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 Theory (journal) Hypothesis. He also introduced what would become known as Van Valen’s law in this very same paper. The original name – law of constant extinction – states that “the probability of extinction for species and larger evolutionary groups bears no relation to how long it may have already existed”. He also contended that “The fossil record shows that lineages become neither more extinction-resistant nor more vulnerable over time”. One of the journals that originally rejected Van Valen’s article, Nature (journal) , recognized the importance of his work by confirming his work with several follow-up studies. "Evolutionary Theory" is copyrighted by