A type of selection that favours organisms with a high biotic potential (r value). Organisms that are r selected (r strategists) are able to colonize a habitat rapidly, utilizing the food and other resources before other organisms are established and begin to compete. The r strategists tend to be relatively small organisms with short life spans (e.g. bacteria) and often live in temporary or unstable environments; characteristically their survival depends on their ability to produce large numbers of offspring rather than on their ability to compete. Compare K selection. See also population dynamics; survival curve.