According to the single-origin model, every species of the genus Homo but one, Homo sapiens, was driven extinct. This species had evolved in Eastern Africa between 100,000 and 200,000 years ago and, some time afterwards, in a relatively recent exodus, began colonizing the rest of the world.
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The West African genomes of the Niger Congo and Nilo-Saharan speaking peoples - led to the evolution of the Ivory and West Africa and modern Bantu populations- the smaller groups surviving in the Congo rainforests, the Mbuti and Bayaka pygmy peoples of the Ituri and other Congo rainforests. This group evolved into the genomes of the Cushitic speaking peoples. The warm interglacial and the green Sahara allowed humans living in Ethiopia and the southern Sudan to travel north, crossing the Sinai Peninsula into modern Israel 115,000 years ago. This forms the basis of the Sahul populations found in this area. A sudden freezing of the world’s climates in about 90,000 years ago, saw the return of severe arid conditions to the Middle East, with the loss of major game, and when the dry spell ended. |
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There are two possible routes out of Africa: one is from Egypt, across the Sinai into the Levant. This route is confronted by the major impediment of the arid zone of the Sahara and Sinai deserts. The second route, only opened when sea levels fall is across the Bab-el-Mandeb, between Yemen and Djibouti/Eritrea. This route too is confronted by a barrier, this time the Red Sea and its hazardous reefs, and so is usually only opened when there is a major fall in sea levels. Although, humans must have had ocean-going vessels at least 60,000 years ago to reach Australia, which was separated by a minimum of 80 miles of ocean even at the ocean's lowest level, so it is also possible that humans had vessels capable of crossing a gap of ocean at the strait of Aden not long earlier. |
The African pluvial periods are associated with a wet Sahara phase, in which large lakes and many rivers are found. Flora and fauna previously widespread retreats northwards to the Atlas Mountains, southwards into West Africa, or eastwards into the Nile Valley and thence either south east to the Ethiopian Highlands and Kenya or northwestwards across the Sinai into Asia.
The first signs of iron use come from Ancient Egypt and Sumer, where around 4000 BC. Agriculture in Ireland began around 4500 BC. Sheep, goats, cattle and cereals were imported from Britain and the continent, and the population rose significantly. At the Céide Fields in County Mayo, an extensive Neolithic field system - arguably the oldest in the world - has been preserved beneath a blanket of peat. Consisting of small fields separated from one another by dry-stone walls, the Céide Fields were farmed for several centuries between 3500 of the Naqada culture in Egypt and 3000 BC. Wheat and barley were the principal crops cultivated when the Indus Valley was founded and pottery developed in the Americas.
Newgrange the passage tomb in County Meath was built in 3200 BCE, 600 years earlier than the Great Pyrimid of Giza, 1000 years older than Stonehenge trilithons. According to Irish mythology Newgrange was one of the sidhe or fairy-mounds where the Tuatha Dé Danann lived. It was built by the Dagda, but his son Aengus later tricked him out of it. According to some versions of the story, the hero Cúchulainn was born there. The beginning of the Early Dynastic Period I in Mesopotamia in 2900 B.C. introduced the skekal measurement and came with Ur as one of the richest cities in Sumer. Pottery made its appearance around the same time as agriculture.