Friday 12 May 2006

Pic of the day: This screenshot from the anime Kage Kara Mamoru is highly relevant to today's rather serious essay. You'll see eventually.

Recent evolution

"Recent evolution" is a minefield topic even among the educated people who accept evolution as a scientific fact. It is far easier to pretend that humans stopped evolving before our last common ancestor, and that all later variation is simply random or cosmetic. The reason is of course that if we accept more recent evolution, we will have to conclude that some humans are "more evolved" than others. Since this is a value term (more evolved = better) we are skirting very close to ideologies that have set the world in flames in the 20eth century. If recent evolution is a truth, it is tempting to ask whether it may not be a bad truth that should rather stay hidden.

The question is particularly pressing for the USA. In its past lies the dark horror of black slavery, justified with the claims that the blacks were less human than whites and not capable of independent thought. Even after slavery was abolished, blacks continued to be treated as second-class citizens in much of the country. Even in fairly modern times, after America was instrumental in defeating the racist horror of Hitler's Germany, many white Americans continued to view their black neighbors as inferior. Lately this has been tied to studies showing that African-Americans are on average somewhat less intelligent, but stronger. Strangely there is less focus on the same studies showing Asian-Americans to be on average more intelligent than whites...

In reality, the variation within ethnic groups is far greater, and perhaps especially the genetic component, the part that is not explained from living conditions and cultural traditions. And the debate seems to ignore all other forms of evolution. But recent studies of the human genome indicates that there are at least 700 parts of it that are still evolving, or have done so after the invention of agriculture some 10 000 years ago. Local populations have adapted to the local diet, becoming better at digesting and metabolizing certain foodstuffs. In addition, it would seem that local standards of beauty have influenced both skin color and details in the skeleton. The immune system is also undergoing intense evolutionary pressure, as we meet ever more diseases from all over the world.

Now ask yourself: Is someone who can drink milk more or less evolved than someone who can eat beans? Is resistance to frostbite more or less evolved than resistance to skin cancer? How about malaria vs HIV? Are tall people more evolved than short people? Are thin eyebrows more evolved than thick?

Yes, studies show conclusively that on average, taller people earn more than shorter people with the same education. This goes for both men and women. Tall men are also rated as more romantically attractive. These are clearly indicators of evolution in action, and unsurprisingly the average height has been increasing for quite a while now. But we don't classify people into "races" based on their height, like we do with their skin color.

But surely brain size and IQ are the true indicators of how evolved we are. After all, it is our brain that sets us apart from the apes and other unfortunate animals, right? Well, it sure does. (Though it does not set us apart from the dolphins, who have comparable and sometimes larger brains relative to body size.)

But how about body hair? It certainly sets us apart from the other apes, and seems likely to have been a strong factor in keeping our species separate from others. The renowned primatologist Desmond Morris even chose to call humans "the naked ape" in the book of the same name, which was the first popular attempt to look at humans as mammals rather than just as souls with an unfortunate fleshy appendage called body. Strangely enough, though, many Europeans (including yours truly) are hairy to an extent that would cause revulsion among inhabitants of other continents. Not a few of us are proud of it too. "To have hair on one's chest" is considered an honor. But in an evolutionary perspective, the least hairy – and thus most evolved – humans are Africans.

Another particular human trait is the enlarged buttocks. Originally the muscles, gluteus maximus especially, grew to accommodate walking and standing upright. This distinctive human feature soon took on a species- defining role and became an important selector. Until this very day, both women and (especially) men pay particular attention to this part of the body before mating. One would therefore assume that the "race" with the most developed buttocks would be the more evolved. This happens to be the "bushmen" of South Africa, with some other African populations taking a clear second place, far ahead of the rest of mankind.

And let us not forget a rather pointless but glaring example of sexual selection in its most narrow sense: The male reproductive organ of Homo Sapiens is several times larger, even compared to the body mass, than any other primate. Based on this, one would expect that the most evolved human population would have the lead also in this area. I probably don't need to tell you where these can be found... again.

On the other hand, the perhaps single most striking trait of our species is its neoteny, that is to say, childlike traits being preserved into adult (reproductive) life phase. (Actually a more accurate description is "pedomorphism", but neoteny has reached wide use in popular science.) A human baby and an ape baby are amazingly similar. But an adult human still looks a lot like the baby, while an adult ape looks very different. Based on this, the most evolved humans should look more childlike in their adult years. I am sure most East Asians would readily agree with this... for several years of their adult life, the average Asian looks like westerners do during puberty.

In short, there is very little to support the idea that the British and their descendants are the crown of creation, the pinnacle of human development and our last best hope for the future. Sorry about that. Perhaps they just were lucky and found a good language? Because in our age and time, I think we must accept that cultural evolution is more important than biological evolution. That doesn't mean the latter does not exist. There is actually far more of it than we thought, and humans may be among the fastest mutating species today. But for the fate of the species, the local population, and indeed the individual, culture reigns supreme.

Of course, you do need some brainpower to fully participate in today's advanced cultures. And so there are limits to how stupid you can be and still be attractive. (Although some men seem to disagree with me on this, disturbingly.) Perhaps in the long run the evolution of the brain will be the most important, after all. But so far, it seems to me that most don't even fully use the brain they have. And in the end, it may influence your job decisions but hardly your worth as a human. Today, more than 6 billion humans are less intelligent than I. A strategically placed banana peel might reverse this. Is my worth as a human really so fragile a thing? I'd like to think not.