World Prehistory: The Basics

Brian M. Fagan, Nadia Durrani

• Éditeur: Routledge
• Année: 2021
• ISBN:
  9781000466799
• Édition: 1
• Sujet: Scienze sociali
• Sous-sujet: Archeologia

World Prehistory: The Basics tells the compelling story of human prehistory, from our African origins to the spectacular pre-industrial civilizations and cities of the more recent past.

Written in a non-technical style by two archaeologists and experienced writers about the past, the story begins with human origins in Africa some 6 million years ago and the spread of our remote ancestors across the Old World. Then we return to Africa and describe the emergence of Homo sapiens (modern humans) over 300, 000 years ago, then, much later, their permanent settlement of Europe, Eurasia, Asia, and the Americas. From hunters and foragers, we turn to the origins of farming and animal domestication in different parts of the world after about 11, 000 years ago and show how these new economies changed human existence dramatically. Five chapters tell the stories of the great pre-industrial civilizations that emerged after 5000 years before present in the Old World and the Americas, their strengths, volatility, and weaknesses. These chapters describe powerful rulers and their ideologies, also the lives of non-elites. The narratives chronicle the rise and fall of civilizations, and the devastating effects of long droughts on many of them. The closing chapter poses a question: Why is world prehistory important in the modern world? What does it tell us about ourselves?

Providing a simple, but entertaining and stimulating, account of the prehistoric past from human origins to today from a global perspective, World Prehistory: The Basics is the ideal guide to the story of our early human past and its relevance to the modern world.

1

BEGINNINGS (C. 6 TO 2 MA)

DOI: 10.4324/9781003177326-1

About 3.7 million years ago, a volcano named Sadiman in Tanzania, East Africa, erupted with a cloud of fine ash. The cascading volcanic dust fell in a thin layer on the surrounding landscape at Laetoli. Then light rain fell, creating a soft, cement-like pathway in a seasonal river that led to nearby waterholes. Dozens of now-extinct animals walked along the riverbed soon afterward—elephants, saber-toothed tigers, and antelope. Another subsequent eruption sealed the hardened surface with its footprints, which included those of two human ancestors. Trailing behind them, often stepping directly into the adult footprints, are those of a child.

We have but an indirect sketch of the walkers. The imprints came from individuals between 1.4 and 1.49 meters tall. They walked with a rolling, slow-moving gait, their hips swiveling with each step, very different from the free-standing gait of modern humans. Their footprints display well developed arches, with heel and toe prints that could only have been made by someone walking on two feet—very different from those of upright chimpanzees.

The Laetoli footprints provide a glimpse of early hominins and, their discovery in the 1970s, led to the bombshell realization that bipedalism (walking on two feet) preceded growth in brain size, and not the other way round. Researchers realized that upright walking meant our hands were now free. This meant we could make things—and creativity is a key attribute of our human family.

Figure 1.1 A replica of two australopithecines leaving footprints in lava, 3.7 Ma.

Martin Shields/Alamy Stock Photo

HOMINIDAE AND HOMININI

First, some genealogy. We humans are members of the order Primates, which includes two suborders, one of which includes the Anthropoids, which incorporates apes, people, and monkeys. Further up the genealogical pyramid, we belong to the superfamily Hominoidea, which also includes gibbons, gorillas, chimpanzees, and the bonobo. Within the hominoid superfamily, there’s a division between Hominidae, which includes African and Asian apes, as well as us. We belong to the Hominini (or hominin) tribe, which includes modern humans, earlier human subspecies, and their direct ancestors.

To date, researchers have identified over 20 hominin species, but only some of them are our ancestors, many becoming extinct without giving rise to new species. At any given time over much of the past six million years, several hominin species co-existed. (A species is typically defined as a group of organisms that can provide fertile offspring.) It was only after around 30,000 years ago, that the other human species became extinct and only we—Homo sapiens—remained. But, given the scanty archaeological record for the early period, how do we know when hominins separated from non-human primates?

IN THE BEGINNING

By 14 Ma, Africa’s climate was much drier than in earlier times. Hard-fruit and grass-eating hominoids flourished throughout East Africa between 8 and 5 Ma. They spent much time on the ground but walked on four feet. Unfortunately, we know almost nothing about these hominoids. They lived at a time of major environmental changes, including cooler temperatures and more open, as opposed to wooded, terrain. Today’s humans are the descendants of these generalized common hominoid ancestors. As forests retreated and tropical Africa’s climate became drier, they adapted to much more open savanna environments.

This was when early hominins became bipedal, perhaps because they spent more time feeding off foods on the ground. Bipedalism meant that walking assumed great importance for foraging over wider areas.

In adapting to drier environments, early hominin populations with their bipedalism could cover longer distances and had improved endurance. Apes, which were adapted to forested environments, stayed in the trees. In contrast, bipedal hominins, who potentially evolved around 6 Ma, expanded the range of territory where they obtained food. They broadened their diets, now including more meat.

The long-term solutions to living in the savanna meant exploiting patchy and widely distributed foods, while depending on reliable, and often hard-to-find, water supplies. The hominins were constantly on the move, with meat now playing a more important role during seasons when plant foods were scarce.

Most experts believe that East Africa was the main center of early human evolution. It is here that the greatest number of early hominins have come to light. But future fossil discoveries may complicate this scenario. The now-desert environments of Ethiopia and northern Kenya were open savanna grassland and woodland that teemed with herds of antelope and other mammals. These were prey for lions, leopards, and other predators, and also for our early hominin ancestors. We know almost nothing of these hominins, except the little known, probably bipedal, Orrronin tugenensis, who lived about 6.5 to 5.6 Ma. There is also Sahelanthropus tchadensis, of Central African origin. The latter may date to 7–6 Ma, which would place it at around the time of the likely divergence of the hominin lineage with that of the chimpanzee.

The date of this split depends less on the spartan fossil evidence, and more on genetic analysis of modern humans and modern chimps. By recording the amount by which the genes of the two species have diverged, geneticists theorize the time of our split. This method of timing, known as the “molecular clock”, is based on a number of assumptions, which are constantly refined. And while there is disagreement over the precise date of our split, most geneticists currently put it somewhere between 8 and 6 Ma. As to the hominins that lived at the dawn of our story, certainly the two species referred to above were potentially bipedal (a defining characteristic of the hominin) yet they were also tree climbers.

ARDIPITHECUS RAMIDUS (4.5 MA)

As the centuries turned into millennia, other hominin species undoubtedly came and went, such as Ardipithecus kadabba of Ethiopia (5.8–5.2 Ma) (Figure 1.2). But around 4.5 Ma, a new player appeared on the evolutionary stage with the appearance of Ardipithecus ramidus, a small creature with a brain that was about 20 percent the size of that of a modern human. Ardipithecus is the best known of all the early hominins and comes from excavations at Aramis and Goma in Ethiopia. It had a skull closer to that of apes, and a prognathous (jutting out) face. These hominins were bipedal, but apparently lived in more wooded terrain than many of their successors. Various australopithecines followed, such as Australopithecus anamensis (4.2–3.9 Ma) who, like Ardi, could probably walk upright and climb trees, possessing (once again) a combination of characteristics found both in modern apes and present-day humans.

Figure 1.2 Map showing early sites in Africa.

Ardipithecus ramidus was not the only hominin in East Africa at the time. Most likely, they were the base grade from which later hominins evolved. But the exact relationship between Ardipithecus and later human ancestors is still a mystery.

AUSTRALOPITHECUS AFARENSIS: THE “SOUTHERN APE FROM AFAR” (C. 3.9 TO 2.9 MA)

After hundreds of thousands of years—and we’re talking about long timescales here—one of the best known australopithecines emerged; Australopithecus afarensis. It may be the ancestor of the genus Homo, to which modern humans—us—belong.

Australopithecus afarensis has already appeared in this story, thanks to its footprints at Laetoli in Tanzania. These hominins are best known from the Hadar region of Ethiopia, famous for Maurice Taieb and Donald Johanson’s discovery of a 3.18-million-year-old incomplete skeleton that they named Lucy. (They were playing the Beatles’ song, Lucy in the Sky with Diamonds when they celebrated their discovery.) She was only 1.0 to 1.2 meters tall and between 19 and 21 years old.

Subsequent finds have filled in the picture. There was a marked difference between males and much smaller females. But all were powerful, heavily muscled, and fully bipedal. A 3.2 Ma foot found near Lucy’s find-spot had arches, showing that Ardipithecus was a nimble walker. But despite this walking ability, their robust, curved arms and fingers are those of habitual tree climbers. Their brain capacity was just larger than the maximum brain size of modern chimpanzees.

At first, Australopithecus afarensis appeared to be confined to East Africa, but they probably flourished over a much wider area, into southern Africa. Whether or not these discoveries represent more than one species of australopithecine remains unknown, but Australopithecus afarensis may have been the most widespread.

Around 3 Ma, the record includes a species identified by the famed anatomist Raymond Dart in the 1920s. He recognized a small, graceful australopithecine from Taung in South Africa, which he named Australopithecus africanus (3.3–2.1 Ma). This was a nimble hominin, who could walk upright—despite its small brain size (samples range from 428–625 cubic cm). Dart’s close ally, Robert Broom, then discovered another species, Australopithecus robustus (since renamed Paranthropus robustus), a heavy-set hominin that flourished between about 2 and 1 Ma. They had similar sized brains (530 cubic cm) and massive back teeth, which were ideal for chewing coarse, fibrous plant foods.

Due to these two species, Raymond Dart emphasized a robust and gracile subdivision among the early humans, which is still convenient. But, inevitably, later discoveries have revealed a greater diversity of australopithecines and paranthropines, especially between 3.3 and 2 Ma. This long period of time witnessed major changes in the skull and face, and perhaps more modern behavioral changes too, as our ancestors began routinely walking upright. This meant their hands were now freed up (which in turn allowed them to make things, arguably with more ease than a four-footed creature). Indeed, a site in Kenya has yielded the oldest known human-made stone tools in the world—at 3.3 Ma, which were clearly the work of one of these early hominin forms.

ENTER HOMO HABILIS (C. 2.5 MA)

Sometime around 2.5 Ma, we find evidence for Homo habilis, the first member of the genus Homo—to which we modern humans belong. They had larger brains, smaller jaws and teeth, also longer legs, shorter arms, and nimble hands. Their larger, opposable thumbs, like ours, allowed them to pinch and manipulate objects in different directions. Body size tended to increase. The size differences between males and females (sexual dimorphism) became less marked. These changes roughly coincided with the first appearance of stone tools.

Louis and Mary Leakey were the first to identify this earliest Homo at Olduvai Gorge (now often called Oldupai) in Tanzania. They named their find Homo habilis, “handy person”, assuming that this was the first toolmaking human. Subsequently, fossil remains of Homo habilis have come from Kenya, Ethiopia, and South Africa, dating to between 2.4 and 1.6 Ma.

The term Homo habilis almost certainly encompasses several early human species, sometimes referred to generically as early Homo. If you had encountered Homo habilis about 2 million years ago, you would have seen little to distinguish the new hominin from Australopithecus. Both were of similar height and weight, about 1.3 meters tall and weighing about 40 kilograms. They were both bipedal, but habilis looked less ape-like around the face and skull. The head was higher and rounder, the brain capacity as high as 700 cc, the face less protruding, and the jaw smaller. (Adult chimpanzees have brain capacities around 384 cc.) Micro...