History of Earth and Life

How did life on the early Earth begin, and evolve? What geologic or geochemical evidence of that life is recorded? How did life’s presence fundamentally change the Earth? How have life and the Earth changed together over the eons? Caltech geobiologists explore such questions through a combination of work on modern organisms, reconstruction of phylogenetic histories, and direct examination of the geologic record. Recent examples of related projects:

  • Studies of chemical and isotopic traces from ~600 million-year-old rocks in Oman that were deposited just before the Cambrian explosion of animal life, or of 3.4 billion-year-old rocks of the Strelly Pool formation in Australia that represent some of the earliest glimpses of life (Grotzinger, Fischer, Sessions)
  • The origins of oxygenic photosynthesis and its relationship to banded iron formations and giant manganese deposits (Fisher, Kirschvink)