In a recent bold statement, British geneticists Steve Jones said that human evolution has come to an end. He puts it down to 3 basic facts:
- Older men are having fewer children (older men have more mutated sperm, so this influences the mutation rate)
- A vast majority of people are living to reproduce (not dying before they can reproduce like the "good old days of low life expectancy")
- Small populations that don't mix is pretty much a thing of the past, spreading out genes and "averaging" everyone out
All of his points are correct - all of these things are true. Yet, why would he reach a conclusion like that? I don't exactly know.
Firstly, even according to his own words, mutation rates have lowered, not disappeared, so even according to his own facts, evolution has slowed down, not stopped.
Also, as someone who has played with genetic algorithms, I know that selection, not mutation is the driving force behind evolution. Has selection stopped?
Jones would say yes, since people aren't dying early like they used to. However, dying before reproduction is only one part of selection - there is another part: How do we choose mates?
People are very picky (even after taking alcohol into account) - what kind of things do people like in a mate? Both men and women have strong feelings about who they would pick to have children with.
I have no doubt that human evolution is proceeding in complete ignorance of what Dr. Jones concludes. No doubt, in a few years, the idea that human evolution has stopped will be look at like an earth centered universe.