Friday, October 28, 2022
12:00 p.m. - 1:00 p.m.
Title: Insights into the Processes Behind the Origin and Maintenance of Biodiversity
One of the foundational goals of evolutionary biology is to understand why biodiversity varies so dramatically across taxa, space and time. Ultimately, heterogeneity in the number of species can only result from different number of speciation, extinction and dispersal events. Through development and use of new process-generating probabilistic models, we characterise the mode and tempo of diversification dynamics. We develop explicit spatio-temporal models of diversification that highlight the roles of differential extinction and asymmetrical dispersal in building the present-day latitudinal gradient in tetrapods and dispute differences in speciation rates, which undergo clade-specific responses to environmental variations. By enabling inference on a flexible diversification model where speciation and extinction rates diffuse through time, we question the long-standing view that periods of fast diversification are sustained by clade-wide trends and find an imbalanced diversification process wherein lineages sporadically give rise to many, less speciation-prone descendants. While our findings show general deterministic environmental effects, particularly on species persistence, they uncover a more nuanced, dynamic and unpredictable diversification process.