Mr. Moll, the illustration of light and dark colored moths surviving on either light or dark bark of trees on which they exist, acting as camouflage, hiding them from predators may be the type of thing you are talking about when you refer to selective pressure, variation, and reproduction. It also may illustrate the constraints of genetics where adaptation is limited to a restricted environment and where much wider environmental events — like forest fires — overwhelm the genetic abilities to respond. In higher life forms, for example, the lions always seem to have enough to eat no matter how far the antelope have evolved. It can be argued , of course, that the herd survives because of the sacrifice oft he one, but that does not necessarily prove the inferiority of the one nor the superiority of the other. It may show the variations between good luck and bad luck. Nevertheless, it does illustrate the dog-eat-dog nature of survival of the fittest. Whatever this discussion has to do with my little story escapes me.