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.

10 comments:

Vincent said...

I think you must be right on this. I'm writing not to dispute anything but to mention a book I'm reading called Sex, Time and Power: how women's sexuality shaped human evolution by Leonard Shlain. He examines the extraordinary differences between us and the other primates and particular how we could have evolved in a way that seemed at first to have put us at a disadvantage in a great many areas, of which difficult births consequent upon walking on two legs is only one. He endlessly talks about menstruation and women's need for iron, and of course sex.

The most relevant issue in terms of your topic is his idea (not his original idea but a key one) that the evolution of hominids arose from some environmental necessity. The "African Eve" had certain unlikely traits which helped her be the mother a new species which could cope with new conditions impossible for her predecessors to survive. (Evolution, you might say, is conservative. When a winning formula continues to prevail, mutations will be less likely to gain ground.)

In another part of the book he refers to homo sapiens as a parasite, because there are so many nutrients essential to our survival that we cannot create within ourselves, so are reliant on "hosts" to get them for us.

He defines successful parasites as those which suck these nutrients from their hosts/victims without weakening them so much as to kills them. The tapeworm is successful because it makes sure not to kill its host.

A "stupid" parasite is so greedy that it kills its host and so dies itself. Stupid parasites are reclassified as pathogens. In relation to our host, Earth, he says "we have transmogrified into the planet's most virulent pathogen".

If we strangle our host we will either go extinct ourselves or go through a rapid evolution like that "African Eve" so that we can survive without dependence on all the organisms we have rendered extinct.

Bryan M. White said...

Given your explanation, I take your remark to be similar to the ideas at the beginning of the movie Idiocracy (which you should see the first five minutes of, at least, if only because what you've said here is so reminiscent of that. The rest of the movie is fairly mediocre.) However, I can see how the remark would drop like a lead weight in the middle of a party. (Never talking to you again seems a little harsh though. People shouldn't lose friends over these sorts of things.)

Bryan M. White said...

Yeah, here's a link, if you're interested:

http://www.youtube.com/watch?v=BXRjmyJFzrU

Vincent said...

Excellent clip in terms of making its point humorously. Whereas my own comment was fairly off-topic, whilst managing to avoid being rude. An improvement for me.

John Myste said...

This is a very good observation, as shown by the fact that Sniper Vincent found no way to detract from it.

No offense to Sniper Vincent.

Steve Law said...

'Sniper Vincent' I like that. As for the not being rude this time Vincemnt - i'm sure there will be other opportunities. I thought you might enjoy the politically incorrect bit.
I saw the Idiocracy posters when it came out and thought it was a very amusing title but I didn't know what it was about. Sadly, can't watch the clip having no sound card on my PC. I'll try to remember next time I'm on my wife's Mac.
More to the point - I had a quick look at the Shlain book's reviews. There was a lot of this evolutionary speculation (usually by non biologists) a while back. I've not been keeping up with the latest manifestations. Arguably Ethology, Sociobiology and Evolutionary Psychology may be more academically respectable but more of the same. In general they tend to be short on evidence and testability but are thought provoking nonetheless. My favourite is the Aquatic Ape theory mostly promulgated by Elaine Showalter (a journalist) back in the Seventies. She also focussed on how the female shaped our evolution, trying to get away from Desmond 'Naked Ape' Morris's preoccupation with the male's hunting prowess. Whatever the merits of that, I still don't think anyone's adequately explained why Homo sapiens, alone among African savannah mammals, opted for body fat instead of hair - a feature normally exclusive to aquatic and semi-aquatic species. Most modern biologists (often rather reluctantly) have to ignore the Aquatic Ape theory because there's just no evidence but it's fun to speculate. Shlain's book looks a bit more hippy-woolly to me but I've not read it.

"The "African Eve" had certain unlikely traits which helped her be the mother a new species which could cope with new conditions impossible for her predecessors to survive."
This is pretty much a description of speciation generally, but the traits that distinguish us from our closest relatives and pretty much all other mammals are certainly pretty unusual, which is why trying to extrapolate our 'basic nature' from other species (baboons, chimps) as Sociobiology etc attempt to do is a pointless and usually circular undertaking - Humans are aggressive and hierarchical, like baboons, therefore, since baboons don't have culture (?), aggression and hierarchy must be innate. And then someone brings up bonobos and it all goes to pieces, but we are so very different to both baboons and bonobos that any extrapolation is just a matter of picking and choosing depending on your pet theory about what humans are basically like.

Yes Bryan - my social ostracism. Well to be fair it wasn't the only thing. I was unusually socially inept back then. I hope I've improved. But the student teachers were the worst - a terrible humourless and judgemental lot.

Vincent said...

No offence taken, John. I want to give up sniping, it's a filthy habit though pleasurable in a nasty way. As for the clip's political incorrectness, I didn't even notice that.

I've decided to stay out of anything which I don't understand: political correctness, gay marriage & other apparent oxymorons that never existed in my formative years.

And reading further, I've gone off Leonard Shlain too.

Steve, at any rate you and I have this in common, that we can retreat into humorous self-deprecation. No offence, or indeed offense, intended to John & Bryan, who I think are not unfamiliar with the same useful commodity.

Vincent said...

Yes, Shlain does refer to the aquatic ape theory. He rather likes it as an explanation for bipedal locomotion, lack of body hair etc, but it doesn't deflect him from his main theme of women and sex. They're constantly losing iron (from periods, childbirth etc) and so they will sell themselves at any time to a hominid who tries to seduce them with the gift of red meat, even when they are not ovulating.

So Shlain is not really interested in the basic nature of humans, so much as trying to understand how nature protected them in the thousands of years before they became dominant.

It's interesting to get his medical diagnosis of the male teenage years (Shlain was a surgeon by profession, "was" because he died in 2009). To have lots of testosterone and not enough sense was a way to encourage this young hominid at his most sexually potent to be crazy enough to take enormous risks in his hunting to get the red meat and buy some sex.

The TV series Jackass bears tribute to this evolutionary heritage.

Steve Law said...

I meant 'basic' in the sense of nature rather than nurture - before culture, upbringing, education, society and so on have their nefarious ways with us.

"[women are] constantly losing iron... and so they will sell themselves at any time to a hominid who tries to seduce them with the gift of red meat" is one of those speculations which sounds plausible to the layman but where there's just no way of proving it wrong. They appeal to some people's common-sense preconceptions about human nature rather than having any particular claim to truth.
There's lots of other just-so stories like this in 'the literature', particularly about sex. The examples cited - Why Teenage Boys Drive Like Idiots, and Why Women Are More Likely To Shag You If You Buy Them Dinner are typical. Elaine Morgan's are particularly lurid actually. She speculated that when people began to walk upright the vagina became inaccessible to the normal mammalian mating position (from behind) and the male therefore had to throw her on her back and force her to put up with it. Apart form the obvious silliness, I can only assume that Ms Morgan had had only very unadventurous partners.
(That should have been Morgan incidentally, not Showalter mentioned in my earlier comment.)
Most working evolutionary biologists would steer well clear of these sorts of 'explanations' unless there was some very good evidence available.

Btw, my missus, who is a midwife, would challenge the idea that human childbirth is naturally traumatic. The traditional birth position (on the back, legs in the air) has a lot to answer for. Also, more controversially perhaps, she tells me that teenage mums more often give birth practically 'on the hoof', like other mammals, which may tell us something about what is 'natural' for human beings, even if highly questionable ethically.

Bryan M. White said...

Your double negative threw me for a loop there Vincent. I had to blink twice and read it again. Good stuff :)

...and Steve, teenage mothers giving birth "on the hoof"...I don't think I needed that image in my head this morning. :)

Carry on guys.