A comment on the Gansus find

An AP story this morning discusses a new fossil find in China of an early bird, Gansus, from about 100 million years ago. The headline reads “Bird fossils in China called a missing link in evolution.”

Now this is a neat find, and I urge you to read the story, but I’d like to discuss the headline as an example of the way the popular press mischaracterizes science sometimes, and adds to public misconceptions about evolution.

For example, a fairly typical response has occurred over at Uncommon Descent, where one of Dembski’s blogging group writes, “I guess I just don’t get it. Why has the missing link in bird evolution just been found, when I have been assured for years that there is overwhelming evidence in the fossil record that the enigma of bird evolution was already solved?”

One of the problems with press stories about science is that most of the time they add a “hook” about the significance of the story that is misleading in some way. In particular, the phrase “missing link” implies the mistaken idea that certain kinds of creatures have some special transitional status. But that is not true. Every fossil find is a link between earlier and later creatures, and they are all missing until they are found. The phrase “missing link” implies, especially to that part of the public that has doubts about evolution, that somehow the particular find in question is of a special creature whose existence somehow now “proves evolution.”

This is exceedingly simplistic: no one in science has ever claimed that “the enigma of bird evolution”, or any other aspect of evolution, has been “solved”; nor does anyone in science believe that any one find will “prove” evolution. The fact that evolution has occurred has been established by the accumulation of many, many thousands of pieces of individual evidence, of which this find is just one more.

One of the significant things here, is that Gansus, like the earlier find this year of Tiktaalik roseae, was found at the time and in the place that we would have expected, based on what we know already about bird evolution. In that sense it is a piece of the puzzle that fits in the right place: it is not a “rabbit in the Cambrian.”

Notice what the article says,

“Most of the ancestors of birds from the age of dinosaurs are members of groups that died out and left no modern descendants. But Gansus led to modern birds, so it’s a link between primitive birds and those we see today,” Lamanna, a co-leader of the research team, said in a telephone interview.

Previously there was a gap between ancient and modern species of birds, and “Gansus fits perfectly into this gap,” added Jerald D. Harris of Dixie State College in Utah.

In the “Evolution 101” class I gave last April, a two-evening talk to the layperson about evolution, I emphasized that we should stop using phrases like “missing link” because of the misconceptions it engenders. Notice the two quotes above: Lamanna simply says “it’s a link”, not a “missing link”: good for him. Harris says, “There was a gap between ancient and modern species …”. If might have been better (and I am not faulting Harris, because I know that newspaper reporters respond best to brevity) if he had said “there was a gap in our knowledge of ancient and modern species …” This would have made it clear that what is in doubt about this or any other evolutionary problem is the details about what happened, not whether evolution happened.