scholarly journals Divergent selection on, but no genetic conflict over, female and male timing and rate of reproduction in a human population

2013 ◽  
Vol 280 (1772) ◽  
pp. 20132002 ◽  
Author(s):  
Elisabeth Bolund ◽  
Sandra Bouwhuis ◽  
Jenni E. Pettay ◽  
Virpi Lummaa
Keyword(s):  
Life History ◽  
Sexual Conflict ◽  
Human Population ◽  
Human Life ◽  
Genetic Correlations ◽  
Life History Evolution ◽  
Reproductive Traits ◽  
Phenotypic Selection ◽  
Reproductive Rate ◽  
Genetic Conflict

The sexes often have different phenotypic optima for important life-history traits, and because of a largely shared genome this can lead to a conflict over trait expression. In mammals, the obligate costs of reproduction are higher for females, making reproductive timing and rate especially liable to conflict between the sexes. While studies from wild vertebrates support such sexual conflict, it remains unexplored in humans. We used a pedigreed human population from preindustrial Finland to estimate sexual conflict over age at first and last reproduction, reproductive lifespan and reproductive rate. We found that the phenotypic selection gradients differed between the sexes. We next established significant heritabilities in both sexes for all traits. All traits, except reproductive rate, showed strongly positive intersexual genetic correlations and were strongly genetically correlated with fitness in both sexes. Moreover, the genetic correlations with fitness were almost identical in men and women. For reproductive rate, the intersexual correlation and the correlation with fitness were weaker but again similar between the sexes. Thus, in this population, an apparent sexual conflict at the phenotypic level did not reflect an underlying genetic conflict over the studied reproductive traits. These findings emphasize the need for incorporating genetic perspectives into studies of human life-history evolution.

The evolution of childhood as a by-product?

2006 ◽  
Vol 29 (3) ◽  
pp. 288-289
Author(s):  
Peter Kappeler
Keyword(s):  
Life History ◽  
Life Histories ◽  
Nonhuman Primates ◽  
Homo Sapiens ◽  
Human Life ◽  
Life History Evolution ◽  
History Evolution ◽  
Linguistic Skills

The proposition that selective advantages of linguistic skills have contributed to shifts in ontogenetic landmarks of human life histories in early Homo sapiens is weakened by neglecting alternative mechanisms of life history evolution. Moreover, arguments about biological continuity through sweeping comparisons with nonhuman primates do not support various assumptions of this scenario.

Endocrinology

2019 ◽  
pp. 612-672
Author(s):  
Richard G. Bribiescas
Keyword(s):  
Life History ◽  
Social Dynamics ◽  
Human Life ◽  
Life History Evolution ◽  
Sexually Dimorphic ◽  
Human Variation ◽  
Men And Women ◽  
Metabolic Hormones ◽  
Gene Environment ◽  
Key Aspects

This chapter on endocrinology aims to shed light on the biology of hormones within the context of human life history evolution. An evolutionary perspective contributes to not only our understanding of human evolution, but also to the contemporary and emerging health challenges across the spectrum of ecologies and environments. Evolutionary endocrinology extends our understanding of human biology and health through the engagement of gene–environment interactions, social dynamics, human variation, and how hormones regulate life history traits such as growth, immune function, metabolism, and ageing. This chapter describes key aspects of endocrinology that are specific to men and women, while also being mindful of the importance of human variation. For example, men and women exhibit reproductive states that deploy specific functions. In women, these are menstruation, gestation, and lactation. These processes are governed largely by the hypothalamic–pituitary–ovarian axis and how it responds to environmental challenges such as nutritional demands, activity, and social stresses. Men also exhibit reproductive states, although they are mostly in the form of investment in sexually dimorphic tissue and behavioural variation. These states are governed by hormones which allocate resources between tissues that are indicative of different forms of reproductive effort. These include sexually dimorphic muscle tissue and adiposity. Spermatogenesis is obviously key but has differential effects on fertility compared to gametogenesis in women. Additional aspects of human evolutionary endocrinology include stress homoeostasis and metabolism, which involve the hypothalamic–pituitary–adrenal axis as well as the thyroid and other metabolic hormones.

scholarly journals Inclusive fitness and differential productivity across the life course determine intergenerational transfers in a small-scale human society

2015 ◽  
Vol 282 (1803) ◽  
pp. 20142808 ◽  
Author(s):  
Paul L. Hooper ◽  
Michael Gurven ◽  
Jeffrey Winking ◽  
Hillard S. Kaplan
Keyword(s):  
Life History ◽  
Inclusive Fitness ◽  
Human Life ◽  
Intergenerational Transfers ◽  
Essential Element ◽  
Life History Evolution ◽  
Small Scale ◽  
Human Society ◽  
Extended Lifespan ◽  
The Life Course

Transfers of resources between generations are an essential element in current models of human life-history evolution accounting for prolonged development, extended lifespan and menopause. Integrating these models with Hamilton's theory of inclusive fitness, we predict that the interaction of biological kinship with the age-schedule of resource production should be a key driver of intergenerational transfers. In the empirical case of Tsimane’ forager–horticulturalists in Bolivian Amazonia, we provide a detailed characterization of net transfers of food according to age, sex, kinship and the net need of donors and recipients. We show that parents, grandparents and siblings provide significant net downward transfers of food across generations. We demonstrate that the extent of provisioning responds facultatively to variation in the productivity and demographic composition of families, as predicted by the theory. We hypothesize that the motivation to provide these critical transfers is a fundamental force that binds together human nuclear and extended families. The ubiquity of three-generational families in human societies may thus be a direct reflection of fundamental evolutionary constraints on an organism's life-history and social organization.

scholarly journals Isolation and predation drive gecko life-history evolution on islands

2020 ◽  
Vol 129 (3) ◽  
pp. 618-629
Author(s):  
Rachel Schwarz ◽  
Yuval Itescu ◽  
Antonis Antonopoulos ◽  
Ioanna-Aikaterini Gavriilidi ◽  
Karin Tamar ◽  
...  
Keyword(s):  
Life History ◽  
Life Histories ◽  
Life History Traits ◽  
Life History Evolution ◽  
Reproductive Traits ◽  
Predation Pressure ◽  
Ecological Studies ◽  
Island Populations ◽  
Island Syndrome ◽  
Insular Populations

Abstract Insular animals are thought to be under weak predation pressure and increased intraspecific competition compared with those on the mainland. Thus, insular populations are predicted to evolve ‘slow’ life histories characterized by fewer and smaller clutches of larger eggs, a pattern called the ‘island syndrome’. To test this pattern, we collected data on egg volume, clutch size and laying frequency of 31 Aegean Island populations of the closely related geckos of the Mediodactylus kotschyi species complex. We tested how predation pressure, resource abundance, island area and isolation influenced reproductive traits. Isolation and predation were the main drivers of variation in life-history traits. Higher predator richness seemed to promote faster life histories, perhaps owing to predation on adults, whereas the presence of boas promoted slower life histories, perhaps owing to release from predation by rats on the eggs of geckos. Insular geckos followed only some of the predictions of the ‘island syndrome’. Predation pressure seemed to be more complex than expected and drove life histories of species in two opposing directions. Our results highlight the importance of considering the identity of specific predators in ecological studies.

scholarly journals Introduction to special issue: ‘Life history and learning: how childhood, caregiving and old age shape cognition and culture in humans and other animals’

2020 ◽  
Vol 375 (1803) ◽  
pp. 20190489
Author(s):  
Alison Gopnik ◽  
Willem E. Frankenhuis ◽  
Michael Tomasello
Keyword(s):  
Life History ◽  
Old Age ◽  
Developmental Psychology ◽  
Human Life ◽  
Empirical Work ◽  
Reproductive Rate ◽  
Special Issue ◽  
Wide Range ◽  
Cognition And Culture ◽  
High Level

This special issue focuses on the relationship between life history and learning, especially during human evolution. ‘Life history’ refers to the developmental programme of an organism, including its period of immaturity, reproductive rate and timing, caregiving investment and longevity. Across many species an extended childhood and high caregiving investment appear to be correlated with particular kinds of plasticity and learning. Human life history is particularly distinctive; humans evolved an exceptionally long childhood and old age, and an unusually high level of caregiving investment, at the same time that they evolved distinctive capacities for cognition and culture. The contributors explore the relations between life history, plasticity and learning across a wide range of methods and populations, including theoretical and empirical work in biology, anthropology and developmental psychology. This article is part of the theme issue ‘Life history and learning: how childhood, caregiving and old age shape cognition and culture in humans and other animals’.

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