The Evolution of Sexual Dimorphism in Recently Established Populations: An Ontogenetic Perspective

Auburn University, Auburn AL

Investigators

Abstract

One hundred and forty years ago Charles Darwin proposed the theory of evolution by natural selection. This theory has been remarkably successful in explaining both the diversity of species of plants and animals and the intricate fit between organisms and their environment. One of the great puzzles remaining for evolutionary biologists is the evolution of sexual dimorphism - differences between males and females of the same species in size, shape, and coloration. Divergence of populations in sexual dimorphism cannot be explained by standard evolutionary theory. The research proposed will test the hypothesis that change in dimorphism of adults is the result of changes in the growth and development (ontogeny) of males and females. To test this idea the investigators will study sex-specific growth patterns of recently established populations of the house finch (Carpodacus mexicanus), a small songbird. This will be the first study of the role of growth and development in evolution of sexual dimorphism in natural populations of vertebrates. Ultimately, this work will provide significant new data and insight into our understanding of how the morphologies of males and female evolve. More generally, these data will increase our understanding of the processes that enable rapid colonization by invasive species and, thereby, aid conservation efforts.