Sympatry

Information about Sympatry

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).

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.

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.

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.

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]

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]

Allochrony offers some empirical evidence that sympatric speciation has taken place, as many examples exist of recently diverged (sister taxa) allochronic species.

Sympatric speciation events are vastly most common in plants when they double or triple their number of chromosomes, resulting in a condition called polyploidy.

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.

References

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.

Etymology is the study of the history of words - when they entered a language, from what source, and how their form and meaning have changed over time.

In languages with a long written history, etymology makes use of philology, the study of how words change from culture to
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Speciation is the evolutionary process by which new biological species arise. There are four modes of natural speciation, based on the extent to which speciating populations are geographically isolated from one another:
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Allopatric speciation, also known as geographic speciation, is the phenomenon where huge biological populations are physically isolated by an extrinsic barrier and evolve intrinsic (genetic) reproductive isolation, such that if the barrier breaks down, individuals of the
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19th century - 20th century - 21st century
1950s 1960s 1970s - 1980s - 1990s 2000s 2010s
1977 1978 1979 - 1980 - 1981 1982 1983

Year 1980 (MCMLXXX
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Ernst Walter Mayr (July 5, 1904, Kempten, Germany – February 3, 2005, Bedford, Massachusetts U.S.), was one of the 20th century's leading evolutionary biologists. He was also a renowned taxonomist, tropical explorer, ornithologist, historian of science, and naturalist.
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worldwide view of the subject.
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Professor John Maynard Smith,^[1] F.R.S. (6 January 1920 – 19 April 2004) was a British evolutionary biologist and geneticist. Originally an aeronautical engineer during the Second World War, he then took a second degree in genetics under the well-known biologist J.
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19th century - 20th century - 21st century
1930s 1940s 1950s - 1960s - 1970s 1980s 1990s
1959 1960 1961 - 1962 - 1963 1964 1965

Year 1962 (MCMLXII
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Zygosity refers to the genetic condition of a zygote. In genetics, zygosity describes the similarity or dissimilarity of DNA between homologous chromosomes at a specific allelic position or gene.

Every gene in a diploid organism has two alleles at the gene's locus.
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For the hard rock band, see .

An allele (Pronounced: /əˈlil/) is a viable DNA (deoxyribonucleic acid) coding that occupies a given locus (position) on a chromosome.
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Natural selection is the process by which favorable traits that are heritable become more common in successive generations of a population of reproducing organisms, and unfavorable traits that are heritable become less
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Darwin's 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. Thirteen reside on the Galápagos Islands and one on Cocos Island.
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Santa Cruz Island is one of the Galápagos Islands with an area of 986 km² and a maximum altitude of 864 metres.

Situated in the centre of the archipelago, Santa Cruz Canton is the second largest island after Isabela.
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phenotype describes the total physical appearance of an organism, as opposed to its genotype. This genotype-phenotype distinction was proposed by Wilhelm Johannsen in 1911 to make clear the difference between an organism's heredity and what that heredity produces.
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Bird songs are certain vocal sounds that birds make. In non-technical use, these are the bird sounds that are melodious to the human ear. In ornithology, bird 'songs' are often distinguished from shorter sounds, which may be termed 'calls'.
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R. pomonella

Binomial name
Rhagoletis pomonella
Walsh, 1867

The apple maggot (Rhagoletis pomonella), also known as railroad worm, is a pest of several fruits, mainly apples.
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Heteropatry is a concept that 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
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Crataegus
Tourn. ex L.

Species
See text
Crataegus (Hawthorn) is a large genus of shrubs and trees in the family Rosaceae, native to temperate regions of the Northern Hemisphere in Europe, Asia and North America.
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North America is a continent ^[1] in the Earth's northern hemisphere and (chiefly) western hemisphere. It is bordered on the north by the Arctic Ocean, on the east by the North Atlantic Ocean, on the southeast by the Caribbean Sea, and on the south and west
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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.
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Cladistics is a philosophy of classification that arranges organisms only by their order of branching in an evolutionary tree and not by their morphological similarity, in the words of Luria et al. (1981).
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Polyploidy is the condition of some biological cells and organisms manifested by the presence of more than two homologous sets of chromosomes. Polyploid types are termed according to the number of chromosome sets in the nucleus: triploid (three sets; 3x),
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Orcinus

Species: O. orca

Binomial name
Orcinus orca
Linnaeus, 1758

Orca range (in blue)

The
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Adaptive radiation describes the rapid speciation of a single or a few species to fill many ecological niches. This is an evolutionary process driven by natural selection, successful and novel adaptation, and sometimes by mutation (heritable/genetic variation).
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Hybrid speciation is the process wherein hybridization between two different closely related species leads to a distinct phenotype. This phenotype in very rare cases can also be fitter than the parental lineage and as such natural selection may then favor these individuals.
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Herod_Archelaus

• • [ e] Speciation guide
Basic concepts:	Species • Chronospecies • Speciation • Cline
Modes of speciation:	Allopatric • Peripatric • Parapatric • Sympatric • Polyploidy • Paleopolyploidy
Auxiliary mechanisms:	Sexual selection • Assortative mating • Punctuated equilibrium
Intermediate stages:	Hybrid • Haldane's rule • Ring species

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Sympatry

Information about Sympatry

See also

References