>All other rules/ethics seem to be dependent on resource scarcity

That doesn't make the rest of the ethics (as a rule and mechanism) any less useful to help nurture the species and its intelligence.

It just makes them not absolute but dynamic and condition dependent. But given a condition (e.g. resource scarcity) the appropriate ethics retain the utility we talk about.

Groups don't follow rules as such, group behaviours emerge from the interaction of individual behaviours.

As to whether all groups display those rules - I suspect not - though it rather does depend on how you define a group - the definition of group probably has some sort of colloboration built in ( as oppose to a bunch of indviduals that happen to live in the same geographic area ).