1.5 Homo Sapiens

The next stage in our evolution, the appearance of Homo Sapiens around 200,000 years ago, is shrouded in mystery and some controversy. One theory had him slowly evolving from the various Archaic Homo Sapiens, more or less simultaneously round the old world. The much more likely theory has him evolving only in Africa from a small group of descendants of the African Archaic Homo Sapiens, probably in East Africa. Perhaps, confusingly, some DNA experts suggest that the population of the first Homo Sapiens group grew to about 100,000 individuals, but at some time later, the core group could have fallen rapidly to less than 10,000 for some time, jeopardising its very existence, before its population started to grow again. This “bottlenecking” of the population encourages rapid changes in genetic structure, increasing the pace of evolutionary change. The cause of the reduction could have been the drought in Africa caused by the glacial period that started around 160,000 years ago causing significant periods of desertification, during which time the average world temperature was 5 degrees C cooler than today. A skull has been found in Ethiopia known as “Herto” that is dated to 160,000 years ago and believed to be one of the very earliest examples of Homo Sapiens. This long period of drought was relieved by the Emian interglacial that occurred between 130 and 115,000 years ago when the planet warmed up by a dramatic 5 degrees C in 100 years. During this time Africa became wetter again and the population would have expanded, but the drought then returned. However, the bottleneck may have been some shorter-term traumatic event similar to the eruption of the volcano Toba in Sumatra around 72,000 years ago. This caused parts of India to be buried in ash 10ft deep, the sun to be obscured for several years and global temperature to be depressed for as much as 1000 years, causing great stress on animal and plant life. Whatever the mechanism, one view is that Homo Sapiens walked out of Africa around 75,000 years ago, which, if correct, makes their subsequent population growth and geographic spread breathtaking, as all continents of the world were populated by him, possibly excluding America, by 35,000 years ago.

There are alternative proposals, such as suggestions that Homo Sapiens interbred with the Archaic Homo Sapiens and assimilated them, however, DNA evidence indicates a relatively pure strain with little interbreeding, reinforcing the model of them coming out of Africa. However the question of interbreeding between Homo Sapiens and Neanderthals has recently been reopened and remains unresolved with some DNA evidence suggesting none and other indicating up to 4% Neanderthal DNA in present day humans in some parts of the world, the latter evidence suggesting early interbreeding possibly in the Middle East.

There are also proposals that from as early as 150,000 years ago Homo Sapiens moved out of Africa via the Levant and spread from there round the world. There is a very early burial site in present Israel that is thought to be Homo Sapiens and with the body was a bone and shell necklace with a date claimed to be 100,000 years ago. A more recent report is that tools likely to have been used by Homo Sapiens rather than Neanderthals have been found in Oman on the Arabian Peninsula dated to before 106,000 years ago.

To explain the conflicting evidence it is possible that there was more than one wave of Homo Sapiens coming out of Africa, as there are examples of co-existence between him and Archaic Homo Sapiens. For example, there is some evidence that both Neanderthals and Homo Sapiens lived in the Middle East from 100,000 to around 50,000 years ago. They may well have met or possibly could have lived in the same area at different times, as the temperature changed, with Neanderthals being more tolerant of the cold. After this time Neanderthals receded westwards to become extinct, probably in Gibraltar, possibly as late as 24,000 years ago, around the time of a particularly cold event in the last glacial period when the temperature dropped some 10 degrees C in less than 50 years.

From the best evidence available today, the model of Homo Sapiens coming out of Africa between 100,000 and 75,000 years ago is the most likely. Of course they continually adapted and evolved, but early Homo Sapiens was certainly similar to modern man, and from about 35,000 years ago was, from a skeletal point of view, virtually indistinguishable from him.

Homo Sapiens also brought with them new stone tools some of which have been found in Africa from around 130,000 years ago. Tangs to fasten stone heads to handles were found in the Saharan area dated to 70,000 years ago. Bows and arrows were apparently invented more than once, but stone arrowheads have been found in Angola dated to 30,000 years ago. Wooden arrows would have been used long before this.