Competition

Competition amongst organisms in the same environment is a major force that drives species to adapt and evolve. Competition is at the foundation of the saying "survival of the fittest", as those who are best fit can compete with other organisms in their environment better and have a better chance of reproducing. Organisms in competition with each other are battling to gain control of a particular resource, whether that be food, shelter, or some other resource. The battle for these resources forces organisms to adapt and overcome the challenges that they may face when vying for control of these resources. If one organism is unfit to compete with another, it will lose easy access to resources in the area, and unless the less-fit organism can move to a new area where it can access the same resources without such fierce competition, the numbers of that organism will decline and may eventually go extinct if it cannot adapt.