I study general principles of metabolic evolution, and take a chemical physics perspective on questions of macroevolution, ecosystem self-assembly and Earth history. I use comparative genomics to reconstruct the evolution of metabolic networks over geologic timescales, and combine this with information from other levels to understand the nature, drivers and ecological/environmental consequences of innovations. My ultimate goal is to understand the logic that underpins the chemical organization of life across levels of the biosphere, and how chemistry constrains the co-evolution of Earth and the biosphere.