Wednesday, June 15, 2005
Who Says Lamarck Is Dead?
A while ago, I linked to an article postulating that weakening of the jaw muscle in early hominids allowed for the explosive brain growth we've seen over the last couple million years. Today, Boingboing points out an article arguing that our brains got bigger to coordinate the various new things we had to do - like throwing rocks and navigating complicated social networks.
While this is certainly an interesting idea, I take serious issue with it for two main reasons. First, it's well established that bigger brains are not necessarily better, at least after a certain point. Second, and more important, is that this is not scientific logic. If a human who happened to have a bigger or more effective brain that allowed him to throw rocks or navigate his neighbors better, and that bestowed him a survival advantage, the 'big-brain' genes would thrive. Traits exist and are selected for or against by the environment, an organism's needs do not shape its evolution.
While this is certainly an interesting idea, I take serious issue with it for two main reasons. First, it's well established that bigger brains are not necessarily better, at least after a certain point. Second, and more important, is that this is not scientific logic. If a human who happened to have a bigger or more effective brain that allowed him to throw rocks or navigate his neighbors better, and that bestowed him a survival advantage, the 'big-brain' genes would thrive. Traits exist and are selected for or against by the environment, an organism's needs do not shape its evolution.
