@jeffcliff @Ricotta @miria @tsukiko That would require an immense reproductive benefit to one's kin to offset the direct reproductive cost. There is no evidence for any such effect, let alone one large enough to work.
@ArdanianRight @tsukiko @miria @jeffcliff @Ricotta
> There is no evidence for any such effect, let alone one large enough to work.
Actually there is. Cooperative behavior that had a negative expected value from the individual perspective (versus not being cooperative in that instance) but a positive expected value overall for the group at large has been empirically demonstrated. One of the documented examples was in fish, I don't have the paper on hand though.
It's important to remember that you share a significant fraction of your genes with siblings and other family members. So a probabilistic approach is sufficient for the purposes of natural selection.
For example, genetics which resulted in, say, 25% of the population not reproducing but that were somehow of net benefit to the species overall could be selected for if the distribution was uniformly random. Obviously if it takes out an entire batch of siblings together that won't work but if it takes out 1 in 4 of a given family that could.
> There is no evidence for any such effect, let alone one large enough to work.
Actually there is. Cooperative behavior that had a negative expected value from the individual perspective (versus not being cooperative in that instance) but a positive expected value overall for the group at large has been empirically demonstrated. One of the documented examples was in fish, I don't have the paper on hand though.
It's important to remember that you share a significant fraction of your genes with siblings and other family members. So a probabilistic approach is sufficient for the purposes of natural selection.
For example, genetics which resulted in, say, 25% of the population not reproducing but that were somehow of net benefit to the species overall could be selected for if the distribution was uniformly random. Obviously if it takes out an entire batch of siblings together that won't work but if it takes out 1 in 4 of a given family that could.
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@roboneko @tsukiko@freak.university @ArdanianRight @miria @jeffcliff @Ricotta Gay uncle theory is a meme. The fact the birth order effect persists even across stillbirths proves that. The memed reproduction benefit with no mechanism is in the opposite direction
It's a deteriorative mental illness that's more likely to pop up the more fertile a woman is
https://slate.com/technology/2008/06/a-genetic-theory-of-homosexuality.html
> uncle theory is a meme
You're the one bringing a specific theory up, not me. I was simply laying out how genetic traits that are detrimental to a given individual can still be selected for under certain circumstances.
However, since you brought it up. What do you mean by "the birth order effect persists even across stillbirths"? I've never heard of "uncle theory" or "birth order effect" but if you're saying that there's some correlation that doesn't go away when stillbirths happen that is actually perfectly compatible with the sort of statistics I was describing. As long as stillbirths aren't common enough to influence the overall numbers on a population scale then they're likely irrelevant to the process.
> It's a deteriorative mental illness that's more likely to pop up the more fertile a woman is
The article you linked summarized an academic paper that makes a case for the second thing you said (ie correlated with fertility). Not sure where you're getting the "deteriorative mental illness" thing from.
@tsukiko @ArdanianRight @miria @jeffcliff @Ricotta