November 23, 2017
The arrival 36 years ago of a strange bird to a remote island in the Galapagos archipelago has provided direct genetic evidence of a novel way in which new species arise.
In this week's issue of the journal Science, researchers from Princeton University and Uppsala University in Sweden report that the newcomer belonging to one species mated with a member of another species resident on the island, giving rise to a new species that today consists of roughly 30 individuals.
The study comes from work conducted on Darwin's finches, which live on the Galapagos Islands in the Pacific Ocean. The remote location has enabled researchers to study the evolution of biodiversity due to natural selection.
The direct observation of the origin of this new species occurred during field work carried out over the last four decades by B. Rosemary and Peter Grant, two scientists from Princeton, on the small island of Daphne Major.
"The novelty of this study is that we can follow the emergence of new species in the wild," said B. Rosemary Grant, a senior research biologist, emeritus, and a senior biologist in the Department of Ecology and Evolutionary Biology. "Through our work on Daphne Major, we were able to observe the pairing up of two birds from different species and then follow what happened to see how speciation occurred."
In 1981, a graduate student working with the Grants on Daphne Major noticed the newcomer, a male that sang an unusual song and was much larger in body and beak size than the three resident species of birds on the island.