The role of extinction and speciation rates, and the effect of different levels of biological organization on the origin and maintenance of biodiversity

Abstract

Despite the great interest in biodiversity, there are many unanswered questions regarding the patterns and processes that affect the diversity of a given clade or geographical region. This is to some extent due to the lack of understanding of diversification dynamics, which in the end will determine the number of species. Diversity dynamics studies have been traditionally done by paleontologists, but molecular phylogenies also carry historical information and therefore can be also used to study the diversification of different taxonomic groups. The main goal of this project is to study the origination and maintenance of biodiversity. To achieve those goals I will: 1- investigate the role of speciation and extinction rates on the diversification dynamics; 2- characterize the spacial and temporal patterns of diversity dynamics for different taxonomic groups; 3- investigate which potential factors might affect the speciation and extinction rates, and ultimately the diversity trajectory. Special attention will be given to groups showing declining diversity, given that: (a) we still do not know the role of speciation and extinction in this evolutionary scenario; (b) except for conservation biologists this scenario is ignored by most biologists; and (c) the phylogenetic signal of groups in decline has not been properly characterized yet. The effect of different levels of biological organization on the speciation and extinction rates will also be investigated. Those include for example the rates of morphological evolution and the spacial distribution of species. Additionally, the project will evaluate the limitations of current analytical tools used to study the diversity dynamics and will, if possible, develop new tools that integrate different approaches. The fossil record, molecular phylogenies, numerical simulations and ecological data will be used to achieve those goals. I expect that the integration of those four different approaches will result in a better understanding of different aspects related to diversification dynamics, and that the results from this project help on the development of a theory that explains the origin and maintenance of biodiversity. (AU)