Chimps are not more evolved than humans or anyone else.

I like New Scientist. I even did a short interview with them about a cool genomics story (“How chemicals can speed up evolution“, 6 May 2006, p.16). But this headline from their news service really annoys me: Chimps ‘more evolved’ than humans.

The short news article starts out with “It is time to stop thinking we are the pinnacle of evolutionary success…”, which of course is true except that it was time to stop thinking this 150 years ago, and then continues with “… chimpanzees are the more highly evolved species, according to new research”.

What they mean is that, based on the recent study, it appears that the rate of fixation by selection of mutations apparently has been higher in the lineage that has led to chimpanzees than in the lineage that has led to humans since they split from a common ancestor several million years ago. Which lineage experienced the changes can now be inferred by comparison with the macaque genome, which is less closely related to chimps and humans than the latter two are to each other; without such an external comparison, one can not say which lineage had changed, only that one or both of them had. Most likely, this boils down to differences in long-term historical population sizes in the two lineages (selection is stronger in large populations, genetic drift in small populations).

Couching this interesting finding in terms of who is “more evolved” than whom is not helpful, even with the scare quotes. As someone who teaches evolution at the upper-year undergraduate level, I can tell you that students come into the class with a lot of preconceptions about evolution, one of them being the notion that some extant species can be ranked as “more evolved” than others. It is subtle misinformation like this, compounded over many years, that makes my job harder by the time they arrive in my course.

Please, please, PLEASE stop appealing to common misconceptions about evolution in news stories, even if the headline will catch the attention of (previously misinformed) readers.