Hunters and Farmers

c. 7 million–3000 BP

The Agricultural Revolution of the Neolithic (or New Stone Age) transformed the whole of human social experience. Only the Industrial Revolution has had a comparable impact.

Our story begins with a rapid survey of a vast span of time from about seven million years ago to about 5,000 years ago. During this period, as a product of biological, environmental, cultural, and social evolution, a succession of radical transformations took place. First, around 7–6 million years ago, in Chad or Kenya, we have the appearance of the first potential hominins, that is, creatures on our evolutionary tree after our split from the ancestors of the chimpanzees.

Second, around 3.3 million years ago, in Kenya, we have the first evidence of tool-making, representing a fundamental change in hominin behaviour. This and subsequent early technologies (such as the more famous Oldowan tools) are very basic. But then, around 1.9 million years ago, in East and South Africa, certain hominins evolved into creatures with larger brains, greater capacity for tool-making, and higher levels of social organisation and environmental adaptability. This creature had a fairly modern body-shape and is known as Homo ergaster ('Working Human'). This species was very similar to Homo erectus ('Upright Human'), a fossil type not really known in Africa, but widely distributed across Asia.

Third, after c. 350,000 years ago, we have the first evidence for ourselves: Homo sapiens ('Thinking Human'). These, our direct ancestors, seem to have originated in Morocco. The early fossils, however, display a mix of archaic and modern characteristics, and our species only became fully anatomically (and presumably cerebrally) modern by about 120,000 years ago.

Fourth, about 10,000 years ago, under the impact of climate change and food shortages, some communities made the transition from hunting and gathering to farming.

Fifth, about 6,000 years ago, new techniques of land reclamation and intensive farming allowed some communities in favoured locations to increase their output substantially by moving from hoe-based cultivation to plough-based agriculture.

The Hominin Transformations

We have evidence for creatures considered to be hominins reaching back to seven million years BP (before the present; the usual term when discussing hominin evolution). On the human tree roll-call the earliest is Sahelanthropus tchadensis, found in Chad (7–6 BP), whose status as a hominin is rather insecure, but it may have partially walked on two feet (bipedalism being one of the main characteristics of hominins). Then comes Orrorin tugensis from Kenya (6.2–5.6 BP), who may also hold the title of earliest bipedal hominin.

These two creatures (and there were probably many more: we just have not found them) were followed by other hominins such as Ardipithecus ramidus (4.5–4.3 BP) from Ethiopia and Kenyanthropus platyops from Kenya (3.5–3.3 BP).

But perhaps the best-known early hominin was the australopithecine, who emerged around 4.2 BP in East Africa. One of these, Australopithecus afarensis ('Southern Ape of Afar'), roamed throughout parts of East Africa (including Laetoli, where a small family left footsteps in the mud) around 3.7–3 million BP. We have found the fragmented remains of several hundred such creatures, and they reveal evidence for both a bipedal and a tree-based (arboreal) lifestyle. The best-known specimen of Australopithecus afarensis is the 40 per cent complete skeleton of 'Lucy' found in 1974 (though she may have been male).

Lucy stood just 1.1 m tall, weighed around 29 kg, and was probably about 20 years old when she died. With short legs, long arms, and a small brain case, Lucy would have looked rather like a modern chimpanzee. But there was a crucial difference: like all (certain) hominins, she was able to walk upright (though she could also climb and would have spent some of her time in trees). The shape of her pelvis and legs, and the knee joint of another member of the species found a short distance away, proved this beyond reasonable doubt.

Lucy was probably one of a small foraging group that moved around gathering fruit, nuts, seeds, eggs, and other foodstuffs. As climate change reduced the forests and created savannah, natural selection had favoured a species able to range over greater distances in search of food. But Lucy's bipedalism had revolutionary implications. It freed the hands and arms for tool-making and other forms of labour. This in turn encouraged natural selection in favour of larger brain capacity. A powerful dynamic of evolutionary change was set in motion: hand and brain, labour and intellect, skill and thought began an explosive interaction – one which culminated in modern humans.

We do not know whether Lucy made tools. None were found in association with her remains. But very early and very crude stone tools have recently been discovered dating to 3.3 million BP in Kenya – and may be associated with other forms of local australopithecines. And certainly, by 2.5 million BP, Homo habilis ('Handy Human') – Lucy's potential descendant – certainly did. Choppers made from crudely chipped pebbles represent the archaeological imprint of a new family of species defined by tool-making behaviour: the genus Homo ('Human'). Tools embody conceptual thought, forward planning, and manual dexterity. They reveal the use of intellect and skill to modify nature in order to exploit its resources more efficiently.

The genus Homo, like the australopithecines before them, evolved in Africa, and for about 1.5 million BP that is where they largely remained. After around 1.8 million BP, however, we start finding evidence for Homo erectus in the Far East (China, Java, Indonesia) and also in Georgia near the Black Sea (though some define this creature as Homo georgicus).

Homo erectus seems to have been very closely related to an African form, Homo ergaster, an...