Investigating the historical dynamics of diversification using molecular phylogenies
A central challenge in evolutionary biology is to explain why some taxonomic groups and some time periods have so many species while others have so few; ultimately this means estimating and explaining variation in rates of diversification (speciation and extinction). Unfortunately, for many groups the fossil record is so sparse that the only information we have on past dynamics of diversity comes from time-calibrated molecular phylogenies of extant lineages. There is now an abundance of increasingly sophisticated methods for extracting this information and these have, collectively, been used in thousands of studies and have substantially contributed to our understanding of the drivers of diversity through time. However, there has been persistent controversy about the reliability of inferences made from phylogenies including only extant species. In this talk, I will address this issue and try and clarify what precisely we can learn about diversification from molecular phylogenies. I will then use this framework to assess what (if any) generalities emerge about the process of diversification from many different phylogenetic studies.