We propose a simple model for genetic adaptation to a changing environment, describing a fitness landscape characterized by two maxima. One is associated with "specialist" individuals that are adapted to the environment; this maximum moves over time as the environment changes. The other maximum is static, and represents "generalist" individuals not affected by environmental changes. The rest of the landscape is occupied by "maladapted" individuals. Our analysis considers the evolution of these three subpopulations. Our main result is that, in presence of a sufficiently stable environmental feature, as in the case of an unchanging aspect of a physical habitat, specialists can dominate the population. By contrast, rapidly changing environmental features, such as language or cultural habits, are a moving target for the genes; here, generalists dominate, because the best evolutionary strategy is to adopt neutral alleles not specialized for any specific environment. The model we propose is based on simple assumptions about evolutionary dynamics and describes all possible scenarios in a non-trivial phase diagram. The approach provides a general framework to address such fundamental issues as the Baldwin effect, the biological basis for language, or the ecological consequences of a rapid climate change.
Failure of the fittest: limits on asexual adaptation to changing environments
Univ. Brest, CNRS UMR 6205, Laboratoire de Mathematiques de Bretagne Atlantique（布雷斯特大学）；BioSP, INRAE（法国国家农业食品与环境研究院）；Department of Ecology & Evolutionary Biology, University of Toronto（多伦多大学）
Two waves of adaptation: speciation induced by dormancy in a model with changing environment
Institute of Mathematics, BOKU University（博库大学数学研究所）；School of Mathematical and Statistical Sciences, Arizona State University（亚利桑那州立大学数学与统计科学学院）；Department of Mathematics, University of California San Diego（加州大学圣地亚哥分校数学系）
