Shifting balance theory

1. Genetic drift allows a locally adapted subpopulation to move across an adaptive valley to the base of a higher adaptive peak.
2. Natural selection will move the subpopulation up the higher peak.
3. This new superiorly adapted subpopulation may then expand its range and outcompete or interbreed with other subpopulations, causing the spread of new adaptations and movement of the global population toward the new fitness peak.

Although shifting balance theory has been influential in evolutionary biology, inspiring the theories of quantum evolution and punctuated equilibrium, little empirical evidence exists to support the shifting balance process as an important factor in evolution.