Homo erectus

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How to read a taxoboxHomo erectus
Fossil range: Pleistocene
Homo erectus pekinensisWeidenreich's Reconstruction
Homo erectus pekinensis
Weidenreich's Reconstruction
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Primates
Family: Hominidae
Genus: Homo
Species: H. erectus
Binomial name
Homo erectus
(Dubois, 1892)
Synonyms

Pithecanthropus erectus
Sinanthropus pekinensis
Javanthropus soloensis
Meganthropus paleojavanicus

Homo erectus ("upright man") is an extinct species of the genus Homo. It lived from about 1.8 million years ago (mya) to 50-70,000 years ago. However, often the early phase, from 1.8 to 1.25 (or 1.6) mya, is considered to be a separate species, Homo ergaster, or it is seen as a subspecies of H. erectus, Homo erectus ergaster (Mayr 2001). Although H. erectus was originally believed to have disappeared roughly 400,000 years ago, the dating of deposits thought to contain H. erectus fossils in Java were placed at only 50,000 years ago, meaning that at least one population would have been a contemporary of modern humans (Smithsonian 2007a).

Fossil findings of early hominids is often fragmentary and inferences speculative, and although fossils of Homo erectus are much more common and complete than those of Homo habilis, researchers are not even sure into how many species the fossils can be placed. Nonetheless, it is clear that Homo erectus was a major stage in the history of human evolution. Just as in the stage-by-stage development of individuals (egg, baby, child, adolescent, adult) and the history of life on Earth (Precambrian, Cambrian, Ordovician, etc.), Homo erectus served as a foundation for subsequent stages, and it is considered to have given rise to Neandertals and Homo sapiens (Mayr 2001). H. erectus is thought to have been the first human ancestor to walk truly upright.

Homo erectus was apparently very successful, considering that fossils of the species have been found in Africa, Asia (Indonesia and China), and Georgia (Caucasus region of Europe)(Mayr 2001). It is considered to be the first hominid to spread out of Africa. The differences between the early populations of H. erectus in Africa and the later populations found in Asia, Europe, and Africa are substantial enough for the separation by many researchers into the early African H. ergaster and the mainly Asian populations H. erectus (Smithsonian 2007b).

The first fossils of Homo erectus were discovered by Dutch physician Eugene Dubois in 1891 on the Indonesian island of Java. He originally gave the material the name Pithecanthropus erectus based on its morphology that he considered to be intermediate between that of humans and apes. A famous example of Homo erectus is Peking Man, unearthed in China.

Mayr (2001) notes that H. erectus existed without major change for at least one million years.

Contents

Overview

Fossilized remains, dating to as early as 1.8 million years ago, have been found in Africa (Lake Turkana, Kenya and Olduvai Gorge, Tanzania, among others), Europe (Georgia), Indonesia (e.g., Sangiran and Trinil), and China (e.g., Lantian). H. erectus utilized the natural corridor of the Great Rift Valley (northern Syria to Mozambique) to migrate to the Red Sea (Novaresio 1996).

Dutch anatomist Eugene Dubois (1890s) first described his finding as Pithecanthropus erectus, "ape-man who walked upright," based on a calotte (skullcap) and a modern-looking femur found from the bank of the Solo River at Trinil, in central Java. Thanks to Canadian anatomist Davidson Black's initial description of a lower molar, which was dubbed Sinanthropus pekinensis, most of the early and spectacular discovery of this taxon took place at Zhoukoudian in China. The first finding was in China was in 1921 and Black examined the tooth in 1926, reporting his findings in 1927. German anatomist Franz Weidenreich provided many of the detailed descriptions 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 City and at the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing.

Throughout much of the twentieth century, anthropologists have debated the role of H. erectus in human evolution. Early in the century, due to the discoveries on Java and at Zhoukoudian, it was believed that modern humans first evolved in Asia. This contradicted Charles Darwin's idea of African human origin. However, during the 1950s and 1970s, the numerous fossil finds from East Africa (Kenya) yielded evidence that the oldest hominins (members of the tribe Hominini: extinct and extant chimpanzees and humans) 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). H. erectus appears to originally have migrated from Africa during the Early Pleistocene around two million years ago, dispersing throughout most of the Old World.

H. erectus remains an important hominin since it is believed to be the first to leave Africa. In addition H. erectus was the first human ancestor to walk truly upright, which was made possible by the development of locking knees and a different location for the foramen magnum (the hole in the skull where the spine enters). They may have used fire to cook their meat. However, some scholars believe that H. erectus is an evolutionary lineage too derived—that is, too advanced—to have been the ancestor to modern H. sapiens.

Mayr (2001), however, states that "there is little doubt" that Neanderthals arose from the western populations of H. erectus and that Homo sapiens "clearly derived from African populations of H. erectus.

Description

Homo erectus has fairly derived morphological features, and a larger cranial capacity than that of Homo habilis, although new finds from Dmanisi in the Republic of Georgia show distinctively small crania. The forehead (frontal bone) is less sloping and the teeth are smaller (quantification of these differences is difficult, however).

Homo erectus would bear a striking resemblance to modern humans, but had a brain about 75 percent (950 to 1100 cc) of the size of that of a modern human. These early hominins were tall, on average standing about 1.79 m (5 feet, 10 inches). The sexual dimorphism between males and females is considered to have been almost the same as seen in modern Homo sapiens with males being slightly larger than females. The discovery of the skeleton KNM-WT 15000 (Turkana boy) made near Lake Turkana, Kenya by Richard Leakey and Kamoya Kimeu in 1984 was a breakthrough in interpreting the physiological status of H. erectus. KNM-WT 15000 is a nearly complete skeleton of an 11- or 12-year-old hominid boy who died 1.5 million years ago.

Tools and social aspects

Fossil evidence suggests that Homo erectus used more diverse and sophisticated tools than its predecessors. This has been theorized to have been a result of Homo erectus first using tools of the Oldowan style (sometimes called "core tools," "pebble tools," "bifaces," or "choppers") and later progressing to the Acheulean style (such as oval and pear-shaped handaxes). The surviving tools from both periods are all made of stone. Oldowan tools are the oldest known formed tools and date as far back as about 2.4 million years ago. The Acheulean era began about 1.2 million years ago and ended about 500,000 years ago. The primary innovation associated with Acheulean handaxes is that the stone was chipped on both sides to form two cutting edges.

Homo erectus (along with Homo ergaster) were probably the first early humans to fit squarely into the category of a hunter gatherer society and not as prey for larger animals. Anthropologists such as Richard Leakey believe that H. erectus was socially closer to modern humans than the more primitive species before it. The increased cranial capacity generally coincides with the more sophisticated tool technology occasionally found with the species' remains.

The discovery of Turkana boy has shown evidence that despite the human-like anatomy of H. erectus, they were not capable of producing sounds of a complexity comparable to modern speech.

Early humans, in the person of Homo erectus, were learning to master their environment for the first time. Attributed to H. erectus, around 1.8 million years ago in the Olduvai Gorge, is the oldest known evidence of mammoth consumption (Levy 2006). Bower (2003) has suggested that H. erectus may have built rafts and traveled over oceans, although this possibility is considered controversial.

Some dispute that H. erectus was able to control fire. However, the earliest (least disputed) evidence of controlled fire is around 300,000 years old and comes from a site called Terra Amata, which lies on an ancient beach location on the French Riviera. This site seems to have been occupied by Homo erectus. There are older Homo erectus sites that seem to indicate controlled use of fire, some dating back 500,000 to 1.5 million years ago, in France, China, and other areas. A discovery brought forth at the Paleoanthropology Society annual meeting in Montreal, Canada in March of 2004 stated that there is evidence for controlled fires in excavations in northern Israel from about 690,000 to 790,000 years ago. Regardless, it can at least be surmised that the controlled use of fire was atypical of Homo erectus until its decline and the rise of more advanced species of the Homo genus came to the forefront (such as Homo antecessor. H. heidelbergensis and H. neanderthalensis).

Classification

There has almost always been a great deal of discussion concerning the taxonomy of Homo erectus, and it relates to the question of whether or not H. erectus is a geographically widespread species (found in Africa, Europe, and Asia), or a classic Asian lineage that evolved from less cranially derived African H. ergaster. Kreger (2005) notes that some also split into three groups, "Asian and later African material remaining as erectus (with erectus not contributing to modern humans), early African material as ergaster, and European material as heidelbergensis."

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.

Homo erectus

    • Homo erectus yuanmouensis
    • Homo erectus lantianensis
    • Homo erectus pekinensis
    • Homo erectus palaeojavanicus
    • Homo erectus soloensis

Other species

The recent discovery of a fossil ascribed to a new species, Homo floresiensis, listed as 18,000 years ago, has raised the possibility that numerous descendant species of Homo erectus may have existed in the islands of southeast Asia that await fossil discovery. However, some scientists are skeptical about the claim that Homo floresiensis is a descendant of Homo erectus or that it is anything other than Homo sapiens. One theory holds that the fossils are from a modern human with microcephaly (disorder resulting in a smaller head), while another one claims that they are from a group of pygmys.

Individual fossils

Some of the major Homo erectus (or Homo ergaster in the case of those ancient fossils from Africa):

  • Indonesia (island of Java): Trinil 2 (holotype), Sangiran collection, Sambungmachan collection, Ngandong collection
  • China: Lantian (Gongwangling and Chenjiawo), Yunxian, Zhoukoudian, Nanjing, Hexian
  • India: Narmada (taxonomic status debated!)
  • Kenya: WT 15000 (Nariokotome), ER 3883, ER 3733
  • Tanzania: OH 9
  • Republic of Georgia: Dmanisi collection

References

  • Bower, B. 2003. Erectus ahoy: Prehistoric seafaring floats into view. Science News Online 164(16):248.
  • Kreger, C. D. 2005. Homo erectus: Introduction. Archaeology.info. Retrieved March 4, 2007.
  • Levy, S. 2006. Clashing with titans. BioScience 56(4): 295.
  • Mayr, E. 2001. What evolution is. New York: Basic Books. ISBN 0465044255.
  • Novaresio, P. 1996. The Explorers. Stewart, Tabori & Chang. ISBN 155670495X.
  • Sawyer, G. J., and B. Maley. 2005. Neanderthal Reconstructed. Anat. Rec. (New Anat.) 283B: 23-31.
  • Smithsonian National Museum of Natural History. 2007a. Homo erectus. Smithsonian Institution. Retrieved March 4, 2007.
  • Smithsonian National Museum of Natural History. 2007b. Homo ergaster. Smithsonian Institution. Retrieved March 4, 2007.
  • Tattersall, I., and J. Schwartz. 2000. Extinct Humans. Boulder, CO: Westview Press. ISBN 0813334829.

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