... of the economy at Birimi, a settlement close to the northern edge of the West African forest in modern Ghana. This was an outlier of the Kintampo culture whose other sites, further south in the ... while others moved more quickly up the main waterways until, at about 1000 bc, they reached the eastern edge of the equatorial forest in the broad area of the great East African lakes. There they ... eight million years ago with the separation of the hominins (ancestral to human beings) from their closest animal relatives, the ancestors of the chimpanzees. The skull of the first known hominin,...