How has life shaped Earth—and how has Earth shaped life?
Earth scientists have a tendency to view Earth’s geological evolution as a fundamentally inorganic process. Life scientists, in the same spirit, tend to regard the evolution of life as a fundamentally biological issue. Yet the development of life has clearly been influenced by the conditions of Earth’s surface, while Earth’s surface has been influenced by the activities of life forms. The atmosphere would not contain oxygen if it were not for life, and the presence of oxygen has enabled other types of life to evolve. We know that geological events and meteoroid impacts have caused massive extinctions in the past and influenced the course of evolution. But the exact ties between geology and evolution are still elusive. On the modern Earth we are interested in the role of life in geological processes like weathering and erosion. And we seek to understand how life may have manifested itself and left traces preserved in the geological records of other planets. • Can earthquakes, volcanic e
