Innovation in Development and Evolution

M�LLER, G.B.; University of Vienna: Innovation in Development and Evolution

Organismal evolution proceeds by a two-stage process: the initial generation of heritable phenotypic differences and the adaptive variation and fixation of these differences in a population. Over many decades evolutionary theory has almost exclusively focused on the latter, variation of characters that already exist, blackboxing the mechanisms that led to their primary generation. The major tenet of the neo-Darwinian synthesis holds that the continued modification and inheritance of a basic genetic toolkit for the regulation of developmental processes, directed by mechanisms acting at the population level, has generated the panoply of organismal forms. As a consequence, much of present day evolutionary theory is concerned with formal accounts of processes at the genetic level, whereas questions of the higher level origination and organization of morphological structure have largely been set aside. Recent appreciation of striking discordances between genetic and morphological evolution and new insights into self-organizing processes that pertain to living tissues have focused new interest on the generative mechanisms of biological form and suggest that morphological innovation should be treated as a distinct problem of evolution. This introductory lecture to the symposium on morphological innovation will summarize the “problem agenda” of innovation in evolutionary biology. It will be argued that innovation can only be successfully approached within a combined evolutionary and developmental framework and that innovation therefore represents one of those biological phenomena in which EvoDevo goes beyond the explanatory reach of neo-Darwinism.

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