Tetrapods (four-limbed vertebrates) invaded the land more than 370 million years ago and began to diversify into a spectacular range of morphologies and life modes, rapidly achieving a global distribution. However, due to the inherent temporal and spatial bias of the fossil record, global patterns of tetrapod diversity and biogeography during critical intervals of the group’s evolution remain unresolved. This thesis focuses on examining the patterns and drivers of tetrapod diversity during two of these key intervals. Firstly, advanced statistical, phylogenetic, and modelling approaches were used to examine the impact of major environmental change on the first tetrapods to emerge onto land during the late Palaeozoic (358–272 million years ago). Next, these approaches were combined with palaeoclimatic reconstructions to examine the influence of climate on tetrapod diversity during the early Mesozoic (237–174 million years ago), when modern vertebrate groups, including the dinosaurs, were originating. Together, the results provide a comprehensive assessment of the impact of sampling biases on estimates of past diversity, as well as providing greater insights into the role of environmental and climate change on tetrapod diversity and biogeography
