Information about Functional Extinction
| Conservation status |
|---|
| the risk of extinction |
| Extinction |
|
Extinct Extinct in the Wild |
| Threatened |
|
Critically Endangered Endangered Vulnerable Threatened |
| Lower risk |
|
Conservation Dependent Near Threatened Least Concern Domesticated |
| See also |
|
World Conservation Union IUCN Red List |
Functional extinction is the extinction of a species or other taxon such that:
- it disappears from the fossil record, or historic reports of its existence cease;[1]
- the reduced population no longer plays a significant role in ecosystem function[2]; or
- the population is no longer viable. There are no individuals able to reproduce, or the small population of breeding individuals will not be able to sustain itself due to inbreeding depression and genetic drift, which leads to a loss of fitness.
In plant populations, self-incompatibility mechanisms may cause related plant specimens to be incompatible, which may lead to functional extinction if an entire population becomes self incompatible. This does not occur in larger populations.
In polygynous populations, where only a few males leave offspring, there is a much smaller reproducing population than if all viable males were considered. Furthermore, the successful males act as a genetic bottleneck, leading to more rapid genetic drift or inbreeding problems in small populations.
Under the IUCN Red List categories, a functionally extinct species that has had no recent sightings may be classified as critically endangered unless there is no reasonable doubt that the last individual has died, such as through extensive surveys. It is extinct in the wild if specimens remain in captivity but there is no reasonable doubt that the last wild specimen has died.Functionally extinct species in modern times
The Abingdon Island Tortoise (Geochelone nigra abingdonii), a subspecies of the Galápagos tortoise, has only one known surviving individual. This individual is named Lonesome George and is estimated to be 70-80 years of age (Galápagos tortoises may live to an age of 120-200 years or more), and is in good health.
The Western Black Rhinoceros (Diceros bicornis longipes) was tentatively declared as extinct by the World Conservation Union in July 2006 [3], after researchers failed to find the animal in its last known habitat. If any animals remain, they would be considered functionally extinct.
The Baiji (Lipotes vexillifer) was a freshwater dolphin found only in the Yangtze River in China. Although efforts were made to conserve the species, the population declined drastically in recent decades. It was declared "functionally extinct" after an expedition in late 2006 failed to find any in the river,[4] the first extinction of a large mammal species in recent decades.See also
References
1. ^ Extinctions in Near Time: Causes, Contexts, and Consequences 1999. Edited by R.D.E. MacPhee, Hans-Dieter Sues. page 202.
2. ^ What is the link between biodiversity and ecosystem services?. ''Scientific Facts on Biodiversity''. Retrieved on 2006-12-16.
3. ^ IUCN 2006. West African black rhino feared extinct. News release of 07 July 2006. The World Conservation Union (IUCN). (Available online)
4. ^ "The Chinese river dolphin is functionally extinct", baiji.org, 2006-12-13.
conservation status of a species is an indicator of the likelihood of that species continuing to survive either in the present day or the future. Many factors are taken into account when assessing the conservation status of a species: not simply the number remaining, but the
..... Click the link for more information.extinction is the cessation of existence of a species or group of taxa, reducing biodiversity. The moment of extinction is generally considered to be the death of the last individual of that species (although the capacity to breed and recover may have been lost before this point).
..... Click the link for more information.Extinct in the Wild (EW) is a conservation status assigned to species or lower taxa, the only living members of which are being kept in captivity or as a naturalized population outside its historic range.
..... Click the link for more information.critically endangered have an extremely high risk of becoming extinct.IUCN Category
The World Conservation Union (IUCN), widely considered to be the most objective and authoritative system for classifying species in terms of the risk of extinction[1]
..... Click the link for more information.endangered species is a population of an organism which is at risk of becoming extinct because it is either few in number, or threatened by changing environmental or predation parameters.
..... Click the link for more information.vulnerable species is a species which is likely to become endangered unless the circumstances threatening its survival and reproduction improve. The following is a very small, non-representative fraction of the 8565 species listed as vulnerable on the IUCN Red List.
..... Click the link for more information.Threatened species are any species (including animals, plants, fungi, insects, bugs, etc.) which are vulnerable to extinction in the near future.
The World Conservation Union (IUCN) is the foremost authority on threatened species, and treats threatened species not as a
..... Click the link for more information.Conservation Dependent (LR/cd) was an IUCN category assigned to species or lower taxa which were dependent on conservation efforts to prevent the taxon becoming threatened with extinction.
..... Click the link for more information.Near Threatened (NT) is a conservation status assigned to species or lower taxa which may be considered threatened with extinction in the near future, although it does not currently qualify for the threatened status.
..... Click the link for more information.Least Concern (LC) is an IUCN category assigned to extant species or lower taxa which have been evaluated but do not qualify for any other category. As such they do not qualify as threatened, nor Near Threatened, nor (prior to 2001) Conservation Dependent.
..... Click the link for more information.Domestication refers to the process whereby a population of animals or plants becomes accustomed to human provision and control. Humans have brought these populations under their care for a wide range of reasons: to produce food or valuable commodities (such as wool, cotton, or
..... Click the link for more information.IUCN
International Organization
Founded October 1948, Fontainebleau, France
Headquarters Rue Mauverney 28, 1196 Gland, Switzerland
Key people Mr Valli Moosa
Ms Julia Marton-Lefèvre
Industry Natural resource conservation
..... Click the link for more information.IUCN Red List of Threatened Species (also known as the IUCN Red List or Red Data List), created in 1963, is the world's most comprehensive inventory of the global conservation status of plant and animal species.
..... Click the link for more information.extinction is the cessation of existence of a species or group of taxa, reducing biodiversity. The moment of extinction is generally considered to be the death of the last individual of that species (although the capacity to breed and recover may have been lost before this point).
..... Click the link for more information.species is one of the basic units of biological classification. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring.
..... Click the link for more information.For the journal, see .A taxon (plural taxa), or taxonomic unit, is a name designating an organism or group of organisms. A taxon is assigned a rank and can be placed at a particular level in a systematic hierarchy reflecting evolutionary
..... Click the link for more information.- For other uses of the term, see Fossil (disambiguation)
FOSSIL is a standard for allowing serial communication for telecommunications programs under the DOS operating system.
..... Click the link for more information.ecosystem is a natural unit consisting of all plants, animals and micro-organisms in an area functioning together with all the non-living physical factors of the environment.
..... Click the link for more information.Inbreeding depression is reduced fitness in a given population as a result of breeding of related individuals. Breeding between closely related individuals, called inbreeding, results in more recessive deleterious traits manifesting themselves.
..... Click the link for more information.In population genetics, genetic drift (or more precisely allelic drift) is the statistical effect that results from the influence that chance has on the survival of alleles (variants of a gene).
..... Click the link for more information.Fitness (often denoted in population genetics models) is a central concept in evolutionary theory. It describes the capability of an individual of certain genotype to reproduce, and usually is equal to the proportion of the individual's genes in all the genes of the next generation.
..... Click the link for more information.Self-incompatibility (SI) is a general name for several genetic mechanisms in angiosperms, which prevent self-fertilization and thus encourage outcrossing. In plants with SI, when a pollen grain produced in a plant reaches a stigma of the same plant or another plant with a
..... Click the link for more information.The term polygyny (neo-Greek: poly+gune Many + Wives) is used in related ways in social anthropology and sociobiology.
In social anthropology polygyny refers to the practice of having more than one wife at the same time.
..... Click the link for more information.IUCN Red List of Threatened Species (also known as the IUCN Red List or Red Data List), created in 1963, is the world's most comprehensive inventory of the global conservation status of plant and animal species.
..... Click the link for more information.critically endangered have an extremely high risk of becoming extinct.IUCN Category
The World Conservation Union (IUCN), widely considered to be the most objective and authoritative system for classifying species in terms of the risk of extinction[1]
..... Click the link for more information.G. nigra
Binomial name
Geochelone nigra
(Quoy & Gaimard, 1824)
SynonymsGeochelone elephantopus (Harlan, 1827) The Galápagos tortoise (or
..... Click the link for more information.G. n. abingdoni
Trinomial name
Geochelone nigra abingdoni
(Günther, 1877)
Lonesome George is the name given to the last known individual of the Pinta Island Tortoise, subspecies Geochelone nigra abingdonii
..... Click the link for more information.D. b. longipes
Trinomial name
Diceros bicornis longipes
Zukowsky, 1949
The Western Black Rhinoceros (Diceros bicornis longipes) or West African Black Rhinoceros
..... Click the link for more information.Lipotidae
Genus: Lipotes
Species: L. vexillifer
Binomial name
Lipotes vexillifer
Miller, 1918
..... Click the link for more information.Platanistoidea
Families
See text
River dolphins are four living species of dolphin which reside in freshwater rivers and estuaries. They are classed in the Platanistoidea superfamily of cetaceans. Three species live in fresh water rivers.
..... Click the link for more information.
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