Sure, my example is way over-simplified, and group B will always have a higher mortality rate, which could be disastrous for them in a pandemic with a high death rate. But the survivors of that pandemic are going to think themselves extra special and try to repopulate the globe again.

Using the tools provided by Group A, of course.

Evolution also in action - different strategies for responding to evolutionary pressure.

Group A: moves cautiously and with extensive forethought. Acts slowly but with higher success rate and longevity. Reproduces below replacement level.

Group B: Shotgun approach, devil-may-care attitude. Pops out kids like a mushroom releasing spores. Overwhelms evolutionary pressure by sheer volume. Some offspring migrate over to Group A, keeping the two groups in some sort of balance, if not harmony.

Is that what happens there? I'd like to see that.

'lost' = 'used'?

As in, your brother made a rat-tail out of it and snapped you with it, leading to tears, a fight, and both of you getting in trouble?

'cause that's how it happened with me and my brothers.