The distribution of bioenergetic modes across taxonomic lineages suggests rampant horizontal gene transfer, or multiple independent origins.

He: heterotrophs/respiration.OP: oxygenic photosynthesis.AP: anoxygenic photosynthesis.Me: methanogenesis.SR/AR: sulfate/arsenate reduction.Sfr: sulfur reduction.SO: sulfur oxidation.FR: iron reduction.FO: iron oxidation.a = lineages represented by only one species are shown in bold and the species name abbreviation is given.b = only found in bacteria.c = only found in the archaea.d = ancient origin assumed (patchy distribution likely due to secondary loss, but see [37]).e = assuming a common origin for the subgroups of the proteobacteria.f = ancient origin before common ancestor of the crenarchaea.g = assuming a common origin for the archaeglobi, the thermoplasmata and Ac_booFO.h = assuming one origin.The distribution of bioenergetic modes across taxonomic lineages suggests rampant horizontal gene transfer, or multiple independent origins.