- Feb 27, 2016
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Bird seen becoming new species
"In 1981, the researchers noticed the arrival of a male of a non-native species, the large cactus finch.
Professors Rosemary and Peter Grant noticed that this male proceeded to mate with a female of one of the local species, a medium ground finch, producing fertile young.
Almost 40 years later, the progeny of that original mating are still being observed, and number around 30 individuals.
"It's an extreme case of something we're coming to realise more generally over the years. Evolution in general can happen very quickly," said Prof Roger Butlin, a speciation expert who wasn't involved in the study.
...
And in this paper, new genetic evidence shows that after two generations, there was complete reproductive isolation from the native birds. As a result, they are now reproductively - and genetically - isolated. So they have been breeding exclusively with each other over the years.
"What we are saying is that this group of birds behave as a distinct species. If you didn't know anything about [Daphne Major's] history and a taxonomist arrived on this island they would say there are four species on this island," said Prof Andersson.
There is no evidence that they will breed again with the native medium ground finch, but even if they did, they now have a larger size and can exploit new opportunities. Those advantageous traits may be maintained by natural selection.
So hybridisation can lead to speciation, simply through the addition of one individual to a population. It may therefore be a way for new traits to evolve quickly.
"If you just wait for mutations causing one change at a time, then it would make it more difficult to raise a new species that way. But hybridisation may be more effective than mutation," said Prof Butlin."
"In 1981, the researchers noticed the arrival of a male of a non-native species, the large cactus finch.
Professors Rosemary and Peter Grant noticed that this male proceeded to mate with a female of one of the local species, a medium ground finch, producing fertile young.
Almost 40 years later, the progeny of that original mating are still being observed, and number around 30 individuals.
"It's an extreme case of something we're coming to realise more generally over the years. Evolution in general can happen very quickly," said Prof Roger Butlin, a speciation expert who wasn't involved in the study.
...
And in this paper, new genetic evidence shows that after two generations, there was complete reproductive isolation from the native birds. As a result, they are now reproductively - and genetically - isolated. So they have been breeding exclusively with each other over the years.
"What we are saying is that this group of birds behave as a distinct species. If you didn't know anything about [Daphne Major's] history and a taxonomist arrived on this island they would say there are four species on this island," said Prof Andersson.
There is no evidence that they will breed again with the native medium ground finch, but even if they did, they now have a larger size and can exploit new opportunities. Those advantageous traits may be maintained by natural selection.
So hybridisation can lead to speciation, simply through the addition of one individual to a population. It may therefore be a way for new traits to evolve quickly.
"If you just wait for mutations causing one change at a time, then it would make it more difficult to raise a new species that way. But hybridisation may be more effective than mutation," said Prof Butlin."
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