jälkeläismäärät

Jälkeläismäärät is a general term for the number of offspring produced by an individual, a breeding cohort, or a population within a defined period or over a lifetime. The concept is used across disciplines such as human demography, zoology, botany, and ecology, and its exact meaning depends on the species and study design. In human populations, jälkeläismäärät is commonly discussed as fertility or the number of children.

Common metrics include completed fertility (the total number of children a person has by the end of their reproductive years); total fertility rate (the average number of children a woman would have over her lifetime given current age-specific fertility rates); age-specific fertility rates; and, in broader studies, net reproductive rate (R0) or per-capita fecundity. In non-human studies, researchers refer to fecundity (potential reproductive output) or lifetime reproductive success (the number of offspring that survive to reproductive age).

Data sources and challenges include surveys, censuses, birth registries, field observations, and experimental studies. Limitations arise from reporting bias, variation by age, health, socioeconomic factors, environmental conditions, and differences among species. Comparisons across populations or species require careful standardization and context.

Applications of jälkeläismäärät span population projections, demographic forecasting, and conservation planning, as well as evolutionary and ecological research. Ethical considerations involve privacy in human data and the effects of environmental changes on reproductive patterns, which can alter the interpretation and use of the figures.