The Three-Legged Woman and Other Excursions in Teaching

What Hath Darwin Wrought?

p p p p p p p p p p p p p p p p p whathathdarwinwrought? Once, while reading the graffiti in a stall in the men’s room at my college, I came across the following scrawl: darwin was wrong! I immediately realized that I had inspired this wisdom, as I had just that very morning broached the topic of evolution in my introductory biology course, during which a woman in the back row quietly seethed as I pressed inexorably onward with the incendiary material. I tried to erase the comment by spitting on my thumb and rubbing it, but the marker was of the indelible type. The symbolism forbidden fruits 110 p f o r b i d d e n f r u i t s wasn’t lost on me: of all the world’s nations, the United States is touted as being the most technologically advanced, yet the idea of evolution—accepted without a whimper in even Third World backwaters—is still fodder for controversy here. Like the graffito in that stall, it just won’t go away. In 1999, for example— long after the Scopes trial was thought to have been the final catharsis in the battle to “allow” evolution to be taught in American public schools—the Kansas Board of Education voted to “reject evolution as a scientific principle.” It seems trite, at this juncture in the ongoing battle, to ask, “Why should this be?” The answer is no secret: religious fundamentalism . This was encapsulated for me in a very direct and personal way when that seething woman in my class decided to take action. At the conclusion of my lecture, she marched up to me and, with fire in her eyes and a raised, accusing finger, declaimed the following: “For what you have taught today you shall be damned to the everlasting fires of hell.” So. After a moment’s pause, I gave her the only answer that seemed appropriate: “We never learned anything we weren’t meant to know.” It helped a little. She took a step back and examined me with a cold eye. “How can you speak so glibly about a theory that’s not even true?” she demanded. A theory? I once saw a cartoon that said it best: Evolution may have started out as a theory, but it evolved into a fact a long time ago. Still, the expression “theory of evolution” is so well grounded that even many scientists unconsciously utter it. Evolution is not a theory. We know that the earth’s environment has been changing constantly since the planet’s origin. Maine, for example, was once tropical (during the Cretaceous Period, more than sixty-five million years ago). We also know that, if a species population is to survive, it must, over time, adapt to its ever-changing environment or else it will go the way of the dodo. If Florida were to embark upon a long-term (hundreds or What Hath Darwin Wrought? p 111 thousands of years) chilling trend, does anyone really believe that palm trees would persist in their present form? Something, in short, would have to give. The heartiest palm trees would have the best chance of surviving the creeping cold, and they would therefore pass their “cold resistance” genes on to their offspring. In time, these palms would change so much that they would become a type of tree—a new species—that could survive the frostier climate that would come to characterize Florida. What I have just described is the mechanism by which evolution works. It’s called Natural Selection, and it is this that is the theoretical part of evolution. Natural Selection was the long-suffering, hypochondriacal Charles Darwin’s brilliant idea, and virtually all mainstream scientists accept at least its broad assertions. There are other theories of the fact of evolution as well. Some have been discredited, such as Jean Baptiste LaMarck’s eighteenth-century idea of “use and disuse,” which states that if an individual “needs” a change in its body, it acquires this change and passes it on to its offspring (that is, if a monkey stretches its arms they will get longer, and the monkey will then have longarmed babies). Other ideas have complemented or even competed with Darwin ’s theory of natural selection. An example is the theory of “punctuated equilibrium,” postulated by the paleontologist Niles Eldredge and...