My central research questions concern rates of evolution and major features of the diversification of life: How are diversity and evolutionary rates best measured, especially in light of the incompleteness of the fossil record? Are changes in the rate of taxonomic diversification more strongly driven by changes in origination rate or by changes in extinction rate? How and why have the relative contributions of origination and extinction to diversity change varied during the Phanerozoic? How continuous or discontinuous are the true patterns of origination and extinction that underlie the observed record of taxonomic first and last appearances? To address these questions, I use mathematical modeling of evolution and preservation as well as analysis of taxonomic and stratigraphic data.

I regularly teach a general course in principles of paleontology and two graduate courses, one in mathematical modeling of paleobiological problems and one in multivariate data analysis. My students have worked on a wide variety of problems, including morphogenesis, determinants of evolutionary rates within single lineages, patterns of community change in the recent past, the evolution of complexity, and the evolution of community structure.