Anyone remember Darwin’s finches? The clinch bird for Darwinian evolution?
“It’s been observed that the species of Darwin’s finches sometimes hybridise – Peter and Rosemary Grant have seen that during their fieldwork,” Prof Andersson told the BBC.
“But it’s difficult to say what the long-term evolutionary significance of that is. What does it contribute?”
What it contributes is that one would be hard pressed to show that there is any evolution going on, in the face of this much hybridization.
Birds on the Galápagos Islands have developed new eating habits
“We met some scepticism when we submitted the manuscript for our article. People simply didn’t believe it was possible. But it is — the birds really do drink nectar,” says Olesen.
“The biology on these islands is completely different for instance to South America. We found flycatchers, among others, and they normally live off the insects they catch. There simply aren’t that many insects here on the islands, which means that many of them have been forced to find other sources of food,” he says.
“These birds are highly opportunistic and they change their behaviour as they go. They eat more or less anything they can get at. It was once believed that they were very vulnerable to disruption — but that no longer holds true. If there’s a shortage of insects they simply eat something else,” says Olesen.
Mikkel Willemoes, a post-doc at the Natural History Museum of Denmark, agrees with him.
“It’s odd that there are so many introduced species of plants in the Galápagos Islands. There has been no long-term specialised evolution. These birds are highly opportunistic and quick to adapt. They have to be on these islands. The species that survive are the ones that adapt to new conditions,” says Willemoes.
The need to see Darwin in all things causes researchers to miss the obvious: The finches hybridize a lot and the birds generally eat whatever they can find.
That makes it difficult to identify Darwinian evolution at work anywhere except in the textbooks. Doubtless, they’ll go back to catching flies when they find some.
Moral: Never trust your grand theory to a flock of hungry air mice.
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