Published: Mon, November 27, 2017
Health Care | By Alberto Manning

Scientists Spot New Species of Galapagos Finches which Evolved in Few Generations

Scientists Spot New Species of Galapagos Finches which Evolved in Few Generations

The Big Birds became reproductively isolated from the native birds on Daphne Major, a tiny Galapagos island, in just two generations.

Two Princeton scientists, B. Rosemary Grant and Peter Grant, conducted field work on the archipelago over the last four decades.

Rosemary Grant, senior biologist at Princeton in the USA, 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 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 in the Department of Ecology and Evolutionary Biology at Princeton.

The new species of Darwins finch was observed during field work carried out over the last four decades by B Rosemary and Peter Grant, two scientists from the Princeton University in the United States, on the small island of Daphne Major.

Ironically, the case study that led to this startling conclusion - detailed in a paper in the journal Science - concerns the finches of the Galapagos islands, the very collection of birds that helped Charles Darwin formulate his theory regarding the role of natural selection in evolution. This happened because the cactus finch couldn't fly the long distance back home, so was forced to pick a mate from one of the Daphne Major bird species instead of his own.

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Until now it had been thought Big Bird derived from a localised hybrid pairing but genetic analysis now reveals that the original male arrived on Daphne Major in 1981 from Espanola, an island 100 miles away and was a large cactus finch, Geospiza conirostris. It was clear that the bird wasn't from Daphne Major, but its origins were unknown, so the scientists caught and tested the bird's blood before releasing him.

Scientists from Uppsala University analysed DNA collected from the parent birds and their offspring over the years. His species was from Española island.

After reaching maturity, the new Big Birds attempted to find mates of their own only to be met with a big problem. And after two generations, the Big Birds ceased mating with the natives - only among themselves.

The researchers say a striking aspect is that after just two generations, the new lineage behaved as any other species of Darwin's finches would. This shows how important geographical isolation is when it comes to creating new species. "Thus, the combination of gene variants contributed from the two interbreeding species in combination with natural selection led to the evolution of a beak morphology that was competitive and unique". These newly evolved specimens might soon start breeding with other of the three species, which might give rise to a new speciation process.

He adds that a naturalist visiting Great Daphne today and unaware of the Big Birds' history would have no reason to think the species was anything but ancient and firmly rooted on the island.

"We have no indication about the long-term survival of the Big Bird lineage, but it has the potential to become a success, and it provides a lovely example of one way in which speciation occurs", he says.

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