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Life history theory is a method of analysis in animal and human biology, psychology, and especially evolutionary sociobiology which postulates that many of the physiological traits and behaviors of individuals may be best understood in relation to the key maturational and reproductive characteristics that define the life course. Biology is a branch of science, dealing with the study of life. ...
Psychology (ancient Greek: psyche = soul or mind, logos/-ology = study of) is an academic and applied field involving the study of the mind, brain, and behavior, both human and nonhuman. ...
A speculative phylogenetic tree of all living things, based on rRNA gene data, showing the separation of the three domains, bacteria, archaea, and eukaryotes. ...
Sociobiology is a synthesis of scientific disciplines that attempts to explain behaviour in all species by considering the evolutionary advantages of social behaviours. ...
Physiology (in Greek physis = nature and logos = word) is the study of the mechanical, physical, and biochemical functions of living organisms. ...
Behavior (or behaviour in Commonwealth English) refers to the actions or reactions of an object or organism, usually in relation to the environment. ...
Examples of these characteristics include:
- Age at weaning
- Age of sexual maturity or puberty
- Adult body size
- Time to first sexual activity or mating
- Time to first reproduction
- Duration of gestation
- Litter size
- Interbirth interval
Variations of these characteristics reflect differing allocations of an individual's resources (i.e., time, effort, and energy expenditure) to competing life functions, especially growth, body maintenance, and reproduction. For an individual, the resources in a particular environment are finite. Time, effort, and energy used for one purpose diminishes the time effort, and energy available for another. For example, resources spent growing to a larger body size cannot be spent increasing the number of offspring. A breastfeeding infant Breastfeeding is the practice of a woman feeding an infant (or sometimes a toddler or a young child) with milk produced from her mammary glands, usually directly from the nipples. ...
Puberty refers to the process of physical changes by which a childs body becomes an adult body capable of reproduction. ...
For other uses, see Reproduction (disambiguation) Reproduction is the biological process by which new individual organisms are produced. ...
Gestation is the carrying of an embryo or fetus inside a female viviparous animal. ...
Growth can refer to: Auxology Bacterial growth Cell growth Economic growth For financial growth due to simple interest or compound interest see Interest Exponential growth Fungal growth Logistic growth Growth hormone Personal growth Population growth Tumours can sometimes be referred to as a growth This is a disambiguation page: a...
Thus allocation of resources involves trade-offs. These trade-offs and strategies can be compared between species. Two of the most well-known trade-offs involve number of offspring (few or many) and timing of reproduction (accelerated maturation and reproduction versus delayed, allowing for larger size and more complex social supports). The extremes at the species level of these fundamental dimensions of reproduction were recognized long before life history theory, and are traditionally termed r/K selection theory. An r-selection strategy is the production of a large number of offspring (of whom only a minority may survive) as early in life as possible. The K-selection strategy is to produce a smaller number of "fitter" offspring with higher survival chances. r/K selection theory is a set of descriptions of species reproductive behaviors, concerned with modeling the amount of offspring as well as the nurturing aspect of the species to those offspring. ...
In ecology, r-selection (note: lower case r) relates to the selection of traits (in organisms) that allow success in unstable or unpredictable environments. ...
In ecology, K-selection (note : upper case K) relates to the selection of traits (in organisms) that allow success in stable or predictable environments. ...
According to life history theory the individuals of a species are able to make limited shifts in reproductive strategies in response to the prevailing environments. Depending on abundance of resources and probable individual longevity, individuals consciously or unconsciously shift their reproductive strategy in one direction or the other to take advantage of available resources or to compensate for resource shortage or uncertainty.
Life histories of individual human beings may be analyzed from the same perspectives, and the theory provides some explanatory and predictive power when applied to groups of people in different life situations. For example, it predicts that in a stressful environment, or one with uncertain resources, sexual development, mating, and pregnancy may be accelerated, with acceptance of higher risks and production of more children, while security and high resource availability tend to favor slower maturation, later mating, and fewer offspring.
Life history theory has provided new perspectives in understanding many aspects of human reproductive behavior, such as the relationship between poverty and fertility. A number of statistical predictions have been confirmed by social data, though not always reproducibly. The implications for social policy have been hotly debated because statistical associations are not always causal, and a preferred interpretation may be a more minor factor than another unpalatable relationship.
See also Behavioral ecology is the study of the ecological and evolutionary basis for animal behavior, and the roles of behavior in enabling an animal to adapt to its environment (both intrinsic and extrinsic). ...
Evolutionary developmental psychology, (or EDP), is the application of the basic principles of Darwinian evolution, particularly natural selection, to explain contemporary human development. ...
Human behavioral ecology (HBE) or human evolutionary ecology applies the principles of evolutionary theory and optimization to the study of human behavioral and cultural diversity. ...
Somatic effort refers to the total investments of an organism in its own development, differentiation, and maintenance and thus consequently increasing its reproductive potential. ...
References - Charnov, E. L. (1993). Life history invariants. Oxford, England: Oxford University Press.
- Ellis, B.J. (2004). Timing of pubertal maturation in girls: an integrated life history approach. Psychological Bulletin. 130:920-58.
- Roff, D. (1992). The evolution of life histories: Theory and analysis. New York:Chapman & Hall.
- Stearns, S. (1992). The evolution of life histories. Oxford, England: Oxford University Press.
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