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In evolutionary biology, 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.
In biology, two related species or populations are considered sympatric when they exist in the same geographic area and thus frequently encounter one another. [1] An initially interbreeding population that splits into two or more distinct species sharing a common range exemplifies sympatric speciation .
Rapid sympatric speciation can take place through polyploidy, such as by doubling of chromosome number; the result is progeny which are immediately reproductively isolated from the parent population. New species can also be created through hybridization , followed by reproductive isolation, if the hybrid is favoured by natural selection.
Allopatric speciation, in which two populations of the same species are geographically isolated from one another by an extrinsic barrier and evolve intrinsic (genetic) reproductive isolation. Peripatric speciation, in which a small group of a population is separated from the main body and experiences genetic drift.
Just as sunlight can appear as a dim crack in the sky before clouds part, the coarse boundaries of ecotypes may appear as a separation of principle component clusters before speciation. — David B. Lowry, Ecotypes and the controversy over stages in the formation of new species, Biological Journal of the Linnean Society.
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.
Sympatric speciation, from its beginnings with Darwin (who did not coin the term), has been a contentious issue. [41] [4]: 125 Mayr, along with many other evolutionary biologists, interpreted Darwins's view of speciation and the origin of biodiversity as arising by species entering new ecological niches—a form of sympatric speciation. [1]
The pathways that lead from disruptive selection to sympatric speciation seldom are prone to deviation; such speciation is a domino effect that depends on the consistency of each distinct variable. These pathways are the result of disruptive selection in intraspecific competition ; it may cause reproductive isolation , and finally culminate in ...