Saturday 17 December 2005

Pic of the day: Japanese artist's impression of a sexy man. But it's a safe bet this is nothing like the...

Sexiest man ever!

No, I'm not talking about myself. The guy in question lived somewhere between 60 000 and 90 000 years ago, at a time when there were few humans in the world. In fact, one recent theory says that after a "one in a million year" volcano explosion around that time, only a couple thousand humans survived. Certainly humans were fairly scarce, but they did get around. And one of them was the world's sexiest man.

We know this for the simple reason that he is the ancestor of us all. At least all Y chromosomes that have been analyzed so far seem to come from this one guy. Notice that the mitochondrial DNA, which is inherited solely from the mother, goes back quite a bit longer, roughly 150 000 years (again, give or take a few tens of thousands of years). So Eve lived something like 50-100 000 years before Adam. But all of her female descendants at one time had children exclusively with Adam and his descendants. He must have had some trait, which was inherited by his sons, that made them irresistible to women.

Some people think this trait was creativity. It has generally been assumed that art and language emerged as a package during the great leap that suddenly spread through all human populations 60-40 000 years ago. Almost overnight, at least in a geological perspective, humanity's character changed. The earlier humans, the sons and daughters of Eve, had at least as big brains as we; their contemporaries to the north, the Neanderthals, even had larger. But the offspring of Eve were identical to us in every way that can be read out of a skeleton. They just didn't have any art, and their stone tools were just more professionally executed versions of the stone flakes used for two million years. Until the revolution. Or... until Adam?

The speed by which creativity spread seems to indicate that it was cultural rather than genetic. Recent finds of beads and colors from Africa dating back to perhaps 90 000 years ago are few and scattered, and while there are also refined tools from before the "revolution", they are once again local and isolated in time and space. As if the occasional genius lived and transformed their tribe, but never thought of bringing the light to the world.

It is possible that even if culture and genes did arise separately, they may have worked together. We know for sure now that all humans now alive descend from African ancestors; the genetic variation is so much larger in Africa (especially East and South) that it seems clear only a subset of them wandered out and colonized the rest of the world. At this time Adam must already have lived and done his magic, because it seems unlikely that his descendants later can have combed the whole world and found absolutely all women on every continent and island. Both in Africa and among the exiles, only his descendants survived to our day.

***

We will probably never know how the pre-Adamite men were. Not what they looked like, nor how they acted. What we know is that they simply could not hold a candle to the man as we know him. Their skeletons look exactly like ours, but of course there are other body parts that are not preserved in stone, and there may have been differences. Most e-mail recipients can probably think of one such example. But paleo- anthropologists generally think it was a behavioral traits. Of course, paleo-anthropologists are generally nerds, so may be disastrously wrong in this. It is a fact that human males today really stand out among primates, even the great apes, by one more thing than their brains...

Excavations from the last Neanderthal sites seem to imply that the men lived apart from the women and children for the most part. It is quite possible that pre-Adamite men did the same. If so, the big difference may be that Adam cleaved to his wife, as the good book says, that is to say he stuck around. It is a known fact that humans are more childlike than apes, and every species that we domesticate thoroughly (dogs in particular, who came way early) evolve to become more childlike. So women may have a soft spot for this. Children obviously follow you around and don't like to be apart for weeks at a time. If Adam and his sons were just as clingy, they may have had a lot more opportunities to procreate than their more roaming cousins. More than just being at the right place at the right time, it may even be that this juvenile behavior has endeared them to the females.

Those last parts are just random speculations I have thought of. I am sure others have already come up with other theories, and it will be a long time before we can find an answer, if ever. The simple reason for this is that, as far as we know, not one single pre-Adamite man has survived. Adam and his sons won hands down. I am not sure it could happen again, but who knows? It certainly won't be me, though. More's the pity for mankind... ^_^