Karewar kwayoyin halitta

Kashewa shine ƙarewar kwayoyin halitta ta mutuwar membanta na ƙarshe. Taxon na iya zama bacewa ta hanyar aiki kafin mutuwar membansa na ƙarshe idan ya rasa ikon haifuwa da murmurewa. Kamar yadda yuwuwar kewayon nau'ikan na iya zama babba, tantance wannan lokacin yana da wahala, kuma yawanci ana yin ta ne a baya. Wannan wahalar tana haifar da al'amura kamar Li'azaru taxa, inda wani nau'in da ake zaton ya bace ba zato ba tsammani "ya sake bayyana" (yawanci a tarihin burbushin halittu) bayan wani lokaci na bayyanar.

Sama da nau'in biliyan biyarMcKinney, 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. an kiyasta sun mutu.Jablonski, D. (2004). "Extinction: past and present". Nature. 427 (6975): 589. Bibcode:2004Natur.427..589J. doi:10.1038/427589a. PMID 14961099. S2CID 4412106.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 2017Novacek, 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.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.An kiyasta cewa a halin yanzu akwai nau'ikan eukaryotes kusan miliyan 8.7 a duniya,[6] yiwuwa sau da yawa idan an haɗa  ƙananan ƙwayoyin cuta.[7]Fitattun nau'ikan dabbobin da suka bace sun haɗa da dinosaurs waɗanda ba na aviya ba, kuliyoyi masu haƙori, da mammoths. Ta hanyar juyin halitta, nau'in halitta suna tasowa ta hanyar tantancewa. Irin nau'ikan suna ɓacewa lokacin da ba za su iya rayuwa a cikin yanayi masu canzawa ba ko kuma a kan gasa mafi girma. Dangantakar da ke tsakanin dabbobi da mahallinsu ta kafu sosai.[8]Wani nau'in nau'in nau'in nau'in nau'in nau'in nau'in nau'in nau'in nau'in nau'in nau'in nau'in nau'in nau'in nau'in nau'in nau'in nau'in nau'in nau'in nau'in nau'in nau'in nau'in nau'in nau'in nau'in nau'in nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i)) yana ɓacewa a cikin shekaru miliyan 10 na farkon bayyanarsa, ko da yake wasu nau'in, da ake kira burbushin halittu, suna rayuwa ba tare da wani canji na halitta ba har tsawon daruruwan miliyoyin shekaru.

 Bayyani 
Tsarin waje na Entencter Leidendron daga Carboniferous na Ohio Kenrick, Paul; Davis, Paul (2004). Fossil Plants. Smithsonian Books. ISBN 978-0-565-09176-7. [23]

Jinsin yana ƙarewa lokacin da memba na ƙarshe suka mutu. Haske saboda haka ya zama yaƙini yayin da babu wani mutane da suka tsira wanda zai iya haifar da sabon ƙarni. Wata jinsi na iya zama da aiki sosai lokacin da mutane mutane ne kawai suka tsira saboda rashin lafiya, shekaru, rashin daidaituwa na mata), ko wasu dalilai.

Pinpointing hakkin (ko Pseudoextarction) na jinsin yana buƙatar bayyananniyar ma'anar wancan nau'in. Idan za a ayyana abin da aka yanke, jinsin da ke cikin tambaya dole ne ya zama rarrabe dabam daga kowane magabata ko jinsin 'yar da kuma daga kowane nau'in da ya shafi. Hallaka jinsuna (ko sauyawa daga wani 'y' ya saƙa) yana taka muhimmiyar rawa a cikin yanayin daidaitaccen daidaitaccen misalin Stephen Jay Gould da Niles Tiledge. See: Niles Eldredge, Time Frames: Rethinking of Darwinian Evolution and the Theory of Punctuated Equilibria, 1986, Heinemann ISBN 0-434-22610-6

Pseudoextinction

Babban labarin: Pseudoextinction

Kashe nau'in iyaye inda nau'in 'ya'ya mata ko nau'o'in nau'o'in suna wanzu ana kiran su pseudoextinction ko phyletic extinction. Yadda ya kamata, tsohon harajin ya ɓace, ya canza (anagenesis) zuwa magaji, ""Discovery" of the Coelacanth". Archived from the original on 21 January 2013. Retrieved 2 March 2013. ko ya rabu zuwa fiye da ɗaya (cladogenesis).Freiwald, André; Lavaleye, Marc; Heugten, Bart Van; Beuck, Lydia; Hoffman, Leon (4 June 2019). "Last snails standing since the Early Pleistocene, a tale of Calliostomatidae (Gastropoda) living in deep-water coral habitats in the north-eastern Atlantic". Zootaxa. 4613 (1): 93–110. doi:10.11646/zootaxa.4613.1.4. ISSN 1175-5334. PMID 31716426..

Pseudoextinction yana da wuyar nunawa sai dai idan mutum yana da sarkar shaida mai ƙarfi da ke haɗa nau'in rayayyun halittu da mambobi na jinsin da suka rigaya. Misali, a wani lokaci ana da’awar cewa bacewar Hyracotherium, wanda doki ne na farko da ya yi tarayya da kakanni daya da dokin zamani, ba ya gushewa, maimakon bacewa, domin akwai nau’in Equus da dama da suka hada da zebra da jaki; duk da haka, kamar yadda nau'in burbushin halittu yawanci ba su bar wani abu na kwayoyin halitta a baya ba, ba za a iya cewa ko Hyracotherium ya samo asali ne daga nau'in doki na zamani ko kuma ya samo asali ne daga kakanni guda tare da dawakai na zamani. Pseudoextinction ya fi sauƙi don nunawa ga manyan ƙungiyoyin haraji.

Li'azaru taxa

Babban labarin: Li'azaru taxon

Wani nau'in Li'azaru ko nau'in Li'azaru yana nufin lokuttan da ake tunanin wani nau'i ko harajin zai ƙare, amma an sake gano shi. Hakanan yana iya komawa ga al'amuran da manyan gibi a cikin tarihin burbushin burbushin sakamakon harajin da burbushin ya sake bayyana da yawa daga baya, kodayake taxon na iya zama bacewa a wani lokaci.

Coelacanth, kifin da ke da alaƙa da lungfish da tetrapods, misali ne na harajin Li'azaru wanda aka sani kawai daga bayanan burbushin halittu kuma ana ɗaukarsa ya ɓace tun ƙarshen lokacin Cretaceous. A cikin 1938, duk da haka, an sami samfurin rayuwa a bakin kogin Chalumna (yanzu Tyolomnqa) a gabar gabashin Afirka ta Kudu.[31] Calliostoma bulatum, wani nau'in katantan ruwan teku mai zurfi da aka kwatanta asali daga burbushin halittu a 1844 ya tabbatar da cewa nau'in Li'azaru ne lokacin da aka kwatanta wasu mutane a cikin 2019.

 Manazarta