Human Evolution and Migration in a Variable Environment: The Amplifier Lakes of East Africa Martin H. Trauth',', Mark A. Maslin", Andreas G.N. Bergner', Alan Deino-, Annett Junginger=', Eric Odada", Daniel O. Olago", Lydia Olaka=', Manfred R. Strecker' 'Institut fur Geowissenschaften, Universitat Potsdam, Potsdam, Germany bGeography Department, University College London, London, UK cBerkeley Geochronology Center, 245 Ridge Road, Berkeley, California 94709, USA dDFG Graduateschool "Shaping the Earth's Surface in a Variable Environment", University of Potsdam <Department of Geology, University of Nairobi, Nairobi, Kenya *corresponding author at Institut fur Geowissenschaften, Universitat Potsdam, Karl-Liebknecht-Str. 24, 14476 Potsdam, Germany. Tel. +49-331-977-5810, Fax +49-331-977-5700, E-mail
[email protected] The development of the Cenozoic East African Rift System (EARS) profoundly re-shaped the landscape and significantly increased the amplitude of short-term environmental response to climate variation. In particular, the development of amplifier lakes in rift basins after three million years ago significantly contributed to the exceptional sensitivity of East Africa to climate change compared to elsewhere on the African continent. These amplifier lakes respond rapidly to moderate, precessional- forced climate shifts, and as they so apply dramatic environmental pressure to the biosphere. Rift basins, when either extremely dry or lake-filled, form important barriers for migration, mixing and competition of different populations