Adaptation: A Life History Perspective

Abstract

The use of optimization models to study adaptations is discussed. The optimal value of a trait must maximize fitness, that is, lifetime reproductive success. This means that every trait under optimization must be translated into demographic parameters Although there is no universal measure of fitness, some general rules are given about whether net reproductive rate R or intrinsic population growth rate r should be maximized in given conditions, Models maximizing R are usually simple, and they produce easy-to-interpret predictions. The scope of applicability of models assuming maximization of R broadens if we are satisfied with post hoc explanations of natural patterns (predictions in a weak sense). Optimization models should be verified using comparative methods. With a comparative method, however, optimization models become tools for approaching general questions about selective forces and the resulting patterns, not for studying local adaptations, Hypotheses about local adaptations are always difficult to test, and optimization models seem of little help here.