Editing Human evolution (section)

== Evidence ==
The evidence on which scientific accounts of human evolution are based comes from many fields of [[natural science]]. The main source of knowledge about the evolutionary process has traditionally been the fossil record, but since the development of genetics beginning in the 1970s, DNA analysis has come to occupy a place of comparable importance. The studies of ontogeny, [[Phylogenetics|phylogeny]] and especially [[evolutionary developmental biology]] of both vertebrates and invertebrates offer considerable insight into the evolution of all life, including how humans evolved. The specific study of the origin and life of humans is [[anthropology]], particularly paleoanthropology which focuses on the study of human [[prehistory]].{{sfn|Stanford|Allen|Antón|2009}}

=== Evidence from genetics ===
{{Main|Human evolutionary genetics|Human genetic variation}}
[[File:Hominidae chart.svg|upright=1.5|thumb|Family tree showing the [[Extant taxon|extant]] hominoids: humans (genus ''[[Homo]]''), [[chimpanzee]]s and bonobos (genus ''[[Pan (genus)|Pan]]''), [[gorilla]]s (genus ''Gorilla''), [[orangutan]]s (genus ''[[Pongo (genus)|Pongo]]''), and gibbons (four genera of the family [[Hylobatidae]]: ''[[Hylobates]]'', ''[[Hoolock]]'', ''[[Nomascus]]'', and ''[[Symphalangus]]''). All except gibbons are hominids.]]

The closest living relatives of humans are bonobos and chimpanzees (both genus ''Pan'') and gorillas (genus ''Gorilla'').<ref name="Wood">{{cite journal |last1=Wood |first1=Bernard A. |last2=Richmond |first2=Brian G. |date=July 2000 |title=Human evolution: Taxonomy and paleobiology |journal=Journal of Anatomy |volume=197 |issue=1 |pages=19–60 |doi=10.1046/j.1469-7580.2000.19710019.x |issn=1469-7580 |pmid=10999270 |pmc=1468107}}</ref> With the sequencing of both the human and chimpanzee genome, {{as of|2012|lc=y}} estimates of the similarity between their DNA sequences range between 95% and 99%.<ref name="Wood" /><ref>{{cite journal |last1=Ajit |first1=Varki |author1-link=Ajit Varki |last2=Nelson |first2=David L. |date=October 2007 |title=Genomic Comparisons of Humans and Chimpanzees |journal=Annual Review of Anthropology |volume=36 |pages=191–209 |doi=10.1146/annurev.anthro.36.081406.094339 |issn=0084-6570 |url= http://www.chd.ucsd.edu/_files/fall2008/Varki.2007.ARA.pdf |access-date=April 26, 2015 |quote=Sequence differences from the human genome were confirmed to be ~1% in areas that can be precisely aligned, representing ~35 million single base-pair differences. Some 45 million nucleotides of insertions and deletions unique to each lineage were also discovered, making the actual difference between the two genomes ~4%. |archive-date=September 23, 2015 |archive-url= https://web.archive.org/web/20150923202404/http://www.chd.ucsd.edu/_files/fall2008/Varki.2007.ARA.pdf |url-status=live}}</ref><ref name="sayers">{{cite journal |last1=Sayers |first1=Ken |last2=Raghanti |first2=Mary Ann |last3=Lovejoy |first3=C. Owen |author3-link=Owen Lovejoy (anthropologist) |date=October 2012 |title=Human Evolution and the Chimpanzee Referential Doctrine |journal=Annual Review of Anthropology |volume=41 |pages=119–138 |doi=10.1146/annurev-anthro-092611-145815 |issn=0084-6570}}</ref> It is also noteworthy that mice share around 97.5% of their working DNA with humans.<ref>{{Cite web |last=#author. Coghlan |first=Andy |date=May 30, 2002 |title=Just 2.5% of DNA turns mice into men |url=https://www.newscientist.com/article/dn2352-just-2-5-of-dna-turns-mice-into-men/#:~:text=Mice%20and%20men%20share%20about%2097.5%20per,mouse-human%20differences%20as%20high%20as%2015%20per. |access-date=2024-08-18 |website=New Scientist |language=en-US}}</ref>  By using the technique called the [[molecular clock]] which estimates the time required for the number of divergent mutations to accumulate between two lineages, the approximate date for the split between lineages can be calculated.

The gibbons (family Hylobatidae) and then the orangutans (genus ''Pongo'') were the first groups to split from the line leading to the hominins, including humans—followed by gorillas (genus ''Gorilla''), and, ultimately, by the chimpanzees (genus ''Pan''). The splitting date between hominin and chimpanzee lineages is placed by some between {{Mya|4|8}}, that is, during the [[Late Miocene]].{{sfn|Dawkins|2004}}<ref>{{cite web |url= http://www.timetree.org/index.php?taxon_a=Hominidae&taxon_b=Hylobatidae&submit=Search |title=Find Time of Divergence: Hominidae versus Hylobatidae |website=[[TimeTree]] |access-date=April 18, 2015 |archive-url= https://web.archive.org/web/20150418222205/http://www.timetree.org/index.php?taxon_a=Hominidae&taxon_b=Hylobatidae&submit=Search |archive-date=April 18, 2015}}</ref><ref>{{cite journal |last=Ruvolo |first=Maryellen |date=October 1997 |title=Genetic Diversity in Hominoid Primates |journal=Annual Review of Anthropology |volume=26 |pages=515–540 |doi=10.1146/annurev.anthro.26.1.515 |issn=0084-6570}}</ref><ref name="Ruvolo1997">{{cite journal |last=Ruvolo |first=Maryellen |date=March 1997 |title=Molecular Phylogeny of the Hominoids: Inferences from Multiple Independent DNA Sequence Data Sets |journal=Molecular Biology and Evolution |volume=14 |issue=3 |pages=248–265 |doi=10.1093/oxfordjournals.molbev.a025761 |issn=0737-4038 |pmid=9066793 |doi-access=free}}</ref> Speciation, however, appears to have been unusually drawn out. Initial divergence occurred sometime between {{Mya|7|13}}, but ongoing hybridization blurred the separation and delayed complete separation during several millions of years. Patterson (2006) dated the final divergence at {{Mya|5|6}}.<ref>{{cite journal |last1=Patterson |first1=N. |last2=Richter |first2=D. J. |last3=Gnerre |first3=S. |last4=Lander |first4=E. S. |last5=Reich |first5=D. |date=2006 |title=Genetic evidence for complex speciation of humans and chimpanzees |journal=[[Nature (journal)|Nature]] |volume=441 |issue=7097 |pages=1103–1108 |doi=10.1038/nature04789 |pmid=16710306 |bibcode=2006Natur.441.1103P |s2cid=2325560}}</ref>

Genetic evidence has also been employed to compare species within the genus ''Homo'', investigating [[Archaic human admixture with modern humans|gene flow between early modern humans and Neanderthals]], and to enhance the understanding of the early human migration patterns and splitting dates. By comparing the parts of the genome that are [[Neutral theory of molecular evolution|not under natural selection]] and which therefore accumulate mutations at a fairly steady rate, it is possible to reconstruct a genetic tree incorporating the entire human species since the last shared ancestor.

Each time a certain mutation ([[single-nucleotide polymorphism]]) appears in an individual and is passed on to his or her descendants, a haplogroup is formed including all of the descendants of the individual who will also carry that mutation. By comparing mitochondrial [[DNA]] which is inherited only from the mother, geneticists have concluded that the last female common ancestor whose [[genetic marker]] is found in all modern humans, the so-called [[mitochondrial Eve]], must have lived around 200,000 years ago.

Human evolutionary genetics studies how [[human genome]]s differ among individuals, the evolutionary past that gave rise to them, and their current effects. Differences between genomes have [[Anthropology|anthropological]], medical and [[Forensic science|forensic]] implications and applications. Genetic data can provide important insight into human evolution.

In May 2023, scientists reported a more complicated pathway of human evolution than previously understood. According to the studies, humans evolved from different places and times in Africa, instead of from a single location and period of time.<ref name="NYT-20230517">{{cite news |last=Zimmer |first=Carl |author-link=Carl Zimmer |title=Study Offers New Twist in How the First Humans Evolved - A new genetic analysis of 290 people suggests that humans emerged at various times and places in Africa. |url= https://www.nytimes.com/2023/05/17/science/human-origins-africa.html |date=May 17, 2023 |work=[[The New York Times]] |archive-url= https://archive.today/20230517235653/https://www.nytimes.com/2023/05/17/science/human-origins-africa.html |archive-date=May 17, 2023 |access-date=May 18, 2023}}</ref><ref name="NAT-20230517">{{cite journal |last1=Ragsdale |first1=Aaron P. |display-authors=et al. |title=A weakly structured stem for human origins in Africa |date=May 17, 2023 |journal=[[Nature (journal)|Nature]] |volume=167 |issue=7962 |pages=755–763 |doi=10.1038/s41586-023-06055-y |pmid=37198480 |pmc=10208968 |bibcode=2023Natur.617..755R}}</ref>

=== Evidence from the fossil record ===
[[File:Homo habilis-KNM ER 1813.jpg|thumb|upright|Replica of fossil skull of ''[[H.&nbsp;habilis]]''. Fossil number KNM ER 1813, found at [[Koobi Fora]], Kenya.]]
[[File:Homo ergaster.jpg|thumb|upright|Replica of fossil skull of ''[[H.&nbsp;ergaster]]'' (African ''H.&nbsp;erectus''). Fossil number Khm-Heu 3733 discovered in 1975 in Kenya.]]

There is little fossil evidence for the divergence of the gorilla, chimpanzee and hominin lineages.<ref>{{cite journal |last=Begun |first=David R. |date=October 2010 |title=Miocene Hominids and the Origins of the African Apes and Humans |journal=Annual Review of Anthropology |volume=39 |pages=67–84 |doi=10.1146/annurev.anthro.012809.105047 |issn=0084-6570}}</ref> The earliest fossils that have been proposed as members of the hominin lineage are ''Sahelanthropus tchadensis'' dating from {{mya|7}}, ''Orrorin tugenensis'' dating from {{mya|5.7}}, and ''Ardipithecus kadabba'' dating to {{mya|5.6}}. Each of these have been argued to be a [[bipedal]] ancestor of later hominins but, in each case, the claims have been contested. It is also possible that one or more of these species are ancestors of another branch of African apes, or that they represent a shared ancestor between hominins and other apes.

The question then of the relationship between these early fossil species and the hominin lineage is still to be resolved. From these early species, the australopithecines arose around {{mya|4}} and diverged into [[Paranthropus|robust]] (also called ''[[Paranthropus]]'') and [[Australopithecus|gracile]] branches, one of which (possibly ''[[Australopithecus garhi|A. garhi]]'') probably went on to become ancestors of the genus ''Homo''. The australopithecine species that is best represented in the fossil record is ''Australopithecus afarensis'' with more than 100 fossil individuals represented, found from Northern Ethiopia (such as the famous "Lucy"), to Kenya, and South Africa. Fossils of robust australopithecines such as ''A. robustus'' (or alternatively ''[[Paranthropus robustus]]'') and ''A./P. boisei'' are particularly abundant in South Africa at sites such as [[Kromdraai]] and [[Swartkrans]], and around [[Lake Turkana]] in Kenya.

The earliest member of the genus ''Homo'' is ''Homo habilis'' which evolved around {{Mya|2.8}}.<ref name="autogenerated1" /> ''H.&nbsp;habilis'' is the first species for which we have positive evidence of the use of stone tools. They developed the [[Oldowan]] lithic technology, named after the Olduvai Gorge in which the first specimens were found. Some scientists consider ''[[Homo rudolfensis]]'', a larger bodied group of fossils with similar morphology to the original ''H.&nbsp;habilis'' fossils, to be a separate species, while others consider them to be part of ''H.&nbsp;habilis''—simply representing intraspecies variation, or perhaps even [[sexual dimorphism]]. The brains of these early hominins were about the same size as that of a chimpanzee, and their main adaptation was bipedalism as an adaptation to terrestrial living.

During the next million years, a process of encephalization began and, by the arrival (about {{Mya|1.9}}) of ''H.&nbsp;erectus'' in the fossil record, cranial capacity had doubled. ''H.&nbsp;erectus'' were the first of the hominins to emigrate from Africa, and, from {{Mya|1.8|1.3}}, this species spread through Africa, Asia, and Europe. One population of ''H.&nbsp;erectus'', also sometimes classified as separate species ''H.&nbsp;ergaster'', remained in Africa and evolved into ''H.&nbsp;sapiens''. It is believed that ''H.&nbsp;erectus'' and ''H.&nbsp;ergaster'' were the first to use fire and complex tools. In Eurasia, ''H.&nbsp;erectus'' evolved into species such as ''[[H.&nbsp;antecessor]]'', ''[[H.&nbsp;heidelbergensis]]'' and ''[[H.&nbsp;neanderthalensis]]''. The earliest fossils of anatomically modern humans are from the Middle Paleolithic, about 300–200,000 years ago such as the Herto and [[Omo remains]] of Ethiopia, [[Jebel Irhoud]] remains of Morocco, and Florisbad remains of South Africa; [[Skhul and Qafzeh hominins|later fossils]] from the [[Skhul Cave]] in Israel and Southern Europe begin around 90,000 years ago ({{Mya|0.09}}).

As modern humans spread out from Africa, they encountered other hominins such as ''H.&nbsp;neanderthalensis'' and the Denisovans, who may have evolved from populations of ''H.&nbsp;erectus'' that had left Africa around {{mya|2}}. The nature of interaction between early humans and these sister species has been a long-standing source of controversy, the question being whether humans replaced these earlier species or whether they were in fact similar enough to interbreed, in which case these earlier populations may have contributed genetic material to modern humans.{{sfn|Wood|2009|pp=[https://link.springer.com/chapter/10.1007%2F978-1-4020-9980-9_3#page-1 17–27]}}<ref name="NYT-01302012">{{cite news |last=Mitchell |first=Alanna |date=January 30, 2012 |title=DNA Turning Human Story Into a Tell-All |url= https://www.nytimes.com/2012/01/31/science/gains-in-dna-are-speeding-research-into-human-origins.html |archive-url= https://ghostarchive.org/archive/20220101/https://www.nytimes.com/2012/01/31/science/gains-in-dna-are-speeding-research-into-human-origins.html |archive-date=January 1, 2022 |url-access=limited |newspaper=The New York Times |access-date=February 13, 2012}}{{cbignore}}</ref>

This migration out of Africa is estimated to have begun about 70–50,000 years [[Before Present|BP]] and modern humans subsequently spread globally, replacing earlier hominins either through competition or hybridization. They inhabited Eurasia and Oceania by 40,000 years BP, and the Americas by at least 14,500 years BP.<ref>{{cite journal |last=Wood |first=Bernard A. |date=December 1996 |title=Human evolution |journal=BioEssays |volume=18 |issue=12 |pages=945–954 |doi=10.1002/bies.950181204 |issn=0265-9247 |pmid=8976151 |s2cid=221464189}}</ref>

=== Inter-species breeding ===
{{Further|Interbreeding between archaic and modern humans}}
[[File:Homo lineage 2017update.svg|thumb|upright=1.35|A model of the evolution of the genus ''Homo'' over the last 2&nbsp;million years (vertical axis). The rapid "[[Recent African origin of modern humans|Out of Africa]]" expansion of ''H. sapiens'' is indicated at the top of the diagram, with admixture indicated with [[Neanderthals]], [[Denisovans]], and unspecified archaic African hominins.]]
The hypothesis of interbreeding, also known as hybridization, admixture or hybrid-origin theory, has been discussed ever since the discovery of Neanderthal remains in the 19th century.<ref>{{cite book |last=Huxley |first=T. |title=Collected Essays: Volume VII, Man's Place in Nature |date=1890 |chapter=The Aryan Question and Pre-Historic Man |chapter-url= http://aleph0.clarku.edu/huxley/CE7/Aryan.html |access-date=August 25, 2018 |archive-date=July 26, 2011 |archive-url= https://web.archive.org/web/20110726231311/http://aleph0.clarku.edu/huxley/CE7/Aryan.html |url-status=live}}</ref> The linear view of human evolution began to be abandoned in the 1970s as different species of humans were discovered that made the linear concept increasingly unlikely. In the 21st century with the advent of molecular biology techniques and computerization, [[whole-genome sequencing]] of Neanderthal and human [[genome]] were performed, confirming recent admixture between different human species.<ref name="greenetal" /> In 2010, evidence based on molecular biology was published, revealing unambiguous examples of interbreeding between archaic and modern humans during the [[Middle Paleolithic]] and early [[Upper Paleolithic]]. It has been demonstrated that interbreeding happened in several independent events that included Neanderthals and Denisovans, as well as several unidentified hominins.<ref>{{cite web |last=Coghlan |first=Andy |date=March 15, 2018 |url= https://www.newscientist.com/article/2163910-our-ancestors-mated-with-the-mystery-denisovan-people-twice/ |title=Our ancestors mated with the mystery 'Denisovan' people – twice |work=[[New Scientist]] |access-date=August 25, 2018 |url-status=live |archive-url= https://web.archive.org/web/20180805035916/https://www.newscientist.com/article/2163910-our-ancestors-mated-with-the-mystery-denisovan-people-twice |archive-date=August 5, 2018}}</ref> Today, approximately 2% of DNA from all non-African populations (including Europeans, Asians, and [[Oceanians]]) is Neanderthal,<ref name="greenetal" /> with traces of Denisovan heritage.<ref name="NG-20180822">{{cite news |last=Wei-Haas |first=Maya |date=August 22, 2018 |title=Ancient Girl's Parents Were Two Different Human Species – Born 90,000 years ago, the child is the first direct evidence of interbreeding among Neanderthals and their cousins the Denisovans |work=National Geographic |url= https://www.nationalgeographic.com/science/2018/08/news-denisovan-neanderthal-hominin-hybrid-ancient-human/ |access-date=August 22, 2018 |archive-date=June 14, 2019 |archive-url= https://web.archive.org/web/20190614092015/https://www.nationalgeographic.com/science/2018/08/news-denisovan-neanderthal-hominin-hybrid-ancient-human/ |url-status=dead}}</ref> Also, 4–6% of modern [[Melanesians|Melanesian]] genetics are Denisovan.<ref name="NG-20180822" /> Comparisons of the human genome to the genomes of Neandertals, Denisovans and apes can help identify features that set modern humans apart from other hominin species. In a 2016 [[comparative genomics]] study, a Harvard Medical School/UCLA research team made a world map on the distribution and made some predictions about where Denisovan and Neanderthal genes may be impacting modern human biology.<ref>{{cite web |url= https://www.sciencedaily.com/releases/2016/03/160328133514.htm |author=Cell Press |author-link=Cell Press |title=A world map of Neanderthal and Denisovan ancestry in modern humans |date=March 28, 2016 |website=ScienceDaily |access-date=August 25, 2018 |archive-date=August 26, 2018 |archive-url= https://web.archive.org/web/20180826005214/https://www.sciencedaily.com/releases/2016/03/160328133514.htm |url-status=live}}</ref><ref>{{cite journal |last1=Sankararaman |first1=S. |last2=Mallick |first2=S. |last3=Patterson |first3=N. |last4=Reich |first4=D. |date=March 28, 2016 |title=The Combined Landscape of Denisovan and Neanderthal Ancestry in Present-Day Humans |journal=Current Biology |volume=26 |issue=9 |pages=1241–1247 |doi=10.1016/j.cub.2016.03.037 |pmid=27032491 |pmc=4864120 |bibcode=2016CBio...26.1241S}}</ref>

For example, comparative studies in the mid-2010s found several [[Phenotypic trait|traits]] related to neurological, immunological,<ref>{{cite web |publisher=American Association for the Advancement of Science |work=the Neandertal Genome |url= http://www.sciencemag.org/site/special/neandertal/feature/genomics.html |title=Human-Neandertal Comparisons |date=2010 |archive-url= https://web.archive.org/web/20200528032345/http://www.sciencemag.org/site/special/neandertal/feature/genomics.html |archive-date=May 28, 2020}}</ref> developmental, and metabolic phenotypes, that were developed by archaic humans to European and Asian environments and inherited to modern humans through admixture with local hominins.<ref>{{cite journal |last1=Dannemann |first1=M. |last2=Andrés |first2=A. M. |last3=Kelso |first3=J. |title=Introgression of Neandertal- and Denisovan-like Haplotypes Contributes to Adaptive Variation in Human Toll-like Receptors |date=2016 |journal=[[American Journal of Human Genetics]] |volume=98 |issue=1 |pages=22–33 |doi=10.1016/j.ajhg.2015.11.015 |pmid=26748514 |pmc=4716682}}</ref><ref>{{cite journal |last1=Gittelman |first1=Rachel M. |last2=Schraiber |first2=Joshua G. |last3=Vernot |first3=Benjamin |last4=Mikacenic |first4=Carmen |last5=Wurfel |first5=Mark M. |last6=Akey |first6=Joshua M. |date=2016 |title=Archaic Hominin Admixture Facilitated Adaptation to Out-of-Africa Environments |journal=[[Current Biology]] |volume=26 |issue=24 |pages=3375–3382 |doi=10.1016/j.cub.2016.10.041 |pmid=27839976 |pmc=6764441 |bibcode=2016CBio...26.3375G}}</ref>

Although the narratives of human evolution are often contentious, several discoveries since 2010 show that human evolution should not be seen as a simple linear or branched progression, but a mix of related species.<ref name="pmid21179161" /><ref name="Denisovans & Neandertals" /><ref name="Human Hybrids" /><ref name="Mosaic humans, the hybrid species" /> In fact, genomic research has shown that hybridization between substantially diverged lineages is the rule, not the exception, in human evolution.<ref name="Ackermann 2015">{{cite journal |title=The Hybrid Origin of "Modern" Humans |first1=Rebecca |last1=Rogers Ackermann |first2=Alex |last2=Mackay |first3=Michael L. |last3=Arnold |journal=Evolutionary Biology |date=October 2015 |doi=10.1007/s11692-015-9348-1 |volume=43 |issue=1 |pages=1–11 |s2cid=14329491}}</ref> Furthermore, it is argued that hybridization was an essential creative force in the emergence of modern humans.<ref name="Ackermann 2015" />

=== Stone tools ===
{{Main|Stone tool}}
Stone tools are first attested around 2.6&nbsp;million years ago, when hominins in Eastern Africa used so-called core [[Oldowan|tools]], [[Chopper (archaeology)|choppers]] made out of round cores that had been split by simple strikes.<ref name="Plummer">{{cite journal |last=Plummer |first=Thomas |date=2004 |title=Flaked stones and old bones: Biological and cultural evolution at the dawn of technology |journal=American Journal of Physical Anthropology |volume=125 |issue=Supplement 39: Yearbook of Physical Anthropology |pages=118–164 |doi=10.1002/ajpa.20157 |issn=0002-9483 |pmid=15605391 |doi-access=free}}</ref> This marks the beginning of the [[Paleolithic]], or Old [[Stone Age]]; its end is taken to be the end of the last [[Last glacial period|Ice Age]], around 10,000 years ago. The Paleolithic is subdivided into the [[Lower Paleolithic]] (Early Stone Age), ending around 350,000–300,000 years ago, the [[Middle Paleolithic]] (Middle Stone Age), until 50,000–30,000 years ago, and the [[Upper Paleolithic]], (Late Stone Age), 50,000–10,000 years ago.

Archaeologists working in the Great Rift Valley in Kenya have discovered the oldest known stone tools in the world. Dated to around 3.3&nbsp;million years ago, the implements are some 700,000 years older than stone tools from Ethiopia that previously held this distinction.<ref name="Harmand 310–315" /><ref>{{cite journal |last=Wong |first=Kate |date=April 15, 2015 |title=Archaeologists Take Wrong Turn, Find World's Oldest Stone Tools |url= http://blogs.scientificamerican.com/observations/2015/04/15/archaeologists-take-wrong-turn-find-worlds-oldest-stone-tools/ |journal=Scientific American |type=Blog |issn=0036-8733 |access-date=May 3, 2015 |archive-date=May 8, 2015 |archive-url= https://web.archive.org/web/20150508034444/http://blogs.scientificamerican.com/observations/2015/04/15/archaeologists-take-wrong-turn-find-worlds-oldest-stone-tools/ |url-status=live}}</ref><ref>{{cite journal |last=Balter |first=Michael |date=April 14, 2015 |title=World's oldest stone tools discovered in Kenya |url= https://www.science.org/content/article/world-s-oldest-stone-tools-discovered-kenya |journal=[[Science (journal)|Science]] |type=News |doi=10.1126/science.aab2487 |issn=0036-8075 |access-date=May 3, 2015 |archive-date=October 20, 2021 |archive-url= https://web.archive.org/web/20211020055503/https://www.science.org/content/article/world-s-oldest-stone-tools-discovered-kenya |url-status=live}}</ref><ref>{{cite news |last=Drake |first=Nadia |author-link=Nadia Drake |date=April 16, 2015 |title=Oldest Stone Tools Discovered in Kenya |url= http://news.nationalgeographic.com/2015/04/150416-oil-fish-hearts-spill-tuna-gulf-bp-deepwater-exxon-alaska/150416-oldest-stone-tools-archaeology-kenya-human-origins-evolution/ |work=National Geographic News |location=Washington, DC |publisher=[[National Geographic Society]] |access-date=May 3, 2015 |archive-date=April 23, 2015 |archive-url= https://web.archive.org/web/20150423222706/http://news.nationalgeographic.com/2015/04/150416-oil-fish-hearts-spill-tuna-gulf-bp-deepwater-exxon-alaska/150416-oldest-stone-tools-archaeology-kenya-human-origins-evolution/ |url-status=dead}}</ref>

The period from 700,000 to 300,000 years ago is also known as the [[Acheulean]], when ''H.&nbsp;ergaster'' (or ''erectus'') made large stone [[hand axe]]s out of [[flint]] and [[quartzite]], at first quite rough (Early Acheulian), later "[[retouch (lithics)|retouched]]" by additional, more-subtle strikes at the sides of the [[Lithic flake|flakes]]. After 350,000 BP the more refined so-called [[Levallois technique]] was developed, a series of consecutive strikes, by which scrapers, slicers ("racloirs"), needles, and flattened needles were made.<ref name="Plummer" /> Finally, after about 50,000 BP, ever more refined and specialized flint tools were made by the Neanderthals and the immigrant [[Cro-Magnon]]s (knives, blades, skimmers). Bone tools were also made by ''H. sapiens'' in Africa by 90,000–70,000 years ago<ref name="Henshilwood etal 2002">{{cite journal |last1=Henshilwood |first1=C. S. |last2=d'Errico |first2=F. |last3=Yates |first3=R. |last4=Jacobs |first4=Z. |last5=Tribolo |first5=C. |last6=Duller |first6=G. A. T. |last7=Mercier |first7=N. |last8=Sealy |first8=J. C. |last9=Valladas |first9=H. |last10=Watts |first10=I. |last11=Wintle |first11=A. G. |author-link=Christopher Henshilwood |display-authors=3 |date=2002 |title=Emergence of Modern Human Behavior: Middle Stone Age Engravings from South Africa |journal=[[Science (journal)|Science]] |volume=295 |issue=5558 |pages=1278–1280 |doi=10.1126/science.1067575 |pmid=11786608 |s2cid=31169551 |bibcode=2002Sci...295.1278H}}</ref><ref>{{cite journal |title=A middle stone age worked bone industry from Katanda, Upper Semliki Valley, Zaire |date=April 28, 1995 |last1=Yellen |first1=J. E. |last2=Brooks |first2=A. S. |last3=Cornelissen |first3=E. |last4=Mehlman |first4=M. J. |last5=Stewart |first5=K. |journal=[[Science (journal)|Science]] |volume=268 |pages=553–556 |issue=5210 |doi=10.1126/science.7725100 |pmid=7725100 |bibcode=1995Sci...268..553Y}}</ref> and are also known from early ''H. sapiens'' sites in Eurasia by about 50,000 years ago.