Phylogenetic studies and new fossil evidence have yielded fundamentalinsights into the pattern and timing of dinosaur evolution and the emergence offunctionally modern birds. The dinosaurian radiation began in the MiddleTriassic, significantly predating the global dominance of dinosaurs by the endof the period. The phylogenetic history of ornithischian and saurischiandinosaurs reveals evolutionary trends such as increasing body size. Adaptationsto herbivory in dinosaurs were not tightly correlated with marked floralreplacements. Dinosaurian biogeography during the era of continental breakupprincipally involved dispersal and regional extinction.