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. 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

    2015-05-01

    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

  3. 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

  4. 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

  5. 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…

  6. 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.

  7. 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

  8. 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

  9. Diffusion Decision Model: Current Issues and History.

    PubMed

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

    2016-04-01

    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 review, we relate the models to both earlier and more recent research in psychology. PMID:26952739

  10. The Evolution of Transfers and Life Histories

    PubMed Central

    Cyrus, C. Y.

    2012-01-01

    Much of life history theory analyzes life histories of independent, isolated individuals, who grow, forage, reproduce, and die. However, in many species social interactions such as food sharing are a key part of the life history strategy, altering the energetic budget constraint. Transfers and sharing raise reproductive success and also alter the fitness impact of other aspects of the life history. We discuss a variety of traits and behaviors for which transfers are important, synthesizing results from a number of earlier papers. Topics include the U-shaped mortality curve, post reproductive survival, causes of early life mortality decline, why intergenerational transfers evolve and co-evolve with longevity, time preference, sexual dimorphism and sexual differences in transfers, menopause, demographic advantages of social sharing, and consequences of social sharing for life history evolution. PMID:22750486

  11. 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.

  12. 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…

  13. A brief history of decision making.

    PubMed

    Buchanan, Leigh; O'Connell, Andrew

    2006-01-01

    Sometime around the middle of the past century, telephone executive Chester Barnard imported the term decision making from public administration into the business world. There it began to replace narrower terms, like "resource allocation" and "policy making," shifting the way managers thought about their role from continuous, Hamlet-like deliberation toward a crisp series of conclusions reached and actions taken. Yet, decision making is, of course, a broad and ancient human pursuit, flowing back to a time when people sought guidance from the stars. From those earliest days, we have strived to invent better tools for the purpose, from the Hindu-Arabic systems for numbering and algebra, to Aristotle's systematic empiricism, to friar Occam's advances in logic, to Francis Bacon's inductive reasoning, to Descartes's application of the scientific method. A growing sophistication with managing risk, along with a nuanced understanding of human behavior and advances in technology that support and mimic cognitive processes, has improved decision making in many situations. Even so, the history of decision-making strategies--captured in this time line and examined in the four accompanying essays on risk, group dynamics, technology, and instinct--has not marched steadily toward perfect rationalism. Twentieth-century theorists showed that the costs of acquiring information lead executives to make do with only good-enough decisions. Worse, people decide against their own economic interests even when they know better. And in the absence of emotion, it's impossible to make any decisions at all. Erroneous framing, bounded awareness, excessive optimism: The debunking of Descartes's rational man threatens to swamp our confidence in our choices. Is it really surprising, then, that even as technology dramatically increases our access to information, Malcolm Gladwell extols the virtues of gut decisions made, literally, in the blink of an eye? PMID:16447367

  14. 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…

  15. Adaptable history biases in human perceptual decisions.

    PubMed

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

    2016-06-21

    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

  16. 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. PMID:23117406

  17. 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.

  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. Life history diversity in Klamath River steelhead

    USGS Publications Warehouse

    Hodge, Brian W.; Wilzbach, Peggy; Duffy, Walter G. 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

  20. 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

  1. 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. PMID:26267241

  2. 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

  3. 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

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

    PubMed

    Stearns, S C

    2000-11-01

    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. PMID:11151666

  5. 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, ...

  6. 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

  7. 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. PMID:22289411

  8. 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

  9. Grandmothering life histories and human pair bonding.

    PubMed

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

    2015-09-22

    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

  10. 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…

  11. 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)

  12. 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". PMID:11541730

  13. Hansen's Oral Life Histories and Healing.

    PubMed

    Kim, Seong-Lee

    2013-08-01

    The individual oral statement is human story based on experience. The personal experience forms unconsciousness which appears in a form of oral statement by ego that doesn't want to lose existence. Thus, the process which exposes a tormented hearts is the objectification of oneself. Through this step, oral person attains a healing. If this sort of individual oral is accrued, the undeserved personal affairs could be a history. In case of Hansen's disease patient, She could escape from negative understanding about herself and the world. Furthermore, She kept formating her values about meaningful life and future oriented value. Also, She wants to keep a record of her life. She comes to know that what she denied is actually what she should surmount over oral statement. As a result, She could attains a healing for oneself through oral statement. The oral statement made her look into she's problems. Therefore, oral statement is a self-realization. Through this, person could know what the problem is and solution. This research is about only one person, so there is need for more cases and studies. If this sort of individual oral statement is accrued, there could be a curative narration. This can suggest an curative alternative when we suffer from problem of life. The merit of this research is rendering this possibility. PMID:24005645

  14. 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

  15. 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. PMID:26114642

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

    PubMed

    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

  17. 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

  18. 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. PMID:26315435

  19. Video May Aid End-of-Life Decision-Making

    MedlinePlus

    ... fullstory_159659.html Video May Aid End-of-Life Decision-Making Brief film helped heart failure patients ... HealthDay News) -- Watching a video about end-of-life care options may help patients with advanced heart ...

  20. Evolution of life history variation among female mammals.

    PubMed Central

    Charnov, E L

    1991-01-01

    A unified approach is developed for the evolutionary structure of mammalian life histories; it blends together three basic components (individual growth or production rate as a function of body size, natural selection on age of maturity, and stable demography) to predict both the powers and the intercepts of the scaling allometry of life history variables to adult size. The theory also predicts the signs (+, -) of the correlations between life history variables when body size is held constant. Finally, the approach allows us to eliminate body size to predict the dimensionless relationships between the life history variables themselves. PMID:1996315

  1. 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

  2. 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. PMID:23907657

  3. Life history consequences of mammal sibling rivalry.

    PubMed

    Stockley, P; Parker, G A

    2002-10-01

    Mammal life history traits relating to growth and reproduction are extremely diverse. Sibling rivalry may contribute to selection pressures influencing this diversity, because individuals that are relatively large at birth typically have an advantage in competition for milk. However, selection for increased growth rate is likely to be constrained by kin selection and physiological costs. Here, we present and test a model examining the ESS (evolutionarily stable strategy) balance between these constraints and advantages associated with increased prenatal growth in mammal sibling rivalry. Predictions of the model are supported by results of comparative analyses for the Carnivora and Insectivora, which demonstrate an increase in prenatal growth rate with increasing intensity of postnatal scramble competition, and a decrease in postnatal growth rate relative to size at birth. Because increased prenatal growth rates are predicted to select for reduced gestation length under certain conditions, our study also indicates that sibling rivalry may contribute to selection pressures influencing variation in altriciality and precociality among mammals. PMID:12237403

  4. Evolution of alternative insect life histories in stochastic seasonal environments.

    PubMed

    Kivelä, Sami M; Välimäki, Panu; Gotthard, Karl

    2016-08-01

    Deterministic seasonality can explain the evolution of alternative life history phenotypes (i.e., life history polyphenism) expressed in different generations emerging within the same year. However, the influence of stochastic variation on the expression of such life history polyphenisms in seasonal environments is insufficiently understood. Here, we use insects as a model and explore (1) the effects of stochastic variation in seasonality and (2) the life cycle on the degree of life history differentiation among the alternative developmental pathways of direct development and diapause (overwintering), and (3) the evolution of phenology. With numerical simulation, we determine the values of development (growth) time, growth rate, body size, reproductive effort, adult life span, and fecundity in both the overwintering and directly developing generations that maximize geometric mean fitness. The results suggest that natural selection favors the expression of alternative life histories in the alternative developmental pathways even when there is stochastic variation in seasonality, but that trait differentiation is affected by the developmental stage that overwinters. Increasing environmental unpredictability induced a switch to a bet-hedging type of life history strategy, which is consistent with general life history theory. Bet-hedging appeared in our study system as reduced expression of the direct development phenotype, with associated changes in life history phenotypes, because the fitness value of direct development is highly variable in uncertain environments. Our main result is that seasonality itself is a key factor promoting the evolution of seasonally polyphenic life histories but that environmental stochasticity may modulate the expression of life history phenotypes. PMID:27547340

  5. Strength of density feedback in census data increases from slow to fast life histories

    PubMed Central

    Herrando-Pérez, Salvador; Delean, Steven; Brook, Barry W; Bradshaw, Corey J A

    2012-01-01

    Life-history theory predicts an increasing rate of population growth among species arranged along a continuum from slow to fast life histories. We examine the effects of this continuum on density-feedback strength estimated using long-term census data from >700 vertebrates, invertebrates, and plants. Four life-history traits (Age at first reproduction, Body size, Fertility, Longevity) were related statistically to Gompertz strength of density feedback using generalized linear mixed-effects models and multi-model inference. Life-history traits alone explained 10 to 30% of the variation in strength across species (after controlling for time-series length and phylogenetic nonindependence). Effect sizes were largest for body size in mammals and longevity in birds, and density feedback was consistently stronger for smaller-bodied and shorter-lived species. Overcompensatory density feedback (strength <−1) occurred in 20% of species, predominantly at the fast end of the life-history continuum, implying relatively high population variability. These results support the idea that life history leaves an evolutionary signal in long-term population trends as inferred from census data. Where there is a lack of detailed demographic data, broad life-history information can inform management and conservation decisions about rebound capacity from low numbers, and propensity to fluctuate, of arrays of species in areas planned for development, harvesting, protection, and population recovery. PMID:22957193

  6. Observations on the Life History of Small Hive Beetles

    Technology Transfer Automated Retrieval System (TEKTRAN)

    DeGuzman, L.I.& A.M. Frake. Observations on the Life History of Small Hive Beetles - The life history of small hive beetles (SHB) kept in an incubator (34ºC) and at room temperature (24-28ºC) was compared. Six slides of eggs, obtained using the glass slide technique, were placed individually in rear...

  7. 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…

  8. 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…

  9. 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 method in the…

  10. 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 research…

  11. Lives in Context: The Art of Life History Research.

    ERIC Educational Resources Information Center

    Cole, Ardra L., Ed.; Knowles, J. Gary, Ed.

    The reflexive turn in qualitative research has transformed the process of doing life history research. No longer are research subjects examined through the lens of the all-knowing but supposedly invisible researcher. According to this book, an introduction to conducting life history research, the process is now one of mutuality, empathy,…

  12. When success breeds failure: history, hysteresis, and delayed exit decisions.

    PubMed

    Bragger, Jennifer DeNicolis; Hantula, Donald A; Bragger, Donald; Kirnan, Jean; Kutcher, Eugene

    2003-02-01

    The effects of feedback equivocality, information availability, and prior decision-making history on escalation and persistence were investigated. Replicating the findings of J.L. Bragger, D.H. Bragger, D.A. Hantula, and J.P. Kirnan (1998), this study found that participants receiving equivocal feedback on their decisions invested more money and invested across more opportunities; those who could purchase information invested fewer resources than did participants who did not have the opportunity to purchase information. There was an inverse linear relationship between the percentage of opportunities in which participants purchased information and the delay to exit decisions and total resources invested. Six weeks earlier, some participants took part in a more profitable investment scenario, and prior experience led to later increased investing when participants were faced with failure, even above that invested in a preceding, succeeding scenario. These results are consistent with an equivocality theory account of escalation. PMID:12675390

  13. 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.…

  14. 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

  15. Guardianship and End-of-Life Decision Making.

    PubMed

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

    2015-10-01

    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 official has no preexisting 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. Physicians 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. However, physicians 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 to characterize the authority of a guardian over choices about end-of-life treatment. We found that most state guardianship statutes have no language about end-of-life decisions. We identified 5 legal cases during the past decade that addressed a guardian's authority over these decisions, and only 1 case provided a broad framework applicable to clinical practice. Work to improve end-of-life decision making by guardians may benefit from a multidisciplinary effort to develop comprehensive standards to guide clinicians and guardians when treatment decisions need to be made. PMID:26258634

  16. 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…

  17. Oxidative stress and life histories: unresolved issues and current needs.

    PubMed

    Speakman, John R; Blount, Jonathan D; Bronikowski, Anne M; Buffenstein, Rochelle; Isaksson, Caroline; Kirkwood, Tom B L; Monaghan, Pat; Ozanne, Susan E; Beaulieu, Michaël; Briga, Michael; Carr, Sarah K; Christensen, Louise L; Cochemé, Helena M; Cram, Dominic L; Dantzer, Ben; Harper, Jim M; Jurk, Diana; King, Annette; Noguera, Jose C; Salin, Karine; Sild, Elin; Simons, Mirre J P; Smith, Shona; Stier, Antoine; Tobler, Michael; Vitikainen, Emma; Peaker, Malcolm; Selman, Colin

    2015-12-01

    Life-history theory concerns the trade-offs that mold the patterns of investment by animals between reproduction, growth, and survival. It is widely recognized that physiology plays a role in the mediation of life-history trade-offs, but the details remain obscure. As life-history theory concerns aspects of investment in the soma that influence survival, understanding the physiological basis of life histories is related, but not identical, to understanding the process of aging. One idea from the field of aging that has gained considerable traction in the area of life histories is that life-history trade-offs may be mediated by free radical production and oxidative stress. We outline here developments in this field and summarize a number of important unresolved issues that may guide future research efforts. The issues are as follows. First, different tissues and macromolecular targets of oxidative stress respond differently during reproduction. The functional significance of these changes, however, remains uncertain. Consequently there is a need for studies that link oxidative stress measurements to functional outcomes, such as survival. Second, measurements of oxidative stress are often highly invasive or terminal. Terminal studies of oxidative stress in wild animals, where detailed life-history information is available, cannot generally be performed without compromising the aims of the studies that generated the life-history data. There is a need therefore for novel non-invasive measurements of multi-tissue oxidative stress. Third, laboratory studies provide unrivaled opportunities for experimental manipulation but may fail to expose the physiology underpinning life-history effects, because of the benign laboratory environment. Fourth, the idea that oxidative stress might underlie life-history trade-offs does not make specific enough predictions that are amenable to testing. Moreover, there is a paucity of good alternative theoretical models on which contrasting

  18. The illusion of invariant quantities in life histories.

    PubMed

    Nee, Sean; Colegrave, Nick; West, Stuart A; Grafen, Alan

    2005-08-19

    Life-history theory attempts to provide evolutionary explanations for variations in the ways in which animal species live their lives. Recent analyses have suggested that the dimensionless ratios of several key life-history parameters are the same for different species, even across distant taxa. However, we show here that previous analyses may have given a false picture and created an illusion of invariants, which do not necessarily exist; essentially, this is because life-history variables have been regressed against themselves. The following question arises from our analysis: How do we identify an invariant? PMID:16109879

  19. 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.

  20. LIFE HISTORY OF DELPHASTUS CATALINAE: A PREDATOR OF BEMISIA ARGENTIFOLII

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Immature development and reproductive life history of Delphastus catalinae (Coleoptera: Coccinellidae) feeding on Bemisia argentifolii (Homoptera: Aleyrodidae) immatures was studied at three constant temperatures: 22, 26 and 30 ºC. Development rates and lower temperature threshold temperatures (T0) ...

  1. 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. PMID:21672739

  2. Early life history: A computer analysis

    NASA Astrophysics Data System (ADS)

    Bell, Peter M.

    Theoretical computer calculations, based in part on measurements of ‘young’ stars obtained with an orbiting telescope, may require a reexamination of some of the basic ideas about the composition of the earth's early atmosphere and the origin of life. According to Joel S. Levine, atmospheric geophysicist at the Langley Research Center, ‘the overwhelming majority of chemical evolution experiments since the first in 1952 may have been conducted with the wrong atmospheric mixture.’Astronomical measurements indicate that considerably more ultraviolet (UV) radiation may have been emitted by the young sun in comparison to that emitted by the present sun. Therefore, high levels of such radiation from the young sun, potentially harmful to life, would have been striking the earth at the very time life was being formed.Recent photochemical calculations by Levine and others at Langley state that at the time complex organic molecules (the precursors of living systems) were first formed from atmospheric gases the earth's atmosphere was not composed primarily of methane, ammonia, and hydrogen, as was previously supposed; instead, it was composed of carbon dioxide, nitrogen, and water vapor, all resulting from volcanic activity. The calculations indicate that both methane and ammonia were extremely short-lived and that such an atmosphere was photochemically unstable if it existed at all.

  3. The digital life history project: intergenerational collaborative research.

    PubMed

    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. The resulting multimedia videos are then screened for the community at large at the end of the semester. Students and elders alike report long-term personal, interpersonal, and community-based effects from participating in the Digital Life History Project, including making meaningful relationships, linking biography and history, learning to confront ageism, charting the next chapter, and participating in community-wide education. PMID:23362853

  4. 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

  5. Projection in surrogate decisions about life-sustaining medical treatments.

    PubMed

    Fagerlin, A; Ditto, P H; Danks, J H; Houts, R M; Smucker, W D

    2001-05-01

    To honor the wishes of an incapacitated patient, surrogate decision makers must predict the treatment decisions patients would make for themselves if able. Social psychological research, however, suggests that surrogates' own treatment preferences may influence their predictions of others' preferences. In 2 studies (1 involving 60 college student surrogates and a parent, the other involving 361 elderly outpatients and their chosen surrogate decision maker), surrogates predicted whether a close other would want life-sustaining treatment in hypothetical end-of-life scenarios and stated their own treatment preferences in the same scenarios. Surrogate predictions more closely resembled surrogates' own treatment wishes than they did the wishes of the individual they were trying to predict. Although the majority of prediction errors reflected inaccurate use of surrogates' own treatment preferences, projection was also found to result in accurate prediction more often than counterprojective predictions. The rationality and accuracy of projection in surrogate decision making is discussed. PMID:11403214

  6. 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. PMID:27172590

  7. Nutrition shapes life-history evolution across species.

    PubMed

    Swanson, Eli M; Espeset, Anne; Mikati, Ihab; Bolduc, Isaac; Kulhanek, Robert; White, William A; Kenzie, Susan; Snell-Rood, Emilie C

    2016-07-13

    Nutrition is a key component of life-history theory, yet we know little about how diet quality shapes life-history evolution across species. Here, we test whether quantitative measures of nutrition are linked to life-history evolution across 96 species of butterflies representing over 50 independent diet shifts. We find that butterflies feeding on high nitrogen host plants as larvae are more fecund, but their eggs are smaller relative to their body size. Nitrogen and sodium content of host plants are also both positively related to eye size. Some of these relationships show pronounced lineage-specific effects. Testis size is not related to nutrition. Additionally, the evolutionary timing of diet shifts is not important, suggesting that nutrition affects life histories regardless of the length of time a species has been adapting to its diet. Our results suggest that, at least for some lineages, species with higher nutrient diets can invest in a range of fitness-related traits like fecundity and eye size while allocating less to each egg as offspring have access to a richer diet. These results have important implications for the evolution of life histories in the face of anthropogenic changes in nutrient availability. PMID:27412282

  8. Life history trade-offs in tropical trees and lianas.

    PubMed

    Gilbert, Benjamin; Wright, S Joseph; Muller-Landau, Helene C; Kitajima, Kaoru; Hernandéz, Andrés

    2006-05-01

    It has been hypothesized that tropical trees partition forest light environments through a life history trade-off between juvenile growth and survival; however, the generality of this trade-off across life stages and functional groups has been questioned. We quantified trade-offs between growth and survival for trees and lianas on Barro Colorado Island (BCI), Panama using first-year seedlings of 22 liana and 31 tree species and saplings (10 mm < dbh < 39 mm) of 30 tree species. Lianas showed trade-offs similar to those of trees, with both groups exhibiting broadly overlapping ranges in survival and relative growth rates as seedlings. Life history strategies at the seedling stage were highly correlated with those at the sapling stage among tree species, with all species showing an increase in survival with size. Only one of 30 tree species demonstrated a statistically significant ontogenetic shift, having a relatively lower survival rate at the sapling stage than expected. Our results indicate that similar life history trade-offs apply across two functional groups (lianas and trees), and that life history strategies are largely conserved across seedling and sapling life-stages for most tropical tree species. PMID:16761606

  9. Accuracy of a Decision Aid for Advance Care Planning: Simulated End-of-Life Decision Making

    PubMed Central

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

    2013-01-01

    Purpose 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. Methods 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. Results 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). Conclusion 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. PMID:22167985

  10. Making a difference in end-of-life decisions.

    PubMed

    Danko, Helen

    2004-01-01

    In summary, this process is painful for family and caregivers, particularly after an extended relationship as the one experienced above. It requires a strong commitment on the part of the health care team who embrace a dignified end-of-life process and the decisions that must be made. The health care team that cared so well for S.R. in life was able to assist and be part of his dignified closure. PMID:15453241

  11. Primate molar crown formation times and life history evolution revisited.

    PubMed

    Macho, G A

    2001-12-01

    Comparative studies have convincingly demonstrated that the pattern and timing of tooth emergence are highly correlated with life-history variables and brain size. Conversely, a firm relationship between molar formation time and life-history variables has not yet been established. It seems counterintuitive that one aspect of dental development should be correlated with life-history variables, whereas the other should not. In order to shed light on this apparent discrepancy this study analyzed all data on primate molar crown formations available in the published literature in relation to life-history variables, brain size, and female body mass. Crown formation times were found to be particularly highly correlated with both female body mass and brain size. Species that depart from the overall brain/body allometry by being relatively large-bodied, e.g., Gorilla gorilla and later Theropithecus oswaldi, also have shorter molar crown formation times than expected. The reverse is not found for species that depart from the overall brain/body allometry due to their larger brains, i.e., Homo sapiens. This finding is interpreted within an evolutionary and ecological framework. Specifically, by focusing on ecological commonalities, a scenario is proposed which may allow predictions to be made about the evolutionary history of other extinct primates also. If confirmed in future studies, crown formation time may again become a powerful tool in evolutionary enquiry. PMID:11748692

  12. 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. PMID:27429777

  13. Ecdysteroid hormones link the juvenile environment to alternative adult life histories in a seasonal insect.

    PubMed

    Oostra, Vicencio; Mateus, Ana Rita A; van der Burg, Karin R L; Piessens, Thomas; van Eijk, Marleen; Brakefield, Paul M; Beldade, Patrícia; Zwaan, Bas J

    2014-09-01

    The conditional expression of alternative life strategies is a widespread feature of animal life and a pivotal adaptation to life in seasonal environments. To optimally match suites of traits to seasonally changing ecological opportunities, animals living in seasonal environments need mechanisms linking information on environmental quality to resource allocation decisions. The butterfly Bicyclus anynana expresses alternative adult life histories in the alternating wet and dry seasons of its habitat as endpoints of divergent developmental pathways triggered by seasonal variation in preadult temperature. Pupal ecdysteroid hormone titers are correlated with the seasonal environment, but whether they play a functional role in coordinating the coupling of adult traits in the alternative life histories is unknown. Here, we show that manipulating pupal ecdysteroid levels is sufficient to mimic in direction and magnitude the shifts in adult reproductive resource allocation normally induced by seasonal temperature. Crucially, this allocation shift is accompanied by changes in ecologically relevant traits, including timing of reproduction, life span, and starvation resistance. Together, our results support a functional role for ecdysteroids during development in mediating strategic reproductive investment decisions in response to predictive indicators of environmental quality. This study provides a physiological mechanism for adaptive developmental plasticity, allowing organisms to cope with variable environments. PMID:25141151

  14. 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. PMID:26047544

  15. Decision analysis as a life support technology assessment capability.

    PubMed

    Ballin, M G

    1995-01-01

    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, especially in a resource-constrained environment. In the application of life support technology to future manned space flight, new technology concepts typically are characterized by 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 confronting a decision maker. It also accounts for the limits of knowledge 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 useful insight for making technology development resource allocation decisions. PMID:11538570

  16. 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.

  17. Novelty and Innovation in the History of Life.

    PubMed

    Erwin, Douglas H

    2015-10-01

    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. PMID:26439356

  18. 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.

  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. Theorising Learning in Life History: A Psychosocietal Approach

    ERIC Educational Resources Information Center

    Olesen, Henning Salling

    2007-01-01

    Taking its point of departure from some critical remarks about some of the most important recent theorising of learning, this article presents an alternative framework for theorising learning as a subjective process in a social and societal context, based on life history research. The key concepts of subjectivity and experience, derived from…

  1. Life History of Delphastus Catalinae: a predator of Bemisia tabaci

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Immature development and reproductive life history of Delphastus catalinae (Coleoptera: Coccinellidae) feeding on Bemisia tabaci (Homoptera: Aleyrodidae) immatures was studied at three constant temperatures: 22, 26 and 30 ºC. Development rates and lower temperature threshold temperatures (T0) were e...

  2. 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. PMID:24556439

  3. 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. PMID:24690406

  4. 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,…

  5. 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. PMID:25992637

  6. 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. PMID:17152604

  7. 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…

  8. 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.

  9. Towards cancer-aware life-history modelling.

    PubMed

    Kokko, Hanna; Hochberg, Michael E

    2015-07-19

    Studies of body size evolution, and life-history theory in general, are conducted without taking into account cancer as a factor that can end an organism's reproductive lifespan. This reflects a tacit assumption that predation, parasitism and starvation are of overriding importance in the wild. We argue here that even if deaths directly attributable to cancer are a rarity in studies of natural populations, it remains incorrect to infer that cancer has not been of importance in shaping observed life histories. We present first steps towards a cancer-aware life-history theory, by quantifying the decrease in the length of the expected reproductively active lifespan that follows from an attempt to grow larger than conspecific competitors. If all else is equal, a larger organism is more likely to develop cancer, but, importantly, many factors are unlikely to be equal. Variations in extrinsic mortality as well as in the pace of life--larger organisms are often near the slow end of the fast-slow life-history continuum--can make realized cancer incidences more equal across species than what would be observed in the absence of adaptive responses to cancer risk (alleviating the so-called Peto's paradox). We also discuss reasons why patterns across species can differ from within-species predictions. Even if natural selection diminishes cancer susceptibility differences between species, within-species differences can remain. In many sexually dimorphic cases, we predict males to be more cancer-prone than females, forming an understudied component of sexual conflict. PMID:26056356

  10. 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

  11. 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

  12. 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. PMID:23302296

  13. Life history of Manataria maculata (Lepidoptera: Satyrinae) from Costa Rica.

    PubMed

    Murillo, L Ricardo; Nishida, Kenji

    2003-06-01

    The life history and early stages of the satyrine butterfly Manataria maculata are described and illustrated from Costa Rica. Eggs are laid on Lasiacis sp. (Panicoideae), a new non-bamboo host plant for the genus Manataria. The larval stage varied from 23 to 28 days, and the pupal duration was approximately 12 days when reared on Bambusa vulgaris and Guadua angustifolia in captivity at 23-24 degrees C. PMID:15162739

  14. A New History of Animal Life on Earth

    NASA Astrophysics Data System (ADS)

    Ward, Peter

    2006-12-01

    The history of life since the advent of animals is one of rapid evolution by more complex animals and plants in response to changing environmental conditions. While the overall history of animals and plants from the Cambrian until the present has been well known for decades, it is in the history of the environmental changes that newer progress has been made. Understanding the changes in global temperature, oceanic chemistry, and atmospheric composition require more sophisticated analyses than simply charting the presence of absence of particular organisms as represented by their fossil record. In this talk I will concentrate on new environmental findings concerning the oceans and atmosphere over the last 500 million years that had only newly appreciated and major effects on not only the composition of flora and fauna, but on the very origination and extinction rates of these organisms. The role of oxygen and hydrogen sulfide in evolution and extinction are particularly interesting as lessons learned from their history on Earth have important Astrobiological implications for the frequency of advance life in the Universe.

  15. Brain ontogeny and life history in Pleistocene hominins.

    PubMed

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

    2015-03-01

    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

  16. 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. PMID:22707038

  17. 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. PMID:26926277

  18. 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. PMID:25807980

  19. 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

  20. Predation life history responses to increased temperature variability.

    PubMed

    Barbosa, Miguel; Pestana, Joao; Soares, Amadeu M V M

    2014-01-01

    The evolution of life history traits is regulated by energy expenditure, which is, in turn, governed by temperature. The forecasted increase in temperature variability is expected to impose greater stress to organisms, in turn influencing the balance of energy expenditure and consequently life history responses. Here we examine how increased temperature variability affects life history responses to predation. Individuals reared under constant temperatures responded to different levels of predation risk as appropriate: namely, by producing greater number of neonates of smaller sizes and reducing the time to first brood. In contrast, we detected no response to predation regime when temperature was more variable. In addition, population growth rate was slowest among individuals reared under variable temperatures. Increased temperature variability also affected the development of inducible defenses. The combined effects of failing to respond to predation risk, slower growth rate and the miss-match development of morphological defenses supports suggestions that increased variability in temperature poses a greater risk for species adaptation than that posed by a mean shift in temperature. PMID:25250677

  1. Predation Life History Responses to Increased Temperature Variability

    PubMed Central

    Barbosa, Miguel; Pestana, Joao; Soares, Amadeu M. V. M.

    2014-01-01

    The evolution of life history traits is regulated by energy expenditure, which is, in turn, governed by temperature. The forecasted increase in temperature variability is expected to impose greater stress to organisms, in turn influencing the balance of energy expenditure and consequently life history responses. Here we examine how increased temperature variability affects life history responses to predation. Individuals reared under constant temperatures responded to different levels of predation risk as appropriate: namely, by producing greater number of neonates of smaller sizes and reducing the time to first brood. In contrast, we detected no response to predation regime when temperature was more variable. In addition, population growth rate was slowest among individuals reared under variable temperatures. Increased temperature variability also affected the development of inducible defenses. The combined effects of failing to respond to predation risk, slower growth rate and the miss-match development of morphological defenses supports suggestions that increased variability in temperature poses a greater risk for species adaptation than that posed by a mean shift in temperature. PMID:25250677

  2. 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

  3. 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.

  4. 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.

  5. 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

  6. 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.

  7. End-of-life decisions in abusive head trauma.

    PubMed

    Ellingson, Clifford C; Livingston, Jared S; Fanaroff, Jonathan M

    2012-03-01

    Abusive head trauma is a significant and tragic cause of morbidity and mortality in infants and its victims often have a poor prognosis. With such high rates of morbidity and mortality, health care providers and parents are often faced with the decision to continue or discontinue life support for an affected child. Sadly, however, this decision becomes complicated when parents are accused of causing the victim-child's current state. In this situation, if life support is withdrawn, criminal charges for the accused may escalate from assault to murder. This escalation of legal charges creates a conflict of interest for accused parents. As a result, parents have a strong incentive to avoid murder charges by using their parental decision-making rights to keep the child alive, even when treatment is deemed futile or inhumane. In this article, we discuss the legal challenges health care providers may face when parents place their interest above their child's. We also propose solutions that give greater deference to the rights and interest of these critically ill children while still preserving protected parental rights. PMID:22311991

  8. Using decision analytic methods to assess the utility of family history tools.

    PubMed

    Tyagi, Anupam; Morris, Jill

    2003-02-01

    Family history may be a useful tool for identifying people at increased risk of disease and for developing targeted interventions for individuals at higher-than-average risk. This article addresses the issue of how to examine the utility of a family history tool for public health and preventive medicine. We propose the use of a decision analytic framework for the assessment of a family history tool and outline the major elements of a decision analytic approach, including analytic perspective, costs, outcome measurements, and data needed to assess the value of a family history tool. We describe the use of sensitivity analysis to address uncertainty in parameter values and imperfect information. To illustrate the use of decision analytic methods to assess the value of family history, we present an example analysis based on using family history of colorectal cancer to improve rates of colorectal cancer screening. PMID:12568827

  9. 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

  10. 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

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

    PubMed

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

    2012-02-01

    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

  12. 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…

  13. 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. PMID:22702169

  14. 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

  15. Ethical and practical principles underlying the end of life decisions.

    PubMed

    Sharma, B R

    2004-09-01

    "I will not relinquish old age, if it leaves my better part intact. But, if it begins to shake my mind, if it destroys its faculties one by one, if it leaves me not life but breath, I will depart from the putrid or tottering edifice. If I must suffer without hope or relief, I will depart, not through fear of the pain itself, but because it prevents all for which I would live." Seneca, the great Roman statesman of 1st century AD, spoke these words 2 millennia before the Netherlands became, on November 28, 2000, the first country in the world to legalize euthanasia. The decisions pertaining to end of life, whether legalized or otherwise, are practiced in many parts of the world but not reported on account of legal implications. Lack of awareness regarding the distinction between different procedures on account of legal status granted to them in some countries is the other area of concern. Debate among the medical practitioners, lawmakers, and the public taking into consideration the cultural, social, and religious ethos will lead to increased awareness, more safeguards, and improvement of medical decisions concerning the end of life. PMID:15322464

  16. Life and Death Decision Making, by Baruch A. Brody.

    PubMed

    Veatch, Robert M

    1989-04-01

    Veatch considers the pluralistic casuistry theory advocated by Baruch Brody in his 1988 book, Life and Death Decision Making, to be an important contribution to the secular medical ethics literature. The casuistic and pluralistic elements of Brody's new model are described as intriguing but controversial because Brody both excludes several ethical appeals (i.e., classical Hippocratic ethics, virtue theory) and/or limits other questionable appeals (i.e., consequences for families and others in society, the virtue of integrity) without accounting for these decisions. Veatch also questions Brody's use of intuitional judgment to determine what ought to be done after examination of various appeals and their significance because Brody's approach raises serious problems about how various appeals are counted. Veatch does affirm the rich assessment of medical ethical problems made possible by Brody's pluralistic approach but notes the difficulties it raises. PMID:11649246

  17. 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

  18. 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. PMID:26596528

  19. 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. PMID:23777235

  20. 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…

  1. Life history of lake herring in Lake Superior

    USGS Publications Warehouse

    Dryer, William R.; Beil, Joseph

    1964-01-01

    The average annual commercial catch of lake herring (Coregonus artedi) in U.S. waters of Lake Superior was nearly 12 million pounds in 1929-61. This production contributed 62.4 percent of the total U.S. take of lake herring for the Great Lakes. About 90 percent of the annual catch is taken from small-mesh gill nets during the November-December spawning season. The life-history studies were based on 12,187 fish collected in 1950-62; past growth was computed for 3,779 specimens collected from commercial landings at: Duluth, Minn.; Bayfield, Wis.; and Portage Entry and Marquette, Mich.

  2. 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

  3. 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

  4. A History of Black Achievement as Impacted by Federal Court Decisions in the Last Century

    ERIC Educational Resources Information Center

    Gooden, Mark A.

    2004-01-01

    The major decisions of pre-and post-Brown and the history of African American student achievement are discussed through an analysis of select federal court decisions. One can conclude that the struggle for equal educational opportunity for African Americans in the United States is vying for the attention of more conservative Federal Court judges.

  5. 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

  6. Life History Evolution and Genome Size in Subtribe Oncidiinae (Orchidaceae)

    PubMed Central

    CHASE, MARK W.; HANSON, LYNDA; ALBERT, VICTOR A.; WHITTEN, W. MARK; WILLIAMS, NORRIS H.

    2005-01-01

    • Background and Aims Within Oncidiinae, there are several groups of species that are effectively annuals, and we wished to see if these species had smaller genome sizes than average for the subtribe. • Methods Fifty-four genome size estimates (50 of which are new) for species in subtribe Oncidiinae (Orchidaceae) were examined for the first time in a phylogenetic context to evaluate hypotheses concerning genome sizes and life history traits. • Results and Conclusions Within the limits of still relatively sparse sampling, the species that are effectively annuals do appear to have smaller genome sizes than average. However, the genome sizes of their immediate sister group are also small, indicating that changes in genome size preceded the change in life history traits. Genome sizes and chromosome numbers also do not correlate; some slowly growing species have lower chromosome numbers but large genomes and vice versa. Based on a survey of the literature on orchids, it is also clear that epiphytic species have smaller genome sizes than do terrestrial species, which could be an effect of different water relations or the fact that most terrestrial orchids are geophytic or have distinct growth and dormancy phases. PMID:15596466

  7. Coevolutionary feedbacks between family interactions and life history.

    PubMed

    Stucki, Dimitri; Kölliker, Mathias

    2013-11-01

    Families with parental care show a parent-offspring conflict over the amount of parental investment. To date, the resolution of this conflict was modeled as being driven by either purely within-brood or between-brood competition. In reality the partitioning of parental resources within- versus between-broods is an evolving life history trait, which can be affected by parent-offspring interactions. This coevolutionary feedback between life history and family interactions may influence the evolutionary process and outcome of parent-offspring coadaptation. We used a genetic framework for a simulation model where we allowed parental parity to coevolve with traits that determine parental investment. The model included unlinked loci for clutch size, parental sensitivity, baseline provisioning, and offspring begging. The simulation showed that tight coadaptation of parent and offspring traits only occurred in iteroparous outcomes whereas semelparous outcomes were characterized by weak coadaptation. When genetic variation in clutch size was unrestricted in the ancestral population, semelparity and maximal begging with poor coadaptation evolved throughout. Conversely, when genetic variation was limited to iteroparous conditions, and/or when parental sensitivity was treated as an evolutionarily fixed sensory bias, coadapted outcomes were more likely. Our findings show the influence of a feedback between parity, coadaptation, and conflict on the evolution of parent-offspring interactions. PMID:24152003

  8. 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. PMID:25284486

  9. Life history strategy and young adult substance use.

    PubMed

    Richardson, George B; Chen, Ching-Chen; Dai, Chia-Liang; Swoboda, Christopher M

    2014-01-01

    This study tested whether life history strategy (LHS) and its intergenerational transmission could explain young adult use of common psychoactive substances. We tested a sequential structural equation model using data from the National Longitudinal Survey of Youth. During young adulthood, fast LHS explained 61% of the variance in overall liability for substance use. Faster parent LHS predicted poorer health and lesser alcohol use, greater neuroticism and cigarette smoking, but did not predict fast LHS or overall liability for substance use among young adults. Young adult neuroticism was independent of substance use controlling for fast LHS. The surprising finding of independence between parent and child LHS casts some uncertainty upon the identity of the parent and child LHS variables. Fast LHS may be the primary driver of young adult use of common psychoactive substances. However, it is possible that the young adult fast LHS variable is better defined as young adult mating competition. We discuss our findings in depth, chart out some intriguing new directions for life history research that may clarify the dimensionality of LHS and its mediation of the intergenerational transmission of substance use, and discuss implications for substance abuse prevention and treatment. PMID:25365695

  10. 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. PMID:23954434

  11. 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. PMID:21959168

  12. 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. PMID:24480323

  13. Effects of life history variation on size and growth in stream-dwelling Atlantic salmon

    USGS Publications Warehouse

    Letcher, B.H.; Gries, G.

    2003-01-01

    A large size variation amongst life histories for stream-dwelling Atlantic salmon Salmo salar was found and the relative effect of life histories on size varied over time. As early as December (age 0+ years), fish that later smolted at age 2+ years were significantly larger than fish that did not smolt at age 2+ years. In contrast, there were no mass differences at age 0+ years between fish that would mature or not at age 1+ years (October). The mass differences between smolts and non-smolts persisted until smolting, and differences between mature and immature fish first appeared in May (age 1+ years). Following September (age 1+ years), there was also a significant interaction between smolting and maturity. Previously mature and immature age 2+ year smolts were not significantly different in size, but immature age 2+ year non-smolts were much lighter than mature age 2+ year non-smolts. Based on mass differences, the apparent 'decision' to smolt occurred c. 5 months before (winter, age 0+ years) the decision to mature (late spring, age 1+ years). In addition to strong seasonal growth variation, sizes of freshwater Atlantic salmon were largely structured by the complex interaction between smolt-age and maturity. ?? 2003 The fisheries Society of the British Isles.

  14. 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. PMID:26874356

  15. 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. PMID:23926046

  16. 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

  17. 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.

  18. 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

  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. PMID:26378312

  20. 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

  1. 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.

  2. The life history of Acrochaete wittrockii (Ulvellaceae, Chlorophyta)

    NASA Astrophysics Data System (ADS)

    Kornmann, P.

    1993-06-01

    Acrochaete wittrockii (Wille) Nielsen is a heteromorphic diplohaplont. The haplophase consists of isomorphic, dioecious filamentous epiphytes on brown algae. Several generations follow each other by triflagellate zoospores from spring to early summer. By late summer and throughout autumn, quadriflagellate zoopores are produced by the epiphytic thalli; they give rise to male and female gametophytes of a globular, pseudoparenchymatic appearance in culture. The gametophytes produce anisogamic biflagellate gametes which, after gametic union, develop into diploid unicellular sporophytes. After 6 7 days, the sporophyte produces triflagellate zoospores, repeating the life history when germinating on brown algal hosts. Alternatively, triflagellate zoospores which settle on the bottom of petri dishes, develop into unicellular, autonomous sporangial plants. Their triflagellate spores repeat the epiphytic stage on brown algal hosts, or the sporangial plant cycle on non-living substrate, respectively.

  3. 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.

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

    PubMed

    Guo, Qinfeng

    2003-09-01

    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 terms 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 2 major issues that have been largely overlooked in current ecosystem management policies and conservation efforts: i) life history constraints; and ii) future global warming trends. It also addresses the importance of these 2 factors in balancing disturbance frequency and intensity for optimal biodiversity maintenance and ecosystem management. PMID:14627374

  5. 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%).

  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. PMID:27129737

  7. 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.

  8. Root traits explain different foraging strategies between resprouting life histories.

    PubMed

    Paula, Susana; Pausas, Juli G

    2011-02-01

    Drought and fire are prevalent disturbances in Mediterranean ecosystems. Plant species able to regrow after severe disturbances (i.e. resprouter life history) have higher allocation to roots and higher water potential during the dry season than coexisting non-resprouting species. However, seedlings of non-resprouters have a higher survival rate after summer drought. We predict that, to counteract their shallow-rooting systems and to maximize seedling survival, non-resprouters have root traits that confer higher efficiency in soil resource acquisition than resprouters. We tested this prediction in seedlings of less than 1.5 months old. We select 13 coexisting woody species (including both resprouters and non-resprouters), grew them in a common garden and measured the following root traits: length, surface, average diameter, root tissue density (RTD), specific root length (SRL), surface:volume ratio (SVR), specific tip density (STD), tip distribution in depth, internal links ratio (ILR), and degree of branching. These root traits were compared between the two resprouting life histories using both standard cross-species and phylogenetic-informed analysis. Non-resprouters showed higher SRL and longer, thinner and more branched laterals, especially in the upper soil layers. The external links (i.e. the most absorptive root region) were also more abundant, longer, thinner and with higher SVR for non-resprouters. The results were supported by the phylogenetic-informed analysis for the root traits most strongly related to soil resource acquisition (SRL, SVR and branching pattern). The seedling root structure of non-resprouters species allows them to more efficiently explore the upper soil layer, whereas seedling roots of resprouters will permit both carbon storage and deep soil penetration. PMID:20960009

  9. Childbearing history, later-life health, and mortality in Germany.

    PubMed

    Hank, Karsten

    2010-11-01

    Using data from the German Socio-Economic Panel, we investigated the role of childbearing history in later-life health and mortality, paying particular attention to possible differences by sex and region. Higher parity is associated with better self-rated health in West German mothers and fathers aged 50+, but its relationship with East German women's physical health and survival is negative. Early motherhood is paralleled by poorer physical health in West Germany, whereas late motherhood is associated with lower psychological well-being in Eastern Germany. Moreover, among West German women, having had a non-marital first birth is weakly correlated with poorer physical health. Our findings support the notion of biosocial pathways playing an important role in shaping the fertility-health nexus. Specifically, the West German 'male-breadwinner' model of specialization appears to have buffered the stresses associated with childrearing, whereas fertility off the 'normative' life-course track appears to have had adverse effects on women's health in West Germany. PMID:20845224

  10. Learning about Self-Advocacy from Life History: A Case Study from the United States

    ERIC Educational Resources Information Center

    Traustadottir, Rannveig

    2006-01-01

    Many people with learning difficulties want to tell the stories of their life and have done so in collaboration with academic researchers. Life histories of people with learning difficulties are a good way to learn about self-advocacy. Life histories can tell us about how self-advocacy began and the support people need to be self-advocates. Tom…

  11. 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. PMID:26655355

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

    PubMed

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

    2014-11-01

    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. PMID:25051533

  13. 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.

  14. 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. PMID:26791094

  15. 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

  16. 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

  17. 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…

  18. 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)

  19. 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. PMID:18337281

  20. Sexual selection constrained by life history in a butterfly.

    PubMed Central

    Kemp, Darrell J

    2002-01-01

    Trait evolution via sexual selection has traditionally been viewed as isolated from life-history constraints. Recent theoretical treatments, however, predict that costly sexually selected characters should be mediated by the same allocational trade-offs that apply to more conventional aspects of reproductive investment. Participation in risky competitive behaviours, for example male-male combat, should therefore increase as the opportunity for future reproduction declines. However, the demonstration of such trade-offs has proven to be elusive due to concomitant age-based variation in the physical determinants of fighting 'ability'. Here, I exploit the unique nature of a butterfly contest system to provide compelling evidence for lifetime partitioning of risky and aggressive sexually selected behaviours. I show that male Hypolimnas bolina become more willing to persist in contests over mating territories, and more generally accepting of injury risks, as they age. Contest persistence in this species is not mediated simply by physical condition, and I experimentally isolate the effect of ageing per se from resource ownership and previous contest experience. These results demonstrate how sexually selected behaviours can be ultimately mediated by a shifting trade-off between contemporary reproductive effort and future opportunities. PMID:12079656

  1. 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.

  2. 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.

  3. 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…

  4. 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…

  5. 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. PMID:23388862

  6. Size-dependent mortality induces life-history changes mediated through population dynamical feedbacks.

    PubMed

    van Kooten, Tobias; Persson, Lennart; de Roos, André M

    2007-08-01

    The majority of taxa grow significantly during life history, which often leads to individuals of the same species having different ecological roles, depending on their size or life stage. One aspect of life history that changes during ontogeny is mortality. When individual growth and development are resource dependent, changes in mortality can affect the outcome of size-dependent intraspecific resource competition, in turn affecting both life history and population dynamics. We study the outcome of varying size-dependent mortality on two life-history types, one that feeds on the same resource throughout life history and another that can alternatively cannibalize smaller conspecifics. Compensatory responses in the life history dampen the effect of certain types of size-dependent mortality, while other types of mortality lead to dramatic changes in life history and population dynamics, including population (de-)stabilization, and the growth of cannibalistic giants. These responses differ strongly among the two life-history types. Our analysis provides a mechanistic understanding of the population-level effects that come about through the interaction between individual growth and size-dependent mortality, mediated by resource dependence in individual vital rates. PMID:17874376

  7. 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

  8. Nutrition, hormones and life history in burying beetles.

    PubMed

    Trumbo, Stephen T; Robinson, Gene E

    2004-05-01

    Nutrition, hormones and the allocation of physiological resources are intricately related. To investigate these inter-relationships in female burying beetles (Nicrophorus spp.), we examined the effect of diet quality on juvenile hormone (JH) levels and reproduction, and the effect of JH supplementation on reproduction and resistance to starvation. Nicrophorus orbicollis adult females fed a less preferred mealworm larvae diet gained less body mass, had smaller ovaries and had lower titers of JH in their hemolymph than females fed a preferred blowfly diet. When presented a carcass for breeding, females on a less preferred diet oviposited 33% fewer eggs, and eggs were of 18% less mass. Females on the less preferred diet also took longer to begin oviposition as indicated indirectly by the time when their eggs hatched. To investigate the effects of JH, independent of nutrition, JH was topically applied to single and paired females of Nicrophorus tomentosus. When presented a carcass, JH-treated paired females oviposited more eggs (28%-year 1, 44%-year 2) than control females, and also showed a trend toward faster oviposition. JH supplementation had a greater effect on single females. JH treatment increased the proportion of single females attempting reproduction (at least one viable larva), increased the number of eggs (69%-year 1, 123%-year 2), and increased the proportion of females ovipositing early. In separate experiments, treatment with JH or a JH analog negatively affected resistance to starvation in three species. Treatment with JH reduced starvation survival by 10.3% days in N. tomentosus females. Treatment with the JH analog methoprene reduced starvation survival 17.8% in N. orbicollis females and by 18% in Ptomascopus morio females. These results suggest that JH has positive and negative effects on different components of life history. PMID:15121451

  9. 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. PMID:26989019

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

    USGS Publications Warehouse

    Eberhardt, L.L.; O'Shea, Thomas J.

    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

  11. 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

  12. 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

  13. 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).…

  14. 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…

  15. Life history theory and breast cancer risk: methodological and theoretical challenges

    PubMed Central

    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. PMID:26874356

  16. Host Responses in Life-History Traits and Tolerance to Virus Infection in Arabidopsis thaliana

    PubMed Central

    Pagán, Israel; Alonso-Blanco, Carlos; García-Arenal, Fernando

    2008-01-01

    Knowing how hosts respond to parasite infection is paramount in understanding the effects of parasites on host populations and hence host–parasite co-evolution. Modification of life-history traits in response to parasitism has received less attention than other defence strategies. Life-history theory predicts that parasitised hosts will increase reproductive effort and accelerate reproduction. However, empirical analyses of these predictions are few and mostly limited to animal-parasite systems. We have analysed life-history trait responses in 18 accessions of Arabidopsis thaliana infected at two different developmental stages with three strains of Cucumber mosaic virus (CMV). Accessions were divided into two groups according to allometric relationships; these groups differed also in their tolerance to CMV infection. Life-history trait modification upon virus infection depended on the host genotype and the stage at infection. While all accessions delayed flowering, only the more tolerant allometric group modified resource allocation to increase the production of reproductive structures and progeny, and reduced the length of reproductive period. Our results are in agreement with modifications of life-history traits reported for parasitised animals and with predictions from life-history theory. Thus, we provide empirical support for the general validity of theoretical predictions. In addition, this experimental approach allowed us to quantitatively estimate the genetic determinism of life-history trait plasticity and to evaluate the role of life-history trait modification in defence against parasites, two largely unexplored issues. PMID:18704166

  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. 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.

  19. 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…

  20. Life History and Collective Memory as Methodological Strategies: Studying Teacher Professionalism

    ERIC Educational Resources Information Center

    Goodson, Ivor; Choi, Pik Lin

    2008-01-01

    The life history method, which achieved a prominent position in the Chicago tradition of sociological research in the early 1920s, has been widely adopted for educational inquiries since the 1980s. The power of the life history method in illuminating subjective teacher experiences in social historical contexts has made it "probably the only…

  1. Understanding a Pakistani Science Teacher's Practice through a Life History Study

    ERIC Educational Resources Information Center

    Halai, Nelofer

    2011-01-01

    The purpose of the single case life history study was to understand a female science teacher's conceptions of the nature of science as explicit in her practice. While this paper highlights these understandings, an additional purpose is to give a detailed account of the process of creating a life history account through more than 13 in-depth…

  2. 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…

  3. 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. PMID:25534504

  4. 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. PMID:24852016

  5. 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

  6. 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. PMID:25478151

  7. 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

  8. 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…

  9. 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

  10. 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. PMID:20549112

  11. The Family Life Course and Health: Partnership, Fertility Histories, and Later-Life Physical Health Trajectories in Australia.

    PubMed

    O'Flaherty, Martin; Baxter, Janeen; Haynes, Michele; Turrell, Gavin

    2016-06-01

    Life course perspectives suggest that later-life health reflects long-term social patterns over an individual's life: in particular, the occurrence and timing of key roles and transitions. Such social patterns have been demonstrated empirically for multiple aspects of fertility and partnership histories, including timing of births and marriage, parity, and the presence and timing of a marital disruption. Most previous studies have, however, addressed particular aspects of fertility or partnership histories singly. We build on this research by examining how a holistic classification of family life course trajectories from ages 18 to 50, incorporating both fertility and partnership histories, is linked to later-life physical health for a sample of Australian residents. Our results indicate that long-term family life course trajectories are strongly linked to later-life health for men but only minimally for women. For men, family trajectories characterized by early family formation, no family formation, an early marital disruption, or high fertility are associated with poorer physical health. Among women, only those who experienced both a disrupted marital history and a high level of fertility were found to be in poorer health. PMID:27189018

  12. 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.

  13. Late-Life and Life History Predictors of Older Adults of High-Risk Alcohol Consumption and Drinking Problems

    PubMed Central

    Moos, Rudolf H.; Schutte, Kathleen K.; Brennan, Penny L.; Moos, Bernice S.

    2009-01-01

    Aims This prospective, longitudinal study focused on late-life and life history predictors of high-risk alcohol consumption and drinking problems during a 20-year interval as adults matured from age 55–65 to age 75–85. Design, Setting, Participants A sample of older community residents (N=719) who had consumed alcohol in the past year or shortly before was surveyed at baseline and 10 years and 20 years later. Measurements At each contact point, participants completed an inventory that assessed their alcohol consumption, drinking problems, and personal and life context factors. Participants also provided information about their life history of drinking and help-seeking. Results Older adults who, at baseline, had more friends who approved of drinking, relied on substances for tension reduction, and had more financial resources were more likely to engage in high-risk alcohol consumption and to incur drinking problems at 10-year and 20-year follow-ups. With respect to life history factors, drinking problems by age 50 were associated with a higher likelihood of late-life high-risk alcohol consumption and drinking problems; having tried to cut down on drinking and participation in Alcoholics Anonymous were associated with a lower likelihood of high-risk consumption and problems. Conclusion Specific late-life and life history factors can identify older adults likely to engage in excessive alcohol consumption 10 and 20 years later. Targeted screening that considers current alcohol consumption and life context, and history of drinking problems and help-seeking, could help identify older adults at higher risk for excessive or problematic drinking. PMID:19969428

  14. 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. PMID:26808102

  15. Inbreeding depression accumulation across life-history stages of the endangered Takahe.

    PubMed

    Grueber, Catherine E; Laws, Rebecca J; Nakagawa, Shinichi; Jamieson, Ian G

    2010-12-01

    Studies evaluating the impact of inbreeding depression on population viability of threatened species tend to focus on the effects of inbreeding at a single life-history stage (e.g., juvenile survival). We examined the effects of inbreeding across the full life-history continuum, from survival up to adulthood, to subsequent reproductive success, and to the recruitment of second-generation offspring, in wild Takahe ( Porphyrio hochstetteri ) by analyzing pedigree and fitness data collected over 21 breeding seasons. Although the effect size of inbreeding at individual life-history stages was small, inbreeding depression accumulated across multiple life-history stages and ultimately reduced long-term fitness (i.e., successful recruitment of second-generation offspring). The estimated total lethal equivalents (2B) summed across all life-history stages were substantial (16.05, 95% CI 0.08-90.8) and equivalent to an 88% reduction in recruitment of second-generation offspring for closely related pairs (e.g., sib-sib pairings) relative to unrelated pairs (according to the pedigree). A history of small population size in the Takahe could have contributed to partial purging of the genetic load and the low level of inbreeding depression detected at each single life-history stage. Nevertheless, our results indicate that such "purged" populations can still exhibit substantial inbreeding depression, especially when small but negative fitness effects accumulate across the species' life history. Because inbreeding depression can ultimately affect population viability of small, isolated populations, our results illustrate the importance of measuring the effects of inbreeding across the full life-history continuum. PMID:20586788

  16. 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. PMID:24308926

  17. Empowering family members in end-of-life care decision making in the intensive care unit.

    PubMed

    Browning, Annette M

    2009-01-01

    Critical care nurses are often faced with working with families during the end-of-life care of a loved one. Often there is indecisiveness in family members of critically ill patients when faced with making these difficult decisions. The purpose of this manuscript is to describe origins of indecisiveness in family members of critically ill patients who are faced with end-of-life care decisions. Strategies to empower family members during this crucial time are also discussed. PMID:19104247

  18. 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…

  19. The complexity of life and death decisions in mitosis

    PubMed Central

    Diaz-Martinez, Laura A; Yu, Hongtao

    2015-01-01

    The anticancer drug taxol stabilizes microtubules and activates the spindle checkpoint, causing prolonged mitotic arrest in cancer cells. Our recent work suggests that the cellular decision to live or die following mitotic arrest is a complex process involving crosstalk between competing apoptotic and adaptation pathways. PMID:27308420

  20. The evolution of predictive adaptive responses in human life history

    PubMed Central

    Nettle, Daniel; Frankenhuis, Willem E.; Rickard, Ian J.

    2013-01-01

    Many studies in humans have shown that adverse experience in early life is associated with accelerated reproductive timing, and there is comparative evidence for similar effects in other animals. There are two different classes of adaptive explanation for associations between early-life adversity and accelerated reproduction, both based on the idea of predictive adaptive responses (PARs). According to external PAR hypotheses, early-life adversity provides a ‘weather forecast’ of the environmental conditions into which the individual will mature, and it is adaptive for the individual to develop an appropriate phenotype for this anticipated environment. In internal PAR hypotheses, early-life adversity has a lasting negative impact on the individual's somatic state, such that her health is likely to fail more rapidly as she gets older, and there is an advantage to adjusting her reproductive schedule accordingly. We use a model of fluctuating environments to derive evolveability conditions for acceleration of reproductive timing in response to early-life adversity in a long-lived organism. For acceleration to evolve via the external PAR process, early-life cues must have a high degree of validity and the level of annual autocorrelation in the individual's environment must be almost perfect. For acceleration to evolve via the internal PAR process requires that early-life experience must determine a significant fraction of the variance in survival prospects in adulthood. The two processes are not mutually exclusive, and mechanisms for calibrating reproductive timing on the basis of early experience could evolve through a combination of the predictive value of early-life adversity for the later environment and its negative impact on somatic state. PMID:23843395

  1. Understanding Health Care Decisions (at the End of Life)

    MedlinePlus

    ... do? America is a rich melting pot of religions, races, and cultures. Ingrained in each tradition are ... end of life. You might say: In my religion, we … (then describe your religious traditions regarding death). ...

  2. Video May Aid End-of-Life Decision-Making

    MedlinePlus

    ... These options included: life-prolonging care such as CPR, having a tube inserted into their windpipe and ... such as intravenous therapy and hospitalization, but no CPR or breathing machine; and comfort care. Comfort care, ...

  3. Curriculum as natural history: A life-history case study of an alternative science learning program

    NASA Astrophysics Data System (ADS)

    Windward, Rolfe

    The aim of this study is to further our understanding of the nexus between individual development and conceptions of science curriculum with particular emphasis upon root metaphors. The initial conceptual springboard is based upon the rather consistent conflation of selectionist (Darwinian) and developmental cosmologies in most scientific thinking about complex systems. A partial goal of this study then being the development of a visual metaphor that offers a more coherent heuristic of what it means to be a knowing individual within a changing ecosocial reality. This is a paradigmatic examination and it is conjectured that the root assumptions underlying the bulk of curriculum theory are unrealistic, that the appearance of stability in curriculum and practice is largely a byproduct of misclassification or even category error, and that reconceptualizing curriculum as a description of an adaptive system rather than a system-by-design will assist in unpacking a number of problems including the so-called theory-practice gap. The basic procedure is a life-history case study of seven participants--three female high school students, three male high school students, and their teacher--tracked between three learning contexts: the classroom, an extracurricular science "institute," and a virtual astronomy class. The biography of the researcher is incorporated both as a matter of methodology and as a matter of interventionist stance. It is concluded that the 'science institute' embodied a number of innovative features, including more equality among all participants, that also allowed masking-off of countervailing forces perceived as antithetical to its own development. Its organization was not stable but constituted a strongly expansive instrument in the individuation of all participants, allowing the students to more clearly visualize the multiple natures of science and themselves as individuals and scientists. It also allowed the teacher involved to leverage change in his

  4. 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.

  5. 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. PMID:24622241

  6. 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

  7. 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

  8. Does life history predict risk-taking behavior of wintering dabbling ducks?

    USGS Publications Warehouse

    Ackerman, J.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.

  9. 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. PMID:24184868

  10. 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

  11. 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

  12. 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.

  13. 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

  14. 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…

  15. 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

  16. 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

  17. 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.

  18. 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, and Kurt…

  19. 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…

  20. [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. PMID:21368542

  1. A Life History of the Squash Vine Borer, Melittia Cucurbitae (Harris) (Lepidoptera: Sesiidae) in South Carolina

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The life history of the squash vine borer (Lepidoptera: Sesiidae) was investigated in South Carolina. Duration of life stages, numbers of progeny, and mortality rates for SVB were determined in cages held at 25 plus minus 2C, 65-70% humidity and a photoperiod of 16:8 (L:D) h in a rearing room, and ...

  2. Effect of Temperature on the life history of the mealybug, Paracoccus marginatus (Hemiptera: Pseudococcidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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,...

  3. 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.…

  4. 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 ...

  5. The influence of mortality and socioeconomic status on risk and delayed rewards: a life history theory approach.

    PubMed

    Griskevicius, Vladas; Tybur, Joshua M; Delton, Andrew W; Robertson, Theresa E

    2011-06-01

    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

  6. 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. PMID:26887788

  7. 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

  8. 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.

  9. 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. PMID:20021762

  10. 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. PMID:24957971

  11. 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.

  12. Seasonal time constraints reduce genetic variation in life-history traits along a latitudinal gradient.

    PubMed

    Sniegula, Szymon; Golab, Maria J; Drobniak, Szymon M; Johansson, Frank

    2016-01-01

    Time constraints cause strong selection on life-history traits, because populations need to complete their life cycles within a shorter time. We therefore expect lower genetic variation in these traits in high- than in low-latitude populations, since the former are more time-constrained. The aim was to estimate life-history traits and their genetic variation in an obligately univoltine damselfly along a latitudinal gradient of 2730 km. Populations were grown in the laboratory at temperatures and photoperiods simulating those at their place of origin. In a complementary experiment, individuals from the same families were grown in constant temperature and photoperiod that mimicked average conditions across the latitude. Development time and size was faster and smaller, respectively, and growth rate was higher at northern latitudes. Additive genetic variance was very low for life-history traits, and estimates for egg development time and larval growth rate showed significant decreases towards northern latitudes. The expression of genetic effects in life-history traits differed considerably when individuals were grown in constant rather than simulated and naturally variable conditions. Our results support strong selection by time constraints. They also highlight the importance of growing organisms in their native environment for correct estimates of genetic variance at their place of origin. Our results also suggest that the evolutionary potential of life-history traits is very low at northern compared to southern latitudes, but that changes in climate could alter this pattern. PMID:26333659

  13. 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

  14. 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. PMID:26538016

  15. 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

  16. The effects of asymmetric competition on the life history of Trinidadian guppies.

    PubMed

    Bassar, Ronald D; Childs, Dylan Z; Rees, Mark; Tuljapurkar, Shripad; Reznick, David N; Coulson, Tim

    2016-03-01

    The effects of asymmetric interactions on population dynamics has been widely investigated, but there has been little work aimed at understanding how life history parameters like generation time, life expectancy and the variance in lifetime reproductive success are impacted by different types of competition. We develop a new framework for incorporating trait-mediated density-dependence into size-structured models and use Trinidadian guppies to show how different types of competitive interactions impact life history parameters. Our results show the degree of symmetry in competitive interactions can have dramatic effects on the speed of the life history. For some vital rates, shifting the competitive superiority from small to large individuals resulted in a doubling of the generation time. Such large influences of competitive symmetry on the timescale of demographic processes, and hence evolution, highlights the interwoven nature of ecological and evolutionary processes and the importance of density-dependence in understanding eco-evolutionary dynamics. PMID:26843397

  17. 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. PMID:26249034

  18. 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.

  19. 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

  20. 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. PMID:26393343

  1. 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.

  2. 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. PMID:23356321

  3. 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

  4. 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.

  5. 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.

  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. 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.

  8. Retrospective study of doctors' "end of life decisions" in caring for mentally handicapped people in institutions in The Netherlands.

    PubMed Central

    van Thiel, G. J.; van Delden, J. J.; de Haan, K.; Huibers, A. K.

    1997-01-01

    OBJECTIVES: To gain insight into the reasons behind and the prevalence of doctors' decisions at the end of life that might hasten a patient's death ("end of life decisions") in institutions caring for mentally handicapped people in the Netherlands, and to describe important aspects of the decisions making process. DESIGN: Survey of random sample of doctors caring for mentally handicapped people by means of self completed questionnaires and structured interviews. SUBJECTS: 89 of the 101 selected doctors completed the questionnaire. 67 doctors had taken an end of life decision and were interviewed about their most recent case. MAIN OUTCOME MEASURES: Prevalence of end of life decisions; types of decisions; characteristics of patients; reasons why the decision was taken; and the decision making process. RESULTS: The 89 doctors reported 222 deaths for 1995. An end of life decision was taken in 97 cases (44%); in 75 the decision was to withdraw or withhold treatment, and in 22 it was to relieve pain or symptoms with opiates in dosages that may have shortened life. In the 67 most recent cases with an end of life decision the patients were mostly incompetent (63) and under 65 years old (51). Only two patients explicitly asked to die, but in 23 cases there had been some communication with the patient. In 60 cases the doctors discussed the decision with nursing staff and in 46 with a colleague. CONCLUSIONS: End of life decisions are an important aspect of the institutionalised care of mentally handicapped people. The proportion of such decisions in the total number of deaths is similar to that in other specialties. However, the discussion of such decisions is less open in the care of mental handicap than in other specialties. Because of distinctive features of care in this specialty an open debate about end of life decisions should not be postponed. PMID:9240047

  9. Remarkable life history polymorphism may be evolving under divergent selection in the silverleaf sunflower.

    PubMed

    Moyers, Brook T; Rieseberg, Loren H

    2016-08-01

    Substantial intraspecific variation in life history is rare and potentially a signal of incipient ecological speciation, if variation is driven by geographically heterogenous natural selection. We present the first report of extensive life history polymorphism in Helianthus argophyllus, the silverleaf sunflower, and examine evidence for its evolution by divergent selection. In 18 populations sampled from across the species range and grown in a common garden, most quantitative traits covaried such that individuals could be assigned to two distinct life history syndromes: tall and late flowering with small initial flowerheads, or short and early flowering with larger initial flowerheads. Helianthus argophyllus exhibits regional genetic structure, but this population structure does not closely correspond with patterns of phenotypic variation. The early-flowering syndrome is primarily observed in populations from coastal barrier islands, while populations from the nearby mainland coast, although geographically and genetically close, are primarily late flowering. Additionally, several traits are more differentiated among regions than expected based on neutral genetic divergence (QST  > FST ), including the first principal component score corresponding with life history syndrome. This discordance between patterns of phenotypic and genetic variation suggests that divergent selection is driving genetic differences in life history across the species range. If so, the silverleaf sunflower may be in early stages of ecological speciation. PMID:27288664

  10. The Importance of Population Growth and Regulation in Human Life History Evolution

    PubMed Central

    Baldini, Ryan

    2015-01-01

    Explaining the evolution of human life history traits remains an important challenge for evolutionary anthropologists. Progress is hindered by a poor appreciation of how demographic factors affect the action of natural selection. I review life history theory showing that the quantity maximized by selection depends on whether and how population growth is regulated. I show that the common use of R, a strategy’s expected lifetime number of offspring, as a fitness maximand is only appropriate under a strict set of conditions, which are apparently unappreciated by anthropologists. To concretely show how demography-free life history theory can lead to errors, I reanalyze an influential model of human life history evolution, which investigated the coevolution of a long lifespan and late age of maturity. I show that the model’s conclusions do not hold under simple changes to the implicitly assumed mechanism of density dependence, even when stated assumptions remain unchanged. This analysis suggests that progress in human life history theory requires better understanding of the demography of our ancestors. PMID:25830310