[js1138]

I'm not sure what you said is even English. Could yo provide some concrete examples?

[Fester Chugabrew]

You are asking for some concrete examples of experiential or environmental factors that can lessen the benefits of surviving selection in cases where the population is incapable of reproducing, right?

I will try to do that, but, for the sake of maintaining a proper understanding between us, please tell me how you want to use the word "population" in this context, and I'll go at it from there.

At any reat, what I have in mind are certain catastrophic phemenomena that could wipe out a population regardless of its ability to survive in these conditions.