Looking for the Real Evidence

In the case of the television series "Evolution," airing next week on public television stations nationwide, assumptions take the place of knowledge -- and truth suffers. Consider Tuesday's episode entitled "Great Transformations." According to PBS, "Great Transformations" asks the question, "What caused the incredible diversity of life on Earth, and how have complex life forms, including humans, evolved?" Well, to ask how something happens is to ask for its actual mechanism. If one can't provide evidence for that mechanism, it's reasonable to conclude that one doesn't really know how the process occurs. No amount of other information, no matter how interesting, can make up for the missing knowledge. Keep that fact in mind as you watch "Great Transformations." You'll see a lot of fascinating information, like fossil whales, extinct amphibians, interviews with scientists, and new discoveries about development. But what you won't see is evidence for the mechanism of macroevolution. You won't see the answer to the critical "how" question -- the answer Darwin thought he provided with his theory of random variation and natural selection. You won't see the evidence, because no one knows how macroevolution would occur - or, of course, if it ever does. "Great Transformations" talks a lot about the discovery of so-called "master control genes" in development, and features interviews with some of the scientists involved in these discoveries. In one of the most amazing discoveries in biological history, scientists have found that organisms as different as fruit flies and mice use many of the same genes to regulate their development. But is that evidence for undirected evolution, or for intelligent design? Here's where you need to watch very closely -- and to keep your critical radar finely tuned. Neo-Darwinism as shown on PBS claims that random mutations to these "master control genes" can modify development and thus change the body plans of organisms as macroevolution requires. Yet what the program actually shows when it depicts these mutations is highly misleading. It's possible in a laboratory to damage the developmental control genes in fruit flies, for instance, and cause legs to grow in place of antennae or cause an extra pair of wings to grow. But these flies are then helpless cripples that couldn't survive outside the lab. The four-winged fly couldn't fly because the extra pair of wings lacks muscles. And no healthy fly would mate with a mutant with legs growing out of its head. These macromutations shown on PBS do not survive in real life, only under laboratory conditions. And evolutionary biologists know this. Geneticist David Stern of Cambridge University wrote recently that "one of the oldest problems in evolutionary biology remains largely unsolved" -- namely, the problem of how macroevolution occurs. After next Tuesday, the public still won't know how macroevolution occurs. So what can we do? Call your local PBS affiliate and tell them you want to hear the other side of this debate. And call your representatives and tell them that public funding requires fairness in public broadcasting. References Lawrence, Peter. The Making of a Fly. London: Blackwell Science, 1995. Stern, David L. "Perspective: Evolutionary Developmental Biology and the Problem of Variation." Evolution 54 (2000):1079-1091.

09/21/01