I really enjoyed this book, Before the Dawn. The latest in genetic research is added to what is known from the archaeological record about humans from prehistory.
To help me remember the milestone moments in human prehistory, I’ve listed the key points from the book below:
* Global cooling (with accompanying drought because water was tied up in glaciers) about 5 million years ago put pressure on the ape population. Bipedalism is probably the first major evolutionary change, as the open grasslands represented an environmental niche to exploit. At that time the sexes were of different size, with probably their own separate hierarchies. Male-female ongoing pair-bonding did not appear until much later.
* Another cool period about 2-3 million years ago put more pressure on the australopithecines. Homo habilis appeared, and it was a meat eater. A smaller gut and smaller teeth for these meat-eaters meant more metabolic energy for a larger brain. The first stone tools appeared about 2.5 million years ago.
* 1.7 million years ago, Homo ergaster appears. Ergaster’s arms were human length, not ape length. A barrel-shaped chest over a smaller belly meant Ergaster was a meat-eater, and maybe a tuber-eater. It’s possible Ergaster cooked the starchy tubers, releasing more nutrients to accompany meat-eating. Ergaster males were much closer in size to Ergaster females– this might suggest the beginning of a more equal pair-bond family structure. The birth canal in Ergaster females was smaller than in Habilis, and so the larger brain of infants had to develop outside the womb. Fathers may have needed to stay around and protect the females and infants. More advanced stone tools appeared with Ergaster.
* Ergaster possessed an external nose, an adaptation to hot, dry climates (a nose conserves water by cooling and condensing moist air as it leaves the lungs). Ergaster probably lost its hair to allow for sweating– another method of cooling. Skin covered with hair is white, so there needed to be an evolution in the melanocortin receptor (a protein that helps determine skin colour). Ergaster and subsequent descendants probably had black skin, until humans migrated northward after the ice age, where lighter skin boosted Vitamin D production from the limited sunlight.
* Homo erectus was the first to reach Asia, about 1 million years ago. About 500,000 years ago, Homo heidelbergensis reached Europe. Under the glacial conditions of 400,000 to 300,000 years ago, the new migrants in Europe evolved into Homo neanderthalensis.
* Human head hair, unlike an ape’s, doesn’t stop growing. Modern (or near-modern) humans, probably around 200,000 years ago, developed uncontrolled hair growth after a mutation in the keratin genes, which regulate hair growth.
* Anatomically modern humans appeared about 200,000 years ago, but there was no apparent change in behaviour (the tool set remained the same).
* The FOXP2 gene is intimately involved with human language, and it mutated within the last 200,000 years. The mutation may have been so beneficial that is quickly swept through the population over time.
* During a warm period, about 125,000 to 90,000 years ago, people began to escape Africa, reaching what is now Israel. But a cold period about 80,000 to 70,000 years ago brought Neanderthal down from the north and they likely destroyed the emigrants.
* The first clothes. Head and body lice have different genetic histories, and body lice evolved from head lice to take advantage of the new "environment" of human clothing around 72,000 years ago. At this time language was being perfected. Anatomically modern humans appeared about 100,000 years ago, but modern behaviour appeared about 50,000 years ago, with some evolutionary changes occurring right after the last ice age.
* A group of the first modern humans (perhaps only about 150 individuals split off from the main group) left Africa by crossing the Red Sea (at a spot called the Gate of Grief) to Arabia (sea level was lower because of water tied up in glaciers) about 50,000 years ago. The original ancestral population of modern humans may have numbered only 5000 people and they lived in northeastern Africa. Once humans reached India, the populations diverged, some going to Australia over the land bridges (because of low sea level again) and short distances over water by boat, and others turning northwest to "evict" the Neanderthal from Europe. Homo erectus probably had contact with modern humans, and Homo floresiensis (probably descended from Homo erectus) survived on an island in Indonesia for a long time.
* In Europe, about 45,000 years ago, new stone tools appeared, brought by humans, who began to displace Neanderthal. This culture is called Upper Paleolithic. It is believed by some that the behavioural change was brought about by the development of language which preceded the departure of modern humans from Africa about 50,000 years ago.
* Upper Paleolithic (45,000 to 10,000 years ago). Neolithic age followed– new tools and agriculture appeared. During the Upper Paleolithic, Europe and Asia were populated by modern humans, and Neanderthal disappeared about 30,000 years ago. About 20,000 years ago there was a return of the ice age called the Last Glacial Maximum.
* In Europe in the Upper Paleolithic, there were several cultural eras: first, the Aurignacian (45,000 to 28,000 years ago). The Aurignacians drove the Neanderthal to extinction. They painted the Chauvet cave in the Ardèche Valley of France. That cave was occupied from 32,000 to 30,000 years ago and then from 27,000 to 25,000 years ago.
* Next was the Gravettian culture (28,000 to 21,000 years ago). The produced the Venus figurines, with their dwarf heads, ample breasts, and steatopygous buttocks (these large buttocks are believed to be attributes of the earliest humans, and are reminiscent of those found on isolated populations that contain the genes most similar to the earliest humans– the San of Africa and the Andaman of Indonesia). The worsening cold of the Last Glacial Maximum drove the population south.
* Next was the Solutrean culture (21,000 to 16,500 years ago). These people lived close together. Some tools appear to be ceremonial in purpose, suggesting that more elaborate social rituals took place. The Last Glacial Maximum lasted for 5000 years, eventually yielding back the rich plains of Eurasia to humans.
* The people spreading back out into France and Germany created the Magdalenian culture (18,000 to 11,000 years ago). The cave art of Lascaux was Magdalenian, dated to 17,000 years ago. Other cave art was found in Niaux and Altamira. The source of repopulation was from the Basque region, which is also the likely source of the unusual Basque language.
* The people of Siberia (genetic brothers to the Aurignacians), during the Last Glacial Maximum, were the first to domesticate the dog. A splinter group from these Siberians were the ones that populated the Americas.
* After the Last Glacial Maximum, a new behaviour appeared– settlement, which is now believed to have occurred before agriculture appeared. During the Bølling-Allerød Interstadial (a warming period, about 15,000 to 12,500 years ago), people moved north again. A second cold period then gripped Eurasia– this period, lasting for 1300 years, was called the Younger Dryas (named after a dwarf yellow rose, Dryas octopetala that grew amid the tundra).
* Sedentism (or settling down) requires new ways of thought, new social relationships, new social organizations. Freedom and equality were traded for hierarchy, officials and chiefs. First clear evidence of long-term settlement is from the Natufians (15,000 to 11,500 years ago) in what is now Israel, Jordan, and Syria. They gathered and stored wild wheat and barley.
* Before settlement appeared there was an amazing worldwide thinning or gracilization of the human skull. This physical change may have accompanied a tamer behaviour, which allowed greater sociability.
* Farming techniques were spread into Europe by Neolithic people from the southern coast of Turkey. They are called the LBK culture, after the pottery– linear band ceramics. The agricultural techniques and the pottery spread into Europe, although the genes did not spread widely, as there was only some gradual mixing with the local people. These people likely introduced the Indo-European languages into Europe. It is believed that large language families originated with the spread of farming.
* In north-central Europe, the Funnel Beaker culture lasted from 6000 to 5000 years ago. They were cattle breeders, and the mutation for lactose toleration first appeared in this population (this mutation helps in the digestion of the lactose in cow’s milk).
* An explanation for religion: religion and language needed each other. Language gave people the power to deceive. "Those who committed themselves in public ritual to the sacred truth were armed against the lie by knowing that they could trust one another." Sanctified statements were an antidote to the misuse of language. There had to be a context in which statements were reliably and indubitably true, and that was sanctity. Later, sanctity was used to bolster the claims of the privileged position of authority figures in the community.