Tuesday, February 17, 2009
The evolution of evolution
OK, so I'm a little behind the times. I wanted to wish Charles Darwin a happy birthday last week, but life got in the way. While we extol the virtues of Darwin and his theory of evolution, I want to talk a little bit about another theory of evolution, that of Jean-Baptiste Lamarck.
The Lamarckian theory of evolution states that acquired traits can be inherited. The classic example is the long neck of the giraffe. Lamarck's explanation would be that as giraffes stretch up to eat the leaves of trees, their necks become longer and stronger. Their offspring would then have long necks. The Darwinian explanation would be that those giraffes with genetically determined longer necks would be better able to reach the leaves up in the trees, and thus better able to survive and produce offspring, passing along their long-neck genes to their young.
The more recent field of epigenetics is lending some credence to Lamarck's ideas. Recently published papers in Biological Psychiatry and The Journal of Neuroscience show that experience can alter certain traits in mice and that these traits can be inherited.
I'm not saying that Darwin was wrong, or that giraffes owe their necks to stretching instead of genes. Like any scientific theory, Darwin's theory of evolution has evolved and will continue to evolve as new information is obtained. It doesn't invalidate the theory. It just makes it more elegant.