a) Sure, fitness can take an expansive definition. The question is whether sexual selection is a separate force from natural selection. If so, fitness would bre

a) Sure, fitness can take an expansive definition. The question is whether sexual selection is a separate force from natural selection. If so, fitness would break down into environmental fitness and reproductive fitness. b) the height of the survival bar of quite variable. Suppose you've got a decent niche that holds steady for a few millennia. Or your an invasive species with no real competition but others of your kind. In either case there's plenty of space for variation to arise which won't depend on natural selection pressure.