In the last twenty-five years, a major research effort has revolutionised our knowledge of the origins of modern humans, the evolution of human diversity, and the demographic parameters associated with both events, making this one of the most exciting topics in prehistory and human evolutionary studies.
A large proportion of that contribution has come from the field of human genetics, with its fast pace of technological development and accumulation of data. However, with the exception of ancient DNA studies, genetics necessarily tells us the story of the survivors of evolution, leaving out of the picture all the populations who became extinct in the process. African human population distributions are very dynamic, as a result of which the history reconstructed from genetic data is either partial, or comparatively shallow. In contrast, recent archaeological research in South and North Africa has revealed the richness and complexity of the early human prehistoric record, although the information is still too limited to allow a continental-level synthesis. Modern humans fossils are the key to bridging the origins with the present, and indeed furnish materials for ancient genomics. However, fossils of Homo sapiens (some just teeth) between 200,000 years ago, the age of the earliest ‘modern-looking’ remains in the continent, and ca. 10,000 years ago are known from only 17 sites throughout all of Africa. This makes it very difficult to build an explanatory framework that begins to address questions about origins, evolution, diversification and differential success of populations.
Our research programme ‘In Africa‘ rests on the strong belief that these questions will only be answered by the discovery of new fossils and archaeological sites. Although new evidence pertaining to the evolution of humans and their diversity anywhere in Africa would be a significant addition to our present knowledge, this project focuses on what happened in East Africa. East Africa, with its tropical climate and complex topography, has had its environmental diversity shaped by localised responses to global climate change, which, in turn, promoted dynamic demographic responses from human groups. Our hypothesis is that East Africa acted as a refugium network for early human populations, not just sustaining occupation through time at a regional level, but also supporting phases of substantial population growth and interaction. The shifting interactions of the refugium network may have provided the key ecological and cultural conditions for the evolution of modern humans to take place.
To test some of these ideas, In Africa is searching for new fossils and prehistoric sites in the Turkana and the Nakuru-Naivasha Basins of the Rift Valley of Kenya. The work in Turkana gives continuity to our earlier project “Late Quaternary Human Evolution in West Turkana“, which found exciting new fossiliferous localities to the southwest of Lake Turkana. The results from the fieldwork in both basins will be used, together with the scientific study of museum collections, to test hypotheses of modern human origins and evolution in the region and the continent. The project hopes to achieve five main goals:
- to increase significantly the number of human and other mammalian fossils in East Africa dating to the last 250,000 years;
- to map changes in human morphology, behaviour and occupation in different basins of East Africa in the period before and after the main modern human dispersals across and out of Africa;
- to map the character and timing of the Middle to Later Stone Age transition in the Central Rift Valley;
- to integrate the human prehistoric record with local palaeoenvironmental data to explore the role climate change and its expression in the African tropics may have played in our recent evolutionary history;
- to increase the scientific and public awareness of how important it is to understand what happened in Africa in order to understand why Homo sapiens and its diversity evolved.