You need to spend some more time with evolutionary theory. Populations do indeed evolve along with individuals. You own message explains why; there are selection pressures at the population level as well. See also animals that are always found in communities, like ants or humans. It's not either/or. It never is with evolutionary theory.
"Populations do indeed evolve along with individuals"
Individuals don't evolve at all. Evolution is changes in gene frequency over time.
What I think you're trying to talk about is macroevolution, where species that happen to have certain traits survive longer than other species. Sure, this sort of thing happens. But I was responding to the claim that "absolute cowardice [is] beneficial to an individual" and noting what would happen to the level of cowardice in a population if that were actually true.
What it looks like you're not paying sufficient attention to is that selection happens at the level of the gene, not the level of the individual.
It is absolutely not beneficial to the individual to put energy out to try to have sex, put energy into offspring, or to take risks for others. However all of those behaviors have tended to be beneficial for the genes that the individual has because the others who are helped are likely to have the genes producing that behavior. Therefore all of those behaviors have evolved notwithstanding the fact that they are inconvenient for individuals with those genes.
The truth is that the truth you allude to is only one of many truths, and I consider it my duty as a mansplainer to point out that there are other truths you failed to incorporate into your paragraph in such a way that makes me feel as if I have a bigger and more complete collection of truths because then I won't feel so bad that my pants make me feel ugly.
What you refer to as macroevolutionary effects are equally problematic for a small village. It will quickly be destroyed and any wealth it has taken by a neighboring village whose warriors are not afraid to give their lives in service of their chief.
Last I heard there was still some ongoing debate among ev biologists about whether group selection was an important effect or not; I think the general consensus tends to be that it's a pretty small effect except in certain special cases.
The existence of traits like courage is far better explained by sexual selection. Women throughout history have always strongly preferred courageous men to cowardly ones. This is only partially cancelled out by the fact that courageous men tend to die more often.
As civilization continues to advance, and fewer and fewer people die before childbearing age, I'd expect the balance between sexual selection and survival selection to tip even more strongly in favour of sexual selection, so it's quite likely that (even absent widespread genetic modification) the people of the future will indeed tend to be "sexier" than the people of the present.
(Partially cancelling this out is the idiocracy effect whereby poor dumb folks have more children; I can't estimate which is more powerful.)
>The existence of traits like courage is far better explained by sexual selection. Women throughout history have always strongly preferred courageous men to cowardly ones.
That's not an explanation. Why do women prefer courageous men?
Do you mean to imply that courage is like a Peacock's tail? It doesn't help a man survive, but it signals that he must be really good at surviving in other ways.
