In a recent op-ed piece for the New York Times, British geneticist J. S. Jones asked a provocative question: Has the human species stopped evolving? Are the glory days, when it seemed we were always coming up with something new--opposable thumbs, bigger brains, upright posture-- gone forever? Or will we continue to evolve?
Jones doesn’t think we will. He rightly points out that we’ll never become creatures with either X-ray vision or computers for brains. There is no evolutionary pressure for us to do so--our technology already provides doctors and airport inspectors with X-ray vision, and it may not be long before computers are hooked up to the human brain. In fact, he suggests, the strong pressure applied by natural selection during the evolution of our species has all but vanished. Natural selection once ensured that only the fittest survived and reproduced. Now almost everyone in the industrialized Western world can grow up to have children.
But this does not mean that natural selection no longer operates in humans. True, it may have slackened slightly in the lucky groups Jones talks about, but at most this easing has lasted for less than a hundred years. This is almost no time at all when you realize that the human species has existed for somewhere between 50,000 and 100,000 years and that our prehuman ancestors were evolving for millions of years before that.
