Where Is Human Evolution Heading?

Don't forget, for evolution to work, 2 things must happen - genes must mutate, and the mutated genes must lead to more offspring than average. I question the latter - more likely, as in Cyril Kornbluth's "Marching Moron" stories, we are breeding a surplus of welfare-prone less-adept underclass. The rich and smart are having even fewer children. The population of some first-world countries is shrinking, for demographic reasons; if you are comfortable middle class, a child is a burden.

The other possibility, as alluded to with the autism suggestion, is that we are morphing into a split race - rarely until now has each social class been so likely to marry within its group; while our meritocracy allows the smart and capable to rise up into their appropriate class. We are stratifying, perhaps, like H.G. Wells' Eloi and Morlocks?

Yes, the factors are positively greater for more evolution. We have a huge gene pool - 6 billion - with more chemicals and other factors causing alterations to the gene pool. The unprecedented scale of travel and migration means a much bigger mixing of the pool. The downside, is that human nature has not changed. People reproduce for the wrong reasons; more likely for neglecting birth control than for attraction or desirable traits. (Not every mother is gorgeous or a fine mammary specimen, for example; fathers ditto). Modern medicine helps prevent all but the more egregious genetic problems being eliminated from the pool; bad eyesight will not get you killed the way it could in the Serengeti. The evlutionary processes mean there is a wider variety of humanity, but it is not selecting.

I also question the "genetic" component. AIDS is not more survivable because of human genetics; more likely, disease's genetics. What we see is common of all diseases. The first bubonic plague killed 30%-50% of Europe. Subsequent waves, significantly less. The virulence drops because the deadliest germs or virus fail to make it to as many hosts, once the danger is understood. The moderately infectious diseases spread the farthest.

Also, perhaps some things are simply not genetic. I suspect that most brain-destroying conditions - autism, parkinsons, alzheimers, etc. - are a virus that eats the brain. It randomly pops up to do damage in some individuals. Once a certain amount of damage is done, the brain no longer can compensate, and the symptoms appear. I go even further, and blame a disease for diabetes I, heart attacks, arthritis, etc. Consider clogging arteries; the clots in the arteries build on something. Stents and balloons have limited effect, blockages regrow; sometimes, a person becomes cured. Only 20 years ago, ulcers were considered psychological; now we treat them with antibiotics.

After a billion years of evolution, the body still gets diseases. At least that proves a lack of intelligent design.

MD 2:29PM July 25, 2008