I am interested in understanding patterns of biodiversity at different geographic and temporal scales from the latitudinal diversity gradient to island biogeography, and explaining the tremendous disparity in the number of species among different taxonomic groups. I study the origin and evolution of biodiversity by reconstructing time-calibrated phylogenetic (phylogenomic) trees to estimate evolutionary processes governing biodiversity assemblages over space and time. I apply macroevolutionary approaches to address questions in various topics, including species richness patterns, speciation, niche evolution and conservatism, life-history evolution, adaptive radiation, ecological diversification, rates and patterns of diversification, phylogenomics, and responses of species to past environmental changes.