Thursday, September 14 2017
Georgia Tech, EBB 1005
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Metabolic Evolution and the Self-organization of the Biosphere

Metabolism is the biochemical network that supplies the energy and building blocks for all cells on Earth. The collective metabolism of all cells in turn mediates the global biogeochemical cycles, which regulate Earth's climate. Reconstructing metabolic evolution provides a powerful lens for linking evolutionary dynamics across levels of biological organization and for understanding the chemical co-evolution of Earth and the biosphere. I will illustrate these ideas using globally abundant oceanic phytoplankton and co-occurring bacteria as a model system. I will argue the macroevolution of this system drew down nutrients in the surface oceans, thereby increasing total ecosystem biomass, while also increasing levels of dissolved organic carbon. I will further argue this evolutionary dynamic produced a collective mutualism in oceanic microbial ecosystems that is highly similar to that of organelles within plant cells. Finally I will argue that the evolutionary self-organization of oceanic microbial ecosystems contributed to the oxygenation of Earth, and more generally that the rise of atmospheric oxygen reflects an increasing metabolic rate of the biosphere.

Like many people, Rogier Braakman from childhood and into adulthood was fascinated with the questions what are we and how did we come to be. He holds a Master of Sciene in chemistry from the University of Amsterdam, a Ph.D. in chemical physics from Caltech. He has held postdoctoral positions at the Santa Fe Institute and MIT. His journey into science originally lead him to astrochemistry where he hoped that studying networks of organic chemistry occurring during star-formation and leading up to planet formation would lead to general insights about how complex chemical organization emerges from the properties of molecules and reactions, and in particular how life emerged on Earth. From there he was led to biology where he began studying the evolution of metabolism. Dr. Braakman is now studying evolutionary and ecological theory, systems biology, microbiology, oceanography, geochemistry and Earth history.

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