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Information about Refugia

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Proposed Amazonian Refugia and modern distribution of the Selenidera toucanets. From Haffer, 1969
In the most basic biological sense refugia (singular: refugium) are locations of isolated or relict populations of once widespread animal or plant species. This isolation (allopatry) can be due to climatic changes or human activities such as deforestation and over-hunting. Present examples of refuge species are the mountain gorilla, isolated to specific mountains in central Africa, and the Australian Sea Lion, isolated to specific breeding beaches in South Australia due to over hunting. This isolation, in many cases, can be seen as only a temporary state; however, some refugia may be long-standing, thereby having many endemic species, not found elsewhere, which survive as relict populations.

Jürgen Haffer first proposed the concept of refugia to explain the biological diversity of bird populations in the Amazonian river basin. Haffer suggested that climatic change in the late Pleistocene led to reduced reservoirs of habitable forests in which populations become allopatric. Over time, this led to speciation, that is, populations of the same species different refugia evolved differently, creating parapatric sister species. As the Pleistocene ended, the arid conditions gave way to the present humid rainforest environment, reconnecting the refugia.

This mode of speciation has since been expanded and been used to explain population patterns in other areas of the world, such as Africa and North America. Theoretically, current biogeographical patterns can be used to infer past refugia: where several unrelated species follow concurrent range patterns, the area may have been a refugium. But this model of speciation is still highly controversial.

Refugia may also refer to a concentration of human population south of the continental ice sheets during the ice age.

Animal science

Refugia is the proportion of the population that is not selected by drug treatment.

-"In refuge" from drug

It provides a pool of suspectible genes. It dilutes resistant genes in the population. Until recently, overlooked as the most important component of drug resistance selection.

See also

References

  • Coyne, Jerry A. & Orr, H. Allen. 2004. Speciation. Sunderland: Sinauer Associates, Inc. ISBN 0-87893-091-4
  • Haffer, Jurgen. 1969. Speciation in Amazonian Forest Birds. Science. Vol. 165:131-137.
The term relict is used to refer to surviving remnants of natural phenomena. Compare relic which is used to refer to human artifacts or remains.
  • In biology a relict is an organism that at an earlier time was abundant in a large area but now occurs at only one or a few small

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population is the collection of people or organisms of a particular species living in a given geographic area or mortality, and migration, though the field encompasses many dimensions of population change including the family (marriage and divorce), public health, work and the
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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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Deforestation is the conversion of forested areas to non-forest land for use such as arable land, pasture, urban use, logged area, or wasteland.[] Generally, the removal or destruction of significant areas of forest cover has resulted in a degraded environment with
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G. b. berengei

Trinomial name
Gorilla berengei berengei
Matschie, 1914

The Mountain Gorilla (Gorilla beringei beringei[1]) is one of two subspecies of Eastern Gorillas. There are two populations.
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Neophoca
Gray, 1866

Species: N. cinerea

Binomial name
Neophoca cinerea
(Péron, 1816)

The Australian Sea Lion (
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South Australia

Flag Coat of Arms
Slogan or Nickname: Festival State

Other Australian states and territories
Capital Adelaide
Government Constitutional monarchy
Governor Kevin Scarce
Premier Mike Rann (ALP)
Federal representation
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endemic, it is unique to its own place or region; it is found only there, and not found naturally anywhere else. The place must be a discrete geographical unit, often an island or island group, but sometimes a country, habitat type, or other defined area or zone.
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Biodiversity is the variation of life forms within a given ecosystem, biome or for the entire Earth. Biodiversity is often used as a measure of the health of biological systems.
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Pleistocene epoch (IPA: /'plaɪstəsi:n/) on the geologic timescale is the period from 1,808,000 to 11,550 years BP. The Pleistocene epoch had been intended to cover the world's recent period of repeated glaciations.
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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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Parapatric speciation is a form of speciation that occurs due to variations in mating frequency of a population within a continuous geographical area.

In this model, the parent species lives in a continuous habitat, in contrast with allopatric speciation where subpopulations
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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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Africa is the world's second-largest and second most-populous continent, after Asia. At about 30,221,532 km² (11,668,545 sq mi) including adjacent islands, it covers 6% of the Earth's total surface area, and 20.4% of the total land area.
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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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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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An ice sheet is a mass of glacier ice that covers surrounding terrain and is greater than 50,000 km² (19,305 mile²).[1] The only current ice sheets are in Antarctica and Greenland; during the last ice age at Last Glacial Maximum (LGM) the Laurentide ice sheet covered
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ice age is a period of long-term reduction in the temperature of Earth's climate, resulting in an expansion of the continental ice sheets, polar ice sheets and mountain glaciers.
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Biogeography is the study of the distribution of biodiversity over space and time. It aims to reveal where organisms live, at what abundance, and why.[1]
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Population biology is a study of biological populations of organisms, especially in terms of biodiversity, evolution, and environmental biology.

Malthus can almost be considered an early population biologist, even though his training was in economics and the term population
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Population genetics is the study of the allele frequency distribution and change under the influence of the four evolutionary forces: natural selection, genetic drift, mutation and gene flow. It also takes account of population subdivision and population structure in space.
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