Friday seminar: Phylogenetic Analyses of Stasis and Punctuated Equilibria
By Folmer Bokma from Umeå University, Sweden
Biologists studying natural populations often observe rapid evolution on the time scale of a PhD study, but in the fossil record many species show prolonged morphological stasis. This apparent discrepancy between micro- and macroevolution has been debated for over a century, and a repeatedly suggested reconciliation has been that evolution is concentrated in speciation events. This hypothesis, currently best known as "punctuated equilibrium", has resisted testing, largely because fossil "morphospecies" may not represent biological species, and because speciation, however quick on a geological timescale, far exceeds the span of a PhD study. With the increased availability of molecular phylogenies and statistical methods to analyse them, we can now study "tempo and mode in evolution" from present-day, biological species, so that we can complement studies of fossil morphology with analyses of physiological and genomic traits of extant species. I will illustrate how such analyses can improve our understanding of speciation, and help falsify hypothesized explanations of evolutionary stasis.
Folmer Bokma, Umeå University, Sweden