- Geographical isolation
Geographic isolation, or allopatry, is a term used in the study of
evolution. When part of a population of the same speciesbecomes geographically isolated from the remainder, it may over time evolve characteristics different from the parent population (due to genetic change following geographical isolation, then if the geographical barriers are removed (perhaps due to human activity), members of the two populations will be unable to successfully mate with each other. At this point, a new species has emerged. Geographical isolation is thus a key factor in speciation, the formation of new species - also termed allopatric speciation. The animals would mate and eventually become hybrid species.
However, it is more common for natural selection. This is particularly likely to happen if the isolated population is small, because of
founder effects, or if the population become isolated in an environment which makes new demands upon it. Much research has shown that this is a major reason why there are so many different species throughout the world.
If there is sufficient [genethere to be considerable genetic and phenotypic change without the loss of the capacity for interbreeding - interbreeding is simply prevented by the geographical separation of populations. In this case the populations are normally regarded as
African Elephantfor instance has always been regarded as a single species. Because of morphological and DNAdifferences some scientists classify the elephants into three subspecies. Researchers at the University of California, San Diego(UCSD) have argued that divergence due to geographical isolation has gone further, and the elephants of West Africashould be regarded as a separate species from either the savannaelephants of Central, Eastern and Southern Africa, or the forest elephants of Central Africa.
Other cases arise where two populations that are quite distinct morphologically, and are native to different
continents, have been classified as different species; but when members of one species are introduced into the other's range, they are found to interbreed freely, showing that they were in fact only geographically isolated subspecies. This was found to be the case, for example, when the Mallard"Anas platyrhynchos" was introduced into New Zealand; it interbred freely with the native Grey Duck, which had been classified as a separate species, "Anas superciliosa"; it is controversial whether its specific status can now be retained.
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geographical isolation — geographical isolation. См. географическая изоляция. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) … Молекулярная биология и генетика. Толковый словарь.
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geographical isolation — erdvinė izoliacija statusas T sritis augalininkystė apibrėžtis Izoliacija dėl didelio atstumo ar geografinių kliūčių. atitikmenys: angl. geographical isolation rus. пространственная изоляция … Žemės ūkio augalų selekcijos ir sėklininkystės terminų žodynas
geographical isolation — См. geographic barriers … Dictionary of invertebrate zoology
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isolation — noun (U) 1 the state of being completely separate from any other place, group etc: Because of its geographical isolation, the area developed its own unique culture. 2 a feeling of being lonely and unable to meet or speak to other people:… … Longman dictionary of contemporary English
geographical speciation — speciation occurring during a period of geographical isolation … Dictionary of ichthyology
isolation — noun ADJECTIVE ▪ complete, total ▪ relative ▪ enforced (esp. BrE) ▪ the enforced isolation of life in an Arctic weather station ▪ s … Collocations dictionary
GEOGRAPHICAL SURVEY — Names The name Ereẓ Israel (the Land of Israel) designates the land which, according to the Bible was promised as an inheritance to the Israelite tribes. In the course of time it came to be regarded first by the Jews and then also by the… … Encyclopedia of Judaism
geographical — adj. Geographical is used with these nouns: ↑area, ↑boundary, ↑concentration, ↑context, ↑distance, ↑distribution, ↑diversity, ↑expansion, ↑expression, ↑extent, ↑feature, ↑ … Collocations dictionary