Homo erectus () is an extinct species of the genus
Homo, which originated in
Africa and spread as far as
China and
Java. Depending on the definition of the species, it is considered to be either a direct ancestor of modern humans, or a separate species which co-existed with the distinct
Homo neanderthalensis and a third branch which is a direct ancestor of modern humans.
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).
Classification
KNM-ER 3883 replica
There has been a great deal of discussion concerning the taxonomy of
Homo erectus (see the 1984 and 1994 volumes of Courier Forschungsinstitut Senckenberg):
H. erectus may be geographically widespread species (found in Africa, Europe, and Asia), or a classic Asian lineage that evolved from the distinct African
Homo ergaster.
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 different extant primate groups 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 as two different species. Of course, the extant model (of comparison) is very important and choosing the proper 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 diversity may not be a trustworthy comparison.)
Many
paleoanthropologists still debate the definition of
H. erectus and
H. ergaster as separate species. Some, such as
Ian Tattersall, divide
H. ergaster on the basis of cranial features and geographical distribution as a separate species. Tatersall calls
H. ergaster the direct African ancestor of
H. erectus, proposing that
H. ergaster emigrated out of Africa into Asia, where it had already become distinct enough from its African ancestors as to be classified as a disparate species. Others, such as
Richard Leakey, call both the
Peking Man and the
Turkana Boy Homo erectus.
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 homo erectus and it's ancestor,
homo habilis, thus showing that hominid migration out of Africa had occurred before the evolution of homo erectus.
History of discoveries
Homo erectus tautavelensis skull
Dutch anatomist
Eugene Dubois was fascinated with
Charles Darwin's theories on evolution, so set out to find an early human (1890s). He first described the species as
Pithecanthropus erectus ("upright ape-man"), based on a calotte (skullcap) and a femur like that of
Homo sapiens found from the bank of the
Solo River at
Trinil, in
East Java. (This species is now regarded as Homo erectus.) His find is commonly referred to as
Java Man. However, thanks to Canadian anatomist
Davidson Black's (1921) initial description of a lower molar, which was dubbed
Sinanthropus pekinensis, 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). However, nearly all of the original specimens were lost during
World War II. High quality Weidenreichian casts do exist and are considered to be reliable evidence; these are curated at the
American Museum of Natural History in
New York and at the
Institute of Vertebrate Paleontology and Paleoanthropology in
Beijing.
Throughout much of the 20th century, anthropologists debated the role of
H. erectus in
human evolution. Early in the century, due to discoveries on Java and at Zhoukoudian, it was believed that modern humans first evolved in Asia. A few naturalists, most prominent among them Charles Darwin, predicted that humans' earliest ancestors were African (referring only to the fact that chimps and gorillas, obvious human relatives, live only in Africa). Most naturalists of the time had disregarded this. During the 1950s and 1970s, however, numerous fossil finds from East Africa (
Kenya) yielded evidence that the oldest
hominins originated there. It is now believed that
H. erectus is a descendant of earlier hominins such as
Australopithecus and early
Homo species (e.g.,
H. habilis), although there is a contrary view that
H. habilis and
H. erectus coexisted and may be separate lineages from a common ancestor.
A skull,
Tchadanthropus uxoris, discovered in 1961, is the partial skull of the first early
hominid discovered in
Central Africa, found in
Chad during an expedition led by the
anthropologist Yves Coppens.
While some then thought it was a variety of
Homo habilis,
is no longer considered to be a separate species, and scholars consider it to be
Homo erectus.
Description
Homo erectus had a cranial capacity greater than that of Homo habilis, although the Dmanisi finds show distinctively small crania. The forehead (frontal bone) is less sloped and the teeth are smaller (quantification of these differences is difficult, however; see below). The face is more orthognatic than either the Australopithecines or H. habilis, with large brow-ridges and less prominent zygomata (cheekbones). The earliest remains show a cranial capacity of 850 cm³ while the latest Javan specimina measure up to 1100 cm³ [Java Man, Curtis, Swisher and Lewin, ISBN 0349114730.], overlapping that of H. sapiens. These early hominins stood about , and were more robust than modern humans.Tool Use
Homo ergaster used more diverse and sophisticated 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. The use of Acheulean tools began ca. 1.6 million years ago, though the H. erectus line 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. The primary innovation associated with Acheulean handaxes is that the stone was chipped on both sides to form a biface of two cutting edges. In addition it has been suggested that Homo erectus may have been the first hominid to use rafts to travel over oceans, though no consensus has been reached.Sociality
A reconstruction of
Homo erectus at the Westfälisches Museum für Archäologie,
Herne, Germany
The discovery of Turkana boy in 1984 gave evidence that despite H. erectus's human-like anatomy, they may not have been capable of producing sounds comparable to modern human speech. They 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. This viewpoint has been challenged by the discovery of H. ergaster/erectus vertebrae (some 150,000 years older than the Turkana Boy) in Dmanisi, Georgia that may 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.
The most recent populations of H. erectus were probably the first hominid societies to live in small scale band societies similar to modern hunter gatherer band societies. Homo erectus is thought to be the first hominid to hunt in coordinated groups, use complex tools, and care after infirm or weak companions.
H. erectus lived throughout the Great Rift Valley, as far north as the Red Sea. The oldest known evidence of mammoth consumption by hominids has been attributed to H. erectus, around 1.8 million years ago in the Olduvai Gorge. Bruce Bower has suggested that H. erectus may have built rafts and traveled over oceans, although this possibility is considered controversial.
Sites in France, China, Vietnam, and other areas 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 good 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 start fire. Despite these examples, some scholars continue to assert that the controlled use of fire was not typical of Homo erectus, but only of later species of the Homo genus, such as Homo antecessor, H. heidelbergensis and H. neanderthalensis).
H. erectus, and possibly the later Neanderthals may have interbred with modern humans in Europe and Asia, though genetic evidence largely does not support this theory. Descendants and subspecies
Homo erectus remains one of the most successful and long-lived species of the Homo genus. It is generally considered to have given rise to a number of descendant species and subspecies. The oldest known specimen of the ancient human was found in southern Africa.
thumb|300px|Homo erectus and its progeny.
Other species
The discovery of Homo floresiensis and of the recentness of its extinction has raised the possibility that numerous descendant species of Homo erectus may have existed in the islands of Southeast Asia which await fossil discovery (see Orang Pendek). Some scientists are skeptical about 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 pygmys. Individual fossils
Original fossils of
Pithecanthropus erectus (now
Homo erectus) found in
Java in 1891
- Indonesia (island of Java): Trinil 2 (holotype), Sangiran collection, Sambungmachan collection, Ngandong collection
- India: Narmada (taxonomic status debated!)
- Kenya: WT 15000 (Nariokotome), ER 3883, ER 3733
- Vietnam: Northern, Tham Khuyen, Hoa Binh
- Republic of Georgia: Dmanisi collection
See also
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