A principal feature of the evolutionary theory propounded by Niles Eldredge and Stephen J. Gould, in which species' change is represented as a form of Darwinian gradualism, punctuated by periods of rapid evolutionary change. It is a revision of Darwinian theory proposing that the creation of new species through evolutionary change occurs not at slow constant rates over millions of years but rather in rapid bursts over periods as short as thousands of years which are then followed by long periods of stability during which organisms undergo little further change.