Prokaryote

From Palaeos.org

The prokaryote cell represents the simplest grade of organisation of life, in which the genetic material (DNA) is not gathered together in a nucleus, but distributed throughout the whole cell. Prokaryotes were the earliest life forms on Earth, and they still constitute the bulk of the biomass of life on Earth. The prokaryotes have been on earth for at least 3.85 bya.

There are three domains of life that have or had a prokaryotic grade of organisation: Archaea (Archaeobacteria, which have an anaerobic metabolism), Eubacteria ("true" bacteria and blue-green algae), and the hypothetical Urkaryote organism (which, it is believed, entered into a symbiotic relationship with several different prokaryote species to form the first eukaryote cell.

credits Kheper Site MAK990609, Palaeos com MAK020323, Palaeos org MAK060928