Dinosaur to Bird

    Once again, a fossil has made the headlines. The New York Times even put the story on Page One, above the fold. Why all the excitement? Well, the fossil, a so- called "feathered dinosaur" found in northeastern China, appeared to provide strong support for the theory that birds evolved from dinosaurs. Well, how about a short exercise in critical thinking? Let's apply some skeptical analysis to the scientists' claims, to see what we can learn about separating fact from theory. First, unlike the last feathered-dinosaur "discovery" -- which turned out to be a hoax, embarrassing the National Geographic Society -- this fossil appears genuine. About the size of a duck, the fossil belongs to a group of dinosaurs called dromaeosaurs. What's remarkable about this new fossil is its downy covering -- including some structures that appear to resemble feathers. Well those are the facts, but there's one more rather important piece of data you may not have seen in the Times. It was found in geological formations in China dated to 125-130 million years ago. Now, why is that important? Well, according to the standard dating of paleontologists, the earliest-known bird, Archaeopteryx, is actually much older than that: almost 20 million years older, in fact. But if dromaeosaurs were more primitive than the creature long thought to be the first bird, how can they show up 15 to 20 million years later in the fossil record? How could one bird live earlier than its grandmother? Here's where theory trumps evidence. The evolutionary biologists who advocate the dinosaur-to-bird story say that the geological time sequence doesn't matter. Paleontologist Henry Gee, for instance, admits that "it seems odd, even outrageous, to claim that birds such as Archaeopteryx descended from dromeaosaurs." The fossil is wrong, in other words. But, so what? Gee shrugs off the problem. He says that "stratigraphic order" -- namely, the geological sequence in which fossils appear -- "is no barrier to any possible hypothesis of relationship." Dino-to-bird advocates like Gee start with the assumption that birds evolved from non-birds. So the only question is, What group of non-birds looks most like birds? Dromeaosaurs are the leading candidates, despite the fact that they occur too late in the fossil record. If evolutionary theory tells you to look for someone to play the role of grandma, it doesn't seem to matter if she turns up millions of generations later than her grandchildren. And you see, that's precisely the problem. Skeptic ought to ask, What's really behind this dino- to-bird theory? If scientists can just step over an issue like stratigraphic order, we have to wonder what other difficulties are being shoved aside. And there are many such difficulties. A vocal minority of evolutionary biologists completely reject the dino-to-bird theory, because they find it implausible that ground-dwelling creatures like dromaeosaurs could ever evolve the behaviors and structures needed for flight. So what's the moral in all this? We need to dig into the details whenever we hear claims about "proof" of naturalistic evolution. Science can be an important tool, but science also needs skeptics to keep it honest. And so does the New York Times. For further reference: Gee, Henry. In Search of Deep Time: Beyond the Fossil Record to a New History of Life. New York: The Free Press, 1999; pp. 182-183. Padian, Kevin and Luis M. Chiappe. "The Origin and Early Evolution of Birds." Biological Reviews 73 (1998):1-42. Sues, Hans-Dieter. "Ruffling Feathers." Nature 410 (2001):1036-1037.

05/14/01