HOMO ERGASTER: THE WORKING MAN

Homo Ergaster

Homo Ergaster, working man, is an extinct hominid species or subspecies, according to some authorities, which lived throughout eastern and southern Africa between 1.9 to 1.4 million years ago with the advent of the lower Pleistocene and the cooling of the global climate.

Homo Ergaster is sometimes categorized as a subspecies of Homo Erectus. It is currently somewhat controversial whether Homo Ergaster or the later, Asian H. erectus was the direct ancestor of modern humans. The genetic variability among modern Homo Sapiens is greatest in Africa, which suggests strongly that this is the area where the species arose and has had most time to accumulate variation. Homo Ergaster may be distinguished from Homo Erectus by its thinner skull bones and lack of an obvious sulcus.

Derived features include reduced sexual dimorphism; a smaller, more orthognathic face; a smaller dental arcade; and a larger (700 and 850cc) cranial capacity.

More information: Brad Shaw Foundation

It is estimated that Homo Ergaster stood at 1.9m (6ft3) tall with relatively less sexual dimorphism in comparison to earlier hominins.

Remains have been found in Tanzania, Ethiopia, Kenya, and South Africa. The most complete Homo Ergaster skeleton ever discovered was made at Lake Turkana, Kenya in 1984.

Paleoanthropologists Richard Leakey, Kamoya Kimeu and Tim White dubbed the 1.6 million year old specimen as KNM-WT 15000, nicknamed Turkana Boy. The type specimen of Homo Ergaster is KNM ER 992; the species was named by Groves and Mazak in 1975.

The species name originates from the Greek Ergaster meaning Workman. This name was chosen due to the discovery of various tools such as hand-axes and cleavers near the skeletal remains of Homo Ergaster. This is one of the reasons that it is sometimes set apart distinctly from other human ancestors. Its use of advanced, rather than simple, tools was unique to this species.

Homo Ergaster tool use belongs to the Acheulean industry and first began using these tools 1.6 million years ago. Charred animal bones in fossil deposits and traces of camps suggest that the species made creative use of fire.

More information: EFossils

To investigate the history of man's development, 
the most important finds are, of course, hominid fossils.

Richard Leakey

LUCY: AUSTRALOPITHECUS AFARENSIS

Lucy

Australopithecus Afarensis is one of the best known of our ancestors due to a number of major discoveries including a set of fossil footprints and a fairly complete fossil skeleton of a female nicknamed 'Lucy'.This species lived between 3.9 and 2.8 million years ago. Australopithecus means ‘southern ape’ and was originally developed for a species found in South Africa. This is the genus or group name and several closely related species now share this name.

The word afarensis is based on the location where some of the first fossils for this species were discovered – the Afar Depression in Ethiopia, Africa.

During the 1970s, two fossil hunting teams began uncovering evidence of ancient human ancestors in east Africa. One team, co-led by Donald Johanson, was working at Hadar in Ethiopia. The other team led by Mary Leakey, was over 1,500 kilometres away at Laetoli in Tanzania. Fossils discovered at the two sites were found to have very similar features and ages but they did not match the fossils of any species known at that time. A new species name, Australopithecus afarensis, was therefore created for them in 1978.

More information: Lucy's Story by Institute of Human Origins

This species is now represented by several hundred fossils from east Africa like ‘Lucy’AL 288-1, Knee AL 129 1a + 1b, LH 4, The ‘First Family’, ‘Selam’ or ‘Lucy’s baby and ‘Lucy's big brother'.

Australopithecus afarensis is usually considered to be a direct ancestor of humans. It is also considered to be a direct ancestor of later species of Australopithecus and all species in the Paranthropus genus.

More information: Smithsonian Institution

The names Praeanthropus africanus and Praeanthropus afarensis have been suggested as alternatives by researchers who believe this species does not belong in the genus Australopithecus.

Fossils show this species was bipedal (able to walk on two legs) but still retained many ape-like features including adaptations for tree climbing, a small brain, and a long jaw.

This species probably used simple tools that may have included sticks and other non-durable plant materials found in the immediate surroundings. 

Stones may also have been used as tools, but there is no evidence that stones were shaped or modified in any way. 


It seems likely that they lived in small social groups containing a mixture of males and females, children and adults. Females were much smaller than males.

This species occupied a range of environments. Some populations lived in savannah or sparse woodland; others lived in denser forests beside lakes. Analysis of their teeth, skull and body shape indicates a diet that consisted mainly of plants. However, fossil animal bones with cut marks found in Dikika in 2010 have been attributed to this species, suggesting they may have included significant amounts of meat in their diets.

Microscopic analysis of their tooth enamel shows that they mostly ate fruits and leaves rather than seeds and other hard plant material. Their cone-shaped rib cage indicates they had large bellies adapted to a relatively low quality and high bulk diet. The position of the sagittal crest toward the back of the skull indicates that the front teeth processed most of the food.

More information: IPHES

If you were to go to the National Museum in Addis Ababa, you would walk into a huge room filled with literally tens of tons of fossils, and most of them would be elephants and rhinos and hippopotamus and monkeys and giraffes and antelopes and so on. Hominids are very rare in the landscape, and it's very rare to find them.

 Donald Johnson