Africa and its European and Asian environment, by Jean Jolly


INTRODUCTION

From the origins of Man
to populating Eurasia

From the origins, the history of Man has been conditioned by geography, climate and its environment. To trace this long journey of several thousand kilometres over several million years, we can only rely on the few samples of bones or teeth that have been left to us. As those remains are fragmentary, it is obvious that we can only suggest scenarii that will be discussed and modified depending on new discoveries and technical progress. We have known for several decades that Man and great African apes share part of their history; yet, 10 or 8 million years ago, changes affecting the world as well as the local climates disrupted the distribution of animal life and its evolution. It is probably at that time that great apes and Man separated, as was revealed through recent discoveries in Kenya, Ethiopia and Chad. As a matter of fact, potential hominids were discovered as early as 2000. Yet, the understanding of our origins goes with a better knowledge of our cousins’, the great apes. Between 10 million years and some dozen thousand years back, nothing was known about their ancestry.
However, since 2004, a number of works have filled the blank in our knowledge; for instance, a few teeth found in the Tugen Hills (Kenya), a few others found in the Middle Awash (Ethiopia) or, more recently, half a mandible belonging to a great ape found on the Nakali field (Kenya), have allowed to better understand both dates and differences. Even if those remains are still very few and often fragmentary, they feed our researches with a fantastic hope. The most ancient biped hominids could be traced around 6 million years back, with Orrorin tugenensis whose first remains were unearthed in 2000 in Kenya. Not only did this discovery allow us to push back the difference between great apes and Man (as it was to be confirmed later when Sahelanthropus tchadensis was discovered in Chad and Ardipithecus kadabba in Ethiopia); it also implied that the Australopitheci were not our direct ancestors, but a cousin branch. Imitating the Australopithecus lineage, a more human lineage was developing, that of Man, a being that could move around better on his two legs and progressively giving up arboricultural life.
The most ancient representatives of the human lineage were traced 2,5 million years ago with Homo rudolfensis in Malawi and in Kenya.
However, more ancient men might have existed before, around 4 million years ago (Pracanthropus africanus) and around 3,5 million years back (Kenyanthropus platyaps). More recent representatives of Homo genus (Homo habilis, Homo ergaster, Homo erectus) traditionally known in Eastern Africa (Kenya, Tanzania, Uganda) and in South Africa have also been popular to explain migrations out of Africa towards Eurasia.

The first conquerors

Admittedly, the first men to leave Africa and emigrate to Eurasia were the descendants of Homo erectus. Yet, this scenario has been questioned by extremely ancient settlement traces that were discovered in Europe (notably in the Massif Central or in Eurasia, even though a controversy has arisen over the latter), then by new dating which pushed back the age of Java men. It was clear then those beings more ancient than the well –known erectus must have moved around long before they did. Who could those first conquerors be? Part of the answer has come from Georgia, notably from the Dmanisi site where a human mandible was found in 1991 in levels nearly 1,8 million years old.
Since then, skulls –among which a nearly complete one– have been discovered in that spot. After comparing with Homo erectus from Asia (Sangiran, Zhoukoudian) Homo erectus and/or ergaster from Africa (Kenya, Tanzania, Algeria, Morocco), Homo habilis from Tanzania, Homo rudolfensis from Kenya and some older Europeans, it seems clear that Georgian pieces display characteristics that are akin to those of African species, particularly to some Homo habilis. One could thus figure out a first migration wave of ancient Homo habilis from Africa 2 million years before or even more, which could also account for the existence of ancient Eurasian archaeological sites. Today, the various stages of this history are still rather unknown.
It is nevertheless a certainty that the Dmanisi man, because of his clear geological environment, was the undeniable witness to ancient Eurasian populating. As to the 15 million-year-old fossils from Venta Micena (Spain), they are far from being unanimously acknowledged. There was probably not one migration path only toward Eurasia, since Man moved around and could adapt to extremely diversified environments. The differences that were observed between those sites are not necessarily linked to specific variations, but may be simply due to adaptation. In the wake of initial populating, numerous remains of ancient Homo probably close to Homo erectus can be found: in South Eurasia, notably in Oubeideiya, in Israel, 700 000 years back (possibly 1,4 million years); around 800 000 years back in Italy. He was also acknowledged not long ago in Syria in 550 000-year-old levels and is well-known in Tautavel in France (450 000 years), in Hungary (300 000 years) and in China( between 200 000 and 400 000 years).

The first modern men

Another 780 000-year-old species used to live in Atapuerca (Spain): Homo antecessor who altogether differed from Homo erectus, Homo ergaster and Homo habilis. All those beings might be the result of a series of migrations out of Africa. Whether on the African or Asian continent, there must have been a local transition between Homo erectus and Homo sapiens. Could modern Man have been born in several different places on earth? Some scientists rather agree to his being born in one and the same place (more specially in Africa) from where he should have migrated throughout the world, replacing ancient populations on his way. There are two opposing theories: a unique origin versus a multiregional one. It is all the more difficult to decide as fossils are rare concerning those transition periods and a number of them are difficult to date. However, it seems that a compromise could be reached, implying a migration followed by local crossbreedings; thus, we might have older populations crossing more recent ones. Nevertheless, such hypothesis is far from being universally accepted and the question of the origins of Homo sapiens is dependent on ground discoveries yet to come.
As to first modern men (Homo sapiens sapiens), they appeared in the Near East, about 100 000 years ago, coming perhaps from Africa. The certified existence in Syria of a “typical Homo sapiens industry” 250 000 to 100 000 years back could be the first testimony to a migration corridor toward the rest of the Ancient World. Is Homo sapiens sapiens the only modern being? If we judge from the media announcements from the Flores island, it is not so! This recent paleoanthropologic bolt has resulted in setting scientists against one another. Some of them consider the characteristics of the Flores man ¬–which are different from those of the classical sapiens– evidence of the existence of “a second man”. Actually those men used to live on an island and such island -based beings may show a great variety of features, as was evidenced with the dwarf hippopotamus from Madagascar, the dwarf elephant from the Mediterranean or the giant rabbit from Majorca!
So, a great many debates on our origins and evolution are being held; owing to them science can progress and we can understand our history better and better.

Brigitte Senut


Brigitte Senut is a professor at the Département Histoire de la Terre in the Museum national d’histoire naturelle, in Paris, and a member of the CNRS. For several years, she has been the head of international research group on the origin of Man and the great apes in Eastern and Southern Africa. She plays a major role in the understanding of the dichotomy between Man and the great apes. In collaboration with Herbert Thomas, she has published Les primates, ancêtres de l’Homme.

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