Many of today's paleontologists say birds are dinosaurs—specifically, the surviving members of a group called theropods. But is it true? Alan Feduccia, an ornithologist and evolutionary biologist at the University of North Carolina at Chapel Hill, doesn't think so. He and a handful of other skeptics argue that birds evolved from an early dinosaur ancestor, making them only slightly closer relatives of T. rex than lizards are. Feduccia shared his views with Discover associate editor Kathy A. Svitil.
Why don't you think birds are descended from dinosaurs? First, the time line is all wrong. These alleged dinosaurian ancestors of birds occur 25 million to 80 million years after Archaeopteryx, the earliest known bird. Second, by the time you get to dinosaurs, you are dealing with fairly large, earthbound creatures, which means they would have had to evolve flight from the ground up, rather than from the trees down. Evolving flight from the ground up is biophysically implausible.
Third, many of the features of birds and dinosaurs—the hands and teeth for example—don't match. The theropod dinosaur hand consists of the thumb and the next two fingers. The bird hand is made up of the middle three fingers. You can't just flip a switch to go from one type of hand to the other. Of course, it doesn't matter what line of evidence you come up with, you are automatically wrong if it is anything contrary to the dinosaurian origins of birds.
