All members of a population share many characteristics in common. For example, all finches in a particular forest are alike in many ways. But if many hard-to-shell seeds are found in the forest, those finches with stronger, more conical bills will have better rates of reproduction and survival than finches with thin bills. Therefore, a conical, stout bill can be considered an adaptation to that forest environment. Any specialized characteristic that permits an individual to survive and reproduce is called an adaptation. Adaptations may result either from an individual's genetic heritage or from its ability to learn. Since successful genetic adaptations are more likely to be passed from generation to generation through the survival of better adapted organisms, adaptation can be viewed as the force that drives biological evolution.