Why development matters

Günter Wagner's Homology, Genes, and Evolutionary Innovation is a compelling, and empirically well-supported account of the evolution of character identity and character origination which emphasizes the importance of homology and novelty as central explananda for 21st century evolutionary biology (and developmental bias as a key explanans). In this essay review, I focus on the similarities and differences between the structuralist picture of evolutionary biology advocated by Wagner, and that presented by standard evolutionary theory. First, I outline the ways in which Wagner's genetic theory of homology diverges from the account of homology offered by standard evolutionary theory. Then, I consider the motivations for these divergences. Lastly, I discuss a number of concerns with Wagner's view, and offer some concluding thoughts on the relationship between structuralism and adaptationism.