Homo erectus (meaning “upright man,” from the Latin ērĭgĕre, “to put up, set upright”) is an extinct species of hominin that lived from the end of thePliocene epoch to the later Pleistocene, with the earliest first fossil evidence dating to around 1.8 million years ago and the most recent to around 143,000 years ago. The species originated in Africa and spread as far as England, Georgia, India, Sri Lanka, China and Java.
There is still disagreement on the subject of the classification, ancestry, and progeny of H. erectus, with two major alternative classifications: erectusmay 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.
Some palaeoanthropologists consider H. ergaster to be simply the African variety of H. erectus. This leads to the use of the term “Homo erectus sensu stricto” for the Asian H. erectus, and “Homo erectus sensu lato” for the larger species comprising both the early African populations (H. ergaster) and the Asian populations.
The first hypothesis is that H. erectus 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 theOld World. Fossilized remains 1.8 to 1 million years old have been found in Africa (e.g., Lake Turkana andOlduvai Gorge), Georgia, Europe (Spain), Indonesia (e.g., Sangiran in Central Java and Trinil in East Java),Vietnam, China (e.g., Shaanxi) and India.
The second hypothesis is that H. erectus evolved in Eurasia and then migrated to Africa. The species occupied a Caucasus site called Dmanisi, in Georgia, from 1.85 million to 1.77 million years ago, at the same time or slightly before the earliest evidence in Africa. Excavations found 73 stone tools for cutting and chopping and 34 bone fragments from unidentified creatures.
Many paleoanthropologists still debate the definition of H. erectus and H. ergaster as separate species. Several scholars suggested dropping the taxon Homo erectus and instead equating H. erectus with the archaic H. sapiens. Some call H. ergaster the direct African ancestor of H. erectus, proposing that it emigrated out of Africa and immigrated to 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. Although “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 small, and our own special diversity may not be a trustworthy comparison). As an example, fossils found inDmanisi in the Republic of Georgia were originally described as belonging to another closely related species, Homo georgicus, but subsequent examples showed their variation to be within the range of Homo erectus, and they are now classified as Homo erectus georgicus.
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 in), (Only 17 percent of modern male humans are taller) and were extraordinarily slender, with long arms and legs.
The sexual dimorphism between males and females was slightly greater than seen in H. sapiens, with males being about 25% larger than females. However, their dimorphism is drastically lesser than that of the earlier Australopithecus genus. 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.
USE of TOOLS
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. 1.8 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.
Use of fire
Sites in Europe and Asia seem to indicate controlled use of fire by H. erectus, dating back at least 1 million years. A presentation at the Paleoanthropology Society annual meeting inMontreal, Quebec 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 evidence of controlled fire, dated at around 300,000 years ago.
Excavations dating from approximately 790,000 years ago in Israel suggest that H. erectus not only controlled fire but could light fires. Finally, evidence from a site in the Northern Cape Province of South Africa is consistent with controlled fire use by H. erectus one million years ago. 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).
Homo erectus remains one of the most long-lived species of Homo, having existed over a million years, while Homo sapiens has so far existed for 200,000 years. As a distinct Asian species, however, no consensus has been reached as to whether it is ancestral to H. sapiens or any later hominids.
Previously Referred Taxa
The discovery of Homo floresiensis in 2003 and of the recentness of its extinction has raised the possibility that numerous descendant species of Homo erectus may have existed in the islands ofSoutheast Asia and await fossil discovery (see Orang Pendek). Homo erectus soloensis, who was long assumed to have lived on Java at least as late as about 50,000 years ago but was re-dated in 2011 to a much higher age, would be one of them. Some scientists are skeptical of the claim that Homo floresiensis is a descendant of Homo erectus. One explanation holds that the fossils are of a modern human with microcephaly, while another one holds that they are from a group of pygmies.