Phenotypic Plasticity


Only the lunatic fringe questions the reality of global warming! Why, Al Gore himself assures us that it is a fact, and a dangerous one. Would Al lie to us?

If we assume global warming to be a fact, the question then arises: how much warming has taken place? The answer seems to be that, in the past century, the temperature of the globe (!!?) has risen by about 1 degree Fahrenheit.

Now I daren’t doubt Mr. Gore, but, just between you and me, I question how anyone could come to that conclusion. As I’ve previously written, we have four outdoor thermometers located around our house, and they never read the same, and the differences are more than a degree. Which one approximates the temperature of the entire globe?

It was only in the mid 19th century that worldwide temperature measurements began to be accumulated, so the temperature rise of 1 degree in the past century doesn’t give us much basis for comparison, since only fifty years before the temperature began inching up, no worldwide temperatures were known.

I know that scientists tell us they can determine the temperature thousands of years ago by studying ice cores taken from the Arctic, among other methods, but I suspect that such determinations are based, at least in part, upon the results that the scientists wish to "discover." I suppose that "global warming" is where the grant money is!

But ancient temperatures aren’t involved with phenotypic plasticity! That very impressive phrase simply means, according to biology professor William Bradshaw, the "ability of individuals to modify their behavior, morphology, or physiology, in response to altered environmental conditions." I guess we simple folks could say that animals adapt to their environments. Is that a big deal?

Well, yes. Dr. Bradshaw’s colleague, Dr. Christine Holzapfel, warns us that some species of animals are changing genetically in order to adapt to rapid climate change. Small animals, which breed quickly, such as squirrels, insects, and some birds, are showing signs of evolving new patterns of behavior to increase their chances of survival. And, warns Dr. Holzapfel, "it is clear that unless the long-term magnitude of rapid changes is widely acknowledged and effective steps are taken to mitigate its effects, natural communities that we are familiar with will cease to exist." Wow!

I read somewhere recently that more than 95% of all species have become extinct. So I guess if we lose some squirrels and insects, we can live with it. What seems remarkable is that a change of about one degree over a century should trigger off this adaptation mechanism, which the scientists come very close to calling evolution. They don’t actually use that word, for very good reason: adaptation has nothing to do with evolution. That term, historically, means the appearance of a new species arising from an old one. It has never been observed to happen, and changes in the behavior of squirrels aren’t examples of evolution by any stretch of the imagination.

Drs. Bradshaw and Holzapfel are careful to point out that there is little evidence that genetic alterations are taking place in response to climate changes, yet Dr. Holzapfel assures us that "over the past several decades, rapid climate change has led to heritable, genetic changes in animal populations." Confused? Me, too. So what ARE they telling us? It seems that their message is that the response of animals to global warming may be extinction. However, as extinction is the fate of many, many species of animals, and happens regardless of global warming or cooling, to link that phenomenon with the highly dubious possibility of global warming seems a bit presumptuous. And what is the "rapid climate change" to which they refer? A degree or two a century?

The article by the two biologists, appearing in Science, suggests, at least to me, that global warming and evolution are working together to bring about alterations in animal populations. Except, of course, that global warming is an unproven (and unprovable?) hypothesis, evolution is not involved in mere adaptations, and extinction, which happens often enough, doesn’t require global warming. At its essence, the message seems to be that some species fail to adapt, and become extinct. Is that news? Is the sky falling yet?

Dr. Hein [send him mail] is a retired ophthalmologist in St. Louis, and the author of All Work & No Pay.

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