Eubacteria

Bacteria Temporal range: Archean or earlier – present Had'n Archean Proterozoic Pha.
Scanning electron micrograph of Escherichia coli rods
Scientific classification
Domain:	Bacteria Woese, Kandler & Wheelis, 1990
Phyla
Gram positive / no outer membrane Actinobacteria (high-G+C) Firmicutes (low-G+C) Tenericutes (no wall) Gram negative / outer membrane present Aquificae Bacteroidetes/Fibrobacteres–Chlorobi (FCB group) Deinococcus-Thermus Fusobacteria Gemmatimonadetes Nitrospirae Planctomycetes–Verrucomicrobia/Chlamydiae (PVC group) Proteobacteria Spirochaetes Synergistetes Unknown / ungrouped Acidobacteria Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Dictyoglomi Thermodesulfobacteria Thermotogae
Synonyms
Eubacteria Woese & Fox, 1977

Actinobacteria (high-G+C)
Firmicutes (low-G+C)
Tenericutes (no wall)

Aquificae
Bacteroidetes/Fibrobacteres–Chlorobi (FCB group)
Deinococcus-Thermus
Fusobacteria
Gemmatimonadetes
Nitrospirae
Planctomycetes–Verrucomicrobia/Chlamydiae (PVC group)
Proteobacteria
Spirochaetes
Synergistetes

Acidobacteria
Chloroflexi
Chrysiogenetes
Cyanobacteria
Deferribacteres
Dictyoglomi
Thermodesulfobacteria
Thermotogae

Eubacteria Woese & Fox, 1977

Bacteria (ⁱ/bækˈtɪəriə/; common noun bacteria, singular bacterium) constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a number of shapes, ranging from spheres to rods and spirals. Bacteria were among the first life forms to appear on Earth, and are present in most of its habitats. Bacteria inhabit soil, water, acidic hot springs, radioactive waste, and the deep portions of Earth's crust. Bacteria also live in symbiotic and parasitic relationships with plants and animals. Most bacteria have not been characterised, and only about half of the bacterial phyla have species that can be grown in the laboratory. The study of bacteria is known as bacteriology, a branch of microbiology.