Editing Pleistocene (section)

==Fauna==
{{See also|Quaternary extinction event}}
Both marine and continental faunas were essentially modern but with many more large land mammals such as [[Mammoth]]s, [[Mastodon]]s, ''[[Diprotodon]]s'', ''[[Smilodon]]s'', [[tiger]]s, [[lion]]s, [[Aurochs]], [[Arctodus|short-faced]] [[Arctotherium|bears]], [[giant sloth]]s, species within ''[[Gigantopithecus]]'' and others. Isolated landmasses such as [[Australia]], [[Madagascar]], [[New Zealand]] and islands in the Pacific saw the evolution of large birds and even reptiles such as the [[Elephant bird]], [[moa]], [[Haast's eagle]], ''[[Quinkana]]'', ''[[Megalania]]'' and ''[[Meiolania]]''.

The severe climatic changes during the Ice Age had major impacts on the fauna and flora. With each advance of the ice, large areas of the continents became depopulated, and plants and animals retreating southwards in front of the advancing glacier faced tremendous stress. The most severe stress resulted from drastic climatic changes, reduced living space, and curtailed food supply. A major [[extinction event]] of large [[mammal]]s ([[megafauna]]), which included [[mammoth]]s, [[mastodon]]s, [[Machairodontinae|saber-toothed cats]], ''[[glyptodon]]s'', the [[woolly rhinoceros]], various [[giraffid]]s, such as the [[Sivatherium]]; [[ground sloth]]s, [[Irish elk]], [[Panthera spelaea|cave lions]], [[cave bear]]s, [[Gomphothere]]s, [[American lion]]s, [[dire wolves]], and [[Arctodus|short-faced bears]], began late in the Pleistocene and continued into the Holocene. [[Neanderthal]]s also became extinct during this period. At the end of the last ice age, [[Poikilotherm|cold-blooded]] animals, smaller mammals like [[wood mouse|wood mice]], migratory birds, and swifter animals like [[whitetail deer]] had replaced the megafauna and migrated north. Late Pleistocene [[bighorn sheep]] were more slender and had longer legs than their descendants today. Scientists believe that the change in predator fauna after the late Pleistocene extinctions resulted in a change of body shape as the species adapted for increased power rather than speed.<ref>{{cite book |last1=Valdez |first1=Raul |title=Mountain Sheep of North America}}</ref>

The extinctions hardly affected Africa but were especially severe in [[North America]] where native [[horse]]s and [[camel]]s were wiped out.

[[File:Pleistocene Chart.jpg|thumb|upright=1.5|Various schemes for subdividing the Pleistocene]]

* [[Asian land mammal ages]] (ALMA) include [[Zhoukoudianian]], [[Nihewanian]], and [[Yushean]].
* [[European land mammal ages]] (ELMA) include the [[Villafranchian]], [[Galerian Mammal Age|Galerian]], and [[Aurelian Mammal Age|Aurelian]]
*[[North American land mammal ages]] (NALMA) include [[Blancan]] (4.75–1.8), [[Irvingtonian]] (1.8–0.24) and [[Rancholabrean]] (0.24–0.01) in millions of years. The Blancan extends significantly back into the Pliocene.
* [[South American land mammal ages]] (SALMA) include [[Uquian]] (2.5–1.5), [[Ensenadan]] (1.5–0.3) and [[Lujanian]] (0.3–0.01) in millions of years. The Uquian previously extended significantly back into the Pliocene, although the new definition places it entirely within the Pleistocene.

In July 2018, a team of [[Russians|Russian]] scientists in collaboration with [[Princeton University]] announced that they had brought two female [[nematodes]] frozen in [[permafrost]], from around 42,000 years ago, back to life. The two nematodes, at the time, were the oldest confirmed living animals on the planet.<ref>{{cite web |url=http://siberiantimes.com/science/casestudy/news/worms-frozen-in-permafrost-for-up-to-42000-years-come-back-to-life |title=Worms frozen in permafrost for up to 42,000 years come back to life |work=The Siberian Times |date=26 July 2018 |access-date=25 August 2021}}</ref><ref>{{cite journal |last1=Shatilovich |first1=A. V. |last2=Tchesunov |first2=A. V. |last3=Neretina |first3=T. V. |last4=Grabarnik |first4=I. P. |last5=Gubin |first5=S. V. |last6=Vishnivetskaya |first6=T. A. |last7=Onstott |first7=T. C. |last8=Rivkina |first8=E. M. |title=Viable Nematodes from Late Pleistocene Permafrost of the Kolyma River Lowland |journal=Doklady Biological Sciences |date=16 July 2018 |volume=480 |issue=1 |pages=100–102 |doi=10.1134/S0012496618030079 |pmid=30009350 |s2cid=49743808 }}</ref>

<gallery widths="200px" heights="150px">
File:Ice age fauna of northern Spain - Mauricio Antón.jpg|Pleistocene of [[Northern Spain]], including [[woolly mammoth]], [[Panthera leo fossilis|cave lion]]s eating a [[reindeer]], [[Equus ferus|horses]], and [[woolly rhinoceros]]
File:Pleistocene SA.jpg|Pleistocene of [[South America]], including ''[[Megatherium]]'' and two ''[[Glyptodon]]''
</gallery>

===Humans===
{{Main|Human evolution|Paleolithic|Settlement of the Americas}}

The [[human evolution|evolution]] of [[anatomically modern humans]] took place during the Pleistocene.<ref>{{cite journal | last1 = Rogers | first1 = A.R. | last2 = Jorde | first2 = L.B. | year = 1995 | title = Genetic evidence on modern human origins | journal = Human Biology | volume = 67 | issue = 1| pages = 1–36 |jstor=41465052 | pmid = 7721272 }}</ref><ref>{{cite journal | last1 = Wall | first1 = J.D. | last2 = Przeworski | first2 = M. | year = 2000 | title = When did the human population start increasing? | pmc =1461207 |pmid=10924481 | journal = [[Genetics (journal)|Genetics]] | volume = 155 | issue = 4| pages = 1865–1874 | doi = 10.1093/genetics/155.4.1865 }}</ref> At the beginning of the Pleistocene ''[[Paranthropus]]'' species were still present, as well as early human ancestors, but during the lower Palaeolithic they disappeared, and the only [[hominin]] species found in fossilic records is ''[[Homo erectus]]'' for much of the Pleistocene. [[Acheulean]] [[Lithic analysis|lithics]] appear along with ''Homo erectus'', some 1.8&nbsp;million years ago, replacing the more primitive [[Oldowan]] industry used by ''[[Australopithecus garhi]]'' and by the earliest species of ''Homo''. The [[Middle Paleolithic]] saw more varied speciation within ''Homo'', including the appearance of ''[[Homo sapiens]]'' about 300,000 years ago.<ref>{{cite journal |last1=Hublin |first1=Jean-Jacques |last2=Ben-Ncer |first2=Abdelouahed |last3=Bailey |first3=Shara E. |last4=Freidline |first4=Sarah E. |last5=Neubauer |first5=Simon |last6=Skinner |first6=Matthew M. |last7=Bergmann |first7=Inga |last8=Le Cabec |first8=Adeline |last9=Benazzi |first9=Stefano |last10=Harvati |first10=Katerina |last11=Gunz |first11=Philipp |title=New fossils from Jebel Irhoud, Morocco and the pan-African origin of Homo sapiens |journal=Nature |date=8 June 2017 |volume=546 |issue=7657 |pages=289–292 |doi=10.1038/nature22336|pmid=28593953 |bibcode=2017Natur.546..289H |s2cid=256771372 |url=https://kar.kent.ac.uk/62267/1/Submission_288356_1_art_file_2637492_j96j1b.pdf }}</ref> Artifacts associated with [[Behavioral modernity|modern human behavior]] are unambiguously attested starting 40,000–50,000 years ago.<ref name="Klein 1995">{{cite journal |last= Klein |first= Richard |title= Anatomy, behavior, and modern human origins |journal= Journal of World Prehistory |date= 1995 |volume= 9 |issue= 2 |pages= 167–198 |doi= 10.1007/bf02221838|s2cid= 10402296 }}</ref>

According to mitochondrial timing techniques, [[anatomically modern humans|modern humans]] migrated from Africa after the [[Riss glaciation]] in the Middle Palaeolithic during the [[Eemian Stage]], spreading all over the ice-free world during the late Pleistocene.<ref>{{cite journal | last1 = Cann | first1 = R.L. | last2 = Stoneking | first2 = M. | last3 = Wilson | first3 = A.C. | date = 1 January 1987 | title = Mitochondrial DNA and human evolution | journal = Nature | volume = 325 | issue = 6099 | pages = 31–36 | doi=10.1038/325031a0 | pmid=3025745| bibcode = 1987Natur.325...31C | s2cid = 4285418 }}</ref><ref>Stringer, C.B. (1992) "Evolution of early modern humans" ''In'': Jones, Steve; Martin, R. and Pilbeam, David R. (eds.) (1992) ''The Cambridge encyclopedia of human evolution'' Cambridge University Press, Cambridge, {{ISBN|0-521-32370-3}}, pp. 241–251.</ref><ref>{{cite journal |author=Templeton, A. R. |date=7 March 2002 |url=http://www.bioguider.com/ebook/biology/pdf/Templeton_n2002.pdf |title=Out of Africa again and again |journal=[[Nature (journal)|Nature]] |volume=416 |pages=45–51 |doi=10.1038/416045a |pmid=11882887 |issue=6876 |bibcode=2002Natur.416...45T |s2cid=4397398 |access-date=17 November 2017 |archive-date=12 April 2020 |archive-url=https://web.archive.org/web/20200412024836/http://www.bioguider.com/ebook/biology/pdf/Templeton_n2002.pdf  }}</ref> A 2005 study posits that humans in this migration interbred with [[archaic human]] forms already outside of Africa by the late Pleistocene, incorporating archaic human genetic material into the modern human gene pool.<ref>{{cite journal | last1 = Eswarana | first1 = Vinayak | last2 = Harpendingb | first2 = Henry | last3 = Rogers | first3 = Alan R | date = July 2005 | title = Genomics refutes an exclusively African origin of humans | doi = 10.1016/j.jhevol.2005.02.006 | journal = Journal of Human Evolution | volume = 49 | issue = 1| pages = 1–18 | pmid=15878780| bibcode = 2005JHumE..49....1E }}</ref>

{{Hominin species during Pleistocene}}