Prokaryotes and Eukaryotes

The organisms that are most primitive or the first to evolve on earth are the bacteria. They do not possess a nuclear membrane around their single chromosome. Absence of a well-defined nucleus terms them prokaryotes (pro means primitive, karyon means nucleus).

All bacteria including blue-green algae (Cyanobacteria) are prokaryotes.

Organisms other than bacteria possessing a well-defined nucleus are eukaryotes (eu means true, karyon means nucleus).

Difference Between Prokaryotes & Eukaryotes