Middle Pleistocene diversification

The first departure from Africa, around 1.8 million years ago, was most probably made by populations of primitiveHomo erectus . These men had achieved a biological and behavioral model quite different from that of their predecessors. Their predatory activity, linked to a diet with a strong meat component, is clearly evident in the archaeological record, with sites that combine lithic industries and the remains of hunted or scavenged fauna. They were adapted to living in treeless areas. Their material culture includes the first Acheulean forms as early as 1.75 million years ago. It was undoubtedly the development of a truly "human" adaptive niche that enabled these forms to expand out of Africa into southern Eurasia. Traces of these first occupations do not go beyond 40° north latitude. It was only much later that humans colonized more northerly regions. In mid-latitudes, their dispersal was punctuated by the climatic oscillations of glacial/interglacial cycles, which profoundly altered the landscapes, fauna and geography of the European continent. These fluctuations have had a direct influence on the possibilities for population exchanges between different regions and on settlement densities. In Africa and the Near East, with a different periodicity, it is above all the degree of aridity and the extension of deserts, first and foremost the Sahara, that have varied.