(01) H. erectus | The Smithsonian Institution's Human ... · (01) H. erectus | The Smithsonian...

(01) H. erectus | The Smithsonian Institution's Human Origins Program

Homo erectus

Where Lived: Where Lived: Northern, Eastern, and SouthernAfrica; Western Asia (Dmanisi, Republic ofGeorgia); East Asia (China and Indonesia)

When Lived: When Lived: Between about 1.89 million and143,000 years ago

Early African Homo erectus fossils (sometimes called Homo ergaster) are the oldestknown early humans to have possessed modern human-like body proportionswith relatively elongated legs and shorter arms compared to the size of the torso. Thesefeatures are considered adaptations to a life lived on the ground, indicating the loss ofearlier tree-climbing adaptations, with the ability to walk and possibly run long distances.Compared with earlier fossil humans, note the expanded braincase relative to the size of theface. The most complete fossil individual of this species is known as the ‘Turkana Boy’ – awell-preserved skeleton (though minus almost all the hand and foot bones), dated around1.6 million years old. Microscopic study of the teeth indicates that he grew up at a growthrate similar to that of a great ape. There is fossil evidence that this species cared for old andweak individuals. The appearance of Homo erectus in the fossil record is often associatedwith the earliest handaxes, the first major innovation in stone tool technology.

Early fossil discoveries from Java (beginning in the 1890s) and China (‘Peking Man’,beginning in the 1920s) comprise the classic examples of this species. Generally consideredto have been the rst species to have expanded beyond Africa, Homo erectus is considereda

Homo erectus | The Smithsonian Institution's Human Origins Program

http://humanorigins.si.edu/evidence/human-fossils/species/homo-erectus


highly variable species, spread over two continents (it's not certain whether it reachedEurope), and possibly the longest lived early human species - about nine times as long asour own species, Homo sapiens, has been around!

Year of Discovery: Year of Discovery: 1891

History of Discovery: History of Discovery: Eugène Dubois, a Dutch surgeon, found the rst Homo erectus individual (Trinil 2) inIndonesia in 1891. In 1894, Dubois named the species Pithecanthropus erectus, or ‘erectape-man.’ At that time, Pithecanthropus (later changed to Homo) erectus was the mostprimitive and smallest-brained of all known early human species; no early human fossilshad even been discovered in Africa yet.

Height: Height: Ranges from 4 ft 9 in - 6 ft 1 in (145 - 185 cm)

Weight: Weight: Ranges from 88 - 150 lbs (40 - 68 kg)

We don’t know everything about our early ancestors—but we keep learning more!Paleoanthropologists are constantly in the eld, excavating new areas, usinggroundbreaking technology, and continually lling in some of the gaps about ourunderstanding of human evolution.

Below are some of the still unanswered questions about Homo erectus that may beanswered with future discoveries:

Was Homo erectus the direct ancestor of Homo sapiens, our own species?Data suggest that increasing body size, greater reliance on animal food resources, and

increased range size were part of a web of factors that facilitated the initial early dispersal ofH. erectus from Africa. Was one of these factors more important than the others?

Are the fossils from earlier time periods in East Africa, and from Georgia, all part of asingle species (Homo erectus), regionally variable in size and shape? Or are there actuallyseveral species of early human represented by what we are now calling Homo erectus?




How well did Homo erectus master the control of re and how widespread was reused? What does this say about possible dietary shifts in this species?

Did Homo erectus grow up in a more human-like pattern and rate, or a more ape-likeone? Was Homo erectus the rst early human species to experience an adolescent growthspurt?

First paper:

Dubois, E.,. 1894. Pithecanthropus erectus: eine menschenaehnlich Uebergangsform ausJava. Batavia: Landsdrukerei.

Other recommended readings:

Antón, S.C., 2003. Natural history of Homo erectus. Yearbook of Physical Anthropology46, 126–170.

Le Gros Clark W.E., 1964. The fossil evidence for human evolution, 2nd ed. Chicago:University of Chicago Press.

Leonard, W.R., Robertson, M.L., 1997. Comparative primate energetics and hominidevolution. American Journal of Physical Anthropology 102, 265–281.

Mayr, E., 1950. Taxonomic categories of fossil hominids. Cold Spring Harbor SympQuant Biol 25, 109–118.

How They Survived: How They Survived: The tall bodies and large brains of Homo erectus individuals required a lot of energy on aregular basis to function. Eating meat and other types of protein that could be quicklydigested made it possible to absorb nutrients with a shorter digestive tract, making moreenergy available faster. There is also speculation that honey and underground tubers mayhave been significant food sources for Homo erectus.




Soon after we see evidence in the fossil record of the earliest Homo erectus fossils (by about1.9 million years ago), we see evidence in the archeological record for the rst majorinnovation in stone tool technology (by about 1.76 million years ago). Known as theAcheulean stone tool industry, it consisted of the creation of large cutting tools likehandaxes and cleavers. Increased reliance on a broader set of tools may have helped Homoerectus survive during changing climates.

The earliest evidence of hearths (camp res) occur during the time range of Homo erectus.While we have evidence that hearths were used for cooking (and probably sharing) food,they are likely to have been places for social interaction, and also used for warmth and tokeep away large predators.

Evolutionary Tree Information: Evolutionary Tree Information: Some scientists distinguish between the African (Homo ergaster) and Asian (Homo erectussensu stricto) fossils of this taxon, while others lump them together as Homo erectus sensulato. In either case, there is general agreement that it descended from an earlier species ofHomo (e.g., Homo habilis) and represents one of the widest dispersals of early humans inour evolutionary history. It is likely that distinct populations of Homo erectus sensu latoled to the emergence of later hominin species, such as Homo heidelbergensis, andultimately to our own species, Homo sapiens.

At the beginning of its time range, around 1.9 Mya, H. erectus coexisted in East Africawith several other early human species including Homo rudolfensis, Homo habilis, andParanthropus boisei. Sometimes they were even found at the same fossil sites. At the end ofits time range, around 143,000 years ago, it coexisted with Homo sapiens and possiblyHomo floresiensis in Indonesia.



https://australianmuseum.net.au/image/Peking-Man-Homo-erectus-skull/

(02) Homo erectus - Australian Museum

Fossils of these short and stocky humans, with their distinctive skull shape and large browridges...

‘Peking Man’ Homo erectus skull Photographer: Stuart Humphreys © Australian Museum

...have mostly been found in China and Indonesia.

Fossils of these short and stocky humans, with their distinctive skull shape and large browridges, have mostly been found in China and Indonesia.

Debate abounds as to whether the Asian fossils and those from Africa should be classi edtogether as Homo erectus or if the African examples are di erent enough to be calledHomo ergaster. The information on this page refers specifically to Asian Homo erectus.

Background on discoveryAge

This species lived between 100,000 and 1.6 million years ago, although some estimatesextend this to between 35,000 and 1.8 million years ago.

Homo erectus - Australian Museum

https://australianmuseum.net.au/homo-erectus


Important fossil discoveries

After years of searching Indonesia for ‘the missing link’, Dutchman Eugene Dubois nallyuncovered part of a skull in 1891 (known as ‘Java Man’). He believed this fossil belongedto an ancient and ‘upright’ human and so coined the species name erectus. Other scientistsdismissed this interpretation, preferring to emphasise its ape-like qualities. Dubois’ opinionwas validated when a series of similar fossils were uncovered in China during the 1920sand 1930s.

Important specimens

Sangiran 17 – a 1.2 million-year-old skull discovered in 1969 in Sangiran, Indonesia.This adult male skull is the best preserved Homo erectus skull from Java. Zhoukoudian 3 – a skullcap discovered in 1929 in Zhoukoudian, China. Thisadolescent’s skullcap was originally found in fragments. When the pieces were ttedtogether, they showed that this young individual had a brain size of 915 cubiccentimetres. ‘Java Man’ or Trinil 2 – a skullcap discovered in 1891 by Eugene Dubois in Trinil,Indonesia. This fossil was nicknamed ‘Java Man’ because it was found on the island ofJava. It is the ‘type specimen’ or official representative for the species.

Sangiran 2 – a 1 million-year-old skullcap discovered in 1937 in Sangiran, Indonesia ‘Solo Man’ or Ngandong – a skull cap discovered in 1932 in Ngandong, Indonesia.Because its exact original location is unknown, published dates have ranged from35,000 to 500,000 years old. ‘Solo Man’ shares similarities with earlier Homo erectusspecimens from Sangiran and is considered to be a late Homo erectus. ‘Mojokerto’ or Perning 1 – a juvenile skull discovered in 1936 in Mojokerto,Indonesia. Radiometric dates have suggested this child’s skull may be as old as 1.8million years, which signi cantly increases the previous dates for Homo erectus inAsia. However, this date is debated as the sediment sample taken for dating was takenabout 60 years after the skull was collected and the two may have come from di erentlevels.




Zhoukoudian 5 – a partial skull discovered in Zhoukoudian, China. This skull wasreconstructed from several pieces found in 1934, 1936 and 1966. ‘Peking Man’ discovered in Zhoukoudian, China. The original ‘Peking Man’ skullwas reconstructed using a mixture of male and female fossils whereas the modernreconstruction by I. Tattersal and G. Sawyer combines fossil pieces from males only. Sangiran 4 – a 1.5 million-year-old upper jaw discovered in 1939 in Sangiran,Indonesia. The canine teeth were larger than those found in modern humans. This isone of the oldest specimens from Sangiran. Sangiran 1 – a 1.5 million-year-old partial lower jaw discovered in 1936 in Sangiran,Indonesia. This is the first human fossil discovered at Sangiran.

What the name means

Homo, is a Latin word meaning ‘human’ or ‘man’ and is the genus or group name of thisspecies.

The second word in this species’ scienti c name is erectus. This name was selected toindicate that this species’ ability to stand and walk with an upright or erect stance.

Distribution

Homo erectus is now one of the better known of our human relatives with over 40specimens excavated from Java and many more from sites in China.

Sangiran on the island of Java, is the most important Homo erectus site in Indonesia. Theremains of over 80 individuals have been found here at a number of localities. The regionwas first occupied about 1.6 million years ago.

The site of Zhoukoudian, 40 kilometres south of Beijing in China, has yielded the largestnumber of Homo erectus fossils from any one locality (about 50 individuals arerepresented by the remains). About 100,000 stone tool artefacts were also in the cave.These were mostly quartz and sandstone chopping tools and akes. It was occupiedbetween 200,000 and 750,000 years ago, although evidence suggests that occupation wassporadic rather than permanent. Hyenas and other animals also used the cave site.




Initial excavations between 1926 and 1937 yielded ve skullcaps, various other skullfragments, 11 jaws and more than 140 teeth. Almost all of these fossils were lost in 1941when the Japanese invaded China during World War II. Fortunately, accurate replicas ofthese fossils had been made. Additional Homo erectus fossils were excavated atZhoukoudian after World War II and have also been excavated since from Chinese sitesincluding Hexian, Lantian and Nanjing.

Relationships with other speciesA growing number of scientists have rede ned the species Homo erectus so that it nowcontains only east Asian fossils. Many of the older African fossils formerly known asHomo erectus have now been placed into a separate species, Homo ergaster and this speciesis considered to be ancestral to Homo erectus. The rede ned Homo erectus is nowgenerally believed to be a side branch on our family tree whereas Homo ergaster is nowviewed as one of our direct ancestors.

However, some scientists still support the view that all these specimens are Homo erectusand that this species includes individuals that vary in their features and have a widespreaddistribution over both time and geographic location.

There is even debate about whether the two Asian H.erectus populations represent thesame species. Prior to the 1950s the fossils from Java were known as Pithecanthropuserectus and those from China were called Sinanthropus pekinensis. Many early nds alsohad nicknames taken from the places they were found, such as ‘Peking Man’, ‘Java Man’,and ‘Solo Man’. In the 1950s they were all placed in the one species, Homo erectus, butsome scientists still believe the specimens represent di erent species or subspecies and usethe name Homo pekinensis for the Chinese fossils.

Even if the populations in Indonesia and China were the same species, the idea is nowbeing proposed that the populations were not connected, and that the Chinese populationarrived later than the Indonesian and came from a di erent source. Initially, itwas believed that the Asian H.erectus originated with one group that dispersed from asingle source in Africa.




Key physical featuresThis species had a robust skeleton that was generally similar to those of modern humans.However, the skulls of Homo erectus were quite different to those of modern humans.

Body size and shape

the body (known only from the Chinese specimens) tended to be shorter and stockier thanthose of modern humans.

Brain

showed an increase in size over earlier species and averaged about 1050 cubiccentimetres structure of the brain was similar to that of modern humans

Skull

face was large with a low, sloping forehead, a massive brow ridge and a broad, atnose skull was broad and long with sharp angles at the rear, unlike the curve found inmodern humans bones of the skull were very thick and formed a small central ridge, known as amidline keel, along the top of the skull

Jaws and teeth

jaw was large and thick without a pointed chin molar teeth had large roots but were decreasing toward a more modern size

Limbs

limbs were like those of modern humans although the bones were thicker, suggestinga physically demanding lifestyle.




LifestyleCulture

The oldest known stone tools used by Homo erectus were made in China about onemillion years ago. These tools were simple choppers and akes (Mode 1 technology). Toolsgradually became smaller over time and came to include a greater variety of designs. Morecomplex bifacial tools (Mode 2 technology) like those made by Homo heidelbergensispeople from Eurasia made a limited appearance in parts of northern China. This mayindicate a brief period of contact between these different peoples.

Relatively few stone tools have been found in east Asia compared with western Asia, Africaand Europe but tools made from non-durable materials such as bamboo may have beenmanufactured instead.

Burnt stones and animal bones, charcoal and ash deposits indicate these people may haveused re about 500,000 years ago but it is di cult to prove whether this use wascontrolled.

Environment and diet

China underwent signi cant climatic changes during the period that Zhoukoudian wasoccupied. These changes included three cold glacial periods with harsh, wintertemperatures. The cooling and drying that occurred in these glacial periods brought anexpansion of open habitats, with grasslands and mixed steppes. These environmentsfavoured large grazing animals, which would have been hunted by Homo erectus.

Java, on the other hand, had a warmer climate. Low sea levels about 1.6 million years ago(when this area was rst occupied by H.erectus) may have seen Indonesia joined tomainland southeast Asia.

The remains of meals have been found at some Homo erectus sites in China. These showthat they ate large amounts of meat supplemented with plant foods and, in general, had adiet similar to that of early modern humans.



(03) Homo erectus | Becoming Human

Remains of Homo erectus are found throughout Africa and in western and eastern Asia(as far east as the island of Java in Indonesia). Other fossils, assigned by some scholars tothis species, have been found in Europe, as far north as England. Homo erectus had a longtenure; the earliest Homo erectus fossils are dated to roughly 1.8 million years ago, whilethe youngest fossils assigned to this species date to roughly 300 thousand years ago (ka). Homo erectus is important to the study of human evolution because it is the rst species tobe found outside of Africa and displayed many anatomical features (especially brain sizeand aspects of the postcranial skeleton—i.e., the parts of the skeleton below the head) thatreflect evolution toward the pattern seen in Homo sapiens.

The taxonomy (the naming and assignment of species) of Homo erectus is controversial. Some scholars maintain that important di erences exist between the Asian and Africanrepresentatives of this species. In particular, these scientists contend that features in thecranium (skull minus lower jaw)—e.g., large teeth, sagittal keels (narrow areas of thickenedbone extending from just behind the brows to the back of the skull) and massiveness of theneurocranium (the part of the skull that covers and protects the brain) and face—are foundonly in Asian H. erectus fossils. To these paleoanthropologists, this evidence suggests thatthe Asian and African sample represent separate species; the name ‘Homo ergaster’ is givento the African fossils to formalize this species-level distinction. However, as other scholarsargue, many of these traits are also found in some H. erectus fossils in Africa, suggestingthat the entire sample constitutes a single species, Homo erectus. On this website (and forthe remainder of this essay), the latter interpretation will be employed—i.e., ‘Homoerectus’ will be used to describe the entire sample (African and Asian).

Many of the features that distinguish Homo erectus from other hominin species—bothearlier and later species—are seen in the skull. The average brain size of Homo erectus isestimated to have been roughly 900 cubic centimeters (cc.), which is larger than Homohabilis, but smaller than that of Homo heidelbergensis and other later forms. The size ofthe Homo erectus brain is negligibly larger than in Homo habilis when it is considered asin relation to body size—i.e., brain size increased substantially in Homo erectus, but,because body size also increased, the relative size of the Homo erectus brain is notconsiderably larger than that of Homo habilis. The absolute in brain size, however, caused

Homo erectus | Becoming Human

http://www.becominghuman.org/node/homo-erectus-0


changes in the brain case; for instance, the braincase is higher than in Homo habilis, butlower than in later hominin species. The Homo erectus braincase is also very long relativeto its height, giving the skull a football-shape when viewed from the side. The braincaseand the face and jaws of Homo erectus were very heavily built, with thick bones andextreme thickenings along some of the skull sutures (where two skull bones connect). Forinstance, the browridges were massively built and continuous across the face and large,bony prominences existed in the back of the skull (the occipital torus and angular torus). Due to these prominences, the cranium of Homo erectus is pentagon-shaped when viewedfrom behind, with the widest area coinciding with the bottom of the cranium.

In addition to their use to de ne the species, cranial remains have also been used to studythe way that Homo erectus grew and developed into adulthood. Despite extensive study,scholars disagree about how the evidence bearing on this subject should be interpreted. Evidence from the teeth of Homo erectus fossils suggests that Homo erectus had not yetevolved the unique growth schedule exhibited by Homo sapiens. Using evidence fromfossil crania, however, some scientists contend that H. erectus possessed otherwiseuniquely human features, such as the juvenile growth spurt. Thus, it is currently unclearif the growth pattern found in Homo sapiens evolved in Homo erectus or in a later species.

The postcranial remains of this taxon have traditionally been interpreted as being verysimilar to those of Homo sapiens. The only notable di erence is that the postcranialremains of Homo erectus are generally thicker and more massively-built than those of H.sapiens; all other features, though, point to striking similarities between the two species.The stature of Homo erectus, for example, has been suggested to be very similar to livinghumans and the hindlimb (leg) of Homo erectus is much longer than in earlier forms forwhich good evidence exists. Therefore, the proportion of the hind- to forelimb length (legto arm) in Homo erectus is considered to be almost identical to that of Homo sapiens.Because of these similarities, most scholars believe that Homo erectus was the rst homininspecies that was capable of a bipedal form of locomotion indistinguishable from that ofHomo sapiens. Recent research, however, suggests that key fossils assigned to Homoerectus were much shorter than previously thought and argues that modern human staturemay not have been present in Homo erectus. To wit, recent fossil finds in Kenya suggest




that Homo erectus was quite variable in size and that sexual dimorphism (di erencesbetween males and females within a species) may have been greater than previouslybelieved.

Whether it was due to its possession of human-like gait or not, Homo erectus is the rsthominin species to have been found outside of Africa. Many sites bearing Homo erectusfossils have been discovered in China and Indonesia. In general, these sites are later thanHomo erectus sites in Africa. At a site called Dmanisi in the Republic of Georgia,however, fossil assigned to Homo erectus have been found in sediments dated to 1.7 mya. The fossils at Dmanisi suggest that bands of Homo erectus began migrating out of Africa ata time very close its origin. Interestingly, though, the postcranial remains from Dmanisiare more primitive (more similar to earlier species; e.g., the hindlimb was relatively longer)than those found at many other sites.

The ability of Homo erectus to colonize land outside of Africa was also largely dependenton the new technology this species invented to deal with its surroundings. Homo erectuswas the rst species to actively control re; the rst good evidence for controlled re isfrom a Homo erectus site in Israel and is dated to roughly 780 ka. Homo erectus alsoinvented new technology for making stone tools. The types of tools used by this species arecalled the Acheulean industry. The Acheulean industry consists largely of handaxes (large,teardrop-shaped artifacts) and cleavers (large artifacts with chips removed on either side ofone end to create a sharp edge), but other tool types are also included. Handaxes areparticularly emblematic of the Acheulean industry. These artifacts are bifacially worked(chips removed from both sides of the original rock), creating sharp edges on most surfaces.Handaxes have been traditionally considered to be tools, but a growing minority ofscientists now argues that it was the akes of stones that were removed from the originalrock that were the tools that were ultimately utilized for hunting, butchery, and othertasks. Handaxes are found much less abundantly at sites in eastern Asia. This fact may bedue to underrepresentation




of Homo erectus site in the region (due, in turn, to lack of scienti c e orts in the regionand/or a real dearth of sites) or to the fact that other materials (e.g., bamboo) that do notpreserve in the archaeological record replaced handaxes. It is also possible that Homoerectus lost the tradition of making handaxes as it migrated from Africa to eastern Asia. No consensus has been reached on this subject.

The evolutionary relationships between Homo erectus and other hominin species are notfully resolved. Many scholars believe that Homo erectus evolved from Homo habilis,probably in East Africa. Recent nds in Kenya, however, have increased the temporalrange of Homo habilis, suggesting that the two species overlapped greatly in time andcausing some scientists to question the direct linkage between Homo habilis and Homoerectus. It is generally agreed, however, that Homo heidelbergensis evolved from Homoerectus in Africa and spread across the Old World replacing later populations of Homoerectus, in much the same way that Homo sapiens replaced Homo heidelbergensis andHomo neanderthalensis three-quarters of a million years later (see essays on Homo sapiensand Homo neanderthalensis).



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https://australianmuseum.net.au/image/Turkana-Boy-Homo-ergaster-skull/

(04) Homo ergaster - Australian Museum

Homo ergaster was the first of our ancestors to look more like modern humans.

‘Turkana Boy’ Homo ergaster skull Photographer: Stuart Humphreys © Australian Museum

These people were generally tall and slender and may also have been relatively hairless. Noteveryone accepts this species name, some still prefer to use the term African Homo erectus.

Background to discoveryAge

The core group within this species lived between 1.5 and 1.9 million years ago althoughsome classi cations include additional individuals that extends their range to betweenabout 700,000 and 2 million years ago.

Homo ergaster - Australian Museum

https://australianmuseum.net.au/homo-ergaster


Important fossil discoveries

Homo ergaster was rst proposed as a new species in 1975 after scientists re-examined afossil jaw previously identified as Homo habilis. Colin Groves and Vratislav Mazák noticedsome unique features about this jaw that made it di erent to our other human ancestors.These same features were later recognised in a group of fossils that had initially beenthought to be early forms of Homo erectus from Africa. All these fossils have now beenreclassi ed as Homo ergaster. New fossil discoveries have since been made and this speciesis now represented by fossils from males and females as well as adults and juveniles.

Important specimens

‘Turkana Boy’ KNM-WT 15000 – skeleton discovered in 1984 by Kamoya Kimeuin Nariokotome, West Turkana, Kenya. The Turkana Boy or ‘Nariokotome Boy’ ashe is sometimes called, lived about 1.5 million years ago. He was about 8 to 10 yearsof age when he died but was already 1.6 metres tall and may have reached 1.85 metresas an adult. Almost 90% of his skeleton was recovered and has provided valuableinformation on this species’ body size, proportions and development. The TurkanaBoy had a tall, slender body adapted for striding out across the extensive savannahplains. He also had a more human-like face with a nose that projected outwards and alarger braincase. SK 847 – a partial skull discovered in 1969 in Swartkrans, South Africa by RonaldClark. This skull was found in a cave with many fossils from another species,Paranthropus robustus. Stone tools and burned bones were also found at this site.The tool maker was probably Homo ergaster. Fire may have been used here about 1.5million years ago by Homo ergaster, although the burned bones may have resultedfrom a natural fire rather than from a controlled man-made fire.




KNM-ER 3733 – skull discovered in 1975 by Bernard Ngeneo and Richard Leakeyin Koobi Fora, East Turkana, Kenya. This is the skull of an adult female. Females hadless robust features compared with males such as ‘Turkana Boy’. KNM-ER 992 – a lower jaw discovered in 1971 by Bernard Ngeneo in Koobi Fora,East Turkana, Kenya. This lower jaw is the ‘type specimen’ or o cial representativeof this species. It was rst classi ed as Homo habilis, but was reclassi ed as Homoergaster in 1975 because it showed advanced features such as a lightly built jaw andrelatively small premolar and molar teeth. KNM-ER 42700 - A 1.5-million-year-old skull of a young adult discovered in Ileretin Kenya in 2000 (described in 2007). The skull has a very small brain of about691cc, the smallest for any Homo ergaster. This indicates that this species came in avariety of sizes, with males being much larger than females, which was unexpected forthis species. It also shows features that had previously only been found in AsianHomo erectus, such as the ridge on the frontal and parietal skull bones. This mix oftraits blurs the distinction between Asian Homo erectus and African Homo ergasterand has caused some experts to rethink whether these should be separate species.

BSN49/P27 – a female pelvis from Gona, Afar in Ethiopia, dated to 1.8 million yearsold. The size of this pelvis suggest the female was quite short at only about 130cm inheight, much smaller than has been estimated for females prior to this discovery. Thesize and shape also indicate the female could have given birth to a young with a brain30-50% the size of an adult’s. This suggests that the growth rate of the brain in thewomb was similar to that of a modern human but slowed down in the rst few yearsof life to a rate intermediate between modern humans and living chimpanzees.




Various fossils found in Eurasia at Dmanisi in the Republic of Georgia may belong toHomo ergaster. These Dmanisi fossils are signi cant because they currently representthe earliest evidence for the emergence of early humans from Africa into Eurasia 1.75million years ago. Key specimens include: Skull D2700 (discovered in 2001) with abrain size of 600 cc; Skull D2280 (discovered in 1999) with a brain szie of 780 cc andfeatures similar to Homo ergaster specimens KNM-WT 15000 and KNM-ER 3733;and Skull D2282 (discovered in 1999) with a brain size of about 650 cc and featuressimilar to KNM-WT 15000 and KNM-ER 3733. Fossil footprints from Ileret, Kenya, dated to 1.5 million years ago. These are theoldest known evidence of an essentially modern human-like foot anatomy and di erfrom the Laetoli footprints left by australopithecines 3.6 million years ago. The sizeand shape suggest that they were made by Homo ergaster, which also makes them theoldest surviving footprints made by a human species.

What the name means

Homo, is a Latin word meaning ‘human’ or ‘man’. It is the same genus or group name asthe one given to modern humans, which indicates the close relationship between thisspecies and our own.

The word ergaster is based on a Greek word meaning ‘work’, so the name Homo ergastermeans ‘workman’. This name was used because large stone tools were found near some ofits fossils.

Distribution

Fossils of this species have been found in Africa and Eurasia. Important sites includeregions around Lake Turkana and Lake Victoria, Koobi Fora, Nariokotome, Olorgesailie,Swartkrans and Dmanisi, Georgia.




Relationships with other speciesSome people do not recognise Homo ergaster as a species and instead classify these fossils asHomo erectus. Those who do accept Homo ergaster consider this species to be thecommon ancestor of two groups of humans that took di erent evolutionary paths. One ofthese groups was Homo erectus, the other group ultimately became our own speciesHomo sapiens.

Some fossils including the ‘type specimen’ (a jaw known as KNM-ER 992) were formerlyclassified as Homo habilis.

Finds from Dmanisi in Georgia are currently attributed by most scientists to this species,although new nds led to the suggestion in 2002 that these belong in a new species, Homogeorgicus. However, this is not widely accepted.

More recently, skull KNM-ER 42700, dating to 1.5 million years old and discovered inIleret in Kenya in 2000 (but described in 2007), blurs the distinction between AsianHomo erectus and African Homo ergaster. It shows features that had previously only beenfound in Asian Homo erectus specimens, such as the ridge on the frontal and parietal skullbones. This mix of traits caused some experts to rethink the whether these should beseparate species.

Key physical featuresThis species’ tall, long-legged body, with a atter face, a projecting nose and a somewhatexpanded brain was well along the evolutionary path leading to modern humans but it stillpossessed a number of intermediate features.




Body size and shape

the body is usually considered to be tall and slender with long legs which may havebeen an adaptation to maximise cooling of the body in a hot, dry environment.However, a pelvis found in 2000 suggests that females at least were broad-hipped andshort. females grew to about 160 centimetres in height whereas males reached about 180centimetres in height. the body may have been relatively hairless as a way of improving body cooling bysweating. ribcage was like that of modern humans in being barrel-shaped rather than cone-shaped as in earlier species. Along with changes to the shoulders, chest and waist, thisnew body shape improved the body’s balance and made it possible to run.

Brain

average brain size was approximately 860 cubic centimetres and made up about 1.6% oftheir body weight

Skull

had developed a more human-like shape including a higher, more domed cranium orbraincase. Unlike modern humans, the cranium had a moderate post-orbitalconstriction (indents behind the eye sockets). This feature is linked to brain size. Asour ancestors’ brains expanded, their skulls became fuller and more rounded withincreasingly smaller post-orbital constrictions. face projected outward but to a smaller degree than in earlier ancestors distinct double-arched brow ridge lay above the eyes and a relatively distinct groovewas located between the brow ridge and forehead

nose was human-like for the rst time. It now projected outward whereas earlierspecies had flat noses




Jaws and teeth

jaw was shorter and more lightly built than those of earlier species, resulting in aflatter, shorter face like earlier species, the front of the lower jaw sloped backward and did not form apointed chin like that of modern humans arrangement of the teeth within the jaws was intermediate between that of apes andmodern humans in that the side rows of teeth were much further apart at the back ofthe jaw than at the front canine teeth were modern in form, being short and blunt like those of modernhumans premolar and molar teeth were smaller and more human-like than those of earlierspecies.

Backbone and pelvis

pelvis was shaped like that of a modern human and was relatively narrow comparedwith species such as Australopithecus afarensis. This probably allowed more e cientmovement on two legs. a female pelvis specimen indicates that at least some females had quite broad-hippedbodies rather than the tall narrow body suggested by the Turkana Boy skeleton. Thispelvis shares some features with A.afarensis. body was vertically aligned above the pelvis.

vertebrae from the neck region of the backbone show that the spinal cord was thinnerthan in modern humans. This may indicate that this species had limited speechabilities due to the lack of nerves needed for the complex control of breathing whilespeaking.




Limbs

unlike earlier species, the legs were much longer than the arms, so the limbproportions were similar to those of modern humans tree climbing adaptations of earlier species had been lost and had given way to a long-legged striding walk that was an e cient way to move about and made it easier totravel longer distances an ability to run on two legs is suggested by a variety of limb features as well aschanges to the shoulders, chest and waist that enabled the body to stay balancedduring prolonged running

LifestyleCulture and technology

The technology of Homo ergaster became more advanced with the production of newkinds of stone tools. Other aspects of their behaviour also showed some signi cant changes,including the possible use of fire and increased levels of physical activity.

Tools

Large stone tools including hand axes, cleavers and picks (classi ed as Mode 2 technology)were manufactured. To make these tools, large stone akes were produced and these werethen shaped on two sides to produce sharp edges. This improved technology created moredurable tools that maintained their sharpness longer than earlier types of tools.Microscopic examination has shown their tools were mainly used on meat, bone, animalhides and wood.

Mode 2 technology includes straight-edged cleavers, pointed picks and hand axes. Thesetools are often called Acheulean stone tools after St Acheul in France where similar toolswere rst discovered during the 1800s. These tools were suitable for heavy duty workincluding processing bones for marrow, butchering large mammals and woodworking.This new technology was developed by Homo ergaster in Africa and was an improvementon the very simple stone choppers (Mode 1 technology) that earlier ancestors such asHomo habilis




had been using for about one million years. Later, Homo heidelbergensis continued touse this technology in Africa and they also took this technology with them when theyspread into Eurasia. One of the richest Acheulean stone tool sites in Africa is Olorgesailie,Kenya. Dating shows these tools were made over 700,000 years ago and they may even beup to 900,000 years old.

Fire

Fire may have been used as long as 1.5 million years ago for cooking and warmth butwhether this was a controlled use of re is not certain. Charcoal, burnt earth, and charredbones found associated with Homo ergaster fossils may have resulted from naturallyoccurring fires rather than from intentionally lit and controlled fires.

Recent reports (Current Anthropology vol 52, 4, August 2011) of discoveries inWonderwerk Cave, South Africa, suggest controlled use of re may have been occuring by1.7 million years ago. Strati ed deposits contain burnt stones, charred-calcined bones andtraces of ash that indicate repeated burning events. The discoverers conclude that the re-makers, most likely Homo ergaster, regularly gathered around the re to prepare and cookfood and also for social reasons.

Social behaviour

None of the Homo ergaster skeletons that have been found so far were deliberately buried.There is evidence however, that they did care for living members of their group who weresick or injured, but they did not seem to be concerned with their welfare after death.

It is probable that these people lived in social groups based on family bonds. A comparisonwith groups of primates living today suggests that these humans were moving away from adominant-male social structure. Their developmental rates show that they took longer tomature to adulthood than modern apes, but not as long as modern humans. This featuresuggests that Homo ergaster had an extended childhood period in which to completedevelopment to maturity.




Environment and diet

About 1.8 million years ago, the climate over most of Africa became drier and moreseasonal with extensive savannahs. Homo ergaster was the rst human species to takeadvantage of these more arid and open environments.

This species’ narrower pelvis and rib cage suggests that they had a smaller gut than earlierspecies such as Australopithecus afarensis. The development of a smaller gut and a biggerbrain required more nourishing food and this suggests that they may have included moremeat in their diets.

In the dry savannah environment, plant tubers would probably have been an importantpart of the diet. These tough vegetables may have been processed using their improvedtechnology as their smaller molar teeth imply that they ate foods that required less chewing.

Fran Dorey , Exhibition Project Coordinator Beth Blaxland , Education Project Officer Last Updated: 25 September 2015


https://australianmuseum.net.au/staff/fran-dorey

https://australianmuseum.net.au/staff/beth-blaxland


https://media4.s-nbcnews.com/j/streams/2013/october/131017/8c9411404-131017-coslog-skulls1-930a.nbcnews-ux-2880-1000.jpg



(05) Did the human family tree just get simpler? Skull stirs up debate

17 October, 2013

An oddball skull from a site in the former Soviet republic of Georgia has sparked a debate over early human evolution.

Putting together the pieces of a 1.8 million-year-old skull from the former Soviet republicof Georgia has led researchers to a surprising conclusion: Specimens that supposedlyrepresent several early human species might be merely di erent-sized individuals from thesame species.

If the conclusion holds up, the skull discovery would require a major rewrite for the storyof early human evolution. Such species as Homo habilis and Homo rudolfensis, long a partof humanity's "bushy" family tree, could be folded into a wide-ranging species known asHomo erectus.

Did the human family tree just get simpler? Skull stirs up debate

https://www.nbcnews.com/science/did-human-family-tree-just-get-simpler-skull-stirs-debate-8C11413284


"It is really an extraordinary nd in many respects," Christoph Zollikofer of Zurich'sAnthropological Institute and Museum, one of the researchers behind the study publishedin this week's issue of the journal Science, told reporters during a teleconference.

The key to the claim is the assembly of a fossil called Skull 5. The specimen was discoveredin separate pieces at a sprawling excavation in Dmanisi, about 50 miles (80 kilometers)from Tbilisi, Georgia's capital. Over the past eight years, Skull 5's jaw and the craniumwere painstakingly matched up and compared with four other hominid skulls unearthed atthe site.

The researchers were struck by the fact that Skull 5's braincase was relatively small, whilethe face was relatively large. What's more, other skeletal fossils associated with Skull 5suggested that the individual's body proportions were much like a modern human's.

This graphic shows the five skulls found at the Dmanisi dig, numbered 1 through 5."Had the braincase and the face of Skull 5 been found as separate fossils at di erent sites inAfrica, they might have been attributed to di erent species," Zollikofer said in a newsrelease. He and his colleagues also noticed size variations among all ve of the Dmanisiskulls — which led them to wonder whether di erent species in the genus Homo werebeing defined too narrowly.

An analysis of the various early Homo skulls from Africa, dating from 2.4 million and 1.2million years ago, found that the size variations were no wider than the variations found inmodern humans. The size differences were also in the range for chimpanzees and bonobos,the modern species that are considered closest to humans on the evolutionary tree.


http://www.sciencemag.org/content/342/6156/326.abstract



"Since we see a similar pattern and variation in the African fossil record ... it is sensible toassume that there was a single Homo species at that time in Africa," Zollikofer said."And since the Dmanisi hominids are so similar to the African ones, we further assumethat they both represent the same species."

That claim will have to be debated over the months and years ahead. Science quoted otherexperts as saying Skull 5 and the other fossils from Dmanisi may represent yet another newspecies in the genus Homo, or perhaps Homo habilis. One paleontologist, Fred Spoor ofthe Max Planck Institute for Evolutionary Anthropology, told Science's Ann Gibbons thatSkull 5 may well represent Homo erectus. But he balked at the idea that all the early Homofossils from Africa should be classified as Homo erectus as well.

Researchers say theindividual represented bySkull 5 had a relatively smallbraincase but a long faceand body proportionssimilar to a modernhuman's, as shown in thisartist's conception.

The study's lead author,David Lordkipanidze of theGeorgian NationalMuseum, told reportersthat the Dmanisi site couldprovide further insights intothe migration of earlyhumans and how theyinteracted with their




environment. "It's a real snapshot in time, and maybe a time capsule which preserves thewhole ecosystem which existed 1.8 million years ago," he said.

"There is a big gap in the fossil record," Zollikofer told NBC News. "I would put aquestion mark there. Of course it would be nice to say this was the last common ancestorof Neanderthals and us, but we simply don't know."

Although the researchers' hypothesis would trim back the earlier branches of the humanfamily tree, it doesn't address what happened during later eras of human evolution. Theconventional wisdom is that the descendants of early Homo species di erentiated intoNeanderthals, Denisovans, so-called "hobbits" and modern Homo sapiens.

Update for 3:25 p.m. ET Oct. 17:Update for 3:25 p.m. ET Oct. 17: Arizona State University paleoanthropologistDonald Johanson, who discovered the famous 3.2 million-year-old Lucy fossil skeletonalmost four decades ago, said Lordkipanidze and his colleagues have produced "a beautifullittle paper" — but he doesn't buy the claim that all of the earliest human species should belumped together.

"I think it's probably premature to dump everything into Homo erectus," Johanson toldNBC News. "This is what you're going to find the most opposition to."

The study's lead author, David Lordkipanidze of the Georgian National Museum, toldreporters that the Dmanisi site could provide further insights into the migration of early Johanson said the entire collection of specimens of early Homo species from East Africashows "considerably more variation than you see in this sample [from Dmanisi], which isnot surprising, because you're looking at fossils from very different regions."

He said the Dmanisi skulls reminded him of Homo ergaster, an African species that'ssimilar to Homo erectus specimens found farther east. "It strengthens the view that manyof us have held, that [Homo] ergaster was the species that got out of Africa to give rise tothis Dmanisi population, and that ultimately evolved into Homo erectus in Java,"Johanson said.


http://www.nbcnews.com/science/tag/neanderthals

http://www.nbcnews.com/science/new-technique-clears-mysteries-extinct-denisovan-human-genome-972347

http://www.nbcnews.com/id/50434876/

http://www.nbcnews.com/id/44182081/ns/technology_and_science-science/t/bid-rename-homo-sapiens-called-unwise/

https://webapp4.asu.edu/directory/person/50790

http://en.wikipedia.org/wiki/Homo_ergaster



Skull 5's small braincase also raised interesting questions, because humans living in Africaduring the same time period had larger brains. "That may suggest that these populations inAfrica and in Georgia were under different selective pressures," Johanson said.

He expected that "there'll be the normal bickering" over how to classify the Dmanisi skulls.Do they represent an existing fossil species, a new species, a subspecies or a sub-subspecies?In any case, Johanson said the newly reported findings will make a signi cant contributionto the study of early human evolution.

"It's just marvelous to have a real sample from a single locality of the same geological age,and such a comprehensive sample," Johanson told NBC News. "It's unsurpassed for thegenus Homo of this antiquity."



(06) Dmanisi Human: Skull from Georgia Implies All Early Homo Specieswere One | Anthropology

18 October, 2013

An analysis of a complete 1.8-million-year-old hominid skull found at theAn analysis of a complete 1.8-million-year-old hominid skull found at thearchaeological site of Dmanisi in Georgia suggests the earliest archaeological site of Dmanisi in Georgia suggests the earliest HomoHomo species – species –Homo habilis, Homo rudolfensis Homo habilis, Homo rudolfensis and so forth – actually belonged to the sameand so forth – actually belonged to the samespecies.species.

Skull 5 from Dmanisi, Georgia. Image credit: Guram Bumbiashvili / Georgian National Museum.

The skull fossil, called Skull 5, is the world’s rst completely preserved adult hominid skullfrom the early Pleistocene.

Unlike other Homo fossils, Skull 5 combines a small braincase with a long face and largeteeth. It was discovered alongside the remains of four other early human ancestors, avariety of animal fossils and some stone tools – all of them associated with the samelocation and time period – which make the find truly unique.

The archaeological site of Dmanisi, located in the Kvemo Kartli region of Georgia about93 km southwest of the capital Tbilisi, has only been partially excavated so far, but it’salready providing the rst opportunity for anthropologists to compare and contrast thephysical

Dmanisi Human: Skull from Georgia Implies All Early Homo Species were One | Anthropology

http://www.sci-news.com/othersciences/anthropology/science-dmanisi-human-skull-georgia-01474.html

(06) Dmanisi Human: Skull from Georgia Implies AllEarly Homo Species were One | Anthropology

traits of multiple human ancestors that apparently coincided in the same time andgeological space.

Image credit: Elisabeth Daynes, via tabula.ge.“The di erences between these Dmanisi fossils are no more pronounced than thosebetween ve modern humans or ve chimpanzees,” said Dr David Lordkipanidze fromthe Georgian National Museum in Tbilisi, a lead author of a paper in the journal Scienceand co-author of a paper published in the Proceedings of the National Academy ofSciences.

Traditionally, researchers have used variation among Homo fossils to de ne di erentspecies. But in light of these new ndings, Dr Lordkipanidze and his colleagues suggestthat

early, diverse Homo fossils, with their origins in Africa, actually represent variation amongmembers of a single, evolving lineage – most appropriately, Homo erectus.

This is an artist’s reconstruction of female Homo from Dmanisi, Georgia.


http://www.sciencemag.org/content/342/6156/326

http://www.pnas.org/content/early/2013/10/02/1316052110



“Had the braincase and the face of Skull 5 been found as separate fossils at di erent sites inAfrica, they might have been attributed to di erent species,” said Dr Christoph Zollikoferfrom the Anthropological Institute and Museum in Zurich, Switzerland, a co-author ofthe Science paper.

Computer reconstruction of Skull 5 and other four Dmanisi skulls; background – Dmanisilandscape. Image credit: Marcia Ponce de León / Christoph Zollikofer / University of Zurich.

That’s because Skull 5 unites some key features, like the tiny braincase and large face,which had not been observed together in an early Homo fossil until now.

Given their diverse physical traits, the fossils associated with Skull 5 at Dmanisi can becompared to various Homo fossils, including those found in Africa, dating back to about2.4 million years ago, as well as others unearthed in Asia and Europe, which are datedbetween 1.8 and 1.2 million years ago.

“The Dmanisi nds look quite di erent from one another, so it’s tempting to publishthem as different species,” Dr Zollikofer said.




“Yet we know that these individuals came from the same location and the same geologicaltime, so they could, in principle, represent a single population of a single species.”

The fossils from Dmanisi represent ancient human ancestors from the early Pleistoceneepoch, soon after early Homo diverged from Australopithecus and dispersed from Africa.

The jaw associated with Skull 5 was found five years before the cranium was discovered butwhen the two pieces were put together, they formed the most massively built skull everfound at the Dmanisi site. For this reason, the team suggests that the individual to whomSkull 5 belonged was male.

The braincase of Skull 5 is only about 33.3 cubic inches (546 cubic cm), however, whichsuggests that this early Homo had a small brain despite his modern human-like limbproportions and body size.

“Thanks to the relatively large Dmanisi sample, we see a lot of variation. But the amount ofvariation does not exceed that found in modern populations of our own species, nor inchimps and bonobos,” Dr Zollikofer said.

“Furthermore, since we see a similar pattern and range of variation in the African fossilrecord… it is sensible to assume that there was a single Homo species at that time in Africa.And since the Dmanisi hominids are so similar to the African ones, we further assume thatthey both represent the same species.”

Skull 5 seemingly indicates that, rather than several ecologically specialized Homo species,a single Homo species – able to cope with a variety of ecosystems – emerged from theAfrican continent. And accordingly, our classi cation system for these early humanancestors may never be the same.



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