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Speciation by reinforcement relies directly on selection to favor an increase in prezygotic isolation, [1] and the nature of selection's role in reinforcement has been widely discussed, with models applying varying approaches. [29] Selection acting on hybrids can occur in several different ways.
A prediction of reinforcement is that assortive mating should be common in hybrid zones; a prediction that was confirmed in 19 of the 37 cases. [6] A survey of the rates of speciation in fish and their associated hybrid zones found similar patterns in sympatry, supporting the occurrence of reinforcement. [68]
Reinforcement favoring reproductive isolation is required for both parapatric and sympatric speciation. Without reinforcement, the geographic area of contact between different forms of the same species, called their "hybrid zone", will not develop into a boundary between the different species.
1. An extrinsic barrier separates a species population into two but they come into contact before reproductive isolation is sufficient to result in speciation. The two populations fuse back into one species 2. Speciation by reinforcement 3. Two separated populations stay genetically distinct while hybrid swarms form in the zone of contact 4.
It also plays a role in speciation by reinforcement in such that allopatric populations overlapping in sympatry exhibit greater trait divergence. [4] The results of numerous studies contribute evidence that character displacement often influences the evolution of resource acquisition among members of an ecological guild. [5]
Reinforcement is the process by which natural selection reinforces reproductive isolation. In sympatry, reinforcement increases species discrimination and sexual adaptation in order to avoid maladaptive hybridization and encourage speciation. If hybrid offspring are either sterile or less-fit than non-hybrid offspring, mating between members of ...
A simplification of an allopatric speciation experiment where two lines of fruit flies are raised on maltose and starch media. Laboratory experiments of speciation have been conducted for all four modes of speciation: allopatric, peripatric, parapatric, and sympatric; and various other processes involving speciation: hybridization, reinforcement, founder effects, among others.
Allopatric speciation (from Ancient Greek ἄλλος (állos) 'other' and πατρίς (patrís) 'fatherland') – also referred to as geographic speciation, vicariant speciation, or its earlier name the dumbbell model [1]: 86 – is a mode of speciation that occurs when biological populations become geographically isolated from each other to an extent that prevents or interferes with gene flow.