大象传媒

Some scientists now believe that human evolution has ceased, we are as advanced as we're ever going to get. We have become so clever at adapting our environment to suit our needs that we no longer need to evolve; we simply invent tools to do new tasks for us.

However this is not the only view. Others point out that there are many parts of the world where man cannot fully control external influences. The most noticeable of these is disease pandemics such as plague or malaria. Over millennia humans have adapted to disease and genetic resistance has appeared in some populations. Perhaps the most well known is the genetic mutation which confers resistance to malaria but also leads to sickle cell anaemia.

Peter Evans this week asks whether this process of adapting to disease is still going on and explores some new findings which have wide reaching implications for classical evolutionary theory.

There is direct evidence that humans are developing an evolutionary response to HIV, just as chimpanzees developed resistance to Simian IV thousands of years ago. Another factor which could be determining our evolution is the influence of society - could our lifestyles affect our abilities to reproduce?

In the industrialised world we are having children later, and seem to have more problems with fertility. And overall we're having fewer offspring - in the long term this may affect human survival. There is now evidence that our fertility, and therefore our chances of reproducing, and thereby passing on our genes, is being influenced by our diet, particularly where obesity is concerned. We can now manipulate our genes but should we?

And if we are still evolving, into what are we evolving? Some theorists suggest we are becoming super-beings; others present a less positive scenario in which we develop into weaker smaller animals which cannot function properly without our manmade toys.