Modelling species interactions in macroevolution and macroecology

One of the most amazing phenomena in the world is the coexistence of an incredible diversity of species. How and why species have evolved so distinct morphological traits from a common ancestor constantly puzzles biologists. Although substantial details in underlying mechanisms of ecology and evolution remain to be revealed, biotic and abiotic interactions are widely accepted as key drivers. I investigate the influence of species interactions on macroecological and macroevolutionary patterns. I confirmed that species interactions can slow down diversity accumulation if the environment has a limited capacity to host species of the same trophic level. However, spatial geographic structure may reduce the power of current methods to detect local limits to diversification. This result indicates that biologists need to be cautious when using diversity-dependent diversification to explain species assembly. Besides species diversity, species interactions can also influence trait diversity. I use a novel model to explain how trait evolution unfolds under environmental stabilizing selection and species interactions together with population dynamics. This model can potentially lead to novel approaches in phylogenetic comparative methods. Furthermore, I use a simulation model to explore how an ecological hypothesis of species interactions - the phylogenetic Janzen-Connell effect - results in a wide range of realistic macroecological and macroevolutionary community patterns. To summarize, species interactions are the fundamental elements beneath any biological mechanism and require further research to better understand the world we are living in