(Continued)
OK. We've moved on from the hunter-gathering, the gays are still with us, and humans have discovered agriculture and have become settlers.
The natural order seems to be that things belong to families (rather than to individuals or groups), so children don't inherit stuff so much as the older ones just drop out of the picture. But there's a limit on what you can inherit (obviously) and there is also a limit on the amount of new land that you can adapt for agriculture (it takes ages to get the trees to grow, to dig the ditches, to get the soil fertilised etc), which in turns set an upper limit for how quickly the population can increase.
To ensure the survival of the human race, every heterosexual couple has to have at least two children, so there is an evolutionary advantage to having more (if you have less, you will die out). But the more children any particular human couple has, the more likely those children and grandchildren are going to waste time, energy and indeed lives fighting between themselves over who gets what.
So Nature slams on the brakes; it has a mechanism whereby, the more baby boys a woman has had, the more likely it is that the next baby boy will be gay - hooray! The number of descendants, but the survival chances of her grandchildren are even more secure (as I explained in Part 3).
More anon.
A small change of theme
1 hour ago
9 comments:
Hang on.
In the last post you were saying that the gay gene was passed on from a gay aunt or uncle "diagonally" (how remains a mystery) - now we've skipped on to it being passed down from parents to children (viz the paper I directed you to). Your thinking on this is all over the shop!
Nature v Nurture? How about it being both - probably about 50-50 as well. As Ken Livingstone put it - 'we are all bisexual' - to varying degrees obviously.
Although the youngest boys are more likely to be gay, there are still some eldest boys who are gay who have heterosexual younger brothers. This suggests there is a genetic element as well as being nurtured.
My head hurts...
Daniel, this is a crash course in the various reasons why a small number of gays is part and parcel of evolution. Of course there's more than one reason.
Neil, nurture? How come there are just so many gays in totally homophobic societies where it's punishable by death? That's hardly encouragement is it? Apart from extreme case of prisons, I (personally) doubt that nurture has much to do with it.
This is pure speculation (and tries to answer Daniel's point) but here goes...
Simon Baron-Cohen has been carrying out a whole load of research into autism and has a whole bunch of research into what he calls EQSQ (I think it's Empathising Quotient/Systematising Quotient).
Systematising is a "male" thing. So someone designing microchips is more inclined that way. Empathising more of a "female" thing, so someone like a counsellor or nurse is more inclined that way.
Baron-Cohen has shown that children who score highly in systematising test also had high levels of testosterone in the womb, which suggests that there's a lot of "nature" going on.
Generally men are stronger in SQ, women in EQ but there are big variations. One of the things that's been noticed is that autistic boys generally have parents who are both strongly SQ, that autistic people end up extremely SQ.
Now, Baron-Cohen doesn't say this, but I believe there could also be a link with sexuality. The jobs that we might consider "EQ", where empathy is important are also those jobs where men working in them are often known to be homosexuals (also, you'll rarely if ever meet a gay male engineer, but you will meet lesbian ones).
So, if we say that EQSQ levels may be genetic, then maybe sexuality could be. That if you're born to say, two actors, that maybe you've got a lot more chance of being gay than being born to an actor and a mathematician.
It may be that both extremes get filtered out. That too many scientists mating results in children who lack the social skills to get a mate. And at the other end of the scale, you get gay men who can't breed.
Mark, remember that as far as natural selection goes, it doesn't matter how many kids one has, it matters how many kids one has relative to everyone else. It is the differential fitness of organisms, not the absolute fitness that counts. So you can still have evolution in a dwindling population.
Daniel, I think Mark's point was that though your genes are inherited from your mother and father, some will be shared with your uncles who may express them, i.e. be gay, where your parents are not. So your uncle, through providing care, the conventional vertical transmission of characters.
Mark, have you considered that homosexuality may be partially memetic? That it is a replicating idea that governs behaviour rather than their genes. This would explain the pride parades, the established culture and mannerisms, etc.
So your uncle, through providing care, the conventional vertical transmission of characters.
=
So your uncle, through providing care, may assist the conventional vertical transmission of characters.
Anon "It may be that both extremes get filtered out. That too many scientists mating results in children who lack the social skills to get a mate. And at the other end of the scale, you get gay men who can't breed."
Substitute "don't breed" for "can't breed" and that's another very good point.
PT, combine the basic theory that kids with gay aunts and uncles have better survival chances, but that they also have 'alternative' rôle models, and that's a whole new (and rather good) explanation, but it doesn't explain existence of gays and lesbians in homophobic societies (i.e. most outside the Protestant democratic Western world and poss. some S.E. Asian ones).
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