The Olorgesailie Drilling Project is the undertaking to analyze ancient lake sediments in eastern Africa in order to obtain long climate records in the areas once inhabited by early hominins. Led by Dr. Rick Potts, director of the Smithsonian Institution's Human Origins Program, in cooperation with the National Museums of Kenya, the project has obtained a core sampling of sediments that reflect changes in climate over a span of 500,000 years. The working theory behind the project is that climate change itself--variations in rainfall, temperature, vegetation, and environmental stressors such as fluctuations in available sources of food--a has been a major driver of evolution, continuously creating new circumstances to which human ancestors had to adapt.