Research

A major goal of our research is to understand the processes that generate diversity in the number of lineages. This is a primary challenge in the field of macroevolution; we are only beginning to be able to explain why some branches of the Tree of Life are so much more diverse than others. We have used meta-analyses of molecular phylogenies to uncover some apparent regularities to how patterns of biodiversity arise; for example, the formation of new species often appears fastest where there are fewer other species around. But we have also identified some fundamental limits to how much we can learn about these patterns from molecular data alone. In an article published in Nature, we discovered that there was fundamentally insufficient information in molecular phylogenies (no matter how large) to distinguish between some alternative hypotheses for why some groups are more diverse than others; without additional (non-molecular) data, researchers cannot for example, disentangle changes in historical rates of species formation from that of extinction. We have since demonstrated that this finding likely resolves a 30-year old mystery in evolutionary biology — why extinction estimates from molecular phylogenies are often unrealistically low — and also applies to inferences from molecular epidemiology.