lifehistory

Life history refers to the suite of traits that shape an organism's schedule of growth, development, reproduction, and survival. The central aim is to maximize reproductive success within environmental constraints. A life history profile includes age at maturity, lifespan, the number and size of offspring, reproduction frequency, and the level of parental or social investment. Growth rate, developmental timing, and dormancy or migration may also be included.

Life history theory examines trade-offs between traits. Resources are finite, so organisms face choices such as investing in early reproduction at the cost of future survival, or producing many small offspring versus a few large ones. Reproductive strategies are described as semelparity (single reproductive event) versus iteroparity (repeated reproduction). Related concepts include r-selected strategies favoring high fecundity in unstable environments and K-selected strategies favoring offspring quality in stable environments.

Variation arises from genetic differences, environmental conditions, and ecological interactions. Survivorship curves (Type I, II, III) summarize mortality patterns across ages and help compare life histories across taxa. Humans typically show late maturity and substantial parental investment, while many insects and annual plants exhibit rapid growth and high fecundity.

Life history research informs conservation biology, agriculture, and anthropology, helping explain the diversity of life histories. Critics contend that life history is a descriptive framework rather than a universal law, and that plasticity and cultural factors can blur simple classifications.