Why did our ancestors leave Africa?

How primitive man came to Europe from Africa

There is no dispute about the basic questions: How a person became a person - and when.

"We know that modern man Homo Sapiens arose in East Africa around 200,000 years ago, from two independent sources. One from paleontology, that is, from studying the fossils themselves. Fossil finds indicate that the oldest examples of modern man have been found in Ethiopia and we have a number of the next younger fossils across the Middle East to Europe, that would be the one basis. "

The other basis on which Jürgen Richter's research rests is genetics: From DNA comparisons we know that people today have a common root in Eastern Africa. How our ancestors found their way to Europe is still completely unclear. Richter, professor of prehistoric archeology at the University of Cologne, finally wants to find out more precisely with a large interdisciplinary team. The German Research Foundation will now support this basic project in a new "Collaborative Research Center".

"When you look at the expansion models of modern man, you actually always see maps with arrows on them. And that's a thing that I don't want to see one-sidedly, but supplemented by areas, by regions in which people lived. "

The arrows on the maps suggest that groups of people would have purposefully migrated up to Europe:

"Maybe under the leadership of a chief who says: This way!"

More plausible, however, is the idea that early modern humans gradually moved from one region to the next. That they always found a new home and lived there until one day - after how many generations? - set out again and moved on. Richter wants to examine these habitats with their advantages and disadvantages.

He has no doubts about the spread from East Africa to the Middle East, then through Turkey and the Balkans to Central Europe. But there is also another, western route from Africa to Europe: The route from Morocco across the Strait of Gibraltar.

"At the moment it looks like the western route has not been used or has only been used very late by modern man. But one must not forget that this state of research is very, very fragile. It is based on very few Neanderthal sites in southern Spain. On very few dated objects - where new dating series alone could change the picture. "

And why did people leave East Africa in the first place? This question must also be answered by anyone who wants to research the spread of humans from the ground up. This shows once again: Although we know fossils of early humans themselves, we know next to nothing about their living conditions - about plants, animals and the climate in East Africa 200,000 to 100,000 years ago.

In order to obtain data on this, Jürgen Richter brought geologists and mineralogists who specialize in sediment drilling into the team.

"You drill holes in so-called finely laminated sediments. For example, in freshwater lakes in which you have seasonal deposits with very fine annual stratifications, sometimes also seasonal stratifications, for example spring-autumn stratifications, which you can then count down to the year You a very precise date of what is stored in the layers. "

And this material provides information about living conditions: For example, certain chemical elements can be used to determine the climate. Or the pollen from plants that are thousands of years old has been preserved in the bottom of the lakes. And ash remains give evidence of volcanic eruptions.

Geographers are supposed to complement the picture by reconstructing the former landscape of East Africa. Archaeologists will search for settlement sites, tools, weapons and scraps of food from early modern man. The focus of the work, however, will be the reconstruction of the climate: Today, researchers usually see a change in the climate as the cause of great migration movements - whether in the dark past or in more recent centuries, when historians were already recording names and deeds.

Jürgen Richter suspects that the end of the warm period around 200,000 years ago could have triggered the migration of modern man: Perhaps this was associated with an increase in population, perhaps the larger groups of people had to develop new livelihoods. Here, too - in an ethnological project - basic research is still to be carried out, because so far only individual cases have been examined.

"For example, here in Central Europe, if you look back in prehistoric times, it becomes clear that hunter-gatherer populations have grown just when it has become a little cooler, namely when the short-lived steppe grasses have spread more, which in turn form the basis of life for the ungulates, which of course have become very important for humans as a meat supplier. "

Modern man developed around 200,000 years ago - but a lot of time passed before dynamism came into human history. It was only around 40,000 to 30,000 years ago that humans made great cultural advances: better hunting weapons were invented and the first known works of art were created. In this phase the Homo Sapiens Sapiens ousted its competitor in Central Europe, the Neanderthal. And it was precisely at this time that strong, rapid climatic fluctuations occurred - a coincidence?

"We think that this must be the key for very strong population fluctuations, both in Neanderthals and in modern people, and that this situation gives rise to the population advantage for modern people. We simply suspect a large population growth that then turns into a social one Consolidation led, perhaps larger group sizes, so that technological innovations would have been better preserved and the whole cultural dynamic would have got off to a better start - but that, too, is a working hypothesis at the moment. "