EARLY AND LATER PREHISTORY
trace the very beginning of the human story in Africa, from evolutionary origins, through the long millennia of hunting and gathering to the development of farming and pastoralism. This very ancient period is usually referred to as ‘prehistory’ – a time before identifiable individuals or communities become apparent. The term ‘prehistoric’ is often used today to imply that something is primitive, backward or out of date. The implication is that nothing can usefully be learned from the prehistoric; that this was an unimportant, timeless period in which little of significance happened. But nothing could be further from the truth. The people of prehistory had to deal with major themes that have particular relevance to the world today – climate and environmental change, migration, egalitarianism versus sharp divisions of wealth, the political and economic organisation of society and the use and abuse of power. As such, they have much to teach us.
Compared with us today, all that these people lacked was our accumulated technological know-how and recorded experience. Things that might seem obvious to us today, such as the bow and arrow as a specialised weapon for hunting, had to be invented – thought of, thought out, experimented with and perfected – with no prior example, book or internet to consult. These people were intelligent pioneers of human thought and experience. They worked out a harmonious relationship with the wide range of environments in which they lived, and learned to adapt when climate and environmental conditions changed, to an extent which our modern, ‘sophisticated’ societies could learn from. They were pioneers of technology, from simple microliths for tools, to grinding stones for making flour and baked clay pottery for storing and cooking food.
They developed religious thought, relating it to the world around them, especially the animals, the rain and the sun, on whom they all depended. And they worked out various forms of societal organisation. These ranged from small-scale hunter-gatherer family groups to the larger, more complex societies that developed with the adoption of pastoralism and cultivation. The latter enabled the growth of division between rich and poor and with it the emergence of powerful leaders. Religious beliefs were adapted to these changed circumstances – leaders often using religion as a basis for their monopoly of power.
traces the origins of human evolution, considering the evidence of fossils, environment and DNA analysis. It follows the development of a hunter-gatherer lifestyle, and the spread and settlement of Africa’s main modern linguistic groupings, up to the dawn of the agricultural revolution. Chapter 2
discusses the emergence of crop cultivation and animal husbandry from about 10,000 years ago, and its spread and impact within
Africa. Politically, farming’s biggest impact was the ability to sustain an urban population, none more so than in the unique environment of the lower valley of the Nile. The chapter thus concludes with Ancient Egypt, a classic example of the transition from prehistory to recorded history. The most striking theme of this final section is the extremity of autocracy that political power can reach and the use and abuse of that power in Ancient Egypt.
Early prehistory of Africa
The most important thing to understand about the science of evolutionary theory is that it is constantly evolving in the light of new evidence and the reinterpretation of old evidence. But one thing that has stood the test of time is the conclusion that Africa was the continent in which early forms of humans and fully modern humans, with brains just like ours, first evolved. And it was from Africa that they finally spread to inhabit the rest of the world.
The material evidence for human evolution has been found in the form of ancient bones, fossils, stone tools and other artefacts. Fossils are formed when animal or plant remains are trapped in mud that is then squeezed under great geological pressure to form rock. All that remains of the organic matter within the rock is an exact imprint (a fossil) that is revealed if the rock is broken open, by further natural process or by human intervention. Scientific geological methods can be used to give an approximate age to the formation of rocks and hence to their fossils.
The potassium-argon dating technique measures the changing ratio between these two elements during radioactive decay in rocks that are over 1 million years old. It is particularly useful for the volcanic rocks of Ethiopia and the East African Rift. Radiocarbon dating measures the radioactive decay of carbon-14 atoms in dead organic matter, such as bones and charcoal, that is less than 40,000 years old. It cannot measure a precise age, but instead offers a probable age range and is most useful in providing a chronology rather than a particular date.
The increasing sophistication of the modern study of genetics has made DNA analysis an important tool for tracing relationships between ancient peoples and their movement both within and out of Africa.
Archaeologists have recently come to appreciate the importance of climate change as a potential influence on early human development and behaviour. The earth has gone through many changes in climate during the millions of years of its existence, and scientists are able to measure past climates by taking deep borings from the ice sheet, particularly in Greenland. From these and from borings into the ocean floor, it is possible to measure the climate of the distant past.
At times, the world’s climate has been a lot colder than at present, with the ice coverage of the poles being extended well into the temperate zones of Europe, Asia and North America. These ultra-cold periods, often lasting for thousands of years, are commonly known as ‘ice ages’. Africa lies beyond the range of the northern and southern ice sheets, but during the ice ages of the past, with much of the world’s fresh water – and thus potential rain – tied up in ice, Africa experienced these
periods as times of extreme dryness. Deserts expanded and the rainforest contracted, sometimes into isolated ‘islands’ of forest growth in the heart of the Congo Basin. Many animals could not cope with the changed environment and became extinct, and early humans too had to adapt or die.
There have been times, too, when the climate has been a lot warmer than at present. In those periods, the ice sheets melted, extra moisture was released into the air and Africa experienced much higher rainfall. Then the rainforest expanded, rivers flowed where today is only desert, and the Sahara itself was covered in savannah grassland.
The earliest hominins
In terms of evolution, modern human beings belong to the primate family of ‘hominins’. Hominin (formerly known as hominid) is a general biological name for human or humanlike creatures with enlarged brains and the ability to walk upright on two legs. For tens of thousands of years, modern human beings have been the only surviving hominins. But, in the early stages of human evolution, there were a number of different species. From the fossil evidence, it appears that many millions of years ago the earliest species of hominin evolved away from the other main family of primates, the great African forest apes: the gorilla and the chimpanzee.
There are significant gaps in the fossil evidence and so little is known about the earliest hominins. But it appears that sometime between about 10 million and 5 million years ago, perhaps during a glacial dry period when the tropical forest contracted, they moved into the more open savannah grasslands and woodlands of eastern and southern Africa. There they began to develop the techniques of standing and walking on two legs. In terms of survival and evolution this had a number of distinct advantages. In the open savannah, standing upright enabled them to see over the grassland and spot predators such as lions and leopards that hunted them for food. Those best able to stand upright survived longer, reproduced more and passed this advantage on to their descendants. A further highly important advantage of two-legged walking was that it left the hands free to carry food and use tools. Fingers no longer needed to be short and strong for hanging on to branches in the forest. The early hominins were able to evolve elongated fingers for performing intricate tasks and, eventually, for making their own tools.
The Australopithecines and early evolution of Homo (man)
The fossil record of the past 5 million years is continually being expanded with finds of early hominin fossils from eastern and southern Africa as well as the Sahara. The evidence up to 1.5 million years ago forms a complex story of the evolution and extinction of numerous related species of early hominin. Most of these belong to the genus known as Australopithecus (‘southern ape’). They were largely scavengers, some vegetarian, others meat-eaters, and they had a brain capacity less than a third that of modern humans. They were tool users rather than toolmakers: they did not shape their own tools, b...