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Evolution at last! In an English country garden

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great tits/fotoparus, fotolia

From ScienceDaily:

A British enthusiasm for feeding birds may have caused UK great tits to have evolved longer beaks than their European counterparts, according to new research.

The specific gene sequences which had evolved in the British birds were found to closely match human genes known to determine face shape. There were also strong similarities with genes identified with beak shape in Darwin’s study of finches — one of the best-known examples of how physical traits have adapted to different environments in the wild. This led the researchers to think that great tit beaks were evolving by natural selection in British great tits, perhaps in response to the widespread use of bird feeders.Paper. (paywall) – Mirte Bosse, Lewis G. Spurgin, Veronika N. Laine1, Ella F. Cole, Josh A. Firth, Phillip Gienapp1, Andrew G. Gosler, Keith McMahon, Jocelyn Poissant, Irene Verhagen, Martien A. M. Groenen, Kees van Oers, Ben C. Sheldon, Marcel E. Visser, Jon Slate, Recent natural selection causes adaptive evolution of an avian polygenic trait, Science 20 Oct 2017: Vol. 358, Issue 6361, pp. 365-368, DOI: 10.1126/science.aal3298 More.

The widespread use of bird feeders isn’t, strictly speaking, natural selection, but we will let that pass. Darwin’s finches appear to have morphed back and forth with respect to beak shape and if this is the best we can come up with for natural selection, things are worse than we thought.

Alternatively, maybe some people are just too quick to write media releases.

But something about this story sounded familiar and lo, lost in the mists of early internet time, what did I find but, back in 2005, the Washington Post thought it had found squirrel evolution:

Apparently, 18 black Canadian squirrels were released at the Smithsonian in Washington D.C. in the early 1900s. As anyone who has lived in Toronto would predict, they soon began to jostle the local gray squirrels at area bird feeders.

The Post writer announces,

That’s because those 18 squirrels — whose coats of lustrous black set them apart from the native animals — were the beginning of a shift that has changed the complexion of Washington’s backyard critters. Now, probably because of a slight evolutionary advantage conveyed with a black coat, the descendants of these squirrels have spread all the way into Rockville and Prince William County.

Seriously: Scientists say it’s a real-life example of natural selection at work, which has rolled on for a century here without much public notice.

“It shows the spread of a gene within a population,” said Richard W. Thorington Jr., a Smithsonian Institution researcher working on a book that includes a history of the District’s black squirrels. “That is evolutionary change before your eyes.”

Wow. Seriously? Evolutionary change before my eyes? But wait a minute … The Post writer then goes on to say,

The story of Washington’s black squirrels — which scientists say are just a color variation within the common gray squirrel species — still has its shades of mystery.

Yes, that’s right, folks. The grey and the black squirrels are actually two coat-type varieties of the same species. They are about as different genetically as black and white alley cats are from orange and white alley cats.

Here in Toronto, the two coat types have persisted together for many decades, doing a proportionate amount of damage to spring flower gardens and native bird feeders. But apparently in the Washington area a century ago, for some reason, only the greys were found, until a zookeeper acquired some of the black variety from Canada and let them go.

In a classic example of Darwinian just-so storytelling, we are informed, “Here’s why some scientists believe the black squirrels were multiplying: In winter, their dark coats allowed them to retain heat from sunlight, leaving them less desperate for warmth than their lighter-colored cousins.”

Well, if that is the case, why do the supposedly disadvantaged grey-coat type squirrels survive at all in cities like Toronto that can become much colder than Washington? Yet their relative proportion of the squirrel population here does not seem to have changed much over the decades.

In reality, the black squirrels are multiplying in Washington because that’s what squirrels do, given a chance. In Toronto, the black squirrels tend to be somewhat more numerous than the grey, but unlike the Darwinists, I am not going to offer a just-so story as to why that is so. A genome map might possibly demonstrate that black is the dominant colour, but I don’t know of any such map in existence now. [2005]

Oh, by the way, do the squirrels even care which coat type they are? One scientist explains,

“… the squirrels don’t appear to treat each other differently because they are black or gray.” “They don’t seem to care,” he said.

Personally, I can’t imagine why the squirrels would even know, let alone care.

The key thing to see here is that the Darwinist wants us to understand that the process that (he hopes) can explain why pesky black-coat-type squirrels can get established in the Washington area alongside grey members of the same species can also explain the entire history of life. But he never demonstrates that point, he merely assumes it as an article of faith. And he then expects the rest of us to take these utterly trivial instances of animals adapting to an environment as evidence for his thesis. No wonder they are restless over there in Kansas. ( Post-Darwinist, May 20, 2005)

See also: Darwin’s finches not a good example of Darwinian evolution

This vid attempts to straighten out squirrel relationships:

I for one am glad that they finally found something. willspeaks

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