For sexually reproducing species, evolution will disfavour genes that lead to individuals slaughtering others of their species for little or no reason. Slaughtering members of the opposite sex obviously reduces mating opportunities. Slaughtering members of the same sex reduces the mating opportunities of their opposite-sex children.
This obviously hasn’t completely prevented humans from slaughtering both particular individuals and entire populations of humans of a different tribe. But this isn’t what always happens. It could be a lot worse.
Maybe it is worse for asexual species (mitigated by slower evolution without sex), perhaps explaining why at least for vertebrates asexuality is rare, and asexual species seem to not last long.
For sexually reproducing species, evolution will disfavour genes that lead to individuals slaughtering others of their species for little or no reason. Slaughtering members of the opposite sex obviously reduces mating opportunities. Slaughtering members of the same sex reduces the mating opportunities of their opposite-sex children.
This obviously hasn’t completely prevented humans from slaughtering both particular individuals and entire populations of humans of a different tribe. But this isn’t what always happens. It could be a lot worse.
Maybe it is worse for asexual species (mitigated by slower evolution without sex), perhaps explaining why at least for vertebrates asexuality is rare, and asexual species seem to not last long.