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

Onset and establishment of diazotrophs and other bacterial associates in the early life history stages of the coral Acropora millepora.

PubMed

Lema, Kimberley A; Bourne, David G; Willis, Bette L

2014-10-01

Early establishment of coral-microbial symbioses is fundamental to the fitness of corals, but comparatively little is known about the onset and succession of bacterial communities in their early life history stages. In this study, bacterial associates of the coral Acropora millepora were characterized throughout the first year of life, from larvae and 1-week-old juveniles reared in laboratory conditions in the absence of the dinoflagellate endosymbiont Symbiodinium to field-outplanted juveniles with established Symbiodinium symbioses, and sampled at 2 weeks and at 3, 6 and 12 months. Using an amplicon pyrosequencing approach, the diversity of both nitrogen-fixing bacteria and of bacterial communities overall was assessed through analysis of nifH and 16S rRNA genes, respectively. The consistent presence of sequences affiliated with diazotrophs of the order Rhizobiales (23-58% of retrieved nifH sequences; 2-12% of 16S rRNA sequences), across all samples from larvae to 12-month-old coral juveniles, highlights the likely functional importance of this nitrogen-fixing order to the coral holobiont. Dominance of Roseobacter-affiliated sequences (>55% of retrieved 16S rRNA sequences) in larvae and 1-week-old juveniles, and the consistent presence of sequences related to Oceanospirillales and Altermonadales throughout all early life history stages, signifies their potential importance as coral associates. Increased diversity of bacterial communities once juveniles were transferred to the field, particularly of Cyanobacteria and Deltaproteobacteria, demonstrates horizontal (environmental) uptake of coral-associated bacterial communities. Although overall bacterial communities were dynamic, bacteria with likely important functional roles remain stable throughout early life stages of Acropora millepora. © 2014 John Wiley & Sons Ltd.

Conditions on Early Mars Might Have Fostered Rapid and Early Development of Life

NASA Technical Reports Server (NTRS)

Gibson, Everett K.; McKay, David S.; Thomas-Keprta, Kathie L.; Clemett, Simon J.; Wentworth, Susan J.

2007-01-01

The exploration of Mars during the past decades has begun to unveil the history of the planet. The combinations of remote sensing, in situ geochemical compositional measurements and photographic observations from both above and on the surface have shown Mars to have a dynamic and active geologic evolution. Mars geologic evolution clearly had conditions that were suitable for supporting life. For a planet to be able to be habitable, it must have water, carbon sources, energy sources and a dynamic geologic past. Mars meets all of these requirements. The first 600 My of Martian history were ripe for life to develop because of the abundance of (i) Water-carved canyons and oceans or lakes with the early presence of near surface water shown by precipitated carbonates in ALH84001 well-dated at approx.3.9 Gy., (ii) Energy from the original accretional processes, a molten core which generated a strong magnetic field leaving a permanent record in the early crust, early active volcanism continuing throughout Martian history, and, and continuing impact processes, (iii) Carbon and water from possibly extensive volcanic outgassing (i.e. H2O, CO2, CH4, CO, O2, N2, H2S, SO2, etc.) and (iv) some crustal tectonics as revealed by faulting and possible plate movement reflected by the magnetic pattern in the crust. The question arises: "Why would life not evolve from these favorable conditions on early Mars in its first 600 My?" During this period, it seems likely that environmental near-surface conditions on Mars were more favorable to life than at any later time. Standing bodies of water, precipitation and flowing surface water, and possibly abundant hydrothermal energy would all favor the formation of early life. Even if life developed elsewhere (on Earth, Venus, or on other solar systems) and was transported to Mars, the surface conditions were likely very hospitable for that introduced life to multiply and evolve.

Early life history and survival of natural subyearling fall chinook salmon in the Snake and Clearwater rivers in 1995

USGS Publications Warehouse

Connor, William P.; Bjornn, Theodore C.; Burge, Howard L.; Garcia, Aaron P.; Rondorf, Dennis W.

1997-01-01

The objectives of this segment of our study were to (1) describe the early life history characteristics of naturally produced subyearling fall chinook salmon in the Snake and Clearwater rivers, and (2) estimate survival for juvenile fall chinook salmon emigrating from the Snake and Clearwater rivers to the tail race of Lower Granite Dam.

Life history strategy of the honey bee, Apis mellifera.

PubMed

Seeley, Thomas D

1978-01-01

The feral honey bee queens (colonies) of central New York State (USA) show a K-type life history strategy. Their demographic characteristics include low early life mortality, low reproductive rate, long lifespan, high population stability and repeated reproductions. Identifying the life history strategy of these bees reveals the general pattern of selection for competitive ability, rather than productivity, which has shaped their societies. Selection for competitive power explains the adaptiveness (compared with alternatives found in many other insect societies) of the large perennial colonies, infrequent but expensive offspring, and efficient foraging which characterize the social organization of these bees.

Influences of spawning timing, water temperature, and climatic warming on early life history phenology in western Alaska sockeye salmon

USGS Publications Warehouse

Sparks, Morgan M.; Falke, Jeffrey A.; Quinn, Thomas P.; Adkison, Milo D.; Schindler, Daniel E.; Bartz, Krista K.; Young, Daniel B.; Westley, Peter A. H.

2018-01-01

We applied an empirical model to predict hatching and emergence timing for 25 western Alaska sockeye salmon (Oncorhynchus nerka) populations in four lake-nursery systems to explore current patterns and potential responses of early life history phenology to warming water temperatures. Given experienced temperature regimes during development, we predicted hatching to occur in as few as 58 d to as many as 260 d depending on spawning timing and temperature. For a focal lake spawning population, our climate-lake temperature model predicted a water temperature increase of 0.7 to 1.4 °C from 2015 to 2099 during the incubation period, which translated to a 16 d to 30 d earlier hatching timing. The most extreme scenarios of warming advanced development by approximately a week earlier than historical minima and thus climatic warming may lead to only modest shifts in phenology during the early life history stage of this population. The marked variation in the predicted timing of hatching and emergence among populations in close proximity on the landscape may serve to buffer this metapopulation from climate change.

Barium distributions in teeth reveal early life dietary transitions in primates

PubMed Central

Austin, Christine; Smith, Tanya M.; Bradman, Asa; Hinde, Katie; Joannes-Boyau, Renaud; Bishop, David; Hare, Dominic J.; Doble, Philip; Eskenazi, Brenda; Arora, Manish

2013-01-01

Early life dietary transitions reflect fundamental aspects of primate evolution and are important determinants of health in contemporary human populations1,2. Weaning is critical to developmental and reproductive rates; early weaning can have detrimental health effects but enables shorter inter-birth intervals, which influences population growth3. Uncovering early life dietary history in fossils is hampered by the absence of prospectively-validated biomarkers that are not modified during fossilisation4. Here we show that major dietary shifts in early life manifest as compositional variations in dental tissues. Teeth from human children and captive macaques, with prospectively-recorded diet histories, demonstrate that barium (Ba) distributions accurately reflect dietary transitions from the introduction of mother’s milk and through the weaning process. We also document transitions in a Middle Palaeolithic juvenile Neanderthal, which shows a pattern of exclusive breastfeeding for seven months, followed by seven months of supplementation. After this point, Ba levels in enamel returned to baseline prenatal levels, suggesting an abrupt cessation of breastfeeding at 1.2 years of age. Integration of Ba spatial distributions and histological mapping of tooth formation enables novel studies of the evolution of human life history, dietary ontogeny in wild primates, and human health investigations through accurate reconstructions of breastfeeding history. PMID:23698370

Barium distributions in teeth reveal early-life dietary transitions in primates.

PubMed

Austin, Christine; Smith, Tanya M; Bradman, Asa; Hinde, Katie; Joannes-Boyau, Renaud; Bishop, David; Hare, Dominic J; Doble, Philip; Eskenazi, Brenda; Arora, Manish

2013-06-13

Early-life dietary transitions reflect fundamental aspects of primate evolution and are important determinants of health in contemporary human populations. Weaning is critical to developmental and reproductive rates; early weaning can have detrimental health effects but enables shorter inter-birth intervals, which influences population growth. Uncovering early-life dietary history in fossils is hampered by the absence of prospectively validated biomarkers that are not modified during fossilization. Here we show that large dietary shifts in early life manifest as compositional variations in dental tissues. Teeth from human children and captive macaques, with prospectively recorded diet histories, demonstrate that barium (Ba) distributions accurately reflect dietary transitions from the introduction of mother's milk through the weaning process. We also document dietary transitions in a Middle Palaeolithic juvenile Neanderthal, which shows a pattern of exclusive breastfeeding for seven months, followed by seven months of supplementation. After this point, Ba levels in enamel returned to baseline prenatal levels, indicating an abrupt cessation of breastfeeding at 1.2 years of age. Integration of Ba spatial distributions and histological mapping of tooth formation enables novel studies of the evolution of human life history, dietary ontogeny in wild primates, and human health investigations through accurate reconstructions of breastfeeding history.

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.

Mammalian brain development and our grandmothering life history.

PubMed

Hawkes, Kristen; Finlay, Barbara L

2018-05-02

Among mammals, including humans, adult brain size and the relative size of brain components depend precisely on the duration of a highly regular process of neural development. Much wider variation is seen in rates of body growth and the state of neural maturation at life history events like birth and weaning. Large brains result from slow maturation, which in humans is accompanied by weaning early with respect to both neural maturation and longevity. The grandmother hypothesis proposes this distinctive combination of life history features evolved as ancestral populations began to depend on foods that just weaned juveniles couldn't handle. Here we trace possible reciprocal connections between brain development and life history, highlighting the resulting extended neural plasticity in a wider cognitive ecology of allomaternal care that distinguishes human ontogeny with consequences for other peculiarities of our lineage. Copyright © 2018 Elsevier Inc. All rights reserved.

Development of Life on Early Mars

NASA Technical Reports Server (NTRS)

Gibson, Everett K.; McKay, David S.; Thomas-Keprta, Kathie L.; Clemett, Simon J.; Wentworth, Susan J.

2009-01-01

Exploration of Mars has begun to unveil the history of the planet. Combinations of remote sensing, in situ compositional measurements and photographic observations have shown Mars had a dynamic and active geologic evolution. Mars geologic evolution encompassed conditions that were suitable for supporting life. A habitable planet must have water, carbon and energy sources along with a dynamic geologic past. Mars meets all of these requirements. The first 600 My of Martian history were ripe for life to develop because of the abundance of (i) Water- as shown by carved canyons and oceans or lakes with the early presence of near surface water shown by precipitated carbonates in ALH84001, well-dated at 3.9 Gy, (ii) Energy from the original accretional processes, a molten core which generated a strong magnetic field leaving a permanent record in the early crust, active volcanism continuing throughout Martian history, and continuing impact processes, (iii) Carbon, water and a likely thicker atmosphere from extensive volcanic outgassing (i.e. H20, CO2, CH4, CO, O2, N2, H2S, SO2, etc.) and (iv) crustal tectonics as revealed by faulting and possible plate movement reflected by the magnetic pattern in the crust [1]. The question arises: "Why would life not develop from these favorable conditions on Mars in its first 600 My?" During this period, environmental near-surface conditions on Mars were more favorable to life than at any later time. Standing bodies of water, precipitation and flowing surface water, and possibly abundant hydrothermal energy would favor the formation of early life. (Even if life developed elsewhere on Earth, Venus, or on other bodies-it was transported to Mars where surface conditions were suitable for life to evolve). The commonly stated requirement that life would need hundreds of millions of year to get started is only an assumption; we know of no evidence that requires such a long interval for the development of life, if the proper habitable

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

Implications of life-history strategies for obesity

PubMed Central

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

2017-01-01

The association between low socioeconomic status (SES) and obesity is well documented. In the current research, a life history theory (LHT) framework provided an explanation for this association. Derived from evolutionary behavioral science, LHT emphasizes how variability in exposure to unpredictability during childhood gives rise to individual differences in a range of social psychological processes across the life course. Consistent with previous LHT research, the current findings suggest that exposure to unpredictability during childhood (a characteristic common to low SES environments) is associated with the adoption of a fast life-history strategy, one marked by impulsivity and a focus on short-term goals. We demonstrate that a fast life-history strategy, in turn, was associated with dysregulated weight-management behaviors (i.e., eating even in the absence of hunger), which were predictive of having a high body mass index (BMI) and being obese. In both studies, findings held while controlling for participants’ current socioeconomic status, suggesting that obesity is rooted in childhood experiences. A serial mediation model in study 2 confirmed that effects of childhood SES on adult BMI and obesity can be explained in part by exposure to unpredictability, the adoption of a fast life-history strategy, and dysregulated-eating behaviors. These findings suggest that weight problems in adulthood may be rooted partially in early childhood exposure to unpredictable events and environments. LHT provides a valuable explanatory framework for understanding the root causes of obesity. PMID:28739939

Assessment of visual perception in adolescents with a history of central coordination disorder in early life – 15-year follow-up study

PubMed Central

Kowalski, Ireneusz M.; Domagalska, Małgorzata; Szopa, Andrzej; Dwornik, Michał; Kujawa, Jolanta; Stępień, Agnieszka; Śliwiński, Zbigniew

2012-01-01

Introduction Central nervous system damage in early life results in both quantitative and qualitative abnormalities of psychomotor development. Late sequelae of these disturbances may include visual perception disorders which not only affect the ability to read and write but also generally influence the child's intellectual development. This study sought to determine whether a central coordination disorder (CCD) in early life treated according to Vojta's method with elements of the sensory integration (S-I) and neuro-developmental treatment (NDT)/Bobath approaches affects development of visual perception later in life. Material and methods The study involved 44 participants aged 15-16 years, including 19 diagnosed with moderate or severe CCD in the neonatal period, i.e. during the first 2-3 months of life, with diagnosed mild degree neonatal encephalopathy due to perinatal anoxia, and 25 healthy people without a history of developmental psychomotor disturbances in the neonatal period. The study tool was a visual perception IQ test comprising 96 graphic tasks. Results The study revealed equal proportions of participants (p < 0.05) defined as very skilled (94-96), skilled (91-94), aerage (71-91), poor (67-71), and very poor (0-67) in both groups. These results mean that adolescents with a history of CCD in the neonatal period did not differ with regard to the level of visual perception from their peers who had not demonstrated psychomotor development disorders in the neonatal period. Conclusions Early treatment of children with CCD affords a possibility of normalising their psychomotor development early enough to prevent consequences in the form of cognitive impairments in later life. PMID:23185199

An experimental manipulation of life-history trajectories and resistance to oxidative stress.

PubMed

Alonso-Alvarez, Carlos; Bertrand, Sophie; Devevey, Godefroy; Prost, Josiane; Faivre, Bruno; Chastel, Olivier; Sorci, Gabriele

2006-09-01

Optimal investment into life-history traits depends on the environmental conditions that organisms are likely to experience during their life. Evolutionary theory tells us that optimal investment in reproduction versus maintenance is likely to shape the pattern of age-associated decline in performance, also known as aging. The currency that is traded against different vital functions is, however, still debated. Here, we took advantage of a phenotypic manipulation of individual quality in early life to explore (1) long-term consequences on life-history trajectories, and (2) the possible physiological mechanism underlying the life-history adjustments. We manipulated phenotypic quality of a cohort of captive zebra finches (Taeniopygia guttata) by assigning breeding pairs to either an enlarged or a reduced brood. Nestlings raised in enlarged broods were in poorer condition than nestlings raised in reduced broods. Interestingly, the effect of environmental conditions experienced during early life extended to the age at first reproduction. Birds from enlarged broods delayed reproduction. Birds that delayed reproduction produced less offspring but lived longer, although neither fecundity nor longevity were directly affected by the experimental brood size. Using the framework of the life-table response experiment modeling, we also explored the effect of early environmental condition on population growth rate and aging. Birds raised in reduced broods tended to have a higher population growth rate, and a steeper decrease of reproductive value with age than birds reared in enlarged broods. Metabolic resources necessary to fight off the damaging effect of reactive oxygen species (ROS) could be the mechanism underlying the observed results, as (1) birds that engaged in a higher number of breeding events had a weaker red blood cell resistance to oxidative stress, (2) red blood cell resistance to oxidative stress predicted short-term mortality (but not longevity), and (3) was

Social anxiety and negative early life events in university students.

PubMed

Binelli, Cynthia; Ortiz, Ana; Muñiz, Armando; Gelabert, Estel; Ferraz, Liliana; S Filho, Alaor; Crippa, José Alexandre S; Nardi, Antonio E; Subirà, Susana; Martín-Santos, Rocío

2012-06-01

There is substantial evidence regarding the impact of negative life events during childhood on the aetiology of psychiatric disorders. We examined the association between negative early life events and social anxiety in a sample of 571 Spanish University students. In a cross-sectional survey conducted in 2007, we collected data through a semistructured questionnaire of sociodemographic variables, personal and family psychiatric history, and substance abuse. We assessed the five early negative life events: (i) the loss of someone close, (ii) emotional abuse, (iii) physical abuse, (iv) family violence, and (v) sexual abuse. All participants completed the Liebowitz Social Anxiety Scale. Mean (SD) age was 21 (4.5), 75% female, LSAS score was 40 (DP = 22), 14.2% had a psychiatric family history and 50.6% had negative life events during childhood. Linear regression analyses, after controlling for age, gender, and family psychiatric history, showed a positive association between family violence and social score (p = 0.03). None of the remaining stressors produced a significant increase in LSAS score (p > 0.05). University students with high levels of social anxiety presented higher prevalence of negative early life events. Thus, childhood family violence could be a risk factor for social anxiety in such a population.

Early Mars: A Warm Wet Niche for Life

NASA Technical Reports Server (NTRS)

Gibson, Everett K.; McKay, David S.; Thomas-Keprta, Kathie L.; Clemett, Simon J.

2010-01-01

Exploration of Mars has begun to unveil the history of the planet. Combinations of remote sensing, in situ compositional measurements and photographic observations have shown Mars had a dynamic and active geologic evolution. Mars geologic evolution had conditions that were suitable for supporting life. A habitable planet must have water, carbon and energy sources along with a dynamic geologic past. Mars meets all of these requirements. The first 600 Ma of Martian history were ripe for life to develop because of the abundance of: (i) Water-as shown by carved canyons and oceans or lakes with the early presence of near surface water shown by precipitated carbonates in ALH84001, well-dated at approx.3.9 Ga, (ii) Energy from the original accretional processes, a molten core which generated a strong magnetic field leaving a permanent record in the early crust, active volcanism continuing throughout Martian history, and continuing impact processes, (iii) Carbon, water and a likely thicker atmosphere from extensive volcanic outgassing (i.e. H2O, CO2, CH4, CO, O2, N2, H2S, SO2, etc.) and (iv) crustal tectonics as revealed by faulting and possible plate movement reflected by the magnetic patterns in the crust [1]. The question arises: "Why would life not develop from these favorable conditions on Mars in its first 600 Ma?" During this period, environmental near-surface conditions on Mars were more favorable to life than at any later time. Standing bodies of water, precipitation and flowing surface water, and possibly abundant hydrothermal energy would favor the formation of early life. (Even if life developed elsewhere on Earth, Venus, or on other bodies-it was transported to Mars where surface conditions were suitable for life to evolve)

An Ecological Analysis of the Effects of Deviant Peer Clustering on Sexual Promiscuity, Problem Behavior, and Childbearing from Early Adolescence to Adulthood: An Enhancement of the Life History Framework

PubMed Central

Dishion, Thomas J.; Ha, Thao; Véronneau, Marie-Hélène

2012-01-01

This study proposes the inclusion of peer relationships in a life history perspective on adolescent problem behavior. Longitudinal analyses were used to examine deviant peer clustering as the mediating link between attenuated family ties, peer marginalization, and social disadvantage in early adolescence and sexual promiscuity in middle adolescence and childbearing by early adulthood. Specifically, 998 youth and their families were assessed at age 11 years and periodically through age 24 years. Structural equation modeling revealed that the peer-enhanced life history model provided a good fit to the longitudinal data, with deviant peer clustering strongly predicting adolescent sexual promiscuity and other correlated problem behaviors. Sexual promiscuity, as expected, also strongly predicted the number of children by age 22–24 years. Consistent with a life history perspective, family social disadvantage directly predicted deviant peer clustering and number of children in early adulthood, controlling for all other variables in the model. These data suggest that deviant peer clustering is a core dimension of a fast life history strategy, with strong links to sexual activity and childbearing. The implications of these findings are discussed with respect to the need to integrate an evolutionary-based model of self-organized peer groups in developmental and intervention science. PMID:22409765

An ecological analysis of the effects of deviant peer clustering on sexual promiscuity, problem behavior, and childbearing from early adolescence to adulthood: an enhancement of the life history framework.

PubMed

Dishion, Thomas J; Ha, Thao; Véronneau, Marie-Hélène

2012-05-01

The authors propose that peer relationships should be included in a life history perspective on adolescent problem behavior. Longitudinal analyses were used to examine deviant peer clustering as the mediating link between attenuated family ties, peer marginalization, and social disadvantage in early adolescence and sexual promiscuity in middle adolescence and childbearing by early adulthood. Specifically, 998 youths, along with their families, were assessed at age 11 years and periodically through age 24 years. Structural equation modeling revealed that the peer-enhanced life history model provided a good fit to the longitudinal data, with deviant peer clustering strongly predicting adolescent sexual promiscuity and other correlated problem behaviors. Sexual promiscuity, as expected, also strongly predicted the number of children by ages 22-24 years. Consistent with a life history perspective, family social disadvantage directly predicted deviant peer clustering and number of children in early adulthood, controlling for all other variables in the model. These data suggest that deviant peer clustering is a core dimension of a fast life history strategy, with strong links to sexual activity and childbearing. The implications of these findings are discussed with respect to the need to integrate an evolutionary-based model of self-organized peer groups in developmental and intervention science.

Life history tradeoffs in cancer evolution

PubMed Central

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

2014-01-01

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

Reproductive ecology and early life history traits of the brooding coral, Porites astreoides, from shallow to mesophotic zones

NASA Astrophysics Data System (ADS)

Goodbody-Gringley, Gretchen; Wong, Kevin H.; Becker, Danielle M.; Glennon, Keegan; de Putron, Samantha J.

2018-06-01

Early life history traits of brooding corals are often affected by the environmental conditions experienced by parental colonies. Such parental effects can impact offspring survival, which influences the overall success of a population as well as resilience to environmental challenges. This study examines the reproductive ecology and early life history traits of the brooding coral Porites astreoides across a depth gradient in Bermuda. Fecundity, larval size, larval Symbiodinium density, and settlement success, as well as post-metamorphic juvenile survival, growth, and Symbiodinium density were compared across three reef sites representing an inshore patch reef (2-5 m), an offshore rim reef (8-10 m), and an upper-mesophotic reef (30-33 m). Although fecundity did not differ across sites, larvae produced by colonies on the patch reef site were smaller, had lower Symbiodinium densities, and had lower rates of settlement and juvenile survival compared to larvae from colonies on the rim and upper-mesophotic reef sites. Larvae produced by colonies from the rim and upper-mesophotic sites did not differ in size or Symbiodinium densities; however, rates of settlement, growth, and survival were higher for larvae from the upper-mesophotic site compared to those from the rim reef site. These results indicate that offspring quality and success vary among sites with differing environmental conditions and may imply higher recruitment potential and resilience for upper-mesophotic corals.

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.

Tough Adults, Frail Babies: An Analysis of Stress Sensitivity across Early Life-History Stages of Widely Introduced Marine Invertebrates

PubMed Central

Pineda, M. Carmen; McQuaid, Christopher D.; Turon, Xavier; López-Legentil, Susanna; Ordóñez, Víctor; Rius, Marc

2012-01-01

All ontogenetic stages of a life cycle are exposed to environmental conditions so that population persistence depends on the performance of both adults and offspring. Most studies analysing the influence of abiotic conditions on species performance have focussed on adults, while studies covering early life-history stages remain rare. We investigated the responses of early stages of two widely introduced ascidians, Styela plicata and Microcosmus squamiger, to different abiotic conditions. Stressors mimicked conditions in the habitats where both species can be found in their distributional ranges and responses were related to the selection potential of their populations by analysing their genetic diversity. Four developmental stages (egg fertilisation, larval development, settlement, metamorphosis) were studied after exposure to high temperature (30°C), low salinities (26 and 22‰) and high copper concentrations (25, 50 and 100 µg/L). Although most stressors effectively led to failure of complete development (fertilisation through metamorphosis), fertilisation and larval development were the most sensitive stages. All the studied stressors affected the development of both species, though responses differed with stage and stressor. S. plicata was overall more resistant to copper, and some stages of M. squamiger to low salinities. No relationship was found between parental genetic composition and responses to stressors. We conclude that successful development can be prevented at several life-history stages, and therefore, it is essential to consider multiple stages when assessing species' abilities to tolerate stress. Moreover, we found that early development of these species cannot be completed under conditions prevailing where adults live. These populations must therefore recruit from elsewhere or reproduce during temporal windows of more benign conditions. Alternatively, novel strategies or behaviours that increase overall reproductive success might be

Earliest evidence of modern human life history in North African early Homo sapiens.

PubMed

Smith, Tanya M; Tafforeau, Paul; Reid, Donald J; Grün, Rainer; Eggins, Stephen; Boutakiout, Mohamed; Hublin, Jean-Jacques

2007-04-10

Recent developmental studies demonstrate that early fossil hominins possessed shorter growth periods than living humans, implying disparate life histories. Analyses of incremental features in teeth provide an accurate means of assessing the age at death of developing dentitions, facilitating direct comparisons with fossil and modern humans. It is currently unknown when and where the prolonged modern human developmental condition originated. Here, an application of x-ray synchrotron microtomography reveals that an early Homo sapiens juvenile from Morocco dated at 160,000 years before present displays an equivalent degree of tooth development to modern European children at the same age. Crown formation times in the juvenile's macrodont dentition are higher than modern human mean values, whereas root development is accelerated relative to modern humans but is less than living apes and some fossil hominins. The juvenile from Jebel Irhoud is currently the oldest-known member of Homo with a developmental pattern (degree of eruption, developmental stage, and crown formation time) that is more similar to modern H. sapiens than to earlier members of Homo. This study also underscores the continuing importance of North Africa for understanding the origins of human anatomical and behavioral modernity. Corresponding biological and cultural changes may have appeared relatively late in the course of human evolution.

Early-Life Stressors, Personality Development, and Fast Life Strategies: An Evolutionary Perspective on Malevolent Personality Features.

PubMed

Csathó, Árpád; Birkás, Béla

2018-01-01

Life history theory posits that behavioral adaptation to various environmental (ecological and/or social) conditions encountered during childhood is regulated by a wide variety of different traits resulting in various behavioral strategies. Unpredictable and harsh conditions tend to produce fast life history strategies, characterized by early maturation, a higher number of sexual partners to whom one is less attached, and less parenting of offspring. Unpredictability and harshness not only affects dispositional social and emotional functioning, but may also promote the development of personality traits linked to higher rates of instability in social relationships or more self-interested behavior. Similarly, detrimental childhood experiences, such as poor parental care or high parent-child conflict, affect personality development and may create a more distrustful, malicious interpersonal style. The aim of this brief review is to survey and summarize findings on the impact of negative early-life experiences on the development of personality and fast life history strategies. By demonstrating that there are parallels in adaptations to adversity in these two domains, we hope to lend weight to current and future attempts to provide a comprehensive insight of personality traits and functions at the ultimate and proximate levels.

Life-history strategies of ungulates

USGS Publications Warehouse

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

1999-01-01

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

Early life history of the yellow perch, Perca flavescens (Mitchill), in the Red Lakes, Minnesota

USGS Publications Warehouse

Pycha, Richard L.; Smith, Lloyd L.

1955-01-01

The early life history of the yellow perch, an important commercial species in the Red Lakes, Minnesota, has been studied with special reference to length at scale formation, growth rate during first season of life, and food habits as they relate to growth and survival. Scales are fully imbricated in the area of 12th to 14th lateral line scales at 24 millimeters total length. There is a wide annual varition in first season's growth which is not correlated with growth in older fish. Body-scale relationship is rectilinear from 24 to 280 millimeters. Length-weight relationship during the first year is expressed by the equation W = 0.6198 × 10−5 L3.1251 which is very similar to that describing the relationship in later years. Stomach analysis indicates food is primarily plankton but in some seasons fish may be strongly dependent on bottom forms. Variations in food availability appear to be associated with changes in growth and may have a major influence on survival.

Life Detection on the Early Earth

NASA Technical Reports Server (NTRS)

Runnegar, B.

2004-01-01

Finding evidence for first the existence, and then the nature of life on the early Earth or early Mars requires both the recognition of subtle biosignatures and the elimination of false positives. The history of the search for fossils in increasingly older Precambrian strata illustrates these difficulties very clearly, and new observational and theoretical approaches are both needed and being developed. At the microscopic level of investigation, three-dimensional morphological characterization coupled with in situ chemical (isotopic, elemental, structural) analysis is the desirable first step. Geological context is paramount, as has been demonstrated by the controversies over AH84001, the Greenland graphites, and the Apex chert microfossils . At larger scales, the nature of sedimentary bedforms and the structures they display becomes crucial, and here the methods of condensed matter physics prove most useful in discriminating between biological and non-biological constructions. Ultimately, a combination of geochemical, morphological, and contextural evidence may be required for certain life detection on the early Earth or elsewhere.

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

PubMed

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

2010-07-01

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

Local Adaptation at the Transcriptome Level in Brown Trout: Evidence from Early Life History Temperature Genomic Reaction Norms

PubMed Central

Meier, Kristian; Hansen, Michael Møller; Normandeau, Eric; Mensberg, Karen-Lise D.; Frydenberg, Jane; Larsen, Peter Foged; Bekkevold, Dorte; Bernatchez, Louis

2014-01-01

Local adaptation and its underlying molecular basis has long been a key focus in evolutionary biology. There has recently been increased interest in the evolutionary role of plasticity and the molecular mechanisms underlying local adaptation. Using transcriptome analysis, we assessed differences in gene expression profiles for three brown trout (Salmo trutta) populations, one resident and two anadromous, experiencing different temperature regimes in the wild. The study was based on an F2 generation raised in a common garden setting. A previous study of the F1 generation revealed different reaction norms and significantly higher QST than FST among populations for two early life-history traits. In the present study we investigated if genomic reaction norm patterns were also present at the transcriptome level. Eggs from the three populations were incubated at two temperatures (5 and 8 degrees C) representing conditions encountered in the local environments. Global gene expression for fry at the stage of first feeding was analysed using a 32k cDNA microarray. The results revealed differences in gene expression between populations and temperatures and population × temperature interactions, the latter indicating locally adapted reaction norms. Moreover, the reaction norms paralleled those observed previously at early life-history traits. We identified 90 cDNA clones among the genes with an interaction effect that were differently expressed between the ecologically divergent populations. These included genes involved in immune- and stress response. We observed less plasticity in the resident as compared to the anadromous populations, possibly reflecting that the degree of environmental heterogeneity encountered by individuals throughout their life cycle will select for variable level of phenotypic plasticity at the transcriptome level. Our study demonstrates the usefulness of transcriptome approaches to identify genes with different temperature reaction norms. The

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

USGS Publications Warehouse

Meador, Michael R.; Brown, Larry M.

2015-01-01

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

The positive and negative consequences of stressors during early life.

PubMed

Monaghan, Pat; Haussmann, Mark F

2015-11-01

We discuss the long-term effects of stress exposure in pre- and early postnal life. We present an evolutionary framework within which such effects can be viewed, and describe how the outcomes might vary with species life histories. We focus on stressors that induce increases in glucocorticoid hormones and discuss the advantages of an experimental approach. We describe a number of studies demonstrating how exposure to these hormones in early life can influence stress responsiveness and have substantial long-term, negative consequences for adult longevity. We also describe how early life exposure to mild levels of stressors can have beneficial effects on resilience to stress in later life, and discuss how the balance of costs and benefits is likely dependent on the nature of the adult environment. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Osteoporosis in survivors of early life starvation.

PubMed

Weisz, George M; Albury, William R

2013-01-01

The objective of this study was to provide evidence for the association of early life nutritional deprivation and adult osteoporosis, in order to suggest that a history of such deprivation may be an indicator of increased risk of osteoporosis in later life. The 'fetal programming' of a range of metabolic and cardiovascular disorders in adults was first proposed in the 1990s and more recently extended to disorders of bone metabolism. Localised famines during World War II left populations in whom the long-term effects of maternal, fetal and infantile nutritional deprivation were studied. These studies supported the original concept of 'fetal programming' but did not consider bone metabolism. The present paper offers clinical data from another cohort of World War II famine survivors - those from the Holocaust. The data presented here, specifically addressing the issue of osteoporosis, report on 11 Holocaust survivors in Australia (five females, six males) who were exposed to starvation in early life. The cases show, in addition to other metabolic disorders associated with early life starvation, various levels of osteoporosis, often with premature onset. The cohort studied is too small to support firm conclusions, but the evidence suggests that the risk of adult osteoporosis in both males and females is increased by severe starvation early in life - not just in the period from gestation to infancy but also in childhood and young adulthood. It is recommended that epidemiological research on this issue be undertaken, to assist planning for the future health needs of immigrants to Australia coming from famine affected backgrounds. Pending such research, it would be prudent for primary care health workers to be alert to the prima facie association between early life starvation and adult osteoporosis, and to take this factor into account along with other indicators when assessing a patient's risk of osteoporosis in later life.

Fermilab History and Archives Project | Golden Books - The Early History of

Science.gov Websites

Fermilab History and Archives Project Home About the Archives History and Archives Online Request Contact ; - The Early History of URA and Fermilab Fermilab Golden Book Collection main page Click on Image for Larger View The Early History of URA and Fermilab Viewpoint of a URA President (1966-1981) Norman F

Contributions of dynamic environmental signals during life-cycle transitions to early life-history traits in lodgepole pine (Pinus contorta Dougl.)

NASA Astrophysics Data System (ADS)

Liu, Y.; Wang, T.; El-Kassaby, Y. A.

2015-08-01

Environmental signals are important triggers in the life-cycle transitions and play a crucial role in the life-history evolution. Yet, very little is known about the leading ecological factors contributing to the variations of life-history traits in perennial plants. This paper explores both the causes and consequences for the evolution of life-history traits (i.e., seed dormancy and size) in lodgepole pine (Pinus contorta Dougl.) across British Columbia (B.C.), Canada. We selected 83 logepole pine populations covering 22 ecosystem zones of B.C. and through their geographic coordinate, 197 climatic variables were generated accordingly for the reference (1961-1990) and future (2041-2070) periods. We found that dynamic climatic variables rather than constant geographic variables are the true environmental driving forces in seed dormancy and size variations and thus provide reliable predictors in response to global climate change. Evapotranspiration and precipitation in the plant-to-seed chronology are the most critical climate variables for seed dormancy and size variations, respectively. Hence, we predicted that levels of seed dormancy in lodgepole pine would increase across large tracts of B.C. in 2050s. Winter-chilling is able to increase the magnitude of life-history plasticity and lower the bet-hedge strategy in the seed-to-plant transition; however, winter-chilling is likely to be insufficient in the north of 49° N in 2050s, which may delay germination while unfavourable conditions during dry summers may result in adverse consequences in the survival of seedlings owing to extended germination span.

Early Life Conditions, Adverse Life Events, and Chewing Ability at Middle and Later Adulthood

PubMed Central

Watt, Richard G.; Tsakos, Georgios

2014-01-01

Objectives. We sought to determine the extent to which early life conditions and adverse life events impact chewing ability in middle and later adulthood. Methods. Secondary analyses were conducted based on data from waves 2 and 3 of the Survey of Health, Ageing, and Retirement in Europe (SHARE), collected in the years 2006 to 2009 and encompassing information on current chewing ability and the life history of persons aged 50 years or older from 13 European countries. Logistic regression models were estimated with sequential inclusion of explanatory variables representing living conditions in childhood and adverse life events. Results. After controlling for current determinants of chewing ability at age 50 years or older, certain childhood and later life course socioeconomic, behavioral, and cognitive factors became evident as correlates of chewing ability at age 50 years or older. Specifically, childhood financial hardship was identified as an early life predictor of chewing ability at age 50 years or older (odds ratio = 1.58; 95% confidence interval = 1.22, 2.06). Conclusions. Findings suggest a potential enduring impact of early life conditions and adverse life events on oral health in middle and later adulthood and are relevant for public health decision-makers who design strategies for optimal oral health. PMID:24625140

Variations in early life history traits of Japanese anchovy Engraulis japonicus in the Yangtze River Estuary.

PubMed

Liu, Chunlong; Xian, Weiwei; Liu, Shude; Chen, Yifeng

2018-01-01

Resources of Japanese anchovy ( Engraulis japonicus Temminck & Schlegel, 1846) are undergoing dramatic recessions in China as the consequence of intensifying anthropogenic activities. Elucidating the influences of local-scale environmental factors on early life history traits is of great importance to design strategies conserving and restoring the declining anchovy resources. In this research, we studied hatching date and early growth of anchovy in the Yangtze River Estuary (YRE) using information obtained from otolith microstructure. Onset of hatching season and growth rates of anchovy was compared to populations in Japan and Taiwan. In YRE, the hatching date of anchovy ranged from February 26th to April 6th and mean growth rate ranged from 0.27 to 0.77 mm/d. Anchovies hatching later had higher growth rates than individuals hatching earlier before the 25th day. Among populations, hatching onsets of anchovy from the higher latitude were later than populations in the lower latitude, and growth rates of anchovy in YRE were much lower than populations in Japan and Taiwan. Variations in hatching onsets and early growth patterns of anchovy thus provide important knowledge on understanding the adaptation of anchovy in YRE and designing management strategies on conserving China's anchovy resources.

Contributions of dynamic environmental signals during life-cycle transitions to early life-history traits in lodgepole pine (Pinus contorta Dougl.)

NASA Astrophysics Data System (ADS)

Liu, Yang; Wang, Tongli; El-Kassaby, Yousry A.

2016-05-01

Environmental signals are important triggers in the life-cycle transitions and play a crucial role in the life-history evolution. Yet very little is known about the leading ecological factors contributing to the variations of life-history traits in perennial plants. This paper explores both the causes and consequences for the evolution of life-history traits (i.e., seed dormancy and size) in lodgepole pine (Pinus contorta Dougl.) across British Columbia (B.C.), Canada. We selected 83 logepole pine populations covering 22 ecosystem zones of B.C. and through their geographic coordinate, 197 climatic variables were generated accordingly for the reference (1961-1990) and future (2041-2070) periods. We found that dynamic climatic variables rather than constant geographic variables are the true environmental driving forces in seed dormancy and size variations and thus provide reliable predictors in response to global climate change. Evapotranspiration and precipitation in the plant-to-seed chronology are the most critical climate variables for seed dormancy and size variations, respectively. Hence, we predicted that levels of seed dormancy in lodgepole pine would increase across large tracts of B.C. in 2050s. Winter-chilling is able to increase the magnitude of life-history plasticity and lower the bet-hedge strategy in the seed-to-plant transition; however, winter-chilling is likely to be insufficient in the north of 49° N in 2050s, which may delay germination while unfavorable conditions during dry summers may result in adverse consequences in the survival of seedlings owing to extended germination span. These findings provide useful information to studies related to assessments of seed transfer and tree adaptation.

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. © 2016 Society for Conservation Biology.

The association between parental life history and offspring phenotype in Atlantic salmon.

PubMed

Van Leeuwen, Travis E; McLennan, Darryl; McKelvey, Simon; Stewart, David C; Adams, Colin E; Metcalfe, Neil B

2016-02-01

In many taxa there is considerable intraspecific variation in life history strategies from within a single population, reflecting alternative routes through which organisms can achieve successful reproduction. Atlantic salmon Salmo salar (Linnaeus) show some of the greatest within-population variability in life history strategies amongst vertebrates, with multiple discrete male and female life histories co-existing and interbreeding on many spawning grounds, although the effect of the various combinations of life histories on offspring traits remains unknown. Using crosses of wild fish we show here that the life history strategy of both parents was significantly associated with a range of offspring traits. Mothers that had spent longer at sea (2 versus 1 year) produced offspring that were heavier, longer and in better condition at the time of first feeding. However, these relationships disappeared shortly after fry had begun feeding exogenously. At this stage, the juvenile rearing environment (i.e. time spent in fresh water as juveniles) of the mother was a better predictor of offspring traits, with mothers that were faster to develop in fresh water (migrating to sea after two rather than three years of age) producing offspring that had higher maximal metabolic rates, aerobic scopes, and that grew faster. Faster developing fathers (1 year old sneaker males) tended to produce offspring that had higher maximal metabolic rates, were in better body condition and grew faster. The results suggest that both genetic effects and those related to parental early and late life history contribute to offspring traits. © 2016. Published by The Company of Biologists Ltd.

Early Childhood Education Teachers: Life History, Life Course, and the Problem of Family-Work Balance

ERIC Educational Resources Information Center

Bullough, Robert V., Jr.

2016-01-01

In contrast to the wider education literature, rather little is known about the lives of early childhood education (ECE) teachers and the impact of those lives on their practice. Drawing on surveys completed by Head Start assistant and lead teachers, teacher lifelines, and interviews, and through the lens of life-course theory, the author portrays…

Intersections of life histories and science identities: the stories of three preservice elementary teachers

NASA Astrophysics Data System (ADS)

Avraamidou, Lucy

2016-03-01

Grounded within Connelly and Clandinin's conceptualization of teachers' professional identity in terms of 'stories to live by' and through a life-history lens, this multiple case study aimed to respond to the following questions: (a) How do three preservice elementary teachers view themselves as future science teachers? (b) How have the participants' life histories shaped their science identity trajectories? In order to characterize the participants' formation of science identities over time, various data regarding their life histories in relation to science were collected: science biographies, self-portraits, interviews, reflective journals, lesson plans, and classroom observations. The analysis of the data illustrated how the three participants' identities have been in formation from the early years of their lives and how various events, experiences, and interactions had shaped their identities through time and across contexts. These findings are discussed alongside implications for theory, specifically, identity and life-history intersections, for teacher preparation, and for research related to explorations of beginning elementary teachers' identity trajectories.

Early reproductive maturity among Pumé foragers: Implications of a pooled energy model to fast life histories.

PubMed

Kramer, Karen L; Greaves, Russell D; Ellison, Peter T

2009-01-01

Life history theory places central importance on relationships between ontogeny, reproduction, and mortality. Fast human life histories have been theoretically and empirically associated with high mortality regimes. This relationship, however, poses an unanswered question about energy allocation. In epidemiologically stressful environments, a greater proportion of energy is allocated to immune function. If growth and maintenance are competing energetic expenditures, less energy should be available for growth, and the mechanism to sustain rapid maturation remains unclear. The human pattern of extended juvenile provisioning and resource sharing may provide an important source of variation in energy availability not predicted by tradeoff models that assume independence at weaning. We consider a group of South American foragers to evaluate the effects that pooled energy budgets may have on early reproduction. Despite growing up in an environment with distinct seasonal under-nutrition, harsh epidemiological conditions, and no health care, Pumé girls mature quickly and initiate childbearing in their midteens. Pooled energy budgets compensate for the low productivity of girls not only through direct food transfers but importantly by reducing energy they would otherwise expend in foraging activities to meet metabolic requirements. We suggest that pooled energy budgets affect energy availability at both extrinsic and intrinsic levels. Because energy budgets are pooled, Pumé girls and young women are buffered from environmental downturns and can maximize energy allocated to growth completion and initiate reproduction earlier than a traditional bound-energy model would predict. 2009 Wiley-Liss, Inc.

The Juvenile Transition: A Developmental Switch Point in Human Life History

ERIC Educational Resources Information Center

Del Giudice, Marco; Angeleri, Romina; Manera, Valeria

2009-01-01

This paper presents a new perspective on the transition from early to middle childhood (i.e., human juvenility), investigated in an integrative evolutionary framework. Juvenility is a crucial life history stage, when social learning and interaction with peers become central developmental functions; here it is argued that the "juvenile transition"…

Examination of associations between early life victimisation and alcohol's harm from others.

PubMed

Kaplan, Lauren M; Greenfield, Thomas K; Karriker-Jaffe, Katherine J

2018-03-01

Study aims were to examine: (i) how physical and sexual victimisation in early life are associated with alcohol's harm from others; and (ii) whether respondents' current drinking is a mediator of the association between early life victimisation and alcohol's harm from others among men and women. Data were from national computer-assisted telephone interviews, using the landline sample (3335 men and 3520 women ages ≥18) from the 2010 US National Alcohol Survey. Harms from someone else's drinking included family/marital problems, financial troubles, assault and vandalism in the past 12 months. Victimisation was measured with severe physical abuse or sexual assault before age 18. Severe physical or sexual victimisation before age 18 was reported by 3.4% of men and 8.1% of women. Significantly more men (5.2%) than women (2.4%) reported assault by other drinkers, and significantly more women reported family/marital (5.3%) and financial problems (2.8%) than did men (2.6 and 1% respectively). Severe early life victimisation was robustly associated with a greater likelihood of experiencing past-year harms from other drinkers for both men and women. Men's drinking partially mediated associations between early life victimisation and recent assaults and vandalism by other drinkers. Early life victimisation may increase risk of harms from someone else's drinking. Health services and interventions that screen for histories of victimisation may help decrease risk of later harms from others' drinking. Reductions in drinking among men with histories of victimisation also could help reduce their exposure to such harms. [Kaplan LM, Greenfield TK, Karriker-Jaffe KJ. Examination of associations between early life victimisation and alcohol's harm from others. © 2017 Australasian Professional Society on Alcohol and other Drugs.

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. © The Author(s) 2012.

Cow milk consumption, insulin-like growth factor-I, and human biology: a life history approach.

PubMed

Wiley, Andrea S

2012-01-01

To assess the life history consequences of cow milk consumption at different stages in early life (prenatal to adolescence), especially with regard to linear growth and age at menarche and the role of insulin-like growth factor I (IGF-I) in mediating a relationship among milk, growth and development, and long-term biological outcomes. United States National Health and Nutrition Examination Survey (NHANES) data from 1999 to 2004 and review of existing literature. The literature tends to support milk's role in enhancing growth early in life (prior to age 5 years), but there is less support for this relationship during middle childhood. Milk has been associated with early menarche and with acceleration of linear growth in adolescence. NHANES data show a positive relationship between milk intake and linear growth in early childhood and adolescence, but not middle childhood, a period of relatively slow growth. IGF-I is a candidate bioactive molecule linking milk consumption to more rapid growth and development, although the mechanism by which it may exert such effects is unknown. Routine milk consumption is an evolutionarily novel dietary behavior that has the potential to alter human life history parameters, especially vis-à-vis linear growth, which in turn may have negative long-term biological consequences. Copyright © 2011 Wiley Periodicals, Inc.

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.

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

PubMed

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

2012-03-01

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

Early life trauma exposure and stress sensitivity in young children.

PubMed

Grasso, Damion J; Ford, Julian D; Briggs-Gowan, Margaret J

2013-01-01

The current study replicates and extends work with adults that highlights the relationship between trauma exposure and distress in response to subsequent, nontraumatic life stressors. The sample included 213 2-4-year-old children in which 64.3% had a history of potential trauma exposure. Children were categorized into 4 groups based on trauma history and current life stress. In a multivariate analysis of variance, trauma-exposed children with current life stressors had elevated internalizing and externalizing problems compared with trauma-exposed children without current stress and nontrauma-exposed children with and without current stressors. The trauma-exposed groups with or without current stressors did not differ on posttraumatic stress disorder symptom severity. Accounting for number of traumatic events did not change these results. These findings suggest that early life trauma exposure may sensitize young children and place them at risk for internalizing or externalizing problems when exposed to subsequent, nontraumatic life stressors.

Diverse Early Life-History Strategies in Migratory Amazonian Catfish: Implications for Conservation and Management

PubMed Central

Hegg, Jens C.; Giarrizzo, Tommaso; Kennedy, Brian P.

2015-01-01

Animal migrations provide important ecological functions and can allow for increased biodiversity through habitat and niche diversification. However, aquatic migrations in general, and those of the world’s largest fish in particular, are imperiled worldwide and are often poorly understood. Several species of large Amazonian catfish carry out some of the longest freshwater fish migrations in the world, travelling from the Amazon River estuary to the Andes foothills. These species are important apex predators in the main stem rivers of the Amazon Basin and make up the region’s largest fishery. They are also the only species to utilize the entire Amazon Basin to complete their life cycle. Studies indicate both that the fisheries may be declining due to overfishing, and that the proposed and completed dams in their upstream range threaten spawning migrations. Despite this, surprisingly little is known about the details of these species’ migrations, or their life history. Otolith microchemistry has been an effective method for quantifying and reconstructing fish migrations worldwide across multiple spatial scales and may provide a powerful tool to understand the movements of Amazonian migratory catfish. Our objective was to describe the migratory behaviors of the three most populous and commercially important migratory catfish species, Dourada (Brachyplatystoma rousseauxii), Piramutaba (Brachyplatystoma vaillantii), and Piraíba (Brachyplatystoma filamentosum). We collected fish from the mouth of the Amazon River and the Central Amazon and used strontium isotope signatures (87Sr/86Sr) recorded in their otoliths to determine the location of early rearing and subsequent. Fish location was determined through discriminant function classification, using water chemistry data from the literature as a training set. Where water chemistry data was unavailable, we successfully in predicted 87Sr/86Sr isotope values using a regression-based approach that related the geology of

Diverse Early Life-History Strategies in Migratory Amazonian Catfish: Implications for Conservation and Management.

PubMed

Hegg, Jens C; Giarrizzo, Tommaso; Kennedy, Brian P

2015-01-01

Animal migrations provide important ecological functions and can allow for increased biodiversity through habitat and niche diversification. However, aquatic migrations in general, and those of the world's largest fish in particular, are imperiled worldwide and are often poorly understood. Several species of large Amazonian catfish carry out some of the longest freshwater fish migrations in the world, travelling from the Amazon River estuary to the Andes foothills. These species are important apex predators in the main stem rivers of the Amazon Basin and make up the region's largest fishery. They are also the only species to utilize the entire Amazon Basin to complete their life cycle. Studies indicate both that the fisheries may be declining due to overfishing, and that the proposed and completed dams in their upstream range threaten spawning migrations. Despite this, surprisingly little is known about the details of these species' migrations, or their life history. Otolith microchemistry has been an effective method for quantifying and reconstructing fish migrations worldwide across multiple spatial scales and may provide a powerful tool to understand the movements of Amazonian migratory catfish. Our objective was to describe the migratory behaviors of the three most populous and commercially important migratory catfish species, Dourada (Brachyplatystoma rousseauxii), Piramutaba (Brachyplatystoma vaillantii), and Piraíba (Brachyplatystoma filamentosum). We collected fish from the mouth of the Amazon River and the Central Amazon and used strontium isotope signatures ((87)Sr/(86)Sr) recorded in their otoliths to determine the location of early rearing and subsequent. Fish location was determined through discriminant function classification, using water chemistry data from the literature as a training set. Where water chemistry data was unavailable, we successfully in predicted (87)Sr/(86)Sr isotope values using a regression-based approach that related the geology

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

Early-life stress and reproductive cost: A two-hit developmental model of accelerated aging?

PubMed

Shalev, Idan; Belsky, Jay

2016-05-01

Two seemingly independent bodies of research suggest a two-hit model of accelerated aging, one highlighting early-life stress and the other reproduction. The first, informed by developmental models of early-life stress, highlights reduced longevity effects of early adversity on telomere erosion, whereas the second, informed by evolutionary theories of aging, highlights such effects with regard to reproductive cost (in females). The fact that both early-life adversity and reproductive effort are associated with shorter telomeres and increased oxidative stress raises the prospect, consistent with life-history theory, that these two theoretical frameworks currently informing much research are tapping into the same evolutionary-developmental process of increased senescence and reduced longevity. Here we propose a mechanistic view of a two-hit model of accelerated aging in human females through (a) early-life adversity and (b) early reproduction, via a process of telomere erosion, while highlighting mediating biological embedding mechanisms that might link these two developmental aging processes. Copyright © 2016 Elsevier Ltd. All rights reserved.

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…

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.

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

Life histories in occupational therapy clinical practice.

PubMed

Frank, G

1996-04-01

This article defines and compares several narrative methods used to describe and interpret patients' lives. The biographical methods presented are case histories, life-charts, life histories, life stories, assisted autobiography, hermeneutic case reconstruction, therapeutic employment, volitional narratives, and occupational storytelling and story making. Emphasis is placed the clinician as a collaborator and interpreter of the patient's life through ongoing interactions and dialogue.

Primates and the evolution of long, slow life histories.

PubMed

Jones, James Holland

2011-09-27

Primates are characterized by relatively late ages at first reproduction, long lives and low fertility. Together, these traits define a life-history of reduced reproductive effort. Understanding the optimal allocation of reproductive effort, and specifically reduced reproductive effort, has been one of the key problems motivating the development of life-history theory. Because of their unusual constellation of life-history traits, primates play an important role in the continued development of life-history theory. In this review, I present the evidence for the reduced reproductive effort life histories of primates and discuss the ways that such life-history tactics are understood in contemporary theory. Such tactics are particularly consistent with the predictions of stochastic demographic models, suggesting a key role for environmental variability in the evolution of primate life histories. The tendency for primates to specialize in high-quality, high-variability food items may make them particularly susceptible to environmental variability and explains their low reproductive-effort tactics. I discuss recent applications of life-history theory to human evolution and emphasize the continuity between models used to explain peculiarities of human reproduction and senescence with the long, slow life histories of primates more generally. Copyright © 2011 Elsevier Ltd. All rights reserved.

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

Life-history evolution and the microevolution of intermediary metabolism: activities of lipid-metabolizing enzymes in life-history morphs of a wing-dimorphic cricket.

PubMed

Zera, Anthony J; Zhao, Zhangwu

2003-03-01

Although a considerable amount of information is available on the ecology, genetics, and physiology of life-history traits, much more limited data are available on the biochemical and genetic correlates of life-history variation within species. Specific activities of five enzymes of lipid biosynthesis and two enzymes of amino acid catabolism were compared among lines selected for flight-capable (LW[f]) versus flightless (SW) morphs of the cricket Gryllus firmus. These morphs, which exist in natural populations, differ genetically in ovarian growth (100-400% higher in SW) and aspects of flight capability including the size of wings and flight muscles, and the concentration of triglyceride flight fuel (40% greater in LW[f]). Consistently higher activity of each enzyme in LW(f) versus SW-selected lines, and strong co-segregation between morph and enzyme activity, demonstrated genetically based co-variance between wing morph and enzyme activity. Developmental profiles of enzyme activities strongly paralleled profiles of triglyceride accumulation during adulthood and previous measures of in vivo lipid biosynthesis. These data strongly imply that genetically based elevation in activities of lipogenic enzymes, and enzymes controlling the conversion of amino acids into lipids, is an important cause underlying the elevated accumulation of triglyceride in the LW(f) morph, a key biochemical component of the trade-off between elevated early fecundity and flight capability. Global changes in lipid and amino-acid metabolism appear to have resulted from microevolutionary alteration of regulators of metabolism. Finally, strong genotype x environment (diet) interactions were observed for most enzyme activities. Future progress in understanding the functional causes of life-history evolution requires a more detailed synthesis of the fields of life-history evolution and metabolic biochemistry. Wing polymorphism is a powerful experimental model in such integrative studies.

Early Life Exposures and Cancer

Cancer.gov

Early-life events and exposures have important consequences for cancer development later in life, however, epidemiological studies of early-life factors and cancer development later in life have had significant methodological challenges.

Effects of coal contamination on early life history processes of a reef-building coral, Acropora tenuis.

PubMed

Berry, Kathryn L E; Hoogenboom, Mia O; Brinkman, Diane L; Burns, Kathryn A; Negri, Andrew P

2017-01-15

Successful reproduction and larval dispersal are important for the persistence of marine invertebrate populations, and these early life history processes can be sensitive to marine pollution. Coal is emerging as a contaminant of interest due to the proximity of ports and shipping lanes to coral reefs. To assess the potential hazard of this contaminant, gametes, newly developed embryos, larvae and juveniles of the coral Acropora tenuis were exposed to a range of coal leachate, suspended coal, and coal smothering treatments. Fertilisation was the most sensitive reproductive process tested. Embryo survivorship decreased with increasing suspended coal concentrations and exposure duration, effects on larval settlement varied between treatments, while effects on juvenile survivorship were minimal. Leachate exposures had negligible effects on fertilisation and larval settlement. These results indicate that coral recruitment could be affected by spills that produce plumes of suspended coal particles which interact with gametes and embryos soon after spawning. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

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…

Nutrition shapes life-history evolution across species

PubMed Central

Swanson, Eli M.; Espeset, Anne; Mikati, Ihab; Bolduc, Isaac; Kulhanek, Robert; White, William A.; Kenzie, Susan

2016-01-01

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

Life-history trade-offs mediate 'personality' variation in two colour morphs of the pea aphid, Acyrthosiphon pisum.

PubMed

Schuett, Wiebke; Dall, Sasha R X; Kloesener, Michaela H; Baeumer, Jana; Beinlich, Felix; Eggers, Till

2015-01-01

Life-history trade-offs are considered a major driving force in the emergence of consistent behavioural differences (personality variation); but empirical tests are scarce. We investigated links between a personality trait (escape response), life-history and state variables (growth rate, size and age at first reproduction, age-dependent reproductive rates, lifetime reproductive success, life span) in red and green colour morphs of clonal pea aphids, Acyrthosiphon pisum. Escape response (dropping/non-dropping off a plant upon a predatory attack) was measured repeatedly to classify individuals as consistent droppers, consistent nondroppers or inconsistents. Red morphs experienced stronger trade-offs between early reproduction and life span than green morphs; and red consistent (non)droppers had highest lifetime reproductive success. Red droppers followed a risk-averse life-history strategy (high late reproduction), red nondroppers a risk-prone strategy (high early reproduction), while reproductive rates were equivalent for all green behavioural types and red inconsistents. This suggests that red morphs suffer the highest costs of dropping (they are most conspicuous to predators), which 'equivalates' fitness payoffs to both risk-takers (red non-droppers) and risk-averse red droppers. The strong trade-off also means that committing to a particular lifestyle (being consistent) maximises fitness. Our study suggests that life-history trade-offs likely mediate personality variation but effects might depend on interactions with other organismal characteristics (here: colour morph). © 2014 The Authors. Journal of Animal Ecology © 2014 British Ecological Society.

Falls, sarcopenia and growth in early life

PubMed Central

Sayer, Avan Aihie; Syddall, Holly E; Martin, Helen J; Dennison, Elaine M; Anderson, Frazer H; Cooper, Cyrus

2007-01-01

Recent studies have shown that people with poor early growth have an increased risk of sarcopenia. Sarcopenia is an important risk factor for falls but it is not known whether poor early growth is related to falls. We investigated this in the Hertfordshire Cohort Study where 2148 participants completed a falls history. Grip strength was used as a marker of sarcopenia. Birth weight, weight at one year and conditional infant growth were analysed in relation to falls history. The prevalence of any fall in the last year was 14.3% for men and 22.5% for women. Falls in the last year were inversely related to adult grip strength, height and walking speed in men and women as well as to lower conditional infant growth in men (OR 1.27 [95% CI 1.04, 1.56] per SD decrease in conditional infant growth, p=0.02). This association was attenuated after adjustment for grip strength. Our findings support an association between poor early growth and falls in older men which appears to be mediated partly through sarcopenia. The lack of relationship with birth weight suggests that postnatal rather than prenatal influences on muscle growth and development may be important for risk of falls in later life. PMID:16905644

GENOMIC BASIS OF AGING AND LIFE HISTORY EVOLUTION IN DROSOPHILA MELANOGASTER

PubMed Central

Remolina, Silvia C.; Chang, Peter L.; Leips, Jeff; Nuzhdin, Sergey V.; Hughes, Kimberly A.

2015-01-01

Natural diversity in aging and other life history patterns is a hallmark of organismal variation. Related species, populations, and individuals within populations show genetically based variation in life span and other aspects of age-related performance. Population differences are especially informative because these differences can be large relative to within-population variation and because they occur in organisms with otherwise similar genomes. We used experimental evolution to produce populations divergent for life span and late-age fertility and then used deep genome sequencing to detect sequence variants with nucleotide-level resolution. Several genes and genome regions showed strong signatures of selection, and the same regions were implicated in independent comparisons, suggesting that the same alleles were selected in replicate lines. Genes related to oogenesis, immunity, and protein degradation were implicated as important modifiers of late-life performance. Expression profiling and functional annotation narrowed the list of strong candidate genes to 38, most of which are novel candidates for regulating aging. Life span and early-age fecundity were negatively correlated among populations; therefore the alleles we identified also are candidate regulators of a major life-history trade-off. More generally, we argue that hitchhiking mapping can be a powerful tool for uncovering the molecular bases of quantitative genetic variation. PMID:23106705

Mercury's Early Geologic History

NASA Astrophysics Data System (ADS)

Denevi, B. W.; Ernst, C. M.; Klima, R. L.; Robinson, M. S.

2018-05-01

A combination of geologic mapping, compositional information, and geochemical models are providing a better understanding of Mercury's early geologic history, and allow us to place it in the context of the Moon and the terrestrial planets.

An Ecological Analysis of the Effects of Deviant Peer Clustering on Sexual Promiscuity, Problem Behavior, and Childbearing from Early Adolescence to Adulthood: An Enhancement of the Life History Framework

ERIC Educational Resources Information Center

Dishion, Thomas J.; Ha, Thao; Veronneau, Marie-Helene

2012-01-01

The authors propose that peer relationships should be included in a life history perspective on adolescent problem behavior. Longitudinal analyses were used to examine deviant peer clustering as the mediating link between attenuated family ties, peer marginalization, and social disadvantage in early adolescence and sexual promiscuity in middle…

Bipolar affective disorder and borderline personality disorder: Differentiation based on the history of early life stress and psychoneuroendocrine measures.

PubMed

Mazer, Angela Kaline; Cleare, Anthony J; Young, Allan H; Juruena, Mario F

2018-04-24

Borderline Personality Disorder (BPD) and Bipolar Affective Disorder (BD) have clinical characteristics in common which often make their differential diagnosis difficult. The history of early life stress (ELS) may be a differentiating factor between BPD and BD, as well as its association with clinical manifestations and specific neuroendocrine responses in each of these diagnoses. Assessing and comparing patients with BD and BPD for factors related to symptomatology, etiopathogenesis and neuroendocrine markers. The study sample consisted of 51 women, divided into 3 groups: patients with a clinical diagnosis of BPD (n = 20) and BD (n = 16) and healthy controls (HC, n = 15). Standardized instruments were used for the clinical evaluation, while the history of ELS was quantified with the Childhood Trauma Questionnaire (CTQ), and classified according to the subtypes: emotional abuse, physical abuse, sexual abuse, emotional neglect and physical neglect. The functioning of the hypothalamic-pituitary-adrenal (HPA) axis was evaluated by measuring a single plasma cortisol sample. Patients with BPD presented with more severe psychiatric symptoms of: anxiety, impulsivity, depression, hopelessness and suicidal ideation than those with BD. The history of ELS was identified as significantly more prevalent and more severe in patients (BPD and BP) than in HC. Emotional abuse, emotional neglect and physical neglect also showed differences and were higher in BPD than BD patients. BPD patients had greater severity of ELS overall and in the subtypes of emotional abuse, emotional neglect and physical neglect than BD patients. The presence of ELS in patients with BPD and BP showed significant difference with lower cortisol levels when compared to HC. The endocrine evaluation showed no significant differences between the diagnoses of BPD and BD. Cortisol measured in patients with BPD was significantly lower compared to HC in the presence of emotional neglect and physical

Captive propagation, reproductive biology, and early life history of the Diamond Darter (Crystallaria cincotta)

USGS Publications Warehouse

Ruble, Crystal L.; Rakes, Patrick L.; Shute, John R.; Welsh, Stuart A.

2014-01-01

Reproductive biology and early life history data are critical for the conservation and management of rare fishes. During 2008–2012 a captive propagation study was conducted on the Diamond Darter, Crystallaria cincotta, a rare species with a single extant population in the lower Elk River, West Virginia. Water temperatures during spawning ranged from 11.1–23.3 C. Females and males spawned with quick vibrations, burying eggs in fine sand in relatively swift clean depositional areas. Egg size was 1.8–1.9 mm, and embryos developed within 7 to 11 d. Diamond Darters were 6.7–7.2 mm total length (TL) at hatch. Larvae ranged from 9.0–11.0 mm TL following a 5–10 d period of yolk sac absorption. Larvae had relatively large mouth gapes and teeth and were provided brine shrimp Artemia sp., Ceriodaphnia dubia neonates, marine Brachionus rotifers, and powdered foods (50–400 µm) but did not appear to feed in captivity, except for one observation of larval cannibalization. Larvae survived for a maximum of 10 d. To increase larval survival and reduce the possibility of cannibalism, other alternative food sources are needed during captive propagation.

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

PubMed

Cabeza de Baca, Tomás; Ellis, Bruce J

2017-06-01

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

Family Environments, Adrenarche, and Sexual Maturation: A Longitudinal Test of a Life History Model

ERIC Educational Resources Information Center

Ellis, Bruce J.; Essex, Marilyn J.

2007-01-01

Life history theorists have proposed that humans have evolved to be sensitive to specific features of early childhood environments and that exposure to different environments biases children toward development of different reproductive strategies, including differential pubertal timing. The current research provides a longitudinal test of this…

Early-late life trade-offs and the evolution of ageing in the wild.

PubMed

Lemaître, Jean-François; Berger, Vérane; Bonenfant, Christophe; Douhard, Mathieu; Gamelon, Marlène; Plard, Floriane; Gaillard, Jean-Michel

2015-05-07

Empirical evidence for declines in fitness components (survival and reproductive performance) with age has recently accumulated in wild populations, highlighting that the process of senescence is nearly ubiquitous in the living world. Senescence patterns are highly variable among species and current evolutionary theories of ageing propose that such variation can be accounted for by differences in allocation to growth and reproduction during early life. Here, we compiled 26 studies of free-ranging vertebrate populations that explicitly tested for a trade-off between performance in early and late life. Our review brings overall support for the presence of early-late life trade-offs, suggesting that the limitation of available resources leads individuals to trade somatic maintenance later in life for high allocation to reproduction early in life. We discuss our results in the light of two closely related theories of ageing-the disposable soma and the antagonistic pleiotropy theories-and propose that the principle of energy allocation roots the ageing process in the evolution of life-history strategies. Finally, we outline research topics that should be investigated in future studies, including the importance of natal environmental conditions in the study of trade-offs between early- and late-life performance and the evolution of sex-differences in ageing patterns. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Re-experiencing Violence across the Life Course: Histories of Childhood Maltreatment and Elder Abuse Victimization.

PubMed

Kong, Jooyoung; Easton, Scott D

2018-03-26

This study primarily examines the associations between histories of childhood maltreatment (i.e., neglect, emotional, physical, and sexual abuse) and elder abuse victimization and explores whether gender moderates the associations. We conducted a secondary data analysis of 5,968 older adults (mean age = 71 years) based on data from the Wisconsin Longitudinal Study (2010-2011). Using retrospective self-reports of childhood and current (past 12 months) victimization experiences, logistic regression analyses were conducted to estimate the effects of early-life adversities on the likelihood of elder abuse victimization. Results indicate that childhood emotional abuse and childhood sexual abuse were associated with greater risk of being abused as older adults, after controlling for childhood and adult background factors. We also found that the effect of childhood sexual abuse on elder abuse victimization was weaker for women than men. Findings suggest that the phenomenon of revictimization may occur not only in early and middle adulthood, but also in late life. To advance our understanding of victimization across the life course, future research on root causes of elder abuse should include histories of child abuse.

Life history diversity in Klamath River steelhead

USGS Publications Warehouse

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

2016-01-01

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

Neuroethology and life history adaptations of the elasmobranch electric sense.

PubMed

Sisneros, Joseph A; Tricas, Timothy C

2002-01-01

The electric sense of elasmobranch fishes (sharks and rays) is an important sensory modality known to mediate the detection of bioelectric stimuli. Although the best known function for the use of the elasmobranch electric sense is prey detection, relatively few studies have investigated other possible biological functions. Here, we review recent studies that demonstrate the elasmobranch electrosensory system functions in a wide number of behavioral contexts including social, reproductive and anti-predator behaviors. Recent work on non-electrogenic stingrays demonstrates that the electric sense is used during reproduction and courtship for conspecific detection and localization. Electrogenic skates may use their electrosensory encoding capabilities and electric organ discharges for communication during social and reproductive interactions. The electric sense may also be used to detect and avoid predators during early life history stages in many elasmobranch species. Embryonic clearnose skates demonstrate a ventilatory freeze response when a weak low-frequency electric field is imposed upon the egg capsule. Peak frequency sensitivity of the peripheral electrosensory system in embryonic skates matches the low frequencies of phasic electric stimuli produced by natural fish egg-predators. Neurophysiology experiments reveal that electrosensory tuning changes across the life history of a species and also seasonally due to steroid hormone changes during the reproductive season. We argue that the ontogenetic and seasonal variation in electrosensory tuning represent an adaptive electrosensory plasticity that may be common to many elasmobranchs to enhance an individual's fitness throughout its life history.

Late Life Employment Histories and Their Association With Work and Family Formation During Adulthood: A Sequence Analysis Based on ELSA.

PubMed

Wahrendorf, Morten; Zaninotto, Paola; Hoven, Hanno; Head, Jenny; Carr, Ewan

2017-05-31

To extend research on workforce participation beyond age 50 by describing entire employment histories in later life and testing their links to prior life course conditions. We use data from the English Longitudinal Study of Ageing, with retrospective information on employment histories between age 50 and 70 for 1,103 men and 1,195 women (n = 2,298). We apply sequence analysis and group respondents into eight clusters with similar histories. Using multinomial regressions, we then test their links to labor market participation, partnership, and parenthood histories during early (age 20-34) and mid-adulthood (age 35-49). Three clusters include histories dominated by full-time employees but with varying age of retirement (before, at, and after age 60). One cluster is dominated by self-employment with comparatively later retirement. Remaining clusters include part-time work (retirement around age 60 or no retirement), continuous domestic work (mostly women), or other forms of nonemployment. Those who had strong attachments to the labor market during adulthood are more likely to have histories of full-time work up until and beyond age 60, especially men. Parenthood in early adulthood is related to later retirement (for men only). Continued domestic work was not linked to parenthood. Partnered women tend to work part-time or do domestic work. The findings remain consistent after adjusting for birth cohort, childhood adversity, life course health, and occupational position. Policies aimed at increasing the proportion of older workers not only need to address later stages of the life course but also early and mid-adulthood. © The Author 2017. Published by Oxford University Press on behalf of The Gerontological Society of America.

Life-history tactics: a review of the ideas.

PubMed

Stearns, S C

1976-03-01

This review organizes ideas on the evolution of life histories. The key life-history traits are brood size, size of young, the age distribution of reproductive effort, the interaction of reproductive effort with adult mortality, and the variation in these traits among an individual's progeny. The general theoretical problem is to predict which combinations of traits will evolve in organisms living in specified circumstances. First consider single traits. Theorists have made the following predictions: (1) Where adult exceeds juvenile mortality, the organism should reproduce only once in its lifetime. Where juvenile exceeds adult mortality, the organism should reproduce several times. (2) Brood size should macimize the number of young surviving to maturity, summed over the lifetime of the parent. But when optimum brood-size unpredictably in time, smaller broods should be favored because they decrease the chances of total failure on a given attempt. (3) In expanding populations, selection should minimize age at maturity. In stable populations, when reproductive success depends on size, age, or social status, or when adult exceeds juvenile mortality, then maturation should be delayed, as it should be in declining populations. (4) Young should increase in size at birth with increased predation risk, and decrease in size with increased resource availability. Theorists have also predicted that only particular combinations of traits should occur in specified circumstances. (5) In growing populations, age at maturity should be minimized, reproductive effort concentrated early in life, and brood size increased. (6) One view holds that in stable environments, late maturity, broods, a few, large young, parental care, and small reproductive efforts should be favored (K-selection). In fluctuating environments, early maturity, many small young, reduced parental care, and large reproductive efforts should be favored (r-selection). (7) But another view holds that when juvenile

Oral Life Histories of One-Room Schoolhouse Teachers: Voices from the Recitation Bench.

ERIC Educational Resources Information Center

Duling, Gretchen A.

This book examines Gallia County (Ohio) one-room schools through the oral life histories of 14 retired female teachers. Interviews with the teachers focused on conditions and practices in one-room schoolhouses in the early to mid-20th century in rural southeastern Ohio, and on the common characteristics of one-room school teachers who became rural…

Genetic and life-history consequences of extreme climate events

PubMed Central

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

2017-01-01

Climate change is predicted to increase the frequency and intensity of extreme climate events. Tests on empirical data of theory-based predictions on the consequences of extreme climate events are thus necessary to understand the adaptive potential of species and the overarching risks associated with all aspects of climate change. We tested predictions on the genetic and life-history consequences of extreme climate events in two populations of marble trout Salmo marmoratus that have experienced severe demographic bottlenecks due to flash floods. We combined long-term field and genotyping data with pedigree reconstruction in a theory-based framework. Our results show that after flash floods, reproduction occurred at a younger age in one population. In both populations, we found the highest reproductive variance in the first cohort born after the floods due to a combination of fewer parents and higher early survival of offspring. A small number of parents allowed for demographic recovery after the floods, but the genetic bottleneck further reduced genetic diversity in both populations. Our results also elucidate some of the mechanisms responsible for a greater prevalence of faster life histories after the extreme event. PMID:28148745

Genetic and life-history consequences of extreme climate events.

PubMed

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

2017-02-08

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

Patterns of larval source distribution and mixing in early life stages of Pacific cod (Gadus macrocephalus) in the southeastern Bering Sea

NASA Astrophysics Data System (ADS)

Miller, Jessica A.; DiMaria, Ruth A.; Hurst, Thomas P.

2016-12-01

Effective and sustainable management depends on knowledge of spawning locations and their relative contributions to marine fish populations. Pacific cod (Gadus macrocephalus) in the southeastern Bering Sea aggregate at discrete spawning locations but there is little information on patterns of larval dispersal and the relative contribution of specific spawning areas to nursery habitats. Age-0 Pacific cod from two cohorts (2006 and 2008) were examined to address the following questions: (1) does size, age, and otolith chemistry vary among known capture locations; (2) can variation in elemental composition of the otolith cores (early larval signatures) be used to infer the number of chemically distinct sources contributing to juvenile recruits in the Bering Sea; and (3) to what extent are juvenile collection locations represented by groups of fish with similar chemical histories throughout their early life history? Hierarchical cluster (HCA) and discriminant function analyses (DFA) were used to examine variation in otolith chemistry at discrete periods throughout the early life history. HCA identified five chemically distinct groups of larvae in the 2006 cohort and three groups in 2008; however, three sources accounted for 80-100% of the juveniles in each year. DFA of early larval signatures indicated that there were non-random spatial distributions of early larvae in both years, which may reflect interannual variation in regional oceanography. There was also a detectable and substantial level of coherence in chemical signatures within groups of fish throughout the early life history. The variation in elemental signatures throughout the early life history (hatch to capture) indicates that otolith chemical analysis could be an effective tool to further clarify larval sources and dispersal, identify juvenile nursery habitats, and estimate the contributions of juvenile nursery habitats to the adult population within the southeastern Bering Sea.

Bayesian analysis of the astrobiological implications of life's early emergence on Earth.

PubMed

Spiegel, David S; Turner, Edwin L

2012-01-10

Life arose on Earth sometime in the first few hundred million years after the young planet had cooled to the point that it could support water-based organisms on its surface. The early emergence of life on Earth has been taken as evidence that the probability of abiogenesis is high, if starting from young Earth-like conditions. We revisit this argument quantitatively in a bayesian statistical framework. By constructing a simple model of the probability of abiogenesis, we calculate a bayesian estimate of its posterior probability, given the data that life emerged fairly early in Earth's history and that, billions of years later, curious creatures noted this fact and considered its implications. We find that, given only this very limited empirical information, the choice of bayesian prior for the abiogenesis probability parameter has a dominant influence on the computed posterior probability. Although terrestrial life's early emergence provides evidence that life might be abundant in the universe if early-Earth-like conditions are common, the evidence is inconclusive and indeed is consistent with an arbitrarily low intrinsic probability of abiogenesis for plausible uninformative priors. Finding a single case of life arising independently of our lineage (on Earth, elsewhere in the solar system, or on an extrasolar planet) would provide much stronger evidence that abiogenesis is not extremely rare in the universe.

Primate energy expenditure and life history

PubMed Central

Pontzer, Herman; Raichlen, David A.; Gordon, Adam D.; Schroepfer-Walker, Kara K.; Hare, Brian; O’Neill, Matthew C.; Muldoon, Kathleen M.; Dunsworth, Holly M.; Wood, Brian M.; Isler, Karin; Burkart, Judith; Irwin, Mitchell; Shumaker, Robert W.; Lonsdorf, Elizabeth V.; Ross, Stephen R.

2014-01-01

Humans and other primates are distinct among placental mammals in having exceptionally slow rates of growth, reproduction, and aging. Primates’ slow life history schedules are generally thought to reflect an evolved strategy of allocating energy away from growth and reproduction and toward somatic investment, particularly to the development and maintenance of large brains. Here we examine an alternative explanation: that primates’ slow life histories reflect low total energy expenditure (TEE) (kilocalories per day) relative to other placental mammals. We compared doubly labeled water measurements of TEE among 17 primate species with similar measures for other placental mammals. We found that primates use remarkably little energy each day, expending on average only 50% of the energy expected for a placental mammal of similar mass. Such large differences in TEE are not easily explained by differences in physical activity, and instead appear to reflect systemic metabolic adaptation for low energy expenditures in primates. Indeed, comparisons of wild and captive primate populations indicate similar levels of energy expenditure. Broad interspecific comparisons of growth, reproduction, and maximum life span indicate that primates’ slow metabolic rates contribute to their characteristically slow life histories. PMID:24474770

Depression is an independent determinant of life satisfaction early after stroke.

PubMed

Oosterveer, Daniëlla M; Mishre, Radha Rambaran; van Oort, Andrea; Bodde, Karin; Aerden, Leo A M

2017-03-06

Life satisfaction is reduced in stroke patients. However, as a rule, rehabilitation goals are not aimed at life satisfaction, but at activities and participation. In order to optimize life satisfaction in stroke patients, rehabilitation should take into account the determinants of life satisfaction. The aim of this study was therefore to determine what factors are independent determinants of life satisfaction in a large group of patients early after stroke. Stroke-surviving patients were examined by a specialized nurse 6 weeks after discharge from hospital or rehabilitation setting. A standardized history and several screening lists, including the Lisat-9, were completed. Step-wise regression was used to identify independent determinants of life satisfaction. A total of 284 stroke-surviving patients were included in the study. Of these, 117 answered all of the Lisat-9 questions. Most patients (66.5%) rated their life as a whole as "satisfying" or "very satisfying". More depressive symptoms were independently associated with lower life satisfaction (p < 0.001). Most stroke-surviving patients are satisfied with their life early after a stroke. The score on the Hospital Anxiety and Depression Scale depression items is independently associated with life satisfaction. Physicians should therefore pay close attention to the mood of these patients.

Psychoneuroimmunology of Early-Life Stress: The Hidden Wounds of Childhood Trauma?

PubMed Central

Danese, Andrea; J Lewis, Stephanie

2017-01-01

The brain and the immune system are not fully formed at birth, but rather continue to mature in response to the postnatal environment. The two-way interaction between the brain and the immune system makes it possible for childhood psychosocial stressors to affect immune system development, which in turn can affect brain development and its long-term functioning. Drawing from experimental animal models and observational human studies, we propose that the psychoneuroimmunology of early-life stress can offer an innovative framework to understand and treat psychopathology linked to childhood trauma. Early-life stress predicts later inflammation, and there are striking analogies between the neurobiological correlates of early-life stress and of inflammation. Furthermore, there are overlapping trans-diagnostic patterns of association of childhood trauma and inflammation with clinical outcomes. These findings suggest new strategies to remediate the effect of childhood trauma before the onset of clinical symptoms, such as anti-inflammatory interventions and potentiation of adaptive immunity. Similar strategies might be used to ameliorate the unfavorable treatment response described in psychiatric patients with a history of childhood trauma. PMID:27629365

The relationship between age of onset and risk factors including family history and life style in Korean population with type 2 diabetes mellitus.

PubMed

Noh, Jin-Won; Jung, Jin Hee; Park, Jeong Eun; Lee, Jung Hwa; Sim, Kang Hee; Park, Jumin; Kim, Min Hee; Yoo, Ki-Bong

2018-02-01

[Purpose] The purpose of the present study was to assess the relationship between age of onset and risk factors including family history and life style in Korean population with type 2 diabetes mellitus (T2D). [Subjects and Methods] Subjects with T2D patients who received outpatient care for blood sugar control were randomly sampled at 13 general hospitals and 969 subjects were included. Cox proportional hazard models were used to confirm associations between age of onset and risk factors including family history and life style in Korean population with T2D. [Results] Parent history of T2D was significantly associated with age of onset. Compared to none of family members with T2D, those whose both father and mother had a history showed the highest the risk of early-onset (HR=2.36; 95% CI=1.45-3.85). Mother and father's history of T2D (HR=1.73; 95% CI=1.46-2.05; HR=1.83; 95% CI=1.40-2.37) were associated with the risk of early-onset. Moreover, exercise (HR=1.23, CI=1.08-1.40) smoking status (HR=1.62, CI=1.32-1.99), and drinking (HR=1.32, CI=1.13-1.54) were associated with a higher risk for the early-onset. [Conclusion] Family history as well as life style including exercise, smoking, and drinking are the risk factors for early-onset factor in Korean population with T2D.

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.

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

Pathogen and host genotype differently affect pathogen fitness through their effects on different life-history stages.

PubMed

Bruns, Emily; Carson, Martin; May, Georgiana

2012-08-02

Adaptation of pathogens to their hosts depends critically on factors affecting pathogen reproductive rate. While pathogen reproduction is the end result of an intricate interaction between host and pathogen, the relative contributions of host and pathogen genotype to variation in pathogen life history within the host are not well understood. Untangling these contributions allows us to identify traits with sufficient genetic variation for selection to act and to identify mechanisms of coevolution between pathogens and their hosts. We investigated the effects of pathogen and host genotype on three life-history components of pathogen fitness; infection efficiency, latent period, and sporulation capacity, in the oat crown rust fungus, Puccinia coronata f.sp. avenae, as it infects oats (Avena sativa). We show that both pathogen and host genotype significantly affect total spore production but do so through their effects on different life-history stages. Pathogen genotype has the strongest effect on the early stage of infection efficiency, while host genotype most strongly affects the later life-history stages of latent period and sporulation capacity. In addition, host genotype affected the relationship between pathogen density and the later life-history traits of latent period and sporulation capacity. We did not find evidence of pathogen-by-host genotypic (GxG) interactions. Our results illustrate mechanisms by which variation in host populations will affect the evolution of pathogen life history. Results show that different pathogen life-history stages have the potential to respond differently to selection by host or pathogen genotype and suggest mechanisms of antagonistic coevolution. Pathogen populations may adapt to host genotypes through increased infection efficiency while their plant hosts may adapt by limiting the later stages of pathogen growth and spore production within the host.

High early life mortality in free-ranging dogs is largely influenced by humans

PubMed Central

Paul, Manabi; Sen Majumder, Sreejani; Sau, Shubhra; Nandi, Anjan K.; Bhadra, Anindita

2016-01-01

Free-ranging dogs are a ubiquitous part of human habitations in many developing countries, leading a life of scavengers dependent on human wastes for survival. The effective management of free-ranging dogs calls for understanding of their population dynamics. Life expectancy at birth and early life mortality are important factors that shape life-histories of mammals. We carried out a five year-long census based study in seven locations of West Bengal, India, to understand the pattern of population growth and factors affecting early life mortality in free-ranging dogs. We observed high rates of mortality, with only ~19% of the 364 pups from 95 observed litters surviving till the reproductive age; 63% of total mortality being human influenced. While living near people increases resource availability for dogs, it also has deep adverse impacts on their population growth, making the dog-human relationship on streets highly complex. PMID:26804633

Building an Evidence-Based Mental Health Program for Children with History of Early Adversity

ERIC Educational Resources Information Center

Kroupina, Maria; Vermeulen, Marlous; Moberg, Stephanie

2015-01-01

Adoption is a major intervention in a child's life, however internationally adopted (IA) children remain at risk for long-term neurodevelopmental and mental health issues due to the fact that most of them have a history of early adversity prior to their adoption. In the last 20 years, extensive research with this population has increased the…

Biologic History and the Cardinal Rule of Life

NASA Astrophysics Data System (ADS)

Schopf, J. W.

2004-12-01

,000 Ma ago, they first evolved slowly -- following the Cardinal Rule of Life -- until ˜1,000 Ma ago when sexual reproduction took over. This development markedly speeded the development of new species that could compete, and eventually dominate, in habitats previously owned by their non-sexual prokaryotic ancestors, as evidenced both in the fossil record and by molecular biology-based rRNA phylogenetic trees. The third innovation was cellular differentiation and multicelluarity. Although the "Cambrian Explosion" -- the great radiation of animal life during the Cambrian Period beginning ˜550 Ma ago -- is commonly viewed as reflecting this event, it seems more a continuum than a step-function change. Evolution speeded in the half-billion years between 1,000 Ma ago and the beginning of the Cambrian: phytoplankton gave rise to multicellular seaweeds by ˜850 Ma; and primitive protozoans, present as early as ˜950 Ma, had by ˜600 Ma given rise to soft-bodied multicelled animals. Soon thereafter, animals developed shelly protective armor -- marking the beginning of the Cambrian Period, and thus of the Phanerozoic Eon. The Phanerozoic history of life is familiar to all, from spore-producing to seed-producing to flowering plants, from animals without backbones to fish, land-dwelling vertebrates, then birds and mammals. Plants ("eatees") and animals ("eaters") co-evolved in sequence. Again, life followed the Cardinal Rule, changing little, then evolving rapidly, as new ecologic opportunities became available.

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

PubMed

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

2010-09-23

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

Academic Oral History: Life Review in Spite of Itself.

ERIC Educational Resources Information Center

Ryant, Carl

The process and content of the life review should not be separated from the creation of an oral history. Several projects, undertaken at the University of Louisville Oral History Center, support the therapeutic aspects of reminiscence. The dichotomy between oral history, as an historical database, and life review, as a therapeutic exercise, breaks…

Phenological sequences reveal aggregate life history response to climatic warming.

PubMed

Post, Eric S; Pedersen, Christian; Wilmers, Christopher C; Forchhammer, Mads C

2008-02-01

Climatic warming is associated with organisms breeding earlier in the season than is typical for their species. In some species, however, response to warming is more complex than a simple advance in the timing of all life history events preceding reproduction. Disparities in the extent to which different components of the reproductive phenology of organisms vary with climatic warming indicate that not all life history events are equally responsive to environmental variation. Here, we propose that our understanding of phenological response to climate change can be improved by considering entire sequences of events comprising the aggregate life histories of organisms preceding reproduction. We present results of a two-year warming experiment conducted on 33 individuals of three plant species inhabiting a low-arctic site. Analysis of phenological sequences of three key events for each species revealed how the aggregate life histories preceding reproduction responded to warming, and which individual events exerted the greatest influence on aggregate life history variation. For alpine chickweed (Cerastium alpinum), warming elicited a shortening of the duration of the emergence stage by 2.5 days on average, but the aggregate life history did not differ between warmed and ambient plots. For gray willow (Salix glauca), however, all phenological events monitored occurred earlier on warmed than on ambient plots, and warming reduced the aggregate life history of this species by 22 days on average. Similarly, in dwarf birch (Betula nana), warming advanced flower bud set, blooming, and fruit set and reduced the aggregate life history by 27 days on average. Our approach provides important insight into life history responses of many organisms to climate change and other forms of environmental variation. Such insight may be compromised by considering changes in individual phenological events in isolation.

Beyond Cumulative Risk: Distinguishing Harshness and Unpredictability as Determinants of Parenting and Early Life History Strategy

ERIC Educational Resources Information Center

Belsky, Jay; Schlomer, Gabriel L.; Ellis, Bruce J.

2012-01-01

Drawing on life history theory, Ellis and associates' (2009) recent across- and within-species analysis of ecological effects on reproductive development highlighted two fundamental dimensions of environmental variation and influence: harshness and unpredictability. To evaluate the unique contributions of these factors, the authors of present…

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. Copyright © 2015, American Association for the Advancement of Science.

Root colonization dynamics of two ectomycorrhizal fungi of contrasting life history strategies are mediated by

Treesearch

Erik A. Lilleskov; Thomas D. Bruns

2003-01-01

-Here we investigated whether root colonization dynamics of ectomycorrhizal fungi (EMF) of contrasting life history strategies (i.e. early vs late successional dominants) were affected by resource availability, as mediated either directly via the soil, or indirectly via host nutrition. -In a two phase experiment, Pinusm muricata seedlings were co-...

Risk factors for alcoholism in the Oklahoma Family Health Patterns project: impact of early life adversity and family history on affect regulation and personality.

PubMed

Sorocco, Kristen H; Carnes, Nathan C; Cohoon, Andrew J; Vincent, Andrea S; Lovallo, William R

2015-05-01

This study examined the impact of early lifetime adversity (ELA) on affect regulation and personality in persons with family history (FH+) and without (FH-) a family history of alcoholism. We examined the impact of early life adversity in healthy young adults, 18-30 years of age enrolled in a long-term study on risk for alcohol and other substance abuse. ELA was assessed by a composite score of low socioeconomic status and personal experience of physical or sexual abuse and/or separation from parents before age 16, resulting in a score of 0, 1-2, or >3 adverse events. Unstable affect regulation and personality variables were obtained via self-report measures. Higher ELA scores were seen in FH+ (χ(2)=109.2, p<0.0001) and in women (χ(2)=17.82, p=0.0019). Although higher ELA predicted less emotional stability and more behavioral undercontrol, further analysis including both FH and ELA showed that FH+ persons are prone to poor affect regulation, negative moods, and have risky drinking and drug abuse tendencies independent of ELA level. ELA predicts reduced stress reactivity and poorer cognitive control over impulsive behaviors as shown elsewhere. The present work shows that FH+ have poor mood regulation and antisocial characteristics. The greater prevalence of ELA in FH+ persons indicates that life experience and FH+ work in tandem to result in risky patterns of alcohol and drug experimentation to elevate risk for alcoholism. Further studies of genetic and environmental contributions to alcoholism are called for. Published by Elsevier Ireland Ltd.

Predicting Later-Life Outcomes of Early-Life Exposures

EPA Science Inventory

Background: In utero exposure of the fetus to a stressor can lead to disease in later life. Epigenetic mechanisms are likely mediators of later-life expression of early-life events.Objectives: We examined the current state of understanding of later-life diseases resulting from ea...

The relationship between age of onset and risk factors including family history and life style in Korean population with type 2 diabetes mellitus

PubMed Central

Noh, Jin-Won; Jung, Jin Hee; Park, Jeong Eun; Lee, Jung Hwa; Sim, Kang Hee; Park, Jumin; Kim, Min Hee; Yoo, Ki-Bong

2018-01-01

[Purpose] The purpose of the present study was to assess the relationship between age of onset and risk factors including family history and life style in Korean population with type 2 diabetes mellitus (T2D). [Subjects and Methods] Subjects with T2D patients who received outpatient care for blood sugar control were randomly sampled at 13 general hospitals and 969 subjects were included. Cox proportional hazard models were used to confirm associations between age of onset and risk factors including family history and life style in Korean population with T2D. [Results] Parent history of T2D was significantly associated with age of onset. Compared to none of family members with T2D, those whose both father and mother had a history showed the highest the risk of early-onset (HR=2.36; 95% CI=1.45–3.85). Mother and father’s history of T2D (HR=1.73; 95% CI=1.46–2.05; HR=1.83; 95% CI=1.40–2.37) were associated with the risk of early-onset. Moreover, exercise (HR=1.23, CI=1.08–1.40) smoking status (HR=1.62, CI=1.32–1.99), and drinking (HR=1.32, CI=1.13–1.54) were associated with a higher risk for the early-onset. [Conclusion] Family history as well as life style including exercise, smoking, and drinking are the risk factors for early-onset factor in Korean population with T2D. PMID:29545678

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.

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

PubMed

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

2017-01-01

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

Exploring life history characteristics of naturalized versus stocked chinook

USGS Publications Warehouse

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

2011-01-01

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

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…

Learning History in Early Childhood: Teaching Methods and Children's Understanding

ERIC Educational Resources Information Center

Skjaeveland, Yngve

2017-01-01

This article discusses the teaching of history in early childhood education and care centres and children's understanding of history. Based on interviews with eight Norwegian early childhood education and care teachers and on interpretative phenomenological analysis, the article shows how the early childhood education and care centres teach…

Biodemography of Exceptional Longevity: Early-life and Mid-life predictors of Human Longevity

PubMed Central

Gavrilov, Leonid A.; Gavrilova, Natalia S.

2011-01-01

Effects of early-life and middle-life conditions on exceptional longevity are explored in this study using two matched case-control studies. The first study compares 198 validated centenarians born in the United States in 1890-1893 to their shorter-lived siblings. Family histories of centenarians were reconstructed and exceptional longevity validated using early U.S. censuses, Social Security Administration Death Master File, state death indexes, online genealogies and other supplementary data resources. Siblings born to young mothers (<25 years) had significantly higher chances to live to 100 compared to siblings born to older mothers (odds ratio = 2.03, 95% CI = 1.33 - 3.11, P = 0.001) while paternal age and birth order were not associated with exceptional longevity. The second study explores whether people living to 100 and beyond are any different in physical characteristics at young age from their shorter-lived peers. A random representative sample of 240 men born in 1887 and survived to age 100 was selected from the US Social Security Administration database and linked to the US WWI civil draft registration cards collected in 1917 when these men were 30 years old. These validated centenarians were then compared to randomly selected controls matched by calendar year of birth, race and place of draft registration in 1917. It was found that ‘stout’ body build (being in the heaviest 15% of population) was negatively associated with survival to age 100 years. Farmer occupation and large number of children (4+) at age 30 increased the chances of exceptional longevity. Detailed description of dataset development, data cleaning procedure and validation of exceptional longevity is provided for both studies. These results demonstrate that matched case-control design is a useful approach in exploring effects of early-life conditions and middle-life characteristics on exceptional longevity. PMID:22582891

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

PubMed

Kelley, Jay; Schwartz, Gary T

2010-01-19

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

Dental development and life history in living African and Asian apes

PubMed Central

Kelley, Jay; Schwartz, Gary T.

2009-01-01

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

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

PubMed

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

2017-04-01

The Tsimane Health and Life History Project, an integrated bio-behavioral study of the human life course, is designed to test competing hypotheses of human life-history evolution. One aim is to understand the bidirectional connections between life history and social behavior in a high-fertility, kin-based context lacking amenities of modern urban life (e.g. sanitation, banks, electricity). Another aim is to understand how a high pathogen burden influences health and well-being during development and adulthood. A third aim addresses how modernization shapes human life histories and sociality. Here we outline the project's goals, history, and main findings since its inception in 2002. We reflect on the implications of current findings and highlight the need for more coordinated ethnographic and biomedical study of contemporary nonindustrial populations to address broad questions that can situate evolutionary anthropology in a key position within the social and life sciences. © 2017 The Authors Evolutionary Anthropology: Issues, News, and Reviews Published by Wiley Periodicals, Inc.

Early History of Chronic Obstructive Pulmonary Disease 1808-1980.

PubMed

Watson, R Ann; Pride, Neil B

2016-01-01

COPD has become a more popular research area in the last 3 decades, yet the first clear descriptions of acute and chronic bronchitis were in 1808. This brief history, comprehensively referenced, leads us through the early developments in respiratory physiology and their applications. It emphasises the early history of chronic bronchitis and emphysema in the 19(th) and early 20(th) centuries, long before the dominant effects of cigarette smoking emerged. This remains relevant to developing countries today.

Integrating the pace-of-life syndrome across species, sexes and individuals: covariation of life history and personality under pesticide exposure.

PubMed

Debecker, Sara; Sanmartín-Villar, Iago; de Guinea-Luengo, Miguel; Cordero-Rivera, Adolfo; Stoks, Robby

2016-05-01

The pace-of-life syndrome (POLS) hypothesis integrates covariation of life-history traits along a fast-slow continuum and covariation of behavioural traits along a proactive-reactive personality continuum. Few studies have investigated these predicted life-history/personality associations among species and between sexes. Furthermore, whether and how contaminants interfere with POLS patterns remains unexplored. We tested for covariation patterns in life history and in behaviour, and for life-history/personality covariation among species, among individuals within species and between sexes. Moreover, we investigated whether pesticide exposure affects covariation between life history and behaviour and whether species and sexes with a faster POLS strategy have a higher sensitivity to pesticides. We reared larvae of four species of Ischnura damselflies in a common garden experiment with an insecticide treatment (chlorpyrifos absent/present) in the final instar. We measured four life-history traits (larval growth rate during the pesticide treatment, larval development time, adult mass and life span) and two behavioural traits (larval feeding activity and boldness, each before and after the pesticide treatment). At the individual level, life-history traits and behavioural traits aligned along a fast-slow and a proactive-reactive continuum, respectively. Species-specific differences in life history, with fast-lived species having a faster larval growth and development, a lower mass at emergence and a shorter life span, suggested that time constraints in the larval stage were predictably driving life-history evolution both in the larval stage and across metamorphosis in the adult stage. Across species, females were consistently more slow-lived than males, reflecting that a large body size and a long life span are generally more important for females. In contrast to the POLS hypothesis, there was only little evidence for the expected positive coupling between life-history

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…

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

PubMed Central

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

2017-01-01

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

Using Behavior Sequence Analysis to Map Serial Killers' Life Histories.

PubMed

Keatley, David A; Golightly, Hayley; Shephard, Rebecca; Yaksic, Enzo; Reid, Sasha

2018-03-01

The aim of the current research was to provide a novel method for mapping the developmental sequences of serial killers' life histories. An in-depth biographical account of serial killers' lives, from birth through to conviction, was gained and analyzed using Behavior Sequence Analysis. The analyses highlight similarities in behavioral events across the serial killers' lives, indicating not only which risk factors occur, but the temporal order of these factors. Results focused on early childhood environment, indicating the role of parental abuse; behaviors and events surrounding criminal histories of serial killers, showing that many had previous convictions and were known to police for other crimes; behaviors surrounding their murders, highlighting differences in victim choice and modus operandi; and, finally, trial pleas and convictions. The present research, therefore, provides a novel approach to synthesizing large volumes of data on criminals and presenting results in accessible, understandable outcomes.

Life History Insights into the Early Childhood and Education Experiences of Froebel Trainee Teachers 1952-1967

ERIC Educational Resources Information Center

Hoskins, Kate; Smedley, Sue

2016-01-01

Drawing on life-history interview data collected as part of a research project funded by the Froebel Trust, this paper explores the family backgrounds and educational experiences reported by nine women who attended Froebel College located in London in the United Kingdom (UK), in the 1950s and 1960s. Informed by Bourdieu's theories of habitus and…

Nutritional physiology of life-history trade-offs: how food protein-carbohydrate content influences life-history traits in the wing-polymorphic cricket Gryllus firmus.

PubMed

Clark, Rebecca M; Zera, Anthony J; Behmer, Spencer T

2015-01-15

Although life-history trade-offs result from the differential acquisition and allocation of nutritional resources to competing physiological functions, many aspects of this topic remain poorly understood. Wing-polymorphic insects, which possess alternative morphs that trade off allocation to flight capability versus early reproduction, provide a good model system for exploring this topic. In this study, we used the wing-polymorphic cricket Gryllus firmus to test how expression of the flight capability versus reproduction trade-off was modified across a heterogeneous protein-carbohydrate nutritional landscape. Newly molted adult female long- and short-winged crickets were given one of 13 diets with different concentrations and ratios of protein and digestible carbohydrate; for each cricket, we measured consumption patterns, growth and allocation to reproduction (ovary mass) versus flight muscle maintenance (flight muscle mass and somatic lipid stores). Feeding responses in both morphs were influenced more by total macronutrient concentration than by protein-carbohydrate ratio, except at high-macronutrient concentration, where protein-carbohydrate balance was important. Mass gain tended to be greatest on protein-biased diets for both morphs, but was consistently lower across all diets for long-winged females. When long-winged females were fed high-carbohydrate foods, they accumulated greater somatic lipid stores; on high-protein foods, they accumulated greater somatic protein stores. Food protein-carbohydrate content also affected short-winged females (selected for early reproductive onset), which showed dramatic increases in ovary size, including ovarian stores of lipid and protein, on protein-biased foods. This is the first study to show how the concentration and ratio of dietary protein and carbohydrate affects consumption and allocation to key physiological features associated with the reproduction-dispersal life-history trade-off. © 2015. Published by The

Stress exposure in early post-natal life reduces telomere length: an experimental demonstration in a long-lived seabird

PubMed Central

Herborn, Katherine A.; Heidinger, Britt J.; Boner, Winnie; Noguera, Jose C.; Adam, Aileen; Daunt, Francis; Monaghan, Pat

2014-01-01

Exposure to stressors early in life is associated with faster ageing and reduced longevity. One important mechanism that could underlie these late life effects is increased telomere loss. Telomere length in early post-natal life is an important predictor of subsequent lifespan, but the factors underpinning its variability are poorly understood. Recent human studies have linked stress exposure to increased telomere loss. These studies have of necessity been non-experimental and are consequently subjected to several confounding factors; also, being based on leucocyte populations, where cell composition is variable and some telomere restoration can occur, the extent to which these effects extend beyond the immune system has been questioned. In this study, we experimentally manipulated stress exposure early in post-natal life in nestling European shags (Phalacrocorax aristotelis) in the wild and examined the effect on telomere length in erythrocytes. Our results show that greater stress exposure during early post-natal life increases telomere loss at this life-history stage, and that such an effect is not confined to immune cells. The delayed effects of increased telomere attrition in early life could therefore give rise to a ‘time bomb’ that reduces longevity in the absence of any obvious phenotypic consequences early in life. PMID:24648221

Early-life origins of life-cycle well-being: research and policy implications.

PubMed

Currie, Janet; Rossin-Slater, Maya

2015-01-01

Mounting evidence across different disciplines suggests that early-life conditions can have consequences on individual outcomes throughout the life cycle. Relative to other developed countries, the United States fares poorly on standard indicators of early-life health, and this disadvantage may have profound consequences not only for population well-being, but also for economic growth and competitiveness in a global economy. In this paper, we first discuss the research on the strength of the link between early-life health and adult outcomes, and then provide an evidence-based review of the effectiveness of existing U.S. policies targeting the early-life environment. We conclude that there is a robust and economically meaningful relationship between early-life conditions and well-being throughout the life cycle, as measured by adult health, educational attainment, labor market attachment, and other indicators of socioeconomic status. However, there is some variation in the degree to which current policies in the United States are effective in improving early-life conditions. Among existing programs, some of the most effective are the Special Supplemental Program for Women, Infants, and Children (WIC), home visiting with nurse practitioners, and high-quality, center-based early-childhood care and education. In contrast, the evidence on other policies such as prenatal care and family leave is more mixed and limited.

Early life stress and trauma and enhanced limbic activation to emotionally valenced faces in depressed and healthy children.

PubMed

Suzuki, Hideo; Luby, Joan L; Botteron, Kelly N; Dietrich, Rachel; McAvoy, Mark P; Barch, Deanna M

2014-07-01

Previous studies have examined the relationships between structural brain characteristics and early life stress in adults. However, there is limited evidence for functional brain variation associated with early life stress in children. We hypothesized that early life stress and trauma would be associated with increased functional brain activation response to negative emotional faces in children with and without a history of depression. Psychiatric diagnosis and life events in children (starting at age 3-5 years) were assessed in a longitudinal study. A follow-up magnetic resonance imaging (MRI) study acquired data (N = 115 at ages 7-12, 51% girls) on functional brain response to fearful, sad, and happy faces relative to neutral faces. We used a region-of-interest mask within cortico-limbic areas and conducted regression analyses and repeated-measures analysis of covariance. Greater activation responses to fearful, sad, and happy faces in the amygdala and its neighboring regions were found in children with greater life stress. Moreover, an association between life stress and left hippocampal and globus pallidus activity depended on children's diagnostic status. Finally, all children with greater life trauma showed greater bilateral amygdala and cingulate activity specific to sad faces but not the other emotional faces, although right amygdala activity was moderated by psychiatric status. These findings suggest that limbic hyperactivity may be a biomarker of early life stress and trauma in children and may have implications in the risk trajectory for depression and other stress-related disorders. However, this pattern varied based on emotion type and history of psychopathology. Copyright © 2014 American Academy of Child and Adolescent Psychiatry. Published by Elsevier Inc. All rights reserved.

Selection of trilateral continuums of life history strategies under food web interactions.

PubMed

Fujiwara, Masami

2018-03-14

The study of life history strategies has a long history in ecology and evolution, but determining the underlying mechanisms driving the evolution of life history variation and its consequences for population regulation remains a major challenge. In this study, a food web model with constant environmental conditions was used to demonstrate how multi-species consumer-resource interactions (food-web interactions) can create variation in the duration of the adult stage, age of maturation, and fecundity among species. The model included three key ecological processes: size-dependent species interactions, energetics, and transition among developmental stages. Resultant patterns of life history variation were consistent with previous empirical observations of the life history strategies of aquatic organisms referred to as periodic, equilibrium, and opportunistic strategies (trilateral continuums of life history strategies). Results from the simulation model suggest that these three life history strategies can emerge from food web interactions even when abiotic environmental conditions are held constant.

Captive propagation, reproductive biology, and early life history of Etheostoma wapiti (Boulder Darter), E. vulneratum (Wounded Darter), and E. maculatum (Spotted Darter)

USGS Publications Warehouse

Ruble, Crystal L.; Rakes, Patrick L.; Shute, John R.; Welsh, Stuart A.

2016-01-01

Reproductive biology and early life-history data are important for understanding the ecology of fishes. In 2008, we conducted captive propagation studies on 3 species of darters of the subgenus Nothonotus: Etheostoma wapiti (Boulder Darter), E. vulneratum (Wounded Darter), and E. maculatum (Spotted Darter). The length of spawning period and associated range of water temperatures for the Wounded Darter exceeded that of the Spotted Darter and Boulder Darter. The mean number of eggs produced per female was lowest for Boulder Darter and highest in the Wounded Darter. The Boulder Darter had the highest percent of eggs hatched, the lowest percent larval to juvenile stage survivorship, and the lowest mean number of juveniles produced per female. Egg diameters at deposition and prior to hatch were smallest for the Spotted Darter. If reproductive biology and early lifehistory information from captive fishes represent that of wild populations, then the data obtained during this study are relevant to development and implementation of conservation and management plans for these closely related darter species.

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

PubMed

Aktipis, Athena

2016-01-01

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

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.

Life histories predict coral community disassembly under multiple stressors.

PubMed

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

2013-06-01

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

Life history variation among four lake trout morphs at Isle Royale, Lake Superior

USGS Publications Warehouse

Hansen, Michael J.; Nate, Nancy A.; Muir, Andrew M.; Bronte, Charles R.; Zimmerman, Mara S.; Krueger, Charles C.

2016-01-01

Life history traits were compared among four morphs of lake trout at Isle Royale, Lake Superior. Of 738 lake trout caught at Isle Royale, 701 were assigned to a morph (119 humpers, 160 leans, 85 redfins, and 337 siscowets) using a combination of statistical analysis of head and body shape and visual assignment. On average, redfins were longer (544 mm), heavier (1,481 g), heavier at length (Wr = 94), more buoyant, and older (22 years) than siscowets (519 mm; 1,221 g; 90; 19 years), leans (479 mm; 854 g; 82; 13 years), and humpers (443 mm; 697 g; 87; 17 years). On average, leans grew from a younger age at length = 0 and shorter length at age = 0, at a faster early growth rate to a longer asymptotic length than the other three morphs, while redfins grew at a slower instantaneous rate and humpers grew to a shorter asymptotic length than other morphs. On average, leans were longer (562 mm) and older (15 years) at 50% maturity than redfins (427 mm, 12 years), siscowets (401 mm, 11 years), or humpers (394 mm, 13 years). Life history parameters did not differ between males and females within each morph. We conclude that differences in life history attributes of lean, humper, redfin, and siscowet morphs of lake trout are consistent with differential habitat use in waters around Isle Royale, Lake Superior.

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…

The effects of parasites on the early life stages of a damselfish

NASA Astrophysics Data System (ADS)

Sun, D.; Blomberg, S. P.; Cribb, T. H.; McCormick, M. I.; Grutter, A. S.

2012-12-01

Early life history traits, such as larval growth, influence the success of coral reef fish in the transition from the larval to the juvenile life phase. Few studies, however, have examined the relationship between parasites and growth in the early life history stages of such fishes. This study examined how parasite prevalence (% infected) and load, and the relationship between parasite presence and fish growth, differed among life stages of the damselfish Pomacentrus amboinensis. Parasite prevalence decreased significantly between the larval stage, which was sampled immediately before settlement on the reef (97 %) and recently settled juveniles (60 %); prevalence was also high for 4-month-old juveniles (90 %), 7-month-old juveniles (100 %) and adult fish (100 %). Total numbers of parasites per fish decreased dramatically (fourfold) between larval and recently settled fish, and then increased in the older stages to levels similar to those observed in larvae, but they did so more gradually than did prevalence. One explanation for these patterns is that heavily infected larvae were preferentially removed from the population during or soon after settlement. Daily fish growth, determined from otolith increments, revealed that growth did not differ between parasitised and non-parasitised larval fish, whereas recently settled fish that were parasitised had faster growth; these parasitised recently settled fish also displayed faster growth prior to settlement. These data provide evidence that parasites may explain some of the variation in growth and survival observed among coral reef fishes after settlement and thereby have a greater impact on population dynamics than previously understood.

Life history traits and phenotypic selection among sunflower crop–wild hybrids and their wild counterpart: implications for crop allele introgression

PubMed Central

Kost, Matthew A; Alexander, Helen M; Jason Emry, D; Mercer, Kristin L

2015-01-01

Hybridization produces strong evolutionary forces. In hybrid zones, selection can differentially occur on traits and selection intensities may differ among hybrid generations. Understanding these dynamics in crop–wild hybrid zones can clarify crop-like traits likely to introgress into wild populations and the particular hybrid generations through which introgression proceeds. In a field experiment with four crop–wild hybrid Helianthus annuus (sunflower) cross types, we measured growth and life history traits and performed phenotypic selection analysis on early season traits to ascertain the likelihood, and routes, of crop allele introgression into wild sunflower populations. All cross types overwintered, emerged in the spring, and survived until flowering, indicating no early life history barriers to crop allele introgression. While selection indirectly favored earlier seedling emergence and taller early season seedlings, direct selection only favored greater early season leaf length. Further, there was cross type variation in the intensity of selection operating on leaf length. Thus, introgression of multiple early season crop-like traits, due to direct selection for greater early season leaf length, should not be impeded by any cross type and may proceed at different rates among generations. In sum, alleles underlying early season sunflower crop-like traits are likely to introgress into wild sunflower populations. PMID:26029263

Life history traits and phenotypic selection among sunflower crop-wild hybrids and their wild counterpart: implications for crop allele introgression.

PubMed

Kost, Matthew A; Alexander, Helen M; Jason Emry, D; Mercer, Kristin L

2015-06-01

Hybridization produces strong evolutionary forces. In hybrid zones, selection can differentially occur on traits and selection intensities may differ among hybrid generations. Understanding these dynamics in crop-wild hybrid zones can clarify crop-like traits likely to introgress into wild populations and the particular hybrid generations through which introgression proceeds. In a field experiment with four crop-wild hybrid Helianthus annuus (sunflower) cross types, we measured growth and life history traits and performed phenotypic selection analysis on early season traits to ascertain the likelihood, and routes, of crop allele introgression into wild sunflower populations. All cross types overwintered, emerged in the spring, and survived until flowering, indicating no early life history barriers to crop allele introgression. While selection indirectly favored earlier seedling emergence and taller early season seedlings, direct selection only favored greater early season leaf length. Further, there was cross type variation in the intensity of selection operating on leaf length. Thus, introgression of multiple early season crop-like traits, due to direct selection for greater early season leaf length, should not be impeded by any cross type and may proceed at different rates among generations. In sum, alleles underlying early season sunflower crop-like traits are likely to introgress into wild sunflower populations.

Early Childhood Education: History, Theory, and Practice

ERIC Educational Resources Information Center

Morgan, Harry

2006-01-01

In this book, the author covers the history, theory, and practices that influence early childhood education along with an emphasis on infant and toddler care and education. He also presents a comparison of the conflict between education planners who support early childhood studies and state school systems whose cost-saving measures are dismantling…

Ecological and life-history factors influencing the evolution of maternal antibody allocation: a phylogenetic comparison

PubMed Central

Addison, BriAnne; Klasing, Kirk C.; Robinson, W. Douglas; Austin, Suzanne H.; Ricklefs, Robert E.

2009-01-01

Maternally derived yolk antibodies provide neonates with immune protection in early life at negligible cost to mothers. However, developmental effects on the neonate's future immunity are potentially costly and thus could limit yolk antibody deposition. The benefits to neonatal immunity must be balanced against costs, which may depend on neonate vulnerability to pathogens, developmental trajectories and the immunological strategies best suited to a species' pace of life. We measured yolk antibodies and life-history features of 23 species of small Neotropical birds and assessed the evidence for each of several hypotheses for life history and ecological effects on the evolution of yolk antibody levels. Developmental period and yolk antibodies are negatively related, which possibly reflect the importance of humoral immune priming through antigen exposure, and selection to avoid autoimmunity, in species with a slower pace of life. There is also a strong relationship between body size and yolk antibody concentration, suggesting that larger species are architecturally equipped to produce and transfer higher concentrations of antibodies. These results suggest that developmental effects of maternally derived antibodies, such as imprinting effects on B-cell diversity or autoimmune effects, are important and deserve more consideration in future research. PMID:19710063

Life-history evolution in ants: the case of Cardiocondyla

PubMed Central

2017-01-01

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

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

PubMed Central

Figueredo, Aurelio José; Ellis, Bruce J.

2010-01-01

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

Alchemy--A History of Early Technology.

ERIC Educational Resources Information Center

Pollard, A. M.

1988-01-01

Reviews the history of alchemy including personalities and methods. Discusses the philosophy associated with various early chemists and alchemists. Attempts to show that it was not unreasonable for ancient alchemists to believe in the possibility of transmutation. (CW)

Early-life disruption of amphibian microbiota decreases later-life resistance to parasites.

PubMed

Knutie, Sarah A; Wilkinson, Christina L; Kohl, Kevin D; Rohr, Jason R

2017-07-20

Changes in the early-life microbiota of hosts might affect infectious disease risk throughout life, if such disruptions during formative times alter immune system development. Here, we test whether an early-life disruption of host-associated microbiota affects later-life resistance to infections by manipulating the microbiota of tadpoles and challenging them with parasitic gut worms as adults. We find that tadpole bacterial diversity is negatively correlated with parasite establishment in adult frogs: adult frogs that had reduced bacterial diversity as tadpoles have three times more worms than adults without their microbiota manipulated as tadpoles. In contrast, adult bacterial diversity during parasite exposure is not correlated with parasite establishment in adult frogs. Thus, in this experimental setup, an early-life disruption of the microbiota has lasting reductions on host resistance to infections, which is possibly mediated by its effects on immune system development. Our results support the idea that preventing early-life disruption of host-associated microbiota might confer protection against diseases later in life.Early-life microbiota alterations can affect infection susceptibility later in life, in animal models. Here, Knutie et al. show that manipulating the microbiota of tadpoles leads to increased susceptibility to parasitic infection in adult frogs, in the absence of substantial changes in the adults' microbiota.

Exogenous determinants of early-life conditions, and mortality later in life.

PubMed

van den Berg, Gerard J; Doblhammer, Gabriele; Christensen, Kaare

2009-05-01

We analyze causal effects of conditions early in life on the individual mortality rate later in life. Conditions early in life are captured by transitory features of the macro-environment around birth, notably the state of the business cycle around birth, but also food price deviations, weather indicators, and demographic indicators. We argue that these features can only affect high-age mortality by way of the individual early-life conditions. Moreover, they are exogenous from the individual point of view, which is a methodological advantage compared to the use of unique characteristics of the newborn individual or his or her family or household as early-life indicators. We collected national annual time-series data on the above-mentioned indicators, and we combine these to the individual data records from the Danish Twin Registry covering births in 1873-1906. The empirical analyses (mostly based on the estimation of duration models) indicate a significant negative causal effect of economic conditions early in life on individual mortality rates at higher ages. If the national economic performance in the year of birth exceeds its trend value (i.e., if the business cycle is favorable) then the mortality rate later in life is lower. The implied effect on the median lifetime of those who survive until age 35 is about 10 months. A systematic empirical exploration of all macro-indicators reveals that economic conditions in the first years after birth also affect mortality rates later in life.

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

USGS Publications Warehouse

Ackerman, Joshua T.; Eadie, J.M.; Moore, T.G.

2006-01-01

Life-history theory predicts that longer-lived, less fecund species should take fewer risks when exposed to predation than shorter-lived, more fecund species. We tested this prediction for seven species of dabbling ducks (Anas) by measuring the approach behavior (behavior of ducks when approaching potential landing sites) of 1099 duck flocks during 37 hunting trials and 491 flocks during 13 trials conducted immediately after the 1999-2000 waterfowl hunting season in California, USA. We also experimentally manipulated the attractiveness of the study site by using two decoy treatments: (1) traditional, stationary decoys only, and (2) traditional decoys in conjunction with a mechanical spinning-wing decoy. Approach behavior of ducks was strongly correlated with their life history. Minimum approach distance was negatively correlated with reproductive output during each decoy treatment and trial type. Similarly, the proportion of flocks taking risk (approaching landing sites to within 45 m) was positively correlated with reproductive output. We found similar patterns of approach behavior in relation to other life-history parameters (i.e., adult female body mass and annual adult female survival rate). Thus, species characterized by a slower life-history strategy (e.g., Northern Pintail [A. acuta]) were more risk-averse than species with a faster life-history strategy (e.g., Cinnamon Teal [A. cyanoptera]). Furthermore, although we were able to reduce risk-averseness using the spinning-wing decoy, we were unable to override the influence of life history on risk-taking behavior. Alternative explanations did not account for the observed correlation between approach behavior and life-history parameters. These results suggest that life history influences the risk-taking behavior of dabbling ducks and provide an explanation for the differential vulnerability of waterfowl to harvest. ?? The Cooper Ornithological Society 2006.

LABORATORY EVOLUTION OF LIFE-HISTORY TRAITS IN THE BEAN WEEVIL (ACANTHOSCELIDES OBTECTUS): THE EFFECTS OF DENSITY-DEPENDENT AND AGE-SPECIFIC SELECTION.

PubMed

Tucić, Nikola; Stojković, Oliver; Gliksman, Ivana; Milanović, Agana; Šešlija, Darka

1997-12-01

Four types of laboratory populations of the bean weevil (Acanthoscelides obtectus) have been developed to study the effects of density-dependent and age-specific selection. These populations have been selected at high (K) and low larval densities (r) as well as for reproduction early (Y) and late (O) in life. The results presented here suggest that the r- and K-populations (density-dependent selection regimes) have differentiated from each other with respect to the following life-history traits: egg-to-adult viability at high larval density (K > r), preadult developmental time (r > K), body weight (r > K), late fecundity (K > r), total realized fecundity (r > K), and longevity of males (r > K). It was also found that the following traits responded in statistically significant manner in populations subjected to different age-specific selection regimes: egg-to-adult viability (O > Y), body weight (O > Y), early fecundity (Y > O), late fecundity (O > Y), and longevity of females and males (O > Y). Although several life-history traits (viability, body weight, late fecundity) responded in similar manner to both density-dependent and age-specific selection regimes, it appears that underlying genetic and physiological mechanisms responsible for differentiation of the r/K and Y/O populations are different. We have also tested quantitative genetic basis of the bean weevil life-history traits in the populations experiencing density-dependent and age-specific selection. Among the traits traded-off within age-specific selection regimes, only early fecundity showed directional dominance, whereas late fecundity and longevity data indicated additive inheritance. In contrast to age-specific selecton regimes, three life-history traits (developmental time, body size, total fecundity) in the density-sependent regimes exhibited significant dominance effects. Lastly, we have tested the congruence between short-term and long-term effects of larval densities. The comparisons of the

Reproductive strategy, spawning induction, spawning temperatures and early life history of captive sicklefin chub Macrhybopsis meeki

USGS Publications Warehouse

Albers, Janice; Wildhaber, Mark L.

2017-01-01

Macrhybopsis reproduction and propagule traits were studied in the laboratory using two temperature regimes and three hormone treatments to determine which methods produced the most spawns. Only sicklefin chub Macrhybopsis meeki spawned successfully although sturgeon chub Macrhybopsis gelida released unfertilized eggs. All temperature and hormone treatments produced M. meeki spawns, but two treatments had similar success rates at 44 and 43%, consisting of a constant daily temperature with no hormone added, or daily temperature fluctuations with hormone added to the water. Spawns consisted of multiple successful demersal circular swimming spawning embraces interspersed with circular swims without embraces. The most spawns observed for one female was four and on average, 327 eggs were collected after each spawn. The water-hardened eggs were semi-buoyant and non-adhesive, the first confirmation of this type of reproductive guild in the Missouri River Macrhybopsis sp. From spawn, larvae swam vertically until 123 accumulated degree days (° D) and 167° D for consumption of first food. Using average water speed and laboratory development time, the predicted drift distance for eggs and larvae could be 468–592 km in the lower Missouri River. Results from this study determined the reproductive biology and early life history of Macrhybopsis spp. and provided insight into their population dynamics in the Missouri River.

Early Life Stages

EPA Pesticide Factsheets

Childhood should be viewed as a sequence of lifestages, from birth through infancy and adolescence. When assessing early life risks, consideration is given to risks resulting from fetal exposure via the pregnant mother, as well as postnatal exposures.

Late-life and life history predictors of older adults' high-risk alcohol consumption and drinking problems.

PubMed

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

2010-04-01

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 75-85. 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 and 20 years later. 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. 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- 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. 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. Published by Elsevier Ireland Ltd.

The life-history basis of behavioural innovations

PubMed Central

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

2016-01-01

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

Experimental reintroduction reveals novel life-history variation in Laysan Ducks (Anas laysanensis)

USGS Publications Warehouse

Walters, Jeffrey R.; Reynolds, Michelle H.

2013-01-01

Subfossil remains indicate that the Laysan Duck (Anas laysanensis) formerly occurred throughout the Hawaiian archipelago, but for more than 150 years it has been confined to a single, small atoll in the northwestern chain, Laysan Island. In 2004–2005, 42 ducks were reintroduced from Laysan to Midway Atoll, where they exhibited variation in life history never observed on Laysan. On Laysan, females have never been observed to breed successfully at age 1 year and few attempt it, whereas on Midway, females routinely raised young at <1 year of age. Mean (± SD) clutch size on Midway (7.0 ± 1.1, n = 41) was larger than the maximum clutch size of six eggs observed on Laysan. On Midway, renesting following nest failure (0.55 probability, n = 27) and double brooding (0.50, n = 54) were routine, and two instances of triple brooding were observed, whereas on Laysan, renesting and double brooding are rare (0.05 probability for both during our study; n = 21 and 19, respectively) and triple brooding has never been observed. Other novel life history on Midway included early cessation of parental care to renest. Altered life history on Midway is likely related to better feeding conditions and low population density compared with Laysan. An especially intriguing possibility is that the phenotypic plasticity observed represents exposure of hidden reaction norms evolved when the species inhabited a range of environments, but several alternative explanations exist. Future reintroductions of this species may provide opportunities to test hypotheses about mechanisms underlying phenotypic plasticity.

Life history theory predicts fish assemblage response to hydrologic regimes.

PubMed

Mims, Meryl C; Olden, Julian D

2012-01-01

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

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

ERIC Educational Resources Information Center

Cazers, Gunars; Curtner-Smith, Matthew D.

2017-01-01

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

Extraordinarily rapid life-history divergence between Cryptasterina sea star species.

PubMed

Puritz, Jonathan B; Keever, Carson C; Addison, Jason A; Byrne, Maria; Hart, Michael W; Grosberg, Richard K; Toonen, Robert J

2012-10-07

Life history plays a critical role in governing microevolutionary processes such as gene flow and adaptation, as well as macroevolutionary processes such speciation. Here, we use multilocus phylogeographic analyses to examine a speciation event involving spectacular life-history differences between sister species of sea stars. Cryptasterina hystera has evolved a suite of derived life-history traits (including internal self-fertilization and brood protection) that differ from its sister species Cryptasterina pentagona, a gonochoric broadcast spawner. We show that these species have only been reproductively isolated for approximately 6000 years (95% highest posterior density of 905-22 628), and that this life-history change may be responsible for dramatic genetic consequences, including low nucleotide diversity, zero heterozygosity and no gene flow. The rapid divergence of these species rules out some mechanisms of isolation such as adaptation to microhabitats in sympatry, or slow divergence by genetic drift during prolonged isolation. We hypothesize that the large phenotypic differences between species relative to the short divergence time suggests that the life-history differences observed may be direct responses to disruptive selection between populations. We speculate that local environmental or demographic differences at the southern range margin are possible mechanisms of selection driving one of the fastest known marine speciation events.

Habitability and the Possibility of Extraterrestrial Life in the Early Telescope Era

NASA Astrophysics Data System (ADS)

Reynolds, Sarah

2014-01-01

Early telescopic observations of the Moon and planets prompted great interest in the already-existing debate about the possibility of life on the Moon and other worlds. New observations of the lunar surface, revealing an apparently Earth-like terrain and possibly the presence of bodies of water, were often considered in relation to their implications for the existence of lunar inhabitants. This depended upon establishing what constituted the fundamental requirements for life and the boundaries of habitability. The growing support for the heliocentric Copernican astronomy was also changing perceptions of the relationships between the Earth, the Moon, and the planets. Works such as Johannes Kepler’s Somnium and John Wilkins’ The Discovery of a World in the Moone presented views of extraterrestrial life that were shifting from the supernatural to the natural, in correspondence with the celestial bodies’ new positions in the cosmos. This paper considers how these and other works from the early telescope era reveal changes in the nature of astronomical speculation about extraterrestrial life and the conditions construed as “habitability,” and what significance that history has for us today in the new era of extrasolar planet discovery.

Rapid weight gain after birth predicts life history and reproductive strategy in Filipino males

PubMed Central

Kuzawa, Christopher W.; McDade, Thomas W.; Adair, Linda S.; Lee, Nanette

2010-01-01

Ecological cues during prenatal and postnatal development may allow organisms to adjust reproductive strategy. The hypothalamic-pituitary-gonadal (HPG) axis is a prime candidate for adaptive plasticity as a result of its critical period of birth to 6 mo (B6M) in humans and the role of testosterone in the development and maintenance of costly sexually dimorphic somatic and behavioral traits. We hypothesized that weight velocity specific to B6M would predict male life history characteristics, including maturational timing, reproductive hormones, adult size, strength, and sexual activity. Data come from 770 Filipino men (age 20.5–22.5 y) followed since birth, with predictor variables including birth weight and weight velocities calculated at 6-mo intervals during the first 2 y of life. As expected, infants who were breastfed experienced less diarrhea, lived in wealthier households with better hygiene, and grew faster from B6M. Males with rapid B6M growth reached puberty earlier and, as young adults, had higher testosterone levels, were taller, more muscular, and had higher grip strength. They also had sex earlier and were more likely to report having had sex in the past month, resulting in more lifetime sex partners. Relationships between B6M weight gain and physical outcomes were generally not present or weaker in female subjects. We conclude that rapid weight gain specific to the brief postnatal hypothalamic-pituitary-gonadal critical period predicts early maturation and sexual activity, elevated hormone production, and more costly adult somatic characteristics among the male subjects in this sample. These findings provide evidence for early life developmental plasticity in male life history and reproductive strategy in humans. PMID:20837542

African ancestry, early life exposures, and respiratory morbidity in early childhood.

PubMed

Kumar, R; Tsai, H-J; Hong, X; Gignoux, C; Pearson, C; Ortiz, K; Fu, M; Pongracic, J A; Burchard, E G; Bauchner, H; Wang, X

2012-02-01

Racial disparities persist in early childhood wheezing and cannot be completely explained by known risk factors. To evaluate the associations of genetic ancestry and self-identified race with early childhood recurrent wheezing, accounting for socio-economic status (SES) and early life exposures. We studied 1034 children in an urban, multi-racial, prospective birth cohort. Multivariate logistic regression was used to evaluate the association of genetic ancestry as opposed to self-identified race with recurrent wheezing (>3 episodes). Sequential models accounted for demographic, socio-economic factors and early life risk factors. Genetic ancestry, estimated using 150 ancestry informative markers, was expressed in deciles. Approximately 6.1% of subjects (mean age 3.1 years) experienced recurrent wheezing. After accounting for SES and demographic factors, African ancestry (OR: 1.16, 95% CI: 1.02-1.31) was significantly associated with recurrent wheezing. By self-reported race, hispanic subjects had a borderline decrease in risk of wheeze compared with African Americans (OR: 0.44, 95% CI: 0.19-1.00), whereas white subjects (OR: 0.46, 95% CI: 0.14-1.57) did not have. After further adjustment for known confounders and early life exposures, both African (OR: 1.19, 95% CI: 1.05-1.34) and European ancestry (OR: 0.84, 95% CI: 0.74-0.94) retained a significant association with recurrent wheezing, as compared with self-identified race (OR(whites) : 0.31, 95% CI: 0.09-1.14; OR(hispanic) : 0.47, 95% CI: 0.20-1.08). There were no significant interactions between ancestry and early life factors on recurrent wheezing. In contrast to self-identified race, African ancestry remained a significant, independent predictor of early childhood wheezing after accounting for early life and other known risk factors associated with lung function changes and asthma. Genetic ancestry may be a powerful way to evaluate wheezing disparities and a proxy for differentially distributed genetic and

African ancestry, early life exposures, and respiratory morbidity in early childhood

PubMed Central

Kumar, R.; Tsai, H.-J.; Hong, X.; Gignoux, C.; Pearson, C.; Ortiz, K.; Fu, M.; Pongracic, J. A.; Burchard, E. G.; Bauchner, H.; Wang, X.

2012-01-01

Summary Background Racial disparities persist in early childhood wheezing and cannot be completely explained by known risk factors. Objective To evaluate the associations of genetic ancestry and self-identified race with early childhood recurrent wheezing, accounting for socio-economic status (SES) and early life exposures. Methods We studied 1034 children in an urban, multi-racial, prospective birth cohort. Multivariate logistic regression was used to evaluate the association of genetic ancestry as opposed to self-identified race with recurrent wheezing (>3 episodes). Sequential models accounted for demographic, socio-economic factors and early life risk factors. Genetic ancestry, estimated using 150 ancestry informative markers, was expressed in deciles. Results Approximately 6.1% of subjects (mean age 3.1 years) experienced recurrent wheezing. After accounting for SES and demographic factors, African ancestry (OR: 1.16, 95% CI: 1.02–1.31) was significantly associated with recurrent wheezing. By self-reported race, hispanic subjects had a borderline decrease in risk of wheeze compared with African Americans (OR: 0.44, 95% CI: 0.19–1.00), whereas white subjects (OR: 0.46, 95% CI: 0.14–1.57) did not have. After further adjustment for known confounders and early life exposures, both African (OR: 1.19, 95% CI: 1.05–1.34) and European ancestry (OR: 0.84, 95% CI: 0.74–0.94) retained a significant association with recurrent wheezing, as compared with self-identified race (ORwhites: 0.31, 95% CI: 0.09–1.14; ORhispanic: 0.47, 95% CI: 0.20–1.08). There were no significant interactions between ancestry and early life factors on recurrent wheezing. Conclusions and Clinical Relevance In contrast to self-identified race, African ancestry remained a significant, independent predictor of early childhood wheezing after accounting for early life and other known risk factors associated with lung function changes and asthma. Genetic ancestry may be a powerful way to

Early-life nutritional effects on the female reproductive system.

PubMed

Chan, K A; Tsoulis, M W; Sloboda, D M

2015-02-01

There is now considerable epidemiological and experimental evidence indicating that early-life environmental conditions, including nutrition, affect subsequent development in later life. These conditions induce highly integrated responses in endocrine-related homeostasis, resulting in persistent changes in the developmental trajectory producing an altered adult phenotype. Early-life events trigger processes that prepare the individual for particular circumstances that are anticipated in the postnatal environment. However, where the intrauterine and postnatal environments differ markedly, such modifications to the developmental trajectory may prove maladaptive in later life. Reproductive maturation and function are similarly influenced by early-life events. This should not be surprising, because the primordial follicle pool is established early in life and is thus vulnerable to early-life events. Results of clinical and experimental studies have indicated that early-life adversity is associated with a decline in ovarian follicular reserve, changes in ovulation rates, and altered age at onset of puberty. However, the underlying mechanisms regulating the relationship between the early-life developmental environment and postnatal reproductive development and function are unclear. This review examines the evidence linking early-life nutrition and effects on the female reproductive system, bringing together clinical observations in humans and experimental data from targeted animal models. © 2015 Society for Endocrinology.

Early-Life Origins of Life-Cycle Well-Being: Research and Policy Implications

ERIC Educational Resources Information Center

Currie, Janet; Rossin-Slater, Maya

2015-01-01

Mounting evidence across different disciplines suggests that early-life conditions can have consequences on individual outcomes throughout the life cycle. Relative to other developed countries, the United States fares poorly on standard indicators of early-life health, and this disadvantage may have profound consequences not only for population…

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…

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…

A Life History Approach to Delineating How Harsh Environments and Hawk Temperament Traits Differentially Shape Children's Problem-Solving Skills

ERIC Educational Resources Information Center

Suor, Jennifer H.; Sturge-Apple, Melissa L.; Davies, Patrick T.; Cicchetti, Dante

2017-01-01

Harsh environments are known to predict deficits in children's cognitive abilities. Life history theory approaches challenge this interpretation, proposing stressed children's cognition becomes specialized to solve problems in fitness-enhancing ways. The goal of this study was to examine associations between early environmental harshness and…

Preventing Obesity Across Generations: Evidence for Early Life Intervention.

PubMed

Haire-Joshu, Debra; Tabak, Rachel

2016-01-01

To prevent the intergenerational transfer of obesity and end the current epidemic, interventions are needed across the early life stages, from preconception to prenatal to infancy through the age of 2 years. The foundation for obesity is laid in early life by actions and interactions passed from parent to child that have long-lasting biologic and behavioral consequences. The purpose of this paper is to examine the best evidence about (a) factors in parents and offspring that promote obesity during the early life stages, (b) the social determinants and dimensions of obesity in early life, (c) promising and effective interventions for preventing obesity in early life, and (d) opportunities for future research into strategies to disrupt the intergenerational cycle of obesity that begins early in life. The pathway for halting the intergenerational obesity epidemic requires the discovery and development of evidence-based interventions that can act across multiple dimensions of influence on early life.

Preventing Obesity Across Generations: Evidence for Early Life Intervention

PubMed Central

Haire-Joshu, Debra; Tabak, Rachel

2017-01-01

To prevent the intergenerational transfer of obesity and end the current epidemic, interventions are needed across the early life stages, from preconception to prenatal to infancy through the age of 2 years. The foundation for obesity is laid in early life by actions and interactions passed from parent to child that have long-lasting biologic and behavioral consequences. The purpose of this paper is to examine the best evidence about (a) factors in parents and offspring that promote obesity during the early life stages, (b) the social determinants and dimensions of obesity in early life, (c) promising and effective interventions for preventing obesity in early life, and (d) opportunities for future research into strategies to disrupt the intergenerational cycle of obesity that begins early in life. The pathway for halting the intergenerational obesity epidemic requires the discovery and development of evidence-based interventions that can act across multiple dimensions of influence on early life. PMID:26989828

Assessing the quality of life history information in publicly available databases.

PubMed

Thorson, James T; Cope, Jason M; Patrick, Wesley S

2014-01-01

Single-species life history parameters are central to ecological research and management, including the fields of macro-ecology, fisheries science, and ecosystem modeling. However, there has been little independent evaluation of the precision and accuracy of the life history values in global and publicly available databases. We therefore develop a novel method based on a Bayesian errors-in-variables model that compares database entries with estimates from local experts, and we illustrate this process by assessing the accuracy and precision of entries in FishBase, one of the largest and oldest life history databases. This model distinguishes biases among seven life history parameters, two types of information available in FishBase (i.e., published values and those estimated from other parameters), and two taxa (i.e., bony and cartilaginous fishes) relative to values from regional experts in the United States, while accounting for additional variance caused by sex- and region-specific life history traits. For published values in FishBase, the model identifies a small positive bias in natural mortality and negative bias in maximum age, perhaps caused by unacknowledged mortality caused by fishing. For life history values calculated by FishBase, the model identified large and inconsistent biases. The model also demonstrates greatest precision for body size parameters, decreased precision for values derived from geographically distant populations, and greatest between-sex differences in age at maturity. We recommend that our bias and precision estimates be used in future errors-in-variables models as a prior on measurement errors. This approach is broadly applicable to global databases of life history traits and, if used, will encourage further development and improvements in these databases.

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, ...

A developmental perspective on early-life exposure to neurotoxicants.

PubMed

Bellinger, David C; Matthews-Bellinger, Julia A; Kordas, Katarzyna

2016-09-01

Studies of early-life neurotoxicant exposure have not been designed, analyzed, or interpreted in the context of a fully developmental perspective. The goal of this paper is to describe the key principles of a developmental perspective and to use examples from the literature to illustrate the relevance of these principles to early-life neurotoxicant exposures. Four principles are discussed: 1) the effects of early-life neurotoxicant exposure depend on a child's developmental context; 2) deficits caused by early-life exposure initiate developmental cascades that can lead to pathologies that differ from those observed initially; 3) early-life neurotoxicant exposure has intra-familial and intergenerational impacts; 4) the impacts of early-life neurotoxicant exposure influence a child's ability to respond to future insults. The first principle is supported by considerable evidence, but the other three have received much less attention. Incorporating a developmental perspective in studies of early-life neurotoxicant exposures requires prospective collection of data on a larger array of covariates than usually considered, using analytical approaches that acknowledge the transactional processes between a child and the environment and the phenomenon of developmental cascades. Consideration of early-life neurotoxicant exposure within a developmental perspective reveals that many issues remain to be explicated if we are to achieve a deep understanding of the societal health burden associated with early-life neurotoxicant exposures. Copyright © 2016 Elsevier Ltd. All rights reserved.

Transgenerational latent early-life associated regulation unites environment and genetics across generations

PubMed Central

Lahiri, Debomoy K; Maloney, Bryan; Bayon, Baindu L; Chopra, Nipun; White, Fletcher A; Greig, Nigel H; Nurnberger, John I

2016-01-01

The origin of idiopathic diseases is still poorly understood. The latent early-life associated regulation (LEARn) model unites environmental exposures and gene expression while providing a mechanistic underpinning for later-occurring disorders. We propose that this process can occur across generations via transgenerational LEARn (tLEARn). In tLEARn, each person is a ‘unit’ accumulating preclinical or subclinical ‘hits’ as in the original LEARn model. These changes can then be epigenomically passed along to offspring. Transgenerational accumulation of ‘hits’ determines a sporadic disease state. Few significant transgenerational hits would accompany conception or gestation of most people, but these may suffice to ‘prime’ someone to respond to later-life hits. Hits need not produce symptoms or microphenotypes to have a transgenerational effect. Testing tLEARn requires longitudinal approaches. A recently proposed longitudinal epigenome/envirome-wide association study would unite genetic sequence, epigenomic markers, environmental exposures, patient personal history taken at multiple time points and family history. PMID:26950428

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…

Dinetah: An Early History of the Navajo People.

ERIC Educational Resources Information Center

Sundberg, Lawrence D.

Originally written for Navajo elementary school students, this book chronicles the history of the Navajo people from prehistory to 1868. The book presents a sympathetic history of a people who depended on their tenacity and creative adaptability to survive troubled times. Chapters examine how Navajo culture changed from that of an early hunting…

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

Retinal vascular imaging in early life: insights into processes and risk of cardiovascular disease

PubMed Central

Li, Ling‐Jun; Ikram, Mohammad Kamran

2015-01-01

Abstract Cardiovascular disease (CVD) is the leading cause of morbidity and mortality globally. In recent years, studies have shown that the origins of CVD may be traced to vascular and metabolic processes in early life. Retinal vascular imaging is a new technology that allows detailed non‐invasive in vivo assessment and monitoring of the microvasculature. In this systematic review, we described the application of retinal vascular imaging in children and adolescents, and we examined the use of retinal vascular imaging in understanding CVD risk in early life. We reviewed all publications with quantitative retinal vascular assessment in two databases: PubMed and Scopus. Early life CVD risk factors were classified into four groups: birth risk factors, environmental risk factors, systemic risk factors and conditions linked to future CVD development. Retinal vascular changes were associated with lower birth weight, shorter gestational age, low‐fibre and high‐sugar diet, lesser physical activity, parental hypertension history, childhood hypertension, childhood overweight/obesity, childhood depression/anxiety and childhood type 1 diabetes mellitus. In summary, there is increasing evidence supporting the view that structural changes in the retinal microvasculature are associated with CVD risk factors in early life. Thus, the retina is a useful site for pre‐clinical assessment of microvascular processes that may underlie the future development of CVD in adulthood. PMID:26435039

Arrests, Recent Life Circumstances, and Recurrent Job Loss for At-Risk Young Men: An Event-History Analysis

ERIC Educational Resources Information Center

Wiesner, Margit; Capaldi, Deborah M.; Kim, Hyoun K.

2010-01-01

This study used longitudinal data from 202 at-risk young men to examine effects of arrests, prior risk factors, and recent life circumstances on job loss across a 7-year period in early adulthood. Repeated failure-time continuous event-history analysis indicated that occurrence of job loss was primarily related to prior mental health problems,…

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

Good daily habits during the early stages of life determine success throughout life.

PubMed

Kohyama, Jun

2016-01-01

This paper assesses hypothesis that sufficient sleep duration and proper circadian rhythms during the early stages of life are indispensable to a successful life. Successful life was defined according to the famous cohort studies of Mischel's and Dunedin. To assess the hypothesis, neuronal elements presumably affecting early daily habits and successful life are reviewed. The effect of sufficient sleep duration and proper circadian rhythms during early stages of life on the development of the prefrontal cortex has been found to be the key issue to verify the hypothesis. Socioeconomic status is found to be another issue to be studied.

Ovipositor morphology correlates with life history evolution in agaonid fig wasps

NASA Astrophysics Data System (ADS)

Elias, Larissa Galante; Kjellberg, Finn; Farache, Fernando Henrique Antoniolli; Almeida, Eduardo A. B.; Rasplus, Jean-Yves; Cruaud, Astrid; Peng, Yan-Qiong; Yang, Da-Rong; Pereira, Rodrigo Augusto Santinelo

2018-07-01

The high adaptive success of parasitic Hymenoptera might be related to the use of different oviposition sites, allowing niche partitioning among co-occurring species resulting in life history specialization and diversification. In this scenario, evolutionary changes in life history and resources for oviposition can be associated with changes in ovipositor structure, allowing exploitation of different substrates for oviposition. We used a formal phylogenetic framework to investigate the evolution of ovipositor morphology and life history in agaonid wasps. We sampled 24 species with different life histories belonging to all main clades of Agaonidae including representatives of all described genera of non-pollinating fig wasps (NPFW). Our results show an overall correlation between ovipositor morphology and life history in agaonid fig wasps. Ovipositor morphologies seem to be related to constraints imposed by features of the oviposition sites since ovipositor morphology has experienced convergent evolution at least four times in Sycophaginae (Agaonidae) according to the resource used. Non-galling species have more distantly spaced teeth with uneven spacing, as opposed to the observed morphology of galling species. Our results suggest that the ancestral condition for ovipositor morphology was most likely the presence of one or two apical teeth. Regarding life history, ovary galling species that oviposit in receptive figs possibly represent the ancestral condition. Different ovipositor characteristics allow exploitation of new niches and may be related to resource partitioning and species co-existence in the fig-fig wasp system.

Material security, life history, and moralistic religions: A cross-cultural examination.

PubMed

Purzycki, Benjamin Grant; Ross, Cody T; Apicella, Coren; Atkinson, Quentin D; Cohen, Emma; McNamara, Rita Anne; Willard, Aiyana K; Xygalatas, Dimitris; Norenzayan, Ara; Henrich, Joseph

2018-01-01

Researchers have recently proposed that "moralistic" religions-those with moral doctrines, moralistic supernatural punishment, and lower emphasis on ritual-emerged as an effect of greater wealth and material security. One interpretation appeals to life history theory, predicting that individuals with "slow life history" strategies will be more attracted to moralistic traditions as a means to judge those with "fast life history" strategies. As we had reservations about the validity of this application of life history theory, we tested these predictions with a data set consisting of 592 individuals from eight diverse societies. Our sample includes individuals from a wide range of traditions, including world religions such as Buddhism, Hinduism and Christianity, but also local traditions rooted in beliefs in animism, ancestor worship, and worship of spirits associated with nature. We first test for the presence of associations between material security, years of formal education, and reproductive success. Consistent with popular life history predictions, we find evidence that material security and education are associated with reduced reproduction. Building on this, we then test whether or not these demographic factors predict the moral concern, punitiveness, attributed knowledge-breadth, and frequency of ritual devotions towards two deities in each society. Here, we find no reliable evidence of a relationship between number of children, material security, or formal education and the individual-level religious beliefs and behaviors. We conclude with a discussion of why life-history theory is an inadequate interpretation for the emergence of factors typifying the moralistic traditions.

Early life trauma, depression and the glucocorticoid receptor gene--an epigenetic perspective.

PubMed

Smart, C; Strathdee, G; Watson, S; Murgatroyd, C; McAllister-Williams, R H

2015-12-01

Hopes to identify genetic susceptibility loci accounting for the heritability seen in unipolar depression have not been fully realized. Family history remains the 'gold standard' for both risk stratification and prognosis in complex phenotypes such as depression. Meanwhile, the physiological mechanisms underlying life-event triggers for depression remain opaque. Epigenetics, comprising heritable changes in gene expression other than alterations of the nucleotide sequence, may offer a way to deepen our understanding of the aetiology and pathophysiology of unipolar depression and optimize treatments. A heuristic target for exploring the relevance of epigenetic changes in unipolar depression is the hypothalamic-pituitary-adrenal (HPA) axis. The glucocorticoid receptor (GR) gene (NR3C1) has been found to be susceptible to epigenetic modification, specifically DNA methylation, in the context of environmental stress such as early life trauma, which is an established risk for depression later in life. In this paper we discuss the progress that has been made by studies that have investigated the relationship between depression, early trauma, the HPA axis and the NR3C1 gene. Difficulties with the design of these studies are also explored. Future efforts will need to comprehensively address epigenetic natural histories at the population, tissue, cell and gene levels. The complex interactions between the epigenome, genome and environment, as well as ongoing nosological difficulties, also pose significant challenges. The work that has been done so far is nevertheless encouraging and suggests potential mechanistic and biomarker roles for differential DNA methylation patterns in NR3C1 as well as novel therapeutic targets.

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

PubMed

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

2008-12-01

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.

A trait-based framework to understand life history of mycorrhizal fungi.

PubMed

Chagnon, Pierre-Luc; Bradley, Robert L; Maherali, Hafiz; Klironomos, John N

2013-09-01

Despite the growing appreciation for the functional diversity of arbuscular mycorrhizal (AM) fungi, our understanding of the causes and consequences of this diversity is still poor. In this opinion article, we review published data on AM fungal functional traits and attempt to identify major axes of life history variation. We propose that a life history classification system based on the grouping of functional traits, such as Grime's C-S-R (competitor, stress tolerator, ruderal) framework, can help to explain life history diversification in AM fungi, successional dynamics, and the spatial structure of AM fungal assemblages. Using a common life history classification framework for both plants and AM fungi could also help in predicting probable species associations in natural communities and increase our fundamental understanding of the interaction between land plants and AM fungi. Copyright © 2013 Elsevier Ltd. All rights reserved.

Columbia River White Sturgeon (Acipenser Transmontanus) Early Life History and Genertics Study, August 1, 1984 to December 31, 1985 Final Report.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brannon, Ernest L.

1985-12-01

Research on Columbia River white sturgeon has been directed at their early life history as it may apply to production and enhancement strategies for management of the species. The river environment in which sturgeon historically migrated, spawned, and reared has changed through development. Habitat changes are expected to precipitate genetic changes in the fish, as well as reduce the fitness in populations. Genetic analysis of samples taken from various locations over the length of the Columbia River have indicated that observed gene frequencies in all areas sampled were not in Hardy-Weinburg equilibrium, which could suggest that the general population ismore » experiencing perturbation in the system. Analysis thus far has exposed few differences between samples from the lower, middle, and upper portions of the system. Allelic differences were identified in fish from the Roosevelt Lake, which may be evidence of unique characteristics among fish from that general area.« less

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.…

The Early Years: "Life" Science

ERIC Educational Resources Information Center

Ashbrook, Peggy

2013-01-01

Talking about death as part of a life cycle is often ignored or spoken about in hushed tones in early childhood. Books with "life cycle" in the title often do not include the death of the living organism in the information about the cycle. The concept of a complete life cycle does not appear in "A Framework for K-12 Science…

The crowded life is a slow life: Population density and life history strategy.

PubMed

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

2017-05-01

The world population has doubled over the last half century. Yet, research on the psychological effects of human population density, once a popular topic, has decreased over the past few decades. Applying a fresh perspective to an old topic, we draw upon life history theory to examine the effects of population density. Across nations and across the U.S. states (Studies 1 and 2), we find that dense populations exhibit behaviors corresponding to a slower life history strategy, including greater future-orientation, greater investment in education, more long-term mating orientation, later marriage age, lower fertility, and greater parental investment. In Studies 3 and 4, experimentally manipulating perceptions of high density led individuals to become more future-oriented. Finally, in Studies 5 and 6, experimentally manipulating perceptions of high density seemed to lead to life-stage-specific slower strategies, with college students preferring to invest in fewer rather than more relationship partners, and an older MTurk sample preferring to invest in fewer rather than more children. This research sheds new insight on the effects of density and its implications for human cultural variation and society at large. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Life History Correlates of Ministerial Success

ERIC Educational Resources Information Center

Umeda, John K.; Frey, David H.

1974-01-01

Life history or biodata correlates of ministerial success were investigated for a group of 92 Seventh-Day Adventist ministers. Two significant bivariate correlations indicated that successful ministers chose their career later than less successful ones and that earning college expenses was predictive of success. (Author/HMV)

Fixation of slightly beneficial mutations: effects of life history.

PubMed

Vindenes, Yngvild; Lee, Aline Magdalena; Engen, Steinar; Saether, Bernt-Erik

2010-04-01

Recent studies of rates of evolution have revealed large systematic differences among organisms with different life histories, both within and among taxa. Here, we consider how life history may affect the rate of evolution via its influence on the fixation probability of slightly beneficial mutations. Our approach is based on diffusion modeling for a finite, stage-structured population with stochastic population dynamics. The results, which are verified by computer simulations, demonstrate that even with complex population structure just two demographic parameters are sufficient to give an accurate approximation of the fixation probability of a slightly beneficial mutation. These are the reproductive value of the stage in which the mutation first occurs and the demographic variance of the population. The demographic variance also determines what influence population size has on the fixation probability. This model represents a substantial generalization of earlier models, covering a large range of life histories.

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

Increased amygdala reactivity following early life stress: a potential resilience enhancer role.

PubMed

Yamamoto, Tetsuya; Toki, Shigeru; Siegle, Greg J; Takamura, Masahiro; Takaishi, Yoshiyuki; Yoshimura, Shinpei; Okada, Go; Matsumoto, Tomoya; Nakao, Takashi; Muranaka, Hiroyuki; Kaseda, Yumiko; Murakami, Tsuneji; Okamoto, Yasumasa; Yamawaki, Shigeto

2017-01-18

Amygdala hyper-reactivity is sometimes assumed to be a vulnerability factor that predates depression; however, in healthy people, who experience early life stress but do not become depressed, it may represent a resilience mechanism. We aimed to test these hypothesis examining whether increased amygdala activity in association with a history of early life stress (ELS) was negatively or positively associated with depressive symptoms and impact of negative life event stress in never-depressed adults. Twenty-four healthy participants completed an individually tailored negative mood induction task during functional magnetic resonance imaging (fMRI) assessment along with evaluation of ELS. Mood change and amygdala reactivity were increased in never-depressed participants who reported ELS compared to participants who reported no ELS. Yet, increased amygdala reactivity lowered effects of ELS on depressive symptoms and negative life events stress. Amygdala reactivity also had positive functional connectivity with the bilateral DLPFC, motor cortex and striatum in people with ELS during sad memory recall. Increased amygdala activity in those with ELS was associated with decreased symptoms and increased neural features, consistent with emotion regulation, suggesting that preservation of robust amygdala reactions may reflect a stress buffering or resilience enhancing factor against depression and negative stressful events.

Early-life conditions and health at older ages: The mediating role of educational attainment, family and employment trajectories.

PubMed

Arpino, Bruno; Gumà, Jordi; Julià, Albert

2018-01-01

We examine to what extent the effect of early-life conditions (health and socioeconomic status) on health in later life is mediated by educational attainment and life-course trajectories (fertility, partnership, employment). Using data from the Survey of Health, Ageing and Retirement in Europe (N = 12,034), we apply, separately by gender, multichannel sequence analysis and cluster analysis to obtain groups of similar family and employment histories. The KHB method is used to disentangle direct and indirect effects of early-life conditions on health. Early-life-conditions indirectly impact on health in later life as result of their influence on education and family and employment trajectories. For example, between 22% and 42% of the effect of low parental socio-economic status at childhood on the three considered health outcomes at older age is explained by educational attainment for women. Even higher percentages are found for men (35% - 57%). On the contrary, the positive effect of poor health at childhood on poor health at older ages is not significantly mediated by education and life-course trajectories. Education captures most of the mediating effect of parental socio-economic status. More specifically, between 66% and 75% of the indirect effect of low parental socio-economic status at childhood on the three considered health outcomes at older age is explained by educational attainment for women. Again, higher percentages are found for men (86% - 93%). Early-life conditions, especially socioeconomic status, influence family and employment trajectories indirectly through their impact on education. We also find a persistent direct impact of early-life conditions on health at older ages. Our findings demonstrate that early-life experiences influence education and life-course trajectories and health in later life, suggesting that public investments in children are expected to produce long lasting effects on people's lives throughout the different phases of their

On the Psychometric Study of Human Life History Strategies.

PubMed

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

2017-01-01

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

Effects of predispersal insect seed predation on the early life history stages of a rare cold sand-desert legume.

PubMed

Han, Yi J; Baskin, Jerry M; Tan, Dun Y; Baskin, Carol C; Wu, Ming Y

2018-02-19

Seed predation by insects is common in seeds of Fabaceae (legume) species with physical dormancy (PY). However, the consequences of insect seed predation on the life history of legumes with PY have been little studied. In the largest genus of seed plants, Astragalus (Fabaceae), only one study has tested the effects of insect predation on germination, and none has tested it directly on seedling survival. Thus, we tested the effects of insect predation on seed germination and seedling growth and survival of Astragalus lehmannianus, a central Asian sand-desert endemic. Under laboratory conditions, seeds lightly predated in the natural habitat of this perennial legume germinated to a much higher percentage than intact seeds, and seedlings from predated and nonpredated seeds survived and grew about equally well. Further, in contrast to our prediction seedlings from predated seeds that germinated "out-of-season" under near-natural conditions in NW China survived over winter. The implication of our results is that individual plants from predated seeds that germinate early (in our case autumn) potentially have a fitness advantage over those from nonpredated seeds, which delay germination until spring of a subsequent year.

Early Life Stress: Effects on the Regulation of Anxiety Expression in Children and Adolescents.

PubMed

Burkholder, Amanda R; Koss, Kalsea J; Hostinar, Camelia E; Johnson, Anna E; Gunnar, Megan R

2016-11-01

This study examined children's ( N = 79; 9-10 years) and adolescents' ( N = 82; 15-16 years) ability to regulate their emotion expressions of anxiety as they completed a modified version of the Trier Social Stress Test for Children (TSST-C). Approximately half in each age group were internationally adopted from institutional care ( N = 79) and half were non-adopted, age-matched peers ( N = 82). Institutional care was viewed as a form of early life stress. Coders who were reliable and blind to group status watched videos of the session to assess anxiety expressions using the Child and Adolescent Stress and Emotion Scale developed for this study. Children exhibited more expressions of anxiety than adolescents, and youth adopted from institutions showed more expressions of anxiety than their non-adopted counterparts. The role of early life stress on observed anxiety expressions remained significant after controlling for differences in age, physiological stress responses measured through salivary cortisol reactivity, and self-reports of stress during the TSST-C. This suggests possible deficits in the regulation of expressive behavior for youth with early life stress histories, which cannot be explained by experiencing the task as more stressful.

Early Life Stress: Effects on the Regulation of Anxiety Expression in Children and Adolescents

PubMed Central

Burkholder, Amanda R; Koss, Kalsea J.; Hostinar, Camelia E; Johnson, Anna E.; Gunnar, Megan R

2017-01-01

This study examined children’s (N = 79; 9–10 years) and adolescents’ (N = 82; 15–16 years) ability to regulate their emotion expressions of anxiety as they completed a modified version of the Trier Social Stress Test for Children (TSST-C). Approximately half in each age group were internationally adopted from institutional care (N = 79) and half were non-adopted, age-matched peers (N = 82). Institutional care was viewed as a form of early life stress. Coders who were reliable and blind to group status watched videos of the session to assess anxiety expressions using the Child and Adolescent Stress and Emotion Scale developed for this study. Children exhibited more expressions of anxiety than adolescents, and youth adopted from institutions showed more expressions of anxiety than their non-adopted counterparts. The role of early life stress on observed anxiety expressions remained significant after controlling for differences in age, physiological stress responses measured through salivary cortisol reactivity, and self-reports of stress during the TSST-C. This suggests possible deficits in the regulation of expressive behavior for youth with early life stress histories, which cannot be explained by experiencing the task as more stressful. PMID:28584408

Reproductive effects on skeletal health in Shuar women of Amazonian Ecuador: a life history perspective.

PubMed

Madimenos, Felicia C; Snodgrass, J Josh; Liebert, Melissa A; Cepon, Tara J; Sugiyama, Lawrence S

2012-01-01

Clinical and epidemiological research suggest that bone mineral density (BMD) in women is shaped by various reproductive factors such as parity and lactation patterns. However, the extent of these effects on BMD remains unclear because of contradictory findings and a focus on industrialized populations. Because fertility patterns in these groups are vastly different than those of women from non-Western, subsistence populations, our current understanding of the reproductive effects on skeletal health is incomplete. Using a life history perspective, this study examines the relationship between reproductive factors and bone density among women from the Indigenous Shuar population, an Amazonian Ecuadorian forager-horticulturalist group. This preliminary, cross-sectional study included 130 premenopausal and postmenopausal women (14-86 years old) from the Morona-Santiago region of Ecuador. Anthropometrics were recorded, as was estimated BMD using a calcaneal ultrasonometer. A reproductive history questionnaire was administered that included questions regarding menarche, parity, lactation patterns, and menopause. Among postmenopausal women, early menarche and greater stature were significantly associated with higher bone density values. Among premenopausal women, few significant relationships between bone values and reproductive variables were documented; effects of lactation appeared to be transient and restored following weaning. Although preliminary and not based on longitudinal data, these findings suggest that the effects of reproduction are transient as the system of calcium homeostasis in premenopausal women efficiently restores the bone loss that results from metabolically active reproductive states. Further, this research suggests that the timing of early life history events may canalize bone density phenotype. Copyright © 2012 Wiley Periodicals, Inc.

Behavioural mediators of genetic life-history trade-offs: a test of the pace-of-life syndrome hypothesis in field crickets.

PubMed

Santostefano, Francesca; Wilson, Alastair J; Niemelä, Petri T; Dingemanse, Niels J

2017-10-11

The pace-of-life syndrome (POLS) hypothesis predicts associations between life history and 'risky' behaviours. Individuals with 'fast' lifestyles should develop faster, reproduce earlier, exhibit more risk-prone behaviours, and die sooner than those with 'slow' lifestyles. While support for POLS has been equivocal to date, studies have relied on individual-level (phenotypic) patterns in which genetic trade-offs may be masked by environmental effects on phenotypes. We estimated genetic correlations between life history (development, lifespan, size) and risky behaviours (exploration, aggression) in a pedigreed population of Mediterranean field crickets ( Gryllus bimaculatus ). Path analyses showed that behaviours mediated some genetic relationships between life history traits, though not those involved in trade-offs. Thus, while specific predictions of POLS theory were not supported, genetic integration of behaviour and life history was present. This implies a major role for risky behaviours in life history evolution. © 2017 The Author(s).

Life-history variation of a neotropical thrush challenges food limitation theory

USGS Publications Warehouse

Ferretti, V.; Llambias, P.E.; Martin, T.E.

2005-01-01

Since David Lack first proposed that birds rear as many young as they can nourish, food limitation has been accepted as the primary explanation for variation in clutch size and other life-history traits in birds. The importance of food limitation in life-history variation, however, was recently questioned on theoretical grounds. Here, we show that clutch size differences between two populations of a neotropical thrush were contrary to expectations under Lack's food limitation hypothesis. Larger clutch sizes were found in a population with higher nestling starvation rate (i.e. greater food limitation). We experimentally equalized clutches between populations to verify this difference in food limitation. Our experiment confirmed greater food limitation in the population with larger mean clutch size. In addition, incubation bout length and nestling growth rate were also contrary to predictions of food limitation theory. Our results demonstrate the inability of food limitation to explain differences in several life-history traits: clutch size, incubation behaviour, parental feeding rate and nestling growth rate. These life-history traits were better explained by inter-population differences in nest predation rates. Food limitation may be less important to life history evolution in birds than suggested by traditional theory. ?? 2005 The Royal Society.

Adler's psychology (of use) today: personal history of traumatic life events as a self-handicapping strategy.

PubMed

DeGree, C E; Snyder, C R

1985-06-01

We investigated the hypothesis that the reporting of a history of traumatic life events may serve as a strategy to control attributions about performance in an evaluative setting (i.e., self-handicapping). Following from Alfred Adler's early theorization in the psychology of use, as well as more recent theory and research on self-handicapping, we predicted that individuals would emphasize the adversity of events and experiences in their background when an uncertain evaluation was expected and when a traumatic background would serve as a suitable excuse for potential failure. Results generally supported the hypothesized self-protective reporting of traumatic life events.

The heroines of their own stories: Insights from the use of life history drawings in research with a transnational migrant community

PubMed Central

Hirsch, Jennifer S.; Philbin, Morgan M.

2016-01-01

In this paper, we discuss how Life History Drawings can serve as a valuable method for global health research. The introduction discusses qualitative approaches to concepts such as reliability, validity and triangulation, and situates the use of participatory visual methods within the broader field of participatory research. The paper reports on an experience using life history drawings as part of extended ethnographic research in rural Mexico and among Mexican migrants living in Atlanta. The primary method for that parent project was comparative ethnographic research, which included life histories collected from 13 pairs of women over 15 months of participant observation. Early in the research, the drawings contributed to a major reorientation in the direction of the research project. The insights generated through analysis of the life history drawings exemplify how this participatory research technique can direct attention to social processes that feel salient to community members. In this case, they called attention to the enormity of social change in this community over one generation, reorienting the study from one focused on change causes by migration to one that focused on two trajectories of change: generational and migration-related. PMID:27109003

Sex differences in cognitive ageing: testing predictions derived from life-history theory in a dioecious nematode.

PubMed

Zwoinska, Martyna K; Kolm, Niclas; Maklakov, Alexei A

2013-12-01

Life-history theory maintains that organisms allocate limited resources to different traits to maximize fitness. Learning ability and memory are costly and known to trade-off with longevity in invertebrates. However, since the relationship between longevity and fitness often differs between the sexes, it is likely that sexes will differentially resolve the trade-off between learning and longevity. We used an established associative learning paradigm in the dioecious nematode Caenorhabditis remanei, which is sexually dimorphic for lifespan, to study age-related learning ability in males and females. In particular, we tested the hypothesis that females (the shorter-lived sex) show higher learning ability than males early in life but senesce faster. Indeed, young females outperformed young males in learning a novel association between an odour (butanone) and food (bacteria). However, while learning ability and offspring production declined rapidly with age in females, males maintained high levels of these traits until mid-age. These results not only demonstrate sexual dimorphism in age-related learning ability but also suggest that it conforms to predictions derived from the life-history theory. © 2013.

Ontogenetic and life history trait changes associated with convergent ecological specializations in extinct ungulate mammals

PubMed Central

Gomes Rodrigues, Helder; Billet, Guillaume

2017-01-01

Investigating life history traits in mammals is crucial to understand their survival in changing environments. However, these parameters are hard to estimate in a macroevolutionary context. Here we show that the use of dental ontogenetic parameters can provide clues to better understand the adaptive nature of phenotypic traits in extinct species such as South American notoungulates. This recently extinct order of mammals evolved in a context of important geological, climatic, and environmental variations. Interestingly, notoungulates were mostly herbivorous and acquired high-crowned teeth very early in their evolutionary history. We focused on the variations in crown height, dental eruption pattern, and associated body mass of 69 notoungulate taxa, placed in their phylogenetic and geological contexts. We showed that notoungulates evolved higher crowns several times between 45 and 20 Ma, independently of the variation in body mass. Interestingly, the independent acquisitions of ever-growing teeth were systematically accompanied by eruption of molars faster than permanent premolars. These repeated associations of dental innovations have never been documented for other mammals and raise questions on their significance and causal relationships. We suggest that these correlated changes could originate from ontogenetic adjustments favored by structural constraints, and may indicate accelerated life histories. Complementarily, these more durable and efficient dentitions could be selected to cope with important ingestions of abrasive particles in the context of intensified volcanism and increasing aridity. This study demonstrates that assessing both life history and ecological traits allows a better knowledge of the specializations of extinct mammals that evolved under strong environmental constraints. PMID:28096389

The influence of living conditions in early life on life satisfaction in old age.

PubMed

Deindl, Christian

2013-03-01

This article examines the influence of living conditions in early life on life satisfaction in old age in eleven Western European countries. It combines the influence of individual conditions, for example housing and family background, with country characteristics in the decade of birth. Using pooled data from the second and third wave of the Survey of Health, Ageing and Retirement in Europe, multilevel models show that early life living conditions have an influence on life satisfaction in old age. Furthermore, interaction effects between current and past living conditions show that adverse living conditions strengthen the effect of early life on life satisfaction in later life and therefore are an indication of cumulative inequality over the life course. Copyright © 2012 Elsevier Ltd. All rights reserved.

A review of noble gas geochemistry in relation to early Earth history

NASA Technical Reports Server (NTRS)

Kurz, M. D.

1985-01-01

One of the most fundamental noble gas constraints on early Earth history is derived from isotopic differences in (129)Xe/(130)Xe between various terrestrial materials. The short half life (17 m.y.) of extinct (129I, parent of (129)Xe, means that these differences must have been produced within the first 100 m.y. after terrestrial accretion. The identification of large anomalies in (129)Xe/(130)Xe in mid ocean ridge basalts (MORB), with respect to atmospheric xenon, suggests that the atmosphere and upper mantle have remained separate since that time. This alone is a very strong argument for early catastrophic degassing, which would be consistent with an early fractionation resulting in core formation. However, noble gas isotopic systematics of oceanic basalts show that the mantle cannot necessarily be regarded as a homogeneous system, since there are significant variations in (3)He/(4)He, (40)Ar/(36)Ar, and (129)Xe/(130)Xe. Therefore, the early degassing cannot be considered to have acted on the whole mantle. The specific mechanisms of degassing, in particular the thickness and growth of the early crust, is an important variable in understanding present day noble gas inventories. Another constraint can be obtained from rocks that are thought to be derived from near the lithosphere asthenosphere boundary: ultramafic xenoliths.

Life-history correlations with seasonal cold hardiness in maritime pine.

PubMed

Prada, Eva; Climent, José; Alía, Ricardo; Díaz, Raquel

2016-12-01

Plants have developed mechanisms to withstand stressful environmental conditions, but the high energetic cost of these mechanisms may involve exchanges with other key functions. While trade-offs between cold hardiness and growth rates are a general assumption, we lack information regarding genetically based trade-offs between cold hardiness and other life-history traits. Such information has strong implications for tree conservation and breeding, especially in the context of ongoing climate change. We used a common garden progeny test to examine the relationships between seasonal cold hardiness and life-history traits of growth, reproduction, juvenile ontogeny, and phenology in 75 families of six maritime pine (Pinus pinaster Ait.) populations, three of continental and three of coastal origins. We found a clear differentiation among populations with regard to cold hardiness and life-history traits. Two continental Iberian populations showed high cold tolerance and slower growth, but faster ontogenetic development in relation to both vegetative heteroblastic change in juveniles and the onset of female reproduction. The coastal populations displayed the opposite behavior, while the continental Moroccan population presented a unique combination of traits. We confirmed trade-offs between cold-hardiness and growth at the population level, but not within populations. There were no trade-offs with other life-history traits at either level. Relevant local adaptation syndromes were identified in the relationship between cold hardiness and life-history traits. These should be considered in developing tree management guidelines aimed at increasing productivity or adaptability under the expected conditions of climate change. © 2016 Botanical Society of America.

Impact Constraints on Major Events in Early Mars History

NASA Technical Reports Server (NTRS)

Frey, H. V.

2004-01-01

MOLA data have revealed a large population of "Quasi-Circular Depressions" (QCDs) with little or no visible expression in image data. These likely buried impact basins have important implications for the age of the lowland crust, how that compares with original highland crust, and when and how the crustal dichotomy may have formed. The buried lowlands are of Early Noachian age, likely slightly younger than the buried highlands but older than the exposed (visible) highland surface. A depopulation of large visible basins at diameters 800 to 1300 km suggests some global scale event early in martian history, maybe related to the formation of the lowlands and/or the development of Tharsis. A suggested early disappearance of the global magnetic field can be placed within a temporal sequence of formation of the very largest impact basins. The global field appears to have disappeared at about the time the lowlands formed. It seems likely the topographic crustal dichotomy was produced very early in martian history by processes which operated very quickly. Thus there appears to have been a northern lowland throughout nearly all of martian history, predating the last of the really large impacts (Hellas, Argyre and Isidis) and their likely very significant environmental consequences.

History of the Earth - The History of Life

NASA Astrophysics Data System (ADS)

Rozanov, A. Yu.

2017-05-01

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

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.

Apparent annual survival estimates of tropical songbirds better reflect life history variation when based on intensive field methods

USGS Publications Warehouse

Martin, Thomas E.; Riordan, Margaret M.; Repin, Rimi; Mouton, James C.; Blake, William M.

2017-01-01

AimAdult survival is central to theories explaining latitudinal gradients in life history strategies. Life history theory predicts higher adult survival in tropical than north temperate regions given lower fecundity and parental effort. Early studies were consistent with this prediction, but standard-effort netting studies in recent decades suggested that apparent survival rates in temperate and tropical regions strongly overlap. Such results do not fit with life history theory. Targeted marking and resighting of breeding adults yielded higher survival estimates in the tropics, but this approach is thought to overestimate survival because it does not sample social and age classes with lower survival. We compared the effect of field methods on tropical survival estimates and their relationships with life history traits.LocationSabah, Malaysian Borneo.Time period2008–2016.Major taxonPasseriformes.MethodsWe used standard-effort netting and resighted individuals of all social and age classes of 18 tropical songbird species over 8 years. We compared apparent survival estimates between these two field methods with differing analytical approaches.ResultsEstimated detection and apparent survival probabilities from standard-effort netting were similar to those from other tropical studies that used standard-effort netting. Resighting data verified that a high proportion of individuals that were never recaptured in standard-effort netting remained in the study area, and many were observed breeding. Across all analytical approaches, addition of resighting yielded substantially higher survival estimates than did standard-effort netting alone. These apparent survival estimates were higher than for temperate zone species, consistent with latitudinal differences in life histories. Moreover, apparent survival estimates from addition of resighting, but not from standard-effort netting alone, were correlated with parental effort as measured by egg temperature across species

Early life adversity influences stress response association with smoking relapse.

PubMed

al'Absi, Mustafa; Lemieux, Andrine; Westra, Ruth; Allen, Sharon

2017-11-01

We examined the hypothesis that stress-related blunting of cortisol in smokers is particularly pronounced in those with a history of severe life adversity. The two aims of this study were first to examine hormonal, craving, and withdrawal symptoms during ad libitum smoking and after the first 24 h of abstinence in smokers who experienced high or low levels of adversity. Second, we sought to examine the relationship between adversity and hypothalamic-pituitary-adrenal (HPA) hormones to predict relapse during the first month of a smoking cessation attempt. Hormonal and self-report measures were collected from 103 smokers (49 women) during ad libitum smoking and after the first 24 h of abstinence. HPA hormones were measured during baseline rest and in response to acute stress in both conditions. All smokers were interested in smoking cessation, and we prospectively used stress response measures to predict relapse during the first 4 weeks of the smoking cessation attempt. The results showed that high adversity was associated with higher distress and smoking withdrawal symptoms. High level of early life adversity was associated with elevated HPA activity, which was found in both salivary and plasma cortisol. Enhanced adrenocorticotropic hormone (ACTH) stress response was evident in high-adversity but not in low-adversity relapsers. This study demonstrated that early life adversity is associated with stress-related HPA responses. The study also demonstrated that, among smokers who experienced a high level of life adversity, heightened ACTH and cortisol responses were linked with increased risk for smoking relapse.

Dynamics of body time, social time and life history at adolescence.

PubMed

Worthman, Carol M; Trang, Kathy

2018-02-21

Recent opposing trends towards earlier physical maturation and later social maturation present a conundrum of apparent biological-social mismatch. Here we use life history analysis from evolutionary ecology to identify forces that drive these shifts. Together with findings in developmental science, our life history analysis indicates that adolescence is a distinctive period for biological embedding of culture. Ethnographic evidence shows that mass education is a novel feature of the globalizing cultural configurations of adolescence, which are driven by transformations in labour, livelihood and lifestyle. Evaluation of the life history trade-offs and sociocultural ecologies that are experienced by adolescents may offer a practical basis for enhancing their development.

Dynamics of body time, social time and life history at adolescence

NASA Astrophysics Data System (ADS)

Worthman, Carol M.; Trang, Kathy

2018-02-01

Recent opposing trends towards earlier physical maturation and later social maturation present a conundrum of apparent biological-social mismatch. Here we use life history analysis from evolutionary ecology to identify forces that drive these shifts. Together with findings in developmental science, our life history analysis indicates that adolescence is a distinctive period for biological embedding of culture. Ethnographic evidence shows that mass education is a novel feature of the globalizing cultural configurations of adolescence, which are driven by transformations in labour, livelihood and lifestyle. Evaluation of the life history trade-offs and sociocultural ecologies that are experienced by adolescents may offer a practical basis for enhancing their development.

Life history constrains biochemical development in the highly specialized odontocete echolocation system

PubMed Central

Koopman, Heather N; Zahorodny, Zoey P

2008-01-01

The vertebrate head has undergone enormous modification from the features borne by early ancestors. The growth of skull bones has been well studied in many species, yet little is known about corresponding soft tissue development. Among mammals, some of the most unusual examples of cranial evolution exist in the toothed whales (odontocetes). Specialized fat bodies in toothed whale heads play important roles in sound transmission and reception. These fat bodies contain unique endogenous lipids, with favourable acoustic properties, arranged in highly organized, three-dimensional patterns. We link variation in developmental rates of acoustic fats with life-history strategy, using bottlenose dolphins and harbour porpoises. Porpoise acoustic fats attain adult configurations earlier (less than 1 year) and at a faster pace than dolphins. The accelerated lipid accumulation in porpoises reflects the earlier need for fully functional echolocation systems. Dolphins enjoy 3–6 years of maternal care; porpoises must achieve total independence by approximately nine months. Further, a stereotypic ‘blueprint’ for the spatial distribution of lipids is established prior to birth, demonstrating the highly conserved nature of the intricate biochemical arrangement in acoustic tissues. This system illustrates an unusual case of soft tissue development being constrained by life history, rather than the more commonly observed mechanistic or phyletic constraints. PMID:18611851

The Early History of Bioenergy

NASA Astrophysics Data System (ADS)

Radu, Popa

Energy is most commonly defined as the potential to do work. The maintenance of the living state requires a constant flow of energy through the system. The concept of energy is not easily implemented in computational models of life and is therefore often ignored in artificial life models. Some models even regard as irrelevant the energetic problematic (dissipation, irreversibility, couplings, energy currencies), in the physical realization of a biological system" (Ruiz-Mirazo et al. 1998). Examples of such models are Rosen's (M,R)-system, Varela's autopoietic models, Kauffman's autocatalytic set, and Fontana's algorithmic chemistry (see Appendix A). However, many origin-of-life theories maintain the primordial importance of energy for early life. Although everyone accepts that energetic constraints are important when describing material-based living systems, a problem arises when we have to consider whether or not they affect the very logic of the organization (Morán et al. 1999). It is argued here that energy considerations are not only primordial, but intimately related to the essence of life as well.

Proinflammatory milieu in combat-related PTSD is independent of depression and early life stress.

PubMed

Lindqvist, Daniel; Wolkowitz, Owen M; Mellon, Synthia; Yehuda, Rachel; Flory, Janine D; Henn-Haase, Clare; Bierer, Linda M; Abu-Amara, Duna; Coy, Michelle; Neylan, Thomas C; Makotkine, Iouri; Reus, Victor I; Yan, Xiaodan; Taylor, Nicole M; Marmar, Charles R; Dhabhar, Firdaus S

2014-11-01

Chronic inflammation may be involved in combat-related post-traumatic stress disorder (PTSD) and may help explain comorbid physical diseases. However, the extent to which combat exposure per se, depression, or early life trauma, all of which are associated with combat PTSD, may confound the relationship between PTSD and inflammation is unclear. We quantified interleukin (IL)-6, IL-1β, tumor necrosis factor (TNF)-α, interferon (IFN)-γ, and C-reactive protein (CRP) in 51 combat-exposed males with PTSD and 51 combat-exposed males without PTSD, and assessed PTSD and depression severity as well as history of early life trauma. To decrease the possibility of Type I errors, we summed standardized scores of IL-1β, IL-6, TNFα, IFNγ and CRP into a total "pro-inflammatory score". PTSD symptom severity was assessed with the Clinician Administered PTSD Scale (CAPS) rating scale. Subjects with PTSD had significantly higher pro-inflammatory scores compared to combat-exposed subjects without PTSD (p=0.006), and even after controlling for early life trauma, depression diagnosis and severity, body mass index, ethnicity, education, asthma/allergies, time since combat and the use of possibly confounding medications (p=0.002). Within the PTSD group, the pro-inflammatory score was not significantly correlated with depressive symptom severity, CAPS total score, or with the number of early life traumas. Combat-related PTSD in males is associated with higher levels of pro-inflammatory cytokines, even after accounting for depression and early life trauma. These results, from one of the largest studies of inflammatory cytokines in PTSD to date, suggest that immune activation may be a core element of PTSD pathophysiology more so than a signature of combat exposure alone. Copyright © 2014. Published by Elsevier Inc.

Interacting effects of genetic variation for seed dormancy and flowering time on phenology, life history, and fitness of experimental Arabidopsis thaliana populations over multiple generations in the field.

PubMed

Taylor, Mark A; Cooper, Martha D; Sellamuthu, Reena; Braun, Peter; Migneault, Andrew; Browning, Alyssa; Perry, Emily; Schmitt, Johanna

2017-10-01

Major alleles for seed dormancy and flowering time are well studied, and can interact to influence seasonal timing and fitness within generations. However, little is known about how this interaction controls phenology, life history, and population fitness across multiple generations in natural seasonal environments. To examine how seed dormancy and flowering time shape annual plant life cycles over multiple generations, we established naturally dispersing populations of recombinant inbred lines of Arabidopsis thaliana segregating early and late alleles for seed dormancy and flowering time in a field experiment. We recorded seasonal phenology and fitness of each genotype over 2 yr and several generations. Strong seed dormancy suppressed mid-summer germination in both early- and late-flowering genetic backgrounds. Strong dormancy and late-flowering genotypes were both necessary to confer a winter annual life history; other genotypes were rapid-cycling. Strong dormancy increased within-season fecundity in an early-flowering background, but decreased it in a late-flowering background. However, there were no detectable differences among genotypes in population growth rates. Seasonal phenology, life history, and cohort fitness over multiple generations depend strongly upon interacting genetic variation for dormancy and flowering. However, similar population growth rates across generations suggest that different life cycle genotypes can coexist in natural populations. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

Early history of scapular fractures.

PubMed

Bartoníček, Jan; Kozánek, Michal; Jupiter, Jesse B

2016-01-01

The first to use the term Scapula was Vesalius (1514-1564) and thus it has remained ever since. Probably the oldest injured scapula, from 250 million years ago, was described by Chinese authors of a skeletal examination of a fossilised remains of a dinosaur Yangchuanosaurus hepingensis. In humans, the oldest known scapular fractures date back to the prehistoric and early historic times. In ancient times, a fracture of acromion was described in the treatises of Hippocrates. Early modern history of the treatment of scapular fractures is closely interlinked with the history of the French surgery. The first to point out the existence of these fractures were Petit, Du Verney and Desault in the 18th century. The first study devoted solely to scapular fractures was published by Traugott Karl August Vogt in 1799. Thomas Callaway published in 1849 an extensive dissertation on injuries to the shoulder girdle, in which he discussed a number of cases known at that time. The first radiograph of a scapular fracture was published by Petty in 1907. Mayo Robson (1884), Lambotte (1913) and Lane (1914) were pioneers in the surgical treatment of these fractures, followed in 1923 by the French surgeons Lenormat, Dujarrier and Basset. The first internal fixation of the glenoid fossa, including a radiograph, was published by Fischer in 1939.

Early Life Stress, Mood, and Anxiety Disorders.

PubMed

Syed, Shariful A; Nemeroff, Charles B

2017-02-01

Early life stress has been shown to exert profound short- and long-term effects on human physiology both in the central nervous system and peripherally. Early life stress has demonstrated clear association with many psychiatric disorders including major depression, posttraumatic stress disorder, and bipolar disorder. The Diagnostic and Statistics Manuel of Mental Disorders (DSM) diagnostic categorical system has served as a necessary framework for clinical service, delivery, and research, however has not been completely matching the neurobiological research perspective. Early life stress presents a complex dynamic featuring a wide spectrum of physiologic alterations: from epigenetic alterations, inflammatory changes, to dysregulation of the hypothalamic pituitary axis and has further added to the challenge of identifying biomarkers associated with psychiatric disorders. The National Institute of Mental Health's proposed Research Domain Criteria initiative incorporates a dimensional approach to assess discrete domains and constructs of behavioral function that are subserved by identifiable neural circuits. The current neurobiology of early life stress is reviewed in accordance with dimensional organization of Research Domain Criteria matrix and how the findings as a whole fit within the Research Domain Criteria frameworks.

Teaching in the Field: What Teacher Professional Life Histories Tell About How They Learn to Teach in the Outdoor Learning Environment

NASA Astrophysics Data System (ADS)

Feille, Kelly K.

2017-06-01

This research investigates the professional life histories of upper elementary science teachers who were identified as effective both within the classroom and in the outdoor learning environment (OLE). The narratives of five teachers, collected through semistructured and open-ended interviews, provided the data for the study. Professional life histories were constructed for each teacher participant and an analysis of the teacher narratives identified the themes of teacher development across the voices of the participants. Narrative reasoning was used to unify those themes into a hypothetical professional life history as reported in this manuscript. Implications of this research can be realized for stakeholders in the preparation of pre-service teachers as well as the development of in-service teachers. Future research regarding the early induction years of new teachers, impacts of inclusion of the OLE in pre-service teacher instruction, and teacher experiences regarding professional development relating to efforts to include the OLE in formal education should be investigated.

From Suns to Life: A Chronological Approach to the History of Life on Earth 4. Building of a Habitable Planet

NASA Astrophysics Data System (ADS)

Martin, Hervé; Albarède, Francis; Claeys, Philippe; Gargaud, Muriel; Marty, Bernard; Morbidelli, Alessandro; Pinti, Daniele L.

2006-06-01

Except the old Jack Hills zircon crystals, it does not exit direct record of the first 500 Ma of the Earth history. Consequently, the succession of events that took place during this period is only indirectly known through geochemistry, comparison with other telluric planets, and numerical modelling. Just after planetary accretion several episodes were necessary in order to make life apparition and development possible and to make the Earth surface habitable. Among these stages are: the core differentiation, the formation of a magma ocean, the apparition of the first atmosphere, oceans and continents as well as the development of magnetic field and of plate tectonics. In the same time, Earth has been subject to extraterrestrial events such as the Late Heavy Bombardment (LHB) between 3.95 and 3.8 Ga. Since 4.4 4.3 Ga, the conditions for pre-biotic chemistry and appearance of life were already met (liquid water, continental crust, no strong meteoritic bombardment, etc...). This does not mean that life existed as early, but this demonstrates that all necessary conditions assumed for life development were already present on Earth.

Learning Early Twentieth-Century History through First-Person Interviews

ERIC Educational Resources Information Center

Lark, Lisa A.

2007-01-01

For many of the students in the author's American history class, early twentieth-century American history seems far removed from their daily lives. Being first and second-generation American citizens, many of the students do not have the luxury of hearing grandparents and great-grandparents telling stories about FDR and Henry Ford. More…

Predicting life-history adaptations to pollutants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maltby, L.

1995-12-31

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

Seedling architecture and life history evolution in pines

Treesearch

Steven H. Strauss; F. Thomas Ledig

1985-01-01

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

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

Evolution of monogamy, paternal investment, and female life history in Peromyscus.

PubMed

Jašarević, Eldin; Bailey, Drew H; Crossland, Janet P; Dawson, Wallace D; Szalai, Gabor; Ellersieck, Mark R; Rosenfeld, Cheryl S; Geary, David C

2013-02-01

The timing of reproductive development and associated trade-offs in quantity versus quality of offspring produced across the life span are well documented in a wide range of species. The relation of these aspects of maternal life history to monogamy and paternal investment in offspring is not well studied in mammals, due in part to the rarity of the latter. By using five large, captive-bred populations of Peromyscus species that range from promiscuous mating with little paternal investment (P. maniculatus bairdii) to social and genetic monogamy with substantial paternal investment (P. californicus insignis), we modeled the interaction between monogamy and female life history. Monogamy and high paternal investment were associated with smaller litter size, delayed maternal reproduction that extended over a longer reproductive life span, and larger, higher quality offspring. The results suggest monogamy and paternal investment can alter the evolution of female life-history trajectories in mammals. PsycINFO Database Record (c) 2013 APA, all rights reserved

Reduced resistance to oxidative stress during reproduction as a cost of early-life stress.

PubMed

Zimmer, Cédric; Spencer, Karen A

2015-05-01

Stress exposure during early-life development can have long-term consequences for a variety of biological functions including oxidative stress. The link between early-life stress and oxidative balance is beginning to be explored and previous studies have focused on this link in adult non-breeding or immature individuals. However, as oxidative stress is considered as the main physiological mechanism underlying the trade-off between self-maintenance and investment in reproduction, it is necessary to look at the consequences of early-life stress on oxidative status during reproduction. Here, we investigated the effects of exposure to pre- and/or post-natal stress on oxidative balance during reproduction under benign or stressful environmental conditions in an avian model species, the Japanese quail. We determined total antioxidant status (TAS), total oxidant status (TOS) and resistance to a free-radical attack in individual exposed to pre-natal stress, post-natal stress or both and in control individuals exposed to none of the stressors. TAS levels decreased over time in all females that reproduced under stressful conditions. TOS decreased between the beginning and the end of reproductive period in pre-natal control females. In all females, resistance to a free-radical attack decreased over the reproductive event but this decrease was more pronounced in females from a pre-natal stress development. Our results suggest that pre-natal stress may be associated with a higher cost of reproduction in terms of oxidative stress. These results also confirm that early-life stress can be associated with both benefits and costs depending of the life-history stage or environmental context. Copyright © 2014 Elsevier Inc. All rights reserved.

Assembling the dodo in early modern natural history.

PubMed

Lawrence, Natalie

2015-09-01

This paper explores the assimilation of the flightless dodo into early modern natural history. The dodo was first described by Dutch sailors landing on Mauritius in 1598, and became extinct in the 1680s or 1690s. Despite this brief period of encounter, the bird was a popular subject in natural-history works and a range of other genres. The dodo will be used here as a counterexample to the historical narratives of taxonomic crisis and abrupt shifts in natural history caused by exotic creatures coming to Europe. Though this bird had a bizarre form, early modern naturalists integrated the dodo and other flightless birds through several levels of conceptual categorization, including the geographical, morphological and symbolic. Naturalists such as Charles L'Ecluse produced a set of typical descriptive tropes that helped make up the European dodo. These long-lived images were used for a variety of symbolic purposes, demonstrated by the depiction of the Dutch East India enterprise in Willem Piso's 1658 publication. The case of the dodo shows that, far from there being a dramatic shift away from emblematics in the seventeenth century, the implicit symbolic roles attributed to exotic beasts by naturalists constructing them from scant information and specimens remained integral to natural history.

Migration and HIV risk: Life histories of Mexican-born men living with HIV in North Carolina

PubMed Central

Mann, Lilli; Valera, Erik; Hightow-Weidman, Lisa B.; Barrington, Clare

2015-01-01

Latino men in the Southeastern USA are disproportionately affected by HIV, but little is known about how the migration process influences HIV-related risk. In North Carolina (NC), a relatively new immigrant destination, Latino men are predominantly young and from Mexico. We conducted 31 iterative life history interviews with 15 Mexican-born men living with HIV. We used holistic content narrative analysis methods to examine HIV vulnerability in the context of migration and to identify important turning points. Major themes included the prominence of traumatic early life experiences, migration as an ongoing process rather than a finite event, and HIV diagnosis as a final turning point in migration trajectories. Findings provide a nuanced understanding of HIV vulnerability throughout the migration process and have implications including the need for bi-national HIV prevention approaches, improved outreach around early testing and linkage to care, and attention to mental health. PMID:24866206

Life history variation is maintained by fitness trade-offs and negative frequency-dependent selection.

PubMed

Christie, Mark R; McNickle, Gordon G; French, Rod A; Blouin, Michael S

2018-04-24

The maintenance of diverse life history strategies within and among species remains a fundamental question in ecology and evolutionary biology. By using a near-complete 16-year pedigree of 12,579 winter-run steelhead ( Oncorhynchus mykiss ) from the Hood River, Oregon, we examined the continued maintenance of two life history traits: the number of lifetime spawning events (semelparous vs. iteroparous) and age at first spawning (2-5 years). We found that repeat-spawning fish had more than 2.5 times the lifetime reproductive success of single-spawning fish. However, first-time repeat-spawning fish had significantly lower reproductive success than single-spawning fish of the same age, suggesting that repeat-spawning fish forego early reproduction to devote additional energy to continued survival. For single-spawning fish, we also found evidence for a fitness trade-off for age at spawning: older, larger males had higher reproductive success than younger, smaller males. For females, in contrast, we found that 3-year-old fish had the highest mean lifetime reproductive success despite the observation that 4- and 5-year-old fish were both longer and heavier. This phenomenon was explained by negative frequency-dependent selection: as 4- and 5-year-old fish decreased in frequency on the spawning grounds, their lifetime reproductive success became greater than that of the 3-year-old fish. Using a combination of mathematical and individual-based models parameterized with our empirical estimates, we demonstrate that both fitness trade-offs and negative frequency-dependent selection observed in the empirical data can theoretically maintain the diverse life history strategies found in this population.

Are Expectations the Missing Link between Life History Strategies and Psychopathology?

PubMed

Kavanagh, Phillip S; Kahl, Bianca L

2018-01-01

Despite advances in knowledge and thinking about using life history theory to explain psychopathology there is still a missing link. That is, we all have a life history strategy, but not all of us develop mental health problems. We propose that the missing link is expectations - a mismatch between expected environmental conditions (including social) set by variations in life history strategies and the current environmental conditions. The mismatch hypothesis has been applied at the biological level in terms of health and disease and we believe that it can also be applied more broadly at the psychological level in terms of perceived expectations in the social environment and the resulting distress-psychopathology-that manifests when our expectations are not met.

Histoires de vie et Formation de Nouveaux Savoirs Vitaux (Life Histories and the Formation of New Life Knowledge).

ERIC Educational Resources Information Center

Pineau, Gaston

1994-01-01

Describes the use of life histories as a means for making sense of personal events and their application to education. Distinguishes three models for the use of life histories in education: the biographical model, the autobiographical model, and the dialectical model. (22 citations) (MAB)

Biomarkers as tracers for life on early earth and Mars

NASA Technical Reports Server (NTRS)

Simoneit, B. R.; Summons, R. E.; Jahnke, L. L.

1998-01-01

Biomarkers in geological samples are products derived from biochemical (natural product) precursors by reductive and oxidative processes (e.g., cholestanes from cholesterol). Generally, lipids, pigments and biomembranes are preserved best over longer geological times and labile compounds such as amino acids, sugars, etc. are useful biomarkers for recent times. Thus, the detailed characterization of biomarker compositions permits the assessment of the major contributing species of extinct and/or extant life. In the case of the early Earth, work has progressed to elucidate molecular structure and carbon isotropic signals preserved in ancient sedimentary rocks. In addition, the combination of bacterial biochemistry with the organic geochemistry of contemporary and ancient hydrothermal ecosystems permits the modeling of the nature, behavior and preservation potential of primitive microbial communities. This approach uses combined molecular and isotopic analyses to characterize lipids produced by cultured bacteria (representative of ancient strains) and to test a variety of culture conditions which affect their biosynthesis. On considering Mars, the biomarkers from lipids and biopolymers would be expected to be preserved best if life flourished there during its early history (3.5-4 x 10(9) yr ago). Both oxidized and reduced products would be expected. This is based on the inferred occurrence of hydrothermal activity during that time with the concomitant preservation of biochemically-derived organic matter. Both known biomarkers (i.e., as elucidated for early terrestrial samples and for primitive terrestrial microbiota) and novel, potentially unknown compounds should be characterized.

Asperger's syndrome and autism: comparison of early history and outcome.

PubMed

Szatmari, P; Bartolucci, G; Bremner, R

1989-12-01

The authors compared children with Asperger syndrome (AS) with high-functioning autistic children and psychiatric outpatient controls on measures of early history and outcome. In terms of their early history, the autistic probands showed more social impairment, a higher frequency of echolalia and pronoun reversal, and a more restricted range of activities than the AS group. Cluster analysis suggested refinements to the diagnostic criteria, which resulted in larger differences between the groups on these early history measures. In terms of their outcome, the autistic probands spent more time in special education classes but developed fewer accessory psychiatric symptoms than the AS children. It was clear, however, that there were no substantive, qualitative differences between the AS and autistic groups, indicating that AS should be considered a mild form of high-functioning autism. The inclusion of AS among the autistic spectrum of disorders has implications both for aetiological studies and for prevalence estimates of the pervasive developmental disorders.

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

Quantitative genetics of immunity and life history under different photoperiods.

PubMed

Hammerschmidt, K; Deines, P; Wilson, A J; Rolff, J

2012-05-01

Insects with complex life-cycles should optimize age and size at maturity during larval development. When inhabiting seasonal environments, organisms have limited reproductive periods and face fundamental decisions: individuals that reach maturity late in season have to either reproduce at a small size or increase their growth rates. Increasing growth rates is costly in insects because of higher juvenile mortality, decreased adult survival or increased susceptibility to parasitism by bacteria and viruses via compromised immune function. Environmental changes such as seasonality can also alter the quantitative genetic architecture. Here, we explore the quantitative genetics of life history and immunity traits under two experimentally induced seasonal environments in the cricket Gryllus bimaculatus. Seasonality affected the life history but not the immune phenotypes. Individuals under decreasing day length developed slower and grew to a bigger size. We found ample additive genetic variance and heritability for components of immunity (haemocyte densities, proPhenoloxidase activity, resistance against Serratia marcescens), and for the life history traits, age and size at maturity. Despite genetic covariance among traits, the structure of G was inconsistent with genetically based trade-off between life history and immune traits (for example, a strong positive genetic correlation between growth rate and haemocyte density was estimated). However, conditional evolvabilities support the idea that genetic covariance structure limits the capacity of individual traits to evolve independently. We found no evidence for G × E interactions arising from the experimentally induced seasonality.

Life history migrations of adult Yellowstone Cutthroat Trout in the upper Yellowstone River

USGS Publications Warehouse

Ertel, Brian D.; McMahon, Thomas E.; Koel, Todd M.; Gresswell, Robert E.; Burckhardt, Jason

2017-01-01

Knowledge of salmonid life history types at the watershed scale is increasingly recognized as a cornerstone for effective management. In this study, we used radiotelemetry to characterize the life history movements of Yellowstone Cutthroat Trout Oncorhynchus clarkii bouvieri in the upper Yellowstone River, an extensive tributary that composes nearly half of the drainage area of Yellowstone Lake. In Yellowstone Lake, Yellowstone Cutthroat Trout have precipitously declined over the past 2 decades primarily due to predation from introduced Lake Trout Salvelinus namaycush. Radio tags were implanted in 152 Yellowstone Cutthroat Trout, and their movements monitored over 3 years. Ninety-six percent of tagged trout exhibited a lacustrine–adfluvial life history, migrating upstream a mean distance of 42.6 km to spawn, spending an average of 24 d in the Yellowstone River before returning to Yellowstone Lake. Once in the lake, complex postspawning movements were observed. Only 4% of radio-tagged trout exhibited a fluvial or fluvial–adfluvial life history. Low prevalence of fluvial and fluvial–adfluvial life histories was unexpected given the large size of the upper river drainage. Study results improve understanding of life history diversity in potamodromous salmonids inhabiting relatively undisturbed watersheds and provide a baseline for monitoring Yellowstone Cutthroat Trout response to management actions in Yellowstone Lake.

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…

Fast–slow continuum and reproductive strategies structure plant life-history variation worldwide

PubMed Central

Salguero-Gómez, Roberto; Jones, Owen R.; Jongejans, Eelke; Blomberg, Simon P.; Hodgson, David J.; Mbeau-Ache, Cyril; Zuidema, Pieter A.; de Kroon, Hans; Buckley, Yvonne M.

2016-01-01

The identification of patterns in life-history strategies across the tree of life is essential to our prediction of population persistence, extinction, and diversification. Plants exhibit a wide range of patterns of longevity, growth, and reproduction, but the general determinants of this enormous variation in life history are poorly understood. We use demographic data from 418 plant species in the wild, from annual herbs to supercentennial trees, to examine how growth form, habitat, and phylogenetic relationships structure plant life histories and to develop a framework to predict population performance. We show that 55% of the variation in plant life-history strategies is adequately characterized using two independent axes: the fast–slow continuum, including fast-growing, short-lived plant species at one end and slow-growing, long-lived species at the other, and a reproductive strategy axis, with highly reproductive, iteroparous species at one extreme and poorly reproductive, semelparous plants with frequent shrinkage at the other. Our findings remain consistent across major habitats and are minimally affected by plant growth form and phylogenetic ancestry, suggesting that the relative independence of the fast–slow and reproduction strategy axes is general in the plant kingdom. Our findings have similarities with how life-history strategies are structured in mammals, birds, and reptiles. The position of plant species populations in the 2D space produced by both axes predicts their rate of recovery from disturbances and population growth rate. This life-history framework may complement trait-based frameworks on leaf and wood economics; together these frameworks may allow prediction of responses of plants to anthropogenic disturbances and changing environments. PMID:26699477

Fast-slow continuum and reproductive strategies structure plant life-history variation worldwide.

PubMed

Salguero-Gómez, Roberto; Jones, Owen R; Jongejans, Eelke; Blomberg, Simon P; Hodgson, David J; Mbeau-Ache, Cyril; Zuidema, Pieter A; de Kroon, Hans; Buckley, Yvonne M

2016-01-05

The identification of patterns in life-history strategies across the tree of life is essential to our prediction of population persistence, extinction, and diversification. Plants exhibit a wide range of patterns of longevity, growth, and reproduction, but the general determinants of this enormous variation in life history are poorly understood. We use demographic data from 418 plant species in the wild, from annual herbs to supercentennial trees, to examine how growth form, habitat, and phylogenetic relationships structure plant life histories and to develop a framework to predict population performance. We show that 55% of the variation in plant life-history strategies is adequately characterized using two independent axes: the fast-slow continuum, including fast-growing, short-lived plant species at one end and slow-growing, long-lived species at the other, and a reproductive strategy axis, with highly reproductive, iteroparous species at one extreme and poorly reproductive, semelparous plants with frequent shrinkage at the other. Our findings remain consistent across major habitats and are minimally affected by plant growth form and phylogenetic ancestry, suggesting that the relative independence of the fast-slow and reproduction strategy axes is general in the plant kingdom. Our findings have similarities with how life-history strategies are structured in mammals, birds, and reptiles. The position of plant species populations in the 2D space produced by both axes predicts their rate of recovery from disturbances and population growth rate. This life-history framework may complement trait-based frameworks on leaf and wood economics; together these frameworks may allow prediction of responses of plants to anthropogenic disturbances and changing environments.

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…

Columbia River White Sturgeon Genetics and Early Life History: Population Segregation and Juvenile Feeding Behavior, 1987 Final Report.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brannon, Ernest L.

1988-06-01

The geographic area of the genetics study broadly covered the distribution range of sturgeon in the Columbia from below Bonneville Dam at Ilwaco at Lake Roosevelt, the Upper Snake River, and the Kootenai River. The two remote river sections provided data important for enhancement considerations. There was little electrophoretic variation seen among individuals from the Kootenai River. Upper Snake river sturgeon showed a higher percentage of polymorphic loci than the Kootenai fish, but lower than the other areas in the Columbia River we sampled. Sample size was increased in both Lake Roosevelt and at Electrophoretic variation was specific to anmore » individual sampling area in several cases and this shaped our conclusions. The 1987 early life history studies concentrated on the feeding behavior of juvenile sturgeon. The chemostimulant components in prey attractive to sturgeon were examined, and the sensory systems utilized by foraging sturgeon were determined under different environmental conditions. These results were discussed with regard to the environmental changes that have occurred in the Columbia River. Under present river conditions, the feeding mechanism of sturgeon is more restricted to certain prey types, and their feeding range may be limited. In these situations, enhancement measures cannot be undertaken without consideration given to the introduction of food resources that will be readily available under present conditions. 89 refs., 7 figs., 11 tabs.« less

Early-life conditions and health at older ages: The mediating role of educational attainment, family and employment trajectories

PubMed Central

2018-01-01

Objectives We examine to what extent the effect of early-life conditions (health and socioeconomic status) on health in later life is mediated by educational attainment and life-course trajectories (fertility, partnership, employment). Methods Using data from the Survey of Health, Ageing and Retirement in Europe (N = 12,034), we apply, separately by gender, multichannel sequence analysis and cluster analysis to obtain groups of similar family and employment histories. The KHB method is used to disentangle direct and indirect effects of early-life conditions on health. Results Early-life-conditions indirectly impact on health in later life as result of their influence on education and family and employment trajectories. For example, between 22% and 42% of the effect of low parental socio-economic status at childhood on the three considered health outcomes at older age is explained by educational attainment for women. Even higher percentages are found for men (35% - 57%). On the contrary, the positive effect of poor health at childhood on poor health at older ages is not significantly mediated by education and life-course trajectories. Education captures most of the mediating effect of parental socio-economic status. More specifically, between 66% and 75% of the indirect effect of low parental socio-economic status at childhood on the three considered health outcomes at older age is explained by educational attainment for women. Again, higher percentages are found for men (86% - 93%). Early-life conditions, especially socioeconomic status, influence family and employment trajectories indirectly through their impact on education. We also find a persistent direct impact of early-life conditions on health at older ages. Conclusions Our findings demonstrate that early-life experiences influence education and life-course trajectories and health in later life, suggesting that public investments in children are expected to produce long lasting effects on people’s lives

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…

Seedling architechture and life history evolution in pines

Treesearch

Steven H. Strauss; F. Thomas Ledig

1985-01-01

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

Early Life Stress Affects Mortality Rate More than Social Behavior, Gene Expression or Oxidative Damage in Honey Bee Workers

PubMed Central

Rueppell, Olav; Yousefi, Babak; Collazo, Juan; Smith, Daniel

2017-01-01

Early life stressors can affect aging and life expectancy in positive or negative ways. Individuals can adjust their behavior and molecular physiology based on early life experiences but relatively few studies have connected such mechanisms to demographic patterns in social organisms. Sociality buffers individuals from environmental influences and it is unclear how much early life stress affects later life history. Workers of the honey bee (Apis mellifera L.) were exposed to two stressors, Varroa parasitism and paraquat exposure, early in life. Consequences were measured at the molecular, behavioral, and demographic level. While treatments did not significantly affect levels of oxidative damage, expression of select genes, and titers of the common deformed wing virus, most of these measures were affected by age. Some of the age effects, such as declining levels of deformed wing virus and oxidative damage, were opposite to our predictions but may be explained by demographic selection. Further analyses suggested some influences of worker behavior on mortality and indicated weak treatment effects on behavior. The latter effects were inconsistent among the two experiments. However, mortality rate was consistently reduced by Varroa mite stress during development. Thus, mortality was more responsive to early life stress than our other response variables. The lack of treatment effects on these measures may be due to the social organization of honey bees that buffers the individual from the impact of stressful developmental conditions. PMID:28122251

Early life stress affects mortality rate more than social behavior, gene expression or oxidative damage in honey bee workers.

PubMed

Rueppell, Olav; Yousefi, Babak; Collazo, Juan; Smith, Daniel

2017-04-01

Early life stressors can affect aging and life expectancy in positive or negative ways. Individuals can adjust their behavior and molecular physiology based on early life experiences but relatively few studies have connected such mechanisms to demographic patterns in social organisms. Sociality buffers individuals from environmental influences and it is unclear how much early life stress affects later life history. Workers of the honey bee (Apis mellifera L.) were exposed to two stressors, Varroa parasitism and Paraquat exposure, early in life. Consequences were measured at the molecular, behavioral, and demographic level. While treatments did not significantly affect levels of oxidative damage, expression of select genes, and titers of the common deformed wing virus, most of these measures were affected by age. Some of the age effects, such as declining levels of deformed wing virus and oxidative damage, were opposite to our predictions but may be explained by demographic selection. Further analyses suggested some influences of worker behavior on mortality and indicated weak treatment effects on behavior. The latter effects were inconsistent among the two experiments. However, mortality rate was consistently reduced by Varroa mite stress during development. Thus, mortality was more responsive to early life stress than our other response variables. The lack of treatment effects on these measures may be due to the social organization of honey bees that buffers the individual from the impact of stressful developmental conditions. Copyright © 2017 Elsevier Inc. All rights reserved.

Melanin-specific life-history strategies.

PubMed

Emaresi, Guillaume; Bize, Pierre; Altwegg, Res; Henry, Isabelle; van den Brink, Valentijn; Gasparini, Julien; Roulin, Alexandre

2014-02-01

The maintenance of genetic variation is a long-standing issue because the adaptive value of life-history strategies associated with each genetic variant is usually unknown. However, evidence for the coexistence of alternative evolutionary fixed strategies at the population level remains scarce. Because in the tawny owl (Strix aluco) heritable melanin-based coloration shows different physiological and behavioral norms of reaction, we investigated whether coloration is associated with investment in maintenance and reproduction. Light melanic owls had lower adult survival compared to dark melanic conspecifics, and color variation was related to the trade-off between offspring number and quality. When we experimentally enlarged brood size, light melanic males produced more fledglings but in poorer condition, and they were less often recruited in the local breeding population than those of darker melanic conspecifics. Our results also suggest that dark melanic males allocate a constant effort to raise their brood independently of environmental conditions, whereas lighter melanic males finely adjust reproductive effort in relation to changes in environmental conditions. Color traits can therefore be associated with life-history strategies, and stochastic environmental perturbation can temporarily favor one phenotype over others. The existence of fixed strategies implies that some phenotypes can sometimes display a "maladapted" strategy. Long-term population monitoring is therefore vital for a full understanding of how different genotypes deal with trade-offs.

Increased Pre- and Early-Adolescent Stress in Youth with a Family History of Substance Use Disorder and Early Substance Use Initiation.

PubMed

Charles, Nora E; Mathias, Charles W; Acheson, Ashley; Bray, Bethany C; Ryan, Stacy R; Lake, Sarah L; Liang, Yuanyuan; Dougherty, Donald M

2015-10-01

Individuals with a family history of substance use disorders (Family History Positive) are more likely to have early-onset substance use (i.e., prior to age 15), which may contribute to their higher rates of substance use disorders. One factor that may differentiate Family History Positive youth who engage in early-onset substance use from other Family History Positive youth is exposure to stressors. The aim of this study was to quantify how exposure to stressors from age 11-15 varies as a function of family history of substance use disorders and early-onset substance use. Self-reported stressors were prospectively compared in a sample of predominately (78.9%) Hispanic youth that included 68 Family History Positive youth (50% female) who initiated substance use by age 15 and demographically matched non-users with (n = 136; 52.9% female) and without (n = 75; 54.7% female) family histories of substance use disorders. Stressors were assessed at 6-month intervals for up to 4 years. Both the severity of stressors and the degree to which stressors were caused by an individual's own behavior were evaluated. All three groups differed from one another in overall exposure to stressors and rates of increase in stressors over time, with Family History Positive youth who engaged in early-onset substance use reporting the greatest exposure to stressors. Group differences were more pronounced for stressors caused by the participants' behavior. Family History Positive users had higher cumulative severity of stressors of this type, both overall and across time. These results indicate greater exposure to stressors among Family History Positive youth with early-onset substance use, and suggest that higher rates of behavior-dependent stressors may be particularly related to early-onset use.

Increased Pre- and Early-Adolescent Stress in Youth with a Family History of Substance Use Disorder and Early Substance Use Initiation

PubMed Central

Charles, Nora E.; Mathias, Charles W.; Acheson, Ashley; Bray, Bethany C.; Ryan, Stacy R.; Lake, Sarah L.; Liang, Yuanyuan; Dougherty, Donald M.

2015-01-01

Individuals with a family history of substance use disorders (Family History Positive) are more likely to have early-onset substance use (i.e., prior to age 15), which may contribute to their higher rates of substance use disorders. One factor that may differentiate Family History Positive youth who engage in early-onset substance use from other Family History Positive youth is exposure to stressors. The aim of this study was to quantify how exposure to stressors from age 11 to 15 varies as a function of family history of substance use disorders and early-onset substance use. Self-reported stressors were prospectively compared in a sample of predominately (78.9%) Hispanic youth that included 68 Family History Positive youth (50% female) who initiated substance use by age 15 and demographically matched non-users with (n=136; 52.9% female) and without (n=75; 54.7% female) family histories of substance use disorders. Stressors were assessed at 6-month intervals for up to 4 years. Both the severity of stressors and the degree to which stressors were caused by an individual’s own behavior were evaluated. All three groups differed from one another in overall exposure to stressors and rates of increase in stressors over time, with Family History Positive youth who engaged in early-onset substance use reporting the greatest exposure to stressors. Group differences were more pronounced for stressors caused by the participants’ behavior. Family History Positive users had higher cumulative severity of stressors of this type, both overall and across time. These results indicate greater exposure to stressors among Family History Positive youth with early-onset substance use, and suggest that higher rates of behavior-dependent stressors may be particularly related to early-onset use. PMID:25788123

Early-Life Socioeconomic Status and Adult Physiological Functioning: A Life Course Examination of Biosocial Mechanisms.

PubMed

Yang, Yang Claire; Gerken, Karen; Schorpp, Kristen; Boen, Courtney; Harris, Kathleen Mullan

2017-01-01

A growing literature has demonstrated a link between early-life socioeconomic conditions and adult health at a singular point in life. No research exists, however, that specifies the life course patterns of socioeconomic status (SES) in relation to the underlying biological processes that determine health. Using an innovative life course research design consisting of four nationally representative longitudinal datasets that collectively cover the human life span from early adolescence to old age (Add Health, MIDUS, NSHAP, and HRS), we address this scientific gap and assess how SES pathways from childhood into adulthood are associated with biophysiological outcomes in different adult life stages. For each dataset, we constructed standardized composite measures of early-life SES and adult SES and harmonized biophysiological measurements of immune and metabolic functioning. We found that the relative importance of early-life SES and adult SES varied across young, mid, and late adulthood, such that early-life SES sets a life course trajectory of socioeconomic well-being and operates through adult SES to influence health as adults age. We also documented evidence of the detrimental health effects of downward mobility and persistent socioeconomic disadvantage. These findings are the first to specify the life course patterns of SES that matter for underlying biophysiological functioning in different stages of adulthood. The study thus contributes new knowledge critical for improving population health by identifying the particular points in the life course at which interventions might be most effective in preventing disease and premature mortality.

Genetic tools link long-term demographic and life-history traits of anemonefish to their anemone hosts

NASA Astrophysics Data System (ADS)

Salles, Océane C.; Saenz-Agudelo, Pablo; Almany, Glenn R.; Berumen, Michael L.; Thorrold, Simon R.; Jones, Geoffrey P.; Planes, Serge

2016-12-01

The life-history traits and population dynamics of species are increasingly being attributed to the characteristics of their preferred habitats. While coral reef fish are often strongly associated with particular habitats, long-term studies establishing the demographic and life-history consequences of occupying different reef substrata are rare and no studies have monitored individuals in situ over their lifetime and determined the fate of their offspring. Here, we documented a quasi-turnover and local reproductive success for an entire population of orange clownfish ( Amphiprion percula) from Kimbe Island, Papua New Guinea, by taking bi-annual samples of DNA over a 10-yr period (2003-2013). We compared demographic and life-history traits of individuals living on two host anemone species, Heteractis magnifica and Stichodactyla gigantea, including female size, adult continued presence (a proxy for relative longevity range), early post-settlement growth, the number of eggs per clutch and `local' reproductive success (defined for each adult as the number of offspring returning to the natal population). Our results indicate that while the relative longevity of adults was similar on both host anemone species, females living in H. magnifica were larger than females in S. gigantea. However, despite females growing larger and producing more eggs on H. magnifica, we found that local reproductive success was significantly higher for clownfish living in S. gigantea. Life-history traits also exhibited local spatial variation, with higher local reproductive success recorded for adults living on S. gigantea on the eastern side of the island. Our findings support a `silver-spoon' hypothesis that predicts individuals that are fortunate enough to recruit into good habitat and location will be rewarded with higher long-term reproductive success and will make a disproportionate contribution to population renewal.

What shall I do now? State-dependent variations of life-history traits with aging in Wandering Albatrosses.

PubMed

Pardo, Deborah; Barbraud, Christophe; Weimerskirch, Henri

2014-02-01

Allocation decisions depend on an organism's condition which can change with age. Two opposite changes in life-history traits are predicted in the presence of senescence: either an increase in breeding performance in late age associated with terminal investment or a decrease due to either life-history trade-offs between current breeding and future survival or decreased efficiency at old age. Age variation in several life-history traits has been detected in a number of species, and demographic performances of individuals in a given year are influenced by their reproductive state the previous year. Few studies have, however, examined state-dependent variation in life-history traits with aging, and they focused mainly on a dichotomy of successful versus failed breeding and non-breeding birds. Using a 50-year dataset on the long-lived quasi-biennial breeding wandering albatross, we investigated variations in life-history traits with aging according to a gradient of states corresponding to potential costs of reproduction the previous year (in ascending order): non-breeding birds staying at sea or present at breeding grounds, breeding birds that failed early, late or were successful. We used multistate models to study survival and decompose reproduction into four components (probabilities of return, breeding, hatching, and fledging), while accounting for imperfect detection. Our results suggest the possible existence of two strategies in the population: strict biennial breeders that exhibited almost no reproductive senescence and quasi-biennial breeders that showed an increased breeding frequency with a strong and moderate senescence on hatching and fledging probabilities, respectively. The patterns observed on survival were contrary to our predictions, suggesting an influence of individual quality rather than trade-offs between reproduction and survival at late ages. This work represents a step further into understanding the evolutionary ecology of senescence and its

Person to Person: A Collection of Life History Stories.

ERIC Educational Resources Information Center

Fraenkel, Brenda; Hadfield, Sara

1988-01-01

An oral history project paired deaf high school students with deaf senior citizens for five meetings over a two-month period. The students then wrote up life history stories. The experience gave students experience in interviewing skills, notetaking, and writing as well as developing friendships and increased understanding of deaf older people.…

An organismal concept for Sengelia radicans gen. et sp. nov. – morphology and natural history of an Early Devonian lycophyte

PubMed Central

Tomescu, Alexandru M. F.

2017-01-01

Abstract Background and Aims Fossil plants are found as fragmentary remains and understanding them as natural species requires assembly of whole-organism concepts that integrate different plant parts. Such concepts are essential for incorporating fossils in hypotheses of plant evolution and phylogeny. Plants of the Early Devonian are crucial to reconstructing the initial radiation of tracheophytes, yet few are understood as whole organisms. Methods This study assembles a whole-plant concept for the Early Devonian lycophyte Sengelia radicans gen. et sp. nov., based on morphometric data and taphonomic observations from >1000 specimens collected in the Beartooth Butte Formation (Wyoming, USA). Key Results Sengelia radicans occupies a key position between stem-group and derived lycophyte lineages. Sengelia had a rooting system of downward-growing root-bearing stems, formed dense monotypic mats of prostrate shoots in areas that experienced periodic flooding, and was characterized by a life-history strategy adapted for survival after floods, dominated by clonality, and featuring infrequent sexual reproduction. Conclusions Sengelia radicans is the oldest among the very few early tracheophytes for which a detailed, rigorous whole-plant concept integrates morphology, growth habit, life history and growth environment. This plant adds to the diversity of body plans documented among lycophytes and may help elucidate patterns of morphological evolution in the clade. PMID:28334100

Early Childhood Education: History, Theory, and Practice. Second Edition

ERIC Educational Resources Information Center

Morgan, Harry

2010-01-01

Harry Morgan lays the foundations of what early childhood education is by integrating the history of the field with the philosophy and theories behind this discipline. From birth to age eight, when children become integrated into society through their education at school and at home, "Early Childhood Education" examines the education of this age…

Do pioneers have r-selected traits? Life history patterns among colonizing terrestrial gastropods.

PubMed

Bengtsson, J; Baur, B

1993-05-01

We examine whether pioneer species of terrestrial gastropods (snails and slugs) possess particular life history traits commonly associated with r-selection, using data on gastropod colonization in four areas in north-west Europe (the Kvarken and Tvärminne archipelagos in the Baltic, polder woods in IJsselmeer, and a rehabilitated quarry near Maastricht). Data on age at first reproduction, longevity, clutch size, egg size and lifetime fecundity were gathered from the literature. In order to control for potentially confounding effects of body size on life history traits, we compared the residuals from the allometric relations between life history traits and body size for pioneers and non-pioneers. In snails, all life history traits examined were related to body size. In slugs, all traits except age at first reproduction scaled with body size. Body sizes did not differ between pioneers and non-pioneers in any area. In all four areas, there were no significant differences between pioneers and non-pioneers in any of the life history traits examined, after body size had been taken into account. This indicates that pioneer terrestrial gastropods generally cannot be regarded as r-selected. Pioneer species may possess any of several life history strategies, and the combinations of traits shown by them may have little in common with the r-K selection concept.

Litter sex composition affects life-history traits in yellow-bellied marmots.

PubMed

Monclús, Raquel; Blumstein, Daniel T

2012-01-01

1. The presence of siblings might have long-lasting fitness consequences because they influence the early environment in which an animal develops. Several studies under laboratory conditions have shown long-lasting consequences from the presence of male siblings in utero on morphology and life-history traits. However, in wild animals, such effects of litter sex composition are unexplored. 2. We capitalized on a long-term study of individually marked yellow-bellied marmots (Marmota flaviventris) and documented the effects of weaned litter sex composition and anogenital distance on several life-history and fitness traits. 3. First, we demonstrated that the number of males in a litter influenced anogenital distance. Then, we found that masculinized females, those with larger anogenital distances, were less likely to survive their first hibernation, were more likely to disperse and were less likely to become pregnant and wean young. Males from male-biased litters had lower growth rates, but we failed to detect longer-term consequences. 4. Taken together, our results show profound sex-dependent effects of litter sex composition, probably due to differential prenatal exposure to androgens, in free-living animals. We conclude that masculinization might constitute an alternative mechanism explaining variation in different demographic traits. This finding highlights the importance of studying these maternal effects, and they enhance our concern over the widespread use of endocrine disrupting compounds. © 2011 The Authors. Journal of Animal Ecology © 2011 British Ecological Society.

Reevaluating geographic variation in life-history traits of a widespread Nearctic amphibian

USGS Publications Warehouse

Davenport, Jon M.; Hossack, Blake R.

2016-01-01

Animals from cold environments are usually larger than animals from warm environments, which often produce clines in body size. Because variation in body size can lead to trade-offs between growth and reproduction, life-history traits should also vary across climatic gradients. To determine if life-history traits of wood frogs Rana sylvatica vary with climate, we examined female and male body length, clutch size, and ovum size from 37 locations across an unprecedented 32° of latitude. In conflict with recent research, body size, and ovum size decreased in cold climates and at higher latitudes. Clutch size did not vary with climate or latitude, but reproductive effort (clutch size:female size) did, suggesting selection for a life-history traits that favors maximizing propagule number over propagule size in cold climates. With accelerating climate change that will expose populations to novel environmental conditions, it is important to identify the limits of adaptation, which can be informed by greater understanding of variation in life-history traits.

Transcriptomic and macroevolutionary evidence for phenotypic uncoupling between frog life history phases

PubMed Central

Wollenberg Valero, Katharina C.; Garcia-Porta, Joan; Rodríguez, Ariel; Arias, Mónica; Shah, Abhijeet; Randrianiaina, Roger Daniel; Brown, Jason L.; Glaw, Frank; Amat, Felix; Künzel, Sven; Metzler, Dirk; Isokpehi, Raphael D.; Vences, Miguel

2017-01-01

Anuran amphibians undergo major morphological transitions during development, but the contribution of their markedly different life-history phases to macroevolution has rarely been analysed. Here we generate testable predictions for coupling versus uncoupling of phenotypic evolution of tadpole and adult life-history phases, and for the underlying expression of genes related to morphological feature formation. We test these predictions by combining evidence from gene expression in two distantly related frogs, Xenopus laevis and Mantidactylus betsileanus, with patterns of morphological evolution in the entire radiation of Madagascan mantellid frogs. Genes linked to morphological structure formation are expressed in a highly phase-specific pattern, suggesting uncoupling of phenotypic evolution across life-history phases. This gene expression pattern agrees with uncoupled rates of trait evolution among life-history phases in the mantellids, which we show to have undergone an adaptive radiation. Our results validate a prevalence of uncoupling in the evolution of tadpole and adult phenotypes of frogs. PMID:28504275

Ocean warming has a greater effect than acidification on the early life history development and swimming performance of a large circumglobal pelagic fish.

PubMed

Watson, Sue-Ann; Allan, Bridie J M; McQueen, David E; Nicol, Simon; Parsons, Darren M; Pether, Stephen M J; Pope, Stephen; Setiawan, Alvin N; Smith, Neville; Wilson, Carly; Munday, Philip L

2018-05-22

Ocean warming and acidification are serious threats to marine life; however, their individual and combined effects on large pelagic and predatory fishes are poorly understood. We determined the effects of projected future temperature and carbon dioxide (CO 2 ) levels on survival, growth, morphological development and swimming performance on the early life stages of a large circumglobal pelagic fish, the yellowtail kingfish Seriola lalandi. Eggs, larvae and juveniles were reared in cross-factored treatments of temperature (21 and 25°C) and pCO 2 (500 and 985 μatm) from fertilisation to 25 days post hatching (dph). Temperature had the greatest effect on survival, growth and development. Survivorship was lower, but growth and morphological development were faster at 25°C, with surviving fish larger and more developed at 1, 11 and 21 dph. Elevated pCO 2 affected size at 1 dph, but not at 11 or 21 dph, and did not affect survival or morphological development. Elevated temperature and pCO 2 had opposing effects on swimming performance at 21 dph. Critical swimming speed (U crit ) was increased by elevated temperature but reduced by elevated pCO 2 . Additionally, elevated temperature increased the proportion of individuals that responded to a startle stimulus, reduced latency to respond and increased maximum escape speed, potentially due to the more advanced developmental stage of juveniles at 25°C. By contrast, elevated pCO 2 reduced the distance moved and average speed in response to a startle stimulus. Our results show that higher temperature is likely to be the primary driver of global change impacts on kingfish early life history; however, elevated pCO 2 could affect critical aspects of swimming performance in this pelagic species. Our findings will help parameterise and structure fisheries population dynamics models and improve projections of impacts to large pelagic fishes under climate change scenarios to better inform adaptation and mitigation responses

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

PubMed

Plastow, Nicola Ann

2006-01-01

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

Connecting proximate mechanisms and evolutionary patterns: pituitary gland size and mammalian life history.

PubMed

Kamilar, J M; Tecot, S R

2015-11-01

At the proximate level, hormones are known to play a critical role in influencing the life history of mammals, including humans. The pituitary gland is directly responsible for producing several hormones, including those related to growth and reproduction. Although we have a basic understanding of how hormones affect life history characteristics, we still have little knowledge of this relationship in an evolutionary context. We used data from 129 mammal species representing 14 orders to investigate the relationship between pituitary gland size and life history variation. Because pituitary gland size should be related to hormone production and action, we predicted that species with relatively large pituitaries should be associated with fast life histories, especially increased foetal and post-natal growth rates. Phylogenetic analyses revealed that total pituitary size and the size of the anterior lobe of the pituitary significantly predicted a life history axis that was correlated with several traits including body mass, and foetal and post-natal growth rates. Additional models directly examining the association between relative pituitary size and growth rates produced concordant results. We also found that relative pituitary size variation across mammals was best explained by an Ornstein-Uhlenbeck model of evolution, suggesting an important role of stabilizing selection. Our results support the idea that the size of the pituitary is linked to life history variation through evolutionary time. This pattern is likely due to mediating hormone levels but additional work is needed. We suggest that future investigations incorporating endocrine gland size may be critical for understanding life history evolution. © 2015 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2015 European Society For Evolutionary Biology.

Population density and climate shape early-life survival and recruitment in a long-lived pelagic seabird.

PubMed

Fay, Rémi; Weimerskirch, Henri; Delord, Karine; Barbraud, Christophe

2015-09-01

1. Our understanding of demographic processes is mainly based on analyses of traits from the adult component of populations. Early-life demographic traits are poorly known mainly for methodological reasons. Yet, survival of juvenile and immature individuals is critical for the recruitment into the population and thus for the whole population dynamic, especially for long-lived species. This bias currently restrains our ability to fully understand population dynamics of long-lived species and life-history theory. 2. The goal of this study was to estimate the early-life demographic parameters of a long-lived species with a long immature period (9-10 years), to test for sex and age effects on these parameters and to identify the environmental factors encountered during the period of immaturity that may influence survival and recruitment. 3. Using capture-mark-recapture multievent models allowing us to deal with uncertain and unobservable individual states, we analysed a long-term data set of wandering albatrosses to estimate both age- and sex-specific early-life survival and recruitment. We investigated environmental factors potentially driving these demographic traits using climatic and fisheries covariates and tested for density dependence. 4. Our study provides for the first time an estimate of annual survival during the first 2 years at sea for an albatross species (0·801 ± 0·014). Both age and sex affected early-life survival and recruitment processes of this long-lived seabird species. Early-life survival and recruitment were highly variable across years although the sensitivity of young birds to environmental variability decreased with age. Early-life survival was negatively associated with sea surface temperature, and recruitment rate was positively related to both Southern Annular Mode and sea surface temperature. We found strong evidence for density-dependent mortality of juveniles. Population size explained 41% of the variation of this parameter over the

The Littlest Historians: Early Years Programming in History Museums

ERIC Educational Resources Information Center

Leftwich, Mariruth; Haywood, Clare

2016-01-01

Working with children under five years old and the adults that accompany them is a rapidly growing area within the museum and wider cultural sector, with important emphasis being placed on early learning in both the United Kingdom and United States. For history museums in particular, early learning offers a unique set of questions and challenges,…

Early life stress predicts negative urgency through brooding, depending on 5-HTTLPR genotype: A pilot study with 6-month follow-up examining suicide ideation.

PubMed

Valderrama, Jorge; Miranda, Regina

2017-12-01

The present study examined the interaction between early life stress and 5-HTT genotypes in predicting two risk factors for suicidal behavior - the brooding subtype of rumination and impulsivity, in the form of negative urgency - over time. Furthermore, we examined early life stress, brooding, and impulsivity as predictors of suicidal ideation over time. Participants with and without a history of early life stress were genotyped for the 5-HTTLPR polymorphism and completed assessments assessing brooding and negative urgency at baseline and 6-month follow up. Early life emotional abuse was associated with negative urgency at follow-up. We found an indirect effect of early life emotional abuse on negative urgency through brooding among individuals with 5-HTT low expressing genotypes but not among individuals with 5-HTT high expressing genotypes. Further, a logistic regression analysis revealed that negative urgency was associated with higher odds (O.R. = 16.2) of reporting suicide ideation (versus no ideation) at follow-up. Our findings suggest that brooding and negative urgency may result from the interaction between early life emotional abuse and 5-HTT low expressing genotypes. Further research is necessary to understand how early life stress interacts with 5-HTT genotypes to confer risk for suicidal behavior through psychological mechanisms. Copyright © 2017 Elsevier B.V. All rights reserved.

The Early History of Psychoanalysis in San Francisco.

PubMed

Benveniste, Daniel

2006-01-01

The early history of psychoanalysis in San Francisco begins in 1918 and ends in 1953. During those 35 years the San Francisco Bay Area witnessed the awakening of interest in psychoanalysis, the arrival of the European émigré analysts and the emergence of individuals and groups engaging in extraordinarily creative work and doing so in an ecumenical spirit and with a social commitment. This article provides an overview of this illustrious history and the people who participated in it.

Generation time, life history and the substitution rate of neutral mutations.

PubMed

Lehtonen, Jussi; Lanfear, Robert

2014-11-01

Our understanding of molecular evolution is hampered by a lack of quantitative predictions about how life-history (LH) traits should correlate with substitution rates. Comparative studies have shown that neutral substitution rates vary substantially between species, and evidence shows that much of this diversity is associated with variation in LH traits. However, while these studies often agree, some unexplained and contradictory results have emerged. Explaining these results is difficult without a clear theoretical understanding of the problem. In this study, we derive predictions for the relationships between LH traits and substitution rates in iteroparous species by using demographic theory to relate commonly measured life-history traits to genetic generation time, and by implication to neutral substitution rates. This provides some surprisingly simple explanations for otherwise confusing patterns, such as the association between fecundity and substitution rates. The same framework can be applied to more complex life histories if full life-tables are available. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

Effects of early life factors on the health and quality of life of older adults.

PubMed

Yilmaz, Fikriye; N Tekin, Rukiye

2018-01-01

Few studies on the effects of early life factors on the health and quality of life of adults have been conducted in Turkey. We aimed to investigate the effects of early life factors on the health and quality of life of older adults. We administered a questionnaire to 350 adults, aged 50-89 years, living in Cankaya, Ankara. The questionnaire covered sociodemographic characteristics, early life characteristics, health status, and the World Health Organization Quality of Life-Ageing scale. Data were analyzed using χ 2 tests, independent samples t-tests, one-way anova, and binary logistic regression analysis. The analyses showed that the most important risk factors for chronic disease were being ≥65 years (odds ratio (OR) = 2.34), having a chronic health problem before 18 years of age (OR = 2.48), experiencing prolonged hospitalization or bed rest before 18 years of age (OR = 2.65), and experiencing parental unconcern during early life (OR = 2.13) (P < 0.05). In addition, having a high school education or less includes people who have primary or secondary or high school diploma (OR = 1.65), having lived in a village (OR = 1.65), having a low family economic status (OR = 2.40), and having experienced one negative event (OR = 1.41) or two or more negative events (OR = 1.39) during their early lives were identified as important risk factors for low quality of life (P < 0.05). Early life factors are among the important determinants of the health and quality of life of older adults in Turkey. © 2017 Japanese Psychogeriatric Society.

Early-Life Origins of the Race Gap in Men's Mortality

ERIC Educational Resources Information Center

Warner, David F.; Hayward, Mark D.

2006-01-01

Using a life course framework, we examine the early life origins of the race gap in men's all-cause mortality. Using the National Longitudinal Survey of Older Men (1966-1990), we evaluate major social pathways by which early life conditions differentiate the mortality experiences of blacks and whites. Our findings indicate that early life…

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…

Brief Self-Report Scales Assessing Life History Dimensions of Mating and Parenting Effort.

PubMed

Kruger, Daniel J

2017-01-01

Life history theory (LHT) is a powerful evolutionary framework for understanding physiological, psychological, and behavioral variation both between and within species. Researchers and theorists are increasingly integrating LHT into evolutionary psychology, as it provides a strong foundation for research across many topical areas. Human life history variation has been represented in psychological and behavioral research in several ways, including indicators of conditions in the developmental environment, indicators of conditions in the current environment, and indicators of maturation and life milestones (e.g., menarche, initial sexual activity, first pregnancy), and in self-report survey scale measures. Survey scale measures have included constructs such as time perspective and future discounting, although the most widely used index is a constellation of indicators assessing the K-factor, thought to index general life history speed (from fast to slow). The current project examined the utility of two brief self-report survey measures assessing the life history dimensions of mating effort and parenting effort with a large undergraduate sample in the United States. Consistent with the theory, items reflected two inversely related dimensions. In regressions including the K-factor, the Mating Effort Scale proved to be a powerful predictor of other constructs and indicators related to life history variation. The Parenting Effort Scale had less predictive power overall, although it explained unique variance across several constructs and was the only unique predictor of the number of long-term (serious and committed) relationships. These scales may be valuable additions to self-report survey research projects examining life history variation.

Music as therapy in early history.

PubMed

Thaut, Michael H

2015-01-01

The notion of music as therapy is based on ancient cross-cultural beliefs that music can have a "healing" effect on mind and body. Explanations for the therapeutic mechanisms in music have almost always included cultural and social science-based causalities about the uses and functions of music in society. However, it is also important to note that the view of music as "therapy" was also always strongly influenced by the view and understanding of the concepts and causes of disease. Magical/mystical concepts of illness and "rational" medicine probably lived side by side for thousands of years. Not until the late-nineteenth and early-twentieth centuries were the scientific foundations of medicine established, which allowed the foundations of music in therapy to progress from no science to soft science and most recently to actual brain science. Evidence for "early music therapy" will be discussed in four broad historical-cultural divisions: preliterate cultures; early civilizations in Mesopotamia, Egypt, Israel; Greek Antiquity; Middle Ages, Renaissance, and Baroque. In reviewing "early music therapy" practice, from mostly unknown periods of early history (using preliterate cultures as a window) to increasingly better documented times, including preserved notation samples of actual "healing" music, five theories and applications of early music therapy can be differentiated. © 2015 Elsevier B.V. All rights reserved.

Contemporary divergence in early life history in grayling (Thymallus thymallus).

PubMed

Thomassen, Gaute; Barson, Nicola J; Haugen, Thrond O; Vøllestad, L Asbjørn

2011-12-13

Following colonization of new habitats and subsequent selection, adaptation to environmental conditions might be expected to be rapid. In a mountain lake in Norway, Lesjaskogsvatnet, more than 20 distinct spawning demes of grayling have been established since the lake was colonized, some 20-25 generations ago. The demes spawn in tributaries consistently exhibiting either colder or warmer temperature conditions during spawning in spring and subsequent early development during early summer. In order to explore the degree of temperature-related divergence in early development, a multi-temperature common-garden experiment was performed on embryos from four different demes experiencing different spring temperatures. Early developmental characters were measured to test if individuals from the four demes respond differently to the treatment temperatures. There was clear evidence of among-deme differences (genotype - environment interactions) in larval growth and yolk-to-body-size conversion efficiency. Under the cold treatment regime, larval growth rates were highest for individuals belonging to cold streams. Individuals from warm streams had the highest yolk-consumption rate under cold conditions. As a consequence, yolk-to-body-mass conversion efficiency was highest for cold-deme individuals under cold conditions. As we observed response parallelism between individuals from demes belonging to similar thermal groups for these traits, some of the differentiation seems likely to result from local adaptation The observed differences in length at age during early larval development most likely have a genetic component, even though both directional and random processes are likely to have influenced evolutionary change in the demes under study.

Ecological volatility and human evolution: a novel perspective on life history and reproductive strategy.

PubMed

Wells, Jonathan C K

2012-11-01

Humans are characterized by a suite of traits that seem to differentiate them profoundly from closely related apes such as the gorilla, chimpanzee, and orang-utan. These traits include longevity, cooperative breeding, stacking of offspring, lengthy maturation, and a complex life-course profile of adiposity. When, how, and why these traits emerged during our evolutionary history is currently attracting considerable attention. Most approaches to life history emphasize dietary energy availability and the risk of mortality as the two key stresses shaping life-history variability between and within species. The high energy costs of the large Homo brain are also seen as the central axis around which other life-history traits were reorganized. I propose that ecological volatility may have been a key stress, selecting in favor of the suite of traits in order to tolerate periods of energy scarcity, and increase reproductive output during periods of good conditions. Theses life-history adaptations may have preceded and enabled the trend toward encephalization. Copyright © 2012 Wiley Periodicals, Inc.

Predicting responses to climate change requires all life-history stages.

PubMed

Zeigler, Sara

2013-01-01

In Focus: Radchuk, V., Turlure, C. & Schtickzelle, N. (2013) Each life stage matters: the importance of assessing response to climate change over the complete life cycle in butterflies. Journal of Animal Ecology, 82, 275-285. Population-level responses to climate change depend on many factors, including unexpected interactions among life history attributes; however, few studies examine climate change impacts over complete life cycles of focal species. Radchuk, Turlure & Schtickzelle () used experimental and modelling approaches to predict population dynamics for the bog fritillary butterfly under warming scenarios. Although they found that warming improved fertility and survival of all stages with one exception, populations were predicted to decline because overwintering larvae, whose survival declined with warming, were disproportionately important contributors to population growth. This underscores the importance of considering all life history stages in analyses of climate change's effects on population dynamics. © 2012 The Authors. Journal of Animal Ecology © 2012 British Ecological Society.

Mineral remains of early life on Earth? On Mars?

USGS Publications Warehouse

Iberall, Robbins E.; Iberall, A.S.

1991-01-01

The oldest sedimentary rocks on Earth, the 3.8-Ga Isua Iron-Formation in southwestern Greenland, are metamorphosed past the point where organic-walled fossils would remain. Acid residues and thin sections of these rocks reveal ferric microstructures that have filamentous, hollow rod, and spherical shapes not characteristic of crystalline minerals. Instead, they resemble ferric-coated remains of bacteria. Because there are no earlier sedimentary rocks to study on Earth, it may be necessary to expand the search elsewhere in the solar system for clues to any biotic precursors or other types of early life. A study of morphologies of iron oxide minerals collected in the southern highlands during a Mars sample return mission may therefore help to fill in important gaps in the history of Earth's earliest biosphere. -from Authors

Material security, life history, and moralistic religions: A cross-cultural examination

PubMed Central

Ross, Cody T.; Apicella, Coren; Atkinson, Quentin D.; Cohen, Emma; McNamara, Rita Anne; Willard, Aiyana K.; Xygalatas, Dimitris; Norenzayan, Ara; Henrich, Joseph

2018-01-01

Researchers have recently proposed that “moralistic” religions—those with moral doctrines, moralistic supernatural punishment, and lower emphasis on ritual—emerged as an effect of greater wealth and material security. One interpretation appeals to life history theory, predicting that individuals with “slow life history” strategies will be more attracted to moralistic traditions as a means to judge those with “fast life history” strategies. As we had reservations about the validity of this application of life history theory, we tested these predictions with a data set consisting of 592 individuals from eight diverse societies. Our sample includes individuals from a wide range of traditions, including world religions such as Buddhism, Hinduism and Christianity, but also local traditions rooted in beliefs in animism, ancestor worship, and worship of spirits associated with nature. We first test for the presence of associations between material security, years of formal education, and reproductive success. Consistent with popular life history predictions, we find evidence that material security and education are associated with reduced reproduction. Building on this, we then test whether or not these demographic factors predict the moral concern, punitiveness, attributed knowledge-breadth, and frequency of ritual devotions towards two deities in each society. Here, we find no reliable evidence of a relationship between number of children, material security, or formal education and the individual-level religious beliefs and behaviors. We conclude with a discussion of why life-history theory is an inadequate interpretation for the emergence of factors typifying the moralistic traditions. PMID:29513766

Asperger syndrome and "non-verbal learning problems" in a longitudinal perspective: neuropsychological and social adaptive outcome in early adult life.

PubMed

Hagberg, Bibbi S; Nydén, Agneta; Cederlund, Mats; Gillberg, Christopher

2013-12-15

Co-existence of Asperger syndrome (AS) and non-verbal learning disability (NLD) has been proposed based on the observation that people with AS tend to have significantly higher verbal than performance IQ (VIQ > PIQ by ≥ 15 points), one of the core features of NLD. In the present study we examined neuropsychological and social adaptive profiles with "non-verbal learning problems" associated with NLD in a group of individuals with AS followed from childhood into early adult life. The group was divided into three subgroups: (i) persistent NLD (P-NLD), i.e. NLD (VIQ > PIQ) both in childhood and early adulthood occasions, (ii) childhood NLD (CO-NLD), i.e. NLD (VIQ > PIQ) only at original diagnosis, or (iii) No NLD (VIQ > PIQ) ever (NO-NLD). All three subgroups were followed prospectively from childhood into adolescence and young adult life. One in four to one in five of the whole group of males with AS had P-NLD. The P-NLD subgroup had poorer neuropsychological outcome in early adult life than did those with CO-NLD and those with NO-NLD. There were no unequivocal markers in early childhood that predicted subgroup status in early adult life, but early motor delay and a history of early speech-language problems tended to be associated with P-NLD. © 2013 Elsevier Ireland Ltd. All rights reserved.

Gender, sexuality and the participatory dimensions of a comparative life history policy study.

PubMed

Macdonnell, Judith A

2011-12-01

Gender, sexuality and the participatory dimensions of a comparative life history policy study In this paper, I explore how a critical feminist lens was a crucial element in creating a participatory policy study which used a qualitative design and comparative life history methodology. This study focused on Canadian nurses' political practice related to advocacy for lesbian health. Findings show that the combination of the gender lens and life history approach offers potential to create knowledge in ways aligned with health-promoting and emancipatory outcomes. However, the nature of participation and interaction by researcher and participants is contexualized and contested given complex dynamics of power that shape all aspects of this doctoral study process. The critical feminist lens with its focus on reflexivity informed the content and process of knowledge production in this study and shaped key turning points: the ways in which this policy study was conceptualized, the choice of comparative life history methodology, ethical considerations, data collection and analysis and representation of findings. Life history is unlikely to be the methodology that first comes to mind when undertaking a policy study. Its historical roots are associated with biographical, oral history and narrative approaches, which typically aim to elicit understanding of lived experience. Yet, it was this very aspect, this focus on lived experience, which rendered life history methodology fitting as I contemplated how to examine the relationship between nurses and policy. I was interested in understanding nurses' political practice, how policy influenced nurses' capacity to advocate in their everyday lives, as well as nurses' impacts on policy processes and their larger social worlds. © 2011 Blackwell Publishing Ltd.

Carryover effects of predation risk on postembryonic life-history stages in a freshwater shrimp.

PubMed

Ituarte, Romina Belén; Vázquez, María Guadalupe; González-Sagrario, María de los Ángeles; Spivak, Eduardo Daniel

2014-04-01

For organisms with complex life histories it is well known that risk experienced early in life, as embryos or larvae, may have effects throughout the life cycle. Although carryover effects have been well documented in invertebrates with different levels of parental care, there are few examples of predator-induced responses in externally brooded embryos. Here, we studied the effects of nonlethal predation risk throughout the embryonic development of newly spawned eggs carried by female shrimp on the timing of egg hatching, hatchling morphology, larval development and juvenile morphology. We also determined maternal body mass at the end of the embryonic period. Exposure to predation risk cues during embryonic development led to larger larvae which also had longer rostra but reached the juvenile stage sooner, at a smaller size and with shorter rostra. There was no difference in hatching timing, but changes in larval morphology and developmental timing showed that the embryos had perceived waterborne substances indicative of predation risk. In addition to carryover effects on larval and juvenile stages, predation threat provoked a decrease of body mass in mothers exposed to predator cues while brooding. Our results suggest that risk-exposed embryos were able to recognize the same infochemicals as their mothers, manifesting a response in the free-living larval stage. Thus, future studies assessing anti-predator phenotypes should include embryonic development, which seems to determine the morphology and developmental time of subsequent life-history stages according to perceived environmental conditions. Copyright © 2014 Elsevier GmbH. All rights reserved.

BRIDGING SCALES IN THE EVOLUTION OF INFECTIOUS DISEASE LIFE HISTORIES: APPLICATION

PubMed Central

Mideo, Nicole; Nelson, William A.; Reece, Sarah E.; Bell, Andrew S.; Read, Andrew F.; Day, Troy

2014-01-01

Within- and between-host disease processes occur on the same timescales, therefore changes in the within-host dynamics of parasites, resources, and immunity can interact with changes in the epidemiological dynamics to affect evolutionary outcomes. Consequently, studies of the evolution of disease life histories, that is, infection-age-specific patterns of transmission and virulence, have been constrained by the need for a mechanistic understanding of within-host disease dynamics. In a companion paper (Day et al. 2011), we develop a novel approach that quantifies the relevant within-host aspects of disease through genetic covariance functions. Here, we demonstrate how to apply this theory to data. Using two previously published datasets from rodent malaria infections, we show how to translate experimental measures into disease life-history traits, and how to quantify the covariance in these traits. Our results show how patterns of covariance can interact with epidemiological dynamics to affect evolutionary predictions for disease life history. We also find that the selective constraints on disease life-history evolution can vary qualitatively, and that “simple” virulence-transmission trade-offs that are often the subject of experimental investigation can be obscured by trade-offs within one trait alone. Finally, we highlight the type and quality of data required for future applications. PMID:22023593

Masked expression of life-history traits in a highly variable environment

USGS Publications Warehouse

DeBoer, Jason A.; Fontaine, Joseph J.; Chizinski, Christopher J.; Pope, Kevin L.

2015-01-01

Differing life-history strategies may act as a constraint on reproductive expression that ultimately limits the ability of individual species to respond to changes in the magnitude or frequency of environmental variation, and potentially underlies the variation often inherent in phenotypic and evolved responses to anthropogenic change. Alternatively, if there are environmental cues that predict reproductive potential, differential expression of life-history strategies may represent differences in the adaptive capacity to optimize current reproductive value given variation in environmental conditions. We compared several aspects of walleye Sander vitreus spawning ecology at two reservoirs that differ in environmental variability (i.e., annual water-level fluctuation) to identify the capacity of phenotypic expression and the corresponding association with age. Despite significant differences in female body and liver masses between reservoirs that differ in environmental variability, we found no difference in reproductive investment measured by egg size and fecundity. Walleye in a highly variable environment appear to exhibit reproductive traits more typical of a short-lived life-history strategy, which may be resultant from the interaction of environmental and anthropogenic pressures. This finding emphasizes the need to identify the degree to which life-history expression represents physiological constraints versus ecological optimization, particularly as anthropogenic change continues to alter environmental conditions. 

An assessment of oil spill effects on pink salmon populations following the Exxon Valdez oil spill. Part 1: Early life history

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brannon, E.L.; Moulton, L.L.; Gilbertson, L.G.

1995-12-31

This paper discusses results of field programs initiated within a few days of the spill and designed to assess spill effects on critical early life stages of pink salmon in postspill years. Samples of water and stream sediments from throughout the spill area were used to define the exposure of pink salmon to residual hydrocarbons from the spill. Mean sediment concentrations of polycyclic aromatic hydrocarbons (PAH) up to 300 ppb were measured in oiled streams in 1989 and generally followed a downward trend toward background in 1990 and 1991. These PAH concentrations were then used in regression analyses of potentialmore » effects on key early life stages of pink salmon. Water samples taken from both nearshore feeding and rearing areas and offshore migratory areas show that hydrocarbon concentrations were from one to four orders of magnitude lower than concentrations reported in the literature to cause acute or chronic effects on fish species. The postspill field and laboratory studies of pink salmon early life stages included examination of potential effects on 1989, 1990, and 1991 eggs, fry, and juveniles. 28 refs., 8 figs., 8 tabs.« less

Disturbance, life history traits, and dynamics in an old-growth forest landscape of southeastern Europe.

PubMed

Nagel, Thomas A; Svoboda, Miroslav; Kobal, Milan

2014-06-01

Much of our understanding of natural forest dynamics in the temperate region of Europe is based on observational studies in old-growth remnants that have emphasized small-scale gap dynamics and equilibrium stand structure and composition. Relatively little attention has been given to the role of infrequent disturbance events in forest dynamics. In this study, we analyzed dendroecological data from four stands and three windthrow patches in an old-growth landscape in the Dinaric Mountains of Bosnia and Herzegovina to examine disturbance history, tree life history traits, and compositional dynamics. Over all stands, most decades during the past 340 years experienced less than 10% canopy loss, yet each stand showed evidence of periodic intermediate-severity disturbances that removed > 40% of the canopy, some of which were synchronized over the study area landscape. Analysis of radial growth patterns indicated several life history differences among the dominant canopy trees; beech was markedly older than fir, while growth patterns of dead and dying trees suggested that fir was able to tolerate longer periods of suppressed growth in shade. Maple had the fastest radial growth and accessed the canopy primarily through rapid early growth in canopy gaps, whereas most beech and fir experienced a period of suppressed growth prior to canopy accession. Peaks in disturbance were roughly linked to increased recruitment, but mainly of shade-tolerant beech and fir; less tolerant species (i.e., maple, ash, and elm) recruited successfully on some of the windthown sites where advance regeneration of beech and fir was less abundant. The results challenge the traditional notions of stability in temperate old-growth forests of Europe and highlight the nonequilibrial nature of canopy composition due to unique histories of disturbance and tree life history differences. These findings provide valuable information for developing natural disturbance-based silvicultural systems, as well as

Does encephalization correlate with life history or metabolic rate in Carnivora?

PubMed

Finarelli, John A

2010-06-23

A recent analysis of brain size evolution reconstructed the plesiomorphic brain-body size allometry for the mammalian order Carnivora, providing an important reference frame for comparative analyses of encephalization (brain volume scaled to body mass). I performed phylogenetically corrected regressions to remove the effects of body mass, calculating correlations between residual values of encephalization with basal metabolic rate (BMR) and six life-history variables (gestation time, neonatal mass, weaning time, weaning mass, litter size, litters per year). No significant correlations were recovered between encephalization and any life-history variable or BMR, arguing against hypotheses relating encephalization to maternal energetic investment. However, after correcting for clade-specific adaptations, I recovered significant correlations for several variables, and further analysis revealed a conserved carnivoran reproductive strategy, linking degree of encephalization to the well-documented mammalian life-history trade-off between neonatal mass and litter size. This strategy of fewer, larger offspring correlating with increased encephalization remains intact even after independent changes in encephalization allometries in the evolutionary history of this clade.

Does encephalization correlate with life history or metabolic rate in Carnivora?

PubMed Central

Finarelli, John A.

2010-01-01

A recent analysis of brain size evolution reconstructed the plesiomorphic brain–body size allometry for the mammalian order Carnivora, providing an important reference frame for comparative analyses of encephalization (brain volume scaled to body mass). I performed phylogenetically corrected regressions to remove the effects of body mass, calculating correlations between residual values of encephalization with basal metabolic rate (BMR) and six life-history variables (gestation time, neonatal mass, weaning time, weaning mass, litter size, litters per year). No significant correlations were recovered between encephalization and any life-history variable or BMR, arguing against hypotheses relating encephalization to maternal energetic investment. However, after correcting for clade-specific adaptations, I recovered significant correlations for several variables, and further analysis revealed a conserved carnivoran reproductive strategy, linking degree of encephalization to the well-documented mammalian life-history trade-off between neonatal mass and litter size. This strategy of fewer, larger offspring correlating with increased encephalization remains intact even after independent changes in encephalization allometries in the evolutionary history of this clade. PMID:20007169

The Intestinal Microbiome in Early Life: Health and Disease

PubMed Central

Arrieta, Marie-Claire; Stiemsma, Leah T.; Amenyogbe, Nelly; Brown, Eric M.; Finlay, Brett

2014-01-01

Human microbial colonization begins at birth and continues to develop and modulate in species abundance for about 3 years, until the microbiota becomes adult-like. During the same time period, children experience significant developmental changes that influence their health status as well as their immune system. An ever-expanding number of articles associate several diseases with early-life imbalances of the gut microbiota, also referred to as gut microbial dysbiosis. Whether early-life dysbiosis precedes and plays a role in disease pathogenesis, or simply originates from the disease process itself is a question that is beginning to be answered in a few diseases, including IBD, obesity, and asthma. This review describes the gut microbiome structure and function during the formative first years of life, as well as the environmental factors that determine its composition. It also aims to discuss the recent advances in understanding the role of the early-life gut microbiota in the development of immune-mediated, metabolic, and neurological diseases. A greater understanding of how the early-life gut microbiota impacts our immune development could potentially lead to novel microbial-derived therapies that target disease prevention at an early age. PMID:25250028

Maternal genetic effects on adaptive divergence between anadromous and resident brook charr during early life history.

PubMed

Perry, G M L; Audet, C; Bernatchez, L

2005-09-01

The importance of directional selection relative to neutral evolution may be determined by comparing quantitative genetic variation in phenotype (Q(ST)) to variation at neutral molecular markers (F(ST)). Quantitative divergence between salmonid life history types is often considerable, but ontogenetic changes in the significance of major sources of genetic variance during post-hatch development suggest that selective differentiation varies by developmental stage. In this study, we tested the hypothesis that maternal genetic differentiation between anadromous and resident brook charr (Salvelinus fontinalis Mitchill) populations for early quantitative traits (embryonic size/growth, survival, egg number and developmental time) would be greater than neutral genetic differentiation, but that the maternal genetic basis for differentiation would be higher for pre-resorption traits than post-resorption traits. Quantitative genetic divergence between anadromous (seawater migratory) and resident Laval River (Québec) brook charr based on maternal genetic variance was high (Q(ST) > 0.4) for embryonic length, yolk sac volume, embryonic growth rate and time to first response to feeding relative to neutral genetic differentiation [F(ST) = 0.153 (0.071-0.214)], with anadromous females having positive genetic coefficients for all of the above characters. However, Q(ST) was essentially zero for all traits post-resorption of the yolk sac. Our results indicate that the observed divergence between resident and anadromous brook charr has been driven by directional selection, and may therefore be adaptive. Moreover, they provide among the first evidence that the relative importance of selective differentiation may be highly context-specific, and varies by genetic contributions to phenotype by parental sex at specific points in offspring ontogeny. This in turn suggests that interpretations of Q(ST)-F(ST) comparisons may be improved by considering the structure of quantitative genetic

Trans-Agency Early-Life Exposures and Cancer Working Group

Cancer.gov

The Trans-Agency Early-Life Exposures and Cancer Working Group promotes integration of early-life events and exposures into public health cancer research, control, prevention, and policy strategies to reduce the cancer burden in the United States and globally.

Impacts of ocean acidification on early life-history stages and settlement of the coral-eating sea star Acanthaster planci.

PubMed

Uthicke, Sven; Pecorino, Danilo; Albright, Rebecca; Negri, Andrew Peter; Cantin, Neal; Liddy, Michelle; Dworjanyn, Symon; Kamya, Pamela; Byrne, Maria; Lamare, Miles

2013-01-01

Coral reefs are marine biodiversity hotspots, but their existence is threatened by global change and local pressures such as land-runoff and overfishing. Population explosions of coral-eating crown of thorns sea stars (COTS) are a major contributor to recent decline in coral cover on the Great Barrier Reef. Here, we investigate how projected near-future ocean acidification (OA) conditions can affect early life history stages of COTS, by investigating important milestones including sperm motility, fertilisation rates, and larval development and settlement. OA (increased pCO2 to 900-1200 µatm pCO2) significantly reduced sperm motility and, to a lesser extent, velocity, which strongly reduced fertilization rates at environmentally relevant sperm concentrations. Normal development of 10 d old larvae was significantly lower under elevated pCO2 but larval size was not significantly different between treatments. Settlement of COTS larvae was significantly reduced on crustose coralline algae (known settlement inducers of COTS) that had been exposed to OA conditions for 85 d prior to settlement assays. Effect size analyses illustrated that reduced settlement may be the largest bottleneck for overall juvenile production. Results indicate that reductions in fertilisation and settlement success alone would reduce COTS population replenishment by over 50%. However, it is unlikely that this effect is sufficient to provide respite for corals from other negative anthropogenic impacts and direct stress from OA and warming on corals.

Density-dependence interacts with extrinsic mortality in shaping life histories

PubMed Central

Burger, Oskar; Kozłowski, Jan

2017-01-01

The role of extrinsic mortality in shaping life histories is poorly understood. However, substantial evidence suggests that extrinsic mortality interacts with density-dependence in crucial ways. We develop a model combining Evolutionarily Stable Strategies with a projection matrix that allows resource allocation to growth, tissue repairs, and reproduction. Our model examines three cases, with density-dependence acting on: (i) mortality, (ii) fecundity, and (iii) production rate. We demonstrate that density-independent extrinsic mortality influences the rate of aging, age at maturity, growth rate, and adult size provided that density-dependence acts on fertility or juvenile mortality. However, density-independent extrinsic mortality has no effect on these life history traits when density-dependence acts on survival. We show that extrinsic mortality interacts with density-dependence via a compensation mechanism: the higher the extrinsic mortality the lower the strength of density-dependence. However, this compensation fully offsets the effect of extrinsic mortality only if density-dependence acts on survival independently of age. Both the age-pattern and the type of density-dependence are crucial for shaping life history traits. PMID:29049399

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

Early-Life State-of-Residence Characteristics and Later Life Hypertension, Diabetes, and Ischemic Heart Disease.

PubMed

Rehkopf, David H; Eisen, Ellen A; Modrek, Sepideh; Mokyr Horner, Elizabeth; Goldstein, Benjamin; Costello, Sadie; Cantley, Linda F; Slade, Martin D; Cullen, Mark R

2015-08-01

We examined how state characteristics in early life are associated with individual chronic disease later in life. We assessed early-life state of residence using the first 3 digits of social security numbers from blue- and white-collar workers from a US manufacturing company. Longitudinal data were available from 1997 to 2012, with 305 936 person-years of observation. Disease was assessed using medical claims. We modeled associations using pooled logistic regression with inverse probability of censoring weights. We found small but statistically significant associations between early-state-of-residence characteristics and later life hypertension, diabetes, and ischemic heart disease. The most consistent associations were with income inequality, percentage non-White, and education. These associations were similar after statistically controlling for individual socioeconomic and demographic characteristics and current state characteristics. Characteristics of the state in which an individual lives early in life are associated with prevalence of chronic disease later in life, with a strength of association equivalent to genetic associations found for these same health outcomes.

Seed after-ripening and dormancy determine adult life history independently of germination timing.

PubMed

de Casas, Rafael Rubio; Kovach, Katherine; Dittmar, Emily; Barua, Deepak; Barco, Brenden; Donohue, Kathleen

2012-05-01

• Seed dormancy can affect life history through its effects on germination time. Here, we investigate its influence on life history beyond the timing of germination. • We used the response of Arabidopsis thaliana to chilling at the germination and flowering stages to test the following: how seed dormancy affects germination responses to the environment; whether variation in dormancy affects adult phenology independently of germination time; and whether environmental cues experienced by dormant seeds have an effect on adult life history. • Dormancy conditioned the germination response to low temperatures, such that prolonged periods of chilling induced dormancy in nondormant seeds, but stimulated germination in dormant seeds. The alleviation of dormancy through after-ripening was associated with earlier flowering, independent of germination date. Experimental dormancy manipulations showed that prolonged chilling at the seed stage always induced earlier flowering, regardless of seed dormancy. Surprisingly, this effect of seed chilling on flowering time was observed even when low temperatures did not induce germination. • In summary, seed dormancy influences flowering time and hence life history independent of its effects on germination timing. We conclude that the seed stage has a pronounced effect on life history, the influence of which goes well beyond the timing of germination. © 2012 The Authors. New Phytologist © 2012 New Phytologist Trust.

Trait shifts associated with the subshrub life-history strategy in a tropical savanna.

PubMed

Giroldo, A B; Scariot, A; Hoffmann, W A

2017-10-01

Over the past 10 million years, tropical savanna environments have selected for small growth forms within woody plant lineages. The result has been the evolution of subshrubs (geoxyles), presumably as an adaptation to frequent fire. To evaluate the traits associated with the shift from tree to subshrub growth forms, we compared seed biomass, germination, survival, resprouting, biomass allocation, and photosynthesis between congeneric trees and subshrubs, and quantified phylogenetic conservatism. Despite large differences in adult morphology between trees and subshrub species, the differences are modest in seedlings, and most of the variation in traits was explained by genus, indicating considerable phylogenic conservatism. Regardless, tree seedlings invested more heavily in aboveground growth, compared to subshrubs, which is consistent with the adult strategy of savanna trees, which depend on a large resistant-fire stem. Subshrub seedlings also invest in greater non-structural carbohydrate reserves, likely as an adaptation to the high fire frequencies typical of tropical savannas. The modest differences as seedlings suggest that selective pressures during early development may not have contributed substantially to the evolution of the subshrub growth form and that the distinct allocation and life history must arise later in life. This is consistent with the interpretation that the subshrub growth form arose as a life-history strategy in which maturity is reached at a small stem size, allowing them to reproduce despite repeated fire-induced topkill. The convergent evolution of subshrubs within multiple tree lineages reaffirms the importance of fire in the origin and diversification of the flora of mesic savannas.

"It's Not Much of a Life": The Benefits and Ethics of Using Life History Methods With People Who Inject Drugs in Qualitative Harm Reduction Research.

PubMed

Harris, Magdalena; Rhodes, Tim

2018-06-01

A life history approach enables study of how risk or health protection is shaped by critical transitions and turning points in a life trajectory and in the context of social environment and time. We employed visual and narrative life history methods with people who inject drugs to explore how hepatitis C protection was enabled and maintained over the life course. We overview our methodological approach, with a focus on the ethics in practice of using life history timelines and life-grids with 37 participants. The life-grid evoked mixed emotions for participants: pleasure in receiving a personalized visual history and pain elicited by its contents. A minority managed this pain with additional heroin use. The methodological benefits of using life history methods and visual aids have been extensively reported. Crucial to consider are the ethical implications of this process, particularly for people who lack socially ascribed markers of a "successful life."

New perspectives in the history of twentieth-century life sciences: historical, historiographical and epistemological themes.

PubMed

Meunier, Robert; Nickelsen, Kärin

2018-01-18

The history of twentieth-century life sciences is not exactly a new topic. However, in view of the increasingly rapid development of the life sciences themselves over the past decades, some of the well-established narratives are worth revisiting. Taking stock of where we stand on these issues was the aim of a conference in 2015, entitled "Perspectives for the History of Life Sciences" (Munich, Oct 30-Nov 1, 2015). The papers in this topical collection are based on work presented and discussed at and around this meeting. Just as the conference, the collection aims at exploring fields in the history of life sciences that appear understudied, sources that have been overlooked, and novel ways of engaging with this material. The papers convened in this collection may not be representative of the field as a whole; but we feel that they do indicate some elements that have received emphasis in recent years, and may become more central in the years to come, such as the history of previously neglected contexts and domains of the life sciences, the question of continuity and change on the level of practices, the history of complexity and diversity in twentieth-century life sciences and the reconsideration of the relationship between history and philosophy of life sciences.

An Impaired View of Earth's Early History

NASA Astrophysics Data System (ADS)

Vervoort, J. D.; Kemp, A. I.; Bauer, A.; Bowring, S. A.; Fisher, C.

2014-12-01

The Hf and Nd isotope records of Earth's early history are sparse, difficult to interpret, and controversial, much like the few remnants of crust older than 4 Ga. New analytical techniques have been brought to bear on this problem but despite this recent work­-or, perhaps, because of it-the record is no clearer than it was 15 years ago. Several studies, based on highly variable calculated initial isotopic compositions, have argued for highly heterogeneous crust and mantle reservoirs in the early Earth1,2 and an ultra-depleted Eoarchean mantle3. These data come mostly from two sources: Hf-Nd isotope analyses of ultramafic rocks and Hf isotope analyses of zircons by solution or laser ablation. An important question for understanding the chemical evolution of the early Earth is: Do these data offer a unique window into the early Earth or are they artefacts not representative of crust/mantle evolution, giving an impaired view of the Earth's early history? In complex samples, measured isotopic compositions can result from open-system behavior in easily altered ultramafic compositions, in multicomponent, polymetamorphic gneisses, or in zircons with multiple generations of growth. Perhaps most importantly, accurate age assignment is often lacking, compromised, or impossible in these rocks, making calculation of initial epsilon Hf and Nd values ambiguous at best. In order to gain insight into crust mantle evolution in the early Earth we need, above all, a robust and unambiguous isotopic record to work with. This can be achieved by integrating zircon U-Pb and Hf and whole-rock Hf and Nd isotope compositions in relatively undisturbed igneous rocks with well-constrained ages. When this approach is used apparent isotopic heterogeneity decreases and a simpler model for crust-mantle evolution in the early Earth emerges. Careful screening of geological relationships, petrology, and geochemistry of samples from the early Earth should be done before interpreting isotopic data

Instrumental learning and cognitive flexibility processes are impaired in children exposed to early life stress.

PubMed

Harms, Madeline B; Shannon Bowen, Katherine E; Hanson, Jamie L; Pollak, Seth D

2017-10-19

Children who experience severe early life stress show persistent deficits in many aspects of cognitive and social adaptation. Early stress might be associated with these broad changes in functioning because it impairs general learning mechanisms. To explore this possibility, we examined whether individuals who experienced abusive caregiving in childhood had difficulties with instrumental learning and/or cognitive flexibility as adolescents. Fifty-three 14-17-year-old adolescents (31 exposed to high levels of childhood stress, 22 control) completed an fMRI task that required them to first learn associations in the environment and then update those pairings. Adolescents with histories of early life stress eventually learned to pair stimuli with both positive and negative outcomes, but did so more slowly than their peers. Furthermore, these stress-exposed adolescents showed markedly impaired cognitive flexibility; they were less able than their peers to update those pairings when the contingencies changed. These learning problems were reflected in abnormal activity in learning- and attention-related brain circuitry. Both altered patterns of learning and neural activation were associated with the severity of lifetime stress that the adolescents had experienced. Taken together, the results of this experiment suggest that basic learning processes are impaired in adolescents exposed to early life stress. These general learning mechanisms may help explain the emergence of social problems observed in these individuals. © 2017 The Authors. Developmental Science Published by John Wiley & Sons Ltd.

Early life adversity potentiates the effects of later life stress on cumulative physiological dysregulation.

PubMed

Dich, Nadya; Hansen, Åse Marie; Avlund, Kirsten; Lund, Rikke; Mortensen, Erik Lykke; Bruunsgaard, Helle; Rod, Naja Hulvej

2015-01-01

Previous research indicates that early life adversity may heighten stress reactivity and impair mechanisms for adaptive coping, suggesting that experience of stress in early life may also potentiate adults' physiological vulnerability to stress in later life. The study tested this hypothesis by investigating whether the experience of stressful events and circumstances (SEC) in childhood or adolescence amplified the effect of adulthood SEC on physiological dysregulation (allostatic load, AL) in later midlife. Observational data were used in the present study. Physiological functioning was measured in later midlife (participants' age ranged from 49 to 63 years). Both childhood/adolescence and adulthood SEC were reported retrospectively on the same occasion. Participants were 5309 Danish men and women from Copenhagen Aging and Midlife Biobank (CAMB). SEC included socioeconomic and family factors. The AL index was based on nine cardiovascular, metabolic, and immune biomarkers. Experience of SEC in both early life and adulthood independently predicted higher AL. In men, experience of SEC in early life also potentiated the effect of SEC in adulthood on AL. The results provide further insight into the mechanisms behind the "biological embedding" of childhood stress.

Attachment within life history theory: an evolutionary perspective on individual differences in attachment.

PubMed

Szepsenwol, Ohad; Simpson, Jeffry A

2018-03-15

In this article, we discuss theory and research on how individual differences in adult attachment mediate the adaptive calibration of reproductive strategies, cognitive schemas, and emotional expression and regulation. We first present an integration of attachment theory and life history theory. Then, we discuss how early harsh and/or unpredictable environments may promote insecure attachment by hampering parents' ability to provide sensitive and reliable care to their children. Finally, we discuss how, in the context of harsh and/or unpredictable environments, different types of insecure attachment (i.e. anxiety and avoidance) may promote evolutionary adaptive reproductive strategies, cognitive schemas, and emotional expression and regulation profiles. Copyright © 2018 Elsevier Ltd. All rights reserved.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dunham, A.E.; Overall, K.L.; Forster, C.A.

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.

Bridging scales in the evolution of infectious disease life histories: application.

PubMed

Mideo, Nicole; Nelson, William A; Reece, Sarah E; Bell, Andrew S; Read, Andrew F; Day, Troy

2011-11-01

Within- and between-host disease processes occur on the same timescales, therefore changes in the within-host dynamics of parasites, resources, and immunity can interact with changes in the epidemiological dynamics to affect evolutionary outcomes. Consequently, studies of the evolution of disease life histories, that is, infection-age-specific patterns of transmission and virulence, have been constrained by the need for a mechanistic understanding of within-host disease dynamics. In a companion paper (Day et al. 2011), we develop a novel approach that quantifies the relevant within-host aspects of disease through genetic covariance functions. Here, we demonstrate how to apply this theory to data. Using two previously published datasets from rodent malaria infections, we show how to translate experimental measures into disease life-history traits, and how to quantify the covariance in these traits. Our results show how patterns of covariance can interact with epidemiological dynamics to affect evolutionary predictions for disease life history. We also find that the selective constraints on disease life-history evolution can vary qualitatively, and that "simple" virulence-transmission trade-offs that are often the subject of experimental investigation can be obscured by trade-offs within one trait alone. Finally, we highlight the type and quality of data required for future applications. © 2011 The Author(s). Evolution© 2011 The Society for the Study of Evolution.

An organismal concept for Sengelia radicans gen. et sp. nov. - morphology and natural history of an Early Devonian lycophyte.

PubMed

Matsunaga, Kelly K S; Tomescu, Alexandru M F

2017-05-01

Fossil plants are found as fragmentary remains and understanding them as natural species requires assembly of whole-organism concepts that integrate different plant parts. Such concepts are essential for incorporating fossils in hypotheses of plant evolution and phylogeny. Plants of the Early Devonian are crucial to reconstructing the initial radiation of tracheophytes, yet few are understood as whole organisms. This study assembles a whole-plant concept for the Early Devonian lycophyte Sengelia radicans gen. et sp. nov., based on morphometric data and taphonomic observations from >1000 specimens collected in the Beartooth Butte Formation (Wyoming, USA). Sengelia radicans occupies a key position between stem-group and derived lycophyte lineages. Sengelia had a rooting system of downward-growing root-bearing stems, formed dense monotypic mats of prostrate shoots in areas that experienced periodic flooding, and was characterized by a life-history strategy adapted for survival after floods, dominated by clonality, and featuring infrequent sexual reproduction. Sengelia radicans is the oldest among the very few early tracheophytes for which a detailed, rigorous whole-plant concept integrates morphology, growth habit, life history and growth environment. This plant adds to the diversity of body plans documented among lycophytes and may help elucidate patterns of morphological evolution in the clade. © The Author 2017. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com

Linkages between mitochondrial lipids and life history in temperate and tropical birds.

PubMed

Calhoon, Elisabeth A; Jimenez, Ana Gabriela; Harper, James M; Jurkowitz, Marianne S; Williams, Joseph B

2014-01-01

Temperate birds tend to have a fast pace of life and short life spans with high reproductive output, whereas tropical birds tend to have a slower pace of life, invest fewer resources in reproduction, and have higher adult survival rates. How these differences in life history at the organismal level are rooted in differences at the cellular level is a major focus of current research. Here, we cultured fibroblasts from phylogenetically paired tropical and temperate species, isolated mitochondria from each, and compared their mitochondrial membrane lipids. We also correlated the amounts of these lipids with an important life history parameter, clutch size. We found that tropical birds tended to have less mitochondrial lipid per cell, especially less cardiolipin per cell, suggesting that cells from tropical birds have fewer mitochondria or less inner mitochondrial membrane per cell. We also found that the mitochondria of tropical birds and the species with the smallest clutch sizes had higher amounts of plasmalogens, a lipid that could serve as an antioxidant. Overall, our findings are consistent with the idea that there are underlying molecular and cellular physiological traits that could account for the differences in whole-animal physiology between animals with different life histories.

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.

How Metamorphosis Is Different in Plethodontids: Larval Life History Perspectives on Life-Cycle Evolution

PubMed Central

Beachy, Christopher K.; Ryan, Travis J.; Bonett, Ronald M.

2017-01-01

Plethodontid salamanders exhibit biphasic, larval form paedomorphic, and direct developing life cycles. This diversity of developmental strategies exceeds that of any other family of terrestrial vertebrate. Here we compare patterns of larval development among the three divergent lineages of biphasic plethodontids and other salamanders. We discuss how patterns of life-cycle evolution and larval ecology might have produced a wide array of larval life histories. Compared with many other salamanders, most larval plethodontids have relatively slow growth rates and sometimes exceptionally long larval periods (up to 60 mo). Recent phylogenetic analyses of life-cycle evolution indicate that ancestral plethodontids were likely direct developers. If true, then biphasic and paedomorphic lineages might have been independently derived through different developmental mechanisms. Furthermore, biphasic plethodontids largely colonized stream habitats, which tend to have lower productivity than seasonally ephemeral ponds. Consistent with this, plethodontid larvae grow very slowly, and metamorphic timing does not appear to be strongly affected by growth history. On the basis of this, we speculate that feeding schedules and stress hormones might play a comparatively reduced role in governing the timing of metamorphosis of stream-dwelling salamanders, particularly plethodontids. PMID:29269959

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. Copyright © 2013 Elsevier Ltd. All rights reserved.

The reproductive biology and early life ecology of a common Caribbean brain coral, Diploria labyrinthiformis (Scleractinia: Faviinae)

NASA Astrophysics Data System (ADS)

Chamberland, Valérie F.; Snowden, Skylar; Marhaver, Kristen L.; Petersen, Dirk; Vermeij, Mark J. A.

2017-03-01

Despite the fact that most of the severe demographic bottlenecks in coral populations occur during their earliest life stages, information on the reproductive biology and early life history traits of many coral species is limited and often inferred from adult traits only. This study reports on several atypical aspects of the reproductive biology and early life ecology of the grooved brain coral, Diploria labyrinthiformis (Linnaeus, 1758), a conspicuous reef-building species on Caribbean reefs. The timing of gamete release of D. labyrinthiformis was monitored in Curaçao over eight consecutive months, and embryogenesis, planulae behavior, and settlement rates were observed and quantified. We further studied growth and symbiont acquisition in juvenile D. labyrinthiformis for 3.5 yr and compared settler survival under ambient and nutrient-enriched conditions in situ. Notably, D. labyrinthiformis reproduced during daylight hours in six consecutive monthly spawning events between May and September 2013, with a peak in June. This is the largest number of reproductive events per year ever observed in a broadcast-spawning Caribbean coral species. In settlement experiments, D. labyrinthiformis planulae swam to the bottom of culture containers 13 h after spawning and rapidly settled when provided with settlement cues (42% within 14 h). After 5 months, the survival and growth rates of settled juveniles were 3.7 and 1.9 times higher, respectively, for settlers that acquired zooxanthellae within 1 month after settlement, compared to those that acquired symbionts later on. Nutrient enrichment increased settler survival fourfold, but only for settlers that had acquired symbionts within 1 month after settlement. With at least six reproductive events per year, a short planktonic larval phase, high settlement rates, and a positive response to nutrient enrichment, the broadcast-spawning species D. labyrinthiformis displays a range of reproductive and early life-history traits that

The life-history trade-off between fertility and child survival

PubMed Central

Lawson, David W.; Alvergne, Alexandra; Gibson, Mhairi A.

2012-01-01

Evolutionary models of human reproduction argue that variation in fertility can be understood as the local optimization of a life-history trade-off between offspring quantity and ‘quality’. Child survival is a fundamental dimension of quality in these models as early-life mortality represents a crucial selective bottleneck in human evolution. This perspective is well-rehearsed, but current literature presents mixed evidence for a trade-off between fertility and child survival, and little empirical ground to evaluate how socioecological and individual characteristics influence the benefits of fertility limitation. By compiling demographic survey data, we demonstrate robust negative relationships between fertility and child survival across 27 sub-Saharan African countries. Our analyses suggest this relationship is primarily accounted for by offspring competition for parental investment, rather than by reverse causal mechanisms. We also find that the trade-off increases in relative magnitude as national mortality declines and maternal somatic (height) and extrasomatic (education) capital increase. This supports the idea that socioeconomic development, and associated reductions in extrinsic child mortality, favour reduced fertility by increasing the relative returns to parental investment. Observed fertility, however, falls considerably short of predicted optima for maximizing total offspring survivorship, strongly suggesting that additional unmeasured costs of reproduction ultimately constrain the evolution of human family size. PMID:23034700

[The early history of "Ecstasy"].

PubMed

Benzenhöfer, U; Passie, T

2006-01-01

There is no consensus in the literature regarding the early history of MDMA (Methylendioxymethamphetamine, so-called "Ecstasy"). Various authors credit the first synthesis of MDMA to the German chemist Fritz Haber, but it appears neither in his doctoral thesis (Berlin 1891) nor in his accompanying articles. The man who first synthesized MDMA was the chemist Dr. Anton Köllisch, who worked for the German pharmaceutical company Merck. He created MDMA as a by-product while trying to synthesize hydrastinin, a styptic substance. In 1912, Merck filed to patent the applied method of preparation. The patent was issued in 1914, yet no pharmaceutical testing followed at that time.

Functional linkages for the pace of life, life-history, and environment in birds.

PubMed

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

2010-11-01

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

Commentary: On the Importance of Early Life Cognitive Abilities in Shaping Later Life Outcomes.

PubMed

Hofer, Scott M; Clouston, Sean

2014-01-01

Early life cognitive ability is likely to be dynamically related to life course factors including educational attainment, occupational outcomes, health behaviors, activities, health, and subsequent cognitive health. Disentangling the selective and causal processes contributing to cognitive functioning across the lifespan is challenging and requires long-term investments in longitudinal data. We discuss results from several analyses using data from the Individual Development and Adaptation longitudinal research program (Bergman, 2000; Magnusson, 1988) that provide fresh insights into the relation of early life cognition, particularly high levels of cognitive capabilities, to educational achievement, emotional adjustment, and career success. These papers and the longitudinal data provide a remarkable window into the development and impacts of cognition, and high cognitive functioning, on a variety of important life outcomes that we hope will continue to inform us about additional outcomes in middle life, transition to retirement, and cognition and health in later years and to robustly examine how the early years matter across the whole lifespan.

[Contribution to the history of pharmacology (the early Roman empire)].

PubMed

Tesařová, Drahomíra

2014-01-01

This article is a contribution to the history of pharmacology in the early Roman empire. It contains texts mainly written in Latin: the works of Aulus Cornelius Celsus, Scribonius Largus and Plinius Maior (Pliny the Elder). It describes their structure and contributions to the history of medicine and gives examples of some prescriptions and drugs in the original language and in Czech.

Largely flat latitudinal life history clines in the dung fly Sepsis fulgens across Europe (Diptera: Sepsidae).

PubMed

Roy, Jeannine; Blanckenhorn, Wolf U; Rohner, Patrick T

2018-05-17

Clinal variation in body size and related life history traits is common and has stimulated the postulation of several eco-geographical rules. Whereas some clinal patterns are clearly adaptive, the causes of others remain obscure. We investigated intra-specific body size, development time and female fecundity (egg size and number) clines across 13 European populations of the dung fly Sepsis fulgens spanning 20° latitude from southern Italy to Estonia in a genetic common garden approach. Despite very short generation times (ca. 2 weeks at 24 °C), we found a converse Bergmann cline (smaller size at higher latitudes). As development time did not change with latitude (flat cline), integral growth rate thus likely declines towards the pole. At the same time, early fecundity, but not egg size, increased with latitude. Rather than being mediated by seasonal time constraints, the body size reduction in the northernmost flies from Estonia could suggest that these are marginal, edge populations, as when omitting them the body size cline became flat as well. Most of the other sepsid species investigated to date also show flat body size clines, a pattern that strikingly differs from Drosophila. We conclude that S. fulgens life history traits appear to be shaped by similar environmental pressures and selective mechanisms across Europe, be they adaptive or not. This reiterates the suggestion that body size clines can result as a secondary consequence of selection pressures shaping an entire life history syndrome, rendering them inconsistent and unpredictable in general.

Primate enamel evinces long period biological timing and regulation of life history.

PubMed

Bromage, Timothy G; Hogg, Russell T; Lacruz, Rodrigo S; Hou, Chen

2012-07-21

The factor(s) regulating the combination of traits that define the overall life history matrix of mammalian species, comprising attributes such as brain and body weight, age at sexual maturity, lifespan and others, remains a complete mystery. The principal objectives of the present research are (1) to provide evidence for a key variable effecting life history integration and (2) to provide a model for how one would go about investigating the metabolic mechanisms responsible for this rhythm. We suggest here that a biological rhythm with a period greater than the circadian rhythm is responsible for observed variation in primate life history. Evidence for this rhythm derives from studies of tooth enamel formation. Enamel contains an enigmatic periodicity in its microstructure called the striae of Retzius, which develops at species specific intervals in units of whole days. We refer to this enamel rhythm as the repeat interval (RI). For primates, we identify statistically significant relationships between RI and all common life history traits. Importantly, RI also correlates with basal and specific metabolic rates. With the exception of estrous cyclicity, all relationships share a dependence upon body mass. This dependence on body mass informs us that some aspect of metabolism is responsible for periodic energy allocations at RI timescales, regulating cell proliferation rates and growth, thus controlling the pace, patterning, and co-variation of life history traits. Estrous cyclicity relates to the long period rhythm in a body mass-independent manner. The mass-dependency and -independency of life history relationships with RI periodicity align with hypothalamic-mediated neurosecretory anterior and posterior pituitary outputs. We term this period the Havers-Halberg Oscillation (HHO), in reference to Clopton Havers, a 17th Century hard tissue anatomist, and Franz Halberg, a long-time explorer of long-period rhythms. We propose a mathematical model that may help elucidate

Early cranial ultrasound changes as predictors of outcome during first year of life in term infants with perinatal asphyxia.

PubMed

Boo, N Y; Chandran, V; Zulfiqar, M A; Zamratol, S M; Nyein, M K; Haliza, M S; Lye, M S

2000-08-01

To identify the types of early cranial ultrasound changes that were significant predictors of adverse outcome during the first year of life in asphyxiated term infants. This was a prospective cohort study. Shortly after birth, cranial ultrasonography was carried out via the anterior fontanelles of 70 normal control infants and 104 asphyxiated infants with a history of fetal distress and Apgar scores of less than 6 at 1 and 5 min of life, or requiring endotracheal intubation and manual intermittent positive pressure ventilation for at least 5 min after birth. Neurodevelopmental assessment was carried out on the survivors at 1 year of age. Abnormal cranial ultrasound changes were detected in a significantly higher proportion (79.8%, or n = 83) of asphyxiated infants than controls (39.5%, or n = 30) (P < 0.0001). However, logistic regression analysis showed that only three factors were significantly associated with adverse outcome at 1 year of life among the asphyxiated infants. These were: (i) decreasing birthweight (for every additional gram of increase in birthweight, adjusted odds ratio (OR) = 0.999, 95% confidence interval (CI) 0.998, 1.000; P = 0.047); (ii) a history of receiving ventilatory support during the neonatal period (adjusted OR = 8.3; 95%CI 2.4, 28.9; P = 0.0009); and (iii) hypoxic-ischaemic encephalopathy stage 2 or 3 (adjusted OR = 5.8; 95%CI 1.8, 18.6; P = 0.003). None of the early cranial ultrasound changes was a significant predictor. Early cranial ultrasound findings, although common in asphyxiated infants, were not significant predictors of adverse outcome during the first year of life in asphyxiated term infants.

Exploring the Experience of Life Stress Among Black Women with a History of Fetal or Infant Death: a Phenomenological Study.

PubMed

Brown, Kyrah K; Lewis, Rhonda K; Baumgartner, Elizabeth; Schunn, Christy; Maryman, J'Vonnah; LoCurto, Jamie

2017-06-01

Disparate birth outcomes among Black women continue to be a major public health problem. Whereas prior research has investigated the influence of stress on Black women's birth outcomes, few studies have explored how stress is experienced among Black women across the life course. The objectives of this study were to describe the experience of stress across the life course among Black women who reported a history of fetal or infant death and to identify stressful life events (SLE) that may not be represented in the widely used SLE inventory. Using phenomenological, qualitative research design, in-depth interviews were conducted with six Black women in Kansas who experienced a fetal or infant death. Analyses revealed that participants experienced multiple, co-occurring stressors over the course of their lives and experienced a proliferation of stress emerging in early life and persisting into adulthood. Among the types of stressors cited by participants, history of sexual assault (trauma-related stressor) was a key stressful life event that is not currently reflected in the SLE inventory. Our findings highlight the importance of using a life-course perspective to gain a contextual understanding of the experiences of stress among Black women, particularly those with a history of adverse birth outcomes. Further research investigating Black women's experiences of stress and the mechanisms by which stress impacts their health could inform efforts to reduce disparities in birth outcomes. An additional focus on the experience and impact of trauma-related stress on Black women's birth outcomes may also be warranted.

Unification theory of optimal life histories and linear demographic models in internal stochasticity.

PubMed

Oizumi, Ryo

2014-01-01

Life history of organisms is exposed to uncertainty generated by internal and external stochasticities. Internal stochasticity is generated by the randomness in each individual life history, such as randomness in food intake, genetic character and size growth rate, whereas external stochasticity is due to the environment. For instance, it is known that the external stochasticity tends to affect population growth rate negatively. It has been shown in a recent theoretical study using path-integral formulation in structured linear demographic models that internal stochasticity can affect population growth rate positively or negatively. However, internal stochasticity has not been the main subject of researches. Taking account of effect of internal stochasticity on the population growth rate, the fittest organism has the optimal control of life history affected by the stochasticity in the habitat. The study of this control is known as the optimal life schedule problems. In order to analyze the optimal control under internal stochasticity, we need to make use of "Stochastic Control Theory" in the optimal life schedule problem. There is, however, no such kind of theory unifying optimal life history and internal stochasticity. This study focuses on an extension of optimal life schedule problems to unify control theory of internal stochasticity into linear demographic models. First, we show the relationship between the general age-states linear demographic models and the stochastic control theory via several mathematical formulations, such as path-integral, integral equation, and transition matrix. Secondly, we apply our theory to a two-resource utilization model for two different breeding systems: semelparity and iteroparity. Finally, we show that the diversity of resources is important for species in a case. Our study shows that this unification theory can address risk hedges of life history in general age-states linear demographic models.

Unification Theory of Optimal Life Histories and Linear Demographic Models in Internal Stochasticity

PubMed Central

Oizumi, Ryo

2014-01-01

Life history of organisms is exposed to uncertainty generated by internal and external stochasticities. Internal stochasticity is generated by the randomness in each individual life history, such as randomness in food intake, genetic character and size growth rate, whereas external stochasticity is due to the environment. For instance, it is known that the external stochasticity tends to affect population growth rate negatively. It has been shown in a recent theoretical study using path-integral formulation in structured linear demographic models that internal stochasticity can affect population growth rate positively or negatively. However, internal stochasticity has not been the main subject of researches. Taking account of effect of internal stochasticity on the population growth rate, the fittest organism has the optimal control of life history affected by the stochasticity in the habitat. The study of this control is known as the optimal life schedule problems. In order to analyze the optimal control under internal stochasticity, we need to make use of “Stochastic Control Theory” in the optimal life schedule problem. There is, however, no such kind of theory unifying optimal life history and internal stochasticity. This study focuses on an extension of optimal life schedule problems to unify control theory of internal stochasticity into linear demographic models. First, we show the relationship between the general age-states linear demographic models and the stochastic control theory via several mathematical formulations, such as path–integral, integral equation, and transition matrix. Secondly, we apply our theory to a two-resource utilization model for two different breeding systems: semelparity and iteroparity. Finally, we show that the diversity of resources is important for species in a case. Our study shows that this unification theory can address risk hedges of life history in general age-states linear demographic models. PMID:24945258

Molecular Evolution of Aminoacyl tRNA Synthetase Proteins in the Early History of Life

NASA Astrophysics Data System (ADS)

Fournier, Gregory P.; Andam, Cheryl P.; Alm, Eric J.; Gogarten, J. Peter

2011-12-01

Aminoacyl-tRNA synthetases (aaRS) consist of several families of functionally conserved proteins essential for translation and protein synthesis. Like nearly all components of the translation machinery, most aaRS families are universally distributed across cellular life, being inherited from the time of the Last Universal Common Ancestor (LUCA). However, unlike the rest of the translation machinery, aaRS have undergone numerous ancient horizontal gene transfers, with several independent events detected between domains, and some possibly involving lineages diverging before the time of LUCA. These transfers reveal the complexity of molecular evolution at this early time, and the chimeric nature of genomes within cells that gave rise to the major domains. Additionally, given the role of these protein families in defining the amino acids used for protein synthesis, sequence reconstruction of their pre-LUCA ancestors can reveal the evolutionary processes at work in the origin of the genetic code. In particular, sequence reconstructions of the paralog ancestors of isoleucyl- and valyl- RS provide strong empirical evidence that at least for this divergence, the genetic code did not co-evolve with the aaRSs; rather, both amino acids were already part of the genetic code before their cognate aaRSs diverged from their common ancestor. The implications of this observation for the early evolution of RNA-directed protein biosynthesis are discussed.

Microanatomy and life history in Palaeopleurosaurus (Rhynchocephalia: Pleurosauridae) from the Early Jurassic of Germany

NASA Astrophysics Data System (ADS)

Klein, Nicole; Scheyer, Torsten M.

2017-02-01

The tuatara ( Sphenodon punctatus) from New Zealand is often—erroneously—identified as a `living fossil', although it is the lone survivor of a large, successful radiation of Rhynchocephalia, sister taxon to squamates (lizards and snakes), that thrived through the Mesozoic and Cenozoic and experienced an intricate evolution of life histories and feeding habits. Within Rhynchocephalia, only Pleurosauridae are thought to be marine and piscivorous. Here, we present bone histological data of the Jurassic pleurosaurid Palaeopleurosaurus, showing osteosclerosis (i.e. bone mass increase) in its gastralia, and some osteosclerosis in its rib but no increase in bone mass in the femur, supporting a gradual skeletal specialization for an aquatic way of life. Similar to Sphenodon, the bone tissue deposited in Palaeopleurosaurus is lamellar zonal bone. The femoral growth pattern in Palaeopleurosaurus differs from that of terrestrial Sphenodon in a more irregular spacing of growth marks and deposition of non-annual (i.e. non-continuous) rest lines, indicating strong dependency on exogenous factors. The annual growth mark count in adult but not yet fully grown Palaeopleurosaurus is much lower when compared to adult individuals of Sphenodon, which could indicate a lower lifespan for Palaeopleurosaurus. Whereas the gastral ribs of Palaeopleurosaurus and Sphenodon are similar in composition, the ribs of Sphenodon differ profoundly in being separated into a proximal tubular rib part with a thick cortex, and an elliptical, flared ventral part characterised by extremely thin cortical bone. The latter argues against a previously inferred protective function of the ventral rib parts for the vulnerable viscera in Sphenodon.

Immune defense and host life history.

PubMed

Zuk, Marlene; Stoehr, Andrew M

2002-10-01

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

Interpersonal violence, early life adversity, and suicidal behavior in hypersexual men.

PubMed

Chatzittofis, Andreas; Savard, Josephine; Arver, Stefan; Öberg, Katarina Görts; Hallberg, Jonas; Nordström, Peter; Jokinen, Jussi

2017-06-01

Background and aims There are significant gaps in knowledge regarding the role of childhood adversity, interpersonal violence, and suicidal behavior in hypersexual disorder (HD). The aim of this study was to investigate interpersonal violence in hypersexual men compared with healthy volunteers and the experience of violence in relation to suicidal behavior. Methods This case-control study includes 67 male patients with HD and 40 healthy male volunteers. The Childhood Trauma Questionnaire - Short Form (CTQ-SF) and the Karolinska Interpersonal Violence Scale (KIVS) were used for assessing early life adversity and interpersonal violence in childhood and in adult life. Suicidal behavior (attempts and ideation) was assessed with the Mini-International Neuropsychiatric Interview (version 6.0) and the Montgomery-Åsberg Depression Rating Scale - Self-rating. Results Hypersexual men reported more exposure to violence in childhood and more violent behavior as adults compared with healthy volunteers. Suicide attempters (n = 8, 12%) reported higher KIVS total score, more used violence as a child, more exposure to violence as an adult as well as higher score on CTQ-SF subscale measuring sexual abuse (SA) compared with hypersexual men without suicide attempt. Discussion Hypersexuality was associated with interpersonal violence with higher total scores in patients with a history of suicide attempt. The KIVS subscale exposure to interpersonal violence as a child was validated using the CTQ-SF but can be complemented with questions focusing on SA for full assessment of early life adversity. Conclusion Childhood adversity is an important factor in HD and interpersonal violence might be related to suicidal behavior in hypersexual men.

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

PubMed

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

2008-02-13

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

Life-history traits predict perennial species response to fire in a desert ecosystem

PubMed Central

Shryock, Daniel F; DeFalco, Lesley A; Esque, Todd C

2014-01-01

The Mojave Desert of North America has become fire-prone in recent decades due to invasive annual grasses that fuel wildfires following years of high rainfall. Perennial species are poorly adapted to fire in this system, and post-fire shifts in species composition have been substantial but variable across community types. To generalize across a range of conditions, we investigated whether simple life-history traits could predict how species responded to fire. Further, we classified species into plant functional types (PFTs) based on combinations of life-history traits and evaluated whether these groups exhibited a consistent fire-response. Six life-history traits varied significantly between burned and unburned areas in short (up to 4 years) or long-term (up to 52 years) post-fire datasets, including growth form, lifespan, seed size, seed dispersal, height, and leaf longevity. Forbs and grasses consistently increased in abundance after fire, while cacti were reduced and woody species exhibited a variable response. Woody species were classified into three PFTs based on combinations of life-history traits. Species in Group 1 increased in abundance after fire and were characterized by short lifespans, small, wind-dispersed seeds, low height, and deciduous leaves. Species in Group 2 were reduced by fire and distinguished from Group 1 by longer lifespans and evergreen leaves. Group 3 species, which also decreased after fire, were characterized by long lifespans, large non-wind dispersed seeds, and taller heights. Our results show that PFTs based on life-history traits can reliably predict the responses of most species to fire in the Mojave Desert. Dominant, long-lived species of this region possess a combination of traits limiting their ability to recover, presenting a clear example of how a novel disturbance regime may shift selective environmental pressures to favor alternative life-history strategies. PMID:25247062

Life-history traits predict perennial species response to fire in a desert ecosystem

USGS Publications Warehouse

Shryock, Daniel F.; DeFalco, Lesley A.; Esque, Todd C.

2014-01-01

The Mojave Desert of North America has become fire-prone in recent decades due to invasive annual grasses that fuel wildfires following years of high rainfall. Perennial species are poorly adapted to fire in this system, and post-fire shifts in species composition have been substantial but variable across community types. To generalize across a range of conditions, we investigated whether simple life-history traits could predict how species responded to fire. Further, we classified species into plant functional types (PFTs) based on combinations of life-history traits and evaluated whether these groups exhibited a consistent fire-response. Six life-history traits varied significantly between burned and unburned areas in short (up to 4 years) or long-term (up to 52 years) post-fire datasets, including growth form, lifespan, seed size, seed dispersal, height, and leaf longevity. Forbs and grasses consistently increased in abundance after fire, while cacti were reduced and woody species exhibited a variable response. Woody species were classified into three PFTs based on combinations of life-history traits. Species in Group 1 increased in abundance after fire and were characterized by short lifespans, small, wind-dispersed seeds, low height, and deciduous leaves. Species in Group 2 were reduced by fire and distinguished from Group 1 by longer lifespans and evergreen leaves. Group 3 species, which also decreased after fire, were characterized by long lifespans, large non-wind dispersed seeds, and taller heights. Our results show that PFTs based on life-history traits can reliably predict the responses of most species to fire in the Mojave Desert. Dominant, long-lived species of this region possess a combination of traits limiting their ability to recover, presenting a clear example of how a novel disturbance regime may shift selective environmental pressures to favor alternative life-history strategies.

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…

Life history theory and dental development in four species of catarrhine primates.

PubMed

Dirks, Wendy; Bowman, Jacqui E

2007-09-01

Dental development was reconstructed in several individuals representing four species of catarrhine primates--Symphalangus syndactylus, Hylobates lar, Semnopithecus entellus priam, and Papio hamadryas--using the techniques of dental histology. Bar charts assumed to represent species-typical dental development were constructed from these data and estimated ages at first and third molar emergence were plotted on them along with ages at weaning, menarche, and first reproduction from the literature. The estimated age at first molar emergence appears to occur at weaning in the siamang, lar gibbon, and langur, and just after weaning in the baboon. Age at menarche and first reproduction occur earlier relative to dental development in both cercopithecoids than in the hylobatids, suggesting that early reproduction may be a derived trait in cercopithecoids. The results are examined in the context of life history theory.

Chemically-mediated interactions between macroalgae Dictyota spp. and multiple life-history stages of the coral Porites astreoides

USGS Publications Warehouse

Paul, Valerie J.; Kuffner, Ilsa B.; Walters, Linda J.; Ritson-Williams, Raphael; Beach, Kevin S.; Becerro, Mikel A.

2011-01-01

Competition between corals and macroalgae is often assumed to occur on reefs, especially those that have undergone shifts from coral to algal dominance; however, data examining these competitive interactions, especially during the early life-history stages of corals, are scarce. We conducted a series of field and outdoor seawater-table experiments to test the hypothesis that allelopathy (chemical inhibition) mediates interactions between 2 common brown macroalgae, Dictyota pulchella and D. pinnatifida, and the coral Porites astreoides at different life-history stages of the coral. D. pinnatifida significantly reduced larval survival and larval recruitment. The extracts of both D. pinnatifida and D. pulchella significantly reduced larval survival, and the extract of D. pulchella also negatively influenced larval recruitment. There was no measurable effect of the crude extracts from Dictyota spp. on the photophysiology of adult corals. Our results provide evidence that these Dictyota species chemically compete with P. astreoides by negatively affecting larval settlement and recruitment as well as the survival of larvae and new recruits. Macroalgae may perpetuate their dominance on degraded reefs by chemically inhibiting the process of coral recruitment.

The Invention and Early History of the N-Localizer for Stereotactic Neurosurgery

PubMed Central

Nelson, James A

2016-01-01

Nearly four decades after the invention of the N-localizer, its origin and history remain misunderstood. Some are unaware that a third-year medical student invented this technology. The following conspectus accurately chronicles the origin of the N-localizer, presents recently discovered evidence that documents its history, and corrects misconceptions related to its origin and early history. PMID:27462476

Early history of Neanderthals and Denisovans

PubMed Central

Bohlender, Ryan J.; Huff, Chad D.

2017-01-01

Extensive DNA sequence data have made it possible to reconstruct human evolutionary history in unprecedented detail. We introduce a method to study the past several hundred thousand years. Our results show that (i) the Neanderthal–Denisovan lineage declined to a small size just after separating from the modern lineage, (ii) Neanderthals and Denisovans separated soon thereafter, and (iii) the subsequent Neanderthal population was large and deeply subdivided. They also (iv) support previous estimates of gene flow from Neanderthals into modern Eurasians. These results suggest an archaic human diaspora early in the Middle Pleistocene. PMID:28784789

Cerebrospinal fluid corticotropin-releasing factor and perceived early-life stress in depressed patients and healthy control subjects.

PubMed

Carpenter, Linda L; Tyrka, Audrey R; McDougle, Christopher J; Malison, Robert T; Owens, Michael J; Nemeroff, Charles B; Price, Lawrence H

2004-04-01

Previous studies have reported elevated concentrations of cerebrospinal fluid (CSF) corticotropin-releasing factor (CRF) in patients with major depression. Elevations of CSF CRF have also been reported in adult laboratory animals exposed to the stress of brief maternal deprivation or maternal neglect in the neonatal or preweaning period. The present study was designed to determine whether major depression and a history of perceived early adversity in childhood are independently associated with elevated CSF CRF concentrations in adults. In this case-control study, 27 medication-free adults with major depression and 25 matched controls underwent standardized lumbar puncture for collection of a single CSF sample at 1200. Subjects provided data about significant adverse early-life experiences and rated their global perceived level of stress during pre-school and preteen years on a six-point Likert scale. The mean difference in CSF CRF between depressed patients and controls did not reach statistical significance. In a regression model, perceived early-life stress was a significant predictor of CSF CRF, but depression was not. Perinatal adversity and perceived adversity in the preteen adversity years (ages 6-13 years) were both independently associated with decreasing CSF CRF concentrations. The relationship observed between perceived early-life stress and adult CSF CRF concentrations in this study closely parallels recent preclinical findings. More work is needed to elucidate the critical nature and timing of early events that may be associated with enduring neuroendocrine changes in humans.

Accounting Early for Life Long Learning: The AcE Project.

ERIC Educational Resources Information Center

University Coll. Worcester (England). Centre for Research in Early Childhood Education.

Building upon the work of the Effective Early Learning (EEL) Project in raising the quality of early learning for young children in the United Kingdom, the 3-year Accounting Early for Life Long Learning Project (AcE Project) focuses on enhancing in 3- to 6-year-olds those attitudes and dispositions that are important to life-long learning. This…

Earth's early biosphere

NASA Technical Reports Server (NTRS)

Des Marais, D. J.

1998-01-01

Understanding our own early biosphere is essential to our search for life elsewhere, because life arose on Earth very early and rocky planets shared similar early histories. The biosphere arose before 3.8 Ga ago, was exclusively unicellular and was dominated by hyperthermophiles that utilized chemical sources of energy and employed a range of metabolic pathways for CO2 assimilation. Photosynthesis also arose very early. Oxygenic photosynthesis arose later but still prior to 2.7 Ga. The transition toward the modern global environment was paced by a decline in volcanic and hydrothermal activity. These developments allowed atmospheric O2 levels to increase. The O2 increase created new niches for aerobic life, most notably the more advanced Eukarya that eventually spawned the megascopic fauna and flora of our modern biosphere.

Fragmentation and Unpredictability of Early-Life Experience in Mental Disorders

PubMed Central

Baram, Tallie Z.; Solodkin, Ana; Davis, Elysia P.; Stern, Hal; Obenaus, Andre; Sandman, Curt A.; Small, Steven L.

2012-01-01

Maternal sensory signals in early life play a crucial role in programming the structure and function of the developing brain, promoting vulnerability or resilience to emotional and cognitive disorders. In rodent models of early-life stress, fragmentation and unpredictability of maternally derived sensory signals provoke persistent cognitive and emotional dysfunction in offspring. Similar variability and inconsistency of maternal signals during both gestation and early postnatal human life may influence development of emotional and cognitive functions, including those that underlie later depression and anxiety. PMID:22885631

Smell, learn and live: the role of chemical alarm cues in predator learning during early life history in a marine fish.

PubMed

Holmes, Thomas H; McCormick, Mark I

2010-03-01

The speed with which individuals can learn to identify and react appropriately to predation threats when transitioning to new life history stages and habitats will influence their survival. This study investigated the role of chemical alarm cues in both anti-predator responses and predator identification during a transitional period in a newly settled coral reef damselfish, Pomacentrus amboinensis. Individuals were tested for changes in seven behavioural traits in response to conspecific and heterospecific skin extracts. Additionally, we tested whether fish could learn to associate a previously novel chemical cue (i.e. simulated predator scent) with danger, after previously being exposed to a paired cue combining the conspecific skin extract with the novel scent. Fish exposed to conspecific skin extracts were found to significantly decreased their feeding rate whilst those exposed to heterospecific and control cues showed no change. Individuals were also able to associate a previously novel scent with danger after only a single previous exposure to the paired conspecific skin extract/novel scent cue. Our results indicate that chemical alarm cues play a large role in both threat detection and learned predator recognition during the early post-settlement period in coral reef fishes. Copyright (c) 2010. Published by Elsevier B.V.

Diagnosing the dangerous demography of manta rays using life history theory.

PubMed

Dulvy, Nicholas K; Pardo, Sebastián A; Simpfendorfer, Colin A; Carlson, John K

2014-01-01

Background. The directed harvest and global trade in the gill plates of mantas, and devil rays, has led to increased fishing pressure and steep population declines in some locations. The slow life history, particularly of the manta rays, is cited as a key reason why such species have little capacity to withstand directed fisheries. Here, we place their life history and demography within the context of other sharks and rays. Methods. Despite the limited availability of data, we use life history theory and comparative analysis to estimate the intrinsic risk of extinction (as indexed by the maximum intrinsic rate of population increase r max) for a typical generic manta ray using a variant of the classic Euler-Lotka demographic model. This model requires only three traits to calculate the maximum intrinsic population growth rate r max: von Bertalanffy growth rate, annual pup production and age at maturity. To account for the uncertainty in life history parameters, we created plausible parameter ranges and propagate these uncertainties through the model to calculate a distribution of the plausible range of r max values. Results. The maximum population growth rate r max of manta ray is most sensitive to the length of the reproductive cycle, and the median r max of 0.116 year(-1) 95th percentile [0.089-0.139] is one of the lowest known of the 106 sharks and rays for which we have comparable demographic information. Discussion. In common with other unprotected, unmanaged, high-value large-bodied sharks and rays the combination of very low population growth rates of manta rays, combined with the high value of their gill rakers and the international nature of trade, is highly likely to lead to rapid depletion and potential local extinction unless a rapid conservation management response occurs worldwide. Furthermore, we show that it is possible to derive important insights into the demography extinction risk of data-poor species using well-established life history theory.

Diagnosing the dangerous demography of manta rays using life history theory

PubMed Central

Pardo, Sebastián A.; Simpfendorfer, Colin A.; Carlson, John K.

2014-01-01

Background. The directed harvest and global trade in the gill plates of mantas, and devil rays, has led to increased fishing pressure and steep population declines in some locations. The slow life history, particularly of the manta rays, is cited as a key reason why such species have little capacity to withstand directed fisheries. Here, we place their life history and demography within the context of other sharks and rays. Methods. Despite the limited availability of data, we use life history theory and comparative analysis to estimate the intrinsic risk of extinction (as indexed by the maximum intrinsic rate of population increase rmax) for a typical generic manta ray using a variant of the classic Euler–Lotka demographic model. This model requires only three traits to calculate the maximum intrinsic population growth rate rmax: von Bertalanffy growth rate, annual pup production and age at maturity. To account for the uncertainty in life history parameters, we created plausible parameter ranges and propagate these uncertainties through the model to calculate a distribution of the plausible range of rmax values. Results. The maximum population growth rate rmax of manta ray is most sensitive to the length of the reproductive cycle, and the median rmax of 0.116 year−1 95th percentile [0.089–0.139] is one of the lowest known of the 106 sharks and rays for which we have comparable demographic information. Discussion. In common with other unprotected, unmanaged, high-value large-bodied sharks and rays the combination of very low population growth rates of manta rays, combined with the high value of their gill rakers and the international nature of trade, is highly likely to lead to rapid depletion and potential local extinction unless a rapid conservation management response occurs worldwide. Furthermore, we show that it is possible to derive important insights into the demography extinction risk of data-poor species using well-established life history theory

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

Effect of Early- and Adult-Life Socioeconomic Circumstances on Physical Inactivity.

PubMed

Cheval, Boris; Sieber, Stefan; Guessous, Idris; Orsholits, Dan; Courvoisier, Delphine S; Kliegel, Matthias; Stringhini, Silvia; Swinnen, Stephan P; Burton-Jeangros, Claudine; Cullati, Stéphane; Boisgontier, Matthieu P

2018-03-01

This study aimed to investigate the associations between early- and adult-life socioeconomic circumstances and physical inactivity (level and evolution) in aging using large-scale longitudinal data. This study used the Survey of Health Ageing and Retirement in Europe, a 10-yr population-based cohort study with repeated measurements in five waves, every 2 yr between 2004 and 2013. Self-reported physical inactivity (waves 1, 2, 4, and 5), household income (waves 1, 2, 4, and 5), educational attainment (wave of the first measurement occasion), and early-life socioeconomic circumstance (wave 3) were collected in 22,846 individuals 50 to 95 yr of age. Risk of physical inactivity was increased for women with the most disadvantaged early-life socioeconomic circumstances (odds ratio [OR], 1.49; 95% confidence interval [CI], 1.20-1.86). With aging, the risk of physical inactivity increased for both sexes and was strongest for those with the most disadvantaged early-life socioeconomic circumstances (OR, 1.04 (95% CI, 1.02-1.06) for women; OR, 1.02 (95% CI, 1.00-1.05) for men), with the former effect being more robust than the latter one. The association between early-life socioeconomic circumstances and physical inactivity was mediated by adult-life socioeconomic circumstances, with education being the strongest mediator. Early-life socioeconomic circumstances predicted high levels of physical inactivity at older ages, but this effect was mediated by socioeconomic indicators in adult life. This finding has implications for public health policies, which should continue to promote education to reduce physical inactivity in people at older ages and to ensure optimal healthy aging trajectories, especially among women with disadvantaged early-life socioeconomic circumstances.

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…

Putting all your eggs in one basket: life-history strategies, bet hedging, and diversification.

PubMed

White, Andrew Edward; Li, Yexin Jessica; Griskevicius, Vladas; Neuberg, Steven L; Kenrick, Douglas T

2013-05-01

Diversification of resources is a strategy found everywhere from the level of microorganisms to that of giant Wall Street investment firms. We examine the functional nature of diversification using life-history theory-a framework for understanding how organisms navigate resource-allocation trade-offs. This framework suggests that diversification may be adaptive or maladaptive depending on one's life-history strategy and that these differences should be observed under conditions of threat. In three studies, we found that cues of mortality threat interact with one index of life-history strategy, childhood socioeconomic status (SES), to affect diversification. Among those from low-SES backgrounds, mortality threat increased preferences for diversification. However, among those from high-SES backgrounds, mortality threat had the opposite effect, inclining people to put all their eggs in one basket. The same interaction pattern emerged with a potential biomarker of life-history strategy, oxidative stress. These findings highlight when, and for whom, different diversification strategies can be advantageous.

Influence of early life exposure, host genetics and diet on the mouse gut microbiome and metabolome

DOE Office of Scientific and Technical Information (OSTI.GOV)

Snijders, Antoine M.; Langley, Sasha A.; Kim, Young-Mo

Although the gut microbiome plays important roles in host physiology, health and disease1, we lack understanding of the complex interplay between host genetics and early life environment on the microbial and metabolic composition of the gut.We used the genetically diverse Collaborative Cross mouse system2 to discover that early life history impacts themicrobiome composition, whereas dietary changes have only a moderate effect. By contrast, the gut metabolome was shaped mostly by diet, with specific non-dietary metabolites explained by microbial metabolism. Quantitative trait analysis identified mouse genetic trait loci (QTL) that impact the abundances of specific microbes. Human orthologues of genes inmore » the mouse QTL are implicated in gastrointestinal cancer. Additionally, genes located in mouse QTL for Lactobacillales abundance are implicated in arthritis, rheumatic disease and diabetes. Furthermore, Lactobacillales abundance was predictive of higher host T-helper cell counts, suggesting an important link between Lactobacillales and host adaptive immunity.« less

Relationship between employment histories and frailty trajectories in later life: evidence from the English Longitudinal Study of Ageing

PubMed Central

Lu, Wentian; Benson, Rebecca; Glaser, Karen; Corna, Laurie M; Worts, Diana; McDonough, Peggy; Price, Debora; Sacker, Amanda

2017-01-01

Background Given the acceleration of population ageing and policy changes to extend working lives, evidence is needed on the ability of older adults to work for longer. To understand more about the health impacts of work, this study examined the relationship between employment histories before retirement and trajectories of frailty thereafter. Methods The sample comprised 2765 women and 1621 men from the English Longitudinal Study of Ageing. We used gendered typologies of life-time employment and a frailty index (FI). Multilevel growth curve models were used to predict frailty trajectories by employment histories. Results Women who had a short break for family care, then did part-time work till 59 years had a lower FI after 60 years than those who undertook full-time work until 59 years. Women who were largely family carers or non-employed throughout adulthood, had higher levels of frailty at 60 years but experienced a slower decline with age. Men who worked full-time but early exited at either 49 or 60 years had a higher FI at 65 years than those who worked full-time up to 65 years. Interaction between employment histories and age indicated that men in full-time work who experienced an early exit at 49 tended to report slower declines. Conclusions For women, experiencing distinct periods throughout the lifecourse of either work or family care may be advantageous for lessening frailty risk in later life. For men, leaving paid employment before 65 years seems to be beneficial for decelerating increases in frailty thereafter. Continuous full-time work until retirement age conferred no long-term health benefits. PMID:27913614

Development of the Life Story in Early Adolescence

ERIC Educational Resources Information Center

Steiner, Kristina L.; Pillemer, David B.

2018-01-01

Life span developmental psychology proposes that the ability to create a coherent life narrative does not develop until early adolescence. Using a novel methodology, 10-, 12-, and 14-year-old participants were asked to tell their life stories aloud to a researcher. Later, participants separated their transcribed narratives into self-identified…

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. © 2014 The Author(s). Evolution © 2014 The Society for the Study of Evolution.

Fine scale relationships between sex, life history, and dispersal of masu salmon

USGS Publications Warehouse

Kitanishi, Shigeru; Yamamoto, Toshiaki; Koizumi, Itsuro; Dunham, Jason B.; Higashi, Seigo

2012-01-01

Identifying the patterns and processes driving dispersal is critical for understanding population structure and dynamics. In many organisms, sex-biased dispersal is related to the type of mating system. Considerably less is known about the influence of life history variability on dispersal. Here we investigated patterns of dispersal in masu salmon (Oncorhynchus masou) to evaluate influences of sex and life history on dispersal. As expected, assignment tests and isolation by distance analysis revealed that dispersal of marine-migratory masu salmon was male-biased. However, dispersal of resident and migratory males did not follow our expectation and marine-migratory individuals dispersed more than residents. This may be because direct competition between marine-migratory and resident males is weak or that the cost of dispersal is smaller for marine-migratory individuals. This study revealed that both sex and migratory life history influence patterns of dispersal at a local scale in masu salmon.

Early-life Origins of Lifecycle Well-being: Research and Policy Implications

PubMed Central

Currie, Janet; Rossin-Slater, Maya

2016-01-01

Mounting evidence across different disciplines suggests that early-life conditions can have consequences on individual outcomes throughout the lifecycle. Relative to other developed countries, the United States fares poorly on standard indicators of early-life health, and this disadvantage may have profound consequences not only for population well-being, but also for economic growth and competitiveness in a global economy. In this paper, we first discuss the research on the strength of the link between early-life health and adult outcomes, and then provide an evidence-based review of the effectiveness of existing U.S. policies targeting the early-life environment. We conclude that there is a robust and economically meaningful relationship between early-life conditions and well-being throughout the lifecycle, as measured by adult health, educational attainment, labor market attachment, and other indicators of socio-economic status. However, there is some variation in the degree to which current policies in the U.S. are effective in improving early-life conditions. Among existing programs, some of the most effective are the Special Supplemental Program for Women, Infants, and Children (WIC), home visiting with nurse practitioners, and high-quality, center-based early childhood care and education. In contrast, the evidence on other policies such as prenatal care and family leave is more mixed and limited. PMID:25558491

Fishing-induced life-history changes degrade and destabilize harvested ecosystems.

PubMed

Kuparinen, Anna; Boit, Alice; Valdovinos, Fernanda S; Lassaux, Hélène; Martinez, Neo D

2016-02-26

Fishing is widely known to magnify fluctuations in targeted populations. These fluctuations are correlated with population shifts towards young, small, and more quickly maturing individuals. However, the existence and nature of the mechanistic basis for these correlations and their potential ecosystem impacts remain highly uncertain. Here, we elucidate this basis and associated impacts by showing how fishing can increase fluctuations in fishes and their ecosystem, particularly when coupled with decreasing body sizes and advancing maturation characteristic of the life-history changes induced by fishing. More specifically, using an empirically parameterized network model of a well-studied lake ecosystem, we show how fishing may both increase fluctuations in fish abundances and also, when accompanied by decreasing body size of adults, further decrease fish abundance and increase temporal variability of fishes' food resources and their ecosystem. In contrast, advanced maturation has relatively little effect except to increase variability in juvenile populations. Our findings illustrate how different mechanisms underlying life-history changes that may arise as evolutionary responses to intensive, size-selective fishing can rapidly and continuously destabilize and degrade ecosystems even after fishing has ceased. This research helps better predict how life-history changes may reduce fishes' resilience to fishing and ecosystems' resistance to environmental variations.

Fishing-induced life-history changes degrade and destabilize harvested ecosystems

NASA Astrophysics Data System (ADS)

Kuparinen, Anna; Boit, Alice; Valdovinos, Fernanda S.; Lassaux, Hélène; Martinez, Neo D.

2016-02-01

Fishing is widely known to magnify fluctuations in targeted populations. These fluctuations are correlated with population shifts towards young, small, and more quickly maturing individuals. However, the existence and nature of the mechanistic basis for these correlations and their potential ecosystem impacts remain highly uncertain. Here, we elucidate this basis and associated impacts by showing how fishing can increase fluctuations in fishes and their ecosystem, particularly when coupled with decreasing body sizes and advancing maturation characteristic of the life-history changes induced by fishing. More specifically, using an empirically parameterized network model of a well-studied lake ecosystem, we show how fishing may both increase fluctuations in fish abundances and also, when accompanied by decreasing body size of adults, further decrease fish abundance and increase temporal variability of fishes’ food resources and their ecosystem. In contrast, advanced maturation has relatively little effect except to increase variability in juvenile populations. Our findings illustrate how different mechanisms underlying life-history changes that may arise as evolutionary responses to intensive, size-selective fishing can rapidly and continuously destabilize and degrade ecosystems even after fishing has ceased. This research helps better predict how life-history changes may reduce fishes’ resilience to fishing and ecosystems’ resistance to environmental variations.

Responses to a warming world: Integrating life history, immune investment, and pathogen resistance in a model insect species.

PubMed

Laughton, Alice M; O'Connor, Cian O; Knell, Robert J

2017-11-01

Environmental temperature has important effects on the physiology and life history of ectothermic animals, including investment in the immune system and the infectious capacity of pathogens. Numerous studies have examined individual components of these complex systems, but little is known about how they integrate when animals are exposed to different temperatures. Here, we use the Indian meal moth ( Plodia interpunctella ) to understand how immune investment and disease resistance react and potentially trade-off with other life-history traits. We recorded life-history (development time, survival, fecundity, and body size) and immunity (hemocyte counts, phenoloxidase activity) measures and tested resistance to bacterial ( E. coli ) and viral ( Plodia interpunctella granulosis virus) infection at five temperatures (20-30°C). While development time, lifespan, and size decreased with temperature as expected, moths exhibited different reproductive strategies in response to small changes in temperature. At cooler temperatures, oviposition rates were low but tended to increase toward the end of life, whereas warmer temperatures promoted initially high oviposition rates that rapidly declined after the first few days of adult life. Although warmer temperatures were associated with strong investment in early reproduction, there was no evidence of an associated trade-off with immune investment. Phenoloxidase activity increased most at cooler temperatures before plateauing, while hemocyte counts increased linearly with temperature. Resistance to bacterial challenge displayed a complex pattern, whereas survival after a viral challenge increased with rearing temperature. These results demonstrate that different immune system components and different pathogens can respond in distinct ways to changes in temperature. Overall, these data highlight the scope for significant changes in immunity, disease resistance, and host-parasite population dynamics to arise from small

The habitat and nature of early life.

PubMed

Nisbet, E G; Sleep, N H

2001-02-22

Earth is over 4,500 million years old. Massive bombardment of the planet took place for the first 500-700 million years, and the largest impacts would have been capable of sterilizing the planet. Probably until 4,000 million years ago or later, occasional impacts might have heated the ocean over 100 degrees C. Life on Earth dates from before about 3,800 million years ago, and is likely to have gone through one or more hot-ocean 'bottlenecks'. Only hyperthermophiles (organisms optimally living in water at 80-110 degrees C) would have survived. It is possible that early life diversified near hydrothermal vents, but hypotheses that life first occupied other pre-bottleneck habitats are tenable (including transfer from Mars on ejecta from impacts there). Early hyperthermophile life, probably near hydrothermal systems, may have been non-photosynthetic, and many housekeeping proteins and biochemical processes may have an original hydrothermal heritage. The development of anoxygenic and then oxygenic photosynthesis would have allowed life to escape the hydrothermal setting. By about 3,500 million years ago, most of the principal biochemical pathways that sustain the modern biosphere had evolved, and were global in scope.

The conservation and management of tunas and their relatives: setting life history research priorities.

PubMed

Juan-Jordá, Maria José; Mosqueira, Iago; Freire, Juan; Dulvy, Nicholas K

2013-01-01

Scombrids (tunas, bonitos, Spanish mackerels and mackerels) support important fisheries in tropical, subtropical and temperate waters around the world, being one of the most economically- and socially-important marine species globally. Their sustainable exploitation, management and conservation depend on accurate life history information for the development of quantitative fisheries stock assessments, and in the fishery data-poor situations for the identification of vulnerable species. Here, we assemble life history traits (maximum size, growth, longevity, maturity, fecundity, spawning duration and spawning interval) for the 51 species of scombrids globally. We identify major biological gaps in knowledge and prioritize life history research needs in scombrids based on their biological gaps in knowledge, the importance of their fisheries and their current conservation status according to the International Union for Conservation of Nature Red List. We find that the growth and reproductive biology of tunas and mackerel species have been more extensively studied than for Spanish mackerels and bonitos, although there are notable exceptions in all groups. We also reveal that reproductive biology of species, particular fecundity, is the least studied biological aspect in scombrids. We identify two priority groups, including 32 species of scombrids, and several populations of principal market tunas, for which life history research should be prioritized following the species-specific life history gaps identified in this study in the coming decades. By highlighting the important gaps in biological knowledge and providing a priority setting for life history research in scombrid species this study provides guidance for management and conservation and serves as a guide for biologists and resource managers interested in the biology, ecology, and management of scombrid species.

The Conservation and Management of Tunas and Their Relatives: Setting Life History Research Priorities

PubMed Central

Juan-Jordá, Maria José; Mosqueira, Iago; Freire, Juan; Dulvy, Nicholas K.

2013-01-01

Scombrids (tunas, bonitos, Spanish mackerels and mackerels) support important fisheries in tropical, subtropical and temperate waters around the world, being one of the most economically- and socially-important marine species globally. Their sustainable exploitation, management and conservation depend on accurate life history information for the development of quantitative fisheries stock assessments, and in the fishery data-poor situations for the identification of vulnerable species. Here, we assemble life history traits (maximum size, growth, longevity, maturity, fecundity, spawning duration and spawning interval) for the 51 species of scombrids globally. We identify major biological gaps in knowledge and prioritize life history research needs in scombrids based on their biological gaps in knowledge, the importance of their fisheries and their current conservation status according to the International Union for Conservation of Nature Red List. We find that the growth and reproductive biology of tunas and mackerel species have been more extensively studied than for Spanish mackerels and bonitos, although there are notable exceptions in all groups. We also reveal that reproductive biology of species, particular fecundity, is the least studied biological aspect in scombrids. We identify two priority groups, including 32 species of scombrids, and several populations of principal market tunas, for which life history research should be prioritized following the species-specific life history gaps identified in this study in the coming decades. By highlighting the important gaps in biological knowledge and providing a priority setting for life history research in scombrid species this study provides guidance for management and conservation and serves as a guide for biologists and resource managers interested in the biology, ecology, and management of scombrid species. PMID:23950930

Evolution of dispersal and life history strategies – Tetrahymena ciliates

PubMed Central

Fjerdingstad, Else J; Schtickzelle, Nicolas; Manhes, Pauline; Gutierrez, Arnaud; Clobert, Jean

2007-01-01

Background Considerable attention has focused on how selection on dispersal and other core life-history strategies (reproductive effort, survival ability, colonization capacity) may lead to so-called dispersal syndromes. Studies on genetic variation in these syndromes within species could importantly increase our understanding of their evolution, by revealing whether traits co-vary across genetic lineages in the manner predicted by theoretical models, and by stimulating further hypotheses for experimental testing. Yet such studies remain scarce. Here we studied the ciliated protist Tetrahymena thermophila, a particularly interesting organism due to cells being able to transform into morphs differing dramatically in swim-speed. We investigated dispersal, morphological responses, reproductive performance, and survival in ten different clonal strains. Then, we examined whether life history traits co-varied in the manner classically predicted for ruderal species, examined the investment of different strains into short- and putative long-distance dispersal, while considering also the likely impact of semi-sociality (cell aggregation, secretion of 'growth factors') on dispersal strategies. Results Very significant among-strain differences were found with regard to dispersal rate, morphological commitment and plasticity, and almost all core life-history traits (e.g. survival, growth performance and strategy), with most of these traits being significantly intercorrelated. Some strains showed high short-distance dispersal rates, high colonization capacity, bigger cell size, elevated growth performance, and good survival abilities. These well performing strains, however, produced fewer fast-swimming dispersal morphs when subjected to environmental degradation than did philopatric strains performing poorly under normal conditions. Conclusion Strong evidence was found for a genetic covariation between dispersal strategies and core life history traits in T. thermophila, with a

Potential effects of changes in temperature and food resources on life history trajectories of juvenile Oncorhynchus mykiss

USGS Publications Warehouse

Benjamin, Joseph R.; Connolly, Patrick J.; Romine, Jason G.; Perry, Russell W.

2013-01-01

Increasing temperatures and changes in food resources owing to climate change may alter the growth and migratory behavior of organisms. This is particularly important for salmonid species like Oncorhynchus mykiss, where some individuals remain in freshwater to mature (nonanadromous Rainbow Trout) and others migrate to sea (anadromous Steelhead). Whether one strategy is adopted over the other may depend on the individual's growth and size. In this study, we explored (1) how water temperature in Beaver Creek, a tributary to the Methow River, Washington, may increase under four climate scenarios, (2) how these thermal changes may alter the life history trajectory followed by O. mykiss (i.e., when and if to smolt), and (3) how changes in food quality or quantity might interact with increasing temperatures. We combined bioenergetic and state-dependent life history models parameterized for O. mykiss in Beaver Creek to mimic baseline life history trajectories. Based on our simulations, when mean water temperature was increased by 0.6°C there was a reduction in life history diversity and a 57% increase in the number of individuals becoming smolts. When mean temperature was increased by 2.7°C, it resulted in 87% fewer smolts than in the baseline and fewer life history trajectories expressed. A reduction in food resources led to slower growth, more life history trajectories, and a greater proportion of smolts. In contrast, when food resources were increased, fish grew faster, which reduced the proportion of smolts and life history diversity. Our modeling suggests that warmer water temperatures associated with climate change could decrease the life history diversity of O. mykiss in the central portion of their range and thereby reduce resiliency to other disturbances. In addition, changes in food resources could mediate or exacerbate the effect of water temperature on the life history trajectories of O. mykiss.

Early-Life Stress, HPA Axis Adaptation, and Mechanisms Contributing to Later Health Outcomes

PubMed Central

Maniam, Jayanthi; Antoniadis, Christopher; Morris, Margaret J.

2014-01-01

Stress activates the hypothalamic–pituitary–adrenal (HPA) axis, which then modulates the degree of adaptation and response to a later stressor. It is known that early-life stress can impact on later health but less is known about how early-life stress impairs HPA axis activity, contributing to maladaptation of the stress–response system. Early-life stress exposure (either prenatally or in the early postnatal period) can impact developmental pathways resulting in lasting structural and regulatory changes that predispose to adulthood disease. Epidemiological, clinical, and experimental studies have demonstrated that early-life stress produces long term hyper-responsiveness to stress with exaggerated circulating glucocorticoids, and enhanced anxiety and depression-like behaviors. Recently, evidence has emerged on early-life stress-induced metabolic derangements, for example hyperinsulinemia and altered insulin sensitivity on exposure to a high energy diet later in life. This draws our attention to the contribution of later environment to disease vulnerability. Early-life stress can alter the expression of genes in peripheral tissues, such as the glucocorticoid receptor and 11-beta hydroxysteroid dehydrogenase (11β-HSD1). We propose that interactions between altered HPA axis activity and liver 11β-HSD1 modulates both tissue and circulating glucocorticoid availability, with adverse metabolic consequences. This review discusses the potential mechanisms underlying early-life stress-induced maladaptation of the HPA axis, and its subsequent effects on energy utilization and expenditure. The effects of positive later environments as a means of ameliorating early-life stress-induced health deficits, and proposed mechanisms underpinning the interaction between early-life stress and subsequent detrimental environmental exposures on metabolic risk will be outlined. Limitations in current methodology linking early-life stress and later health outcomes will also be

Growth and life history variability of the grey reef shark (Carcharhinus amblyrhynchos) across its range.

PubMed

Bradley, Darcy; Conklin, Eric; Papastamatiou, Yannis P; McCauley, Douglas J; Pollock, Kydd; Kendall, Bruce E; Gaines, Steven D; Caselle, Jennifer E

2017-01-01

For broadly distributed, often overexploited species such as elasmobranchs (sharks and rays), conservation management would benefit from understanding how life history traits change in response to local environmental and ecological factors. However, fishing obfuscates this objective by causing complex and often mixed effects on the life histories of target species. Disentangling the many drivers of life history variability requires knowledge of elasmobranch populations in the absence of fishing, which is rarely available. Here, we describe the growth, maximum size, sex ratios, size at maturity, and offer a direct estimate of survival of an unfished population of grey reef sharks (Carcharhinus amblyrhynchos) using data from an eight year tag-recapture study. We then synthesized published information on the life history of C. amblyrhynchos from across its geographic range, and for the first time, we attempted to disentangle the contribution of fishing from geographic variation in an elasmobranch species. For Palmyra's unfished C. amblyrhynchos population, the von Bertalanffy growth function (VBGF) growth coefficient k was 0.05 and asymptotic length L∞ was 163.3 cm total length (TL). Maximum size was 175.5 cm TL from a female shark, length at maturity was estimated at 116.7-123.2 cm TL for male sharks, maximum lifespan estimated from VBGF parameters was 18.1 years for both sexes combined, and annual survival was 0.74 year-1. Consistent with findings from studies on other elasmobranch species, we found significant intraspecific variability in reported life history traits of C. amblyrhynchos. However, contrary to what others have reported, we did not find consistent patterns in life history variability as a function of biogeography or fishing. Ultimately, the substantial, but not yet predictable variability in life history traits observed for C. amblyrhynchos across its geographic range suggests that regional management may be necessary to set sustainable harvest

Old world versus new world: life-history alterations in a successful invader introduced across Europe.

PubMed

Fox, Michael G; Copp, Gordon H

2014-02-01

We examined differences in pumpkinseed (Lepomis gibbosus) life-history traits between native North American and introduced European populations, and tested three life-history predictions related to the effect of temperature, growth, waterbody size, and the presence/absence of predators on native and non-native populations. Pumpkinseed populations exhibit more 'opportunistic' traits (earlier maturity, smaller size at maturity, and higher reproductive allocation) in their introduced European range than those in their native range. Predictions of life-history traits were improved when indicators of juvenile growth rate (mean length at age 2), waterbody size (surface area), and thermal regime (air temperature degree-days above 10 °C) were incorporated into models along with continental location, but European pumpkinseed populations exhibit more opportunistic life-history traits than North American populations even when these factors are accounted for. Native pumpkinseed in waterbodies containing piscivores mature later and at a larger size, and have lower gonadosomatic indices than those in waterbodies lacking piscivores, whereas there is no significant difference in the same three life-history traits between European waterbodies containing or lacking piscivores. Because congeneric competitors of the pumpkinseed are absent from Europe, the apparent absence of a predator life-history effect there could also be due to the absence of the major sunfish competitors. In either case, the evolution and maintenance of more opportunistic traits in European pumpkinseed can likely be attributed to enemy release, and this may explain the successful establishment and spread of pumpkinseed in many parts of Europe.

Early traumatic life events, parental attitudes, family history, and birth risk factors in patients with depressive disorder and healthy controls.

PubMed

Bandelow, Borwin; Gutermann, Julia; Peter, Helmut; Wedekind, Dirk

2013-02-01

Only few studies have compared the frequency of traumatic life events during childhood in inpatients with depression with a healthy control group. Consecutively admitted inpatients with depression (n = 79), most of whom belonged to the melancholic subtype (n = 73; 92.4%), and healthy controls (n = 110) were investigated using a comprehensive retrospective interview with 203 questions regarding childhood traumatic life events, parental attitudes, family history of psychiatric disorders and birth risk factors. Depressed patients had significantly more severe traumatic events (mean score 1.33; SD 1.4) than control subjects (0.85; SD 1.2) on a 0-10 point "severe trauma scale". 70.9% (n = 56) of the depressed patients, but only 48.2% (n = 53) of the controls reported at least one severe traumatic event. When looking at single events, only few differences were found between patients and controls. Compared to controls, patients described significantly higher rates of psychiatric disorders in their families, in particular depression. Parental rearing styles were rated as more unfavorable in the patient group. In a logistic regression model, of all possible etiological factors examined, only a family history of psychiatric disorders showed a significant influence (OR = 3.6). Melancholic depression seems to be less associated with traumatic events than other psychiatric disorders.

Variation in reproductive life history traits between two populations of Blackbanded Darters (Percina nigrofasciata)

USGS Publications Warehouse

Hughey, Myra C.; Heins, David C.; Jelks, Howard L.; Ory, Bridget A.; Jordan, Frank

2012-01-01

We examined the life history of Blackbanded Darters (Percina nigrofasciata) from two streams in the Choctawhatchee River drainage, Florida, over a three-year study period. Blackbanded Darters from Turkey Creek were longer than fish from Ten Mile Creek; however, size-adjusted clutch and egg sizes were similar between populations. Larger females produced larger clutches, whereas egg size did not vary with female body size. Seasonally, clutch sizes were greater in May than in August. When contrasted with previous studies of Blackbanded Darters in Alabama and Louisiana, the reproductive season of Blackbanded Darters in Florida was unusually long, ceasing for only a few months in late fall. The reproductive season was longer in Turkey Creek than in Ten Mile Creek. Differences in thermal regime among streams may explain differences in life history traits among local and distant populations of Blackbanded Darters. This research, alone and in combination with previous studies of this species, emphasizes two main points. First, it reaffirms that life history studies based on a single locality or conducted at a single point in time may fail to capture the full range of variation in life history traits. Second, it highlights the extensive phenotypic variation found in species with broad geographic ranges. Such species lend themselves to comparative and experimental research on patterns and causes of life history variation.

History in the Early Nineteenth Century.

PubMed

Ratcliff, Jessica

2016-09-01

At the turn of the nineteenth century, at its headquarters in the City of London, the Honourable East India Company established a new museum and library. By midcentury this museum would contain one of Europe’s most extensive collections of the natural history, arts, and sciences of Asia. This essay uses the early history of the company’s museum, focusing in particular on its natural history collections, to explore the material relationship between scientific practice and the imperial political economy. Much of the collections had been gathered in the wake of military campaigns, trade missions, or administrative surveys. Once specimens and reports arrived in Leadenhall Street and passed through the museum storage areas, this plunder would become the stuff of science, going on to feed the growth of disciplines, societies, and projects in Britain and beyond. In this way, the East India Company was integral to the information and communication infrastructures within which many sciences then operated. Collections-based disciplines and societies flourished in this period; their growth, it is argued, was coextensive with administrative and political economic change at institutions like the East India Company. The essay first explores the company’s practices and patterns of collecting and then considers the consequences of this accumulation for aspects of scientific practice—particularly the growth of scientific societies—in both London and Calcutta.

An early history of T cell-mediated cytotoxicity.

PubMed

Golstein, Pierre; Griffiths, Gillian M

2018-04-16

After 60 years of intense fundamental research into T cell-mediated cytotoxicity, we have gained a detailed knowledge of the cells involved, specific recognition mechanisms and post-recognition perforin-granzyme-based and FAS-based molecular mechanisms. What could not be anticipated at the outset was how discovery of the mechanisms regulating the activation and function of cytotoxic T cells would lead to new developments in cancer immunotherapy. Given the profound recent interest in therapeutic manipulation of cytotoxic T cell responses, it is an opportune time to look back on the early history of the field. This Timeline describes how the early findings occurred and eventually led to current therapeutic applications.

Terrestrial Biomarkers for Early Life on Earth as Analogs for Possible Martian Life Forms: Examples of Minerally Replaced Bacteria and Biofilms From the 3.5 - 3.3-Ga Barberton Greenstone Belt, South Africa

NASA Technical Reports Server (NTRS)

Westall, F.; McKay, D. S.; Gibson, E. K.; deWit, M. J.; Dann, J.; Gerneke, D.; deRonde, C. E. J.

1998-01-01

The search for extraterrestrial life and especially martian life hinges on a variety of methods used to identify vestiges of what we could recognize as life, including chemical signatures, morphological fossils, and biogenic precipitates. Although the possibility of extant life on Mars (subsurface) is being considered, most exploration efforts may be directed toward the search for fossil life. Geomorphological evidence points to a warmer and wetter Mars early on in its history, a scenario that encourages comparison with the early Earth. For this reason, study of the early terrestrial life forms and environment in which they lived may provide clues as to how to search for extinct martian life. As a contribution to the early Archean database of terrestrial microfossils, we present new data on morphological fossils from the 3.5-3.3-Ga Barberton greenstone belt (BGB), South Africa. This study underlines the variety of fossil types already present in some of the oldest, best-preserved terrestrial sediments, ranging from minerally replaced bacteria and bacteria molds of vaRious morphologies (coccoid, coccobacillus, bacillus) to minerally replaced biofilm. Biofilm or extracellular polymeric substance (EPS) is produced by bacteria and appears to be more readily fossilisable than bacteria themselves. The BGB fossils occur in shallow water to subaerial sediments interbedded with volcanic lavas, the whole being deposited on oceanic crust. Penecontemporaneous silicification of sediments and volcanics resulted in the chertification of the rocks, which were later subjected to low-grade metamorphism (lower greenschist).

Interpersonal violence, early life adversity, and suicidal behavior in hypersexual men

PubMed Central

Chatzittofis, Andreas; Savard, Josephine; Arver, Stefan; Öberg, Katarina Görts; Hallberg, Jonas; Nordström, Peter; Jokinen, Jussi

2017-01-01

Background and aims There are significant gaps in knowledge regarding the role of childhood adversity, interpersonal violence, and suicidal behavior in hypersexual disorder (HD). The aim of this study was to investigate interpersonal violence in hypersexual men compared with healthy volunteers and the experience of violence in relation to suicidal behavior. Methods This case–control study includes 67 male patients with HD and 40 healthy male volunteers. The Childhood Trauma Questionnaire – Short Form (CTQ-SF) and the Karolinska Interpersonal Violence Scale (KIVS) were used for assessing early life adversity and interpersonal violence in childhood and in adult life. Suicidal behavior (attempts and ideation) was assessed with the Mini-International Neuropsychiatric Interview (version 6.0) and the Montgomery–Åsberg Depression Rating Scale – Self-rating. Results Hypersexual men reported more exposure to violence in childhood and more violent behavior as adults compared with healthy volunteers. Suicide attempters (n = 8, 12%) reported higher KIVS total score, more used violence as a child, more exposure to violence as an adult as well as higher score on CTQ-SF subscale measuring sexual abuse (SA) compared with hypersexual men without suicide attempt. Discussion Hypersexuality was associated with interpersonal violence with higher total scores in patients with a history of suicide attempt. The KIVS subscale exposure to interpersonal violence as a child was validated using the CTQ-SF but can be complemented with questions focusing on SA for full assessment of early life adversity. Conclusion Childhood adversity is an important factor in HD and interpersonal violence might be related to suicidal behavior in hypersexual men. PMID:28467102

Sports, Physical Activity and Recreation in Early American History.

ERIC Educational Resources Information Center

Ballou, Ralph B.

Sports and physical recreation activities have been part of American life since the days of the early settlers. Although the settlers were faced with problems of survival, accounts of life in the colonies in the 1600's carry mention of bowling in the streets, play with bows and arrows, and ice skating. Other activities to gain popularity before…

A qualitative study of early family histories and transitions of homeless youth.

PubMed

Tyler, Kimberly A

2006-10-01

Using intensive qualitative interviews with 40 homeless youth, this study examined their early family histories for abuse, neglect, and other family problems and the number and types of transitions that youth experienced. Multiple forms of child maltreatment, family alcoholism, drug use, and criminal activity characterized early family histories of many youth. Leaving home because of either running away or being removed by child protective services often resulted in multiple transitions, which regularly included moving from foster care homes to a group home, back to their parents, and then again returning to the streets. Although having experienced family disorganization set youth on trajectories for early independence, there were many unique paths that youth traveled prior to ending up on the streets.

Horizontal Gene Transfer and the History of Life

PubMed Central

Daubin, Vincent; Szöllősi, Gergely J.

2016-01-01

Microbes acquire DNA from a variety of sources. The last decades, which have seen the development of genome sequencing, have revealed that horizontal gene transfer has been a major evolutionary force that has constantly reshaped genomes throughout evolution. However, because the history of life must ultimately be deduced from gene phylogenies, the lack of methods to account for horizontal gene transfer has thrown into confusion the very concept of the tree of life. As a result, many questions remain open, but emerging methodological developments promise to use information conveyed by horizontal gene transfer that remains unexploited today. PMID:26801681

Different Levels of Hypoxia Tolerance during Early Life History Stages of Key Fish Species from the Northern Benguela Upwelling Ecosystem Inferred from the Comparison of Eco-Physiological Traits

NASA Astrophysics Data System (ADS)

Geist, S. J.; Imam, R. M.; Kunzmann, A.; Ekau, W.

2016-02-01

Global change factors such as a pronounced Oxygen Minimum Zone and the shoaling of hypoxic waters are assumed to play a major role in controlling the recruitment of fish stocks in Upwelling Systems by affecting the planktonic early life history stages. Ecological and ecophysiological traits in the larval stages of five key fish species in the Northern Benguela Upwelling System (Sardine, Sardinops sagax; Anchovy, Engraulis encrasicolus; Cape horse mackerel, Trachurus capensis; Cape hake, Merluccius sp.; Pelagic goby, Sufflogobobius bibarbatus) were investigated during the GENUS (Geochemistry and Ecology of the Namibian Upwelling Ecosystem) research project . Analysis of vertical larval distributions in relation to the depth of hypoxic water layers showed gradual interspecific differences, suggesting lower hypoxia tolerance levels of the small pelagics Sardine and Anchovy. Cape horse mackerel juveniles and larvae exhibited very high tolerance levels to short-term hypoxia in respirometry stress experiments, close to the levels of the extremely hypoxia-tolerant Pelagic goby. In the latter two species, we also measured the highest activities of anaerobic enzymes (pyruvate kinase and lactate dehydrogenase) in early and late larval stages, compared to very low activities in Sardine larvae. A higher amount of anaerobic enzymatic activity is related to a higher capacity to break down metabolites that build up during phases of oxygen debt and thus help the larvae to quickly recover from hypoxia exposure. In consequence, a high hypoxia tolerance during their early life stages allows Cape horse mackerel and Pelagic goby to successfully reproduce in an environment characterized by frequent hypoxic events. The low hypoxia tolerance of Sardine larvae, eventually resulting in higher mortality rates, is likely to be an important factor to understand the poor reproductive success and continuing recruitment failures of this formerly dominant fish species of the NBUS during the last

Molecular Phylogenetics of the Genus Neoconocephalus (Orthoptera, Tettigoniidae) and the Evolution of Temperate Life Histories

PubMed Central

Snyder, Robert L.; Frederick-Hudson, Katy H.; Schul, Johannes

2009-01-01

Background The katydid genus Neoconocephalus (25+ species) has a prominent acoustic communication system and occurs in large parts of the Neotropics and Nearctic. This group has been subject of numerous behavioral, physiological, and evolutionary studies of its acoustic communication system. Two distinct life histories occur in this group: The tropical life history incorporates multiple generations/year and direct egg development without environmental triggers. Temperate life history is characterized by overwintering in the egg stage, cold trigger of egg development, and one generation/year. This study reconstructs the phylogenetic relationships within the genus to (1) determine the evolutionary history of the temperate life history, and (2) to support comparative studies of evolutionary and physiological problems in this genus. Methodology/Principal Findings We used Amplified Fragment Length Polymorphisms (AFLP), and sequences of two nuclear loci and one mitochondrial locus to reconstruct phylogenetic relationships. The analysis included 17 ingroup and two outgroup species. AFLP and mitochondrial data provided resolution at the species level while the two nuclear loci revealed only deeper nodes. The data sets were combined in a super-matrix to estimate a total evidence tree. Seven of the temperate species form a monophyletic group; however, three more temperate species were placed as siblings of tropical species. Conclusions/Significance Our analyses support the reliability of the current taxonomic treatment of the Neoconocephalus fauna of Caribbean, Central, and North America. Ancestral state reconstruction of life history traits was not conclusive, however at least four transitions between life histories occurred among our sample of species. The proposed phylogeny will strengthen conclusions from comparative work in this group. PMID:19779617

Precedents of perceived social support: personality and early life experiences.

PubMed

Kitamura, T; Kijima, N; Watanabe, K; Takezaki, Y; Tanaka, E