Comparison of allopatric, peripatric, parapatric and sympatric speciation.

Sympatric Speciation is the genetic divergence of multiple populations (from a single parent species) inhabiting the same geographic region; such that those populations become different species. Etymologically, sympatry is derived from the roots sym- (meaning same, alike, similar, or fellow) and -patry (meaning homeland or fatherland). Image File history File links Speciation_modes. ... Image File history File links Speciation_modes. ... Allopatric speciation, also known as geographic speciation, occurs when populations physically isolated by an extrinsic barrier evolve intrinsic (genetic) reproductive isolation such that if the barrier between the populations breaks down, individuals of the two populations can no longer interbreed. ... Peripatric speciation (also known as Parapatry) is a type of speciation in the theory of natural selection. ... Parapatric speciation is a form of speciation in which the evolution of reproductive isolating mechanisms occurs when a population enters a new niche or habitat within the range of the parent species. ... Charles Darwins first sketch of an evolutionary tree from his First Notebook on Transmutation of Species (1837) Speciation is the evolutionary process by which new biological species arise. ... Etymology is the study of the origins of words. ...

Sympatry is one of four theoretical models for the phenomenon of speciation. In complete contrast to allopatry, species undergoing sympatric speciation are not geographically isolated by, for example, a mountain or a river. Charles Darwins first sketch of an evolutionary tree from his First Notebook on Transmutation of Species (1837) Speciation is the evolutionary process by which new biological species arise. ... Allopatric speciation, also known as geographic speciation, occurs when populations physically isolated by an extrinsic barrier evolve intrinsic (genetic) reproductive isolation such that if the barrier between the populations breaks down, individuals of the two populations can no longer interbreed. ...

Debated almost since the beginning of popular evolutionary thought, sympatric speciation is still a highly contentious issue. By 1980 the theory was largely unfavourable given the void of empirical evidence available, and more critically the conditions scientists expect to be required. Ernst Mayr, one of the foremost thinkers on evolution, completely rejected sympatry outright, ushering in a climate of hostility towards the theory. Since the 1980s, a more progressive ideology has been adopted. While still debatable, well documented empirical evidence now exists, and the development of sophisticated theories incorporating multilocus genetics have followed. Year 1980 (MCMLXXX) was a leap year starting on Tuesday (link displays the 1980 Gregorian calendar). ... This article has been identified as possibly containing errors. ... This article does not cite any references or sources. ...

A number of models have been proposed to account for this mode of speciation. The most popular, disruptive speciation, was first put forward by John Maynard Smith in 1962. 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. Professor John Maynard Smith[1], F.R.S. (6 January 1920 – 19 April 2004) was a British evolutionary biologist and geneticist. ... Year 1962 (MCMLXII) was a common year starting on Monday (the link is to a full 1962 calendar) of the Gregorian calendar. ... This article or section does not cite its references or sources. ... For the hard rock band, see Allele (band). ... An organism is a heterozygote or heterozygous for a gene or trait if it has different alleles at the genes locus for each homologous chromosome. ... Darwins illustrations of beak variation in the finches of the Galápagos Islands, which hold 13 closely related species that differ most markedly in the shape of their beaks. ...

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. ^[1] Genera Geospiza Camarhynchus Certhidea Pinaroloxias Darwins finches (also known as the Galápagos Finches) are 13 or 14 different but closely related species of finches Charles Darwin collected on the Galápagos Islands during the voyage of the Beagle. ... Santa Cruz Island is one of the Galápagos Islands with an area of 986 km² and a maximum altitude of 864 metres. ... Individuals in the mollusk species Donax variabilis show diverse coloration and patterning in their phenotypes. ... Bird song refers to the sounds, usually melodious to the human ear, made by many birds of the order Passeriformes as a form of communication. ...

Rhagoletis pomonella, the apple maggot, may be currently undergoing sympatric or, more precisely, heteropatric (see heteropatry) speciation. The apple feeding race of this species appears to have spontaneously emerged from the hawthorn feeding race in the 1800 - 1850 AD time frame, after apples were first introduced into North America. The apple feeding race does not now normally feed on hawthorns, and the hawthorn feeding race does not now normally feed on apples. This may be an early step towards the emergence of a new species. ^{[2] [3] [4] [5]} Binomial name Rhagoletis pomonella Walsh, 1867 The apple faggot (Rhagoletis pomonella), also known as railroad worm, is a pest of several fruits, mainly apples. ... Heteropatry is a concept the refines our notion of sympatry in recognizing that though two variants (genotypes, strains, races) of a population coexist in the same geographical area, these variants are behaviorally separated in terms of exploiting niches that are interwoven to produce a heterogeneous or patchwork landscape. ... Species See text Crataegus (Hawthorn) is a large genus of in the family Rosaceae, native to temperate regions of the Northern Hemisphere in Europe, Asia and North America. ... North America North America is a continent[1] in the Earths northern hemisphere and (chiefly) western hemisphere. ... Species See text Crataegus (Hawthorn) is a large genus of in the family Rosaceae, native to temperate regions of the Northern Hemisphere in Europe, Asia and North America. ...

Allochrony offers some empirical evidence that sympatric speciation has taken place, as many examples exist of recently diverged (sister taxa) allochronic species. The term allochrony is used in ecology to describe a situation where two biological entities (typically species) occur in the same area, and are thus sympatric, but are never or rarely active simultaneously. ... This cladogram shows the relationship among various insect groups. ...

Sympatric speciation events are vastly most common in plants when they double or triple their number of chromosomes, resulting in a condition called polyploidy. Charles Darwins first sketch of an evolutionary tree from his First Notebook on Transmutation of Species (1837) Speciation is the evolutionary process by which new biological species arise. ... Polyploidy refers to cells or organisms that contain more than two copies of each of their chromosomes. ...

A rare example of sympatric speciation in animals is the divergence of "resident" and "transient" Orca forms in the northeast Pacific^[6]. Resident and transient orcas inhabit the same waters, but avoid each other and do not interbreed. The two forms hunt different prey species and have different diets, vocal behaviour, and social structures. Binomial name Orcinus orca Linnaeus, 1758 Orca range (in blue) The Orca or Killer Whale (Orcinus orca) is the largest species of the oceanic dolphin family (Delphinidae). ...

See also

• Adaptive radiation
• Heteropatry
• Hybrid speciation
• Adaptive radiation
• Cladistics
• Phylogenetics
• Taxonomy

Four of the 13 finch species found on the Galápagos Archipelago, and thought to have evolved by an adaptive radiation that diversified their beak shapes to adapt them to different food sources. ... Heteropatry is a concept the refines our notion of sympatry in recognizing that though two variants (genotypes, strains, races) of a population coexist in the same geographical area, these variants are behaviorally separated in terms of exploiting niches that are interwoven to produce a heterogeneous or patchwork landscape. ... Hybridization between two different species sometimes leads to a distinct phenotype. ... Four of the 13 finch species found on the Galápagos Archipelago, and thought to have evolved by an adaptive radiation that diversified their beak shapes to adapt them to different food sources. ... It has been suggested that Clade be merged into this article or section. ... Phylogenetic groups, or taxa, can be monophyletic, paraphyletic, or polyphyletic. ... Look up taxonomy in Wiktionary, the free dictionary. ...

Reference

1. ^ *Huber, S.K.; L.F. De León & A.P. Hendry et al. (2007), "Reproductive isolation of sympatric morphs in a population of Darwin's finches", Proc. Biol. Sci., PMID 17504742
2. ^ McPheron et al. 1988. Nature 336:64-66
3. ^ Smith, D.C. 1988. Nature 336:66-67
4. ^ Feder et al. 1988. Nature 336:61-64
5. ^ Sympatric speciation in Nicaraguan crater lake cichlid fish. By: Barluenga, Marta; Stölting, Kai N.; Salzburger, Walter; Muschick, Moritz; Meyer, Axel. Nature, 2/9/2006, Vol. 439 Issue 7077, p719-723.
6. ^ Burden et al.: Resident And Transient-Type Killer Wales SC/56/SM15.