Stabilizing selection (not to be confused with negative or purifying selection) is a type of natural selection in which the population mean stabilizes on a particular non-extreme trait value. This is thought to be the most common mechanism of action for natural selection because most traits do not appear to change drastically over time. Stabilizing selection commonly uses negative selection (a.k.a. purifying selection) to select against extreme values of the character. Stabilizing selection is the opposite of disruptive selection. Instead of favoring individuals with extreme phenotypes, it favors the intermediate variants. Stabilizing selection tends to remove the more severe phenotypes, resulting in the reproductive success of the norm or average phenotypes. This means that most common phenotype in the population is selected for and continues to dominate in future generations.
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Stabilizing selection in the context of Ivan Schmalhausen
Ivan Ivanovich Schmalhausen (Russian: Ива́н Ива́нович Шмальга́узен; 23 April 1884 – 7 October 1963) was a Russian and Soviet zoologist and evolutionary biologist of German descent. He developed the theory of stabilizing selection, and took part in the development of the modern evolutionary synthesis.
He is remembered, among other things, for Schmalhausen's law, which states that a population at its limit of tolerance in one aspect is vulnerable to small differences in any other aspect.
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