Before revision: Chlorobi (green sulfur bacteria) Type I Heliobacteria Type I Chloracidobacterium Type I Proteobacteria (purple sulfur bacteria and purple non-sulfur bacteria) Type II Chloroflexota (green non-sulfur bacteria) Type II Gemmatimonadota Type II Eremiobacterota Type II Cyanobacteria and the evolution of photosynthesis The biochemical capacity to use water as the source for electrons in photosynthesis evolved once, in a common ancestor of extant cyanobacteria (formerly called blue-green algae).
After revision: (see: Purple bacteria)Chlorobi (green sulfur bacteria) Type I Heliobacteria Type I Chloracidobacterium Type I Proteobacteria (purple sulfur bacteria and purple non-sulfur bacteria) Type II Chloroflexota (green non-sulfur bacteria) Type II Gemmatimonadota Type II Eremiobacterota Type II Cyanobacteria and the evolution of photosynthesis The biochemical capacity to use water as the source for electrons in photosynthesis evolved once, in a common ancestor of extant cyanobacteria (formerly called blue-green algae).