August 25, 2009

Study challenges Darwin’s appendix theory

Scientists at the Duke University Medical Center say they've conducted the first study of the appendix through the ages and conclude Darwin was wrong.

Duke scientists and collaborators from the University of Arizona and Arizona State University conclude Charles Darwin was wrong when he called the appendix a vestigial organ. The researchers said not only does the appendix appear in nature much more frequently than previously acknowledged, but it's been around much longer than anyone had suspected.

Darwin theorized the appendix in humans and other primates was the evolutionary remains of a larger structure, called a cecum, which was used by now-extinct ancestors for digesting food.

But the new study found several living species, including certain lemurs, several rodents and a type of flying squirrel, still have an appendix attached to a large cecum that's used in digestion. And the researchers also found the appendix is quite widespread in nature.

Darwin simply didn't have access to the information we have, Assistant Professor William Parker, the study's senior author, said. If Darwin had been aware of the species that have an appendix attached to a large cecum, and if he had known about the widespread nature of the appendix, he probably would not have thought of the appendix as a vestige of evolution.

The research is detailed in the Journal of Evolutionary Biology.