Saturday, November 25, 2017
A study published on Thursday in the journal Science reported on formation of a new bird species on the Ecuadorean Galápagos Islands. Researchers from Princeton University in the United States and Uppsala University in Sweden reported the new species evolved in just two generations, though this process had been believed to take much longer, due to breeding between an endemic Darwin finch, Geospiza fortes, and the immigrant cactus finch, Geospiza conirostris.
Princeton University scientists B. Rosemary Grant and Peter Grant, who were conducting their field work on the island of Daphne Major, noticed a non-native male bird — cactus finches — on the island in 1981. The research team said they believe the immigrant bird was native to Española Island, which is located about 100 kilometres (60 miles) southeast of the Galápagos archipelago. Cactus finches have bigger body and beak as compared to other finch species living on the island at the time.
Interbreeding between the two different species of finches produced fertile offspring of a new species. However, these were not able to attract native finches for copulation and thus had to mate within their own new species, making them genetically and reproductively isolated. Currently, there are about 30 birds belonging to the new species. These birds were able to adapt to their environment, and sustain themselves in the food chain. The Grants’ team paired up with Leif Andersson, a professor of Uppsala University, for the genetic analysis of the birds using blood samples.
Researcher B. Rosemary Grant said, “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.” The isolated island helped the biologists to study evolution due to natural selection.
All the eighteen species of finches in the archipelago had a common ancestor, from which they evolved in the course of time due to natural selection. Some of them were discovered by English naturalist Charles Darwin. Also regarded as the father of evolution, Darwin studied these birds to come up with his theory of natural selection. Darwin later wrote On the Origin of Species after his study of the Ecuadorean islands.
