9615383 Grant The goal of the proposed research is to understand the processes involved in speciation and adaptive radiation. It will be carried out on the small island of Daphne Major in the Galapagos archipelago. Previous research has shown that the three species of Darwin's Finches on the island occasionally hybridize. Over the past 20 years almost all individuals on the island have been uniquely banded, and pedigree analysis has shown that hybrids may survive and breed as well as or better than the parental species at certain times. The proposed research will build on the long-term data set to complete a demographic study of the three cohorts of all species and hybrids produced in 1983, 1984 and 1987. These will be the first complete analyses of a cohort of hybrids, possibly for any organism in nature. The study will involve using molecular methods to make unambiguous assignments of parentage, and ecological methods for determining the causes of variation in the fates of individuals. The complete data will allow a measurement of the long-term genetic fitness consequences of hybridization, and will allow modeling of the long-term dynamics of these interacting species. This research is important for understanding the origin and maintenance of biodiversity. Speciation is a key process for generating biological diversity, yet little is known about the ecological and microevolutionary forces responsible for speciation. The proposed research takes advantage of an exceptionally favorable situation for directly investigating some of the forces at work in the final stages of speciation when hybridization is still possible. For conservation biology, the research will help to illuminate the ecological factors that influence genetic variation in small and potentially endangered populations.
