East side story: the origin of humankind.

Humans are creatures whose roots lie in the animals. Accordingly, we find ourselves at the tip of one of the branches of an immense tree of life, a tree that has been developing and growing ever more diverse over a period of four billion years. From an evolutionary standpoint, it is important to locate the place and the time that our branch separated from the rest of the tree. It is these questions that the present article attempts to answer. When, where and why did the branch that led to us, the genus Homo, diverge from the branch that led to ouT dosest cousin, the genus Pan, or the chimpanzee? Because this parting of the ways seems to unfold several million years before Homo, properly speaking, was born, the issue of our precise origin also needs to be addressed. When, where and why did Homo appear in the bosom of a family, Hominidae, that was well planted in its ecosystem and well adapted to its environment? I first realized in 1981 that it might be possible to find answers to these questions. The occasion was an international conference in Paris organized by UNESCO to celebrate the 100-year anniversary of the birth of Pierre Teil-