Born in Africa_ The Quest for the Origins of Human Life - Martin Meredith [88]
Another branch of M 168 known as M 89 moved into western Asia and the Levant, forming an ancestral base from which other groups migrated into the heart of Eurasia, among them M 9. It was the descendants of M 9 who founded a Y-chromosome lineage of ex-Africans that over the next 30,000 years expanded their range to the furthest ends of the earth.
One group—M 175—moved along a northern route to East Asia, joining migrants who had arrived there earlier along a southern route. Another group—M 45—set up a homeland in the steppes of central Asia, whence their descendants diverged in two directions. One branch headed for Siberia and eventually crossed the Beringia land bridge between Siberia and Alaska that led them to the Americas. Another branch—M 173—headed west into Europe, joining other groups who had migrated there from the Levant.
The advance into Europe of modern hunter-gatherers—Cro-Magnons, as they came to be called—made life even more hazardous for nomadic bands of Neanderthals resident there. Over the past 100,000 years, Neanderthals had managed to survive periods of extreme cold, retreating to refuges in warmer southern areas before returning to the north once the ice sheets receded. But now they faced competition for food and shelter from agile newcomers using sophisticated tools, weapons and language skills and organised in large cohesive groups. As genetic research showed, some interbreeding took place: Traces of Neanderthal genes have been found in all non-African genomes. But as Cro-Magnons moved relentlessly westwards across Europe, Neanderthal numbers steadily dwindled. By about 35,000 years ago, they had been reduced to living in isolated pockets in western Europe. By 30,000 years ago, they had all but vanished.
As they spread out across the world, far-flung branches of the modern human family began to diversify, adapting variously to the different climates and ecologies they encountered. Local populations developed distinctive local features. In northern latitudes, they acquired a lighter skin colour in response to different levels of ultraviolet radiation. The diverse trajectories they followed led to a vast array of languages, cultures and religions. New techniques allowed agriculture and settled communities to flourish. Innovation became a way of life.
Thus it was that a group of African hunter-gatherers led humankind to the threshold of a new world.
Glossary
Absolute dating: The process of determining an approximate age for an archaeological or palaeontological site or artefact, usually based on tests of the physical or chemical properties of materials or other items. Methods include carbon dating and potassium-argon dating. Absolute dating techniques contrast with relative dating techniques, such as stratigraphy.
Acheulean: The name given to an archaeological industry of stone tool manufacture, characterised by large bifaces, including hand-axes. It originated in Africa about 1.5 million years ago, spread to parts of western Asia and Europe and continued in use until about 200,000 years ago.
Adaptive radiation: The rapid diversification of species that occurs after an initial evolutionary innovation.
Archaeology: The study of human behaviour and artefacts in history and prehistory.
Ardipithecus: An early hominid genus found in Ethiopia that lived from about 5.8 million to about 4.4 million years ago.
Australopithecines: A subfamily (Australopithecinae) consisting of a single genus (Australopithecus) of extinct hominids that lived from about 4.2 million years ago until about 1 million years ago.
Basalt: A dark, fine-grained volcanic rock.
Biface: A rock core that is flaked on both sides to form a sharp edge around its periphery, such as a hand-axe.
Bipedality: Upright walking on two feet.
Biota: The combined fauna and flora of an area.
Breccia: Rock consisting of angular fragments cemented by finer chalky material. (Italian for ‘broken things’.)
Carbon-14 dating: An absolute dating method, based