Bacteria

Domain Bacteria: single celled prokaryotic organisms with no membrane bound nucleus, found in essentially every habitat on Earth and inside the bodies of most other living things. Covers the pathogenic, commensal and free living bacterial species catalogued in this atlas, gram positive and gram negative lineages alike, identified by their own sourced description rather than by name. Excludes cyanobacteria: despite sharing the same prokaryotic domain, they stay grouped with Algae and Protists here because they are photosynthetic and were historically classed as blue-green algae, a further split left for a later group-model pass. Excludes archaea, a separate prokaryotic domain with its own distinct cell chemistry, currently unplaced. Pulled out of the former Algae and Protists catch-all because true bacteria are not protists, algae or any kind of eukaryote, and sat there only by mis-filing.