It is actually fairly common to see sympatric speciation when disruptive selection is supporting two morphs, specifically when the phenotypic trait effects fitness rather than mate choice.
22.
While it is true that disruptive selection can lead to speciation, this is not as quick or straightforward of a process as other types of speciation or evolutionary change.
23.
This is largely because the results of disruptive selection are less stable than the results of directional selection ( directional selection favors individuals at only one end of the spectrum ).
24.
They conjectured that disruptive selection produced by variation in the environment could result in an evolutionary transition from ESD to GSD ( Bull, Vogt, and Bulmer, 1982 ).
25.
Once the polymorphisms are maintained in the population, if assortative mating is taking place, then this is one way that disruptive selection can lead to the direction of sympatric speciation.
26.
Genic capture was proposed as a simpler alternative to another theory explaining the lek paradox that proposed that sexual selection creates disruptive selection, i . e . positive selection for genetic variance.
27.
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.
28.
"' Disruptive selection "', also called "'diversifying selection "', describes changes in population genetics in which extreme values for a trait are favored over intermediate values.
29.
Both gamete competition and gamete limitation assume that anisogamy originated through disruptive selection acting on an ancestral isogamous population with external fertilization, due to a trade-off between larger gamete number and gamete size ( which in turn affects zygote survival ), because the total resource one individual can invest in reproduction is assumed to be fixed.
30.
He has pioneered experiments into disruptive selection ( selection in the same population for both extremes and against intermediates ), and ( again contrary to theoretical expectation ), showed such selection could be extremely effective, increasing variance, establishing and maintaining polymorphisms, and, if the selected individuals were allowed to choose their mates, dividing the population into two partially isolated parts, something which is a step towards speciation.
