    Detailed studies of the mechanisms driving life history effects of food availability are of prime importance to understand the evolution of phenotypic plasticity and the capacity of organisms to produce better adapted phenotypes. Food availability may influence life history trajectories through three nonexclusive mechanisms: (i) immediate and long-lasting effects on individual quality, and indirect delayed effects on (ii) intracohort and (iii) intercohort interactions. Using the common lizard (Zootoca vivipara), we tested whether a food deprivation during the two-first months of life influence life history (growth, survival, reproduction) and performance traits (immunocompetence, locomotor performances) until adulthood. We investigated the underlying mechanisms and their possible interactions by manipulating jointly food availability in a birth cohort and in cohorts of older conspecifics. Food deprivation had direct immediate negative effects on growth but positive long-lasting effects on immunocompetence. Food deprivation had also indirect delayed effects on growth, body size, early survival and reproduction mediated by an interaction between its direct effects on individual quality and its delayed effects on the intensity of intercohort social interactions combined with density dependence on body size. These results demonstrate that interactions between direct and socially mediated effects of past environments influence life history evolution in size-structured and stage-structured populations.

  14. Using Age-Based Life History Data to Investigate the Life Cycle and Vulnerability of Octopus cyanea

    PubMed Central

    Herwig, Jade N.; Depczynski, Martial; Roberts, John D.; Semmens, Jayson M.; Gagliano, Monica; Heyward, Andrew J.

    2012-01-01

    Octopus cyanea is taken as an unregulated, recreationally fished species from the intertidal reefs of Ningaloo, Western Australia. Yet despite its exploitation and importance in many artisanal fisheries throughout the world, little is known about its life history, ecology and vulnerability. We used stylet increment analysis to age a wild O. cyanea population for the first time and gonad histology to examine their reproductive characteristics. O. cyanea conforms to many cephalopod life history generalisations having rapid, non-asymptotic growth, a short life-span and high levels of mortality. Males were found to mature at much younger ages and sizes than females with reproductive activity concentrated in the spring and summer months. The female dominated sex-ratios in association with female brooding behaviours also suggest that larger conspicuous females may be more prone to capture and suggests that this intertidal octopus population has the potential to be negatively impacted in an unregulated fishery. Size at age and maturity comparisons between our temperate bordering population and lower latitude Tanzanian and Hawaiian populations indicated stark differences in growth rates that correlate with water temperatures. The variability in life history traits between global populations suggests that management of O. cyanea populations should be tailored to each unique set of life history characteristics and that stylet increment analysis may provide the integrity needed to accurately assess this. PMID:22912898

  15. Testing alternative hypotheses for variation in amphipod behaviour and life history in relation to parasitism.

    PubMed

    McCurdy, D G; Forbes, M R; Boates, J S

    1999-07-01

    We tested two hypotheses concerning changes in investment in current reproduction for parasitised hosts, using amphipods (Corophium volutator) which act as second intermediate hosts for trematodes (Gynaecoyla aduncta). One hypothesis requires that parasites exert control over their hosts (parasite manipulation), whereas the other predicts that hosts control decisions over investment (adaptive host response). Although these hypotheses are viewed as mutually exclusive, our various results support both hypotheses. For example, female amphipods infected by late-stage larvae were often found crawling at times when predation by sandpipers (Calidris pusilla), which are the final hosts for trematodes, was likely, while uninfected females typically remained in their burrows. Furthermore, old females that were newly-infected by trematodes often aborted and ate their young. Both of these responses seem inconsistent with female investment in current reproduction, but can be interpreted as adaptive parasite manipulation. In contrast, young non-ovigerous females that were newly-infected hastened the onset of their parturial moult and thus, time to becoming receptive. This response can be explained as a host adaptation to minimise the cost of parasites. We contend that differences between parasitised and unparasitised hosts in behaviour or investment can be explained as both parasite and host adaptations, expressed at different times in the host's life history. Such compromise will help explain the persistence of parasite-host associations in nature.

  16. Optimal life-history schedule in a metapopulation with juvenile dispersal.

    PubMed

    Cotto, O; Olivieri, I; Ronce, O

    2013-05-01

    Previous models have predicted that when mortality increases with age, older individuals should invest more of their resources in reproduction and produce less dispersive offspring, as both their future reproductive value and their prospect of competing with their own sib decline. Those models assumed stable population sizes. We here study for the first time the evolution of age-specific reproductive effort and of age-specific offspring dispersal rate in a metapopulation with extinction-recolonization dynamics and juvenile dispersal. Our model explores the evolutionary consequences of disequilibrium in the age structure of individuals in local populations, generated by disturbances. Life-history decisions are then shaped both by changes with age in individual performances, and by changes in ecological conditions, as young and old individuals do not live on average in the same environments. Lower juvenile dispersal favours the evolution of higher reproductive effort in young adults in a metapopulation with extinction-recolonization compared with a well-mixed population. Contrary to previous predictions for stable structured populations, we find that offspring dispersal should generally increase with maternal age. This is because young individuals, who are overrepresented in recently colonized populations, should allocate more to reproduction and less to dispersal as a strategy to exploit abundant recruitment opportunities in such populations. © 2013 The Authors. Journal of Evolutionary Biology © 2013 European Society For Evolutionary Biology.

  17. Early life history of three pelagic-spawning minnows Macrhybopsis spp. in the lower Missouri River.

    PubMed

    Starks, T A; Miller, M L; Long, J M

    2016-04-01

    Life-history characteristics of age-0 sturgeon chub Macrhybopsis gelida, shoal chub Macrhybopsis hyostoma and sicklefin chub Macrhybopsis meeki were compared using several methods. All Macrhybopsis species consumed mostly midge pupae, but M. meeki had the most general diet (Levins' index, B = 0.22) compared with M. hyostoma (B = 0.02) and M. gelida (B = 0.09). Morisita's diet overlap index among species pairs ranged from 0.62 to 0.97 and was highest between M. hyostoma and M. gelida. Daily ages estimated from lapilli otoliths for each species ranged from 15 to 43 days for M. gelida, 19 to 44 for M. hyostoma and from 16 to 64 days for M. meeki. Mean growth rates ranged from 0.79 mm day(-1) for M. meeki to 1.39 mm day(-1) for M. gelida. Mortality estimates indicated high daily survivorship rates for M. meeki (0.985), but could not be estimated for the other two species. Hatch date histograms were congruent with the belief that M. hyostoma and M. gelida spawn periodically from June to September. Macrhybopsis meeki, however, appeared to respond to a specific spawning cue as hatch dates were unimodal with a peak in July. These results fill a gap in current knowledge of these imperilled species that can be used to guide management decisions.

  18. The application of decision analysis to life support research and technology development

    NASA Technical Reports Server (NTRS)

    Ballin, Mark G.

    1994-01-01

    Applied research and technology development is often characterized by uncertainty, risk, and significant delays before tangible returns are obtained. Decision making regarding which technologies to advance and what resources to devote to them is a challenging but essential task. In the application of life support technology to future manned space flight, new technology concepts typically are characterized by nonexistent data and rough approximations of technology performance, uncertain future flight program needs, and a complex, time-intensive process to develop technology to a flight-ready status. Decision analysis is a quantitative, logic-based discipline that imposes formalism and structure to complex problems. It also accounts for the limits of knowledge that may be available at the time a decision is needed. The utility of decision analysis to life support technology R & D was evaluated by applying it to two case studies. The methodology was found to provide insight that is not possible from more traditional analysis approaches.

  19. The application of decision analysis to life support research and technology development

    NASA Technical Reports Server (NTRS)

    Ballin, Mark G.

    1994-01-01

    Applied research and technology development is often characterized by uncertainty, risk, and significant delays before tangible returns are obtained. Decision making regarding which technologies to advance and what resources to devote to them is a challenging but essential task. In the application of life support technology to future manned space flight, new technology concepts typically are characterized by nonexistent data and rough approximations of technology performance, uncertain future flight program needs, and a complex, time-intensive process to develop technology to a flight-ready status. Decision analysis is a quantitative, logic-based discipline that imposes formalism and structure to complex problems. It also accounts for the limits of knowledge that may be available at the time a decision is needed. The utility of decision analysis to life support technology R & D was evaluated by applying it to two case studies. The methodology was found to provide insight that is not possible from more traditional analysis approaches.

  20. The History of Black Star Picture Agency: "Life's" European Connection.

    ERIC Educational Resources Information Center

    Smith, C. Zoe

    Historians of photography have failed to explore the origins of the Black Star Picture Agency and how it introduced experienced photojournalists to Henry Luce, a publisher attempting to break new ground in American journalism with the introduction of a picture magazine, "Life," in 1936. Black Star's founders, Ernest Mayer, Kurt Kornfeld,…

  1. An unexpected life in optical science: a personal history

    NASA Astrophysics Data System (ADS)

    Bohren, Craig F.

    2010-02-01

    "The race is not to the swift, nor the battle to the strong, neither yet bread to the wise nor yet riches to men of understanding, nor yet favor to men of skill; but time and chance happeneth to them all." This in a nutshell describes the life and scientific career of Craig Bohren.

  2. Women in History--Abigail Adams: Life, Accomplishments, and Ideas

    ERIC Educational Resources Information Center

    Kenan, Sharon K.

    2008-01-01

    This article profiles the life, accomplishments, and ideas of Abigail Adams. Born in 1944, Adams lacked a formal education, but she more than made up for that shortcoming with her love of reading, especially literature, and her interests in politics and events surrounding the young colonies. Adams was supportive of the advancement of women. She…

  3. Women in History--Abigail Adams: Life, Accomplishments, and Ideas

    ERIC Educational Resources Information Center

    Kenan, Sharon K.

    2008-01-01

    This article profiles the life, accomplishments, and ideas of Abigail Adams. Born in 1944, Adams lacked a formal education, but she more than made up for that shortcoming with her love of reading, especially literature, and her interests in politics and events surrounding the young colonies. Adams was supportive of the advancement of women. She…

  4. [Life history interview--an effective approach to building positive doctor-patient relations and guide to proper end of life home care].

    PubMed

    Yamanashi, Hirotomo; Yamanashi, Irotomo; Miyamori, Tadashi

    2010-12-01

    The acclaimed psychiatrist, Arthur Kleinman, proposed Life History Interview as a way of enabling doctors to truly listen to a patient who is suffering from chronic disease. Two cases of terminally ill patients were carried out with Life History Interview. When speaking of the end of life home care, Life History Interview is an effective approach in building positive doctor-patient relations in the early stages. It truly allows for a good foundation for providing a proper care.

  5. Species Profiles. Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (South Florida). SNOOK,

    DTIC Science & Technology

    FISHES, *MARINE BIOLOGY , ADULTS, RECREATION, SEASONS, COMMERCIAL FISHING, ECOLOGY , ENVIRONMENTS, REQUIREMENTS, PRESSURE, BRACKISH WATER, INSHORE...AREAS, STREAMS, TIDES, COASTAL REGIONS, DEGRADATION, HABITATS, ENVIRONMENTAL IMPACT, ESTUARIES, FRESH WATER, OCEANS, INVERTEBRATES, HISTORY, LIFE( BIOLOGY ...LIMITATIONS, LOW LEVEL, LOW TEMPERATURE, POPULATION, SALTS, SWAMPS, PROFILES, YOUTH, DOCUMENTS, WATER, FISHERIES, FLORIDA, SOUTH(DIRECTION), TAXONOMY , LIFE CYCLES, REPRODUCTION(PHYSIOLOGY)

  6. Effect of Temperature on the life history of the mealybug, Paracoccus marginatus (Hemiptera: Pseudococcidae)

    USDA-ARS?s Scientific Manuscript database

    Effect of temperature on the life history of the mealybug, Paracoccus marginatus Williams and Granara de Willink was investigated in the laboratory. Paracoccus marginatus was able to develop and complete its life cycle at 18, 20, 25, and 30 ± 1°C. At 15, 34, and 35°C, the eggs hatched after 27, 6,...

  7. Anthropogenic natal environmental effects on life histories in a wild bird population.

    PubMed

    Cartwright, Samantha J; Nicoll, Malcolm A C; Jones, Carl G; Tatayah, Vikash; Norris, Ken

    2014-03-03

    Recent work suggests that the environment experienced in early life can alter life histories in wild populations, but our understanding of the processes involved remains limited. Since anthropogenic environmental change is currently having a major impact on wild populations, this raises the possibility that life histories may be influenced by human activities that alter environmental conditions in early life. Whether this is the case and the processes involved remain unexplored in wild populations. Using 23 years of longitudinal data on the Mauritius kestrel (Falco punctatus), a tropical forest specialist, we found that females born in territories affected by anthropogenic habitat change shifted investment in reproduction to earlier in life at the expense of late life performance. They also had lower survival rates as young adults. This shift in life history strategy appears to be adaptive, because fitness was comparable to that of other females experiencing less anthropogenic modification in their natal environment. Our results suggest that human activities can leave a legacy on wild birds through natal environmental effects. Whether these legacies have a detrimental effect on populations will depend on life history responses and the extent to which these reduce individual fitness.

  8. Hope Amidst Hopelessness: Life Histories of Illiterate Oraon Tribal Women in Jharkhand, India

    ERIC Educational Resources Information Center

    Minz, Nijhar Jharia

    2012-01-01

    This interpretive study asked the question: "What education and literacy insights can be gained from the studies of the life stories of illiterate Oraon women in Jharkhand, India?" Life history methodology was used to gain insights into the lived experiences of illiterate women. I hoped to provide meaning and give voice to the voiceless.…

  9. A review of Ruffe (Gymnocephalus cernuus) life history and implications for spread

    EPA Science Inventory

    Ruffe (Gymnocephalus cernuus) are among the most widespread fish invaders in Lake Superior. The objective of this study was to gather information on the complete life cycle of Ruffe in both their native and non-native ranges to characterize their life history strategies. A study ...

  10. A review of Ruffe (Gymnocephalus cernuus) life history and implications for spread

    EPA Science Inventory

    Ruffe (Gymnocephalus cernuus) are among the most widespread fish invaders in Lake Superior. The objective of this study was to gather information on the complete life cycle of Ruffe in both their native and non-native ranges to characterize their life history strategies. A study ...

  11. Sense of Control in End-of-Life Decision-Making.

    PubMed

    Romo, Rafael D; Allison, Theresa A; Smith, Alexander K; Wallhagen, Margaret I

    2017-03-01

    To explore how older adults in the community with a limited life expectancy make healthcare decisions and the processes used when they are not in an acute crisis. Grounded theory. Medical programs and geriatrics clinics at the University of California, San Francisco, and the San Francisco Veterans Affairs Medical Center. Community-dwelling adults aged 67 to 98 with a life expectancy of less than 1 year (N = 20). In-depth semistructured interviews in participants' homes. Constant comparative analysis was used to develop codes and identify themes. Participants generally delegated decisions to others, expressing their wishes by describing desired end-of-life outcomes and highlighting meaningful aspects of their lives. They did this in the belief that the delegate would make appropriate decisions on their behalf. In this way, participants were able to achieve a sense of control without being in control of decisions. Four themes emerged from the analysis that reflect the various approaches participants used to articulate their goals and maintain a sense of control: direct communication, third-party analogies, adaptive denial, and engaged avoidance. These findings challenge the prevailing view of personal autonomy. These older adults suggest a path to decision-making that focuses on priorities and goals, allowing them to take a more-passive approach to decision-making while still maintaining a sense of control. © 2016, Copyright the Authors Journal compilation © 2016, The American Geriatrics Society.

  12. The influence of life events on physical activity patterns of Dutch older adults: a life history method.

    PubMed

    Kenter, Elise J; Gebhardt, Winifred A; Lottman, Irene; van Rossum, Mariët; Bekedam, Margreet; Crone, Mathilde R

    2015-01-01

    Physical activity (PA) can improve well-being and health during older age. This study explored how life events influence PA patterns of older adults. Seventeen interviews with older adults were conducted using a life history method. PA patterns during the life course were identified, including information on when, how and why changes in PA occurred. Four different response patterns that affect PA patterns after life events (e.g. death of partner) were discerned as follows: 'I want to be physically active, but there are too many barriers', 'I have reached a point in my life where I do not have to be so active any more', 'I need to exercise now if I want to live the life I want' and 'I have always been active and cannot do without PA'. Which response pattern an older adult held was strongly related to PA development during earlier life (physical capital), and present and future self-conceptions. When developing interventions to enhance PA in older age, it is important to take into account the diversity of views on PA, based on physical capital and current and future self-conceptions. The life history method appeared valuable, providing a thorough understanding of changes in PA patterns.

  13. Convergent and correlated evolution of major life-history traits in the angiosperm genus Leucadendron (Proteaceae).

    PubMed

    Tonnabel, Jeanne; Mignot, Agnès; Douzery, Emmanuel J P; Rebelo, Anthony G; Schurr, Frank M; Midgley, Jeremy; Illing, Nicola; Justy, Fabienne; Orcel, Denis; Olivieri, Isabelle

    2014-10-01

    Natural selection is expected to cause convergence of life histories among taxa as well as correlated evolution of different life-history traits. Here, we quantify the extent of convergence of five key life-history traits (adult fire survival, seed storage, degree of sexual dimorphism, pollination mode, and seed-dispersal mode) and test hypotheses about their correlated evolution in the genus Leucadendron (Proteaceae) from the fire-prone South African fynbos. We reconstructed a new molecular phylogeny of this highly diverse genus that involves more taxa and molecular markers than previously. This reconstruction identifies new clades that were not detected by previous molecular study and morphological classifications. Using this new phylogeny and robust methods that account for phylogenetic uncertainty, we show that the five life-history traits studied were labile during the evolutionary history of the genus. This diversity allowed us to tackle major questions about the correlated evolution of life-history strategies. We found that species with longer seed-dispersal distances tended to evolve lower pollen-dispersal distance, that insect-pollinated species evolved decreased sexual dimorphism, and that species with a persistent soil seed-bank evolved toward reduced fire-survival ability of adults.

  14. A History of Spacecraft Environmental Control and Life Support Systems

    NASA Technical Reports Server (NTRS)

    Daues, Katherine R.

    2006-01-01

    A spacecraft's Environmental Control and Life Support (ECLS) system enables and maintains a habitable and sustaining environment for its crew. A typical ECLS system provides for atmosphere consumables and revitalization, environmental monitoring, pressure, temperature and humidity control, heat rejection (including equipment cooling), food and water supply and management, waste management, and fire detection and suppression. The following is a summary of ECLS systems used in United States (US) and Russian human spacecraft.

  15. Effects of maternal history of depression and early life maltreatment on children's health-related quality of life.

    PubMed

    Dittrich, Katja; Fuchs, Anna; Bermpohl, Felix; Meyer, Justus; Führer, Daniel; Reichl, Corinna; Reck, Corinna; Kluczniok, Dorothea; Kaess, Michael; Hindi Attar, Catherine; Möhler, Eva; Bierbaum, Anna-Lena; Zietlow, Anna-Lena; Jaite, Charlotte; Winter, Sibylle Maria; Herpertz, Sabine C; Brunner, Romuald; Bödeker, Katja; Resch, Franz

    2017-08-18

    There is a well-established link between maternal depression and child mental health. Similar effects have been found for maternal history of early life maltreatment (ELM). However, studies investigating the relationship of children's quality of life and maternal depression are scarce and none have been conducted for the association with maternal ELM. The aim of the present study was to investigate the effects of maternal history of ELM and depression on children's health-related quality of life and to identify mediating factors accounting for these effects. Our study involved 194 mothers with and without history of depression and/or ELM and their children between five and 12 years. Children's health-related quality of life was assessed by maternal proxy- and child self-ratings using the KIDSCREEN. We considered maternal sensitivity and maternal parenting stress as potential mediators. We found an effect of maternal history of depression but not of maternal history of ELM on health-related quality of life. Maternal stress and sensitivity mediated the effects of maternal depression on child global health-related quality of life, as well as on the dimensions Autonomy & Parent Relation, School Environment (maternal and child rating), and Physical Wellbeing (child rating). Due to the cross-sectional design of the study, causal interpretations must be made with caution. Some scales yielded low internal consistency. Maternal impairments in areas of parenting which possibly developed during acute depression persist even after remission of acute affective symptoms. Interventions should target parenting stress and sensitivity in parents with prior depression. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Cross-cultural Comparison of Learning in Human Hunting : Implications for Life History Evolution.

    PubMed

    MacDonald, Katharine

    2007-12-01

    This paper is a cross-cultural examination of the development of hunting skills and the implications for the debate on the role of learning in the evolution of human life history patterns. While life history theory has proven to be a powerful tool for understanding the evolution of the human life course, other schools, such as cultural transmission and social learning theory, also provide theoretical insights. These disparate theories are reviewed, and alternative and exclusive predictions are identified. This study of cross-cultural regularities in how children learn hunting skills, based on the ethnographic literature on traditional hunters, complements existing empirical work and highlights future areas for investigation.

  17. Species profiles: Life histories and environmental requirements of coastal fishes and invertebrates (Pacific Southwest): Pismo clam

    SciTech Connect

    Shaw, W.N.; Hassler, T.J.

    1989-02-01

    Species profile are literature summaries of the taxonomy, morphology, distribution, life history, and environmental requirements of coastal aquatic species. They are prepared to assist in environmental impact assessment. The Pismo clam (Tivela stultorum) supports an important sport fishery in the Pacific Southwest region, but has no present commercial importance. This review describes the life history (spawning, eggs, and larval stages, postlarvae and juveniles, maturity, and life-span), growth characteristics, former commercial and sport fisheries, ecological role, and environmental requirements. 30 refs., 4 figs., 3 tabs.

  18. Influence of life history traits on the population genetic structure of parasitic helminths: a minireview.

    PubMed

    Vazquez-Prieto, Severo; Vilas, Roman; Paniagua, Esperanza; Ubeira, Florencio M

    2015-11-06

    Parasite life history traits influence the rate of gene flow between populations and the effective population size, both of which determine the levels of genetic variability and the geographic distribution of such variability. In this short review targeted to parasitologists, we summarise how life history traits influence the population genetic structure of parasitic helminths. These organisms are characterised by a wide variety of life cycles and are ecologically different from microparasites, which have been studied in more detail. In order to provide the reader a concise review that illustrates key aspects of the subject matter, we have limited ourselves to studying examples selected for their clarity and relevance.

  19. [Insight into end-of-life decisions in newborns in Flanders, Belgium].

    PubMed

    Verhagen, A A E

    2006-02-18

    In the Netherlands, as in many other European countries, the majority of deaths in newborns are preceded by end-of-life decisions. In most cases, these decisions concern the withholding or withdrawing of treatment. Drugs with a potential life-shortening effect are often prescribed in the terminal phase of treatment of newborns to alleviate their suffering. The use of lethal drugs in order to deliberately end the life of newborns with a very poor prognosis and intractable severe suffering has been reported by Dutch paediatricians. Recently published data about end-of-life decisions in newborns in Flanders have shown that paediatricians in Flanders also consider the deliberate ending of life in newborns and young infants to be an acceptable option in exceptional circumstances. Real insight into the existing practice remains limited because the deliberate ending of life legally qualifies as murder in both countries. Few cases are reported because of the physician's fear of prosecution. Physicians in Flanders and in the Netherlands have pleaded for a different system of control of the deliberate ending of life in newborns. The Dutch government has recently announced the instalment of a multidisciplinary committee of experts to whom all cases must be reported. The advice of the committee to the prosecuting authorities will be crucial. It is expected that this change will increase the willingness to report cases.

  20. Theoretical life history responses of juvenile Oncorhynchus mykiss to changes in food availability using a dynamic state-dependent approach

    USGS Publications Warehouse

    Romine, Jason G.; Benjamin, Joseph R.; Perry, Russell W.; Casal, Lynne; Connolly, Patrick J.; Sauter, Sally S.

    2013-01-01

    Marine subsidies can play an important role in the growth, survival, and migratory behavior of rearing juvenile salmonids. Availability of high-energy, marine-derived food sources during critical decision windows may influence the timing of emigration or the decision to forego emigration completely and remain in the freshwater environment. Increasing growth and growth rate during these decision windows may result in an altered juvenile population structure, which will ultimately affect the adult population age-structure. We used a state dependent model to understand how the juvenile Oncorhynchus mykiss population structure may respond to increased availability of salmon eggs in their diet during critical decision windows. Our models predicted an increase in smolt production until coho salmon eggs comprised more than 50 percent of juvenile O. mykiss diet at the peak of the spawning run. At higher-than intermediate levels of egg consumption, smolt production decreased owing to increasing numbers of fish adopting a resident life-history strategy. Additionally, greater growth rates decreased the number of age-3 smolts and increased the number of age-2 smolts. Increased growth rates with higher egg consumption also decreased the age at which fish adopted the resident pathway. Our models suggest that the introduction of a high-energy food source during critical periods of the year could be sufficient to increase smolt production.

  1. Allometric scaling of production and life-history variation in vascular plants

    NASA Astrophysics Data System (ADS)

    Enquist, Brian J.; West, Geoffrey B.; Charnov, Eric L.; Brown, James H.

    1999-10-01

    A prominent feature of comparative life histories is the well documented negative correlation between growth rate and life span. Patterns of resource allocation during growth and reproduction reflect life-history differences between species. This is particularly striking in tropical forests, where tree species can differ greatly in their rates of growth and ages of maturity but still attain similar canopy sizes. Here we provide a theoretical framework for relating life-history variables to rates of production, dM/dt, where M is above-ground mass and t is time. As metabolic rate limits production as an individual grows, dM/dt ~ M3/4. Incorporating interspecific variation in resource allocation to wood density, we derive a universal growth law that quantitatively fits data for a large sample of tropical tree species with diverse life histories. Combined with evolutionary life-history theory, the growth law also predicts several qualitative features of tree demography and reproduction. This framework also provides a general quantitative answer to why relative growth rate (1/M)(dM/df) decreases with increasing plant size (~M-1/4) and how it varies with differing allocation strategies.

  2. The role of life histories and trophic interactions in population recovery.

    PubMed

    Audzijonyte, Asta; Kuparinen, Anna

    2016-08-01

    Factors affecting population recovery from depletion are at the focus of wildlife management. Particularly, it has been debated how life-history characteristics might affect population recovery ability and productivity. Many exploited fish stocks have shown temporal changes towards earlier maturation and reduced adult body size, potentially owing to evolutionary responses to fishing. Whereas such life-history changes have been widely documented, their potential role on stock's ability to recover from exploitation often remains ignored by traditional fisheries management. We used a marine ecosystem model parameterized for Southeastern Australian ecosystem to explore how changes towards "faster" life histories might affect population per capita growth rate r. We show that for most species changes towards earlier maturation during fishing have a negative effect (3-40% decrease) on r during the recovery phase. Faster juvenile growth and earlier maturation were beneficial early in life, but smaller adult body sizes reduced the lifetime reproductive output and increased adult natural mortality. However, both at intra- and inter-specific level natural mortality and trophic position of the species were as important in determining r as species longevity and age of maturation, suggesting that r cannot be predicted from life-history traits alone. Our study highlights that factors affecting population recovery ability and productivity should be explored in a multi-species context, where both age-specific fecundity and survival schedules are addressed simultaneously. It also suggests that contemporary life-history changes in harvested species are unlikely to increase their resilience and recovery ability.

  3. Repeated Lake-Stream Divergence in Stickleback Life History within a Central European Lake Basin

    PubMed Central

    Moser, Dario; Roesti, Marius; Berner, Daniel

    2012-01-01

    Life history divergence between populations inhabiting ecologically distinct habitats might be a potent source of reproductive isolation, but has received little attention in the context of speciation. We here test for life history divergence between threespine stickleback inhabiting Lake Constance (Central Europe) and multiple tributary streams. Otolith analysis shows that lake fish generally reproduce at two years of age, while their conspecifics in all streams have shifted to a primarily annual life cycle. This divergence is paralleled by a striking and consistent reduction in body size and fecundity in stream fish relative to lake fish. Stomach content analysis suggests that life history divergence might reflect a genetic or plastic response to pelagic versus benthic foraging modes in the lake and the streams. Microsatellite and mitochondrial markers further reveal that life history shifts in the different streams have occurred independently following the colonization by Lake Constance stickleback, and indicate the presence of strong barriers to gene flow across at least some of the lake-stream habitat transitions. Given that body size is known to strongly influence stickleback mating behavior, these barriers might well be related to life history divergence. PMID:23226528

  4. Age and life course location as interpretive resources for decisions regarding disclosure of HIV to parents and children: Findings from the HIV and later life study.

    PubMed

    Rosenfeld, Dana; Ridge, Damien; Catalan, Jose; Delpech, Valerie

    2016-08-01

    Studies of disclosure amongst older people living with HIV (PLWH) are uninformed by critical social-gerontological approaches that can help us to appreciate how older PLWH see and treat age as relevant to disclosure of their HIV status. These approaches include an ethnomethodologically-informed social constructionism that explores how 'the' life course (a cultural framework depicting individuals' movement through predictable developmental stages from birth to death) is used as an interpretive resource for determining self and others' characteristics, capacities, and social circumstances: a process Rosenfeld and Gallagher (2002) termed 'lifecoursing'. Applying this approach to our analysis of 74 life-history interviews and three focus groups with older (aged 50+) people living with HIV in the United Kingdom, we uncover the central role that lifecoursing plays in participants' decision-making surrounding disclosure of their HIV to their children and/or older parents. Analysis of participants' accounts uncovered four criteria for disclosure: the relevance of their HIV to the other, the other's knowledge about HIV, the likelihood of the disclosure causing the other emotional distress, and the other's ability to keep the disclosed confidential. To determine if these criteria were met in relation to specific children and/or elders, participants engaged in lifecoursing, evaluating the other's knowledge of HIV, and capacity to appropriately manage the disclosure, by reference to their age. The use of assumptions about age and life-course location in decision-making regarding disclosure of HIV reflects a more nuanced engagement with age in the disclosure decision-making process than has been captured by previous research into HIV disclosure, including on the part of people aging with HIV. Copyright © 2016 Elsevier Inc. All rights reserved.

  5. Life history and life tables of Bactericera cockerelli (Homoptera: Psyllidae) on eggplant and bell pepper.

    PubMed

    Yang, Xiang-Bing; Liu, Tong-Xian

    2009-12-01

    The development, survivorship, and fecundity of the potato psyllid, Bactericera cockerelli (Sulc), fed on eggplant (Solanum melongena L., variety Special Hibush) and bell pepper (Capsicum annuum L., variety Capsitrano) were studied in the laboratory at 26.7 +/- 2 degrees C, 70 +/- 5% RH, and at a photoperiod of 14:10 (L:D) h. Immature B. cockerelli developed faster (24.1 d) when fed on eggplant than on bell pepper (26.2 d). Survival rates of immature stages from egg to adult emergence were higher on eggplant (50.2%) than on bell pepper (34.6%). The longevity of B. cockerelli female adults fed on bell pepper was similar to that of females fed on eggplant (62.2 versus 55.0 d), but the male adults fed on eggplant lived shorter lives (39.4 d) than those fed on bell pepper (53.9 d). However, the preoviposition and oviposition periods, fecundity, and sex ratio of B. cockerelli fed on eggplant were not different from those fed on bell pepper. The r(m ) value and the finite rate of increase (lambda) of B. cockerelli were higher on eggplant (0.1099 and 1.116, respectively) than on bell pepper (0.0884 and 1.0924, respectively). Mean generation time and doubling time of B. cockerelli were shorter on eggplant (40.4 and 6.3 d, respectively) than on bell pepper (46.1 and 7.8 d, respectively). In contrast, lifetime fecundity of B. cockerelli was greater on bell pepper (227.3 offspring) than on eggplant (186.5 offspring). Based on these life history parameters, we concluded that B. cockerelli performed better on eggplant than on bell pepper.

  6. The French Society of Neonatology's proposals for neonatal end-of-life decision-making.

    PubMed

    Dageville, C; Bétrémieux, P; Gold, F; Simeoni, U

    2011-01-01

    Opinions and practice regarding end-of-life decisions in neonatal medicine show considerable variations between countries. A recent change of the legal framework, together with an ongoing debate among French neonatologists, led the French Society of Neonatology to reconsider and update its previous recommendations. To propose a set of recommendations on the ethical principles to be respected in the making and application of end-of-life decisions. A multidisciplinary working group on ethical issues in perinatal medicine composed of neonatologists, obstetricians and ethicists. Withholding or withdrawing life-sustaining treatment may be acceptable, and unreasonable therapeutic obstinacy is condemned. This implies that the child's best interests must always be the central consideration. Although the parents must be involved in the decision process so that they form an alliance with the healthcare team, and a collegial approach is of utmost importance, any crucial decision affecting the patient's life calls for individual medical responsibility. Because every newborn is rightfully an integral member of a human family, his or her dignity must be preserved. The goal of palliative care is to preserve the quality of a life, also at its end. The intention underlying an act has to be analyzed perceptively. Euthanasia, i.e. to perform an act with the deliberate intention to cause or hasten a patient's death, is legally and morally forbidden. Conversely, to withhold or withdraw a life-sustaining treatment can be justified when the intention is to cease opposing, in an unreasonable manner, the natural course of a disease. This statement provides the principles identified by French neonatologists on which to base their decisions concerning the ending of life. Arguments are set forth, discussed and compared with international statements and previously published considerations. Copyright © 2011 S. Karger AG, Basel.

  7. Linking habitat structure to life history strategy: Insights from a Mediterranean killifish

    NASA Astrophysics Data System (ADS)

    Cavraro, Francesco; Daouti, Irini; Leonardos, Ioannis; Torricelli, Patrizia; Malavasi, Stefano

    2014-01-01

    Modern theories of life history evolution deal with finding links between environmental factors, demographic structure of animal populations and the optimal life history strategy. Small-sized teleost fish, occurring in fragmented populations under contrasting environments, have been widely used as study models to investigate these issues. In the present study, the Mediterranean killifish Aphanius fasciatus was used to investigate the relationships between some habitat features and life history strategy. We selected four sites in the Venice lagoon inhabited by this species, exhibiting different combinations of two factors: overall adult mortality, related to intertidal water coverage and a consequent higher level of predator exposure, and the level of sediment organic matter, as indicator of habitat trophic richness. Results showed that these were the two most important factors influencing demography and life history traits in the four sites. Fish from salt marshes with high predator pressure were smaller and produced a higher number of eggs, whereas bigger fish and a lower reproductive investment were found in the two closed, not tidally influenced habitats. Habitat richness was positively related with population density, but negatively related with growth rate. In particular the synergy between high resources and low predation level was found to be important in shaping peculiar life history traits. Results were discussed in the light of the interactions between selective demographic forces acting differentially on age/size classes, such as predation, and habitat trophic richness that may represent an important energetic constraint on life history traits. The importance to link habitat productivity and morphology to demographic factors for a better understanding of the evolution of life history strategy under contrasting environments was finally suggested.

  8. Growth and life history variability of the grey reef shark (Carcharhinus amblyrhynchos) across its range

    PubMed Central

    Bradley, Darcy; Conklin, Eric; Papastamatiou, Yannis P.; McCauley, Douglas J.; Pollock, Kydd; Kendall, Bruce E.; Gaines, Steven D.; Caselle, Jennifer E.

    2017-01-01

    For broadly distributed, often overexploited species such as elasmobranchs (sharks and rays), conservation management would benefit from understanding how life history traits change in response to local environmental and ecological factors. However, fishing obfuscates this objective by causing complex and often mixed effects on the life histories of target species. Disentangling the many drivers of life history variability requires knowledge of elasmobranch populations in the absence of fishing, which is rarely available. Here, we describe the growth, maximum size, sex ratios, size at maturity, and offer a direct estimate of survival of an unfished population of grey reef sharks (Carcharhinus amblyrhynchos) using data from an eight year tag-recapture study. We then synthesized published information on the life history of C. amblyrhynchos from across its geographic range, and for the first time, we attempted to disentangle the contribution of fishing from geographic variation in an elasmobranch species. For Palmyra’s unfished C. amblyrhynchos population, the von Bertalanffy growth function (VBGF) growth coefficient k was 0.05 and asymptotic length L∞ was 163.3 cm total length (TL). Maximum size was 175.5 cm TL from a female shark, length at maturity was estimated at 116.7–123.2 cm TL for male sharks, maximum lifespan estimated from VBGF parameters was 18.1 years for both sexes combined, and annual survival was 0.74 year-1. Consistent with findings from studies on other elasmobranch species, we found significant intraspecific variability in reported life history traits of C. amblyrhynchos. However, contrary to what others have reported, we did not find consistent patterns in life history variability as a function of biogeography or fishing. Ultimately, the substantial, but not yet predictable variability in life history traits observed for C. amblyrhynchos across its geographic range suggests that regional management may be necessary to set sustainable harvest

  9. Connecting proximate mechanisms and evolutionary patterns: pituitary gland size and mammalian life history.

    PubMed

    Kamilar, J M; Tecot, S R

    2015-11-01

    At the proximate level, hormones are known to play a critical role in influencing the life history of mammals, including humans. The pituitary gland is directly responsible for producing several hormones, including those related to growth and reproduction. Although we have a basic understanding of how hormones affect life history characteristics, we still have little knowledge of this relationship in an evolutionary context. We used data from 129 mammal species representing 14 orders to investigate the relationship between pituitary gland size and life history variation. Because pituitary gland size should be related to hormone production and action, we predicted that species with relatively large pituitaries should be associated with fast life histories, especially increased foetal and post-natal growth rates. Phylogenetic analyses revealed that total pituitary size and the size of the anterior lobe of the pituitary significantly predicted a life history axis that was correlated with several traits including body mass, and foetal and post-natal growth rates. Additional models directly examining the association between relative pituitary size and growth rates produced concordant results. We also found that relative pituitary size variation across mammals was best explained by an Ornstein-Uhlenbeck model of evolution, suggesting an important role of stabilizing selection. Our results support the idea that the size of the pituitary is linked to life history variation through evolutionary time. This pattern is likely due to mediating hormone levels but additional work is needed. We suggest that future investigations incorporating endocrine gland size may be critical for understanding life history evolution. © 2015 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2015 European Society For Evolutionary Biology.

  10. Maturation characteristics and life history strategies of the Pacific Lamprey, Entosphenus tridentatus

    USGS Publications Warehouse

    Clemens, Benjamin J.; van de Wetering, Stan; Sower, Stacia A.; Schreck, Carl B.

    2013-01-01

    Lampreys (Petromyzontiformes) have persisted over millennia and now suffer a recent decline in abundance. Complex life histories may have factored in their persistence; anthropogenic perturbations in their demise. The complexity of life histories of lampreys is not understood, particularly for the anadromous Pacific lamprey, Entosphenus tridentatus Gairdner, 1836. Our goals were to describe the maturation timing and associated characteristics of adult Pacific lamprey, and to test the null hypothesis that different life histories do not exist. Females exhibited early vitellogenesis – early maturation stages; males exhibited spermatogonia – spermatozoa. Cluster analyses revealed an “immature” group and a “maturing–mature” group for each sex. We found statistically significant differences between these groups in the relationships between (i) body mass and total length in males; (ii) Fulton’s condition factor and liver lipids in males; (iii) the gonadosomatic index (GSI) and liver lipids in females; (iv) GSI and total length in females; (v) mean oocyte diameter and liver lipids; and (vi) mean oocyte diameter and GSI. We found no significant difference between the groups in the relationship of muscle lipids and body mass. Our analyses support rejection of the hypothesis of a single life history. We found evidence for an “ocean-maturing” life history that would likely spawn within several weeks of entering fresh water, in addition to the formerly recognized life history of spending 1 year in fresh water prior to spawning—the “stream-maturing” life history. Late maturity, semelparity, and high fecundity suggest that Pacific lamprey capitalize on infrequent opportunities for reproduction in highly variable environments.

  11. Eggshell Types and Their Evolutionary Correlation with Life-History Strategies in Squamates.

    PubMed

    Hallmann, Konstantin; Griebeler, Eva Maria

    2015-01-01

    The eggshell is an important physiological structure for the embryo. It enables gas exchange, physical protection and is a calcium reserve. Most squamates (lizards, snakes, worm lizards) lay parchment-shelled eggs, whereas only some gekkotan species, a subgroup of lizards, have strongly calcified eggshells. In viviparous (live-bearing) squamates the eggshell is reduced or completely missing (hereafter "shell-less"). Recent studies showed that life-history strategies of gekkotan species differ between species with parchment- and rigid-shelled eggshells. Here we test if the three different eggshell types found in the squamates are also associated with different life-history strategies. We first investigated the influence of the phylogeny on the trait "eggshell type" and on six life-history traits of 32 squamate species. Phylogenetic principal component analysis (pPCA) was then conducted to identify an association between life-history strategies and eggshell types. Finally, we also considered adult weight in the pPCA to examine its potential effect on this association. Eggshell types in squamates show a strong phylogenetic signal at a low taxonomical level. Four out of the six life-history traits showed also a phylogenetic signal (birth size, clutch size, clutches per year and age at female maturity), while two had none (incubation time, maximum longevity). The pPCA suggested an association of life-history strategies and eggshell types, which disappeared when adult weight was included in the analysis. We conclude that the variability seen in eggshell types of squamates is weakly influenced by phylogeny. Eggshell types correlate with different life-history strategies, and mainly reflect differences in adult weights of species.

  12. Eggshell Types and Their Evolutionary Correlation with Life-History Strategies in Squamates

    PubMed Central

    Hallmann, Konstantin; Griebeler, Eva Maria

    2015-01-01

    The eggshell is an important physiological structure for the embryo. It enables gas exchange, physical protection and is a calcium reserve. Most squamates (lizards, snakes, worm lizards) lay parchment-shelled eggs, whereas only some gekkotan species, a subgroup of lizards, have strongly calcified eggshells. In viviparous (live-bearing) squamates the eggshell is reduced or completely missing (hereafter “shell-less”). Recent studies showed that life-history strategies of gekkotan species differ between species with parchment- and rigid-shelled eggshells. Here we test if the three different eggshell types found in the squamates are also associated with different life-history strategies. We first investigated the influence of the phylogeny on the trait “eggshell type” and on six life-history traits of 32 squamate species. Phylogenetic principal component analysis (pPCA) was then conducted to identify an association between life-history strategies and eggshell types. Finally, we also considered adult weight in the pPCA to examine its potential effect on this association. Eggshell types in squamates show a strong phylogenetic signal at a low taxonomical level. Four out of the six life-history traits showed also a phylogenetic signal (birth size, clutch size, clutches per year and age at female maturity), while two had none (incubation time, maximum longevity). The pPCA suggested an association of life-history strategies and eggshell types, which disappeared when adult weight was included in the analysis. We conclude that the variability seen in eggshell types of squamates is weakly influenced by phylogeny. Eggshell types correlate with different life-history strategies, and mainly reflect differences in adult weights of species. PMID:26393343

  13. Growth and life history variability of the grey reef shark (Carcharhinus amblyrhynchos) across its range.

    PubMed

    Bradley, Darcy; Conklin, Eric; Papastamatiou, Yannis P; McCauley, Douglas J; Pollock, Kydd; Kendall, Bruce E; Gaines, Steven D; Caselle, Jennifer E

    2017-01-01

    For broadly distributed, often overexploited species such as elasmobranchs (sharks and rays), conservation management would benefit from understanding how life history traits change in response to local environmental and ecological factors. However, fishing obfuscates this objective by causing complex and often mixed effects on the life histories of target species. Disentangling the many drivers of life history variability requires knowledge of elasmobranch populations in the absence of fishing, which is rarely available. Here, we describe the growth, maximum size, sex ratios, size at maturity, and offer a direct estimate of survival of an unfished population of grey reef sharks (Carcharhinus amblyrhynchos) using data from an eight year tag-recapture study. We then synthesized published information on the life history of C. amblyrhynchos from across its geographic range, and for the first time, we attempted to disentangle the contribution of fishing from geographic variation in an elasmobranch species. For Palmyra's unfished C. amblyrhynchos population, the von Bertalanffy growth function (VBGF) growth coefficient k was 0.05 and asymptotic length L∞ was 163.3 cm total length (TL). Maximum size was 175.5 cm TL from a female shark, length at maturity was estimated at 116.7-123.2 cm TL for male sharks, maximum lifespan estimated from VBGF parameters was 18.1 years for both sexes combined, and annual survival was 0.74 year-1. Consistent with findings from studies on other elasmobranch species, we found significant intraspecific variability in reported life history traits of C. amblyrhynchos. However, contrary to what others have reported, we did not find consistent patterns in life history variability as a function of biogeography or fishing. Ultimately, the substantial, but not yet predictable variability in life history traits observed for C. amblyrhynchos across its geographic range suggests that regional management may be necessary to set sustainable harvest

  14. Spatial structuring of an evolving life-history strategy under altered environmental conditions.

    PubMed

    Hegg, Jens C; Kennedy, Brian P; Chittaro, Paul M; Zabel, Richard W

    2013-08-01

    Human disturbances to ecosystems have created challenges to populations worldwide, forcing them to respond phenotypically in ways that increase their fitness under current conditions. One approach to examining population responses to disturbance in species with complex life histories is to study species that exhibit spatial patterns in their phenotypic response across populations or demes. In this study, we investigate a threatened population of fall chinook salmon (Oncorhynchus tshawytscha) in the Snake River of Idaho, in which a significant fraction of the juvenile population have been shown to exhibit a yearling out-migration strategy which had not previously been thought to exist. It has been suggested that dam-related environmental changes may have altered the selective pressures experienced by out-migrating fall chinook, driving evolution of a later and more selectively advantageous migration strategy. Using isotopic analysis of otoliths from returning adult spawners, we reconstructed the locations of individual fish at three major juvenile life stages to determine if the representation of the yearling life history was geographically structured within the population. We reconstructed juvenile locations for natal, rearing and overwintering life stages in each of the major spawning areas in the basin. Our results indicate that the yearling life-history strategy is predominantly represented within one of the main spawning regions, the Clearwater River, rather than being distributed throughout the basin. Previous studies have shown the Clearwater River to have cooler temperatures, later hatch dates, and later outmigration of juveniles, indicating a link between environment and expression of the yearling life history. Our data suggest that this new yearling life history may be disproportionally represented in returning adult spawners, indicating selection for this life history within the population.

  15. Life lines: An art history of biological research around 1800.

    PubMed

    Bruhn, Matthias

    2011-12-01

    Around 1800, the scientific "illustrator" emerged as a new artistic profession in Europe. Artists were increasingly sought after in order to picture anatomical dissections and microscopic observations and to translate drawings into artworks for books and journals. By training and technical expertise, they introduced a particular kind of knowledge into scientific perception that also shaped the common image of nature. Illustrations of scientific publications, often undervalued as a biased interpretation of facts and subordinate to logic and description, thus convey an 'art history' of science in its own right, relevant both for the understanding of biological thought around 1800 as well as for the development of the arts and their historiography. The article is based on an analysis of botanical treatises produced for the Göttingen Society of Sciences in 1803, during an early phase of microscopic cell research, in order to determine the constitutive role of artistic knowledge and the media employed for the visualization and conceptualization of biological issues.

  16. Diversification and extinction in the history of life.

    PubMed

    Benton, M J

    1995-04-07

    Analysis of the fossil record of microbes, algae, fungi, protists, plants, and animals shows that the diversity of both marine and continental life increased exponentially since the end of the Precambrian. This diversification was interrupted by mass extinctions, the largest of which occurred in the Early Cambrian, Late Ordovician, Late Devonian, Late Permian, Early Triassic, Late Triassic, and end-Cretaceous. Most of these extinctions were experienced by both marine and continental organisms. As for the periodicity of mass extinctions, no support was found: Seven mass extinction peaks in the last 250 million years are spaced 20 to 60 million years apart.

  17. A brief history of the discovery of hyperthermophilic life.

    PubMed

    Stetter, Karl O

    2013-02-01

    Hyperthermophiles, growing optimally at 80°C and above were first discovered in 1981. They represent the upper temperature border of life and are found within water-containing terrestrial and submarine environments of active volcanism and geothermally heated subterranean rocks. The energy-yielding reactions represent mainly anaerobic and aerobic types of respiration rather than fermentation. Within the ss (single-stranded) rRNA phylogenetic tree, hyperthermophiles occupy all of the short deep branches closest to the root. Members of the deepest branch-offs are represented by the newly found Nanoarchaeota and Korarchaeota.

  18. Life History and Environmental Requirements of Loggerhead Turtles

    DTIC Science & Technology

    1988-08-01

    may become associated with sargassum rafts in the Gulf Stream (Caldwell 1968; Smith 1968; Fletemeyer 1978a, 1978b; Carr and Meylan 1980). Movement of...which which may contribute to the capture of indicates a maximum reproductive life turtles in trawls (Shoop and span of 32 years (i.e. it is unlikely...nesting exchange by sea turtle eggs. Am. at Melbourne Beach, Florida; I: Zool. 20(3):58. Size, growth, and reproductive biol- ogy. Biol. Conserv. 26:65-77

  19. Family communication and decision making at the end of life: a literature review.

    PubMed

    Wallace, Cara L

    2015-06-01

    Patients and families coping with a terminal illness are faced with a number of decisions over the course of their disease. The role that family communication plays in the process of decision making is an important one. The objectives for this review are to examine the current state of empirical literature on the relationship between family communication and decision making about end-of-life care, to identify gaps, and to discuss implications for policy, practice, and future research. Articles were identified using systematic keyword searches within the following relevant databases: Academic Search Complete, CINAHL Plus, Communications and Mass Media Complete, ERIC, PsychINFO, MEDLINE, SocINDEX, and ProQuest. The three bodies of relevant literature that emerged during this review include: (1) the importance of family communication at the end of life (EoL); (2) family decision making at the EoL; and (3) the interrelationship of communication (both within the family and with healthcare professionals) and decision making at the EoL. While the literature highlights the role of communication between medical professionals and the patient or family members, there is very little focus on the process of how family communication among the family members themselves contributes to decision making at the end of life. Barriers to end-of-life care are important considerations for helping patients to access timely and appropriate services. Understanding the pertinent role of family communication as it relates to the decision for EoL care is the first step in working to provide another avenue for overcoming these barriers.

  20. Life History Plasticity of a Tropical Seabird in Response to El Niño Anomalies during Early Life

    PubMed Central

    Ancona, Sergio; Drummond, Hugh

    2013-01-01

    Food shortage and other challenges associated with El Niño Southern Oscillation (ENSO) experienced early in life may have long-term impacts on life history traits, but these potential impacts remain virtually unexplored. By monitoring 2556 blue-footed boobies from 11 cohorts, we showed that birds facing warm water ENSO conditions (and probably low food availability) in the natal year were underweight at fledging, recruited earlier and bred less frequently, but showed no deficit in longevity or breeding success over the first 10 years. Life history impacts of ENSO were substantial when experienced in the prenatal year, the natal year, or the second year of life, and absent when experienced in the third year of life, implying that harsh conditions have greater effects when experienced earlier in life. Sexual differences in impacts depended on the age when warm water conditions were experienced: pre-natal and natal experience, respectively, induced early recruitment and influenced the relationship between age and laying date only in females, whereas second year experience reduced total breeding success only of males. Most surprising were positive transgenerational impacts in females: daughters of females that experienced ENSO conditions in their natal year showed improved breeding success. Developmental plasticity of boobies thus enables them to largely neutralize potential long-term impacts of harsh climatic conditions experienced early in life. PMID:24023760

  1. Life history plasticity of a tropical seabird in response to El Niño anomalies during early life.

    PubMed

    Ancona, Sergio; Drummond, Hugh

    2013-01-01

    Food shortage and other challenges associated with El Niño Southern Oscillation (ENSO) experienced early in life may have long-term impacts on life history traits, but these potential impacts remain virtually unexplored. By monitoring 2556 blue-footed boobies from 11 cohorts, we showed that birds facing warm water ENSO conditions (and probably low food availability) in the natal year were underweight at fledging, recruited earlier and bred less frequently, but showed no deficit in longevity or breeding success over the first 10 years. Life history impacts of ENSO were substantial when experienced in the prenatal year, the natal year, or the second year of life, and absent when experienced in the third year of life, implying that harsh conditions have greater effects when experienced earlier in life. Sexual differences in impacts depended on the age when warm water conditions were experienced: pre-natal and natal experience, respectively, induced early recruitment and influenced the relationship between age and laying date only in females, whereas second year experience reduced total breeding success only of males. Most surprising were positive transgenerational impacts in females: daughters of females that experienced ENSO conditions in their natal year showed improved breeding success. Developmental plasticity of boobies thus enables them to largely neutralize potential long-term impacts of harsh climatic conditions experienced early in life.

  2. Life history and environmental requirements of loggerhead turtles

    SciTech Connect

    Nelson, D.A.

    1988-08-01

    In the United States scattered nestings of loggerhead sea turtles (Caretta caretta) may occur in most of its range from Texas to Florida and Florida to New Jersey; however, nesting concentrations occur on coastal islands of North Carolina, South Carolina, and Georgia and on the coasts of Florida. The greatest portion of a loggerhead's life is spent in ocean and estuarine waters where it breeds in shallow waters adjacent to nesting beaches, feeds on a variety of fish and shellfish, and migrates generally north in the spring and summer and south in the fall and winter. The other part of its life is spent on coastal beaches where the female digs a nest, lays her eggs (average 120 eggs), the eggs hatch (in 46 to 65 days), and the hatchlings emerge from the nest as a group and orient seaward to become part of the aquatic system again. Nesting activity begins in the spring, peaks in midsummer, and declines until completion in late summer. A loggerhead female generally nests every other or every third year. Beach sand temperatures may affect nest site selection by females, the incubation time and hatching success of eggs, and the sex and emergence timing of hatchlings. Most management of sea turtles has been directed toward increasing hatching and hatchling success through predator control, egg relocation, and raising captive hatchlings. 183 refs.; 10 figs.; 3 tabs.

  3. Life or Death Decisions: Framing the Call for Help

    PubMed Central

    Chou, Eileen Y.; Murnighan, J. Keith

    2013-01-01

    Background Chronic blood shortages in the U.S. would be alleviated by small increases, in percentage terms, of people donating blood. The current research investigated the effects of subtle changes in charity-seeking messages on the likelihood of people responses to a call for help. We predicted that “avoid losses” messages would lead to more helping behavior than “promote gains” messages would. Method Two studies investigated the effects of message framing on helping intentions and behaviors. With the help and collaboration of the Red Cross, Study 1, a field experiment, directly assessed the effectiveness of a call for blood donations that was presented as either death-preventing (losses) or life-saving (gains), and as being of either more or less urgent need. With the help and collaboration of a local charity, Study 2, a lab experiment, assessed the effects of the gain-versus-loss framing of a donation-soliciting flyer on individuals’ expectations of others’ monetary donations as well their own volunteering behavior. Study 2 also assessed the effects of three emotional motivators - feelings of empathy, positive affect, and relational closeness. Result Study 1 indicated that, on a college campus, describing blood donations as a way to “prevent a death” rather than “save a life” boosted the donation rate. Study 2 showed that framing a charity’s appeals as helping people to avoid a loss led to larger expected donations, increased intentions to volunteer, and more helping behavior, independent of other emotional motivators. Conclusion This research identifies and demonstrates a reliable and effective method for increasing important helping behaviors by providing charities with concrete ideas that can effectively increase helping behavior generally and potentially death-preventing behavior in particular. PMID:23483903

  4. End of Life Decisions for Sealed Radioactive Sources

    SciTech Connect

    Pryor, Kathryn H.

    2016-02-29

    Sealed radioactive sources are encountered in a wide variety of settings – from household smoke detectors and instrument check sources, through fixed industrial gauges, industrial radiography and well logging sources, to irradiators and medical teletherapy devices. In general, the higher the level of activity in the sealed source, the stricter the regulatory control that is applied to its use, control and ultimate disposition. Lower levels of attention and oversight can and do lead to sources ending up in the wrong place – as orphan sources in uncontrolled storage, disposed in a sanitary landfill, melted down in metal recycling operations and incorporated into consumer products, or handled by an unsuspecting member of the public. There are a range of issues that contribute to the problem of improper disposal of sealed sources, and, in particular, to disused source disposal. General licensed sources and devices are particularly at risk of being disposed incorrectly. Higher activity general licensed sources, although required to be registered with the Nuclear Regulatory Commission (NRC) or Agreement State, receive limited regulatory oversight and are not tracked on a national scale. Users frequently do not consider the full life-cycle costs when procuring sources or devices and discover that they cannot afford to package, transport and dispose of their sources properly. The NRC requirements for decommissioning funding plans and financial assurance are not adequate to cover sealed source transport and disposal costs fully. While there are regulatory limits for storage of disused sources, enforcement is limited and there is no financial incentive for owners to dispose of the sources. In some cases, the lack of availability of approved Department of Transportation (DOT) Type B shipping casks also presents a barrier to sealed source disposal. The report of the Disused Sources Working Group does an excellent job of framing these issues. This article reviews both the

  5. Supporting decisions through the Study of Environmental Arctic Change (SEARCH) Program: A History and Way Forward

    NASA Astrophysics Data System (ADS)

    Druckenmiller, M. L.; Wiggins, H. V.; Eicken, H.; Francis, J. A.; Huntington, H.; Scambos, T. A.

    2015-12-01

    The Study of Environmental Arctic Change (SEARCH), ongoing since the early-2000s, aims to develop scientific knowledge to help society understand and respond to the rapidly changing Arctic. Through collaboration with the research community, funding agencies, national and international science programs, and other stakeholders, SEARCH facilitates research activities across local-to-global scales, with increasing emphasis on addressing the information needs of policy and decision-makers. This talk will explore the program's history, spanning its earliest efforts to understand interrelated atmospheric, oceanic, and terrestrial changes in the Arctic to more recent objectives of providing stakeholder-relevant information, such as community-wide summaries of the expected arctic summer sea ice minimum or up-to-date information on sea ice conditions to Alaska Native walrus hunters in the Bering and Chukchi Seas. We will discuss SEARCH's recent shift toward a "Knowledge to Action" vision and implementation of focused Action Teams to: (1) improve understanding, advance prediction, and explore consequences of changing arctic sea ice; (2) document and understand how degradation of near-surface permafrost will affect arctic and global systems; and (3) improve predictions of future land-ice loss and impacts on sea level. Tracking and evaluating how scientific information from such research reaches stakeholders and informs decisions are critical for interactions that allow the research community to keep pace with an evolving landscape of arctic decision-makers. Examples will be given for the new directions these Action Teams are taking regarding science communication and approaches for research community collaboration to synthesize research findings and promote arctic science and interdisciplinary scientific discovery.

  6. NARRATIVE: A short history of my life in science A short history of my life in science

    NASA Astrophysics Data System (ADS)

    Manson, Joseph R.

    2010-08-01

    I was certainly surprised, and felt extremely honored, when Salvador Miret-Artés suggested that he would like to organize this festschrift. Before that day I never anticipated that such an honor would come to me. I would like to thank Salvador for the large amount of time and work he has expended in organizing this special issue, the Editors of Journal of Physics: Condensed Matter for making it possible, and also the contributing authors for their efforts. My family home was outside of Petersburg, Virginia in Dinwiddie County in an area that was, during my youth, largely occupied by small farms. This is a region rich in American history and our earliest ancestors on both sides of the family settled in this area, beginning in the decade after the first Virginia settlement in Jamestown. My father was an engineer and my mother was a former school teacher, and their parents were small business owners. From earliest memories I recall being interested in finding out how things worked and especially learning about the wonders of nature. These interests were fostered by my parents who encouraged such investigations during long walks, visits to friends and relatives, and trips to museums. However, my earliest memory of wanting to become a scientist is associated with a Christmas gift of a chemistry set when I was about ten years old. I was absolutely fascinated by the amazing results that could be achieved with simple chemical reactions and realized then that I wanted to do something in life that would be associated with science. The gift of that small chemistry set developed over the next few years into a serious interest in chemistry, and throughout my junior high-school years I spent nearly all the money I earned doing odd jobs for neighbors on small laboratory equipment and chemical supplies, eventually taking over our old abandoned chicken house and turning it into a small chemistry lab. I remember being somewhat frustrated at the limits, mainly financial, that kept

  7. Gender, sexuality and the participatory dimensions of a comparative life history policy study.

    PubMed

    Macdonnell, Judith A

    2011-12-01

    Gender, sexuality and the participatory dimensions of a comparative life history policy study In this paper, I explore how a critical feminist lens was a crucial element in creating a participatory policy study which used a qualitative design and comparative life history methodology. This study focused on Canadian nurses' political practice related to advocacy for lesbian health. Findings show that the combination of the gender lens and life history approach offers potential to create knowledge in ways aligned with health-promoting and emancipatory outcomes. However, the nature of participation and interaction by researcher and participants is contexualized and contested given complex dynamics of power that shape all aspects of this doctoral study process. The critical feminist lens with its focus on reflexivity informed the content and process of knowledge production in this study and shaped key turning points: the ways in which this policy study was conceptualized, the choice of comparative life history methodology, ethical considerations, data collection and analysis and representation of findings. Life history is unlikely to be the methodology that first comes to mind when undertaking a policy study. Its historical roots are associated with biographical, oral history and narrative approaches, which typically aim to elicit understanding of lived experience. Yet, it was this very aspect, this focus on lived experience, which rendered life history methodology fitting as I contemplated how to examine the relationship between nurses and policy. I was interested in understanding nurses' political practice, how policy influenced nurses' capacity to advocate in their everyday lives, as well as nurses' impacts on policy processes and their larger social worlds. © 2011 Blackwell Publishing Ltd.

  8. Extraordinarily rapid life-history divergence between Cryptasterina sea star species

    PubMed Central

    Puritz, Jonathan B.; Keever, Carson C.; Addison, Jason A.; Byrne, Maria; Hart, Michael W.; Grosberg, Richard K.; Toonen, Robert J.

    2012-01-01

    Life history plays a critical role in governing microevolutionary processes such as gene flow and adaptation, as well as macroevolutionary processes such speciation. Here, we use multilocus phylogeographic analyses to examine a speciation event involving spectacular life-history differences between sister species of sea stars. Cryptasterina hystera has evolved a suite of derived life-history traits (including internal self-fertilization and brood protection) that differ from its sister species Cryptasterina pentagona, a gonochoric broadcast spawner. We show that these species have only been reproductively isolated for approximately 6000 years (95% highest posterior density of 905–22 628), and that this life-history change may be responsible for dramatic genetic consequences, including low nucleotide diversity, zero heterozygosity and no gene flow. The rapid divergence of these species rules out some mechanisms of isolation such as adaptation to microhabitats in sympatry, or slow divergence by genetic drift during prolonged isolation. We hypothesize that the large phenotypic differences between species relative to the short divergence time suggests that the life-history differences observed may be direct responses to disruptive selection between populations. We speculate that local environmental or demographic differences at the southern range margin are possible mechanisms of selection driving one of the fastest known marine speciation events. PMID:22810427

  9. Extraordinarily rapid life-history divergence between Cryptasterina sea star species.

    PubMed

    Puritz, Jonathan B; Keever, Carson C; Addison, Jason A; Byrne, Maria; Hart, Michael W; Grosberg, Richard K; Toonen, Robert J

    2012-10-07

    Life history plays a critical role in governing microevolutionary processes such as gene flow and adaptation, as well as macroevolutionary processes such speciation. Here, we use multilocus phylogeographic analyses to examine a speciation event involving spectacular life-history differences between sister species of sea stars. Cryptasterina hystera has evolved a suite of derived life-history traits (including internal self-fertilization and brood protection) that differ from its sister species Cryptasterina pentagona, a gonochoric broadcast spawner. We show that these species have only been reproductively isolated for approximately 6000 years (95% highest posterior density of 905-22 628), and that this life-history change may be responsible for dramatic genetic consequences, including low nucleotide diversity, zero heterozygosity and no gene flow. The rapid divergence of these species rules out some mechanisms of isolation such as adaptation to microhabitats in sympatry, or slow divergence by genetic drift during prolonged isolation. We hypothesize that the large phenotypic differences between species relative to the short divergence time suggests that the life-history differences observed may be direct responses to disruptive selection between populations. We speculate that local environmental or demographic differences at the southern range margin are possible mechanisms of selection driving one of the fastest known marine speciation events.

  10. The contribution of estuary-resident life histories to the return of adult Oncorhynchus kisutch.

    PubMed

    Jones, K K; Cornwell, T J; Bottom, D L; Campbell, L A; Stein, S

    2014-07-01

    This study evaluated estuarine habitat use, life-history composition, growth and survival of four successive broods of coho salmon Oncoryhnchus kisutch in Salmon River, Oregon, U.S.A. Subyearling and yearling O. kisutch used restored and natural estuarine wetlands, particularly in the spring and winter. Stream-reared yearling smolts spent an average of 2 weeks in the estuary growing rapidly before entering the ocean. Emergent fry also entered the estuary in the spring, and some resided in a tidal marsh throughout the summer, even as salinities increased to >20. A significant portion of the summer stream-resident population of juvenile O. kisutch migrated out of the catchment in the autumn and winter and used estuary wetlands and adjacent streams as alternative winter-rearing habitats until the spring when they entered the ocean as yearling smolts. Passive integrated transponder (PIT) tag returns and juvenile life-history reconstructions from otoliths of returning adults revealed that four juvenile life-history types contributed to the adult population. Estuarine-associated life-history strategies accounted for 20-35% of the adults returning to spawn in the four brood years, indicating that a sizable proportion of the total O. kisutch production is ignored by conventional estimates based on stream habitat capacity. Juvenile O. kisutch responses to the reconnection of previously unavailable estuarine habitats have led to greater life-history diversity in the population and reflect greater phenotypic plasticity of the species in the U.S. Pacific Northwest than previously recognized.

  11. The origin of parental care in relation to male and female life history.

    PubMed

    Klug, Hope; Bonsall, Michael B; Alonzo, Suzanne H

    2013-04-01

    The evolution of maternal, paternal, and bi-parental care has been the focus of a great deal of research. Males and females vary in basic life-history characteristics (e.g., stage-specific mortality, maturation) in ways that are unrelated to parental investment. Surprisingly, few studies have examined the effect of this variation in male and female life history on the evolution of care. Here, we use a theoretical approach to determine the sex-specific life-history characteristics that give rise to the origin of paternal, maternal, or bi-parental care from an ancestral state of no care. Females initially invest more into each egg than males. Despite this inherent difference between the sexes, paternal, maternal, and bi-parental care are equally likely when males and females are otherwise similar. Thus, sex differences in initial zygotic investment do not explain the origin of one pattern of care over another. However, sex differences in adult mortality, egg maturation rate, and juvenile survival affect the pattern of care that will be most likely to evolve. Maternal care is more likely if female adult mortality is high, whereas paternal care is more likely if male adult mortality is high. These findings suggest that basic life-history differences between the sexes can alone explain the origin of maternal, paternal, and bi-parental care. As a result, the influence of life-history characteristics should be considered as a baseline scenario in studies examining the origin of care.

  12. Life-history evolution in guppies VIII: the demographics of density regulation in guppies (Poecilia reticulata).

    PubMed

    Reznick, David N; Bassar, Ronald D; Travis, Joseph; Helen Rodd, F

    2012-09-01

    In prior research, we found the way guppy life histories evolve in response to living in environments with a high or low risk of predation is consistent with life-history theory that assumes no density dependence. We later found that guppies from high-predation environments experience higher mortality rates than those from low-predation environments, but the increased risk was evenly distributed across all age/size classes. Life-history theory that assumes density-independent population growth predicts that life histories will not evolve under such circumstances, yet we have shown with field introduction experiments that they do evolve. However, theory that incorporates density regulation predicts this pattern of mortality can result in the patterns of life-history evolution we had observed. Here we report on density manipulation experiments performed in populations of guppies from low-predation environments to ask whether natural populations normally experience density regulation and, if so, to characterize the short-term demographic changes that underlie density regulation. Our experiments reveal that these populations are density regulated. Decreased density resulted in higher juvenile growth, decreased juvenile mortality rates, and increased reproductive investment by adult females. Increased density causes reduced offspring size, decreased fat storage by adult females, and increased adult mortality. © 2012 The Author(s). Evolution© 2012 The Society for the Study of Evolution.

  13. Switch between life history strategies due to changes in glycolytic enzyme gene dosage in Saccharomyces cerevisiae.

    PubMed

    Wang, Shaoxiao; Spor, Aymé; Nidelet, Thibault; Montalent, Pierre; Dillmann, Christine; de Vienne, Dominique; Sicard, Delphine

    2011-01-01

    Adaptation is the process whereby a population or species becomes better fitted to its habitat through modifications of various life history traits which can be positively or negatively correlated. The molecular factors underlying these covariations remain to be elucidated. Using Saccharomyces cerevisiae as a model system, we have investigated the effects on life history traits of varying the dosage of genes involved in the transformation of resources into energy. Changing gene dosage for each of three glycolytic enzyme genes (hexokinase 2, phosphoglucose isomerase, and fructose-1,6-bisphosphate aldolase) resulted in variation in enzyme activities, glucose consumption rate, and life history traits (growth rate, carrying capacity, and cell size). However, the range of effects depended on which enzyme was expressed differently. Most interestingly, these changes revealed a genetic trade-off between carrying capacity and cell size, supporting the discovery of two extreme life history strategies already described in yeast populations: the "ants," which have lower glycolytic gene dosage, take up glucose slowly, and have a small cell size but reach a high carrying capacity, and the "grasshoppers," which have higher glycolytic gene dosage, consume glucose more rapidly, and allocate it to a larger cell size but reach a lower carrying capacity. These results demonstrate antagonist pleiotropy for glycolytic genes and show that altered dosage of a single gene drives a switch between two life history strategies in yeast.

  14. Streambed microstructure predicts evolution of development and life history mode in the plethodontid salamander Eurycea tynerensis.

    PubMed

    Bonett, Ronald M; Chippindale, Paul T

    2006-03-02

    Habitat variation strongly influences the evolution of developmentally flexible traits, and may drive speciation and diversification. The plethodontid salamander Eurycea tynerensis is endemic to the geologically diverse Ozark Plateau of south-central North America, and comprises both strictly aquatic paedomorphic populations (achieving reproductive maturity while remaining in the larval form) and more terrestrial metamorphic populations. The switch between developmental modes has occurred many times, but populations typically exhibit a single life history mode. This unique system offers an opportunity to study the specific ecological circumstances under which alternate developmental and life history modes evolve. We use phylogenetic independent contrasts to test for relationships between a key microhabitat feature (streambed sediment) and this major life history polymorphism. We find streambed microstructure (sediment particle size, type and degree of sorting) to be highly correlated with life-history mode. Eurycea tynerensis is paedomorphic in streams containing large chert gravel, but metamorphoses in nearby streams containing poorly sorted, clastic material such as sandstone or siltstone. Deposits of large chert gravel create loosely associated streambeds, which provide access to subsurface water during dry summer months. Conversely, streambeds composed of more densely packed sandstone and siltstone sediments leave no subterranean refuge when surface water dries, presumably necessitating metamorphosis and use of terrestrial habitats. This represents a clear example of the relationship between microhabitat structure and evolution of a major developmental and life history trait, and has broad implications for the role of localized ecological conditions on larger-scale evolutionary processes.

  15. Streambed microstructure predicts evolution of development and life history mode in the plethodontid salamander Eurycea tynerensis

    PubMed Central

    Bonett, Ronald M; Chippindale, Paul T

    2006-01-01

    Background Habitat variation strongly influences the evolution of developmentally flexible traits, and may drive speciation and diversification. The plethodontid salamander Eurycea tynerensis is endemic to the geologically diverse Ozark Plateau of south-central North America, and comprises both strictly aquatic paedomorphic populations (achieving reproductive maturity while remaining in the larval form) and more terrestrial metamorphic populations. The switch between developmental modes has occurred many times, but populations typically exhibit a single life history mode. This unique system offers an opportunity to study the specific ecological circumstances under which alternate developmental and life history modes evolve. We use phylogenetic independent contrasts to test for relationships between a key microhabitat feature (streambed sediment) and this major life history polymorphism. Results We find streambed microstructure (sediment particle size, type and degree of sorting) to be highly correlated with life-history mode. Eurycea tynerensis is paedomorphic in streams containing large chert gravel, but metamorphoses in nearby streams containing poorly sorted, clastic material such as sandstone or siltstone. Conclusion Deposits of large chert gravel create loosely associated streambeds, which provide access to subsurface water during dry summer months. Conversely, streambeds composed of more densely packed sandstone and siltstone sediments leave no subterranean refuge when surface water dries, presumably necessitating metamorphosis and use of terrestrial habitats. This represents a clear example of the relationship between microhabitat structure and evolution of a major developmental and life history trait, and has broad implications for the role of localized ecological conditions on larger-scale evolutionary processes. PMID:16512919

  16. Seed after-ripening and dormancy determine adult life history independently of germination timing.

    PubMed

    de Casas, Rafael Rubio; Kovach, Katherine; Dittmar, Emily; Barua, Deepak; Barco, Brenden; Donohue, Kathleen

    2012-05-01

    • Seed dormancy can affect life history through its effects on germination time. Here, we investigate its influence on life history beyond the timing of germination. • We used the response of Arabidopsis thaliana to chilling at the germination and flowering stages to test the following: how seed dormancy affects germination responses to the environment; whether variation in dormancy affects adult phenology independently of germination time; and whether environmental cues experienced by dormant seeds have an effect on adult life history. • Dormancy conditioned the germination response to low temperatures, such that prolonged periods of chilling induced dormancy in nondormant seeds, but stimulated germination in dormant seeds. The alleviation of dormancy through after-ripening was associated with earlier flowering, independent of germination date. Experimental dormancy manipulations showed that prolonged chilling at the seed stage always induced earlier flowering, regardless of seed dormancy. Surprisingly, this effect of seed chilling on flowering time was observed even when low temperatures did not induce germination. • In summary, seed dormancy influences flowering time and hence life history independent of its effects on germination timing. We conclude that the seed stage has a pronounced effect on life history, the influence of which goes well beyond the timing of germination.

  17. Correlative changes in life-history variables in response to environmental change in a model organism.

    PubMed

    Smallegange, Isabel M; Deere, Jacques A; Coulson, Tim

    2014-06-01

    Global change alters the environment, including increases in the frequency of (un)favorable events and shifts in environmental noise color. However, how these changes impact the dynamics of populations, and whether these can be predicted accurately has been largely unexamined. Here we combine recently developed population modeling approaches and theory in stochastic demography to explore how life history, morphology, and average fitness respond to changes in the frequency of favorable environmental conditions and in the color of environmental noise in a model organism (an acarid mite). We predict that different life-history variables respond correlatively to changes in the environment, and we identify different life-history variables, including lifetime reproductive success, as indicators of average fitness and life-history speed across stochastic environments. Depending on the shape of adult survival rate, generation time can be used as an indicator of the response of populations to stochastic change, as in the deterministic case. This work is a useful step toward understanding population dynamics in stochastic environments, including how stochastic change may shape the evolution of life histories.

  18. Maternal thermal environment induces plastic responses in the reproductive life history of oviparous lizards.

    PubMed

    Ma, Liang; Sun, Bao-Jun; Li, Shu-Ran; Sha, Wei; Du, Wei-Guo

    2014-01-01

    Adaptive plasticity may shift phenotypic traits close to a new optimum for directional selection and probably facilitates adaptive evolution in new environments. However, such plasticity has rarely been reported in life-history evolution, despite overwhelming evidence of life-history variation both among and within species. In this study, the temperatures experienced by gravid females of Scincella modesta were manipulated to identify maternally induced plasticity in reproductive traits and the significance of such changes in the evolution of life history. Consistent with the geographic pattern of life history, the study demonstrated that low temperatures delayed egg oviposition, resulting in a more advanced embryonic developmental stage at oviposition and shorter incubation periods compared with warm temperatures. In addition, females maintained at low temperatures produced larger eggs and hence heavier hatchlings than those at warm temperatures. This study demonstrated that environmental temperatures can induce plastic responses in egg retention and offspring size, and these maternally mediated changes in reproductive life history seem to be adaptive in the light of latitudinal clines of these traits in natural populations.

  19. Predicting Life-History Trade-Offs with Whole-Organism Performance.

    PubMed

    Lailvaux, Simon P; Husak, Jerry F

    2017-08-01

    Whole-organism performance traits are key intermediaries between the organism and the environment. Because performance traits are energetically costly to both build and maintain, performance will compete with other life-history traits over a limited pool of acquired energetic resources at any given time, potentially leading to trade-offs in performance expression. Although these trade-offs can have important implications for organismal fitness we currently lack a conceptual framework for predicting both where trade-offs might be expected, and which traits may be especially prone to trade-offs with other fitness-related life-history traits. We propose such a framework based on an estimate of the energetic requirements of locomotion in vertebrates, the ecological cost of transport. By analyzing existing data on mammalian energetic budgets and life-history, we found that species with higher costs of locomotion also tended to be those with "slow" life histories that invest relatively less in current reproduction than "fast" life-history species. We discuss the potential implications of ectothermy for masking such relationships, and how this framework might be expanded upon in the future. © The Author 2017. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology. All rights reserved. For permissions please email: journals.permissions@oup.com.

  20. Life-history variation of a neotropical thrush challenges food limitation theory

    USGS Publications Warehouse

    Ferretti, V.; Llambias, P.E.; Martin, T.E.

    2005-01-01

    Since David Lack first proposed that birds rear as many young as they can nourish, food limitation has been accepted as the primary explanation for variation in clutch size and other life-history traits in birds. The importance of food limitation in life-history variation, however, was recently questioned on theoretical grounds. Here, we show that clutch size differences between two populations of a neotropical thrush were contrary to expectations under Lack's food limitation hypothesis. Larger clutch sizes were found in a population with higher nestling starvation rate (i.e. greater food limitation). We experimentally equalized clutches between populations to verify this difference in food limitation. Our experiment confirmed greater food limitation in the population with larger mean clutch size. In addition, incubation bout length and nestling growth rate were also contrary to predictions of food limitation theory. Our results demonstrate the inability of food limitation to explain differences in several life-history traits: clutch size, incubation behaviour, parental feeding rate and nestling growth rate. These life-history traits were better explained by inter-population differences in nest predation rates. Food limitation may be less important to life history evolution in birds than suggested by traditional theory. ?? 2005 The Royal Society.

  1. Variation in reproductive life history traits between two populations of Blackbanded Darters (Percina nigrofasciata)

    USGS Publications Warehouse

    Hughey, Myra C.; Heins, David C.; Jelks, Howard L.; Ory, Bridget A.; Jordan, Frank

    2012-01-01

    We examined the life history of Blackbanded Darters (Percina nigrofasciata) from two streams in the Choctawhatchee River drainage, Florida, over a three-year study period. Blackbanded Darters from Turkey Creek were longer than fish from Ten Mile Creek; however, size-adjusted clutch and egg sizes were similar between populations. Larger females produced larger clutches, whereas egg size did not vary with female body size. Seasonally, clutch sizes were greater in May than in August. When contrasted with previous studies of Blackbanded Darters in Alabama and Louisiana, the reproductive season of Blackbanded Darters in Florida was unusually long, ceasing for only a few months in late fall. The reproductive season was longer in Turkey Creek than in Ten Mile Creek. Differences in thermal regime among streams may explain differences in life history traits among local and distant populations of Blackbanded Darters. This research, alone and in combination with previous studies of this species, emphasizes two main points. First, it reaffirms that life history studies based on a single locality or conducted at a single point in time may fail to capture the full range of variation in life history traits. Second, it highlights the extensive phenotypic variation found in species with broad geographic ranges. Such species lend themselves to comparative and experimental research on patterns and causes of life history variation.

  2. Shifts in the life history of parasitic wasps correlate with pronounced alterations in early development.

    PubMed

    Grbić, M; Strand, M R

    1998-02-03

    Developmental processes have been traditionally viewed to be invariant within higher taxa. However, examples are known whereby closely related species exhibit alterations in early embryogenesis yet appear very similar as adults. Such developmental changes are thought to occur in response to shifts in life history. In insects, the regulation of embryonic development has been intensively studied in model species like Drosophila melanogaster. Previous comparative studies suggest that the developmental processes documented in Drosophila well describe embryogenesis of advanced, holometabolous, insects generally. There have been few attempts, however, to take into account how life history has influenced early development of insects or to characterize early development of species with life histories fundamentally different from flies. Here we compared early development of two species from the same family of parasitic wasps that exhibit very different life histories. Bracon hebetor is an ectoparasite that lays large, yolky eggs on the integument of its host that develop much like the free-living honeybee and Drosophila. In contrast, Aphidius ervi is an endoparasite that lays small and apparently yolk-free eggs that develop in the hemocoel of the host. This wasp exhibits a radically different mode of early development at both the cellular and molecular level from B. hebetor. The developmental changes in A. ervi reflect functional adaptations for its derived life history and argue that departures from the fly paradigm may occur commonly among insects whose eggs develop under conditions different from typical terrestrial species.

  3. Shifts in the life history of parasitic wasps correlate with pronounced alterations in early development

    PubMed Central

    Grbic, Miodrag; Strand, Michael R.

    1998-01-01

    Developmental processes have been traditionally viewed to be invariant within higher taxa. However, examples are known whereby closely related species exhibit alterations in early embryogenesis yet appear very similar as adults. Such developmental changes are thought to occur in response to shifts in life history. In insects, the regulation of embryonic development has been intensively studied in model species like Drosophila melanogaster. Previous comparative studies suggest that the developmental processes documented in Drosophila well describe embryogenesis of advanced, holometabolous, insects generally. There have been few attempts, however, to take into account how life history has influenced early development of insects or to characterize early development of species with life histories fundamentally different from flies. Here we compared early development of two species from the same family of parasitic wasps that exhibit very different life histories. Bracon hebetor is an ectoparasite that lays large, yolky eggs on the integument of its host that develop much like the free-living honeybee and Drosophila. In contrast, Aphidius ervi is an endoparasite that lays small and apparently yolk-free eggs that develop in the hemocoel of the host. This wasp exhibits a radically different mode of early development at both the cellular and molecular level from B. hebetor. The developmental changes in A. ervi reflect functional adaptations for its derived life history and argue that departures from the fly paradigm may occur commonly among insects whose eggs develop under conditions different from typical terrestrial species. PMID:9448291

  4. Time constraints mediate predator-induced plasticity in immune function, condition, and life history.

    PubMed

    Stoks, Robby; De Block, Marjan; Slos, Stefanie; Van Doorslaer, Wendy; Rolff, Jens

    2006-04-01

    The simultaneous presence of predators and a limited time for development imposes a conflict: accelerating growth under time constraints comes at the cost of higher predation risk mediated by increased foraging. The few studies that have addressed this tradeoff have dealt only with life history traits such as age and size at maturity. Physiological traits have largely been ignored in studies assessing the impact of environmental stressors, and it is largely unknown whether they respond independently of life history traits. Here, we studied the simultaneous effects of time constraints, i.e., as imposed by seasonality, and predation risk on immune defense, energy storage, and life history in lestid damselflies. As predicted by theory, larvae accelerated growth and development under time constraints while the opposite occurred under predation risk. The activity of phenoloxidase, an important component of insect immunity, and investment in fat storage were reduced both under time constraints and in the presence of predators. These reductions were smaller when time constraints and predation risk were combined. This indicates that predators can induce sublethal costs linked to both life history and physiology in their prey, and that time constraints can independently reduce the impact of predator-induced changes in life history and physiology.

  5. End of Life Decisions for Sealed Radioactive Sources.

    PubMed

    Pryor, Kathryn H

    2016-02-01

    Sealed radioactive sources are encountered in a wide variety of settings-from household smoke detectors and instrument check sources through fixed industrial gauges, industrial radiography, and well logging sources, to irradiators and medical teletherapy devices. In general, the higher the level of activity in the sealed source, the stricter the regulatory control that is applied to its use, control, and ultimate disposition. Lower levels of attention and oversight can and do lead to sources ending up in the wrong place--as orphan sources in uncontrolled storage, disposed in a sanitary landfill, melted down in metal recycling operations and incorporated into consumer products, or handled by an unsuspecting member of the public. There is a range of issues that contribute to the problem of improper disposal of sealed sources and, in particular, to disused source disposal. Generally licensed sources and devices are particularly at risk of being disposed incorrectly. Higher activity generally licensed sources, although required to be registered with the (NRC) or an Agreement State, receive limited regulatory oversight and are not tracked on a national scale. Users frequently do not consider the full life-cycle costs when procuring sources or devices and discover that they cannot afford and/or are unwilling to pay the associated costs to package, transport and dispose of their sources properly. The NRC requirements for decommissioning funding plans and financial assurance are not adequate to cover sealed source transport and disposal costs fully. While there are regulatory limits for storage of disused sources, enforcement is limited, and there are only limited financial incentives in a small number of states for owners to dispose of the sources. In some cases, the lack of availability of approved Type B shipping casks presents an additional barrier to sealed source disposal. The report of the Disused Sources Working Group does an excellent job of framing these issues

  6. Predicting responses to climate change requires all life-history stages.

    PubMed

    Zeigler, Sara

    2013-01-01

    In Focus: Radchuk, V., Turlure, C. & Schtickzelle, N. (2013) Each life stage matters: the importance of assessing response to climate change over the complete life cycle in butterflies. Journal of Animal Ecology, 82, 275-285. Population-level responses to climate change depend on many factors, including unexpected interactions among life history attributes; however, few studies examine climate change impacts over complete life cycles of focal species. Radchuk, Turlure & Schtickzelle () used experimental and modelling approaches to predict population dynamics for the bog fritillary butterfly under warming scenarios. Although they found that warming improved fertility and survival of all stages with one exception, populations were predicted to decline because overwintering larvae, whose survival declined with warming, were disproportionately important contributors to population growth. This underscores the importance of considering all life history stages in analyses of climate change's effects on population dynamics.

  7. Ethics at the end of life: who should make decisions about treatment limitation for young children with life-threatening or life-limiting conditions?

    PubMed

    Gillam, Lynn; Sullivan, Jane

    2011-09-01

    It is now ethical orthodoxy that parents should be involved in the decision-making about their children's health care. This extends to decisions about whether to continue or to limit life-sustaining medical treatment for a child with a life-limiting or life-threatening condition. What remains contested and uncertain is the extent and nature of parental involvement, especially in this emotionally charged situation. In particular, should it be the parents, who are the ultimate decision-makers, taking final responsibility, should it be a shared decision, or should it be a medical decision that parents are simply asked to consent to? One approach to this issue is to consider the in-principle ethical arguments and weigh their merits. The two key principles here are parental rights and authority, and the best interests of child, and the contested issue is what to do if these appear to clash. Another approach is to consider the principles in the practical clinical context. What would be the implications and consequences of adopting the model of parents as final decision-makers? Are parents able to carry out this role, and do they really want it? What is the effect on parents of taking this role? Answers to these questions could modify the in-principle ethical position. In this paper, we review the empirical evidence currently available on these questions, in relation to parents of infants and young children. Overall, the literature suggests that parents do want to be involved and do not suffer adverse psychological consequences from their involvement. However, the crucial ethical implication of the evidence is that the level and nature of parental involvement in decision-making should be negotiated with the parents in each case, because parents have a range of different views about taking final responsibility for decisions. © 2011 The Authors. Journal of Paediatrics and Child Health © 2011 Paediatrics and Child Health Division (Royal Australasian College of Physicians).

  8. Life-history evolution and the microevolution of intermediary metabolism: activities of lipid-metabolizing enzymes in life-history morphs of a wing-dimorphic cricket.

    PubMed

    Zera, Anthony J; Zhao, Zhangwu

    2003-03-01

    Although a considerable amount of information is available on the ecology, genetics, and physiology of life-history traits, much more limited data are available on the biochemical and genetic correlates of life-history variation within species. Specific activities of five enzymes of lipid biosynthesis and two enzymes of amino acid catabolism were compared among lines selected for flight-capable (LW[f]) versus flightless (SW) morphs of the cricket Gryllus firmus. These morphs, which exist in natural populations, differ genetically in ovarian growth (100-400% higher in SW) and aspects of flight capability including the size of wings and flight muscles, and the concentration of triglyceride flight fuel (40% greater in LW[f]). Consistently higher activity of each enzyme in LW(f) versus SW-selected lines, and strong co-segregation between morph and enzyme activity, demonstrated genetically based co-variance between wing morph and enzyme activity. Developmental profiles of enzyme activities strongly paralleled profiles of triglyceride accumulation during adulthood and previous measures of in vivo lipid biosynthesis. These data strongly imply that genetically based elevation in activities of lipogenic enzymes, and enzymes controlling the conversion of amino acids into lipids, is an important cause underlying the elevated accumulation of triglyceride in the LW(f) morph, a key biochemical component of the trade-off between elevated early fecundity and flight capability. Global changes in lipid and amino-acid metabolism appear to have resulted from microevolutionary alteration of regulators of metabolism. Finally, strong genotype x environment (diet) interactions were observed for most enzyme activities. Future progress in understanding the functional causes of life-history evolution requires a more detailed synthesis of the fields of life-history evolution and metabolic biochemistry. Wing polymorphism is a powerful experimental model in such integrative studies.

  9. The life histories of American stepfathers in evolutionary perspective.

    PubMed

    Anderson, K G

    2000-12-01

    This paper presents an analysis of the characteristics of men who become stepfathers, and their subsequent fertility patterns and lifetime reproductive success. Because women who already have children are ranked lower in the marriage market than women without children, men who marry women with children (e.g., stepfathers) are likely to have lower rankings in the marriage market as well. Using retrospective fertility and marital histories from the Panel Study of Income Dynamics (PSID), I show that men who become stepfathers have lower levels of education, less income, and are more likely to have been divorced before and to already have children, all characteristics that lower their rankings in the marriage market. Men with one or two stepchildren are just as likely to have children within a marriage as non-stepfathers, although men with three stepchildren show decreased fertility. Among men age 45 and older, stepfathers have lower lifetime fertility than non-stepfathers, although the difference disappears when men's age at first marriage is controlled for. Additionally, stepfathers have significantly higher fertility than men who never marry. The results suggest that some men become stepfathers to procure mates and fertility benefits that they would otherwise have been unlikely to obtain; for these men, raising other men's children serves as a form of mating effort.

  10. Fast–slow continuum and reproductive strategies structure plant life-history variation worldwide

    PubMed Central

    Salguero-Gómez, Roberto; Jones, Owen R.; Jongejans, Eelke; Blomberg, Simon P.; Hodgson, David J.; Mbeau-Ache, Cyril; Zuidema, Pieter A.; de Kroon, Hans; Buckley, Yvonne M.

    2016-01-01

    The identification of patterns in life-history strategies across the tree of life is essential to our prediction of population persistence, extinction, and diversification. Plants exhibit a wide range of patterns of longevity, growth, and r