The authors of a study of fishing villages in Finland between 1760 and 1849 argue that their data shows that humans are still evolving. For example, almost half of the people in the villages died before the age of 15, and of those that survived, one in five did not have any children. Therefore, they argued, the selection process driving evolution was present.But at face value, the logic of the team from the Institute for Advanced Study Berlin seems to be this:
1. some people did not have children
2. evolution requires that some individuals don’t have children
3. therefore, evolution was occurring.
Is that logic okay? The missing piece of the puzzle is that genetic variation must be contributing to people either dying young or not breeding. The researchers haven’t demonstrated that, they’ve assumed it. The case isn’t made by just showing variability in reproduction. There is always such variability. But while the conclusion might not follow from the data, Courtiol and his team are almost certainly right. There may be no proof that genetics had an impact, but it’s hard to see how it could be any other way. It’s implausible that genetics isn’t playing at least some role, whether in infant mortality, susceptibility to disease, overall fitness, attractiveness to the opposite sex, and so on.
And what is true for fishing villages is true for the rest of humanity. The idea, promoted by some theorists who should know better, that human evolution has stopped – or at least is on ‘Pause’ – has never been a credible one. Evolution, like gravity, doesn’t stop.
The question isn’t “are we as a species still evolving?” because we undoubtedly are. The interesting question is what forces are driving our evolution, and what direction are they taking us. The factors driving human evolution in modern societies are likely to be different to the dominant factors in a pre-industrial Finnish fishing village.
