Editing Human evolution (section)

== Evolution of genus ''Homo'' ==
{{Main|Homo}}
{{Human timeline}}
The earliest documented representative of the genus ''Homo'' is ''[[Homo habilis]]'', which evolved around {{Mya|2.8}},<ref name="autogenerated1">{{cite news |last=Ghosh |first=Pallab |author-link=Pallab Ghosh |date=March 4, 2015 |title='First human' discovered in Ethiopia |url= https://www.bbc.com/news/science-environment-31718336 |work=BBC News |location=London |access-date=April 19, 2015 |archive-date=April 18, 2015 |archive-url= https://web.archive.org/web/20150418032919/http://www.bbc.com/news/science-environment-31718336 |url-status=live}}</ref> and is arguably the earliest species for which there is positive evidence of the use of stone tools. The brains of these early hominins were about the same size as that of a chimpanzee, although it has been suggested that this was the time in which the human [[SRGAP2]] [[gene]] doubled, producing a more rapid wiring of the frontal cortex. During the next million years a process of rapid [[encephalization]] occurred, and with the arrival of ''[[Homo erectus]]'' and ''[[Homo ergaster]]'' in the [[fossil#Dating|fossil record]], cranial capacity had doubled to 850&nbsp;cm<sup>3</sup>.{{sfn|Swisher|Curtis|Lewin|2001}} (Such an increase in human brain size is equivalent to each generation having 125,000 more [[neuron]]s than their parents.) It is believed that ''H.&nbsp;erectus'' and ''H.&nbsp;ergaster'' were the first to use fire and complex tools, and were the first of the hominin line to leave Africa, spreading throughout Africa, Asia, and Europe between {{Mya|1.3|1.8}}.
According to the recent African origin theory, modern humans evolved in Africa possibly from ''[[H.&nbsp;heidelbergensis]]'', ''[[H.&nbsp;rhodesiensis]]'' or ''[[H.&nbsp;antecessor]]'' and migrated out of the continent some 50,000 to 100,000 years ago, gradually replacing local populations of ''H.&nbsp;erectus'', [[Denisova hominin]]s, ''[[H.&nbsp;floresiensis]]'', ''[[H.&nbsp;luzonensis]]'' and ''[[H.&nbsp;neanderthalensis]]'', whose ancestors had left Africa in earlier migrations.{{sfn|Stringer|1994|p=242}}{{sfn|McHenry|2009|p=265}}<ref>{{cite journal |title=Out of Africa Revisited |date=May 13, 2005 |journal=[[Science (journal)|Science]] |type=This Week in ''Science'' |volume=308 |issue=5724 |page=921 |doi=10.1126/science.2005.308.5724.twis |doi-access=free |s2cid=220100436 |issn=0036-8075}}</ref><ref>{{cite journal |last=Stringer |first=Chris |author-link=Chris Stringer |date=June 12, 2003 |title=Human evolution: Out of Ethiopia |journal=[[Nature (journal)|Nature]] |volume=423 |issue=6941 |pages=692–695 |doi=10.1038/423692a |issn=0028-0836 |pmid=12802315 |bibcode=2003Natur.423..692S |s2cid=26693109}}</ref><ref>{{cite web |url= http://www.actionbioscience.org/evolution/johanson.html |title=Origins of Modern Humans: Multiregional or Out of Africa? |last=Johanson |first=Donald |author-link=Donald Johanson |date=May 2001 |website=[[actionbioscience]] |publisher=[[American Institute of Biological Sciences]] |location=Washington, DC |access-date=November 23, 2009 |archive-date=November 14, 2010 |archive-url= https://web.archive.org/web/20101114081543/http://www.actionbioscience.org/evolution/johanson.html}}</ref> [[Archaic humans|Archaic ''Homo sapiens'']], the forerunner of [[anatomically modern humans]], evolved in the [[Middle Paleolithic]] between 400,000 and 250,000 years ago.<ref>{{cite press release |last1=Mixon |first1=Bobbie |last2=Ehardt |first2=Carolyn |last3=Hammer |first3=Michael |date=September 6, 2011 |title=Evolution's Past Is Modern Human's Present |url= https://www.nsf.gov/news/news_summ.jsp?org=NSF&cntn_id=121603&preview=false |publisher=[[National Science Foundation]] |id=Press Release 11-181 |access-date=April 20, 2015 |archive-date=December 17, 2014 |archive-url= https://web.archive.org/web/20141217084326/http://www.nsf.gov/news/news_summ.jsp?org=NSF&cntn_id=121603&preview=false |url-status=live}}</ref><ref>{{cite web |url= http://anthro.palomar.edu/homo2/mod_homo_4.htm |title=Early Modern ''Homo sapiens'' |last=O'Neil |first=Dennis |website=Evolution of Modern Humans: A Survey of the Biological and Cultural Evolution of Archaic and Modern Homo sapiens |publisher=[[Palomar College]] |location=San Marcos, California |type=Tutorial |access-date=April 20, 2015 |archive-date=April 30, 2015 |archive-url= https://web.archive.org/web/20150430142627/http://anthro.palomar.edu/homo2/mod_homo_4.htm}}</ref><ref>{{cite journal |title=Fossil Reanalysis Pushes Back Origin of ''Homo sapiens'' |url= http://www.scientificamerican.com/article/fossil-reanalysis-pushes/ |date=February 17, 2005 |journal=[[Scientific American]] |issn=0036-8733 |access-date=April 20, 2015 |archive-date=January 15, 2016 |archive-url= https://web.archive.org/web/20160115000603/http://www.scientificamerican.com/article/fossil-reanalysis-pushes/ |url-status=live}}</ref> Recent [[DNA]] evidence suggests that several [[haplotype]]s of [[Neanderthal]] origin are present among all non-African populations, and Neanderthals and other hominins, such as Denisovans, may have contributed up to 6% of their [[genome]] to present-day humans, suggestive of a [[Interbreeding between archaic and modern humans|limited interbreeding between these species]].<ref name="pmid21179161">{{cite journal |last1=Reich |first1=David |author1-link=David Reich (geneticist) |last2=Green |first2=Richard E. |last3=Kircher |first3=Martin |last4=Krause |first4=Johannes |last5=Patterson |first5=Nick |last6=Durand |first6=Eric Y. |last7=Viola |first7=Bence |last8=Briggs |first8=Adrian W. |last9=Stenzel |first9=Udo |last10=Johnson |first10=Philip L. F. |last11=Maricic |first11=Tomislav |last12=Good |first12=Jeffrey M. |last13=Marques-Bonet |first13=Tomas |last14=Alkan |first14=Can |last15=Fu |first15=Qiaomei |last16=Mallick |first16=Swapan |last17=Li |first17=Heng |last18=Meyer |first18=Matthias |last19=Eichler |first19=Evan E. |last20=Stoneking |first20=Mark |last21=Richards |first21=Michael |last22=Talamo |first22=Sahra |last23=Shunkov |first23=Michael V. |last24=Derevianko |first24=Anatoli P. |last25=Hublin |first25=Jean-Jacques |last26=Kelso |first26=Janet |last27=Slatkin |first27=Montgomery |last28=Pääbo |first28=Svante |author28-link=Svante Pääbo |display-authors=3 |date=December 23, 2010 |title=Genetic history of an archaic hominin group from Denisova Cave in Siberia |journal=[[Nature (journal)|Nature]] |volume=468 |issue=7327 |pages=1053–1060 |bibcode=2010Natur.468.1053R |doi=10.1038/nature09710 |issn=0028-0836 |pmid=21179161 |pmc=4306417 |hdl=10230/25596}}</ref><ref name="pmid20439435">{{cite journal |last=Noonan |first=James P. |date=May 2010 |title=Neanderthal genomics and the evolution of modern humans |journal=[[Genome Research]] |volume=20 |issue=5 |pages=547–553 |doi=10.1101/gr.076000.108 |issn=1088-9051 |pmc=2860157 |pmid=20439435}}</ref><ref name="10.1126/science.1209202">{{cite journal |last1=Abi-Rached |first1=Laurent |last2=Jobin |first2=Matthew J. |last3=Kulkarni |first3=Subhash |last4=McWhinnie |first4=A. |last5=Dalva |first5=K. |last6=Gragert |first6=L. |last7=Babrzadeh |first7=F. |last8=Gharizadeh |first8=B. |last9=Luo |first9=M. |last10=Plummer |first10=F. A. |last11=Kimani |first11=J. |last12=Carrington |first12=M. |last13=Middleton |first13=D. |last14=Rajalingam |first14=R. |last15=Beksac |first15=M. |last16=Marsh |first16=S. G. E. |last17=Maiers |first17=M. |last18=Guethlein |first18=L. A. |last19=Tavoularis |first19=S. |last20=Little |first20=A.-M. |last21=Green |first21=R. E. |last22=Norman |first22=P. J. |last23=Parham |first23=P. |display-authors=3 |date=October 7, 2011 |title=The Shaping of Modern Human Immune Systems by Multiregional Admixture with Archaic Humans |journal=[[Science (journal)|Science]] |volume=334 |issue=6052 |pages=89–94 |bibcode=2011Sci...334...89A |doi=10.1126/science.1209202 |issn=0036-8075 |pmc=3677943 |pmid=21868630}}</ref> According to some anthropologists, the transition to [[behavioral modernity]] with the development of symbolic culture, language, and specialized [[lithic technology]] happened around 50,000 years ago (beginning of the [[Upper Paleolithic]]),<ref>{{cite journal |last=Mellars |author-link=Paul Mellars |first=Paul |date=June 20, 2006 |title=Why did modern human populations disperse from Africa ca. 60,000 years ago? A new model |journal=[[Proceedings of the National Academy of Sciences of the United States of America]] |volume=103 |issue=25 |pages=9381–9386 |bibcode=2006PNAS..103.9381M |doi=10.1073/pnas.0510792103 |issn=0027-8424 |pmc=1480416 |pmid=16772383 |doi-access=free}}</ref> although others point to evidence of a gradual change over a longer time span during the Middle Paleolithic.<ref name="Mcbrearty_Brooks">{{cite journal |last1=McBrearty |first1=Sally |last2=Brooks |first2=Alison S. |date=November 2000 |title=The revolution that wasn't: A new interpretation of the origin of modern human behavior |journal=[[Journal of Human Evolution]] |volume=39 |issue=5 |pages=453–563 |doi=10.1006/jhev.2000.0435 |issn=0047-2484 |pmid=11102266 |bibcode=2000JHumE..39..453M |s2cid=42968840}}</ref>[[File:Homo-Stammbaum, Version Stringer-en.svg|thumb|left|upright=1.35|A model of the phylogeny of ''H. sapiens'' during the [[Middle Paleolithic]]. The horizontal axis represents geographic location; the vertical axis represents time in [[Year#Abbreviations yr and ya|millions of years ago]] (Mya).<ref>based on
{{cite journal |doi=10.1126/science.aao6266 |pmid=28971970 |volume=358 |title=Southern African ancient genomes estimate modern human divergence to 350,000 to 260,000 years ago |date=2017 |journal=[[Science (journal)|Science]] |pages=652–655 |last1=Schlebusch |first1=C. M. |last2=Malmström |first2=H. |last3=Günther |first3=T. |last4=Sjödin |first4=P. |last5=Coutinho |first5=A. |last6=Edlund |first6=H. |last7=Munters |first7=A. R. |last8=Vicente |first8=M. |last9=Steyn |first9=M. |last10=Soodyall |first10=H. |last11=Lombard |first11=M. |last12=Jakobsson |first12=M. |issue=6363 |bibcode=2017Sci...358..652S |s2cid=206663925 |doi-access=free}}, [https://d2ufo47lrtsv5s.cloudfront.net/content/sci/early/2017/09/27/science.aao6266/F3.large.jpg Fig. 3] {{Webarchive|url= https://web.archive.org/web/20180114130711/https://d2ufo47lrtsv5s.cloudfront.net/content/sci/early/2017/09/27/science.aao6266/F3.large.jpg |date=January 14, 2018}} (''H.&nbsp;sapiens'' divergence times) and
{{cite journal |last=Stringer |first=C. |title=What makes a modern human |journal=[[Nature (journal)|Nature]] |date=2012 |volume=485 |issue=7396 |pages=33–35 |doi=10.1038/485033a |pmid=22552077 |bibcode=2012Natur.485...33S |s2cid=4420496 |doi-access=free}} (archaic admixture).</ref>
''Homo Erectus'' is shown spreading across Eurasia starting around 1.8 Mya. ''Homo heidelbergensis'' is shown diverging into Neanderthals, Denisovans and ''H.&nbsp;sapiens''. With the expansion of ''H.&nbsp;sapiens'' after 0.2 Mya, Neanderthals, Denisovans and unspecified archaic African hominins are shown as [[Interbreeding between archaic and modern humans|again subsumed]] into the ''H.&nbsp;sapiens'' lineage. Admixture events in modern African populations are also indicated.]]

''Homo sapiens'' is the only [[extant species]] of its genus, ''Homo''. While some (extinct) ''Homo'' species might have been ancestors of ''Homo sapiens'', many, perhaps most, were likely "cousins", having [[speciate]]d away from the ancestral hominin line.<ref>{{cite journal |last1=Strait |first1=David S. |last2=Grine |first2=Frederick E. |author2-link=Frederick E. Grine |last3=Moniz |first3=Marc A. |date=January 1997 |title=A reappraisal of early hominid phylogeny |journal=Journal of Human Evolution |volume=32 |issue=1 |pages=17–82 |doi=10.1006/jhev.1996.0097 |issn=0047-2484 |pmid=9034954 |bibcode=1997JHumE..32...17S |s2cid=37754799}}</ref>{{sfn|Bryson|2004|pp=522–543}} There is yet no consensus as to which of these groups should be considered a separate species and which should be subspecies; this may be due to the dearth of fossils or to the slight differences used to classify species in the genus ''Homo''.{{sfn|Bryson|2004|pp=522–543}} The [[Sahara pump theory]] (describing an occasionally passable [[Wet Sahara|"wet" Sahara]] desert) provides one possible explanation of the intermittent migration and speciation in the genus ''Homo''.

Based on archaeological and paleontological evidence, it has been possible to infer, to some extent, the ancient dietary practices<ref name="NYT-20150813" /> of various ''Homo'' species and to study the role of diet in physical and behavioral evolution within ''Homo''.<ref name="Leonard_2007" />{{sfn|Walker|2007|pp=[https://books.google.com/books?id=6mxZ1hNBHgkC&pg=PA3 3–10]}}{{sfn|Ungar|Teaford|2002}}{{sfn|Bogin|1997|pp=[https://web.archive.org/web/20031203003838/http://citd.scar.utoronto.ca/ANTAO1/Projects/Bogin.html 96–142]}}<ref>{{cite journal |last=Barnicot |first=Nigel A. |date=April–June 2005 |title=Human nutrition: Evolutionary perspectives |journal=Integrative Physiological & Behavioral Science |volume=40 |issue=2 |pages=114–117 |doi=10.1007/BF02734246 |issn=1932-4502 |pmid=17393680 |s2cid=39549910}}</ref>

Some anthropologists and archaeologists subscribe to the [[Toba catastrophe theory]], which posits that the [[supereruption]] of [[Lake Toba]] on Sumatra in Indonesia some 70,000 years ago caused global starvation,<ref>{{cite news |title=The new batch – 150,000 years ago |url= http://www.bbc.co.uk/sn/prehistoric_life/human/human_evolution/new_batch1.shtml |work=The evolution of man |location=London |publisher=BBC Science & Nature |archive-url= https://web.archive.org/web/20060118155703/http://www.bbc.co.uk/sn/prehistoric_life/human/human_evolution/new_batch1.shtml |archive-date=January 18, 2006 |access-date=April 28, 2015}}</ref> killing the majority of humans and creating a [[population bottleneck]] that affected the genetic inheritance of all humans today.<ref>{{cite news |last=Whitehouse |first=David |date=June 9, 2003 |title=When humans faced extinction |url= http://news.bbc.co.uk/2/hi/science/nature/2975862.stm |work=BBC News |location=London |publisher=BBC |access-date=January 5, 2007 |archive-date=September 4, 2010 |archive-url= https://web.archive.org/web/20100904071921/http://news.bbc.co.uk/2/hi/science/nature/2975862.stm |url-status=live}}</ref> The genetic and archaeological evidence for this remains in question however.<ref>{{Cite web |url= https://www.sciencedaily.com/releases/2018/03/180312132956.htm |title=Modern humans flourished through ancient supervolcano eruption 74,000 years ago: Modern humans flourished through ancient supervolcano eruption |website=ScienceDaily |access-date=January 24, 2019 |archive-date=January 24, 2019 |archive-url= https://web.archive.org/web/20190124152235/https://www.sciencedaily.com/releases/2018/03/180312132956.htm |url-status=live}}</ref> A 2023 genetic study suggests that a similar human [[population bottleneck]] of between 1,000 and 100,000 survivors occurred "around 930,000 and 813,000 years ago ... lasted for about 117,000 years and brought human ancestors close to extinction."<ref name="NYT-20230831">{{cite news |last=Zimmer |first=Carl |author-link=Carl Zimmer |title=Humanity's Ancestors Nearly Died Out, Genetic Study Suggests - The population crashed following climate change about 930,000 years ago, scientists concluded. Other experts aren't convinced by the analysis. |url= https://www.nytimes.com/2023/08/31/science/human-survival-bottleneck.html |date=August 31, 2023 |work=[[the New York Times]] |archive-url= https://archive.today/20230831182259/https://www.nytimes.com/2023/08/31/science/human-survival-bottleneck.html |archive-date=August 31, 2023 |access-date=September 2, 2023}}</ref><ref name="SCI-20230831">{{cite journal |last=Hu |first=Wangjie |display-authors=etal |title=Genomic inference of a severe human bottleneck during the Early to Middle Pleistocene transition |url= http://www.science.org/doi/10.1126/science.abq7487 |date=August 31, 2023 |journal=[[Science (journal)|Science]] |volume=381 |issue=6661 |pages=979–984 |doi=10.1126/science.abq7487 |pmid=37651513 |bibcode=2023Sci...381..979H |s2cid=261396309 |archive-url= https://archive.today/20230901024052/https://www.science.org/doi/10.1126/science.abq7487 |archive-date=September 1, 2023 |access-date=September 2, 2023}}</ref>

=== ''H. habilis'' and ''H. gautengensis'' ===
''Homo habilis'' lived from about 2.8<ref name="autogenerated1" /> to 1.4 Ma. The species evolved in South and East Africa in the [[Piacenzian|Late Pliocene]] or [[Early Pleistocene]], 2.5–2 Ma, when it diverged from the australopithecines with the development of smaller molars and larger brains. One of the first known hominins, it made [[stone tool|tools from stone]] and perhaps animal bones, leading to its name ''homo'' ''habilis'' (Latin 'handy man') bestowed by discoverer [[Louis Leakey]]. Some scientists have proposed moving this species from ''Homo'' into ''Australopithecus'' due to the morphology of its skeleton being more adapted to [[Arboreal locomotion|living in trees]] rather than [[Bipedalism|walking on two legs]] like later hominins.<ref>{{cite journal |last1=Wood |first1=Bernard |last2=Collard |first2=Mark |date=1999 |title=The changing face of Genus ''Homo'' |journal=Evolutionary Anthropology: Issues, News, and Reviews |volume=8 |issue=6 |pages=195–207 |doi=10.1002/(SICI)1520-6505(1999)8:6<195::AID-EVAN1>3.0.CO;2-2 |s2cid=86768101 |issn=1060-1538}}</ref>

In May 2010, a new species, ''[[Homo gautengensis]]'', was discovered in South Africa.<ref name="toothy">{{cite news |last=Viegas |first=Jennifer |date=May 21, 2010 |title=Toothy Tree-Swinger May Be Earliest Human |url= http://news.discovery.com/human/evolution/human-ancestor-tree-swinger.htm |work=[[Discovery Channel|Discovery News]] |location=Silver Spring, Maryland |publisher=[[Discovery Communications]] |access-date=April 28, 2015 |archive-date=May 9, 2015 |archive-url= https://web.archive.org/web/20150509101320/http://news.discovery.com/human/evolution/human-ancestor-tree-swinger.htm}}</ref>

=== ''H. rudolfensis'' and ''H. georgicus'' ===
These are proposed species names for fossils from about 1.9–1.6 Ma, whose relation to ''Homo habilis'' is not yet clear.
* ''Homo rudolfensis'' refers to a single, incomplete skull from Kenya. Scientists have suggested that this was a specimen of ''Homo habilis'', but this has not been confirmed.<ref>{{cite journal |last=Wood |first=Bernard A. |date=January 1999 |title=''Homo rudolfensis'' Alexeev, 1986 – fact or phantom? |journal=Journal of Human Evolution |volume=36 |issue=1 |pages=115–118 |doi=10.1006/jhev.1998.0246 |issn=0047-2484 |pmid=9924136 |bibcode=1999JHumE..36..115W}}</ref>
* ''[[Homo georgicus]]'', from [[Georgia (country)|Georgia]], may be an intermediate form between ''Homo habilis'' and ''Homo erectus'',<ref>{{cite journal |last1=Gabounia |first1=Léo |last2=de Lumley |first2=Marie-Antoinette |last3=Vekua |first3=Abesalom |last4=Lordkipanidze |first4=David |last5=de Lumley |first5=Henry |date=September 2002 |title=Découverte d'un nouvel hominidé à Dmanissi (Transcaucasie, Géorgie) |trans-title=Discovery of a new hominid at Dmanisi (Transcaucasia, Georgia) |journal=Comptes Rendus Palevol |language=fr |volume=1 |issue=4 |pages=243–253 |doi=10.1016/S1631-0683(02)00032-5 |bibcode=2002CRPal...1..243G |issn=1631-0683 |display-authors=3}}</ref> or a subspecies of ''Homo erectus''.<ref>{{cite journal |last1=Lordkipanidze |first1=David |author1-link=David Lordkipanidze |last2=Vekua |first2=Abesalom |last3=Ferring |first3=Reid |last4=Rightmire |first4=G. Philip |last5=Zollikofer |first5=Christoph P. E. |last6=Ponce de León |first6=Marcia S. |last7=Agusti |first7=Jordi |last8=Kiladze |first8=Gocha |last9=Mouskhelishvili |first9=Alexander |last10=Nioradze |first10=Medea |last11=Tappen |first11=Martha |date=November 2006 |title=A fourth hominin skull from Dmanisi, Georgia |journal=The Anatomical Record Part A: Discoveries in Molecular, Cellular, and Evolutionary Biology |volume=288A |issue=11 |pages=1146–1157 |doi=10.1002/ar.a.20379 |issn=1552-4884 |pmid=17031841 |display-authors=3 |doi-access=free}}</ref>

=== ''H. ergaster'' and ''H. erectus'' ===
[[File:Homo-erectus Turkana-Boy (Ausschnitt) Fundort Nariokotome, Kenia, Rekonstruktion im Neanderthal Museum.jpg|thumb|right|230px|Reconstruction of [[Turkana Boy]] who lived 1.5 to 1.6 million years ago]]
The first fossils of ''Homo erectus'' were discovered by Dutch physician [[Eugene Dubois]] in 1891 on the Indonesian island of Java. He originally named the material ''[[Anthropopithecus]] erectus'' (1892–1893, considered at this point as a chimpanzee-like fossil primate) and ''[[Pithecanthropus]] erectus'' (1893–1894, changing his mind as of based on its morphology, which he considered to be intermediate between that of humans and apes).<ref>{{cite journal |last=Turner |first=William |author-link=William Turner Thiselton-Dyer |date=April 1895 |title=On M. Dubois' Description of Remains recently found in Java, named by him ''Pithecanthropus erectus''. With Remarks on so-called Transitional Forms between Apes and Man |journal=Journal of Anatomy and Physiology |volume=29 |issue=Pt 3 |pages=424–445 |pmc=1328414 |pmid=17232143}}</ref> Years later, in the 20th century, the German physician and [[paleoanthropologist]] [[Franz Weidenreich]] (1873–1948) compared in detail the characters of Dubois' [[Java Man]], then named ''Pithecanthropus erectus'', with the characters of the [[Peking Man]], then named ''Sinanthropus pekinensis''. Weidenreich concluded in 1940 that because of their anatomical similarity with modern humans it was necessary to gather all these specimens of Java and China in a single species of the genus ''Homo'', the species ''H.&nbsp;erectus''.<ref>{{Cite journal |last=Weidenreich |first=Franz |date=July 1940 |title=Some Problems Dealing with Ancient Man |journal=American Anthropologist |volume=42 |issue=3 |pages=375–383 |doi=10.1525/aa.1940.42.3.02a00010 |issn=0002-7294 |doi-access=free}}</ref><ref>{{Citation |last1=Grine |first1=Frederick E. |date=2009 |pages=197–207 |publisher=Springer Netherlands |isbn=978-1-4020-9979-3 |last2=Fleagle |first2=John G. |title=The First Humans – Origin and Early Evolution of the Genus ''Homo'' |chapter=The First Humans: A Summary Perspective on the Origin and Early Evolution of the Genus ''Homo'' |series="Vertebrate Paleobiology and Paleoanthropology" series |doi=10.1007/978-1-4020-9980-9_17}}</ref>

''Homo erectus'' lived from about 1.8 Ma to about 70,000 years ago – which would indicate that they were probably wiped out by the Toba catastrophe; however, nearby ''[[H.&nbsp;floresiensis]]'' survived it. The early phase of ''H.&nbsp;erectus'', from 1.8 to 1.25 Ma, is considered by some to be a separate species, ''H.&nbsp;ergaster'', or as ''H.&nbsp;erectus ergaster'', a subspecies of ''H.&nbsp;erectus''. Many paleoanthropologists now use the term ''Homo ergaster'' for the non-Asian forms of this group, and reserve ''H.&nbsp;erectus'' only for those fossils that are found in Asia and meet certain skeletal and dental requirements which differ slightly from ''H.&nbsp;ergaster''.

In Africa in the Early Pleistocene, 1.5–1 Ma, some populations of ''Homo habilis'' are thought to have evolved larger brains and to have made more elaborate stone tools; these differences and others are sufficient for anthropologists to classify them as a new species, ''Homo erectus''—in Africa.<ref>{{cite journal |last1=Spoor |first1=Fred |last2=Wood |first2=Bernard A. |last3=Zonneveld |first3=Frans |date=June 23, 1994 |title=Implications of early hominid labyrinthine morphology for evolution of human bipedal locomotion |journal=[[Nature (journal)|Nature]] |volume=369 |issue=6482 |pages=645–648 |bibcode=1994Natur.369..645S |doi=10.1038/369645a0 |issn=0028-0836 |pmid=8208290 |s2cid=4344784}}</ref> This species also may have used fire to cook meat. [[Catching Fire: How Cooking Made Us Human|Richard Wrangham]]  notes that ''Homo'' seems to have been ground dwelling, with reduced intestinal length, smaller dentition, and "brains [swollen] to their current, horrendously fuel-inefficient size",<ref>{{Cite news |last=Ings |first=Simon |url= https://www.telegraph.co.uk/culture/books/6250132/Catching-Fire-How-Cooking-Made-Us-Human-by-Richard-Wrangham-review.html |archive-url= https://ghostarchive.org/archive/20220111/https://www.telegraph.co.uk/culture/books/6250132/Catching-Fire-How-Cooking-Made-Us-Human-by-Richard-Wrangham-review.html |archive-date=January 11, 2022 |url-access=subscription |url-status=live |title=''Catching Fire: How Cooking Made Us Human'' by Richard Wrangham: Review |access-date=February 23, 2016 |date=October 4, 2009}}{{cbignore}}</ref> and hypothesizes that control of fire and cooking, which released increased nutritional value, was the key adaptation that separated ''Homo'' from tree-sleeping Australopithecines.<ref>{{cite book |last=Wrangham |first=Richard |date=2011 |title=Catching Fire: How cooking made us human}}{{page needed|date=December 2021}}</ref>
{{See also|Control of fire by early humans}}

=== ''H. cepranensis'' and ''H. antecessor'' ===
These are proposed as species intermediate between ''H.&nbsp;erectus'' and ''H.&nbsp;heidelbergensis''.
* ''H. antecessor'' is known from fossils from Spain and England that are dated 1.2 Ma–500 [[Year#SI prefix multipliers|ka]].<ref>{{cite journal |last1=Bermúdez de Castro |first1=José María |last2=Arsuaga |first2=Juan Luis |author2-link=Juan Luis Arsuaga |last3=Carbonell |first3=Eudald |author3-link=Eudald Carbonell |last4=Rosas |first4=Antonio |last5=Martínez |first5=I. |last6=Mosquera |first6=Marina |date=May 30, 1997 |title=A Hominid from the Lower Pleistocene of Atapuerca, Spain: Possible Ancestor to Neandertals and Modern Humans |journal=[[Science (journal)|Science]] |volume=276 |issue=5317 |pages=1392–1395 |doi=10.1126/science.276.5317.1392 |issn=0036-8075 |pmid=9162001 |display-authors=3}}</ref><ref>{{cite journal |last1=Carbonell |first1=Eudald |last2=Bermúdez de Castro |first2=José María |last3=Parés |first3=Josep M. |last4=Pérez-González |first4=A. |last5=Cuenca-Bescós |first5=G. |last6=Ollé |first6=A. |last7=Mosquera |first7=M. |last8=Huguet |first8=R. |last9=Van Der Made |first9=J. |last10=Rosas |first10=A. |last11=Sala |first11=R. |last12=Vallverdú |first12=J. |last13=García |first13=N. |last14=Granger |first14=D. E. |last15=Martinón-Torres |first15=M. |last16=Rodríguez |first16=X. P. |last17=Stock |first17=G. M. |last18=Vergès |first18=J. M. |last19=Allué |first19=E. |last20=Burjachs |first20=F. |last21=Cáceres |first21=I. |last22=Canals |first22=A. |last23=Benito |first23=A. |last24=Díez |first24=C. |last25=Lozano |first25=M. |last26=Mateos |first26=A. |last27=Navazo |first27=M. |last28=Rodríguez |first28=J. |last29=Rosell |first29=J. |last30=Arsuaga |first30=J. L. |date=March 27, 2008 |title=The first hominin of Europe |journal=[[Nature (journal)|Nature]] |volume=452 |issue=7186 |pages=465–469 |bibcode=2008Natur.452..465C |doi=10.1038/nature06815 |issn=0028-0836 |pmid=18368116 |display-authors=3 |hdl=2027.42/62855 |s2cid=4401629 |hdl-access=free}}</ref>
* ''[[Homo cepranensis|H. cepranensis]]'' refers to a single skull cap from Italy, estimated to be about 800,000 years old.<ref>{{cite journal |last1=Manzi |first1=Giorgio |last2=Mallegni |first2=Francesco |author2-link=Francesco Mallegni |last3=Ascenzi |first3=Antonio |date=August 14, 2001 |title=A cranium for the earliest Europeans: Phylogenetic position of the hominid from Ceprano, Italy |journal=[[Proceedings of the National Academy of Sciences of the United States of America]] |volume=98 |issue=17 |pages=10011–10016 |bibcode=2001PNAS...9810011M |doi=10.1073/pnas.151259998 |issn=0027-8424 |pmc=55569 |pmid=11504953 |doi-access=free}}</ref>

=== ''H. heidelbergensis'' ===
{{Main|Homo heidelbergensis}}
''H. heidelbergensis'' ("Heidelberg Man") lived from about 800,000 to about 300,000 years ago. Also proposed as ''Homo sapiens heidelbergensis'' or ''Homo sapiens paleohungaricus''.<ref>{{cite journal |last1=Czarnetzki |first1=Alfred |last2=Jakob |first2=Tina |last3=Pusch |first3=Carsten M. |date=April 2003 |title=Palaeopathological and variant conditions of the ''Homo heidelbergensis'' type specimen (Mauer, Germany) |journal=Journal of Human Evolution |volume=44 |issue=4 |pages=479–495 |doi=10.1016/S0047-2484(03)00029-0 |issn=0047-2484 |pmid=12727464 |bibcode=2003JHumE..44..479C}}</ref>

=== ''H. rhodesiensis'', and the Gawis cranium ===
* ''H. rhodesiensis'', estimated to be 300,000–125,000 years old. Most current researchers place Rhodesian Man within the group of ''Homo heidelbergensis'', though other designations such as archaic ''Homo sapiens'' and ''Homo sapiens rhodesiensis'' have been proposed.
* In February 2006 a fossil, the [[Gawis cranium]], was found which might possibly be a species intermediate between ''H.&nbsp;erectus'' and ''H.&nbsp;sapiens'' or one of many evolutionary dead ends. The skull from Gawis, Ethiopia, is believed to be 500,000–250,000 years old. Only summary details are known, and the finders have not yet released a peer-reviewed study. Gawis man's facial features suggest that it is either an intermediate species or an example of a "Bodo man" female.<ref>{{cite press release |last1=Semaw |first1=Sileshi |last2=Toth |first2=Nicholas |last3=Schick |first3=Kathy |last4=Simpson |first4=Scott |last5=Quade |first5=Jay |last6=Rogers |first6=Michael J. |date=March 27, 2006 |title=Scientists discover hominid cranium in Ethiopia |url= http://newsinfo.iu.edu/news/page/normal/3142.html |location=Bloomington |publisher=[[Indiana University]] |access-date=November 26, 2006 |display-authors=3 |archive-date=November 15, 2006 |archive-url= https://web.archive.org/web/20061115161617/http://newsinfo.iu.edu/news/page/normal/3142.html |url-status=live}}</ref>

=== Neanderthal and Denisovan ===
{{Main|Neanderthal|Denisovan}}
[[File:Homo sapiens neanderthalensis-Mr. N.jpg|thumb|upright|Reconstruction of an elderly Neanderthal man]]
''Homo neanderthalensis'', alternatively designated as ''Homo sapiens neanderthalensis'',<ref>{{cite journal |last=Harvati |first=Katerina |date=January 2003 |title=The Neanderthal taxonomic position: Models of intra- and inter-specific craniofacial variation |journal=Journal of Human Evolution |volume=44 |issue=1 |pages=107–132 |doi=10.1016/S0047-2484(02)00208-7 |issn=0047-2484 |pmid=12604307 |bibcode=2003JHumE..44..107H}}</ref> lived in Europe and Asia from 400,000<ref>{{Cite journal |last1=Herrera |first1=K. J. |last2=Somarelli |first2=J. A. |last3=Lowery |first3=R. K. |last4=Herrera |first4=R. J. |title=To what extent did Neanderthals and modern humans interact? |date=2009 |journal=Biological Reviews |volume=84 |issue=2 |pages=245–257 |doi=10.1111/j.1469-185X.2008.00071.x |pmid=19391204 |s2cid=25787484}}</ref> to about 28,000 years ago.<ref>{{cite journal |doi=10.1038/nature05195 |pmid=16971951 |title=Late survival of Neanderthals at the southernmost extreme of Europe |journal=[[Nature (journal)|Nature]] |volume=443 |issue=7113 |pages=850–853 |date=2006 |last1=Finlayson |first1=C. |last2=Giles Pacheco |first2=F. |last3=Rodríguez-Vidal |first3=J. |last4=Fa |first4=D. A. |last5=Gutiérrez López |first5=J. M. |last6=Santiago Pérez |first6=A. |last7=Finlayson |first7=G. |last8=Allué |first8=E. |last9=Baena Preysler |first9=J. |last10=Cáceres |first10=I. |last11=Carrión |first11=J. S. |last12=Fernández-Jalvo |first12=Y. |last13=Gleed-Owen |first13=C. P. |last14=Jiménez-Espejo |first14=F. J. |last15=López Martínez |first15=P. |last16=López Sáez |first16=J. A. |last17=Riquelme Cantal |first17=J. A. |last18=Sánchez Marco |first18=A. |last19=Giles Guzmán |first19=F. |last20=Brown |first20=K. |last21=Fuentes |first21=N. |last22=Valarino |first22=C. A. |last23=Villalpando |first23=A. |last24=Stringer |first24=C. B. |last25=Martínez Ruíz |first25=F. C. |last26=Sakamoto |first26=T. |display-authors=3 |bibcode=2006Natur.443..850F |hdl=10261/18685 |s2cid=4411186}}{{collapsible list |title=Full list of authors |bullets=true |Clive Finlayson |Francisco Giles Pacheco |Joaquín Rodríguez-Vidal |Darren A. Fa |José María Gutierrez López |Antonio Santiago Pérez |Geraldine Finlayson |Ethel Allue |Javier Baena Preysler |Isabel Cáceres |José S. Carrión |Yolanda Fernández-Jalvo |Christopher P. Gleed-Owen |Francisco J. Jimenez-Espejo |Pilar López Martínez |José Antonio López Sáez |José Antonio Riquelme Cantal |Antonio Sánchez Marco |Francisco Giles Guzman |Kimberly Brown |Noemí Fuentes |Claire A. Valarino |Antonio Villalpando |Christopher B. Stringer |Francisca Martinez Ruiz |Tatsuhiko Sakamoto}}</ref>
There are a number of clear anatomical differences between [[anatomically modern humans]] (AMH) and Neanderthal specimens, many relating to the superior Neanderthal adaptation to cold environments. Neanderthal [[surface to volume ratio]] was even lower than that among modern [[Inuit]] populations, indicating superior retention of body heat.

Neanderthals also had significantly larger brains, as shown from brain endocasts, casting doubt on their intellectual inferiority to modern humans. However, the higher body mass of Neanderthals may have required larger brain mass for body control.<ref name="dunbar">{{Cite journal |last1=Pearce |first1=Eiluned |last2=Stringer |first2=Chris |last3=Dunbar |first3=R. I. M. |date=2013 |title=New insights into differences in brain organization between Neanderthals and anatomically modern humans |journal=Proceedings of the Royal Society of London B: Biological Sciences |volume=280 |issue=1758 |page=20130168 |doi=10.1098/rspb.2013.0168 |pmc=3619466 |pmid=23486442}}</ref> Also, recent research by Pearce, [[Chris Stringer|Stringer]], and Dunbar has shown important differences in brain architecture. The larger size of the Neanderthal orbital chamber and [[occipital lobe]] suggests that they had a better visual acuity than modern humans, useful in the dimmer light of glacial Europe.

Neanderthals may have had less [[Dunbar's number|brain capacity available for social functions]]. Inferring social group size from endocranial volume (minus occipital lobe size) suggests that Neanderthal groups may have been limited to 120 individuals, compared to 144{{cn|date=January 2024}}<ref>{{Cite journal |last1=Bocquet-Appel |first1=Jean-Pierre |last2=Degioanni |first2=Anna |date=December 2013 |title=Neanderthal Demographic Estimates |url= https://www.journals.uchicago.edu/doi/full/10.1086/673725# |journal=The University of Chicago Press Journals |volume=54 |issue=S8 |pages=S202–S213 |doi=10.1086/673725}}</ref> possible relationships for modern humans. Larger social groups could imply that modern humans had less risk of inbreeding within their clan, trade over larger areas (confirmed in the distribution of stone tools), and faster spread of social and technological innovations. All these may have all contributed to modern ''Homo sapiens'' replacing Neanderthal populations by 28,000 BP.<ref name="dunbar" />

Earlier evidence from sequencing mitochondrial DNA suggested that no significant gene flow occurred between ''H. neanderthalensis'' and ''H. sapiens'', and that the two were separate species that shared a common ancestor about 660,000 years ago.<ref>{{cite journal |last1=Krings |first1=Matthias |last2=Stone |first2=Anne |last3=Schmitz |first3=Ralf W. |last4=Krainitzki |first4=Heike |last5=Stoneking |first5=Mark |last6=Pääbo |first6=Svante |date=July 11, 1997 |title=Neandertal DNA sequences and the origin of modern humans |journal=[[Cell (journal)|Cell]] |volume=90 |issue=1 |pages=19–30 |doi=10.1016/S0092-8674(00)80310-4 |issn=0092-8674 |pmid=9230299 |hdl=11858/00-001M-0000-0025-0960-8 |s2cid=13581775 |display-authors=3 |hdl-access=free}}</ref><ref>{{cite journal |last1=Green |first1=Richard E. |last2=Malaspinas |first2=Anna-Sapfo |last3=Krause |first3=Johannes |last4=Briggs |first4=Adrian W. |last5=Johnson |first5=Philip L.F. |last6=Uhler |first6=Caroline |last7=Meyer |first7=Matthias |last8=Good |first8=Jeffrey M. |last9=Maricic |first9=Tomislav |last10=Stenzel |first10=Udo |last11=Prüfer |first11=Kay |last12=Siebauer |first12=Michael |last13=Burbano |first13=Hernán A. |last14=Ronan |first14=Michael |last15=Rothberg |first15=Jonathan M. |last16=Egholm |first16=Michael |last17=Rudan |first17=Pavao |last18=Brajković |first18=Dejana |last19=Kućan |first19=Željko |last20=Gušić |first20=Ivan |last21=Wikström |first21=Mårten |last22=Laakkonen |first22=Liisa |last23=Kelso |first23=Janet |last24=Slatkin |first24=Montgomery |last25=Pääbo |first25=Svante |date=August 8, 2008 |title=A Complete Neandertal Mitochondrial Genome Sequence Determined by High-Throughput Sequencing |journal=Cell |volume=134 |issue=3 |pages=416–426 |doi=10.1016/j.cell.2008.06.021 |issn=0092-8674 |pmc=2602844 |pmid=18692465 |display-authors=3}}</ref><ref>{{cite journal |last1=Serre |first1=David |last2=Langaney |first2=André |last3=Chech |first3=Mario |last4=Teschler-Nicola |last5=Paunovic |last6=Mennecier |last7=Hofreiter |last8=Possnert |last9=Pääbo |date=March 2004 |title=No Evidence of Neandertal mtDNA Contribution to Early Modern Humans |journal=PLOS Biology |volume=2 |issue=3 |page=e57 |doi=10.1371/journal.pbio.0020057 |issn=1545-7885 |pmc=368159 |pmid=15024415 |display-authors=3 |doi-access=free}}</ref> However, a sequencing of the Neanderthal genome in 2010 indicated that Neanderthals did indeed interbreed with anatomically modern humans c. 45,000-80,000 years ago, around the time modern humans migrated out from Africa, but before they dispersed throughout Europe, Asia and elsewhere.<ref name="neandersequence">{{cite news |last=Viegas |first=Jennifer |date=May 6, 2010 |title=Neanderthals, Humans Interbred, DNA Proves |url= http://news.discovery.com/human/evolution/neanderthal-human-interbreed-dna.htm |work=Discovery News |location=Silver Spring, Maryland |publisher=[[Discovery Communications]] |access-date=April 30, 2015 |archive-url= https://web.archive.org/web/20150508221757/http://news.discovery.com/human/evolution/neanderthal-human-interbreed-dna.htm |archive-date=May 8, 2015}}</ref> The genetic sequencing of a 40,000-year-old [[Peștera cu Oase|human skeleton from Romania]] showed that 11% of its genome was Neanderthal, implying the individual had a Neanderthal ancestor 4–6 generations previously,<ref>{{cite journal |last=Calloway |first=Ewan |title=Early European may have had Neanderthal great-great-grandparent |journal=[[Nature (journal)|Nature]] |date=May 13, 2015 |url= https://www.nature.com/news/early-european-may-have-had-neanderthal-great-great-grandparent-1.17534 |doi=10.1038/nature.2015.17534 |s2cid=181973496 |access-date=January 23, 2019 |archive-date=January 15, 2019 |archive-url= https://web.archive.org/web/20190115110342/http://www.nature.com/news/early-european-may-have-had-neanderthal-great-great-grandparent-1.17534 |url-status=live}}</ref> in addition to a contribution from earlier interbreeding in the Middle East. Though this interbred Romanian population seems not to have been ancestral to modern humans, the finding indicates that interbreeding happened repeatedly.<ref>{{cite news |last=Sample |first=Ian |title=My Neanderthal sex secret: Modern European's great-great grandparent link |newspaper=[[The Guardian]] |date=June 22, 2015 |access-date=July 27, 2018 |url= https://www.theguardian.com/science/2015/jun/22/my-neanderthal-sex-secret-modern-europeans-great-great-grandparent-link |archive-date=September 23, 2016 |archive-url= https://web.archive.org/web/20160923235758/https://www.theguardian.com/science/2015/jun/22/my-neanderthal-sex-secret-modern-europeans-great-great-grandparent-link |url-status=live}}</ref>

All modern non-African humans have about 1% to 4% (or 1.5% to 2.6% by more recent data) of their DNA derived from Neanderthals.<ref name="greenetal" /><ref name="neandersequence" /><ref name="A high-coverage Neandertal genome f" /> This finding is consistent with recent studies indicating that the divergence of some human alleles dates to one Ma, although this interpretation has been questioned.<ref>{{cite journal |last1=Gutiérrez |first1=Gabriel |last2=Sánchez |first2=Diego |last3=Marín |first3=Antonio |date=August 2002 |title=A Reanalysis of the Ancient Mitochondrial DNA Sequences Recovered from Neandertal Bones |journal=Molecular Biology and Evolution |volume=19 |issue=8 |pages=1359–1366 |doi=10.1093/oxfordjournals.molbev.a004197 |issn=0737-4038 |pmid=12140248 |doi-access=free}}</ref><ref>{{cite journal |last1=Hebsgaard |first1=M. B. |last2=Wiuf |first2=C. |last3=Gilbert |first3=M. T. |last4=Glenner |first4=H. |last5=Willerslev |first5=E. |date=January 2007 |title=Evaluating Neanderthal Genetics and Phylogeny |journal=Journal of Molecular Evolution |volume=64 |issue=1 |pages=50–60 |doi=10.1007/s00239-006-0017-y |issn=0022-2844 |pmid=17146600 |s2cid=2746487 |url= http://www.birc.au.dk/%7Ewiuf/journalWiuf/jMolEvol64.pdf |archive-url= https://wayback.archive-it.org/all/20110401041826/http://www.birc.au.dk/~wiuf/journalWiuf/jMolEvol64.pdf |archive-date=April 1, 2011 |access-date=October 24, 2017 |citeseerx=10.1.1.174.8969 |bibcode=2007JMolE..64...50H}}</ref> Neanderthals and AMH ''Homo sapiens'' could have co-existed in Europe for as long as 10,000 years, during which AMH populations exploded, vastly outnumbering Neanderthals, possibly outcompeting them by sheer numbers.<ref>{{cite journal |last1=Mellars |first1=Paul |last2=French |first2=Jennifer C. |date=July 29, 2011 |title=Tenfold Population Increase in Western Europe at the Neandertal–to–Modern Human Transition Paul |journal=[[Science (journal)|Science]] |volume=333 |issue=6042 |pages=623–627 |bibcode=2011Sci...333..623M |doi=10.1126/science.1206930 |issn=0036-8075 |pmid=21798948 |s2cid=28256970}}</ref>

In 2008, archaeologists working at the site of [[Denisova Cave]] in the [[Altai Mountains]] of [[Siberia]] uncovered a small bone fragment from the fifth finger of a juvenile member of another human species, the Denisovans.<ref>{{cite journal |last=Brown |first=Terence A. |date=April 8, 2010 |title=Human evolution: Stranger from Siberia |journal=[[Nature (journal)|Nature]] |volume=464 |issue=7290 |pages=838–839 |bibcode=2010Natur.464..838B |doi=10.1038/464838a |issn=0028-0836 |pmid=20376137 |s2cid=4320406 |doi-access=free}}</ref> Artifacts, including a bracelet, excavated in the cave at the same level were [[Radiocarbon dating|carbon dated]] to around 40,000 BP. As DNA had survived in the fossil fragment due to the cool climate of the Denisova Cave, both mtDNA and nuclear DNA were sequenced.<ref name="pmid21179161" /><ref name="Pääbo et al.">{{cite journal |last1=Krause |first1=Johannes |author1-link=Johannes Krause |last2=Fu |first2=Qiaomei |last3=Good |first3=Jeffrey M. |last4=Viola |first4=Bence |last5=Shunkov |first5=Michael V. |last6=Derevianko |first6=Anatoli P. |last7=Pääbo |first7=Svante |author7-link=Svante Pääbo |display-authors=3 |date=April 8, 2010 |title=The complete mitochondrial DNA genome of an unknown hominin from southern Siberia |journal=[[Nature (journal)|Nature]] |volume=464 |issue=7290 |pages=894–897 |bibcode=2010Natur.464..894K |doi=10.1038/nature08976 |issn=0028-0836 |pmid=20336068 |pmc=10152974 |s2cid=4415601 |doi-access=free}}</ref>

While the divergence point of the mtDNA was unexpectedly deep in time,<ref name="The Scientist">{{cite news |last=Katsnelson |first=Alla |date=March 24, 2010 |title=New hominin found via mtDNA |url= http://www.the-scientist.com/?articles.view/articleNo/28876/title/New-hominin-found-via-mtDNA/#ixzz0j820ioz1 |work=The Nutshell |type=Blog |location=Philadelphia |publisher=[[The Scientist (magazine)|The Scientist]] |issn=0890-3670 |access-date=May 1, 2015 |archive-date=July 2, 2015 |archive-url= https://web.archive.org/web/20150702154449/http://www.the-scientist.com/?articles.view/articleNo/28876/title/New-hominin-found-via-mtDNA/#ixzz0j820ioz1 |url-status=live}}</ref> the full genomic sequence suggested the Denisovans belonged to the same lineage as Neanderthals, with the two diverging shortly after their line split from the lineage that gave rise to modern humans.<ref name="pmid21179161" /> Modern humans are known to have overlapped with Neanderthals in Europe and the Near East for possibly more than 40,000 years,<ref>"Kaufman, Danial (2002), "Comparisons and the Case for Interaction among Neanderthals and Early Modern Humans in the Levant" (Oxford Journal of Anthropology)</ref> and the discovery raises the possibility that Neanderthals, Denisovans, and modern humans may have co-existed and interbred. The existence of this distant branch creates a much more complex picture of humankind during the [[Late Pleistocene]] than previously thought.<ref name="Pääbo et al." /><ref>{{cite journal |last1=Bokma |first1=Folmer |last2=van den Brink |first2=Valentijn |last3=Stadler |first3=Tanja |date=September 2012 |title=Unexpectedly many extinct hominins |journal=[[Evolution (journal)|Evolution]] |volume=66 |issue=9 |pages=2969–2974 |doi=10.1111/j.1558-5646.2012.01660.x |issn=0014-3820 |pmid=22946817 |s2cid=13145359 |doi-access=free}}</ref> Evidence has also been found that as much as 6% of the DNA of some modern [[Melanesians]] derive from Denisovans, indicating limited interbreeding in Southeast Asia.<ref name="Reich_2011" /><ref>{{cite journal |last1=Martinón-Torres |first1=María |last2=Dennell |first2=Robin |last3=Bermúdez de Castro |first3=José María |date=February 2011 |title=The Denisova hominin need not be an out of Africa story |journal=Journal of Human Evolution |volume=60 |issue=2 |pages=251–255 |doi=10.1016/j.jhevol.2010.10.005 |issn=0047-2484 |pmid=21129766 |bibcode=2011JHumE..60..251M}}</ref>

Alleles thought to have originated in Neanderthals and Denisovans have been identified at several genetic loci in the genomes of modern humans outside Africa. [[Human leukocyte antigen]] (HLA) haplotypes from Denisovans and Neanderthal represent more than half the HLA alleles of modern Eurasians,<ref name="10.1126/science.1209202" /> indicating strong positive selection for these [[introgressed]] alleles. Corinne Simoneti at Vanderbilt University, in Nashville and her team have found from medical records of 28,000 people of European descent that the presence of Neanderthal DNA segments may be associated with a higher rate of depression.<ref>{{Cite journal |doi=10.1126/science.aad2149 |pmid=26912863 |pmc=4849557 |title=The phenotypic legacy of admixture between modern humans and Neandertals |journal=[[Science (journal)|Science]] |volume=351 |issue=6274 |pages=737–741 |date=2016 |last1=Simonti |first1=C. N. |last2=Vernot |first2=B. |last3=Bastarache |first3=L. |last4=Bottinger |first4=E. |last5=Carrell |first5=D. S. |last6=Chisholm |first6=R. L. |last7=Crosslin |first7=D. R. |last8=Hebbring |first8=S. J. |last9=Jarvik |first9=G. P.| last10=Kullo| first10=I. J. |last11=Li |first11=R. |last12=Pathak |first12=J. |last13=Ritchie |first13=M. D. |last14=Roden |first14=D. M. |last15=Verma |first15=S. S. |last16=Tromp |first16=G. |last17=Prato |first17=J. D. |last18=Bush |first18=W. S. |last19=Akey |first19=J. M. |last20=Denny |first20=J. C. |last21=Capra |first21=J. A. |bibcode=2016Sci...351..737S}}</ref>

The flow of genes from Neanderthal populations to modern humans was not all one way. Sergi Castellano of the Max Planck Institute for [[Evolutionary Anthropology]] reported in 2016 that while Denisovan and Neanderthal genomes are more related to each other than they are to us, Siberian Neanderthal genomes show more similarity to modern human genes than do European Neanderthal populations. This suggests Neanderthal populations interbred with modern humans around 100,000 years ago, probably somewhere in the Near East.<ref>{{cite journal |volume=530 |issue=7591 |title=Ancient gene flow from early modern humans into Eastern Neanderthals |journal=[[Nature (journal)|Nature]] |pages=429–433 |pmid=26886800 |pmc=4933530 |last1=Kuhlwilm |first1=M. |last2=Gronau |first2=I. |last3=Hubisz |first3=M. J. |last4=de Filippo |first4=C. |last5=Prado-Martinez |first5=J. |last6=Kircher |first6=M. |last7=Fu |first7=Q. |last8=Burbano |first8=H. A. |last9=Lalueza-Fox |first9=C. |last10=de la Rasilla |first10=M. |last11=Rosas |first11=A. |last12=Rudan |first12=P. |last13=Brajkovic |first13=D. |last14=Kucan |first14=Ž. |last15=Gušic |first15=I. |last16=Marques-Bonet |first16=T. |last17=Andrés |first17=A. M. |last18=Viola |first18=B. |last19=Pääbo |first19=S. |author19-link=Svante Pääbo |last20=Meyer |first20=M. |last21=Siepel |first21=A. |last22=Castellano |first22=S. |doi=10.1038/nature16544 |bibcode=2016Natur.530..429K |date=2016}}</ref>

Studies of a Neanderthal child at Gibraltar show from brain development and tooth eruption that Neanderthal children may have matured more rapidly than ''Homo sapiens''.<ref>Dean, MC, Stringer, CB et al, (1986) "Age at death of the Neanderthal child from Devil's Tower, Gibraltar and the implications for studies of general growth and development in Neanderthals" (American Journal of Physical Anthropology, Vol 70 Issue 3, July 1986)</ref>

=== ''H. floresiensis'' ===
{{Main|Homo floresiensis}}
[[File:Homo floresiensis v 2-0.jpg|thumb|200px|A facial reconstruction of ''Homo floresiensis''|left]]
''H. floresiensis'', which lived from approximately 190,000 to 50,000 years [[before present]] (BP), has been nicknamed the ''[[hobbit]]'' for its small size, possibly a result of [[insular dwarfism]].<ref name=":0">{{cite journal |last1=Brown |first1=P. |last2=Sutikna |first2=T. |last3=Morwood |first3=M. J. |last4=Soejono |first4=R. P. |last5=Jatmiko |first5=A. |last6=Wayhu |first6=S. E. |last7=Awe Due |first7=R. |author3-link=Mike Morwood |author4-link=Raden Panji Soejono |date=October 28, 2004 |title=A new small-bodied hominin from the Late Pleistocene of Flores, Indonesia |journal=[[Nature (journal)|Nature]] |volume=431 |issue=7012 |pages=1055–1061 |bibcode=2004Natur.431.1055B |doi=10.1038/nature02999 |issn=0028-0836 |pmid=15514638 |s2cid=26441 |url= http://doc.rero.ch/record/15287/files/PAL_E2586.pdf |access-date=January 3, 2023 |archive-date=January 3, 2023 |archive-url= https://web.archive.org/web/20230103195019/http://doc.rero.ch/record/15287/files/PAL_E2586.pdf |url-status=live}}</ref> ''H. floresiensis'' is intriguing both for its size and its age, being an example of a recent species of the genus ''Homo'' that exhibits derived traits not shared with modern humans. In other words, ''H. floresiensis'' shares a common ancestor with modern humans, but split from the modern human lineage and followed a distinct evolutionary path. The main find was a skeleton believed to be a woman of about 30 years of age. Found in 2003, it has been dated to approximately 18,000 years old. The living woman was estimated to be one meter in height, with a brain volume of just 380&nbsp;cm<sup>3</sup> (considered small for a chimpanzee and less than a third of the ''H.&nbsp;sapiens'' average of 1400&nbsp;cm<sup>3</sup>).<ref name=":0" />

However, there is an ongoing debate over whether ''H.&nbsp;floresiensis'' is indeed a separate species.<ref name=":1">{{cite journal |last1=Argue |first1=Debbie |last2=Donlon |first2=Denise |last3=Groves |first3=Colin |author3-link=Colin Groves |last4=Wright |first4=Richard |date=October 2006 |title=''Homo floresiensis'': Microcephalic, pygmoid, ''Australopithecus'', or ''Homo''? |journal=Journal of Human Evolution |volume=51 |issue=4 |pages=360–374 |doi=10.1016/j.jhevol.2006.04.013 |issn=0047-2484 |pmid=16919706 |bibcode=2006JHumE..51..360A}}</ref> Some scientists hold that ''H. floresiensis'' was a modern ''H. sapiens'' with pathological dwarfism.<ref name="Martin">{{cite journal |last1=Martin |first1=Robert D. |author1-link=Robert D. Martin |last2=Maclarnon |first2=Ann M. |last3=Phillips |first3=James L. |last4=Dobyns |first4=William B. |date=November 2006 |title=Flores hominid: New species or microcephalic dwarf? |journal=The Anatomical Record Part A: Discoveries in Molecular, Cellular, and Evolutionary Biology |volume=288A |issue=11 |pages=1123–1145 |doi=10.1002/ar.a.20389 |issn=1552-4884 |pmid=17031806 |doi-access=free}}</ref> This hypothesis is supported in part, because some modern humans who live on [[Flores]], the Indonesian island where the skeleton was found, are [[Pygmy peoples|pygmies]]. This, coupled with pathological dwarfism, could have resulted in a significantly diminutive human. The other major attack on ''H. floresiensis'' as a separate species is that it was found with tools only associated with ''H. sapiens''.<ref name="Martin" />

The hypothesis of pathological dwarfism, however, fails to explain additional [[Homo floresiensis#Anatomy|anatomical features]] that are unlike those of modern humans (diseased or not) but much like those of ancient members of our genus. Aside from cranial features, these features include the form of bones in the wrist, forearm, shoulder, knees, and feet. Additionally, this hypothesis fails to explain the find of multiple examples of individuals with these same characteristics, indicating they were common to a large population, and not limited to one individual.<ref name=":1" />

In 2016, fossil teeth and a partial jaw from hominins assumed to be ancestral to ''H.&nbsp;floresiensis'' were discovered<ref name="Callaway2016b">{{cite journal |last=Callaway |first=E. |title='Hobbit' relatives found after ten-year hunt |journal=[[Nature (journal)|Nature]] |volume=534 |issue=7606 |date=June 8, 2016 |pages=164–165 |doi=10.1038/534164a |pmid=27279191 |bibcode=2016Natur.534Q.164C |doi-access=free}}</ref> at [[Mata Menge]], about {{cvt|74|km}} from Liang Bua. They date to about 700,000 years ago<ref name="Brumm2016">{{cite journal |last1=Brumm |first1=A. |last2=van den Bergh |first2=G. D. |last3=Storey |first3=M. |last4=Kurniawan |first4=I. |last5=Alloway |first5=B. V. |last6=Setiawan |first6=R. |last7=Setiyabudi |first7=E. |last8=Grün |first8=R. |last9=Moore |first9=M. W. |last10=Yurnaldi |first10=D. |last11=Puspaningrum |first11=M. R. |last12=Wibowo |first12=U. P. |last13=Insani |first13=H. |last14=Sutisna |first14=I. |last15=Westgate |first15=J. A. |last16=Pearce |first16=N. J. G. |last17=Duval |first17=M. |last18=Meijer |first18=H. J. M. |last19=Aziz |first19=F. |last20=Sutikna |first20=T. |last21=van der Kaars |first21=S. |last22=Flude |first22=S. |last23=Morwood |first23=M. J. |display-authors=4 |title=Age and context of the oldest known hominin fossils from Flores |journal=[[Nature (journal)|Nature]] |volume=534 |issue=7606 |date=June 8, 2016 |pages=249–253 |pmid=27279222 |doi=10.1038/nature17663 |bibcode=2016Natur.534..249B |s2cid=28608179 |url= http://pure.aber.ac.uk/ws/files/9400924/Brumm_et_al_2016_Age_stratigraphic_context_hominin_fossils_Flores_NAture_DRAFT_MS.pdf |access-date=November 11, 2021 |archive-date=March 6, 2020 |archive-url= https://web.archive.org/web/20200306112537/http://pure.aber.ac.uk/ws/files/9400924/Brumm_et_al_2016_Age_stratigraphic_context_hominin_fossils_Flores_NAture_DRAFT_MS.pdf |url-status=live}}{{collapsible list |title=Full list of authors |bullets=true |Adam Brumm |Gerrit D. van den Bergh |Michael Storey |Iwan Kurniawan |Brent V. Alloway |Ruly Setiawan |Erick Setiyabudi |Rainer Grün |Mark W. Moore |Dida Yurnaldi |Mika R. Puspaningrum |Unggul P. Wibowo |Halmi Insani |Indra Sutisna |John A. Westgate |Nick J. G. Pearce |Mathieu Duval |Hanneke J. M. Meijer |Fachroel Aziz |Thomas Sutikna |Sander van der Kaars |Stephanie Flude |Michael J. Morwood}}</ref> and are noted by Australian archaeologist Gerrit van den Bergh for being even smaller than the later fossils.<ref>{{cite journal |last1=van den Bergh |first1=G. D. |last2=Kaifu |first2=Y. |last3=Kurniawan |first3=I. |last4=Kono |first4=R. T. |last5=Brumm |first5=A. |last6=Setiyabudi |first6=E. |last7=Aziz |first7=F. |last8=Morwood |first8=M. J. |title=''Homo floresiensis''-like fossils from the early Middle Pleistocene of Flores |journal=[[Nature (journal)|Nature]] |volume=534 |issue=7606 |date=June 8, 2016 |pages=245–248 |doi=10.1038/nature17999 |pmid=27279221 |bibcode=2016Natur.534..245V |s2cid=205249218}}</ref>

=== ''H. luzonensis'' ===
{{Main|Homo luzonensis}}
A small number of specimens from the island of [[Luzon]], dated 50,000 to 67,000 years ago, have recently been assigned by their discoverers, based on dental characteristics, to a novel human species, ''H. luzonensis''.<ref>{{cite journal |last1=Détroit |first1=F. |last2=Mijares |first2=A. S. |last3=Corny |first3=J. |last4=Daver |first4=G. |last5=Zanolli |first5=C. |last6=Dizon |first6=E. |last7=Robles |first7=E. |last8=Grün |first8=R. |last9=Piper |first9=P. J. |name-list-style=amp |date=2019 |title=A new species of ''Homo'' from the Late Pleistocene of the Philippines |journal=[[Nature (journal)|Nature]] |volume=568 |issue=7751 |pages=181–186 |doi=10.1038/s41586-019-1067-9 |pmid=30971845 |bibcode=2019Natur.568..181D |s2cid=106411053 |url= https://hal.archives-ouvertes.fr/hal-02296712/file/Detroit_%26_al_2019_Nature_postprint.pdf |access-date=May 11, 2021 |archive-date=October 13, 2022 |archive-url= https://web.archive.org/web/20221013114830/https://hal.archives-ouvertes.fr/hal-02296712/file/Detroit_%26_al_2019_Nature_postprint.pdf |url-status=live}}</ref>

=== ''H. sapiens'' ===
{{Main|Archaic humans|Early modern human|Interbreeding between archaic and modern humans|Human#Evolution}}
[[File:Homo sapiens sapiens (Fundort Jebel Irhoud Marokko).jpg|thumb|200px|Reconstruction of early ''Homo sapiens'' from [[Jebel Irhoud]], Morocco {{c.|315 000 years BP}}]]
''H. sapiens'' (the adjective ''[[wikt:sapiens|sapiens]]'' is Latin for "wise" or "intelligent") emerged in Africa around 300,000 years ago, likely derived from ''[[H.&nbsp;heidelbergensis]]'' or a related lineage.<ref name="Schlebusch2017">{{cite journal |doi=10.1126/science.aao6266 |pmid=28971970 |title=Southern African ancient genomes estimate modern human divergence to 350,000 to 260,000 years ago |journal=[[Science (journal)|Science]] |volume=358 |issue=6363 |pages=652–655 |date=2017 |last1=Schlebusch |first1=Carina M. |last2=Malmström |first2=Helena |last3=Günther |first3=Torsten |last4=Sjödin |first4=Per |last5=Coutinho |first5=Alexandra |last6=Edlund |first6=Hanna |last7=Munters |first7=Arielle R. |last8=Vicente |first8=Mário |last9=Steyn |first9=Maryna |last10=Soodyall |first10=Himla |last11=Lombard |first11=Marlize |last12=Jakobsson |first12=Mattias |bibcode=2017Sci...358..652S |s2cid=206663925 |doi-access=free}}</ref><ref name="Guardian">{{cite news |url= https://www.theguardian.com/science/2017/jun/07/oldest-homo-sapiens-bones-ever-found-shake-foundations-of-the-human-story |title=Oldest ''Homo sapiens'' bones ever found shake foundations of the human story |last=Sample |first=Ian |work=[[The Guardian]] |date=June 7, 2017 |access-date=June 7, 2017 |archive-date=October 31, 2019 |archive-url= https://web.archive.org/web/20191031005024/https://www.theguardian.com/science/2017/jun/07/oldest-homo-sapiens-bones-ever-found-shake-foundations-of-the-human-story |url-status=live}}</ref> In September 2019, scientists reported the computerized determination, based on 260 [[CT scan]]s, of a virtual [[Human skull|skull shape]] of the last common human ancestor to [[modern human]]s (''H. sapiens''), representative of the earliest modern humans, and suggested that modern humans arose between 260,000 and 350,000 years ago through a merging of populations in [[East Africa|East]] and South Africa.<ref name="NYT-20190910">{{cite news |last=Zimmer |first=Carl |author-link=Carl Zimmer |title=Scientists Find the Skull of Humanity's Ancestor — on a Computer: By comparing fossils and CT scans, researchers say they have reconstructed the skull of the last common forebear of modern humans |url= https://www.nytimes.com/2019/09/10/science/human-ancestor-skull-computer.html |archive-url= https://ghostarchive.org/archive/20220101/https://www.nytimes.com/2019/09/10/science/human-ancestor-skull-computer.html |archive-date=January 1, 2022 |url-access=limited |date=September 10, 2019 |work=[[The New York Times]] |access-date=September 10, 2019}}{{cbignore}}</ref><ref name="NAT-20190910">{{cite journal |last1=Mounier |first1=Aurélien |last2=Lahr |first2=Marta |title=Deciphering African late middle Pleistocene hominin diversity and the origin of our species |journal=[[Nature Communications]] |volume=10 |issue=1 |page=3406 |doi=10.1038/s41467-019-11213-w |pmid=31506422 |pmc=6736881 |date=2019 |bibcode=2019NatCo..10.3406M}}</ref>

Between 400,000 years ago and the second interglacial period in the [[Middle Pleistocene]], around 250,000 years ago, the trend in [[Brain size#Cranial capacity|intra-cranial volume expansion]] and the elaboration of stone tool technologies developed, providing evidence for a transition from ''H.&nbsp;erectus'' to ''H.&nbsp;sapiens''. The direct evidence suggests there was a migration of ''H.&nbsp;erectus'' [[Recent African origin of modern humans|out of Africa]], then a further speciation of ''H.&nbsp;sapiens'' from ''H.&nbsp;erectus'' in Africa. A subsequent migration (both within and out of Africa) eventually replaced the earlier dispersed ''H.&nbsp;erectus''. This migration and origin theory is usually referred to as the "recent single-origin hypothesis" or "out of Africa" theory. ''H.&nbsp;sapiens'' [[Archaic human admixture with modern humans|interbred with archaic humans]] both in Africa and in Eurasia, in Eurasia notably with Neanderthals and Denisovans.<ref name="pmid21179161" /><ref name="Reich_2011" />

The [[Toba catastrophe theory]], which postulates a [[population bottleneck]] for ''H. sapiens'' about 70,000 years ago,<ref name="ambrose1998">{{cite journal |last=Ambrose |first=Stanley H. |date=June 1998 |title=Late Pleistocene human population bottlenecks, volcanic winter, and differentiation of modern humans |journal=Journal of Human Evolution |volume=34 |issue=6 |pages=623–651 |doi=10.1006/jhev.1998.0219 |issn=0047-2484 |pmid=9650103 |bibcode=1998JHumE..34..623A |s2cid=33122717}}</ref> was controversial from its first proposal in the 1990s and by the 2010s had very little support.<ref>{{Cite journal |doi=10.1073/pnas.0909000107 |ref=CITEREFHuffothers2010 |first1=Chad D. |last1=Huff |first2=Jinchuan |last2=Xing |first3=Alan R. |last3=Rogers |first4=David |last4=Witherspoon |first5=Lynn B. |last5=Jorde |title=Mobile Elements Reveal Small Population Size in the Ancient Ancestors of ''Homo sapiens'' |journal=[[Proceedings of the National Academy of Sciences of the United States of America]] |volume=107 |issue=5 |pages=2147–2152 |date=January 19, 2010 |pmc=2836654 |pmid=20133859 |url= http://www.pnas.org/content/early/2010/01/06/0909000107.full.pdf+html |bibcode=2010PNAS..107.2147H |doi-access=free}}</ref> Distinctive [[human genetic variability]] has arisen as the result of the [[founder effect]], by [[Archaic human admixture with modern humans|archaic admixture]] and by [[Recent human evolution|recent evolutionary pressures]].