Developmental Constraints in Evolutionary Processes

Abstract

Epigenetic interactions during development drastically constrain processes of morphological change during evolution. Development does not only define the apportionment of phenotypic variation upon which selection operates, but it can result in discontinuities and directionality in morphological transformations. It is argued that these properties of development in evolution are simply the result of the dynamic nature of developmental programs. Considerations of developmental mechanisms in evolution are essential to understand phyletic trends since developmental interactions basically define the universe of possible morphologies and impose limits on the directional action of natural selection.