Aging, Life History, and Human Evolution

2020 ◽  
Vol 49 (1) ◽  
pp. 101-121 ◽  
Author(s):  
Richard G. Bribiescas
Keyword(s):  
Life History ◽  
Comparative Research ◽  
Reproductive Effort ◽  
Great Apes ◽  
Population Variation ◽  
Trade Offs ◽  
Evolution Of Aging ◽  
Physical Degradation ◽  
Shed Light ◽  
Over Time

Aging occurs in all sexually reproducing organisms. That is, physical degradation over time occurs from conception until death. While the life span of a species is often viewed as a benchmark of aging, the pace and intensity of physical degradation over time varies owing to environmental influences, genetics, allocation of energetic investment, and phylogenetic history. Significant variation in aging within mammals, primates, and great apes, including humans, is therefore common across species. The evolution of aging in the hominin lineage is poorly known; however, clues can be derived from the fossil record. Ongoing advances continue to shed light on the interactions between life-history variables such as reproductive effort and aging. This review presents our current understanding of the evolution of aging in humans, drawing on population variation, comparative research, trade-offs, and sex differences, as well as tissue-specific patterns of physical degradation. Implications for contemporary health challenges and the future of human evolutionary anthropology research are also discussed.

Life histories of North American game birds: a reanalysis

1988 ◽  
Vol 66 (8) ◽  
pp. 1906-1912 ◽  
Author(s):  
Todd W. Arnold
Keyword(s):  
Life History ◽  
North American ◽  
Life Histories ◽  
Life History Traits ◽  
Reproductive Effort ◽  
Cost Of Reproduction ◽  
Reproductive Value ◽  
Trade Offs ◽  
Game Birds ◽  
The Cost

Recently, Zammuto (R. M. Zammuto. 1986. Can. J. Zool. 64: 2739–2749) suggested that North American game birds exhibited survival–fecundity trade-offs consistent with the "cost of reproduction" hypothesis. However, there were four serious problems with the data and the analyses that Zammuto used: (i) the species chosen for analysis ("game birds") showed little taxonomic or ecological uniformity, (ii) the measures of future reproductive value (maximum longevity) were severely biased by unequal sample sizes of band recoveries, (iii) the measures of current reproductive effort (clutch sizes) were inappropriate given that most of the birds analyzed produce self-feeding precocial offspring, and (iv) the statistical units used in the majority of analyses (species) were not statistically independent with respect to higher level taxonomy. After correcting these problems, I found little evidence of survival–fecundity trade-offs among precocial game birds, and I attribute most of the explainable variation in life-history traits of these birds to allometry, phylogeny, and geography.

Intraspecific variation in reproductive effort by female Parapediasia teterrella (Lepidoptera: Pyralidae) and its relation to body size

1990 ◽  
Vol 68 (1) ◽  
pp. 44-48 ◽  
Author(s):  
Larry D. Marshall
Keyword(s):  
Life History ◽  
Body Size ◽  
Egg Production ◽  
Egg Size ◽  
Reproductive Effort ◽  
Life History Evolution ◽  
Reproductive Parameters ◽  
Trade Offs ◽  
Egg Number ◽  
Lepidoptera Pyralidae

Daily egg production of the moth Parapediasia teterrella declined over the life-span of the female but egg size remained constant. The absence of water resulted in lower fecundity and early mortality. Egg size and lifetime fecundity showed considerable inter-individual variation and large females produced more and larger eggs than their smaller counterparts. Large females expended greater reproductive effort than small females. Hatching success was negatively related to egg size. In spite of this, large females laying large eggs had higher fitness than small females. I postulate that multiple reproductive strategies within a species, resulting from differences in reproductive effort expended, may explain why expected trade-offs in reproductive parameters (e.g., egg size versus egg number) were not found in this species. Furthermore, I argue that the prevalent interpretation of life-history evolution (that body size is the important determining parameter of life-history parameters) may reflect correlation of body size with reproductive effort, and reproductive effort may be more important in determining the nature of trade-offs between reproductive parameters.

scholarly journals Using life history trade-offs to understand core-transient structuring of a small mammal community

2014 ◽  
Author(s):  
Sarah R Supp ◽  
David N. Koons ◽  
S. K. Morgan Ernest
Keyword(s):  
Life History ◽  
Reproductive Effort ◽  
Survival Strategies ◽  
Life History Strategies ◽  
High Survival ◽  
Transient Species ◽  
Ecological Specialization ◽  
Core Species ◽  
Trade Offs ◽  
Source Sink

An emerging conceptual framework suggests that communities are comprised of two main groups of species: core species that are temporally persistent, and transient species that are temporally intermittent. Core and transient species have been shown to differ in spatiotemporal turnover, diversity patterns, and importantly, survival strategies targeted at local vs. regional habitat use. While the core-transient framework has typically been a site-specific designation for species, we suggest that if core and transient species have local vs. regional survival strategies across sites, and consistently differ in population-level spatial structure and gene flow, they may also exhibit different life-history strategies. Specifically, core species should display relatively low dispersal rates, low reproductive effort, high ecological specialization and high survival rates compared to transient species, which may display a wider range of traits given that transience may result from source-sink dynamics or from the ability to emigrate readily. We present results from 21 years of capture-mark-recapture data in a diverse rodent community, evaluating the linkages between temporal persistence, local abundance, and trade-offs among life-history traits. Core species at our site conservatively supported our hypotheses, differing in ecological specialization, survival and dispersal probabilities, and reproductive effort from transient species. Transient species exhibited a wider range of characteristics, which likely stems from the multiple processes generating source-sink dynamics and nomadic transience in local communities. We suggest that trait associations among core-transient species may be similar in other systems and warrants further study.

Reproductive Effort and Costs

2021 ◽  
pp. 59-74
Author(s):  
Jeffrey A. Hutchings
Keyword(s):  
Life History ◽  
Reproductive Success ◽  
Total Energy ◽  
Reproductive Effort ◽  
Life History Evolution ◽  
Reproductive Costs ◽  
Positive Outcomes ◽  
Differential Allocation ◽  
Trade Offs ◽  
Potential Benefits

Predictions about life-history evolution are intellectually bereft without a consideration of trade-offs. Benefits derived from making one life-history ‘decision’ are made at a cost of not realizing potential benefits associated with alternative decisions. These trade-offs are the inevitable product of constraints, often driven by an individual’s differential allocation of fixed resources to reproduction versus survival or growth. These allocations prevent multiple positive outcomes from being simultaneously realized. Reproductive effort is the proportion of total energy or resources allocated to all elements of reproduction. Reproductive effort generates reproductive costs. Increases in current reproductive effort reduce future reproductive success by affecting survival, growth, and/or fecundity. The causal mechanisms of these costs can be energetic, ecological, behavioural, or genetic. Evidence for reproductive costs is widespread. Instances where the evidence of costs is equivocal are usually caused by using among-individual correlations to study what is a within-individual phenomenon.

scholarly journals Techniques for Regulating Military Force

2019 ◽  
pp. 734-752
Author(s):  
Monica Hakimi
Keyword(s):  
Comparative Research ◽  
Use Of Force ◽  
Armed Forces ◽  
Foreign Affairs ◽  
Military Force ◽  
War Powers ◽  
The World ◽  
The Government ◽  
Shed Light ◽  
Over Time

This chapter draws on the five chapters that follow—each of which describes the war powers in a single country—to identify and analyze some of the techniques for regulating this area of foreign affairs and then to reflect on the value of comparative research on it. Three basic techniques are: (1) to establish substantive standards on when the government may or may not use force, (2) to divide among different branches of government the authority to deploy the country’s armed forces, and (3) to subject such decisions to oversight or review. There is considerable variation, both across countries and over time within particular countries, in how and with what effect each technique is used. Given that variation, comparative war powers research might be of limited relevance to national officials who make use of force decisions or to analysts who seek to explain them. Rather, the principal benefit of such research might be to bring into stark relief each country’s own national ethos—to shed light on how it defines itself and conceives of its relationship with the rest of the world

Life History Adaptation in Prey

2018 ◽  
pp. 323-346
Author(s):  
Gary A. Wellborn
Keyword(s):  
Life History ◽  
Life History Theory ◽  
Reproductive Effort ◽  
Life History Evolution ◽  
Reproductive Value ◽  
Offspring Size ◽  
Selective Predation ◽  
Antipredator Defense ◽  
Trade Offs ◽  
History Evolution

Predation is a powerful agent of life history evolution in prey species, as demonstrated in diverse examples in crustaceans. Ubiquitous size- and age-selective predation mediates trade-offs among reproductive effort, survival, and growth, which cause evolution of constitutive and phenotypically plastic shifts in age and size at maturity. In accord with predictions of life history theory, comparative studies demonstrate that contrasting forms of selective predation generate divergent evolutionary changes in age- and size-specific allocation of reproductive effort within populations and species. Predation risk also influences egg and offspring size, and some crustaceans exhibit phenotypic plasticity in offspring size in response to chemical cues of predators. Because age-selective predation impacts the relative benefits of earlier versus later reproductive investment, predation may also shape senescence and life span of crustaceans. Additionally, individual differences in risk-taking behavior, sometimes termed “personalities,” have been examined in several crustaceans, and these may arise through among-individual variation in reproductive value. Finally, in some crustacean groups limb autotomy is a common, but costly, antipredator defense, and life history perspectives on autotomy suggest individuals may balance costs and benefits during predator encounters. Much of our understanding of predation’s role in life history evolution of prey derives from studies of crustaceans, and these organisms continue to be promising avenues to elucidate mechanisms of life history evolution.

scholarly journals Developmental plasticity of the stress response in female but not in male guppies

2018 ◽  
Vol 5 (3) ◽  
pp. 172268 ◽  
Author(s):  
L. Chouinard-Thuly ◽  
A. R. Reddon ◽  
I. Leris ◽  
R. L. Earley ◽  
S. M. Reader
Keyword(s):  
Life History ◽  
Stress Response ◽  
Stress Responses ◽  
Early Life ◽  
Developmental Plasticity ◽  
Life Experiences ◽  
Population Variation ◽  
Small Fish ◽  
Cortisol Release ◽  
Over Time

To survive, animals must respond appropriately to stress. Stress responses are costly, so early-life experiences with potential stressors could adaptively tailor adult stress responses to local conditions. However, how multiple stressors influence the development of the stress response remains unclear, as is the role of sex. Trinidadian guppies ( Poecilia reticulata ) are small fish with extensive life-history differences between the sexes and population variation in predation pressure and social density. We investigated how sex and early-life experience influence hormonal stress responses by manipulating conspecific density and perceived predation risk during development. In adults, we sampled cortisol twice to measure initial release and change over time in response to a recurring stressor. The sexes differed considerably in their physiological stress response. Males released more cortisol for their body mass than females and did not reduce cortisol release over time. By contrast, all females, except those reared at high density together with predation cues, reduced cortisol release over time. Cortisol responses of males were thus less dynamic in response to current circumstances and early-life experiences than females, consistent with life-history differences between the sexes. Our study underscores the importance of early-life experiences, interacting ecological factors and sex differences in the organization of the stress response.

scholarly journals Using life history trade-offs to understand core-transient structuring of a small mammal community

2015 ◽  
Author(s):  
Sarah R Supp ◽  
David N. Koons ◽  
S. K. Morgan Ernest
Keyword(s):  
Life History ◽  
Reproductive Effort ◽  
Survival Strategies ◽  
Life History Strategies ◽  
High Survival ◽  
Transient Species ◽  
Ecological Specialization ◽  
Core Species ◽  
Trade Offs ◽  
Source Sink

An emerging conceptual framework suggests that communities are composed of two main groups of species through time: core species that are temporally persistent, and transient species that are temporally intermittent. Core and transient species have been shown to differ in spatiotemporal turnover, diversity patterns, and importantly, survival strategies targeted at local vs. regional habitat use. While the core-transient framework has typically been a site-specific designation for species, we suggest that if core and transient species have local vs. regional survival strategies across sites, and consistently differ in population-level spatial structure and gene flow, they may also exhibit different life-history strategies. Specifically, core species should display relatively low movement rates, low reproductive effort, high ecological specialization and high survival rates compared to transient species, which may display a wider range of traits given that transience may result from source-sink dynamics or from the ability to emigrate readily in a nomadic fashion. We present results from 21 years of capture-mark-recapture data in a diverse rodent community, evaluating the linkages between temporal persistence, local abundance, and trade-offs among life-history traits. Core species at our site conservatively supported our hypotheses, differing in ecological specialization, survival and movement probabilities, and reproductive effort relative to transient species. Transient species exhibited a wider range of characteristics, which likely stems from the multiple processes generating transience in local communities, such as source-sink dynamics at larger regional scales or nomadic life history strategies. We suggest that trait associations among core-transient species may be similar in other systems and warrants further study.

scholarly journals Macroevolution of dimensionless life history metrics in tetrapods

2019 ◽  
Author(s):  
Cecina Babich Morrow ◽  
S. K. Morgan Ernest ◽  
Andrew J. Kerkhoff
Keyword(s):  
Life History ◽  
Body Mass ◽  
Life History Traits ◽  
Reproductive Effort ◽  
Life History Strategies ◽  
Offspring Size ◽  
Evolutionary Transitions ◽  
Trade Offs ◽  
Survival And Reproduction ◽  
The Impact

AbstractLife history traits represent organism’s strategies to navigate the fitness trade-offs between survival and reproduction. Eric Charnov developed three dimensionless metrics to quantify fundamental life history trade-offs. Lifetime reproductive effort (LRE), relative reproductive lifespan (RRL), and relative offspring size (ROS), together with body mass, can be used classify life history strategies across the four major classes of tetrapods: amphibians, reptiles, mammals, and birds. First, we investigate how the metrics have evolved in concert with body mass. In most cases, we find evidence for correlated evolution between body mass and the three metrics. Finally, we compare life history strategies across the four classes of tetrapods and find that LRE, RRL, and ROS delineate a space in which the major tetrapod clades occupy mostly unique subspaces. These distinct combinations of life history strategies provide us with a framework to understand the impact of major evolutionary transitions in energetics, physiology, and ecology.

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