Optimal allocation of resources to growth and reproduction: Implications for age and size at maturity.

The schedule of growth and reproduction is crucial to maximization of fitness. Models of optimal allocation of limiting resources are useful tools for predicting age and size at maturity - key components of fitness - for all lifestyles. Early models considered annual plants. Recently, they have been generalized to other short-lived organisms and also to perennials in which growth and reproduction schedules following maturation can be predicted. A review of existing models shows that differences in trophic conditions and mortality are the main sources of inter- and intraspecific variation in size.