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Hélène Morlon

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.

Clavel, J., Morlon, H. (2017) Accelerated body-size evolution during cold climatic periods in the Cenozoic Proceedings of the National Academy of Sciences 114: 4183-4188

Manceau, M., Lambert, A., Morlon, H. (2017) A unifying comparative phylogenetic framework including traits coevolving across interacting lineages Systematic Biology 66: 551-568

Lewitus, E., Morlon, H. (2016) Natural constraints to species diversification PloS Biology 14(8): e1002532

Moen, D.S., Morlon, H. Why does diversification slow down? Trends in Ecology and Evolution . (2014)

Morlon, H. Phylogenetic approaches for studying diversification Ecology Letters (2014)

Rolland, J., Condamine, F.L., Jiguet, F., Morlon, H. Faster speciation and reduced extinction in the tropics contribute to the mammalian latitudinal diversity gradient PloS Biology (2014) 12(1): e1001775

Morlon, H., Parsons, T.L., Plotkin, J. Reconciling molecular phylogenies with the fossil record Proceedings of the National Academy of Sciences (2011) 108: 16327-16332




We study long term biodiversity dynamics using phylogenetic (...)
We study long term biodiversity dynamics using phylogenetic trees