In this section, I am putting forward an alternative theory to the Recent- out-of-Africa theory of origin of homo sapiens, which is currently dominant among paleoanthropologists, I think the case for African origins is actually quite weak, though possible. Repeating it ad-nauseum in the popular press does not make it any more true. As someone has said, there is so little evidence of our complex origins that one can put forward almost anything and have it fit the facts - and here I will do precisely that.
The Recent Out-of Africa theory claims that homo sapiens is a distinct species, that it developed in Africa around 200-120 Kya (Kya=thousands of years ago), and moved out of Africa, following movements of the game animals they hunted - firstly about 90 kya (thousands of years ago) in an unsuccessful excursion into the Levant, and then about 60-50 kya when it moved from Africa along the south coast of Asia all the way to Australia, branching further north into East Asia and finally into the forests of Europe about 35 kya.
The alternative theory I am putting forward is:
1. Our forerunners did in fact develop on the savannas of Africa, but 1.5 Mya they had moved throughout all the lightly treed savannas of Eurasia and Africa, where they may have developed in isolated pockets into groups with rather different characteristics. These forerunners looked essentially like us, except they had a different skull shape, and initially, smaller brains. They used tools and fire, and had been doing so for a very long time. They have been called various names, but they were probably the same biological species as us - homo erectus.
2. From about a million years ago, the Earth began to endure hundred-thousand year cycles of freezing and thawing. The freezing dried the temperate latitudes, creating open grasslands, opened up land bridges and much greater areas of the continental shelf. In the warm cycles, the bridges were inundated, cutting off large groups who were able to develop independently.
3. Probably in the penultimate interglacial, the eemian which occurred about 110 000 years ago (but perhaps earlier in the previous interglacial), two powerful and highly aggressive mutant groups developed in isolated and widely separated areas, both of whom were unlike anything that had gone before, and both of which represented opposite pinnacles of evolutionary development. One subspecies was heavily cold adapted, extremely strong and with unparalleled vision and hand-eye coordination - perfect warriors. These neanderthals probably developed in Scandinavia-Britain which was an island at the time, and expanded southwards as the world cooled and the land passages reopened.
The other subspecies remained warm-adapted and fairly gracile like their African forebears. They had a high degree of social coordination, creative intelligence and command, developing novel technologies after two million years of technological stagnation. These sapiens also initially lived in an isolated area where they needed to establish long trade routes in order to survive - possibly the island chain now known as Indonesia, or perhaps even in Papua and Australia.
4. The two enemies met for the first time in the Levant about 90 Kbp with predictable results - the annihilation of sapiens. It was fortunate that the neanderthal were not well equipped to proceed further into the tropics, and not particularly interested in extending their reach into uncomfortable climates, and it was here they missed their chance at global domination.
5. It was to be another 50 000 years before sapiens, armed with improved technology, much greater numbers and disease resistance, were able to try again in the neanderthal heartland. By this time they had established themselves through the entire tropical and temperate belt, eliminating the original Denisovan inhabitants of Eurasia and the relict populations of Africa - with considerable interbreeding where these were most numerous. They had established large populations in the north of India and in the triangle of the Middle East. They had beaten back the Great Enemy in Siberia, where they learned the techniques for cold survival and outmaneuvering the relatively slow moving neanderthal. In the end, sapiens used exactly the same techniques to wipe out the unbeatable neanderthal that the Europeans were later to use so successfully in eliminating native populations in the New World and Africa - disease, technology and culture, military organisation, and appropriation of resources. They may well have made use of their wealth to invent the divide and conquer tactics that the Romans and Europeans later found so profitable - co-opting one tribal neanderthal group to fight others, and then appropriating the ranges of both parties.
6. It is not entirely true that sapiens wiped out their entire competition through cunning and numbers. They left indications of where these populations once had been numerous by interbreeding - and these show today in the "races" of humanity.
This alternative story, while entertaining, is no more or less fanciful than the current paradigm. In the process of developing it, we will pass through many of the key recent results in paleoanthropology, explaining how they support or fail to support the different scenarios. Even if this story turns out to be largely incorrect, discussing it is instructive and may lead to fresh insights.
The story begins with Homo Erectus Sapiens.
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