Terrabacteria possess important adaptations such as resistance to environmental hazards (e.g., desiccation, ultraviolet radiation, and high salinity) and oxygenic photosynthesis.

[4] Terrabacteria and Hydrobacteria were inferred to have diverged approximately 3 billion years ago, suggesting that land (continents) had been colonized by prokaryotes at that time.

[2] Together, Terrabacteria and Hydrobacteria form a large group containing 97% of prokaryotes and 99% of all species of Bacteria known by 2009, and placed in the taxon Selabacteria, in allusion to their phototrophic abilities (selas = light).

[2][4] The name “Glidobacteria” [10] included some members of Terrabacteria but excluded the large gram positive groups, Bacillota and Actinomycetota, and is not supported by molecular phylogenetic data.

[13][14][15][16][17][18] Fusobacteriota (sometimes included in Gracilicutes) Synergistota Coprothermobacterota Atribacterota "Fervidibacteria" Dictyoglomota Caldisericota Deinococcota "Acetothermia" Thermotogota "Calescamantes" "Pyropristinus" Aquificota (sometimes included in Gracilicutes) "Margulisbacteria" "Saganbacteria" "Sericytochromatia" "Cyanobacteria" "Melainabacteria" Bacillota (includes Mycoplasmatota) Actinomycetota "Dormibacteraeota" Chloroflexota "Eremiobacteraeota" Armatimonadota "Abditibacteriota" On the other hand, Coleman et al.[4] named the clade composed of Thermotogota, Deinococcota, Synergistota and related as DST and furthermore the analysis suggests that ultra-small bacteria (CPR group) may belong to Terrabacteria being more closely related to Chloroflexota.