Monday, 5 September 2011

The End of Evolution

I lost a few friends one morning back in 1983. There was a debate about eugenics.
At the time I'd just broken up with my first proper girlfriend - a likeable enough girl, but who I didn't fancy and who I stayed with for two years because I was afraid no one else would have me. I was twenty-one.
Anyway - that's another story. Suffice it to say I was keen to make new friends and meet more women so when I met Chris Dance at work (with Brighton Parks and Gardens, picking the litter out of the municipal shrubs on the Whitehawk Estate) he seemed like exactly the type of guy to get me in there. He lived with a bunch of students in a shared house in Coleman Street, in the Hannover part of Brighton, north of Kemptown. He had travelled. He had a Swedish girlfriend. We went to see the Piranhas at what was then The Richmond (my first gig) and he introduced me to his house-mates and invited me along to one of their parties where we danced to the 12 inch versions of Dr Mabuse and Uncertain Smile. At the time it all seemed impossibly cool and trendy.

It was the following morning. We were all sitting around on the lounge floor in deep and meaningful conversation, and the subject of human evolution came up - about what we, the human race might look like in the future. As I recall the usual ideas came up - huge brains, puny little bodies, but then I piped up and said that wouldn't happen 'since everyone is allowed to breed these days'.
Things went very quiet after that. I was not invited back.

I'm not sure I realised what had happened at the time. I knew something had though. Somehow I'd blown it.
It was only much later I realised what it might have been.
At the time (and ever since) I was very interested in Evolution and Natural Selection. I tended toward the Stephen Jay-Gould end of the spectrum rather than the Richard Dawkins, but found the whole thing fascinating. I wasn't used to speaking up in public but on that occasion I felt qualified. Such nonsense people spout about evolution!
What I meant of course was that people were ‘allowed to breed’ in the same way as, for example, jet engines allow English people to spent the weekend in New York, or modern medicine allows people to live into their eighties. I didn't mean they were allowed legally or morally, and certainly not that I thought they shouldn't be allowed to breed, but that was how they took it, my new-found, right-on, politically correct, student teacher friends. If anything my view would have been (had they asked) that if we are no longer evolving, we should spend more on the NHS because of the increasingly unfit (in the Darwinian sense) population. I certainly wouldn't have been advocating eugenics. Quite the reverse.
If you're out there Chris, for the record, I wasn't a Neo-Nazi. Ok?

The idea that the human race is not evolving is hard to stomach for a lot of people though, but it's probably about right. For evolutionary changes to occur, genetically determined traits must affect the breeding success of their carriers. So for example, for the 'Big Head/Small Body' humans to evolve, people with big heads (and hence presumably big brains, hence greater intelligence) would have to leave more children than people with small brains. Likewise people with big strong bodies would have to leave fewer. As it stands, and without wanting be all elitist about it, the reverse seems to be the case. It's possible we're getting stupider rather than brighter.

I’ve given this some thought and it's hard in fact to think of any traits that have consistently lead to bigger families long enough to affect human evolution (except perhaps stupidity). I’d guess that those genes that tend to make us sick or disabled would tend to leave their carriers at a disadvantage but the more we are able to treat these inherited conditions, the more the carriers will be able to live ‘normal’ happy fulfilling lives and leave just as many descendants as everyone else, hence the increasing medical bill. Simple things like very premature babies and the kinds of complications that lead to caesarean section these days would have completely removed the genes that are associated with them from the gene-pool at birth. Now they don’t and to the extent that such complications are heritable, they are likely to increase. Does this mean that we should let these babies (and mothers) die in childbirth (as they would have until quite recently) for The Good of the Species? Obviously not, but we will probably have to provide more hospital beds and incubators as time goes on.
Disease resistance is another thing. Evolutionary biologists talk about the Red Queen hypothesis whereby “It takes all the running you can do to stay in one place”. The bulk of ordinary routine evolution does nothing but maintain the immune system - those without the requisite disease resistance being routinely eliminated leaving only those that do to pass on their genes. The immune system has to evolve to keep pace with the evolution of the pathogens, some of which, bacteria in particular, evolve very fast indeed. But to the extent that medical science can keep pace with the pathogens (with antibiotics etc) even this level of evolution is much less crucial than it would have been in earlier times and in other species. In any case it hardly changes our outward appearance (hence the ‘standing still’ part of the above quotation.)

Sexual selection is another possible source of rapid evolution – the classic example being the peacock’s tail – evolved in spite of being a liability in the hiding and running away department, it has reached its present proportions because the females liked it and selected the males with the biggest tails to have sex with. (It is probably an ‘honest signal’ of male fitness – only very fit males could get away with lugging that thing about in the jungle.)
Which human sexual characteristics have been consistently attractive over long enough periods of history to have affected our evolution? Men’s heights perhaps? Women’s breast size? Facial symmetry is often cited as particularly attractive to mates. Breast size is an interesting one because breasts don’t need to be anything like as big as they are, even in relatively modestly endowed women, merely to feed infants. Other mammals manage perfectly well with much smaller ones, so they’re probably as they are just to attract a mate. (This might cause offence to certain feminists but it is interesting that in most other showy species it’s the male that does all the showing off and looking amazing and the females stand about and choose. Humans are unusual in going for a much more even division of labour.) Penis size might be another one. Human penises (and presumably vaginas) are much bigger than other apes’ penises (and vaginas).
But generally it seems to me that what is considered attractive in men and women has varied so much through history and geography that it’s hard to come up with anything that has been so consistently and universally desirable that it might affect the look of the human race in anything but a very temporary and local way. Much of the increased overall average human size is probably mostly accounted for by improved diet, medicine and sanitation.
Psychological traits (to the extent that they are governed by genetics) are better candidates. Sociability, the ability to perform (in the sense of showing off – singing and dancing etc) or fight or be a good provider might be selected for but I see no particular improvement in any of this in the human race at large.

The reason for this ‘failure to evolve’ is in another characteristic of human society – the fact that sooner or later, almost all of us find someone to mate with, no matter how repulsive and socially inept (and under-endowed) we may be. By comparison, among gorillas and baboons for example, almost all the babies are the offspring of the one big dominant male. This is more or less true of all species that go in for large impressive males. In any species where you see vivid plumage and fins, big teeth and antlers, exotic singing and dancing and scrapping, observed from the sidelines by relatively quiet dowdy females, you can expect that the vast majority of males will never (and I do mean never) get the chance to mate (unless they're very sneaky) and all their genes will be completely lost to the gene pool. By contrast, almost all the females will get to mate.
Humans are different. For all our bragging and posturing and the very obvious sexual conquests of our alpha males, the fact is that the vast majority of us also find our beta, gamma and omega mates in due course and, on average, produce just as many sproggs in the long run, if not more.

At any rate, one thing is for certain - we can't rely on biology to make us better people. That we will have to do for ourselves.