title: A paradigm gets shifty.
authors.forename: W F
authors.initials: WF
authors.lastname: Doolittle
mesh_terms: D001105:Archaea / Q000378:metabolism; D001419:Bacteria / Q000378:metabolism; D005075:Biological Evolution; D005057:Eukaryotic Cells / Q000378:metabolism; D006859:Hydrogen / Q000378:metabolism*; D008928:Mitochondria; D008954:Models, Biological; D013559:Symbiosis
chemical_list: D006859:Hydrogen