Shifting balance theory Shifting balance theory The shifting balance theory is a theory of evolution proposed in 1932 by Sewall Wright, suggesting that adaptive evolution may proceed most quickly when a population divides into subpopulations with restricted gene flow. The name of the theory is borrowed from Wright's metaphor of fitness landscapes (evolutionary landscapes), attempting to explain how a population may move across an adaptive valley to a higher adaptive peak. According to the theory, this movement occurs in three steps: Although shifting balance theory has been influential in evolutionary biology, inspiring the theories of quantum evolution and punctuated equilibrium, little empirical evidence
Evolutionary game theory insect species. A difficulty of the theory of evolution, recognised by Darwin himself, was the problem of altruism. If the basis for selection is at individual level, altruism makes no sense at all. But universal selection at the group level (for the good of the species, not the individual) fails to pass the test of the mathematics of game theory and is certainly not the general case in nature. Yet in many social animals, altruistic behaviour exists. The solution to this paradox can be found in the application of evolutionary game theory to the prisoner's dilemma game – a game