I am an integrative evolutionary biologist broadly interested in patterns and processes of organismal diversification, associated changes in morphological disparity, organism-environment interactions, and how diversity is structured in space and over time. What mechanisms are causing differentiation among populations, and ultimately reproductive isolation? How do speciation processes interact in space and time to give rise to evolutionary radiations? Do speciation mechanisms allow us to predict the susceptibility of the resulting taxa to extinction and thus the macroevolutionary fate of clades? How can we explain the remarkable differences in 'evolutionary success' we often observe in closely related branches of the tree of life? To answer these and related questions, people in my group integrate data on extant and fossil biota and apply microevolutionary and macroevolutionary approaches to contrasting predictions of evolutionary theory with empirical data. These data include genomic, morphological and ecological data and work on natural and experimental populations. Our main model system consists of African freshwater mollusks, notably the evolutionary radiations of these mollusks in the East African Rift System, often integrating extant and fossil mollusks.