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Posted January 13, 2002

Hello, you're listening to Mostly Mozart on CJLY 93.5fm Nelson, Kootenay Coop Radio. My name is Tom Clegg. Mostly Mozart is sponsored by Tom Clegg.


Some prankster gave me a copy of the Skeptical Inquirer recently, and it's got an interesting piece about evolution in schools. Apparently one of the reasons why most North Americans don't learn much about evolution in school, is that a lot of our biology teachers don't really know much about it themselves. Apparently, a lot of people still want to ban the teaching of evolution. Maybe I can relate to this: I wouldn't want gunfighting to be taught in schools, because I don't want the kids to grow up to be gunfighters. Perhaps I wouldn't want evolution to be taught in schools, if I didn't want the kids to evolve. Obviously, evolution doesn't work that way -- you don't have to believe it in order to participate in it. And individuals don't evolve anyway; populations do. But then, maybe these are the things that many biology teachers don't know.

I thought about this poor-education theory, and it agrees pretty well with my experience in public school in Ontario. I don't remember exactly when, but I know I did get some exposure to evolution in elementary school. Or, to be precise, I was exposed to some ideas that are related to the concept of evolution in general.

I knew Charles Darwin's name, although I'm not sure whether I picked it up from school, parents, or books. I saw a tree-like chart of animals, which pointed out a lot of similarities between different species that have existed at various times. The most revolutionary part of this was that you could follow everything back to a single common starting point. Evidently, the animals are related to each other in some way, and humans are related to the animals in some way.

Nobody ever told me what the theory of natural selection was. I didn't know that the idea of evolution was well established by the time Charles Darwin arrived on the scene, and that all of the typical anti-evolution arguments date back to the first half of the 19th century, before Darwin.

In fact, the thing that keeps surprising me the most about popular conceptions of evolution is that none of the critics of evolution seem to have read "The Origin of Species." If they had read it, then they probably wouldn't be making the same arguments that they made in the 1850s -- after all, those so-called mysteries and problems that they complain about, are exactly what Darwin's theory of natural selection is made to explain.

So I'll give you a quick outline. First of all, notice that all individuals are different. In particular, children are not exactly the same as their parents, or even their parents' parents. But at the same time, they do share some characteristics.

Farmers have known for hundreds of years that you can take advantage of this fact, and get better animals in each generation, simply by breeding only the best ones from the previous generation. This is called artificial selection.

The second thing to notice is that all animals breed faster than they need to in order to maintain a constant population. One mathematical consequence of this is that any given kind of animal would fill the earth shoulder-to-shoulder if it were allowed to breed at its normal rate and all of the children were to survive. In other words, some of the animals die before they can make a "normal" number of babies. From the point of view of the next generation, that just means that some of them make a smaller contribution to the characteristics of the next generation. And this is called natural selection.

There's just one difference between natural selection and artificial selection. Farmers artificially select the best individuals; whichever look better, or run faster, or have tastier meat, or whatever. In absence of farmers, Nature does not select the best individuals according to any particular rule. Nevertheless, some of them live long enough to make babies, and some don't; the ones that make lots of babies are called the "fittest" ones, and they are the ones whose characteristics "survive". Hence, survival of the fittest.

Survival of the fittest does not mean that the weak ones get killed off by natural selection. It means that the fittest ones -- who can be identified by the fact that they are alive, and having babies -- survive in the next generation. And that means that the characteristics of the fittest ones will survive in the next generation. At least more so than the competition. Over time, this has the inevitable consequence that the population evolves.

I hope that clears up any misunderstandings left by your public school teachers.