Institut de Biologie de l'École Normale Supérieure ENS . CNRS UMR8197 . Inserm U1024 Directeur : Pierre Paoletti

Modeling Biodiversity

This team is part of the Computional Biology Center.

Goal

Understanding the ecological and evolutionary processes underlying current biodiversity patterns

Background

What are the ecological and evolutionary processes underlying current biodiversity patterns ? What is the evolutionary history of species diversity on this planet, and where is it headed, in particular in the context of global change ? These are the big overarching questions motivating our research. We combine mathematics, bioinformatics and global scale data to study questions ranging from macroevolution and macroecology to community assembly, biogeography, and conservation. We particularly enjoy working with molecular phylogenies ; we use them to study speciation, extinction, dispersal, phenotypic evolution and community assembly. We work closely with mathematicians, phylogeneticists, and field ecologists.

Research highlights

We develop stochastic models that allow us to estimate speciation and extinction rates from molecular phylogenies, and to understand how and why these rates vary in time and space. We apply these models to large datasets of amphibians, mammals, bird, plants, and even microorganisms, in order to study long tem diversity dynamics. Despite a long tradition in ecology of using equilibrium biodiversity theories, we found that only few species groups have reached (or even will reach) such dynamic equilibriums. Nevertheless, speciation rates do tend to decrease as evolution proceeds. We proposed explications to this diversification slowdown that differ from ‘classical’ explanations based on equilibrium theories. We also used phylogenetic approaches to study the latitudinal biodiversity gradient and found, in mammals, that the tropics are altogether a cradle, a museum and a biodiversity ‘pump’. More recently, the team developed models that allow studying the long term evolution of phenotypes. In particular it developed models better accounting for the effect of interspecific interactions (such as competition) and past environmental changes (such as climatic change) on phenotypic evolution. Using these models, the team was able to show that body-size evolved faster during cold than during warm geological periods in birds and mammals. We currently pursue our modeling efforts and applications to diverse questions and taxonomic groups.