Conférence L Thaler : Rosemary Grant & Peter Grant

In search of the causes of evolution: Darwin's finches on Galapagos

More than 14 species of Darwin’s finches evolved from a common ancestor in the Galápagos archipelago in the last two million years.

Although this iconic adaptive radiation happened in the past, we have sought an understanding of the causes through studies of contemporary populations. A long-term study of four species on the small island of Daphne Major has shown natural selection and introgressive hybridization to be key processes.

Directional selection on ecologically significant morphological traits such as beak size and body size occurs moderately frequently when the environment changes. Species hybridize, rarely, and exchange genes because under favorable conditions the hybrids are as fit as the parental species that gave rise to them. Depending on circumstances, introgression can either cause two species to collapse to one or leads to the formation of a new species. The latest, current, phase of research is designed to investigate the radiation at the molecular level.

INFORMATION

Heure : 11:30-12:30

Lieu : Amphithéatre de la Délégation CNRS - 1919 Route de Mende, Montpellier