Prokaryo(n)tes

Organisms in which the genetic material of the cells is organised in the form of a pronucleus; this is not separated from the cytoplasm by a nuclear membrane. cytoplasm with a nuclear membrane.

Today, a distinction is made between the primordial kingdom (or domain) of "true" bacteria(Bacteria) in the narrower sense, and the primordial kingdom of archaebacteria(Archaea), which comprises a series of highly specialised organisms that live under the most extreme conditions.