A Developmental-Physiological Perspective on the Development and Evolution of Phenotypic Plasticity

Abstract

Our understanding of the development and evolution of phenotypic plasticity has evolved in the 30 years since the first Dahlem conference on development and evolution. The focus of this review is on the developmental mechanisms that produce alternative and conditional phenotypes in response to environmental signals. The role of environment is a critical factor in evolution, yet environment is almost universally ignored in developmental biology. The effects of environment are most clearly seen in postembryonic development, where the mechanisms by which environmental signals alter developmental trajectories are increasingly well understood. The outcome of altered developmental pathways is what we recognize as phenotypic plasticity. This chapter shows that the developmental mechanisms that produce phenotypic plasticity are diverse and that control resides largely at the physiological level, often via developmental hormones that switch between alternative developmental fates in response to environmental signals. In conclusion this chapters shows how robustness and homeostatic mechanisms are they key to understanding the evolution of conditional traits.