Adaptive speciation: the role of natural selection in mechanisms of geographic and non-geographic speciation.
Recent discussion of mechanism has suggested new approaches to several issues in the philosophy of science, including theory structure, causal explanation, and reductionism. Here, I apply what I take to be the fruits of the 'new mechanical philosophy' to an analysis of a contemporary debate in evolutionary biology about the role of natural selection in speciation. Traditional accounts of that debate focus on the geographic context of genetic divergence--namely, whether divergence in the absence of geographic isolation is possible (or significant). Those accounts are at best incomplete, I argue, because they ignore the mechanisms producing divergence and miss what is at stake in the biological debate. I argue that the biological debate instead concerns the scope of particular speciation mechanisms which assign different roles to natural selection at various stages of divergence. The upshot is a new interpretation of the crux of that debate-namely, whether divergence with gene flow is possible (or significant) and whether the isolating mechanisms producing it are adaptive.
Baker
Jason M
JM
Department of History and Philosophy of Science, Indiana University, Goodbody Hall 130, 1011 East Third Street, Bloomington, IN 47405, USA. bakerjm@indiana.edu
D000220:Adaptation, Biological; D051456:Gene Flow; D040961:Genetic Drift; D049810:Genetic Speciation; D049672:History, 19th Century; D049673:History, 20th Century; D049674:History, 21st Century; D006801:Humans; D012586:Science / Q000266:history*; D012641:Selection, Genetic