Extinction


The thylacine (Thylacinus cynocephalus) is an example of an extinct species.
Conservation status
Bufo periglenes, the Golden Toad, was last recorded on May 15, 1989
Extinct
Threatened
Lower Risk

Other categories

Related topics

IUCN Red List category abbreviations (version 3.1, 2001)
Comparison of Red List classes above
and NatureServe status below
NatureServe category abbreviations

Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point. Because a species' potential range may be very large, determining this moment is difficult, and is usually done retrospectively. This difficulty leads to phenomena such as Lazarus taxa, where a species presumed extinct abruptly "reappears" (typically in the fossil record) after a period of apparent absence.

More than 99% of all species that ever lived on Earth, amounting to over five billion species,[1] are estimated to have died out.[2][3][4][5] It is estimated that there are currently around 8.7 million species of eukaryote globally,[6] and possibly many times more if microorganisms, like bacteria, are included.[7] Notable extinct animal species include non-avian dinosaurs, saber-toothed cats, dodos, mammoths, ground sloths, thylacines, trilobites, and golden toads.

Through evolution, species arise through the process of speciation—where new varieties of organisms arise and thrive when they are able to find and exploit an ecological niche—and species become extinct when they are no longer able to survive in changing conditions or against superior competition. The relationship between animals and their ecological niches has been firmly established.[8] A typical species becomes extinct within 10 million years of its first appearance,[5] although some species, called living fossils, survive with little to no morphological change for hundreds of millions of years.

Mass extinctions are relatively rare events; however, isolated extinctions of species and clades are quite common, and are a natural part of the evolutionary process.[9] Only recently have extinctions been recorded and scientists have become alarmed at the current high rate of extinctions.[10][11][12][13][14] Most species that become extinct are never scientifically documented. Some scientists estimate that up to half of presently existing plant and animal species may become extinct by 2100.[15] A 2018 report indicated that the phylogenetic diversity of 300 mammalian species erased during the human era since the Late Pleistocene would require 5 to 7 million years to recover.[16]

According to the 2019 Global Assessment Report on Biodiversity and Ecosystem Services by IPBES, the biomass of wild mammals has fallen by 82%, natural ecosystems have lost about half their area and a million species are at risk of extinction—all largely as a result of human actions. Twenty-five percent of plant and animal species are threatened with extinction.[17][18][19] In a subsequent report, IPBES listed unsustainable fishing, hunting and logging as being some of the primary drivers of the global extinction crisis.[20]

In June 2019, one million species of plants and animals were at risk of extinction. At least 571 species have been lost since 1750, but likely many more. The main cause of the extinctions is the destruction of natural habitats by human activities, such as cutting down forests and converting land into fields for farming.[21]

A dagger symbol (†) placed next to the name of a species or other taxon normally indicates its status as extinct.

  1. ^ McKinney, Michael L. (1997). "How do rare species avoid extinction? A paleontological view". In Kunin, W. E.; Gaston, K. J. (eds.). The Biology of Rarity. pp. 110–129. doi:10.1007/978-94-011-5874-9_7. ISBN 978-94-010-6483-5. Archived from the original on 3 February 2023. Retrieved 26 May 2015.
  2. ^ Jablonski, D. (2004). "Extinction: past and present". Nature. 427 (6975): 589. Bibcode:2004Natur.427..589J. doi:10.1038/427589a. PMID 14961099. S2CID 4412106.
  3. ^ Stearns, Beverly Peterson; Stearns, S.C.; Stearns, Stephen C. (2000). Watching, from the Edge of Extinction. Yale University Press. p. preface x. ISBN 978-0-300-08469-6. Archived from the original on 3 February 2023. Retrieved 30 May 2017.
  4. ^ Novacek, Michael J. (8 November 2014). "Prehistory's Brilliant Future". The New York Times. Archived from the original on 29 December 2014. Retrieved 25 December 2014.
  5. ^ a b Newman, Mark (1997). "A model of mass extinction". Journal of Theoretical Biology. 189 (3): 235–252. arXiv:adap-org/9702003. Bibcode:1997JThBi.189..235N. doi:10.1006/jtbi.1997.0508. PMID 9441817. S2CID 9892809.
  6. ^ Mora, Camilo; Tittensor, Derek P.; Adl, Sina; Simpson, Alastair G. B.; Worm, Boris (2011). "How Many Species Are There on Earth and in the Ocean?". PLOS Biology. 9 (8): e1001127. doi:10.1371/journal.pbio.1001127. PMC 3160336. PMID 21886479.
  7. ^ "Researchers find that Earth may be home to 1 trillion species". National Science Foundation. 2 May 2016. Archived from the original on 4 May 2016. Retrieved 6 May 2016.
  8. ^ Sahney, S.; Benton, M.J.; Ferry, P.A. (2010). "Links between global taxonomic diversity, ecological diversity and the expansion of vertebrates on land". Biology Letters. 6 (4): 544–547. doi:10.1098/rsbl.2009.1024. PMC 2936204. PMID 20106856.
  9. ^ Sudakow, Ivan; Myers, Corinne; Petrovskii, Sergei; Sumrall, Colin D.; Witts, James (July 2022). "Knowledge gaps and missing links in understanding mass extinctions: Can mathematical modeling help?". Physics of Life Reviews. 41: 22–57. Bibcode:2022PhLRv..41...22S. doi:10.1016/j.plrev.2022.04.001. PMID 35523056. S2CID 248215038. Archived from the original on 5 November 2022. Retrieved 4 November 2022.
  10. ^ "Species disappearing at an alarming rate, report says". NBC News. 17 November 2004. Archived from the original on 9 February 2022. Retrieved 9 February 2022.
  11. ^ The Sixth Extinction on YouTube (PBS Digital Studios, November 17, 2014)
  12. ^ Ceballos, Gerardo; Ehrlich, Paul R.; Barnosky, Anthony D.; García, Andrés; Pringle, Robert M.; Palmer, Todd M. (2015). "Accelerated modern human–induced species losses: Entering the sixth mass extinction". Science Advances. 1 (5): e1400253. Bibcode:2015SciA....1E0253C. doi:10.1126/sciadv.1400253. PMC 4640606. PMID 26601195.
  13. ^ Ripple WJ, Wolf C, Newsome TM, Galetti M, Alamgir M, Crist E, Mahmoud MI, Laurance WF (13 November 2017). "World Scientists' Warning to Humanity: A Second Notice". BioScience. 67 (12): 1026–1028. doi:10.1093/biosci/bix125. Moreover, we have unleashed a mass extinction event, the sixth in roughly 540 million years, wherein many current life forms could be annihilated or at least committed to extinction by the end of this century.
  14. ^ Cowie, Robert H.; Bouchet, Philippe; Fontaine, Benoît (10 January 2022). "The Sixth Mass Extinction: fact, fiction or speculation?". Biological Reviews. 97 (2): 640–663. doi:10.1111/brv.12816. PMC 9786292. PMID 35014169. S2CID 245889833. Archived from the original on 9 February 2022. Retrieved 9 February 2022.
  15. ^ Wilson, E.O., The Future of Life (2002) (ISBN 0-679-76811-4). See also: Leakey, Richard, The Sixth Extinction : Patterns of Life and the Future of Humankind, ISBN 0-385-46809-1
  16. ^ Davis M, Faurby S, Svenning JC (2018). "Mammal diversity will take millions of years to recover from the current biodiversity crisis". Proc Natl Acad Sci U S A. 115 (44): 11262–11267. Bibcode:2018PNAS..11511262D. doi:10.1073/pnas.1804906115. PMC 6217385. PMID 30322924.
  17. ^ Watts, Jonathan (6 May 2019). "Human society under urgent threat from loss of Earth's natural life". The Guardian. Archived from the original on 14 June 2019. Retrieved 6 May 2019.
  18. ^ Plumer, Brad (6 May 2019). "Humans Are Speeding Extinction and Altering the Natural World at an 'Unprecedented' Pace". The New York Times. Archived from the original on 14 June 2019. Retrieved 6 May 2019.
  19. ^ "Media Release: Nature's Dangerous Decline 'Unprecedented'; Species Extinction Rates 'Accelerating'". Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services. 6 May 2019. Archived from the original on 14 June 2019. Retrieved 6 May 2019.
  20. ^ Briggs, Helen (8 July 2022). "Unsustainable logging, fishing and hunting 'driving extinction'". BBC. Archived from the original on 1 August 2022. Retrieved 2 August 2022.
  21. ^ "'Frightening' number of plant extinctions found in global survey". The Guardian. 10 June 2019. Archived from the original on 22 April 2021. Retrieved 11 June 2019.

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