This came up in another discussion thread, but I really thought it deserved a separate thread all it's own.
Why would Gays exist in a Darwinian universe?
Obviously, you can't say it was through some form of genetic mutation and adaptation. Gays are, in their own terminology, not 'breeders.'
If Gayness...I prefer the term 'Gayiety'...exists, as it undeniably does, then what evolutionary need do these 'non-breeders' add to the human genome?
There is no obvious mechanism for gays as a product of natural selection (probably the attempts to do so: 'providing additional support for the group' etc seem to be pretty much a case of reaching--and are a form of appealing to group selection, which has been pretty much discredited as a significant evolutionary mechanism).
However many attributes develop not as direct selection, but as by products of something else, I suspect in this case by products of our highly tuned 'always on' sexuality (which is different from most mammals). This mechanism is highly effective, but also through natural variation produces some members that wind up not directly contributing to reproduction.
It should be noted that while it IS true that we occasionally see same sex behavior in animals, it tends to be far more rare (if it weren't anyone who works in any kind of animal husbandry would have seen it countless times) and is often not permanent (i.e. animals may do it for a time but not always). Human sexuality has a far stronger bonding component than most animals (with good evolutionary reason) so it is not surprising to find that our behavior in this area is a bit different as well.
I would rather stay away fron the 'it's found in nature argument' to defend gay rights, certainly our definition of rights should not be based on what non-human animals do or don't do.
Are there chromosomal or genetic syndromes that result in nonbreeding individuals? Why do they persist?
there are some... here, also:
cystic fibrosis, sickle-cell disease, Tay-Sachs disease, Niemann-Pick disease, spinal muscular atrophy, and Roberts syndrome.
LGBT people DO breed. A lot of them have genetic children. Historically, probably more did, until 20th century social fluidity and ostracism resulted in reduced fecundity. So it's not as dead end as people think.
There are also eusocial species - mainly insects - in which the vast majority of colony members are sterile. Honey bees, thousands of sterile workers to one queen and a handful of drones. Quite a number of other species as well.
The eusocial insects are often cited by those trying to support the group fitness model of natural selection. Most evolutionary biologists don't buy group fitness as a significant mechanism because it simply does not stand up to mathematical analysis.
The huge difference between eusocial insects and other animals is that the whole hive is one single genome. For natural selection purposes, individual ants are merely parts of a single organism, no individual is at all important. It makes no difference which particular ant reproduces.
'Group selection' in other animals is quite different because the non-reproducing individuals are NOT part of the same genome even though they may be related. They benefit very little by being non reproductive.
Sentient, why do you start with a list of diseases? Is there any indication of correlation between diseases of parents and non breeding individuals?
Now I am really confused. Several of my family and friends who are homosexual, male and female have chosen to have children, either by adoptions, or a surrogate mother, or artificial insemination. As to parenting, the ones I know make outstanding parents and the kids are well adjusted if the parents accept themselves as they are.
I also know non-breeding pairs who don't want children and they make wonderful family members and neighbors.
So, why, "Why are there Gays in a Darwinian Universe?" seems irrelevant to a flourishing individual or couple. Isn't that question tied to the religious belief that the purpose of life is reproduction? Maybe Gays in a Darwinian Universe are what we need on a planet that is getting worn out from all the human made pollution.
Not all cultures perceive homosexuality as bad thing. I ran across this rather interesting, and new to me, concept.
There is a Greek Model, The Melanesian Model, The Western Model,
These three coincident homosexual streams, each very different from the other, in a context in which humankind shares more than 99% of its genes, means homosexuality does not conform to any genetically prescribed model. In a genetic model, homosexual behaviours would be practically identical. Not only are there quite different models—the Greek, Melanesian, and Western—co-existing today, but there are a myriad of other homosexual customs and practices, not the behavioural uniformity associated with a genetically dictated homosexuality.
There is a Greek Model
Not one to follow, basically child molestation.
I think Sentient's point is that things that are disadvantageous to individuals may still be advantageous on a species level. And this is a valid point. While certainly gay people CAN choose to reproduce, and many do, it takes a conscious action outside one's inclinations to do so.
But in this discussion (and the quoted article), some of the things that are included in homosexuality are intentionally not included in the modern definition context. A person who engages in a sex act as part of ritual, or as an opportunistic action, is not considered homosexual in the modern sense any more than a person who engages in heterosexuality because of social pressure or to become pregnant is actually straight.
Hm-mm, how do I state the question in a way that discourages a knee-jerk denial?
I guess it's not possible. I'll ask anyway.
Are you assuming that adult behavior is, or should be, motivated by a desire to reproduce?
This is typical of academic research, where leftover Victorian values don't allow orgasm as a motivation.
The question is different depending on what level you ask. Natural selection rewards sexual reproduction, and 'nature' does not give a whit what motivation we humans (or other animals) have for the act.
On the individual level, sex, like food, induces us to follow nature's 'directives'. I am sure that when dogs mate, building the next generation is NOT what's on their minds.
Jay, I agree; Ma and Pa Nature don't care. Nor do any gods.
I provided for and trained a couple of German Shepherds but didn't think to ask them.
The several cats who let me feed them didn't give me the time of day.
If a culture is motivated by religious values, at least in Abrahamic faiths, the purpose of copulation is reproduction. Susan, correct me on this if I am wrong about this for Jewish couples.
For a modern, enlightened couple, the purpose of copulation is pleasure, whether hero- or homo- sexual.
Wrong question! Why is there not acceptance of those who don't fit the perfect person profile? We have come a long way with accepting cerebral palsy and Down's Syndrome. We have a lot more maturing to do before we get out of the Dark Ages.
They offer diversity! Not all genitalia and hormones develop the same way.
We want ticky-tacky people living in ticky-tacky houses doing ticky-tacky work with a tricky- tacky education. Don't let anything be different than ticky-tacky.
Ticky Tacky Houses, Levittown, PA
From what studying I have done on the matter it could be that homosexual males benefited the clan/tribe by helping seeing their nieces and nephews survive to adulthood to be able to mate with other members and, in so doing the gay brother or cousin or son contributes to the survival of the family genes. Not only that but they most likely had a hand in teaching the children to hunt and how to survive, and kept them in line when they got unruly.