Editing Disruptive selection (section)

== Overview ==
[[Natural selection]] is known to be one of the most important biological processes behind [[evolution]] {{Dubious| Natural Selection Vs. Genetic Drift|date=May 2025}}. There are many variations of traits, and some cause greater or lesser [[reproductive success]] of the individual. The effect of selection is to promote certain [[allele]]s, traits, and individuals that have a higher chance to survive and reproduce in their specific environment. Since the environment has a [[carrying capacity]], nature acts on this mode of selection on individuals to let only the most fit offspring survive and reproduce to their full potential. The more advantageous the trait is the more common it will become in the population. Disruptive selection is a specific type of natural selection that actively selects against the intermediate in a population, favoring both extremes of the spectrum.

Disruptive selection is inferred to oftentimes lead to [[sympatric speciation]] through a [[phyletic gradualism]] mode of evolution. Disruptive selection can be caused or influenced by multiple factors and also have multiple outcomes, in addition to speciation. Individuals within the same environment can develop a preference for extremes of a trait, against the intermediate. Selection can act on having divergent body morphologies in accessing food, such as beak and dental structure. It is seen that often this is more prevalent in environments where there is not a wide clinal range of resources, causing [[Underdominance|heterozygote disadvantage]] or selection favoring homozygotes.

[[Niche partitioning]] allows for selection of differential patterns of resource usage, which can drive speciation. To the contrast, niche conservation pulls individuals toward ancestral ecological traits in an evolutionary tug-of-war. Also, nature tends to have a 'jump on the band wagon' perspective when something beneficial is found. This can lead to the opposite occurring with disruptive selection eventually selecting against the average; when everyone starts taking advantage of that resource it will become depleted and the extremes will be favored. Furthermore, gradualism is a more realistic view when looking at speciation as compared to punctuated equilibrium.

Disruptive selection can initially rapidly intensify divergence; this is because it is only manipulating alleles that already exist. Often it is not creating new ones by mutation which takes a long time. Usually complete reproductive isolation does not occur until many generations, but behavioral or morphological differences separate the species from reproducing generally. Furthermore, generally hybrids have reduced fitness which promotes reproductive isolation.<ref>Abrams, P.A., Leimar, O., Rueffler, C., Van Dooren, J.M. 2006. Disruptive selection and then what? Trends in Ecology & Evolution Vol. 21 Issue 5:238–245.</ref><ref>{{cite journal | last1 = Boam | first1 = T.B. | last2 = Thoday | first2 = J.M. | year = 1959 | title = Effects of disruptive selection: Polymorphism and divergence without isolation | doi = 10.1038/hdy.1959.23| journal = Heredity | volume = 13 | issue = 2| pages = 205–218 | doi-access = free }}</ref><ref>{{cite journal | last1 = Bolnick | first1 = D.I. | year = 2004 | title = Can Intraspecific competition drive disruptive Selection? An experimental test in natural population of sticklebacks | journal = Evolution | volume = 58 | issue = 3| pages = 608–618 | doi=10.1111/j.0014-3820.2004.tb01683.x| pmid = 15119444 | doi-access = free }}</ref><ref>{{cite journal | last1 = Cook | first1 = L.M. | last2 = Grant | first2 = B.S. | last3 = Mallet | first3 = J. | last4 = Saccheri | first4 = I.J. | year = 2012 | title = Selective bird predation on the peppered moth: the last experiment of Michael Majerus | journal = Biology Letters | volume = 8 | issue = 4| pages = 609–612 | doi = 10.1098/rsbl.2011.1136 | pmid=22319093 | pmc=3391436}}</ref><ref>{{cite journal | last1 = DeLeon | first1 = L.F. | last2 = Harrel | first2 = A. | last3 = Hendry | first3 = A.P. | last4 = Huber | first4 = S.K. | last5 = Podos | first5 = J. | year = 2009 | title = Disruptive Selection in a Bimodal Population of Darwin's Finches | doi = 10.1098/rspb.2008.1321 | pmid = 18986971 | journal = Proceedings: Biological Sciences | volume = 276 | issue = 1657| pages = 753–759 | pmc = 2660944 }}</ref><ref>{{cite journal | last1 = Kingsolver | first1 = J.G. | last2 = Pfenning | first2 = David W. | year = 2007 | title = Patterns and Power of Phenotypic Selection in Nature | journal = BioScience | volume = 57 | issue = 7| pages = 561–572 | doi=10.1641/b570706| doi-access = free }}</ref><ref>{{cite journal | last1 = Rice | first1 = W.R. | last2 = Salt | first2 = G.W. | year = 1988 | title = Speciation Via Disruptive Selection on Habitat Preference: Experimental Evidence | journal = The American Naturalist | volume = 131 | issue = 6| pages = 911–917 | doi=10.1086/284831| s2cid = 84876223 }}</ref><ref>{{cite journal | last1 = Seehausen | first1 = M. E. | last2 = Van Alphen | first2 = J.J.M. | year = 1999 | title = Can sympatric speciation by disruptive sexual selection explain rapid evolution of cichlid diversity in Lake Victoria? | journal = Ecology Letters | volume = 2 | issue = 4| pages = 262–271 | doi=10.1046/j.1461-0248.1999.00082.x}}</ref><ref>{{cite journal | last1 = Smith | first1 = T.B. | year = 1993 | title = Disruptive selection and the genetic basis of bill size polymorphism in the African finch Pyrenestes | journal = Letters to Nature | volume = 363 | issue = 6430| pages = 618–620 | doi=10.1038/363618a0| bibcode = 1993Natur.363..618S | s2cid = 4284118 }}</ref>