How do adaptations contribute to species survival?

In short we have a a very powerful process at work, Natural Selection, perhaps not entirely the only process, but the most formidable in explaining all the diversity of life.

Natural selection is the gradual, non-random process by which biological traits become either more or less common in a population as a function of differential reproduction of their bearers. It is a key mechanism of evolution.

Please review the links below in sources for a better review of adaptation.