Photosynthetic bacteria, aerobic prokaryotes

Fig. 2. An evolution diagram illustrating a suggestion of common ancestry of some present-day organisms. The essential features of present-day photosynthesis may have originated in the prebiotic era and is preserved in its most primitive form in (at least some) present-day phototrophs. The heterotrophs may have developed parallel with the aerobic nonphotosynthetic bacteria, some l to 1.5 x 109 years after the emergence of the cyanobacteria. The eukaryotic photosynthetic organisms developed much later, perhaps some 1.5 to 0.5 x 109 years ago. The archaebacteria are primitive organisms that seem to have no evolutionary relation with the present prokaryotes.21 Little is known about their energy metabolism. Tentatively, they are considered as a very early form of cellular life.

Prokaryote domain (EU) BACTERIA PROTEOBACTERIA Gram-negative bacteria, primitively photosynthetic or chemolithotrophic, with several groups that developed aerobic respiration original source of mitochondria of eukaryotes includes anaerobic PA, chemo-autotrophs (e.g. ammonium oxidisers), oxygen or nitrate respiring H pseudomonads Nitromonas, Pseudomonas... 

The endosymbiotic theory of the origin of eukaryotes states that eukaryotes arose from symbiotic groups of prokaryotic cells. According to this theory, smaller prokaryotes lived within larger prokaryotic cells, eventually evolving into chloroplasts and mitochondria. Chloroplasts are the descendant of photosynthetic prokaryotes and mitochondria are likely to be the descendants of bacteria that were aerobic heterotrophs. Serial endosymbiosis is a sequence of endosymbiotic events. Serial endosymbiosis may also play a role in the progression of life forms to become eukaryotes. 

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