Adaptive Aspects of Development: A 30-Year Perspective on the Relevance of Biomechanical and Allometric Analyses

Abstract

The participants of the 1981 Dahlem conference questioned whether evolutionary history largely reflects the operation of natural selection, physical forces, historical accidents, or some combination of all three operating on developmental phenomena. They asserted that answering this question requires the help of biophysical (biomechanical) and allometric analyses. However, the participants also recognized that this kind of approach was insufficient at the time to answer this question. I review what was then known about these kinds of analyses, and I discuss how they have matured since 1981. I also illustrate how allometric analyses can be applied usefully to understand the role of natural selection and physical forces during the evolution of plants. I argue that neither biomechanics nor allometry is sufficient to provide a mechanistic explanation for the phenomena discussed during the 1981 Dahlem conference and that neither will mature sufficiently to do so since each lacks a mechanistic, theoretical foundation in the context of evolutionary and developmental biology.