Evolution as the Control of Development by Ecology

Abstract

Chapter 8 concentrated on epigenetic control within organismal ontogeny. In Part Three I discussed how that control builds embryos and their organ systems, while in Part Four we saw how the same processes form the developmental bases for major transitions during evolution. In this chapter, I continue this theme by considering epigenetic interactions between species and between species and their environment. Many such interactions are known as cyclomorphosis or seasonal polymorphism , both of which are examples of phenotypic plasticity.Chapter 19 then moves us to genetic assimilation, the other major mechanism by which environmental signals trigger changes in development. Then, in Chapter 20, I present a quantitative genetics model that integrates epigenetic and environmental factors into analyses of morphological change in development and evolution. The generality of the model is supported by its elaboration for mammalian mandibles and eyespots on butterfly wings.

‘A plausible argument could be made that evolution is the control of development by ecology. Oddly, neither area has figured importantly in evolutionary theory since Darwin, who contributed much to each.’ Van Valen, 1973, p. 488