Homosexuality and the natural order

[Francesca R]

Copied from another thread where it was borderline off-topic and got lost:

http://www.economist.com/science/displaystory.cfm?story_id=8074843

Homosexuality has been recorded in some 1,500 species so far, and been well documented in about a third of these cases; it has been known since the time of Aristotle, who thought he witnessed two male hyenas having sex with one another. But the exhibition's purpose is not to educate zoologists. It is to persuade the public that, as there are gay whales and worms, gay humans do not disturb the natural order.

Why this behaviour might be favoured by natural selection, though, is a difficult question to answer . . .

Theoretically, there are several possible ways homosexuality could have evolved . . .

. . . But testing these theories is hard, so nobody knows if they are true.

A germinating challenge to the view that homosexually is an abberation of no benefit to a species. Unfortunately not well developed in this article, though interesting.

Any thoughts?

 

[Dancing David]

I agree with the premise of the cited material, but I believe that female hyenas have penises.

Chimps are immoral and have turned thier backs on god, so god made them smaller and hairy.

 

[hammegk]

No doubt about it; if worms, whales, and monkeys do it, so should humans.

 

[alock]

Performing a homosexual act is completely different to forming a homosexual relationship or exclusively wanting to perform homosexual acts.

I don't know the specifics of the research, but there are many reasons why members of the dominant sex might practice these acts. Young pack animals play fight with each other. This is normal behavior and helps prepare them for later life.

 

[Marquis de Carabas]

A germinating challenge to the view that homosexually is an abberation of no benefit to a species. Unfortunately not well developed in this article, though interesting.

Any thoughts?

Scientifically, it's interesting to investigate from whence homosexuality came. Ethically--and, this being in R&P, rather than SMMT, I can only presume ethics are at least a partial concern--it doesn't matter how homosexuality developed.

ETA: Oh sure, now it's in SMMT. I hate you, mods.

 

[Beady]

Sagan and Druyan went into this to some extent in Shadows of Forgotten Ancestors, citing studies done in zoos. It's been ~five years since I read it, but I recall that there's always some small level of homosexual activity in ape populations, and the activity increases throughout the group almost in direct proportion to population density. The authors don't come right out and say so, but it's difficult to avoid the conclusion that they want to argue it's a sort of natural pressure valve.

If that is the case, then there's evidence that homosexuality has survival value for a species.

 

[steenkh]

A germinating challenge to the view that homosexually is an abberation of no benefit to a species.

It is more to the point to say that homosexuality is a behaviour that been proved not to be damaging to a species.

 

[matt-r]

Sagan and Druyan went into this to some extent in Shadows of Forgotten Ancestors, citing studies done in zoos. It's been ~five years since I read it, but I recall that there's always some small level of homosexual activity in ape populations, and the activity increases throughout the group almost in direct proportion to population density. The authors don't come right out and say so, but it's difficult to avoid the conclusion that they want to argue it's a sort of natural pressure valve.

If that is the case, then there's evidence that homosexuality has survival value for a species.

You always run into the problem though that evolution doesn't really apply to species, but to individuals (or individual genes). Whether or not it's better for the species as a whole for an individual to have a "crikey there are a lot of people about, I'd best go gay" gene, it's almost certainly not advantageous to the reproductive success of that individual. It's still possible that there's an evolutionary mechanism whereby an individual with the "crikey" gene is better able to devote time to the care of siblings/other relations with whom he/she does share genes, thereby giving an advantage to those genes in the bodies of others.

Oh, and let's be careful about the whole moral fallacy of "evolution dunnit therefore it is morally good" - that's a two-way street, and most people don't like the oncoming traffic! The "natural order" arguments can be knocked down without having to show that homosexuality is a product of evolution.

Matt

 

[Roboramma]

You always run into the problem though that evolution doesn't really apply to species, but to individuals (or individual genes). Whether or not it's better for the species as a whole for an individual to have a "crikey there are a lot of people about, I'd best go gay" gene, it's almost certainly not advantageous to the reproductive success of that individual. It's still possible that there's an evolutionary mechanism whereby an individual with the "crikey" gene is better able to devote time to the care of siblings/other relations with whom he/she does share genes, thereby giving an advantage to those genes in the bodies of others.

You don't even need to go into kin selection to explain that. The fellow who's "going gay" may already have children. He's got to devote enough resources to raising them, and resources are scarce enough already what with this high population density, that having more mouths to feed is likely to end him up with fewer rather than more successful offspring.*
(successful in this case meaning "surviving to reproduce").

Something similar happens with birds who come together, judge their relative population density, and then lay fewer eggs the higher the population density is currently. Not for the good of the species, but because it's better to have two chicks that survive than five that don't.

*All speculation, of course, and I doubt the above would stand up to testing as a valid hypothesis. But something like it might. I just wanted to point out that while kin selection is awesome, it's not the only way that homosexuality could evolve.

 

[matt-r]

You don't even need to go into kin selection to explain that. The fellow who's "going gay" may already have children. He's got to devote enough resources to raising them, and resources are scarce enough already what with this high population density, that having more mouths to feed is likely to end him up with fewer rather than more successful offspring.
(successful in this case meaning "surviving to reproduce").

Something similar happens with birds who come together, judge their relative population density, and then lay fewer eggs the higher the population density is currently. Not for the good of the species, but because it's better to have two chicks that survive than five that don't.

Good point. My argument was biased by my own experience, which is that (if there is a "crikey" gene) it kicks in way before you do/are likely to have kids. Some obviously go on to produce kids nonetheless due to societal pressure. Anecdotally my understanding is that my own experience is pretty common. (Pre-)historically though, who knows what the typical experience of your average gay early human was?

I've realised a further problem with the crikey gene though - why would it turn you gay rather than cause you to simply lose interest in sex, or stop producing sperm/eggs? Surely time spent chasing the same sex is less time spent devoted to the upbringing of your kids?

Matt

 

[Dancing David]

No doubt about it; if worms, whales, and monkeys do it, so should humans.

Especialy eating thier young!

 

[Dancing David]

Performing a homosexual act is completely different to forming a homosexual relationship or exclusively wanting to perform homosexual acts.

I don't know the specifics of the research, but there are many reasons why members of the dominant sex might practice these acts. Young pack animals play fight with each other. This is normal behavior and helps prepare them for later life.

That would be "down low" arguement, there were thyese great guys on Oprah who stated that they preferred homosexual sex, actively seek out homo sex, but they say they are 'straight'.

I feel that humans fall on a bisexual spectrum, some tend towards one end or the other.

 

[ponderingturtle]

Performing a homosexual act is completely different to forming a homosexual relationship or exclusively wanting to perform homosexual acts.

Then you are going to have to limit your research to species that actualy form long term sexual relationships. And you know what, there are plenty of homosexual ones here too.

 

[Dancing David]

Good point. My argument was biased by my own experience, which is that (if there is a "crikey" gene) it kicks in way before you do/are likely to have kids. Some obviously go on to produce kids nonetheless due to societal pressure. Anecdotally my understanding is that my own experience is pretty common. (Pre-)historically though, who knows what the typical experience of your average gay early human was?

I've realised a further problem with the crikey gene though - why would it turn you gay rather than cause you to simply lose interest in sex, or stop producing sperm/eggs? Surely time spent chasing the same sex is less time spent devoted to the upbringing of your kids?

Matt

I think that the issue might be that humans are evolved to be sexualy active, humans have free cycling esterous, and therefore have a loose non-seasonal sexuality.

So maybe humans are just evolved top be seuxaly active.

 

[Beady]

You always run into the problem though that evolution doesn't really apply to species...

I'm not talking evolution, I'm talking survival of the species. I never said that homosexuality has evolutionary value; it's entirely possible to argue that the two things are, or can be, mutually exclusive.

Getting back to it, there are several mechanisms by which population density can be controlled. Of them all, I think I would prefer homosexuality; at the very least, it has a much higher comfort index than starvation.

 

[John Hewitt]

Sagan and Druyan went into this to some extent in Shadows of Forgotten Ancestors, citing studies done in zoos. It's been ~five years since I read it, but I recall that there's always some small level of homosexual activity in ape populations, and the activity increases throughout the group almost in direct proportion to population density. The authors don't come right out and say so, but it's difficult to avoid the conclusion that they want to argue it's a sort of natural pressure valve.

If that is the case, then there's evidence that homosexuality has survival value for a species.

There are many discussions about the origin of homosexuality and it is certainly well known in the animal kingdom. However, so far as I know, only in humans is there a minority of the population that is entirely homosexual. Homosexual acts in other species seem to reflect a bisexuality rather than homosexuality. I would also suggest that the problem of the evolution of homosexuality might usefully be seen as part of a more general problem, namely the evolution of sexual deviation.

It would be sensible, for example to ask about the evolution of sadism, masochism and fetishism, all of which seem to be comparable in incidence with homosexuality.

So far as I know, my own work is the only study that produces an integrated theory with such properties.

 

[ponderingturtle]

There are many discussions about the origin of homosexuality and it is certainly well known in the animal kingdom. However, so far as I know, only in humans is there a minority of the population that is entirely homosexual. Homosexual acts in other species seem to reflect a bisexuality rather than homosexuality. I would also suggest that the problem of the evolution of homosexuality might usefully be seen as part of a more general problem, namely the evolution of sexual deviation.

I don't think that fits. Do you have evidence that the homosexual birds who have long term commitments cheat on their partner with the oposite sex?

Basicly I would like to see your evidence that there are not homosexual exlusive animals and that they are much more pridominantly bisexual.

 

[Beady]

However, so far as I know, only in humans is there a minority of the population that is entirely homosexual.

I'm not convinced that there's such a thing as being "entirely" homosexual. That concept has yet to be established as fact. For that matter, I'm beginning to doubt that anyone is "entirely" heterosexual. To me, the whole idea of sexual preference is beginning to look like a matter of degree, rather than either-or.

 

[headscratcher4]

http://www.glumbert.com/media/fifties

Watch and learn.

 

[Roboramma]

I'd also ask whether being "entirely" homosexual was something that occured at all amoung our hunter-gatherer ancestors. I doubt it.
Arranged marriage would have been very common. And I'm not entirely sure that even men could get on well without female partners (from whom they would get a large part of their vegetable food, but then mothers and sisters might help...)

Anyway, I don't know, I haven't seen the evidence for the incidence of homosexuals who don't partake in hetrosexual sex among hunter-gatherers. If they don't exist, then suggesting that we're different from other animals because of their existence in modern society is like saying we're different from other animals because we have sports stadiums and cheerleaders.