The ‘East Side Story’ twenty years later

Abstract

The dichotomy between apes and humans is a matter of active debate in palaeontology and should be considered using a holistic approach: time, ecology and anatomy, three interconnected components. Today, it is widely accepted on the basis of neontological data that apes diverged from humans around six million years ago. However, some geneticists have postulated that the divergence may have occurred earlier. The environmental history of hominids has been dominated by the ‘savanna hypothesis’, which suggests that humans emerged in a savanna-like environment, where they became bipedal and used stone tools. One of the most famous outcomes of this hypothesis is the ‘East Side Story’. Despite the fact that this hypothesis is based on three components (geographic, ecological and chronological), the geographic one implied in the name has overshadowed the others in explanations of the dichotomy between apes and humans. The recent discoveries of upper Miocene hominoids in Africa suggest that the geographic aspect is the least important one, whereas the environmental and chronological ingredients can still be considered as crucial factors involved in the divergence between African apes and hominids (hominid being here restricted to the humans and their direct fossil forerunners).