Miscellaneous content from the original enlightened caveman. Some serious, some not. Take your chances.

Monday, January 17, 2005

Evolution Versus Creationism - Part 2 - Ring Species

It appears, from my inbox, that I've started something here. (He says as he feigns surprise.) All objections point to "intelligent design" as the achilles heel of Darwin's elegant theory. It appears that this is the real anchor for creationists. They envision it as the AHA! moment in the debate, when deity denying evolutionists will scamper for the corners. Ahem. Not this one. But before I demolish this red herring of an argument, let me just put another nail in the coffin of one other creationist argument - the notion that the fossil record does not back up the assertions of evolution's apologists. Let's talk about ring species.

Ring species provide a unique glimpse into how some species came to be. Here's the dull version: A ring of populations encircles an area of unsuitable habitat. At one location in the ring, two distinct forms coexist without interbreeding. Around the rest of the ring, the traits of one species change gradually through intermediate populations into the second species' traits. Yawn.

Now let me just quote the master himself, Richard Dawkins:

The best known case is the Herring Gull/Lesser Black-backed Gull ring. In Britain these are clearly distinct species, quite different in color. Anybody can tell them apart. But if you follow the population of Herring Gulls westward round the North Pole to North America, then via Alaska across Siberia and back to Europe again, you notice a curious fact. The 'Herring Gulls' become less and less like Herring Gulls and more and more like Lesser Black-backed Gulls until it turns out that our European Lesser Black-backed Gulls actually are the other end of a ring that started out as Herring Gulls. At every stage around the ring, the birds are sufficiently similar to their neighbors to interbreed with them. Until, that is, the ends of the continuum are reached, in Europe. At this point, the Herring Gull and the Lesser Black-backed Gull never interbreed, although they are linked by a continuous series of interbreeding colleagues all the way round the world. The only thing that is special about ring species like these gulls is that the intermediates are still alive. All pairs of related species are potentially ring species. The intermediates must have lived once. It is just that in most cases they are now dead.

"Gaps In The Mind" from A Devil's Chaplain (2003)

As has previously been stated, the fossil record is indeed discontinuous, but the preferred explanation is not that the life forms required by evolutionary theory did not exist. With ring species, evolving viruses and bacteria, the maturation of the human immune response, and many other examples, it's obvious that evolution happened and is still happening in lots of circumstances. Nevertheless, it's truly amazing how easy it is to disbelieve the obvious when you desperately want to. A good friend, a creationist no less, when commenting on women who know their men are cheating but stay anyway, is fond of saying, "They want to believe." That always strikes me as funny. (You know I love ya, buddy.)

1 Comments:

Blogger Chris Wilson said...

I feel I should prempt this inevitable statement.

"Above 0.5, you quickly have a makeshift fishing net! Think about that. If you found this button and thread net hanging in your garage, would you think of it as a net or as a collection of buttons and threads?"

Uh, ok, maybe it wouldn't seem a fishing net. I was overzealous with that metaphor. Shall we say, no harm, no foul?

1/18/2005 01:04:00 AM

 

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