ergaster

Skull III, discovered at Locus E in 1929 is an adolescent or juvenile with a brain size of 915 cc.

Skull II, discovered at Locus D in 1929 but only recognized in 1930, is an adult or adolescent with a brain size of 1030 cc.

Skulls X, XI and XII (sometimes called LI, LII and LIII) were discovered at Locus L in 1936. They are thought to belong to an adult man, an adult woman and a young adult, with brain sizes of 1225 cc, 1015 cc and 1030 cc respectively. (Weidenreich 1937)

Skull V: two cranial fragments were discovered in 1966 which fit with (casts of) two other fragments found in 1934 and 1936 to form much of a skullcap with a brain size of 1140 cc. These pieces were found at a higher level, and appear to be more modern than the other skullcaps. (Jia and Huang 1990) (Creationist arguments)

Most of the study on these fossils was done by Davidson Black until his death in 1934. Franz Weidenreich replaced him and studied the fossils until leaving China in 1941. The original fossils disappeared in 1941 while being shipped to the United States for safety during World War II, but excellent casts and descriptions remain. Since the war, other erectus fossils have been found at this site and others in China.

The illustration above is of a reconstruction done by Franz Weidenreich, based on bones from at least four different individuals (none of the fossils were this complete).

and American palaeontologist Walter W. Granger came to Zhoukoudian, China in search of prehistoric fossils in 1921. They were directed to the site at Dragon Bone Hill by local quarrymen, where Andersson recognised deposits of quartz that were not native to the area. Immediately realising the importance of this find he turned to his colleague and announced, "Here is primitive man, now all we have to do is find him!"

Excavation work was begun immediately by Andersson's assistant Austrian palaeontologist Otto Zdansky, who found what appeared to be a fossilised human molar. He returned to the site in 1923 and materials excavated in the two subsequent digs were sent back to Uppsala University in Sweden for analysis. In 1926 Andersson announced the discovery of two human molars found in this material and Zdansky published his findings.

Canadian anatomist Davidson Black of Peking Union Medical College, excited by Andersson and Zdansky’s find, secured funding from the Rockefeller Foundation and recommenced excavations at the site in 1927 with both Western and Chinese scientists. A tooth was unearthed that fall by Swedish palaeontologist Anders Birger Bohlin which Davidson placed in a locket around his neck.

Davidson published his analysis in the journal Nature, identifying his find as belonging to a new species and genus which he named Sinanthropus pekinensis, but many fellow scientists were skeptical of such an identification based on a single tooth and the Foundation demanded more specimens before they would give an additional grant.

A lower jaw, several teeth, and skull fragments were unearthed in 1928. Black presented these finds to the Foundation and was rewarded with an $80,000 grant that he used to establish the Cenozoic Research Laboratory.

Excavations at the site under the supervision of Chinese archaeologists Yang Zhongjian, Pei Wenzhong, and Jia Lanpo uncovered 200 human fossils (including 6 nearly complete skullcaps) from more than 40 individual specimens. These excavation came to an end in 1937 with the Japanese invasion.

Fossils of Peking Man were placed in the safe at the Cenozoic Research Laboratory of the Peking Union Medical College. Eventually, in November 1941, secretary Hu Chengzi packed up the fossils so they could be sent to USA for safekeeping until the end of the war. They vanished en route to the port city of Qinhuangdao.

Various parties have tried to locate the fossils, but so far they have been without result. In 1972, a US financier Christopher Janus promised a $5,000 (USD) reward for the missing skulls; one woman contacted him, asking for $500,000 (USD) but she later vanished. In July 2005, the Chinese government founded a committee to find the bones to coincide with the 60th anniversary of the end of World War II.

There are various theories of what might have happened, including a theory that the bones sank with the Japanese ship Awa Maru in 1945. Three of the teeth can, however, be found at the Paleontological Museum of Uppsala University.

Excavations at Zhoukoudian resumed after the war, and parts of another skull were found in 1966. To date a number of other partial fossil remains have been found. The Peking Man Site at Zhoukoudian was listed by UNESCO as a World Heritage Site in 1987. New excavations were scheduled to start at the site in the middle of May 2009.

The first specimens of Homo erectus had been found in Java in 1891 by Eugene Dubois, but were dismissed by many as the remains of a deformed ape. The discovery of the great quantity of finds at Zhoukoudian put this to rest and Java Man, who had initially been named Pithecanthropus erectus, was transferred to the genus Homo along with Peking Man.

Contiguous findings of animal remains and evidence of fire and tool usage, as well as the manufacturing of tools, were used to support H. erectus being the first "faber" or tool-worker. The analysis of the remains of "Peking Man" led to the claim that the Zhoukoudian and Java fossils were examples of the same broad stage of human evolution.

This interpretation was challenged in 1985 by Lewis Binford, who claimed that the Peking Man was a scavenger, not a hunter. The 1998 team of Steve Weiner of the Weizmann Institute of Science concluded that they had not found evidence that the Peking Man had used fire

Some Chinese paleoanthropologists[who?] have asserted in the past that the modern Chinese (and possibly other ethnic groups) are descendants of Peking Man. However, a recent study undertaken by Chinese geneticist Jin Li showed that the genetic diversity of modern Chinese people is well within that of the whole world population, which suggests there was no inter-breeding between modern human immigrants to East Asia and Homo erectus, such as Peking Man, and that the Chinese are descended from Africa, like all other modern humans, in accordance with the Recent single-origin hypothesis, the consensus among most modern scientists. However, the RRM2P4 gene data suggests that the Chinese, while largely descending from Africa like all other humans, nevertheless have some genetic legacy from hybridization with older Eurasian populations, consistent with limited multiregional evolution. Some paleontologists claim to see continuity in skeletal remains.

Homo antecessor is an extinct human species (or subspecies) dating from 1.2 million to 800,000 years ago, that was discovered by Eudald Carbonell, J. L. Arsuaga and J. M. Bermúdez de Castro. H. antecessor is one of the earliest known human varieties in Europe. Many anthropologists believe that H. antecessor is either the same species or a direct antecedent to Homo heidelbergensis, who inhabited Europe from 600,000 to 250,000 years ago in the Pleistocene.

The best-preserved fossil is a maxilla which belonged to a 10-year-old individual found in Spain. Based on palaeomagnetic measurements, it is thought to be older than 780-857 ka (Falguères et al., 1999:351). The average brain was 1000 cm³ in volume. In 1994 and 1995, 80 fossils of six individuals that may have belonged to the species were found in Atapuerca, Spain. At the site were numerous examples of cuts where the flesh had been flensed from the bones, which indicates that H. antecessor could have practised cannibalism.

Homo antecessor was about 1.6-1.8 m (5½-6 feet) tall, and males weighed roughly 90 kg (200 pounds). Their brain sizes were roughly 1000–1150 cm³, smaller than the 1350 cm³ average of modern humans. Due to its scarcity, very little more is known about the physiology of H. antecessor, yet it was likely to have been more robust than H. heidelbergensis. According to Juan Luis Arsuaga, one of the co-directors of the excavation in Burgos, H. antecessor might have been right-handed, a trait that makes them different from the other apes. The hypothesis is based on tomography techniques. Arsuaga also claims that the frequency range of audition is similar to H. sapiens' which makes him believe that H. antecessor used a symbolic language and was able to reason. Arsuaga's team is currently pursuing a DNA map of H. antecessor after elucidating that of a bear that lived in northern Spain some 500,000 years ago.

Basing on teeth eruption pattern, the researchers think that Homo antecessor had the same development stages as Homo sapiens, though probably at a faster pace. Other features acquired by the species are a protruding occipital bun, a low forehead and a lack of a strong chin. Some of the remains are almost indistinguishable from the fossil attributable to KNM-WT 15000 (Turkana Boy) belonging to Homo ergaster

The only known fossils of H. antecessor are from two sites in the Sierra de Atapuerca region of northern Spain (Gran Dolina and Sima del Elefante).

Archaeologist Eudald Carbonell i Roura of the Universidad Rovira i Virgili in Tarragona, Spain and palaeoanthropologist Juan Luis Arsuaga Ferreras of the Complutense University of Madrid discovered Homo antecessor remains at the Gran Dolina site in the Sierra de Atapuerca, east of Burgos. The H. antecessor remains have been found in level 6 (TF6) of the Gran Dolina site. Over 80 bone fragments from six individuals were uncovered in 1994 and 1995. The site had also included roughly 200 stone tools and about 300 animal bones. Stone tools including a stone carved knife were found along with the ancient hominin remains. All these remains were dated at least 780,000 years old. The best-preserved remains are a maxilla (upper jawbone) and a frontal bone of an individual who died at 10–11 years old.

On 29 June 2007, Spanish researchers working at the Sima del Elefante site announced that they had recovered a molar dated to 1.1–1.2 million years ago. The molar was described as "well worn" and from an individual between 20 and 25 years of age. Additional findings announced on 27 March 2008 included the discovery of a mandible fragment, stone flakes, and evidence of animal bone processing.

Homo ergaster is an extinct chronospecies of Homo that lived in eastern and southern Africa from the end of the Pliocene epoch to the early Pleistocene, about 1.8-1.3 million years ago. There is still disagreement on the subject of the classification, ancestry, and progeny of H. ergaster, but it is now widely thought (though not agreed) to be the direct ancestor of later hominids such as Homo heidelbergensis, Homo sapiens and Homo neanderthalensis rather than Asian Homo erectus. It is one of the earliest members of the genus Homo, possibly descended from, or sharing a common ancestor with, Homo habilis.

The binominal name published in 1975 by Groves and Mazák is derived from the Greek εργαστηρ "workman", in reference to the comparatively advanced lithic technology developed by the species, introducing the Acheulean industry.

S.A paleontologist John Robinson first discovered a mandible of a new hominid in southern Africa in 1949; he named the species Telanthropus capensis, though it is now recognised as a member of Homo ergaster. The name was first applied by Colin Groves and Vratislav Mazák to KNM-ER 992, a mandible discovered near Lake Rudolf (now Lake Turkana), Kenya in 1975, which became the type-specimen of the species. The most complete skeleton of H. ergaster (and one of the most complete extinct hominids to date), KNM-WT 15000, was discovered at Lake Turkana, Kenya, in 1984 by paleoanthropologists Kamoya Kimeu and Alan Walker. They nicknamed the 1.6-million-year-old specimen "Turkana Boy".

Many paleoanthropologists still debate the definition of H. ergaster and H. erectus as separate species. Some call H. ergaster the direct African ancestor of H. erectus, proposing that H. ergaster emigrated out of Africa and into Asia, branching into a distinct species. Most dispense with the species-name ergaster, making no distinction between such fossils as the Turkana Boy and Peking Man. Though "Homo ergaster" has gained some acceptance as a valid taxon, H. ergaster and H. erectus are still usually defined as distinct African and Asian populations of the larger species H. erectus. (For the remainder of this article, the name "Homo ergaster"will be used to describe a distinct species for the convenience of continuity in reading.)

H. ergaster may be distinguished from H. erectus by its thinner skull-bones and lack of an obvious supraorbital sulcus. It may be distinguished from Homo heidelbergensis by its thinner bones, more protrusive face, and lower forehead. Derived features separating it from earlier species include reduced sexual dimorphism, a smaller, more orthognathous (less protrusive) face, a smaller dental arcade, and a larger cranial capacity (700-900cm³ in earlier ergaster-specimens, and 900-1100 in later specimens). It is estimated that H. ergaster stood at 1.9 metres (6.2 ft) tall. Remains have been found in Tanzania, Ethiopia, Kenya, and South Africa.

is generally accepted as the putative ancestor of the genus Homo, and often of H. ergaster most directly. This taxon's status as a legitimate species within "Homo", however, is particularly contentious. H. habilis and H. ergaster coexisted for 200,000-300,000 years, possibly indicating that these species diverged from a common ancestor. It is unclear the genetic influence that H. ergaster had on later hominids. Recent genetic analysis has generally supported the Out-of-Africa hypothesis, and this may designate H. ergaster the role of ancestor to all later hominids

H. ergaster diverged from the lineage of H. habilis between 1.9 and 1.8 million years ago; the lineage that emigrated Africa and fathered H. erectus diverged from the lineage of H. ergaster almost immediately after this. These early descendants of H. ergaster may have been discovered in Dmanisi, Georgia.H. ergaster remained stable for ca. 500,000 years in Africa before disappearing from the fossil record around 1.4 million years ago. No identifiable cause has been attributed to this disappearance; the later evolution of the similar H. heidelbergensis in Africa may indicate that this is simply a hole in the record, or that some intermediate species has not yet been discovered.

Homo ergaster used more diverse and sophisticated stone tools than its predecessors: H. erectus. H. ergaster refined the inherited Oldowan developing the first Acheulean bifacial axes: while the use of Acheulean tools began ca. 1.6 million years ago, the line of H. erectus diverged some 200,000 years before the general innovation of Acheulean technology. Thus the Asian migratory descendants of H. ergaster made no use of any Acheulean technology.

Sexual dimorphism in H. ergaster is greatly reduced from its australopithecine ancestors (around 20%), but still greater than dimorphism in modern humans. This diminished competition for mates between males, implied by the reduction in sexual dimorphism, may also correspond to the more modern social practices of ergaster. Not only was H. ergaster like modern humans in body, but also more in organisation and sociality than any earlier species. It is conceivable that H. ergaster was the first hominin to harness fire: whether as the containment of natural fire, or as the lighting of artificial fire, is still a matter of contention. It is now assumed, however, that erectus did have control of fire, as well as each other hominin sharing a common ancestor with ergaster. The social organisation of H. ergaster probably resembled that of modern hunter-gatherer societies. Unlike australopithecines, ergaster males presumably did not compete at all for females, which had themselves increased in size greatly in proportion to males. This reduced competition and dimorphism also coincided with an increase in brain size and efficiency of stone tools.

Homo ergaster was probably the first hominid to "use a human voice",clarification needed] though its symbolic cognition was probably somewhat more[clarification needed] limited. It was thought for a long time that H. ergaster was restricted in the physical ability to regulate breathing and produce complex sounds. This was based on Turkana Boy's cervical vertebrae, which were far narrower than in later humans. Discoveries of cervical vertebrae in Dmanisi, Georgia some .3 million years older than those of Turkana Boy are well within the normal human range. It has been established, furthermore, that the Turkana Boy probably suffered from a disease of the spinal column that resulted in narrower cervical vertebrae than in modern humans (as well as the older Dmanisi finds). While the Dmanisi finds have not been established definitively as H. ergaster; they are older than Turkana Boy (the only definite ergaster-vertebrae on record), and thereby suggest kinship to ergaster. Turkana Boy, therefore, may be an anomaly.

There is no archaeological evidence that Homo ergaster made use of symbolic thought (such as figurative art), but the well evolved brain and physical capabilities (along with reconfiguration of ergaster's breathing-apparatus) suggest some form of linguistic or symbolic communication.

Homo is the genus that includes modern humans and species closely related to them. The genus is estimated to be about 2.3 to 2.4 million years old,evolving from australopithecine ancestors with the appearance of Homo habilis. Specifically, H. habilis is assumed to be the direct descendant of Australopithecus garhi which lived about 2.5 million years ago. The most salient physiological development between the two species is the increase in cranial capacity, from about 450 ccm in A. garhi to 600 ccm in H. habilis. Within the Homo genus, cranial capacity again doubled from H. habilis to H. heidelbergensis by 0.6 million years ago. The cranial capacity of H. heidelbergensis overlaps with the range found in modern humans.

The advent of Homo coincides with the first evidence of stone tools (the Oldowan industry), and thus by definition with the beginning of the Lower Paleolithic. The emergence of Homo also coincides roughly with the onset of Quaternary glaciation, the beginning of the current ice age.

All species of the genus except Homo sapiens (modern humans) are extinct. Homo neanderthalensis, traditionally considered the last surviving relative, died out 24,000 years ago, while a recent discovery suggests that another species, Homo floresiensis, discovered in 2003, may have lived as recently as 12,000 years ago. The discovery of Denisova hominin, announced in March 2010, may reveal it to be yet another species in the genus.

In biological sciences, particularly anthropology and paleontology, the common name for all members of the genus Homo is "human."

The word homo is Latin, in the original sense of "human being", or "man" (in the gender-neutral sense). The word "human" itself is from Latin humanus, an adjective cognate to homo, both thought to derive from a Proto-Indo-European word for "earth" reconstructed as *dhǵhem-.

The binominal name Homo sapiens is due to Linnaeus (1758). Names for other species are coined beginning in the second half of the 19th century (H. neanderthalensis 1864, H. erectus 1892).

Species status of Homo rudolfensis, H. ergaster, H. georgicus, H. antecessor, H. cepranensis, H. rhodesiensis and H. floresiensis remains under debate. H. heidelbergensis and H. neanderthalensis are closely related to each other and have been considered to be subspecies of H. sapiens. Recently, nuclear DNA from a Neanderthal specimen from Vindija has been sequenced as well, using two different methods that yield similar results regarding Neanderthal and H. sapiens lineages, with both analyses suggesting a date for the split between 460,000 and 700,000 years ago, though a population split of around 370,000 years is inferred. The nuclear DNA results indicate that about 30% of derived alleles in H. sapiens are also in the Neanderthal lineage. This high frequency may suggest some gene flow between ancestral humans and Neanderthal populations.

Humans commonly refers to the species Homo sapiens (Latin: "wise man" or "knowing man"), the only extant member of the Homo genus of bipedal primates in Hominidae, the great ape family. However, in some cases the term is used to refer to any member of the genus Homo.

Humans have a highly developed brain, capable of abstract reasoning, language, introspection, and problem solving. This mental capability, combined with an erect body carriage that frees the hands for manipulating objects, has allowed humans to make far greater use of tools than any other species. Mitochondrial DNA and fossil evidence indicates that modern humans originated in Africa about 200,000 years ago. With individuals widespread in every continent except Antarctica, humans are a cosmopolitan species. The population of humans was 6.8 billion in November 2009.

Like most higher primates, humans are social by nature. However, humans are uniquely adept at utilizing systems of communication for self-expression, the exchange of ideas, and organization. Humans create complex social structures composed of many cooperating and competing groups, from families to nations. Social interactions between humans have established an extremely wide variety of values, social norms, and rituals, which together form the basis of human society.

Humans are noted for their desire to understand and influence their environment, seeking to explain and manipulate natural phenomena through science, philosophy, mythology and religion. This natural curiosity has led to the development of advanced tools and skills, which are passed down culturally; humans are the only species known to build fires, cook their food, clothe themselves, and use numerous other technologies. Some have been able to leave the planet and visit moon.

The English adjective human is a Middle English loan from Old French humain, ultimately from Latin hūmānus, the adjective of homō "man". Use as a noun (with a plural humans) dates to the 16th century.The native English term man is now often reserved for male adults, but can still be used for "mankind" in general in Modern English. The word is from Proto-Germanic *mannaz, from a Proto-Indo-European(PIE) root *man-, cognate to Sanskrit manu-.

The generic name Homo is a learned 18th century derivation from Latin homō "man", ultimately "earthly being" (Old Latin hemō, cognate to Old English guma "man", from PIE *dʰǵʰemon-, meaning 'earth' or 'ground').

The scientific study of human evolution encompasses the development of the genus Homo, but usually involves studying other hominids and hominines as well, such as Australopithecus. "Modern humans" are defined as the Homo sapiens species, of which the only extant subspecies is known as Homo sapiens sapiens. Homo sapiens idaltu (roughly translated as "elder wise human"), the other known subspecies, is now extinct. Homo neanderthalensis, which became extinct 30,000 years ago, has sometimes been classified as a subspecies, "Homo sapiens neanderthalensis", but genetic studies now suggest a divergence of the Neanderthal species from Homo sapiens about 500,000 years ago. Similarly, the few specimens of Homo rhodesiensis have also occasionally been classified as a subspecies, but this is not widely accepted. Anatomically modern humans first appear in the fossil record in Africa about 195,000 years ago, and studies of molecular biology give evidence that the approximate time of divergence from the common ancestor of all modern human populations was 200,000 years ago. The broad study of African genetic diversity headed by Dr. Sarah Tishkoff found the San people to express the greatest genetic diversity among the 113 distinct populations sampled, making them one of 14 "ancestral population clusters". The research also located the origin of modern human migration in south-western Africa, near the coastal border of Namibia and Angola.

The closest living relatives of humans are gorillas and chimpanzees, but humans did not evolve from these apes: instead these apes share a common ancestor with modern humans. Humans are probably most closely related to two chimpanzee species: Common Chimpanzee and Bonobo. Full genome sequencing has resulted in the conclusion that "after 6.5 [million] years of separate evolution, the differences between chimpanzee and human are ten times greater than those between two unrelated people and ten times less than those between rats and mice". Suggested concurrence between human and chimpanzee DNA sequences range between 95% and 99%. It has been estimated that the human lineage diverged from that of chimpanzees about five million years ago, and from that of gorillas about eight million years ago. However, a hominid skull discovered in Chad in 2001, classified as Sahelanthropus tchadensis, is approximately seven million years old, which may indicate an earlier divergence.

Human evolution is characterized by a number of important morphological, developmental, physiological and behavioural changes, which have taken place since the split between the last common ancestor of humans and chimpanzees. The first major morphological change was the evolution of a bipedal locomotor adaptation from an arboreal or semi-arboreal one, with all its attendant adaptations, such as a valgus knee, low intermembral index (long legs relative to the arms), and reduced upper-body strength.

Later, ancestral humans developed a much larger brain – typically 1,400 cm³ in modern humans, over twice the size of that of a chimpanzee or gorilla. The pattern of human postnatal brain growth differs from that of other apes (heterochrony), and allows for extended periods of social learning and language acquisition in juvenile humans. Physical anthropologists argue that the differences between the structure of human brains and those of other apes are even more significant than their differences in size.

Other significant morphological changes included: the evolution of a power and precision grip; a reduced masticatory system; a reduction of the canine tooth; and the descent of the larynx and hyoid bone, making speech possible. An important physiological change in humans was the evolution of hidden oestrus, or concealed ovulation, which may have coincided with the evolution of important behavioural changes, such as pair bonding. Another significant behavioural change was the development of material culture, with human-made objects becoming increasingly common and diversified over time. The relationship between all these changes is the subject of ongoing debate.[26][27]

The forces of natural selection have continued to operate on human populations, with evidence that certain regions of the genome display directional selection in the past 15,000 years.

evolved from archaic Homo sapiens in Africa in the Middle Paleolithic, about 200,000 years ago. By the beginning of the Upper Paleolithic 50,000 BP (Before Present), full behavioral modernity, including language, music and other cultural universals had developed.

The broad study of African genetic diversity headed by Dr. Sarah Tishkoff found the San people to express the greatest genetic diversity among the 113 distinct populations sampled, making them one of 14 "ancestral population clusters". The research also located the origin of modern human migration in south-western Africa, near the coastal border of Namibia and Angola.

The out of Africa migration is estimated to have occurred about 70,000 years BP. Modern humans subsequently spread to all continents, replacing earlier hominids: they inhabited Eurasia and Oceania by 40,000 BP, and the Americas at least 14,500 years BP. They displaced Homo neanderthalensis and other species descended from Homo erectus (which had inhabited Eurasia as early as 2 million years ago) through more successful reproduction and competition for resources.

Evidence from archaeogenetics accumulating since the 1990s has lent strong support to the "out-of-Africa" scenario, and has marginalized the competing multiregional hypothesis, which proposed that modern humans evolved, at least in part, from independent hominid populations.

Geneticists Lynn Jorde and Henry Harpending of the University of Utah propose that the variation in human DNA is minute compared to that of other species. They also propose that during the Late Pleistocene, the human population was reduced to a small number of breeding pairs – no more than 10,000, and possibly as few as 1,000 – resulting in a very small residual gene pool. Various reasons for this hypothetical bottleneck have been postulated, one being the Toba catastrophe theory.

Until c. 10,000 years ago, most humans lived as hunter-gatherers. They generally lived in small nomadic groups known as band societies. The advent of agriculture prompted the Neolithic Revolution, when access to food surplus led to the formation of permanent human settlements, the domestication of animals and the use of metal tools. Agriculture encouraged trade and cooperation, and led to complex society. Because of the significance of this date for human society, it is the epoch of the Holocene calendar or Human Era.

About 6,000 years ago, the first proto-states developed in Mesopotamia, Egypt's Nile Valley and the Indus Valleys. Military forces were formed for protection, and government bureaucracies for administration. States cooperated and competed for resources, in some cases waging wars. Around 2,000–3,000 years ago, some states, such as Persia, India, China, Rome, and Greece, developed through conquest into the first expansive empires. Influential religions, such as Judaism, originating in the Middle East, and Hinduism, a religious tradition that originated in South Asia, also rose to prominence at this time.

The late Middle Ages saw the rise of revolutionary ideas and technologies. In China, an advanced and urbanized society promoted innovations and sciences, such as printing and seed drilling. In India, major advancements were made in mathematics, philosophy, religion and metallurgy. The Islamic Golden Age saw major scientific advancements in Muslim empires. In Europe, the rediscovery of classical learning and inventions such as the printing press led to the Renaissance in the 15th and 16th centuries. Over the next 500 years, exploration and colonialism brought much of the Americas, Asia, and Africa under European control, leading to later struggles for independence. The Scientific Revolution in the 17th century and the Industrial Revolution in the 18th–19th centuries promoted major innovations in transport, such as the railway and automobile; energy development, such as coal and electricity; and government, such as representative democracy and Communism.

With the advent of the Information Age at the end of the 20th century, modern humans live in a world that has become increasingly globalized and interconnected. As of 2008, over 1.4 billion humans are connected to each other via the Internet, and 3.3 billion by mobile phone subscriptions.

Although interconnection between humans has encouraged the growth of science, art, discussion, and technology, it has also led to culture clashes and the development and use of weapons of mass destruction. Human civilization has led to environmental destruction and pollution, producing an ongoing mass extinction of other forms of life called the holocene extinction event, that may be further accelerated by global warming in the future

Early human settlements, were dependent on proximity to water and, depending on the lifestyle, other natural resources, such as arable land for growing crops and grazing livestock, or seasonally by hunting populations of prey. However, humans have a great capacity for altering their habitats by various methods, such as through irrigation, urban planning, construction, transport, manufacturing goods, deforestation and desertification. Deliberate habitat alteration is often done with the goals of increasing material wealth, increasing thermal comfort, improving the amount of food available, improving aesthetics, or improving ease of access to resources or other human settlements. With the advent of large-scale trade and transport infrastructure, proximity to these resources has become unnecessary, and in many places, these factors are no longer a driving force behind the growth and decline of a population. Nonetheless, the manner in which a habitat is altered is often a major determinant in population change.

Technology has allowed humans to colonize all of the continents and adapt to virtually all climates. Within the last century, humans have explored Antarctica, the ocean depths, and outer space, although large-scale colonization of these environments is not yet feasible. With a population of over six billion, humans are among the most numerous of the large mammals. Most humans (61%) live in Asia. The remainder live in the Americas (14%), Africa (14%), Europe (11%), and Oceania (0.5%).

Human habitation within closed ecological systems in hostile environments, such as Antarctica and outer space, is expensive, typically limited in duration, and restricted to scientific, military, or industrial expeditions. Life in space has been very sporadic, with no more than thirteen humans in space at any given time. Between 1969 and 1972, two humans at a time spent brief intervals on the Moon. As of April 2010, no other celestial body has been visited by humans, although there has been a continuous human presence in space since the launch of the initial crew to inhabit the International Space Station on October 31, 2000. However, other celestial bodies have been visited by human-made objects.

Since 1800, the human population has increased from one billion to over six billion. In 2004, some 2.5 billion out of 6.3 billion people (39.7%) lived in urban areas, and this percentage is expected to continue to rise throughout the 21st century. In February 2008, the U.N. estimated that half the world's population will live in urban areas by the end of the year. Problems for humans living in cities include various forms of pollution and crime, especially in inner city and suburban slums.

Humans have had a dramatic effect on the environment. As humans are rarely preyed upon, they have been described as superpredators. Currently, through land development, combustion of fossil fuels and pollution, humans are thought to be the main contributor to global climate change. Human activity is believed to be a major contributor to the ongoing Holocene extinction event, which is a form of mass extinction. If this continues at its current rate it is predicted that it will wipe out half of all species over the next century.

Human body types vary substantially. Although body size is largely determined by genes, it is also significantly influenced by environmental factors such as diet and exercise. The average height of an adult human is about 1.5 to 1.8 m (5 to 6 feet) tall, although this varies significantly from place to place. The average mass of an adult human is 54–64 kg (120–140 lbs) for females and 76–83 kg (168–183 lbs) for males. Weight can also vary greatly (e.g. obesity). Unlike most other primates, humans are capable of fully bipedal locomotion, thus leaving their arms available for manipulating objects using their hands, aided especially by opposable thumbs.

Although humans appear hairless compared to other primates, with notable hair growth occurring chiefly on the top of the head, underarms and pubic area, the average human has more hair follicles on his or her body than the average chimpanzee. The main distinction is that human hairs are shorter, finer, and less heavily pigmented than the average chimpanzee's, thus making them harder to see.

The hue of human skin and hair is determined by the presence of pigments called melanins. Human skin hues can range from very dark brown to very pale pink. Human hair ranges from white to brown to red to most commonly black. This depends on the amount of melanin (an effective sun blocking pigment) in the skin and hair, with hair melanin concentrations in hair fading with increased age, leading to grey or even white hair. Most researchers believe that skin darkening was an adaptation that evolved as a protection against ultraviolet solar radiation. However, more recently it has been argued that particular skin colors are an adaptation to balance folate, which is destroyed by ultraviolet radiation, and vitamin D, which requires sunlight to form. The skin pigmentation of contemporary humans is geographically stratified, and in general correlates with the level of ultraviolet radiation. Human skin also has a capacity to darken (sun tanning) in response to exposure to ultraviolet radiation. Humans tend to be physically weaker than other similarly sized primates, with young, conditioned male humans having been shown to be unable to match the strength of female orangutans which are at least three times stronger.

Constituents of the human body

In a person weighing 60 kg

Constituent Weight Percentage of atoms

Oxygen 38.8 kg 25.5%

Carbon 10.9 kg 9.5%

Hydrogen 6.0 kg 63.0%

Nitrogen 1.9 kg 1.4%

Other 2.4 kg 0.6%

Humans have proportionately shorter palates and much smaller teeth than other primates. They are the only primates to have short, relatively flush canine teeth. Humans have characteristically crowded teeth, with gaps from lost teeth usually closing up quickly in young specimens. Humans are gradually losing their wisdom teeth, with some individuals having them congenitally absent

Human physiology is the science of the mechanical, physical, and biochemical functions of humans in good health, their organs, and the cells of which they are composed. The principal level of focus of physiology is at the level of organs and systems. Most aspects of human physiology are closely homologous to corresponding aspects of animal physiology, and animal experimentation has provided much of the foundation of physiological knowledge. Anatomy and physiology are closely related fields of study: anatomy, the study of form, and physiology, the study of function, are intrinsically tied and are studied in tandem as part of a medical curriculum.

Humans are a eukaryotic species. Each diploid cell has two sets of 23 chromosomes, each set received from one parent. There are 22 pairs of autosomes and one pair of sax chromosomes. By present estimates, humans have approximately 20,000–25,000 genes. Like other mammals, humans have an XY sex-determination system, so that females have the sex chromosomes XX and males have XY. The X chromosome carries many genes not on the Y chromosome, which means that recessive diseases associated with X-linked genes, such as haemophilia, affect men more often than women.

The human life cycle is similar to that of other placental mammals. The zygote divides inside the female's uterus to become an embryo, which over a period of thirty-eight weeks (9 months) of gestation becomes a human fetus. After this span of time, the fully grown fetus is birthed from the woman's body and breathes independently as an infant for the first time. At this point, most modern cultures recognize the baby as a person entitled to the full protection of the law, though some jurisdictions extend various levels of personhood earlier to human fetuses while they remain in the uterus.

Compared with other species, human childbirth is dangerous. Painful labors lasting twenty-four hours or more are not uncommon and sometimes leads to the death of the mother, or the child. This is because of both the relatively large fetal head circumference (for housing the brain) and the mother's relatively narrow pelvis (a trait required for successful bipedalism, by way of natural selection). The chances of a successful labor increased significantly during the 20th century in wealthier countries with the advent of new medical technologies. In contrast, pregnancy and natural childbirth remain hazardous ordeals in developing regions of the world, with maternal death rates approximately 100 times more common than in developed countries.

In developed countries, infants are typically 3–4 kg (6–9 pounds) in weight and 50–60 cm (20–24 inches) in height at birth. However, low birth weight is common in developing countries, and contributes to the high levels of infant mortality in these regions. Helpless at birth, humans continue to grow for some years, typically reaching sexual maturity at 12 to 15 years of age. Females continue to develop physically until around the age of 18, whereas male development continues until around age 21. The human life span can be split into a number of stages: infancy, childhood, adolescence, young adulthood, adulthood and old age. The lengths of these stages, however, have varied across cultures and time periods. Compared to other primates, humans experience an unusually rapid growth spurt during adolescence, where the body grows 25% in size. Chimpanzees, for example, grow only 14%, with no pronounced spurt. The presence of the growth spurt is probably necessary to keep children physically small until they are psychologically mature. Humans are one of the few species in which females undergo menopause. It has been proposed that menopause increases a woman's overall reproductive success by allowing her to invest more time and resources in her existing offspring and/or their children (the grandmother hypothesis), rather than by continuing to bear children into old age.

There are significant differences in life expectancy around the world. The developed world is generally aging, with the median age around 40 years (highest in Monaco at 45.1 years). In the developing world the median age is between 15 and 20 years. Life expectancy at birth in Hong Kong is 84.8 years for a female and 78.9 for a male, while in Swaziland, primarily because of AIDS, it is 31.3 years for both saxes. While one in five Europeans is 60 years of age or older, only one in twenty Africans is 60 years of age or older. The number of centenarians (humans of age 100 years or older) in the world was estimated by the United Nations at 210,000 in 2002.[66] At least one person, Jeanne Calment, is known to have reached the age of 122 years; higher ages have been claimed but they are not well substantiated. Worldwide, there are 81 men aged 60 or older for every 100 women of that age group, and among the oldest, there are 53 men for every 100 women.

Humans are omnivorous, capable of consuming both plant and animal products. Varying with available food sources in regions of habitation, and also varying with cultural and religious norms, human groups have adopted a range of diets, from purely vegetarian to primarily carnivorous. In some cases, dietary restrictions in humans can lead to deficiency diseases; however, stable human groups have adapted to many dietary patterns through both genetic specialization and cultural conventions to utilize nutritionally balanced food sources. The human diet is prominently reflected in human culture, and has led to the development of food science.

Until the development of agriculture approximately 10,000 years ago, Homo sapiens employed a hunter-gatherer method as their sole means of food collection. This involved combining stationary food sources (such as fruits, grains, tubers, and mushrooms, insect larvae and aquatic molluscs) with wild game, which must be hunted and killed in order to be consumed. It has been proposed that humans have used fire to prepare and cook food since the time of their divergence from Homo erectus. Around ten thousand years ago, humans developed agriculture, which substantially altered their diet. This change in diet may also have altered human biology; with the spread of dairy farming providing a new and rich source of food, leading to the evolution of the ability to digest lactose in some adults. Agriculture led to increased populations, the development of cities, and because of increased population density, the wider spread of infectious diseases. The types of food consumed, and the way in which they are prepared, has varied widely by time, location, and culture.

In general, humans can survive for two to eight weeks without food, depending on stored body fat. Survival without water is usually limited to three or four days. Lack of food remains a serious problem, with about 36 million humans starving to death every year.Childhood malnutrition is also common and contributes to the global burden of disease. However global food distribution is not even, and obesity among some human populations has increased rapidly, leading to health complications and increased mortality in some developed, and a few developing countries. Worldwide over one billion people are obese, while in the United States 35% of people are obese, leading to this being described as an "obesity epidemic". Obesity is caused by consuming more calories than are expended, so excessive weight gain is usually caused by a combination of an energy-dense high fat diet and insufficient exercise.

Humans are generally diurnal. The average sleep requirement is between seven and nine continuous hours a day for an adult and nine to ten hours for a child; elderly people usually sleep for six to seven hours. Experiencing less sleep than this is common in modern societies; this sleep deprivation can have negative effects. A sustained restriction of adult sleep to four hours per day has been shown to correlate with changes in physiology and mental state, including fatigue, aggression, and bodily discomfort.

The human brain, the focal point of the central nervous system in humans, controls the peripheral nervous system. In addition to controlling "lower", involuntary, or primarily autonomic activities such as respiration and digestion, it is also the locus of "higher" order functioning such as thought, reasoning, and abstraction. These cognitive processes constitute the mind, and, along with their behavioral consequences, are studied in the field of psychology.

Generally regarded as more capable of these higher order activities, the human brain is believed to be more "intelligent" in general than that of any other known species. Some are capable of creating structures and using simple tools—mostly through instinct and mimicry—human technology is vastly more complex, and is constantly evolving and improving through time.

Although being vastly more advanced than many species in cognitive abilities, most of these abilities are known in primitive form among other species. Modern anthropology has tended to bear out Darwin's proposition that "the difference in mind between man and the higher animals, great as it is, certainly is one of degree and not of kind".

Humans are one of only nine species to pass the mirror test—which tests whether an animal recognizes its reflection as an image of itself—along with all the great apes (gorillas, chimpanzees, orangutans, bonobos), Bottlenose dolphins, Asian elephants, European Magpies and Orcas. Most human children will pass the mirror test at 18 months old. However, the usefulness of this test as a true test of consciousness has been disputed, and this may be a matter of degree rather than a sharp divide. Monkeys have been trained to apply abstract rules in tasks.

The human brain perceives the external world through the senses, and each individual human is influenced greatly by his or her experiences, leading to subjective views of existence and the passage of time. Humans are variously said to possess consciousness, self-awareness, and a mind, which correspond roughly to the mental processes of thought. These are said to possess qualities such as self-awareness, sentience, sapience, and the ability to perceive the relationship between oneself and one's environment. The extent to which the mind constructs or experiences the outer world is a matter of debate, as are the definitions and validity of many of the terms used above. The philosopher of cognitive science Daniel Dennett, for example, argues that there is no such thing as a narrative centre called the "mind", but that instead there is simply a collection of sensory inputs and outputs: different kinds of "software" running in parallel.[83] Psychologist B.F. Skinner argued that the mind is an explanatory fiction that diverts attention from environmental causes of behavior, and that what are commonly seen as mental processes may be better conceived of as forms of covert verbal behavior.

Humans study the more physical aspects of the mind and brain, and by extension of the nervous system, in the field of neurology, the more behavioral in the field of psychology, and a sometimes loosely defined area between in the field of psychiatry, which treats mental illness and behavioral disorders. Psychology does not necessarily refer to the brain or nervous system, and can be framed purely in terms of phenomenological or information processing theories of the mind. Increasingly, however, an understanding of brain functions is being included in psychological theory and practice, particularly in areas such as artificial intelligence, neuropsychology, and cognitive neuroscience.

The nature of thought is central to psychology and related fields. Cognitive psychology studies cognition, the mental processes' underlying behavior. It uses information processing as a framework for understanding the mind. Perception, learning, problem solving, memory, attention, language and emotion are all well researched areas as well. Cognitive psychology is associated with a school of thought known as cognitivism, whose adherents argue for an information processing model of mental function, informed by positivism and experimental psychology. Techniques and models from cognitive psychology are widely applied and form the mainstay of psychological theories in many areas of both research and applied psychology. Largely focusing on the development of the human mind through the life span, developmental psychology seeks to understand how people come to perceive, understand, and act within the world and how these processes change as they age. This may focus on intellectual, cognitive, neural, social, or moral development.

Some philosophers divide consciousness into phenomenal consciousness, which is experience itself, and access consciousness, which is the processing of the things in experience. Phenomenal consciousness is the state of being conscious, such as when they say "I am conscious." Access consciousness is being conscious of something in relation to abstract concepts, such as when one says "I am conscious of these words." Various forms of access consciousness include awareness, self-awareness, conscience, stream of consciousness, Husserl's phenomenology, and intentionality. The concept of phenomenal consciousness, in modern history, according to some, is closely related to the concept of qualia. Social psychology links sociology with psychology in their shared study of the nature and causes of human social interaction, with an emphasis on how people think towards each other and how they relate to each other. The behavior and mental processes, both human and non-human, can be described through animal cognition, ethology, evolutionary psychology, and comparative psychology as well. Human ecology is an academic discipline that investigates how humans and human societies interact with both their natural environment and the human social environment

Motivation is the driving force of desire behind all deliberate actions of humans. Motivation is based on emotion—specifically, on the search for satisfaction (positive emotional experiences), and the avoidance of conflict. Positive and negative is defined by the individual brain state, which may be influenced by social norms: a person may be driven to self-injury or violence because their brain is conditioned to create a positive response to these actions. Motivation is important because it is involved in the performance of all learned responses. Within psychology, conflict avoidance and the libido are seen to be primary motivators. Within economics, motivation is often seen to be based on incentives; these may be financial, moral, or coercive. Religions generally posit divine or demonic influences.

Happiness, or the state of being happy, is a human emotional condition. The definition of happiness is a common philosophical topic. Some people might define it as the best condition that a human can have—a condition of mental and physical health. Others define it as freedom from want and distress; consciousness of the good order of things; assurance of one's place in the universe or society.

Emotion has a significant influence on, or can even be said to control, human behavior, though historically many cultures and philosophers have for various reasons discouraged allowing this influence to go unchecked. Emotional experiences perceived as pleasant, such as love, admiration, or joy, contrast with those perceived as unpleasant, like hate, envy, or sorrow. There is often a distinction made between refined emotions that are socially learned and survival oriented emotions, which are thought to be innate. Human exploration of emotions as separate from other neurological phenomena is worthy of note, particularly in cultures where emotion is considered separate from physiological state. In some cultural medical theories emotion is considered so synonymous with certain forms of physical health that no difference is thought to exist. The Stoics believed excessive emotion was harmful, while some Sufi teachers felt certain extreme emotions could yield a conceptual perfection, what is often translated as ecstasy.

In modern scientific thought, certain refined emotions are considered a complex neural trait innate in a variety of domesticated and non-domesticated mammals. These were commonly developed in reaction to superior survival mechanisms and intelligent interaction with each other and the environment; as such, refined emotion is not in all cases as discrete and separate from natural neural function as was once assumed. However, when humans function in civilized tandem, it has been noted that uninhibited acting on extreme emotion can lead to social disorder and crime.

Human saxuality besides ensuring biological reproduction, has important social functions: it creates physical intimacy, bonds, and hierarchies among individuals; may be directed to spiritual transcendence (according to some traditions); and in a hedonistic sense to the enjoyment of activity involving sexual gratification. Sexual desire, or libido, is experienced as a bodily urge, often accompanied by strong emotions such as love, ecstasy and jealousy. The extreme importance of sexuality in the human species can be seen in a number of physical features, among them hidden ovulation, the evolution of external scrotum and penis suggesting sperm competition, the absence of an os penis, permanent secondary sexual characteristics, the forming of pair bonds based on sexual attraction as a common social structure and sexual ability in females outside of ovulation. These adaptations indicate that the importance of sexuality in humans is on a par with that found in the Bonobo, and that the complex human sexual behaviour has a long evolutionary history.

Human choices in acting on sexuality are commonly influenced by cultural norms, which vary widely. Restrictions are often determined by religious beliefs or social customs. The pioneering researcher Sigmund Freud believed that humans are born polymorphously perverse, which means that any number of objects could be a source of pleasure. According to Freud, humans then pass through five stages of psychosexual development (and can fixate on any stage because of various traumas during the process). For Alfred Kinsey, another influential sex researcher, people can fall anywhere along a continuous scale of sexual orientation (with only small minorities fully heterosexual or homosexual). Recent studies of neurology and genetics suggest people may be born with a predisposition to one sexual orientation or another.

But cultural attainment is defined here as a set of distinctive material, intellectual, emotional, and spiritual features of a social group, including art, literature, sport, lifestyles, value systems, traditions, rituals, and beliefs. The link between human biology and human behavior and culture is often very close, making it difficult to clearly divide topics into one area or the other; as such, the placement of some subjects may be based primarily on convention. Culture consists of values, social norms, and artifacts. A culture's values define what it holds to be important or ethical. Closely linked are norms, expectations of how people ought to behave, bound by tradition. Artifacts, or material culture, are objects derived from the culture's values, norms, and understanding of the world.

The capacity humans have to transfer concepts, ideas and notions through speech and writing is unrivaled in known species. Unlike the call systems of other primates that are closed, human language is far more open, and gains variety in different situations. The human language has the quality of displacement, using words to represent things and happenings that are not presently or locally occurring, but elsewhere or at a different time. In this way data networks are important to the continuing development of language. The faculty of speech is a defining feature of humanity, possibly predating phylogenetic separation of the modern population. Language is central to the communication between humans, as well as being central to the sense of identity that unites nations, cultures and ethnic groups. The invention of writing systems at least 5,000 years ago allowed the preservation of language on material objects, and was a major step in cultural evolution. The science of linguistics describes the structure of language and the relationship between languages. There are approximately 6,000 different languages currently in use, including sign languages, and many thousands more that are considered extinct.

Relious feeling is generally defined as a belief system concerning the supernatural, sacred or divine, and moral codes, practices, values, institutions and rituals associated with such belief. The evolution and the history of the first religions have recently become areas of active scientific investigation. However, in the course of its development, religion has taken on many forms that vary by culture and individual perspective. Some of the chief questions and issues religions are concerned with include life after death (commonly involving belief in an afterlife), the origin of life, the nature of the universe (religious cosmology) and its ultimate fate (eschatology), and what is moral or immoral. A common source in religions for answers to these questions are beliefs in transcendent divine beings such as deities or a singular God, although not all religions are theistic—many are nontheistic or ambiguous on the topic, particularly among the Eastern religions. Spirituality, belief or involvement in matters of the soul or spirit, is one of the many different approaches humans take in trying to answer fundamental questions about humankind's place in the universe, the meaning of life, and the ideal way to live one's life. Though these topics have also been addressed by philosophy, and to some extent by science, spirituality is unique in that it focuses on mystical or supernatural concepts such as karma and God.

Although the exact level of religiosity can be hard to measure,a majority of humans professes some variety of religious or spiritual belief, although some are irreligious: that is lacking or rejecting belief in the supernatural or spiritual. Other humans have no religious beliefs and are atheists, scientific skeptics, agnostics or simply non-religious. Humanism is a philosophy which seeks to include all of humanity and all issues common to humans; it is usually non-religious. Additionally, although most religions and spiritual beliefs are clearly distinct from science on both a philosophical and methodological level, the two are not generally considered mutually exclusive; a majority of humans holds a mix of both scientific and religious views. The distinction between philosophy and religion, on the other hand, is at times less clear, and the two are linked in such fields as the philosophy of religion and theology.

Philosophical thought and consideration is a discipline or field of study involving the investigation, analysis, and development of ideas at a general, abstract, or fundamental level. It is the discipline searching for a general understanding of reality, reasoning and values. Major fields of philosophy include logic, metaphysics, epistemology, philosophy of mind, and axiology (which includes ethics and aesthetics). Philosophy covers a very wide range of approaches, and is used to refer to a worldview, to a perspective on an issue, or to the positions argued for by a particular philosopher or school of philosophy.

Artistic works have existed for almost as long as humankind, from early pre-historic art to contemporary art. Art is one of the most unusual aspects of human behaviour and a key distinguishing feature of humans from other species.

As a form of cultural expression by humans, art may be defined by the pursuit of diversity and the usage of narratives of liberation and exploration (i.e. art history, art criticism, and art theory) to mediate its boundaries. This distinction may be applied to objects or performances, current or historical, and its prestige extends to those who made, found, exhibit, or own them. In the modern use of the word, art is commonly understood to be the process or result of making material works that, from concept to creation, adhere to the "creative impulse" of human beings. Art is distinguished from other works by being in large part unprompted by necessity, by biological drive, or by any undisciplined pursuit of recreation.

Music is a natural intuitive phenomenon based on the three distinct and interrelated organization structures of rhythm, harmony, and melody. Listening to music is perhaps the most common and universal form of entertainment for humans, while learning and understanding it are popular disciplines. There are a wide variety of music genres and ethnic musics. Literature, the body of written—and possibly oral—works, especially creative ones, includes prose, poetry and drama, both fiction and non-fiction. Literature includes such genres as epic, legend, myth, ballad, and folklore.

Stone tools were used by proto-humans at least 2.5 million years ago. The controlled use of fire began around 1.5 million years ago. Since then, humans have made major advances, developing complex technology to create tools to aid their lives and allowing for other advancements in culture. Major leaps in technology include the discovery of agriculture - what is known as the Neolithic Revolution; and the invention of automated machines in the Industrial Revolution.

Archaeology attempts to tell the story of past or lost cultures in part by close examination of the artifacts they produced. Early humans left stone tools, pottery and jewelry that are particular to various regions and times

The sexual division of humans into male and female has been marked culturally by a corresponding division of roles, norms, practices, dress, behavior, rights, duties, privileges, status, and power. Cultural differences by gender have often been believed to have arisen naturally out of a division of reproductive labor; the biological fact that women give birth led to their further cultural responsibility for nurturing and caring for children and households. Gender roles have varied historically, and challenges to predominant gender norms have recurred in many societies. As a whole, partriarchal societies (i.e., in which men hold the greater degree of economic and political power) have been predominant, and matriarchal or egalitarian societies less common.

Humans often categorize themselves in terms of race or ethnicity, sometimes on the basis of differences in appearance. Human racial categories have been based on both ancestry and visible traits, especially facial features, skin color and hair texture. Most current genetic and archaeological evidence supports a recent single origin of modern humans in East Africa.[96] Current genetic studies have demonstrated that humans on the African continent are most genetically diverse. However, compared to the other great apes, human gene sequences are remarkably homogeneous. The predominance of genetic variation occurs within racial groups, with only 5 to 15% of total variation occurring between groups.[102] Thus the scientific concept of variation in the human genome is largely incongruent with the cultural concept of ethnicity or race. Ethnic groups are defined by linguistic, cultural, ancestral, national or regional ties. Self-identification with an ethnic group is usually based on kinship and descent. Race and ethnicity are among major factors in social identity giving rise to various forms of identity politics, e.g.: racism.

There is no scientific consensus of a list of the human races, and few anthropologists endorse the notion of human "race".For example, a color terminology for race includes the following in a classification of human races: Black (e.g. Sub-Saharan Africa), Red (e.g. Native Americans), Yellow (e.g. East Asians) and White (e.g. Europeans).

Referring to natural species, in general, the term "race" is obsolete, particularly if a species is uniformly distributed on a territory. In its modern scientific connotation, the term is not applicable to a species as genetically homogeneous as the human one, as stated in the declaration on race (UNESCO 1950).

Genetic studies have substantiated the absence of biological borders, thus the term "race" has de facto disappeared from the scientific terminology, both in biological anthropology and in human genetics.

What in the past had been defined as "races"—e.g., whites, blacks, or Asians—are now defined as "ethnic groups" or "populations", in correlation with the field (sociology, anthropology, genetics) in which they are considered.

Society is the system of organizations and institutions arising from interaction between humans. A state is an organized political community occupying a definite territory, having an organized government, and possessing internal and external sovereignty. Recognition of the state's claim to independence by other states, enabling it to enter into international agreements, is often important to the establishment of its statehood. The "state" can also be defined in terms of domestic conditions, specifically, as conceptualized by Max Weber, "a state is a human community that (successfully) claims the monopoly of the 'legitimate' use of physical force within a given territory."

Government can be defined as the political means of creating and enforcing laws; typically via a bureaucratic hierarchy. Politics is the process by which decisions are made within groups. Although the term is generally applied to behavior within governments, politics is also observed in all human group interactions, including corporate, academic, and religious institutions. Many different political systems exist, as do many different ways of understanding them, and many definitions overlap. Examples of governments include monarchy, Communist state, military dictatorship, and theocracy. All of these issues have a direct relationship with economics.

War is a state of widespread conflict between states or other large groups of humans, which is characterized by the use of lethal violence between combatants and/or upon civilians. It is estimated that during the 20th century between 167 and 188 million humans died as a result of war. A common perception of war is a series of military campaigns between at least two opposing sides involving a dispute over sovereignty, territory, resources, religion, or other issues. A war between internal elements of a state is a civil war.

There have been a wide variety of rapidly advancing tactics throughout the history of war, ranging from conventional war to asymmetric warfare to total war and unconventional warfare. Techniques include hand to hand combat, the use of ranged weapons, and, more recently, air support. Military intelligence has often played a key role in determining victory and defeat. Propaganda, which often includes information, slanted opinion and disinformation, plays a key role in maintaining unity within a warring group, and/or sowing discord among opponents. In modern warfare, soldiers and armoured fighting vehicles are used to control the land, warships the sea, and aircraft the sky. These fields have also overlapped in the forms of marines, paratroopers, naval aircraft carriers, and surface-to-air missiles, among others. Satellites in low Earth orbit have made outer space a factor in warfare as well, although no actual warfare is currently known to be carried out in space.

Trade is the voluntary exchange of goods and services, and is a form of economics. A mechanism that allows trade is called a market. The original form of trade was barter, the direct exchange of goods and services. Modern traders instead generally negotiate through a medium of exchange, such as money. As a result, buying can be separated from selling, or earning. The invention of money (and later credit, paper money and non-physical money) greatly simplified and promoted trade. Because of specialization and division of labor, most people concentrate on a small aspect of manufacturing or service, trading their labour for products. Trade exists between regions because different regions have an absolute or comparative advantage in the production of some tradable commodity, or because different regions' size allows for the benefits of mass production.

Economics is a social science which studies the production, distribution, trade, and consumption of goods and services. Economics focuses on measurable variables, and is broadly divided into two main branches: microeconomics, which deals with individual agents, such as households and businesses, and macroeconomics, which considers the economy as a whole, in which case it considers aggregate supply and demand for money, capital and commodities. Aspects receiving particular attention in economics are resource allocation, production, distribution, trade, and competition. Economic logic is increasingly applied to any problem that involves choice under scarcity or determining economic value. Mainstream economics focuses on how prices reflect supply and demand, and uses equations to predict consequences of decisions.

Homo habilis (pronounced homo/h.m (RP) hæbls/) ("handy man") is a species of the genus Homo, which lived from approximately 2.3 to 1.4 million years ago at the beginning of the Pleistocene period. The discovery and description of this species is credited to both Mary and Louis Leakey, who found fossils in Tanzania, East Africa, between 1962 and 1964. [2] Homo habilis (or possibly H. rudolfensis) is the earliest known species of the genus Homo. In its appearance and morphology, H. habilis is thus the least similar to modern humans of all species in the genus (except possibly H. rudolfensis). H. habilis was short and had disproportionately long arms compared to modern humans; however, it had a less protruding face than the australopithecines from which it is thought to have descended. H. habilis had a cranial capacity slightly less than half of the size of modern humans. Despite the ape-like morphology of the bodies, H. habilis remains are often accompanied by primitive stone tools (e.g. Olduvai Gorge, Tanzania and Lake Turkana, Kenya).

Homo habilis has often been thought to be the ancestor of more gracile and sophisticated Homo ergaster, which in turn gave rise to the more human-appearing species, Homo erectus. Debates continue over whether H. habilis is a direct human ancestor, and whether all of the known fossils are properly attributed to the species. However, in 2007, new findings suggest that the two species coexisted and may be separate lineages from a common ancestor instead of H. erectus being descended from H. habili

One set of fossil remains (OH 62), discovered by Donald Johanson and Tim White in Olduvai Gorge in 1986, included the important upper and lower limbs. An older (1963) finding from the Olduvai site found by N. Mbuika had included a lower jaw fragment, teeth and upper mandible possibly from a female dating 1.7 million years old. The remains from 3 skeletons stacked on top of each other demonstrated australopithecine-like body with a more human-like face and smaller teeth. Compared to australopithecines, H. habilis's brain capacity of 363 and 600 cm³ was on average 50% larger than australopithecines, but considerably smaller than the 1350 to 1450 cm³ range of modern Homo sapiens. These hominins were smaller than modern humans, on average standing no more than 1.3 m (4 ft 3 in) tall.

The small size and rather primitive attributes have led some experts (Richard Leakey among them) to propose excluding H. habilis from the genus Homo, and renaming as "Australopithecus habilis".

knm813 is a relatively complete cranium which dates 1.9 million years old, discovered at Koobi Fora, Kenya by Kamoya Kimeu in 1973. The brain capacity is 510 cm³, not as impressive as other early specimen and forms of Homo habilis discovered.

OH 7 dates 1.75 million years old and was discovered by Jonathan Leakey on November 4, 1960 at Olduvai Gorge, Tanzania. It is a lower jaw complete with teeth and due to the size of the small teeth; researchers estimate this individual had a brain volume of 363 cm³. Also found were more than 20 fragments of the left hand. Tobias and Napier assisted in classifying OH-7 as the type fossil.

OH 24 is a roughly deformed cranium dating 1.8 million years old discovered in October 1968 at Olduvai Gorge, Tanzania by Peter Nzube. The brain volume is just under 600 cm³; also a reduction in a protruding face is present compared to members of more primitive Australopithecines. Twiggy was found in a distorted matrix with a coating of limestone rock.

KNM ER 1805 is a specimen of an adult H. habilis made of 3 pieces of cranium dating 1.74 million years old from Koobi Fora, Kenya. Previous assumptions were that this specimen belongs to H. erectus based on the degree of prognathism and overall cranial shape.

Homo habilis is thought to have mastered the Olduwan era (Early Paleolithic) tool case which utilized stone flakes. These stone flakes were more advanced than any tools previously used, and gave H. habilis the edge it needed to prosper in hostile environments previously too formidable for primates. Whether H. habilis was the first hominin to master stone tool technology remains controversial, as Australopithecus garhi, dated to 2.6 million years ago, has been found along with stone tool implements at least 100,000 - 200,000 years older than H. habilis.

Most experts assume the intelligence and social organization of H. habilis were more sophisticated than typical australopithecines or chimpanzees. Yet despite tool usage, H. habilis was not the master hunter that its sister species (or descendants) proved to be, as there is ample fossil evidence that H. habilis was a staple in the diet of large predatory animals such as Dinofelis, a large scimitar-toothed predatory cat the size of a jaguar. H. habilis used tools primarily for scavenging, such as cleaving meat off carrion, rather than defense or hunting. Homo habilis is thought to be the ancestor of the lankier and more sophisticated Homo ergaster, which in turn gave rise to the more human-appearing species Homo erectus. Debates continue over whether H. habilis is a direct human ancestor, and whether all of the known fossils are properly attributed to the species.

Homo habilis co-existed with other Homo-like bipedal primates, such as Paranthropus boisei, some of which prospered for many millennia. However, H. habilis, possibly because of its early tool innovation and a less specialized diet, became the precursor of an entire line of new species, whereas Paranthropus boisei and its robust relatives disappeared from the fossil record. Homo habilis may also have coexisted with Homo erectus in Africa for a period of 500,000 years

Homo erectus (from the Latin ērĭgĕre, "to put up, set upright") is an extinct species of hominid that originated in Africa—and spread as far as China and Java—from the end of the Pliocene epoch to the later Pleistocene, about 1.8 to 1.3 million years ago. There is still disagreement on the subject of the classification, ancestry, and progeny of H. erectus, with two major alternative hypotheses: erectus may be another name for Homo ergaster, and therefore the direct ancestor of later hominids such as Homo heidelbergensis, Homo neanderthalensis, and Homo sapiens; or it may be an Asian species distinct from African ergaster

H. erectus originally migrated from Africa during the Early Pleistocene, possibly as a result of the operation of the Saharan pump, around 2.0 million years ago, and dispersed throughout much of the Old World. Fossilized remains 1.8 and 1.0 million years old have been found in Africa (e.g., Lake Turkana and Olduvai Gorge), Europe (Georgia, Spain), Indonesia (e.g., Sangiran and Trinil), Vietnam, and China (e.g., Shaanxi

Dutch anatomist Eugene Dubois, who was fascinated especially by Darwin's theory of evolution as applied to man, set out to Asia (the place accepted then, despite Darwin, as the cradle of human evolution), to find a human ancestor in 1886. In 1891, his team discovered a human fossil on the island of Java, Indonesia; he described the species as Pithecanthropus erectus (from the Greek πίθηκος, "ape", andνθρωπος, "man"), based on a calotte (skullcap) and a femur like that of H. sapiens found from the bank of the Solo River at Trinil, in East Java. (This species is now regarded as Homo erectus.)

The find became known as Java Man. Thanks to Canadian anatomist Davidson Black's (1921) initial description of a lower molar, which was dubbed Sinanthropus pekinensis, however, most of the early and spectacular discoveries of this taxon took place at Zhoukoudian in China. German anatomist Franz Weidenreich provided much of the detailed description of this material in several monographs published in the journal Palaeontologica Sinica (Series D).

Nearly all of the original specimens were lost during World War II, however; yet authentic Weidenreichian casts do exist at the American Museum of Natural History in New York and at the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing, and are considered to be reliable evidence.

Throughout much of the 20th century, anthropologists debated the role of H. erectus in human evolution. Early in the century, however, due to discoveries on Java and at Zhoukoudian, it was believed that modern humans first evolved in Asia. A few naturalists (Charles Darwin most prominent among them) predicted that humans' earliest ancestors were African: he pointed out that chimpanzees and gorillas, obviously human relatives, live only in Africa.

From 1950s to 1970s, however, numerous fossil finds from East Africa yielded evidence that the oldest hominins originated there. It is now believed that H. erectus is a descendant of earlier genera such as Ardipithecus and Australopithecus, or early Homo-species such as H. habilis or H. ergaster. H. habilis and H. erectus coexisted for several thousand years, and may represent separate lineages of a common ancestor.

The skull of Tchadanthropus uxoris, discovered in 1961 by Yves Coppens in Chad, is the earlier fossil human discovered in Africa. Though some first considered it to be a specimen of H. habilis, it is no longer considered to be a valid taxon, and scholars rather consider it to represent H. erectus

Many paleoanthropologists still debate the definition of H. erectus and H. ergaster as separate species. Some call H. ergaster the direct African ancestor of H. erectus, proposing that it emigrated out of Africa and migrated into Asia, branching into a distinct species. Most dispense with the species-name ergaster, making no distinction between such fossils as the Turkana Boy and Peking Man.[citation needed] Though "Homo ergaster" has gained some acceptance as a valid taxon, these two are still usually defined as distinct African and Asian populations of the larger species H. erectus.

While some have argued (and insisted) that Ernst Mayr's biological species definition cannot be used here to test the above hypotheses, one can, however, examine the amount of morphological cranial variation within known H. erectus / H. ergaster specimens, and compare it to what one sees in disparate extant groups of primates with similar geographical distribution or close evolutionary relationship. Thus, if the amount of variation between H. erectus and H. ergaster is greater than what one sees within a species of, say, macaques, then H. erectus and H. ergaster may be considered two different species.

The extant model of comparison is very important, and selecting appropriate species can be difficult. (For example, the morphological variation among the global population of H. sapiens is incredibly small, as attested by the Mitochondrial Eve hypothesis, and our own special diversity may not be a trustworthy comparison.) Another closely related, and possibly ancestral, species is Homo georgicus: fossils examples of this species were found in Dmanisi in the Republic of Georgia, and are considered to display traits intermediate between H. erectus and H. habilis.

H. erectus had a cranial capacity greater than that of Homo habilis (although the Dmanisi specimens have distinctively small crania): the earliest remains show a cranial capacity of 850 cm³, while the latest Javan specimens measure up to 1100 cm³ , overlapping that of H. sapiens.; the frontal bone is less sloped and the dental arcade smaller than the australopithecines'; the face is more orthognatic (less protrusive) than either the australopithecines' or H. habilis's, with large brow-ridges and less prominent zygomata (cheekbones). These early hominins stood about 1.79 m (5 ft 10+1⁄2 in), and were robuster than modern humans.

The sexual dimorphism between males and females was slightly greater than seen in H. sapiens, with males being about 25% larger than females. The discovery of the skeleton KNM-WT 15000, "Turkana boy" (Homo ergaster), made near Lake Turkana, Kenya by Richard Leakey and Kamoya Kimeu in 1984, is one of the most complete hominid-skeletons discovered, and has contributed greatly to the interpretation of human physiological evolution.

For the remainder of this article, the name Homo erectus will be used to describe a distinct species for the convenience of continuity.

Homo ergaster used more diverse and sophisticated stone tools than its predecessors: H. erectus, however, used comparatively primitive tools. This is possibly because H. ergaster first used tools of Oldowan technology and later progressed to the Acheulean: while the use of Acheulean tools began ca. 1.6 million years ago, the line of H. erectus diverged some 200,000 years before the general innovation of Acheulean technology. Thus the Asian migratory descendants of H. ergaster made no use of any Acheulean technology. In addition, it has been suggested that H. erectus may have been the first hominid to use rafts to travel over oceans

Homo erectus was probably the first human to live in an hunter-gatherer society, and anthropologists such as Richard Leakey believe that it was socially more like to modern humans than the more Australopithecus-like species before it. Likewise, increased cranial capacity generally coincides with the more sophisticated tools occasionally found with fossils.

The discovery of Turkana boy (H. ergaster) in 1984 gave evidence that, despite its Homo-sapiens-like anatomy, it may not have been capable of producing sounds comparable to modern human speech. Ergaster at least may have communicated with a pre-language lacking the fully developed structure of modern human language, but more developed than the basic communication used by chimpanzees. Such inference has been challenged by the discovery of H. ergaster/erectus vertebrae some 150,000 years older than the Turkana Boy in Dmanisi, Georgia, that reflect vocal capabilities within the range of H. sapiens.Both brain-size and the presence of the Broca's area also support the use of articulate language.

H. erectus was probably the first hominid to live in small, familiar band-societies similar to modern hunter-gatherer band-societies. H. erectus/ergaster is thought to be the first hominid to hunt in coordinated groups, use complex tools, and care after infirm or weak companions.

Sites in Europe and Asia seem to indicate controlled use of fire by H. erectus, some dating back 1.5 million years ago. A presentation at the Paleoanthropology Society annual meeting in Montreal, Canada in March 2004 stated that there is evidence for controlled fires in excavations in northern Israel from about 690,000 to 790,000 years ago. A site called Terra Amata, located on the French Riviera, which lies on an ancient beach, seems to have been occupied by H. erectus; it contains the earliest evidence of controlled fire, dated at around 300,000 years BC. Excavations dating from approximately 790,000 years ago in Israel suggest that H. erectus not only controlled fire but could light fires. Despite these examples, some scholars continue to assert that the controlled use of fire was not typical of H. erectus, but only of later species of Homo, such as H. heidelbergensis, H. neanderthalensis, and H. sapiens).

There has been some debate as to whether H. erectus, and possibly the later Neanderthals may have interbred with anatomically modern humans in Europe and Asia. Genetic evidence largely does not support this hypothesis (see Neanderthal admixture

Yuanmou Man (simplified Chinese: traditional Chinese: pinyin: Yuánmóu Rén), Homo erectus yuanmouensis, refers to a member of the homo genus whose remnants, two incisors, were discovered near Danawu Village in Yuanmou County (simplified Chinese:traditional Chinese: pinyin: Yuánmóu Xiàn) in southwestern province of Yunnan, China. Later, stone artifacts, pieces of animal bone showing signs of human work and ash from campfires were also dug up from the site. The fossils are on display at the National Museum of China, Beijing.

The remnants of Yuanmou Man were discovered on May 1, 1965, by the geologist Fang Qian, who was working for the Geological Mechanics Research Institute. Based on the palaeomagnetic dating of the rock they were found in, it was initially estimated that the fossils were about 1.7 Ma BP and thus represented the earliest fossils of human ancestors found in China and East Asia. It may be predated by the Wushan Man

The dating has been indirectly questioned by Geoffrey Pope who argued that evidence does not support the appearance of hominidae in Asia prior to 1 million years ago. (this skepticism has since lifted, with additional finds in the last 25 years). There are still, however, conflicting opinions regarding the age of the Yuanmou Fm. and Yuanmou Man. You et al. (1978) suggested that Member 4 in the upper part of the formation is middle Pleistocene and should be designated the Shangnabang Fm., while the sediments exposed at Shagou containing Enhydriodon cf. falconeri should be designated the Shagou Fm. with an age of Pliocene. Liu et al. (1983) believed the age of Yuanmou Man was Middle Pleistocene, did not exceed 0.73 Ma BP, and was probably contemporaneous with Peking Man. Subsequently, Qian (1985) conducted further studies of the age of Yuanmou Man, but still obtained an age of 1.7 Ma BP, or Early Pleistocene. These investigations initiated beneficial discussion, although further conflicting opinions persist regarding depositional environment, paleoclimatology, glaciation, and other aspects. According to Qian et al. (1991), palaeomagnetic dates from near where the teeth were recovered average 1.7 Ma BP. Older research by Liu and Ding (1984) noted that the faunal sequence at the site was inverted, with more extinct species in the upper levels than deeper in the deposit, and based on this evidence they suggest to put the age of the Yuanmou man into the Middle Pleistocene, that is about 0.5 - 0.6 Ma BP.

Lantian Man (simplified Chinese:traditional Chinese: pinyin: Lántián rén), formerly Sinanthropus lantianensis (currently Homo erectus lantianensis) is a subspecies of Homo erectus. Its discovery in 1963 was first described by J. K. Woo the following year.

Remnants of Lantian Man (called Lantian Ren;in Chinese) were found in Lantian County (pinyin: Lántián Xiàn), in China's northwestern Shaanxi province, approximately 50 km southeast of the city of Xi'an. Shortly after the discovery of the mandible (jaw bone) of the first Lantian Man at Chenjiawo, also in Lantian County, a cranium (skull) with nasal bones, right maxilla, and three teeth of another specimen of Lantian Man were found at Gongwangling , another site in Lantian County.

The cranial capacity is estimated to be 780 cubic centimetres (48 cu in), somewhat similar to that of its contemporary, Java Man.

Lantian Man is older than the better-known Peking Man, but possibly younger than Yuanmou Man, who according to some estimates may have lived about 1.7 million years ago in modern-day China.

These fossils are believed to come from two females who lived about 530,000 to 1 million years ago, the second being the older one by about 400,000 years. Gongwangling Man represents the oldest fossil of an erect human ever found in northern Asia. Scientists classify Lantian Man as a subspecies of Homo erectus. The fossils are displayed at the Shaanxi History Museum, Xi'an, China.

In the same strata as and close to the Lantian Man fossils, animal fossils and stone artifacts were found, such as treated pebbles and flakes. The presence of these stone artifacts and as well as ashes suggests that Lantian Man used tools and could control fire.

Wushan Man (Chinese:) is a controversial taxon. Originally considered a subspecies of Homo erectus, it is now thought by one of the scientists, Russell Ciochon, that first described it to be based upon fossilized fragments of an extinct non-hominin ape. The remains that have become known as "Wushan Man" were found in 1985 in Longgupo, Zhenlongping Village, Miaoyu Town of Wushan County, Chongqing in the Three Gorges area of China 20 kilometres (12 mi) south of the Yangtze River. They have been dated to around two million years ago.

The cave at Longgupo is locally known as Dragon Bone Slope due the way the collapse of the cave's roof and walls shaped the above land.fig. 1 It was discovered as a site contain fossils in 1984 and then initially excavated by a team of Chinese scientists, led by Huang Wanpo of the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing and the Chongqing National Museum (Sichuan Province) from 1985 to until 1988. The deposits on the cave floor are over 22 m deep, with the 10 m containing fossils overlain by 12 m that do not.fig. 2 In 1986, three fore-teeth and a left mandible with two molars were unearthed together with the animal fossils including teeth from an extinct type of large ape Gigantopithecus and an extinct pygmy giant panda Ailuropoda microta. Excavations carried between 1997 and 1999 and then between 2003 and 2006 have found additional stone tools and animal fossils including remains of 120 species of vertebrates, of which 116 are mammals. This suggests the fossils existed originally in a subtropical forest environment.

The presence of Sinomastodon, Nestoritherium, Equus yunnanensis, Ailuropoda microta remains in the level containing the jaw suggested that its remains belonged to the earliest part of the Pleistocene or late Pliocene. Dating of the layers containing the fossil remains was initially done using archaeomagnetic dating of traces of the Earth's ancient magnetic field. These confirmed a Pleistocene age linking the fossil jaw to around 1.78 million to 1.96 million years ago and so the same time as the human fossils that appeared in Africa's Olduvai Gorge. Later in 1992, a joint Chinese-American-Canadian research team using electron spin resonance dating and a deer tooth from one of the cave's upper levels three meters above that containing the jaw dated this level to a minimum age of 750,000 years and a most likely age of 1 million making the layers below at least and probably much older in date than this. More recent dating techniques suggest the layer containing the fossils are 2 million to 2.04 million years old.

Early reports of the excavation were in Chinese journals and did not gather attention from outside China. In 1992, Russell Ciochon was invited to Longgupo to examine and provide a reliable age for the jaw. This led to the published in 1995 by Ciochon and Chinese paleoanthropologist of the findings in the journal Nature.

According to the Nature paper

The new evidence suggests that hominids entered Asia before 2 Myr, coincident with the earliest diversification of genus Homo in Africa. Clearly, the first hominid to arrive in Asia was a species other than true H. erectus, and one that possessed a stone-based technology. A pre-erectus hominid in China as early as 1.9 Myr provides the most likely antecedents for the in situ evolution of Homo erectus in Asia.

This makes its status as a Homo fossil critically important to the study of humans origins as it suggests that H. erectus was not the first human species to leave Africa and supports the argument made by some that H. erectus evolved in Asia and not Africa.

The discovery of Homo floresiensis also makes evidence of a pre-erectus hominin in Asia important. Recent research finds its wrist and foot bones to be anatomically like those of H. habilis or Australopithecus. Evidence for pre-erectus Homo in Asia would be consistent with such a possible origin.

Reflecting its status, a middle school textbook "The Chinese History" (published by People's Education Press) has been planned that includes the discovery of "Wushan Man".

In a Science report in 1995 upon the finding several doubts were raised including one by Milford Wolpoff

Milford Wolpoff of the University of Michigan, who saw the specimens on a trip to China several years ago, isn't even convinced that the partial jaw is a hominid. "I believe it is a piece of an orangutan or other Pongo," he says. He bases that conclusion on a wear facet on the preserved premolar, which to him suggests that the missing neighboring tooth is shaped more like an orang's than a human's.

Jeffrey Schwartz and Ian Tattersall published a claim in Nature that the teeth found in Longgupo were those of an orangutan. But the teeth are outside the range of variation of those found in orangutans ruling out this possibility.

More recently, the jaw fragment has been argued to be indistinguishable from Late Miocene-Pliocene Chinese apes of the genus Lufengpithecus. The incisor has also been argued to be consistent with that of an East Asian person that accidentally entered the deposit: "brought in by flowing water or other forces into the fissure of the comparatively old Longgupo Cave deposits".

In 18 June 2009 issue of Nature, Russell Ciochon who first reported the jaw fragment from Longgupo as human announced that he now had changed his mind and considers that it belongs to an unknown extinct ape.

I am now convinced that the Longgupo fossil and others like it do not represent a pre-erectus human, but rather one or more mystery apes indigenous to southeast Asia’s Pleistocene primal forest. In contrast, H. erectus arrived in Asia about 1.6 million years ago, but steered clear of the forest in pursuit of grassland game. There was no pre-erectus species in southeast Asia after all.

Russell Ciochon changed his mind since he no longer believes as he did earlier that Gigantopithecus and H. erectus coexisted in the same environment--an argument he had made book in 1990 Other Origins: The Search for the Giant Ape in Human Prehistory.

Without the assumption that Gigantopithecus and H. erectus lived together, everything changed: if early humans were not part of the Stegodon–Ailuropoda fauna, I had to envision a chimpanzee-sized ape in its place — either a descendant of Lufengpithecus, or a previously unknown ape genus.

A key factor in changing in opinion was a visit in 2005 to the Guangxi Natural History Museum in Nanning where he examined a large number of primate teeth from the Pleistocene. He also feels that early humans did not live in subtropic forests that existed at Longgupo at that period.

Homo erectus, it seems from this perspective, hunted grazing mammals on open grasslands, and did not or could not penetrate the dense subtropical forest.

While Russell Ciochon no longer believes the jaw to belong to a human, he still claims the two stone tools found with them were made by humans. He according to him, "They must have been more recent additions to the site".

Jeffrey Schwartz one of the critics of the original claim that the jaw was human has been quoted as noting about Ciochon's retraction that it is "really astonishing. It is not often that a scientist says he changes his mind. This openness is good."

Nanjing Man (Homo erectus nankinensis) a subspecies of Homo erectus found in China. A male and a female skull of Nanjing Man were discovered in 1993 in Tangshan Cave near Nanjing, and they have been dated to be about 580,000 to 620,000 years old[1]. The skull is now preserved in Nanjing Museum and is under in-depth research by authoritative scientists in the field

Peking Man (Chinese: pinyin: Běijīng Yuánrén), also called Sinanthropus pekinensis (currently Homo erectus pekinensis), is an example of Homo erectus. A group of fossil specimens was discovered in 1923-27 during excavations at Zhoukoudian (Chou K'ou-tien) near Beijing (written 'Peking' before the adoption of the Pinyin romanization system), China. More recently, the finds have been dated from roughly 500,000 years ago, although a new 26Al/10Be dating suggests they may be as much as 680,000-780,000 years old.

Between 1929 and 1937, 15 partial craniums, 11 lower jaws, many teeth, some skeletal bones and large numbers of stone tools were discovered in the Lower Cave at Locality 1 of the Peking Man site at Zhoukoudian, near Beijing, in China. Their age is estimated to be between 500,000 and 300,000 years old. (A number of fossils of modern humans were also discovered in the Upper Cave at the same site in 1933.) The most complete fossils, all of which were braincases or skullcaps, are:

Skull III, discovered at Locus E in 1929 is an adolescent or juvenile with a brain size of 915 cc.

Skull II, discovered at Locus D in 1929 but only recognized in 1930, is an adult or adolescent with a brain size of 1030 cc.

Skulls X, XI and XII (sometimes called LI, LII and LIII) were discovered at Locus L in 1936. They are thought to belong to an adult man, an adult woman and a young adult, with brain sizes of 1225 cc, 1015 cc and 1030 cc respectively. (Weidenreich 1937)

Skull V: two cranial fragments were discovered in 1966 which fit with (casts of) two other fragments found in 1934 and 1936 to form much of a skullcap with a brain size of 1140 cc. These pieces were found at a higher level, and appear to be more modern than the other skullcaps. (Jia and Huang 1990) (Creationist arguments)

Most of the study on these fossils was done by Davidson Black until his death in 1934. Franz Weidenreich replaced him and studied the fossils until leaving China in 1941. The original fossils disappeared in 1941 while being shipped to the United States for safety during World War II, but excellent casts and descriptions remain. Since the war, other erectus fossils have been found at this site and others in China.

The illustration above is of a reconstruction done by Franz Weidenreich, based on bones from at least four different individuals (none of the fossils were this complete).

and American palaeontologist Walter W. Granger came to Zhoukoudian, China in search of prehistoric fossils in 1921. They were directed to the site at Dragon Bone Hill by local quarrymen, where Andersson recognised deposits of quartz that were not native to the area. Immediately realising the importance of this find he turned to his colleague and announced, "Here is primitive man, now all we have to do is find him!"

Excavation work was begun immediately by Andersson's assistant Austrian palaeontologist Otto Zdansky, who found what appeared to be a fossilised human molar. He returned to the site in 1923 and materials excavated in the two subsequent digs were sent back to Uppsala University in Sweden for analysis. In 1926 Andersson announced the discovery of two human molars found in this material and Zdansky published his findings.

Canadian anatomist Davidson Black of Peking Union Medical College, excited by Andersson and Zdansky’s find, secured funding from the Rockefeller Foundation and recommenced excavations at the site in 1927 with both Western and Chinese scientists. A tooth was unearthed that fall by Swedish palaeontologist Anders Birger Bohlin which Davidson placed in a locket around his neck.

Davidson published his analysis in the journal Nature, identifying his find as belonging to a new species and genus which he named Sinanthropus pekinensis, but many fellow scientists were skeptical of such an identification based on a single tooth and the Foundation demanded more specimens before they would give an additional grant.

A lower jaw, several teeth, and skull fragments were unearthed in 1928. Black presented these finds to the Foundation and was rewarded with an $80,000 grant that he used to establish the Cenozoic Research Laboratory.

Excavations at the site under the supervision of Chinese archaeologists Yang Zhongjian, Pei Wenzhong, and Jia Lanpo uncovered 200 human fossils (including 6 nearly complete skullcaps) from more than 40 individual specimens. These excavation came to an end in 1937 with the Japanese invasion.

Fossils of Peking Man were placed in the safe at the Cenozoic Research Laboratory of the Peking Union Medical College. Eventually, in November 1941, secretary Hu Chengzi packed up the fossils so they could be sent to USA for safekeeping until the end of the war. They vanished en route to the port city of Qinhuangdao.

Various parties have tried to locate the fossils, but so far they have been without result. In 1972, a US financier Christopher Janus promised a $5,000 (USD) reward for the missing skulls; one woman contacted him, asking for $500,000 (USD) but she later vanished. In July 2005, the Chinese government founded a committee to find the bones to coincide with the 60th anniversary of the end of World War II.

There are various theories of what might have happened, including a theory that the bones sank with the Japanese ship Awa Maru in 1945. Three of the teeth can, however, be found at the Paleontological Museum of Uppsala University.

Excavations at Zhoukoudian resumed after the war, and parts of another skull were found in 1966. To date a number of other partial fossil remains have been found. The Peking Man Site at Zhoukoudian was listed by UNESCO as a World Heritage Site in 1987. New excavations were scheduled to start at the site in the middle of May 2009.

The first specimens of Homo erectus had been found in Java in 1891 by Eugene Dubois, but were dismissed by many as the remains of a deformed ape. The discovery of the great quantity of finds at Zhoukoudian put this to rest and Java Man, who had initially been named Pithecanthropus erectus, was transferred to the genus Homo along with Peking Man.

Contiguous findings of animal remains and evidence of fire and tool usage, as well as the manufacturing of tools, were used to support H. erectus being the first "faber" or tool-worker. The analysis of the remains of "Peking Man" led to the claim that the Zhoukoudian and Java fossils were examples of the same broad stage of human evolution.

This interpretation was challenged in 1985 by Lewis Binford, who claimed that the Peking Man was a scavenger, not a hunter. The 1998 team of Steve Weiner of the Weizmann Institute of Science concluded that they had not found evidence that the Peking Man had used fire

Some Chinese paleoanthropologists[who?] have asserted in the past that the modern Chinese (and possibly other ethnic groups) are descendants of Peking Man. However, a recent study undertaken by Chinese geneticist Jin Li showed that the genetic diversity of modern Chinese people is well within that of the whole world population, which suggests there was no inter-breeding between modern human immigrants to East Asia and Homo erectus, such as Peking Man, and that the Chinese are descended from Africa, like all other modern humans, in accordance with the Recent single-origin hypothesis, the consensus among most modern scientists. However, the RRM2P4 gene data suggests that the Chinese, while largely descending from Africa like all other humans, nevertheless have some genetic legacy from hybridization with older Eurasian populations, consistent with limited multiregional evolution. Some paleontologists claim to see continuity in skeletal remains.

Homo antecessor is an extinct human species (or subspecies) dating from 1.2 million to 800,000 years ago, that was discovered by Eudald Carbonell, J. L. Arsuaga and J. M. Bermúdez de Castro. H. antecessor is one of the earliest known human varieties in Europe. Many anthropologists believe that H. antecessor is either the same species or a direct antecedent to Homo heidelbergensis, who inhabited Europe from 600,000 to 250,000 years ago in the Pleistocene.

The best-preserved fossil is a maxilla which belonged to a 10-year-old individual found in Spain. Based on palaeomagnetic measurements, it is thought to be older than 780-857 ka (Falguères et al., 1999:351). The average brain was 1000 cm³ in volume. In 1994 and 1995, 80 fossils of six individuals that may have belonged to the species were found in Atapuerca, Spain. At the site were numerous examples of cuts where the flesh had been flensed from the bones, which indicates that H. antecessor could have practised cannibalism.

Homo antecessor was about 1.6-1.8 m (5½-6 feet) tall, and males weighed roughly 90 kg (200 pounds). Their brain sizes were roughly 1000–1150 cm³, smaller than the 1350 cm³ average of modern humans. Due to its scarcity, very little more is known about the physiology of H. antecessor, yet it was likely to have been more robust than H. heidelbergensis. According to Juan Luis Arsuaga, one of the co-directors of the excavation in Burgos, H. antecessor might have been right-handed, a trait that makes them different from the other apes. The hypothesis is based on tomography techniques. Arsuaga also claims that the frequency range of audition is similar to H. sapiens' which makes him believe that H. antecessor used a symbolic language and was able to reason. Arsuaga's team is currently pursuing a DNA map of H. antecessor after elucidating that of a bear that lived in northern Spain some 500,000 years ago.

Basing on teeth eruption pattern, the researchers think that Homo antecessor had the same development stages as Homo sapiens, though probably at a faster pace. Other features acquired by the species are a protruding occipital bun, a low forehead and a lack of a strong chin. Some of the remains are almost indistinguishable from the fossil attributable to KNM-WT 15000 (Turkana Boy) belonging to Homo ergaster

The only known fossils of H. antecessor are from two sites in the Sierra de Atapuerca region of northern Spain (Gran Dolina and Sima del Elefante).

Archaeologist Eudald Carbonell i Roura of the Universidad Rovira i Virgili in Tarragona, Spain and palaeoanthropologist Juan Luis Arsuaga Ferreras of the Complutense University of Madrid discovered Homo antecessor remains at the Gran Dolina site in the Sierra de Atapuerca, east of Burgos. The H. antecessor remains have been found in level 6 (TF6) of the Gran Dolina site. Over 80 bone fragments from six individuals were uncovered in 1994 and 1995. The site had also included roughly 200 stone tools and about 300 animal bones. Stone tools including a stone carved knife were found along with the ancient hominin remains. All these remains were dated at least 780,000 years old. The best-preserved remains are a maxilla (upper jawbone) and a frontal bone of an individual who died at 10–11 years old.

On 29 June 2007, Spanish researchers working at the Sima del Elefante site announced that they had recovered a molar dated to 1.1–1.2 million years ago. The molar was described as "well worn" and from an individual between 20 and 25 years of age. Additional findings announced on 27 March 2008 included the discovery of a mandible fragment, stone flakes, and evidence of animal bone processing.

Homo ergaster is an extinct chronospecies of Homo that lived in eastern and southern Africa from the end of the Pliocene epoch to the early Pleistocene, about 1.8-1.3 million years ago. There is still disagreement on the subject of the classification, ancestry, and progeny of H. ergaster, but it is now widely thought (though not agreed) to be the direct ancestor of later hominids such as Homo heidelbergensis, Homo sapiens and Homo neanderthalensis rather than Asian Homo erectus. It is one of the earliest members of the genus Homo, possibly descended from, or sharing a common ancestor with, Homo habilis.

The binominal name published in 1975 by Groves and Mazák is derived from the Greek εργαστηρ "workman", in reference to the comparatively advanced lithic technology developed by the species, introducing the Acheulean industry.

S.A paleontologist John Robinson first discovered a mandible of a new hominid in southern Africa in 1949; he named the species Telanthropus capensis, though it is now recognised as a member of Homo ergaster. The name was first applied by Colin Groves and Vratislav Mazák to KNM-ER 992, a mandible discovered near Lake Rudolf (now Lake Turkana), Kenya in 1975, which became the type-specimen of the species. The most complete skeleton of H. ergaster (and one of the most complete extinct hominids to date), KNM-WT 15000, was discovered at Lake Turkana, Kenya, in 1984 by paleoanthropologists Kamoya Kimeu and Alan Walker. They nicknamed the 1.6-million-year-old specimen "Turkana Boy".

Many paleoanthropologists still debate the definition of H. ergaster and H. erectus as separate species. Some call H. ergaster the direct African ancestor of H. erectus, proposing that H. ergaster emigrated out of Africa and into Asia, branching into a distinct species. Most dispense with the species-name ergaster, making no distinction between such fossils as the Turkana Boy and Peking Man. Though "Homo ergaster" has gained some acceptance as a valid taxon, H. ergaster and H. erectus are still usually defined as distinct African and Asian populations of the larger species H. erectus. (For the remainder of this article, the name "Homo ergaster"will be used to describe a distinct species for the convenience of continuity in reading.)

H. ergaster may be distinguished from H. erectus by its thinner skull-bones and lack of an obvious supraorbital sulcus. It may be distinguished from Homo heidelbergensis by its thinner bones, more protrusive face, and lower forehead. Derived features separating it from earlier species include reduced sexual dimorphism, a smaller, more orthognathous (less protrusive) face, a smaller dental arcade, and a larger cranial capacity (700-900cm³ in earlier ergaster-specimens, and 900-1100 in later specimens). It is estimated that H. ergaster stood at 1.9 metres (6.2 ft) tall. Remains have been found in Tanzania, Ethiopia, Kenya, and South Africa.

is generally accepted as the putative ancestor of the genus Homo, and often of H. ergaster most directly. This taxon's status as a legitimate species within "Homo", however, is particularly contentious. H. habilis and H. ergaster coexisted for 200,000-300,000 years, possibly indicating that these species diverged from a common ancestor. It is unclear the genetic influence that H. ergaster had on later hominids. Recent genetic analysis has generally supported the Out-of-Africa hypothesis, and this may designate H. ergaster the role of ancestor to all later hominids

H. ergaster diverged from the lineage of H. habilis between 1.9 and 1.8 million years ago; the lineage that emigrated Africa and fathered H. erectus diverged from the lineage of H. ergaster almost immediately after this. These early descendants of H. ergaster may have been discovered in Dmanisi, Georgia.H. ergaster remained stable for ca. 500,000 years in Africa before disappearing from the fossil record around 1.4 million years ago. No identifiable cause has been attributed to this disappearance; the later evolution of the similar H. heidelbergensis in Africa may indicate that this is simply a hole in the record, or that some intermediate species has not yet been discovered.

Homo ergaster used more diverse and sophisticated stone tools than its predecessors: H. erectus. H. ergaster refined the inherited Oldowan developing the first Acheulean bifacial axes: while the use of Acheulean tools began ca. 1.6 million years ago, the line of H. erectus diverged some 200,000 years before the general innovation of Acheulean technology. Thus the Asian migratory descendants of H. ergaster made no use of any Acheulean technology.

Sexual dimorphism in H. ergaster is greatly reduced from its australopithecine ancestors (around 20%), but still greater than dimorphism in modern humans. This diminished competition for mates between males, implied by the reduction in sexual dimorphism, may also correspond to the more modern social practices of ergaster. Not only was H. ergaster like modern humans in body, but also more in organisation and sociality than any earlier species. It is conceivable that H. ergaster was the first hominin to harness fire: whether as the containment of natural fire, or as the lighting of artificial fire, is still a matter of contention. It is now assumed, however, that erectus did have control of fire, as well as each other hominin sharing a common ancestor with ergaster. The social organisation of H. ergaster probably resembled that of modern hunter-gatherer societies. Unlike australopithecines, ergaster males presumably did not compete at all for females, which had themselves increased in size greatly in proportion to males. This reduced competition and dimorphism also coincided with an increase in brain size and efficiency of stone tools.

Homo ergaster was probably the first hominid to "use a human voice",clarification needed] though its symbolic cognition was probably somewhat more[clarification needed] limited. It was thought for a long time that H. ergaster was restricted in the physical ability to regulate breathing and produce complex sounds. This was based on Turkana Boy's cervical vertebrae, which were far narrower than in later humans. Discoveries of cervical vertebrae in Dmanisi, Georgia some .3 million years older than those of Turkana Boy are well within the normal human range. It has been established, furthermore, that the Turkana Boy probably suffered from a disease of the spinal column that resulted in narrower cervical vertebrae than in modern humans (as well as the older Dmanisi finds). While the Dmanisi finds have not been established definitively as H. ergaster; they are older than Turkana Boy (the only definite ergaster-vertebrae on record), and thereby suggest kinship to ergaster. Turkana Boy, therefore, may be an anomaly.

There is no archaeological evidence that Homo ergaster made use of symbolic thought (such as figurative art), but the well evolved brain and physical capabilities (along with reconfiguration of ergaster's breathing-apparatus) suggest some form of linguistic or symbolic communication.