Family trees of ancient bacteria reveal evolutionary moves

Carrine Blank/WUSTL PhotoA WUSTL scientist suggests that Cyanobacteria arose in freshwater environments rather than in the sea.A geomicrobiologist at Washington University in St. Louis has proposed that evolution is the primary driving force in the early Earth’s development rather than physical processes, such as plate tectonics. Carrine Blank, Ph.D., Washington University assistant professor of geomicrobiology in the Department of Earth & Planetary Sciences in Arts & Sciences, studying Cyanobacteria – bacteria that use light, water, and carbon dioxide to produce oxygen and biomass – has concluded that these species got their start on Earth in freshwater systems on continents and gradually evolved to exist in brackish water environments, then higher salt ones, marine and hyper saline (salt crust) environments.