Okay. Let's say that there is a sudden shift in climate etc. Your species adapts to it genetically. Soon after this adaptation, however, another change in the opposite direction occurs. Your species is even further from its previous baseline now, so adapting again in such a short time would be far more unlikely, which is believed to be the reason why many species go extinct.

ah well this is true but it isn't really about evolution

Evolution is genetic adaptation over generations.

Well. Mutation as well, so even if it isn't an 'adaptation' I suppose.

I.e. serves no real purpose

well the thing is that the change is gradual

so a siginificiant shift in the "wrong direction" cannot really occur

the "defective" individuals will become unable to reproduce way before thst

Sure it can. Sudden events can lead to rapid change.

what you said only matters when the population is really small

like, really small, when every speciman matters

no, mutations don't become more drastic

Not all mutations are equal. And beyond that, the frequency at which they occur can definitely change.

Environmental stressors can play a part, for instance. Of course with epigenetics now being studied. We might find new data I think. I'm not sure how that impacts mutation. But it seems like mutation to me at some level.

Huh. Well I doubt that's a significiant factor.

Again it really depends upon the scenario. I'm not talking about most of the time.

well back to gays, even if we argue that altruism is not always good, doesn't the persisabtce of homosexual genes prove that they werr somehow beneficial for the species?

no

it implies that it's good for people with that gene

stop thinking of genes as benefiting the species

No. We have plenty of genes that serve no purpose or are actively detrimental.

yeah but aren't they usually significiantly more rare

@Tero how can it benefit the homosexuals themselves

i already said how

Genetic diseases are common. They don't really benefit anyone.

Now

but each particular genetic disease usually isn't

If homosexuality is activated by the same genes that activate something else, like making someone's reflexes extremely high, then it might be a byproduct of something beneficial

But I don't see a case beyond that

@unfriendly teapot

Plus the homosexual trait itself isn't beneficial, just a byproduct, in that situation.

Also, why are we accepting that it is in fact genetic in the first place?

well it's somewhat heritable

If it were genetic, it would have a tendency not to be expressed after several generations, I'd think.

I've not heard of this

yeah identical twin of a homo has a 25-50% chance of also being a homo

Plus, homosexuality is purely behavioral. It can be explained by upbringing. If you 'inherit' it from a parent, it might have simply been learned.

I'm not saying it isn't genetic, but I don't think we can really determine one way or another. At least right now.

I'm also going to assume that none of the twins studied had been separated for control.

imo genetic + epigenetic effects are probably the largest contributors

the thing is you can go down the list of relatedness, from identical to fraternal twins, to mere siblings, to cousins, etc. and find the decreasing correlation