The structure and import of developmental genetic explanations of evolutionary novelty

Alan Love
History and Philosophy of Science, University of Pittsburgh

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     Last modified: June 15, 2005
     Presentation date: 07/14/2005 4:00 PM in MACK 236
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Abstract
Much of contemporary evolutionary developmental biology (Evo-devo) can be characterized as the use of new molecular tools to answer longstanding morphological questions about evolutionary change, such as the origin of evolutionary novelties. Although developmental genetic tools are widely utilized in Evo-devo, their precise role in explanations of evolutionary novelties remains to be assessed. This is desirable given recent claims by biologists: “The evolution of new morphological features is due predominantly to modifications of spatial patterns of gene expression” (Gompel et al. 2005). In order to comprehend the structure of these explanations and their import, the origin of vertebrate jaws is used as a case study. First, the phylogenetic context from vertebrate history is discussed along with recent results from the use of molecular tools in exploring craniofacial ontogeny. Second, developmental genetic evidence and explanations for the origin of vertebrate jaws are reviewed. The final section evaluates the nature, structure, and import of developmental genetic explanations of evolutionary novelties using results from earlier work on the criteria of explanatory adequacy for the problem of innovation and novelty (ISHPSSB 2003 – Vienna). My analysis connects with existing philosophical discussions concerning explanatory pluralism in biology and generates methodological recommendations for existing Evo-devo research.