Kin selection: organism X helps organism Y because it improves the prospects for the part of X's DNA that Y also has. The more related X is to something, the more willing X is to sacrifice itself for it. The most extreme example is also the most familiar: each of your cells has DNA identical to each of your other cells (if all is well). So a cell is completely willing to kill itself for the "collective", even at the expense of its own ability to reproduce. A less extreme example is that of a woman declining to pursue kids of her own in order to help tend her sister's, which could be adaptive when, e.g., food is scarce.
Group selection: members of a particular group (e.g., a tribe) are willing to engage in altruistic actions (e.g., suicidal defense of said tribe pre-procreation) even though doing so maladaptive at the level of the individual's DNA. This kind of cooperation is adaptive for the group as a whole, but not in the least for the individual. Groups that encourage this kind of behavior will outcompete groups that don't, so groups are selected for this trait.
IIRC, the primary reason that group selection is thought to be wrong is that it (apparently) can't yield an Evolutionarily Stable Strategy (ESS) -- it will always be better for the persistence of any individual's DNA if that individual refuses to be altruistic.
>IIRC, the primary reason that group selection is thought to be wrong is that it (apparently) can't yield an Evolutionarily Stable Strategy (ESS) -- it will always be better for the persistence of any individual's DNA if that individual refuses to be altruistic.
I don't think that could be right, because the altruistic individuals altruism could include killing/punishing non-altruistic individuals. Shooting deserters comes to mind, as a real-life human example.
"IIRC, the primary reason that group selection is thought to be wrong is that it (apparently) can't yield an Evolutionarily Stable Strategy (ESS) -- it will always be better for the persistence of any individual's DNA if that individual refuses to be altruistic."
This sounds reasonable if you consider only one generation, or only the individual. But if you consider the whole group or species in the long run, the effect you see is exactly what you describe, i.e. groups that encourage this kind of behavior will outcompete groups that don't. So for a species to survive, it is much more important that the group survives than just an individual. If the individual survives, but it can't reproduce, then the species won't survive in the long term.
I think the important thing is to determine what behavior better represents reality, meaning what would explain the survival of current species on earth, not just try to confirm survival of the fittest for an individual.
> IIRC, the primary reason that group selection is thought to be wrong is that it (apparently) can't yield an Evolutionarily Stable Strategy (ESS) -- it will always be better for the persistence of any individual's DNA if that individual refuses to be altruistic.
"always will be better" seems to assume that group viability has no effect on individual survival.
While it's best to be the most selfish in the group, that doesn't imply that it's good enough. You need to also survive, and some groups help with that by having some altruism.
Kin selection: organism X helps organism Y because it improves the prospects for the part of X's DNA that Y also has. The more related X is to something, the more willing X is to sacrifice itself for it. The most extreme example is also the most familiar: each of your cells has DNA identical to each of your other cells (if all is well). So a cell is completely willing to kill itself for the "collective", even at the expense of its own ability to reproduce. A less extreme example is that of a woman declining to pursue kids of her own in order to help tend her sister's, which could be adaptive when, e.g., food is scarce.
Group selection: members of a particular group (e.g., a tribe) are willing to engage in altruistic actions (e.g., suicidal defense of said tribe pre-procreation) even though doing so maladaptive at the level of the individual's DNA. This kind of cooperation is adaptive for the group as a whole, but not in the least for the individual. Groups that encourage this kind of behavior will outcompete groups that don't, so groups are selected for this trait.
IIRC, the primary reason that group selection is thought to be wrong is that it (apparently) can't yield an Evolutionarily Stable Strategy (ESS) -- it will always be better for the persistence of any individual's DNA if that individual refuses to be altruistic.