Adaptation and Development: On the Lack of Common Ground

Abstract

Science magazine recently asked more than 100 developmental biologists two questions. The first asked for opinions on the greatest unanswered questions in developmental biology. The second asked which areas would see the most progress in the next five years. Among the unanswered questions, “What is the relation between development and evolution?” scored second, just behind “What are the molecular mechanisms of morphogenesis?” But when the respondents were asked to name the areas in which progress was expected, the role of development in evolution fell to 11th out of 12. No other question showed so much disparity between importance and expectation of progress (Barinaga 1994). The study of adaptation is at the core of modern evolutionary biology. Natural selection, the explanation of adaptation, is also the primary force for evolutionary change. Developmental biology is only at the periphery of this study, even with the recent explosion of knowledge in molecular and developmental genetics. The Science questionnaire showed that developmental biologists are very interested in the relevance of development to evolution but are pessimistic about discovering its nature. Developmental biology is not integrated into mainstream evolutionary biology. In this chapter I argue that this situation has resulted from clashes in methodology between the primarily adaptationist practices, methodologies, and theories of mainstream evolution theory and the contrasting practices, methodologies, and theories of developmental biology. Contemporary evolution theory has its origins in the Modern Synthesis of the 1930s and 1940s (Mayr and Provine 1980). The Synthesis was centered on population genetics.