Galapagos finches reveal mechanisms behind rapid evolution

An analysis of Darwin's finches show that a new animal species can be created in as quickly as two generations.
By Joseph Scalise | Nov 27, 2017
In a new look at rapid evolution, researchers from both Princeton and Uppsala University have discovered that Darwin's iconic finches can develop into a new species within two generations, recent research published in journal Sciencereports.

The finches on the Galapagos Islands -- collectively known as "Darwin's finches" -- represent a range of different species. That diversity, coupled with the fact that they are completely cut off from the outside world, makes them a perfect way to study evolution.

The team in the study took advantage of that by analyzing birds on the small Galapagos island of Daphne Major. During the research, scientists noted that a bird from another island came to Daphne Major roughly 36 years ago. Researchers took blood samples from the specimen, which was larger and had a different song than native species, and identified it as a large cactus finch.

Once on the island, the finch mated with native birds and created hybrid fledglings that then mated with each other. Despite the large amounts of inbreeding, the process created a genetically distinct species that was completely different from the medium ground finches that call Daphne Major home, Newsweek reports.

This event is surprising because evolution typically comes from gradual changes that take millennia to form. In this case, the shifts were quick, and came from one foreign bird.

"It's an extreme case of something we're coming to realize more generally over the years. Evolution in general can happen very quickly," said Roger Butlin, a speciation expert who was not involved in the study, according to BBC News.

This is not the first time researchers have noted a species forming from hybridization. In fact, many animals today are the result of genetic hybridizing -- where certain species "borrowed" genes from similar ones to form new populations.

What makes this case special is that the secluded nature of the Galapagos islands made it so the cactus finch could not fly home. That geography also isolated the offspring and, because their songs were different than the native birds, they mated with each other instead of seeking out native sexual partners. Those specific circumstances then created a new finch in a relatively short amount of time.

The research is important because it reveals that evolution can occur quite quickly if the conditions are right. It also gives new insight into changes in isolated populations and could one day shed light on the differences between fast evolving and slow evolving populations.

"The novelty of this study is that we can follow the emergence of new species in the wild," said study co-author B. Rosemary Grant, a senior research biologist, emeritus, and a senior biologist in the Department of Ecology and Evolutionary Biology at Princeton University, according to Phys.org. "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."

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