Ancient Bodies, Ancient Lives
Debra L. Martin, Anna J. Osterholtz in Bodies and Lives in Ancient America, 2015
A life-history approach is utilized to examine more closely the important stages within a human lifetime including birth, infancy, childhood, adolescence, adulthood, and the elderly years. This approach aided in organizing the information about important biocultural factors that come into play for different groups during these stages, such as diet, nutrition, living conditions, and things that could harm people at different stages of life. Life-history theory is used to help explain the traits for each group that govern these life events and highlights various adaptations that are made with each stage. Providing only information on disease is not as useful as providing information on the rich context within which disease is buffered or experienced due to various behaviors. Hill summarizes this well when she states that “[i]dentifying health hazards alone, without studying the priorities that govern human decisions, will not affect the mortality rate of individuals who willingly and knowingly incur such risks” (1993: 78).
Evolutionary Theories of Aging: A Systemic and Mechanistic Perspective
Shamim I. Ahmad in Aging: Exploring a Complex Phenomenon, 2017
Independently of the equilibrium between the various known or still unknown processes contributing to the forces of evolution, the purpose of the evolutionary mechanism is to ensure that, on a more or less long-term basis, a species is able to adapt to changes occurring in its environment, a necessary condition to guarantee the perpetuation of the species. Thus, a successful adaptation will result in an improved equilibrium between mortality and reproduction rates in order to allow each generation to produce a larger progeny. Indeed, more descendants imply that the beneficial traits are more easily carried on into future generations and can contribute to strengthening the species. The number of descendants of a species is associated with its fitness function. By modifying the mortality and reproduction rates, evolution works toward increasing the fitness and the fitness function is usually expressed in terms of reproductive and mortality rates. Thus, from an evolutionary perspective, the changing life history traits of a species are the ones whose adaptation induces the most significant difference in the level of fitness.
The ecological context
Loretta A. Cormier, Pauline E. Jolly in The Primate Zoonoses, 2017
Among bats, some evidence exists to support the life history hypothesis. In a study of 15 species of bats in central and western Africa, viral richness was higher in bats that lived in more fragmented forest, but the study also found increased viral richness in larger-bodied bats (Maganga et al. 2014). Thus, life history traits may not simply be a matter of r versus K selection. Bats are believed to be the reservoir host for both Ebola and Marburg viruses (see Chapter 2), with wild primates serving as an intermediate amplifying host whereby the virus can be transmitted to humans through contact with blood, body fluids, and/or tissues. Thus, in the fragmented forest, changes in the host-parasite relationship among viruses and bats likely influence the probability that wild primates are also affected in the fragmented forest, and ultimately, change the risk for human infection
Evolutionary life history theory as an organising framework for cohort studies: insights from the Cebu Longitudinal Health and Nutrition Survey
Published in Annals of Human Biology, 2020
Christopher W. Kuzawa, Linda Adair, Sonny A. Bechayda, Judith Rafaelita B. Borja, Delia B. Carba, Paulita L. Duazo, Dan T. A. Eisenberg, Alexander V. Georgiev, Lee T. Gettler, Nanette R. Lee, Elizabeth A. Quinn, Stacy Rosenbaum, Julienne N. Rutherford, Calen P. Ryan, Thomas W. McDade
Life history theory (LHT) is the branch of evolutionary theory that seeks to understand the evolution of species variation in life cycles, and also how and why they vary across individuals of the same species (Charnov 1991; Hill and Kaplan 1999; Kuzawa and Bragg 2012). For the purpose of human biological investigations using cohorts, LHT provides a framework for formulating a priori, testable hypotheses regarding an organism’s metabolism and pattern of energy allocation to the body’s various functions, and focuses attention on the finite nature of resources and the resultant trade-offs that bind traits into patterns of co-variation. It also inspires hypotheses for how behaviours or experiences early in life might impact various outcomes measured in adulthood, including such traits as reproductive biology, behaviour, immunity and the pace of senescence and functional decline. Life history theory thus provides a useful scaffold for our investigations of human biology and its unfolding across the lifecourse and even across generations.
Effects of the Sex Ratio and Socioeconomic Deprivation on Male Mortality
Published in Archives of Suicide Research, 2020
F. R. Moore, M. Macleod, C. Starkey, I. Krams, T. Roy
Women live longer than men worldwide (Austad, 2006). Proximate-level explanations include endocrinological and behavioral sex differences, such as testosterone-linked risk taking in men (Maklakov & Lummaa, 2013) and a stronger tendency for women to seek help and support (Tamres, Janicki, & Helgeson, 2002). At an ultimate level, life-history theory (e.g., Stearns, 1992) can be used as a theoretical framework for understanding variation in lifespan. Here, both the sex difference in mortality and its proximate underpinnings may stem from sex-specific solutions to the problem of investment of finite somatic resources in the competing demands of reproduction, growth, and survival (Archer, Zajitschek, Sakaluk, Royle, & Hunt, 2012; Clutton-Brock & Isvaran, 2007; Daly & Wilson 1988; Liker, Freckleton, & Székely, 2013).
In Pursuit of Pleasure: A Biopsychosocial Perspective on Sexual Pleasure and Gender
Published in International Journal of Sexual Health, 2021
Ellen T. M. Laan, Verena Klein, Marlene A. Werner, Rik H. W. van Lunsen, Erick Janssen
Even though humans, like other animals, will have acquired general behavioral tendencies aimed at survival and reproduction, they are clearly capable of adapting to life circumstances. Life history theory proposes that adaptive sexual strategies develop during an individual’s life span, rendering the need for the assumption of evolved, innate, deterministic, gendered (cognitive) adaptations obsolete (Del Guidice et al., 2015). Life history theory assumes that global ecological changes, such as climate change, have a larger influence on human mating strategies than evolved adaptations. For instance, stable environments in which adequate resources for survival are available are usually characterized by reproductive strategies aimed at investment in a limited number of children, whereas unstable environments with scarce resources usually lead to more quantitative reproductive strategies with a greater number of offspring (Eshuis, 2020).
Related Knowledge Centers
- Evolution
- Parental Investment
- Senescence
- Natural Selection
- Weaning
- Juvenile
- Sexual Maturity
- Fitness
- Evolutionary Biology
- Evolutionary Ecology