Summary:
- Prokaryotes are single-celled organisms that lack a nucleus.
- They also lack other membrane-bound organelles.
- The first cells and organisms to evolve would be classified as prokaryotic.
- Prokaryote domains are Bacteria and Archaea.
- The third domain is Eukarya.
- It includes all eukaryotes.
- Archaea were once thought to be offshoots of Bacteria that were adapted to extreme environments.
- Scientists now know that Archaea share several traits with eukarya that Bacteria do not.