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Published on Jul 26, 2011
In 1969, Carl Woese began using molecular sequences of RNA to study the evolutionary history of life on Earth, eventually determining the first "Tree of Life." This project led, in 1977, to the discovery of a third branch of life: the Archaea -- microorganisms distinct from Bacteria (which they resemble) and Eukaryotes (plants and animals). The concepts and discoveries emanating from this work have transformed biology, particularly evolution, ecology and microbiology.