Life-history strategies

Résumé 0

The biological and demographic profile of a population is defined by a set of biological traits such as age or size at first reproduction, fecundity rate, lifespan, mortality rate of each age group, etc. This demographic profile represents a certain adaptation of a population to its environment. The theory of adaptive strategies is based on the assumption that demographic, ecological, ethological and physiological features of a population are co-adapted and modelled by natural selection.Since environmental changes are continuous, each state of adaptation is only provisional, and the sustainability of a species depends on its aptitude for adapting its demographic strategy to new environmental conditions in order to maintain large populations.Over the last forty years, several studies have tried to explain the origin of variability of characters among organisms. The various methods of reproduction and their degrees of success in various environments thus formed a basis for theoretical and empirical research referred to as “life history”.Life history studies attempt to explain the trade-off between reproductive and demographic parameters (Stearns, 1983a; Reznick, 1985; Pease & Bull, 1988) in relation to various environmental conditions (Whittaker & Goodman, 1979; Winnemiller & Rose, 1992).