THE RELATIONSHIP BETWEEN EVOLUTIONARY-THEORY AND PHYLOGENETIC ANALYSIS

The relationship between phylogenetic reconstruction and evolutionary theory is reassessed. It is argued here that phylogenies, and evolutio nary principles, should be analysed initially as independently from ea ch other as possible. Only then can they be used to test one another. If the phylogenies and evolutionary principles are totally consistent with one another, this consilience of independent lines of evidence in creases confidence in both. If, however, there is a conflict, then one should assess the relative support for each hypothesis, and tentative ly accept the more strongly supported one. We review examples where th e phylogenetic hypothesis is preferred over the evolutionary principle , and vice versa, and instances where the conflict cannot be readily r esolved. Because the analyses of pattern and process must initially be kept separate, the temporal order in which they are performed is unim portant. Therefore, the widespread methodology of always proceeding fr om cladogram to evolutionary 'scenario' cannot be justified philosophi cally. Such an approach means that cladograms cannot be properly teste d against evolutionary principles, and that evolutionary 'scenarios' h ave no independent standing. Instead, we propose the 'consilience' app roach where phylogenetic and evolutionary hypotheses are formulated in dependently from each other and then examined for agreement.