Editing Evolutionarily stable strategy (section)

== Vs. evolutionarily stable state ==
In population biology, the two concepts of an ''evolutionarily stable strategy'' (ESS) and an ''[[evolutionarily stable state]]'' are closely linked but describe different situations.

In an evolutionarily stable ''strategy,'' if all the members of a population adopt it, no mutant strategy can invade.<ref name="JMS82"/> Once virtually all members of the population use this strategy, there is no 'rational' alternative. ESS is part of classical [[game theory]].

In an evolutionarily stable ''state,'' a population's genetic composition is restored by selection after a disturbance, if the disturbance is not too large. An evolutionarily stable state is a dynamic property of a population that returns to using a strategy, or mix of strategies, if it is perturbed from that initial state. It is part of [[population genetics]], [[dynamical system]], or [[evolutionary game theory]]. This is now called convergent stability.<ref>{{Cite journal |last1=Apaloo |first1=J. |last2=Brown |first2=J. S. |last3=Vincent |first3=T. L. |date=2009 |title=Evolutionary game theory: ESS, convergence stability, and NIS |url=http://www.evolutionary-ecology.com/abstracts/v11/2445.html |journal=Evolutionary Ecology Research |volume=11 |pages=489–515 |access-date=2018-01-10 |archive-url=https://web.archive.org/web/20170809115301/http://www.evolutionary-ecology.com/abstracts/v11/2445.html |archive-date=2017-08-09 |url-status=dead }}</ref>

B. Thomas (1984) applies the term ESS to an individual strategy which may be mixed, and evolutionarily stable population state to a population mixture of pure strategies which may be formally equivalent to the mixed ESS.<ref>{{cite journal |doi=10.1016/0040-5809(84)90023-6 |author=Thomas, B. |title=Evolutionary stability: states and strategies |journal=Theor. Popul. Biol. |volume=26 |issue=1 |pages=49–67 |year=1984 |bibcode=1984TPBio..26...49T }}</ref>

Whether a population is evolutionarily stable does not relate to its genetic diversity: it can be genetically monomorphic or [[Polymorphism (biology)|polymorphic]].<ref name="JMS82"/>