Are We Still Evolving?

I recenlty read an amazing article in Seed on Evolution. Here are the highlights:

Humans "showed up" 45,000 years ago and it doesn't appear that we've changed much in those years. It's easy to make that assumption since natural selection chooses the most fit to survive through reproductive success; the problem however is that we nurse our sick back to health. Mating isn't a privilege so even the less fit pass their genes on. Well the Human Genome and HapMap projects are changing what we know about how we're evolving. It appears that up to 10 % of the human genome appears to be evolving, but most mutations have a neutral effect, making them neither fitter or less fit. The HapMap project has found gene variations in some populations that were not present in other geographic areas, but are moving over time proving that genetic drift is occuring.

One of the best examples of recent human evolution is the spread of the mutation for adults who can digest milk. It popped up 8,000 years ago and has spread to most parts of the world, but not all, only 9 of 10 Asian Americans lack the mutation. Hawkes, an anthropolist studying demography and the constraints on our adaptation believes that the global population explosion that coincided w/ the agricultural revolution is the main driver of adaptive evolution. He exclaims that our world has changed rapidly and our DNA is still catching up. Hapmap has provided great insight because it lets us compare parts of the human genome that are different between people; it gives us a glipse at patterns of gene inheritance.

So now for the question at large: Are we getting smarter?

Several different studies have been conducted on the topic. Bruce Lahn an evolutionary geneticist raised some controversial issues because his work could easily be misinterpreted as claiming that brain evolution has occurred in some races but not others. The fact is we know very little about brain evolution and it's difficult to understand how intelligence is selected for. Here is one of his most interesting thoughts about the possibility of the evolution of intelligence: "500 million years ago earth experienced the Cambrian explosion, a rapid increase in diversification of life forms. It may take a long time to evolve certain components, but once you have them, very little evolutionary time could give you great diversity. The brain may take a long time to get to a certain level of intelligence and then, once it's there, it makes possible a cultural explosion."

He goes on to say intelligence builds on intelligence, increasing intelligence, increases the complexity of culture, which pressures intelligence levels to rise, which creates more complex culture and so on.

I'm fascinated by the way humans are evolving and becoming more intelligent. It's clear that some people are smarter than others; but that is somewhat of a subjective statement since there's mathematical intelligence, emotional intelligence, creative intelligence, etc. If we follow Lahn's theory it could be possible that these intelligences are merging. In this way maybe we are moving toward another explosion where the brain becomes able to do exponentially more than it has been. Time will tell.