[Answer] What prevents speciation from occurring in sympatric populations?

Answer: Gene Flow
What prevents speciation from occurring in sympatric populations?

Sympatric speciation is the evolution of a new species from a surviving ancestral species while both continue to inhabit the same geographic region. In evolutionary biology and biogeography sympatric and sympatry are terms referring to organisms whose ranges overlap so that they occur together at least in some places. If these organisms are closely related (e.g. sister species) such a distribution m…

Sympatric speciation is the evolution of a new species from a surviving ancestral species while both continue to inhabit the same geographic region. In evolutionary biology and biogeography sympatric and sympatry are terms referring to organisms whose ranges overlap so that they occur together at least in some places. If these organisms are closely related (e.g. sister species) such a distribution may be the result of sympatric speciation. Etymologically sympatry is derived from the Greek roots συν (“together”) and πατρίς (“homeland”). The term was coined by Edward Bagnall Poulton in 1904 who explains the derivation. Sympatric speciation is one of three traditional geographic modes of speciation. Allopatric speciation is the evolution of species caused by the geographic isolation of two or more populations of a species. In this case divergence is facilitated by the absence of gene flow. Parapatric speciation is the evolution of geographically adjacent populations into distinct species. In this case divergence occurs despite limited interbreeding where the two diverging groups come into contact. In sympatric speciation there is no geographic constraint to interbreeding. These categories are special cases of a continuum from zero (sympatric) to complete (allopatric) spatial segregation of diverging groups. In multicellular eukaryotic organisms sympatric speciation is a plausible process that is known to occur but the frequency with which it occurs is not known. In bacteria however the analogous process (defined as “the origin of new bacterial species that occupy definable ecological niches”) might be more common because bacteria are less constrained by the homogenizing effects of sexual reproduction and are prone to comparatively dramatic and rapid genetic change through horizontal gene transfer.

Sympatric speciation events are quite common in plants which are prone to acquiring multiple homologous sets of chromosomes resulting in polyploidy . The polyploid offspring occupy the same environment as the parent plants (hence sympatry) but are reproductively isolated.

Sympatric speciation events are quite common in plants which are prone to acquiring multiple homologous sets of chromosomes resulting in polyploidy . The polyploid offspring occupy the same environment as the parent plants (hence sympatry) but are reproductively isolated. A number of models have been proposed for alternative modes of sympatric speciation. The most popular which invokes the disruptive selection model was first put forward by John Maynard Smith in 1966. Maynard Smith suggested that homozygous individuals may under particular environmental conditions have a greater fitness than those with alleles heterozygous for a certain trait. Under the mechanism of natural selection therefore homozygosity would be favoured over heterozygosity eventually leading to speciation. Sympatric divergence could also result from the sexual conflict . Disruption may also occur in multiple-gene traits. The medium ground finch (Geospiza fortis) is showing gene pool divergence in a population on Santa Cruz Island . Beak morphology conforms to two different size ideals while intermediate individuals are selected against. Some characteristics (termed magic traits ) such as beak morphology may drive speciation because they also affect mating signals. In this case different beak phenotypes may result in different bird calls providing a barrier to exchange between the gene pools. A somewhat analogous system has been reported in horseshoe bats in which echolocation call frequency appears to be a magic trait. In these bats the constant frequency component of the call not o… Read more on Wikipedia

In biology two related species or populations are considered sympatric when they exist in the same geographic area and thus frequently encounter one another. An initially interbreeding population that splits into two or more distinct species sharing a common range exemplifies sympatric speciation .Such speciation may be a product of reproductive isolation – which prevents hybrid offspring …

59 rows · Sat Dec 19 2020 13:30:00 GMT-0500 (Eastern Standard Time) · Sympatric populations of genetically differentiated plants flower at different …

Sympatric speciation – Wikipedia

Allopatric speciation – Wikipedia

Reproductive isolation – Wikipedia

Sympatry – Wikipedia

Speciation is the evoluti…

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