There are three domains:

• Archae

• Eubacteria

• Eukaryotes

 

All living organisms fall under these domains apart from viruses because they do not count as living organisms. Each of these 3 domains are then further subdivided into the 7 different taxa which include - Kingdom, Phylum, Class, Order, Family, Genus & Species.

 

Domain Archaea

 

This domain is made up of prokaryotes (single celled organisms) which are found in the Archaebacteria Kingdom. Archaebacteria lack nuclei and membrane bound organelles which is why they are known as prokaryotes. Organisms in this domain are found to live in extremely harsh environments that most organisms which are found outside this domain can’t tolerate because of this they are described as extremophiles. They include the extreme halophiles - live in extremely salty conditions, the extreme thermophiles - live in extremely hot condition and lastly the methanogens - these are extreme anaerobes (organism that does not require oxygen for growth) which release methane gas as a waste product. Some examples of organisms found in this domain include Crenarchaeota and Haloarchaea.

 

Domain Eubacteria

 

The Eubacteria domain is also made up of prokaryotic cells and includes the bacteria that people are usually familiar with such as E. Coli which is a harmful disease-causing organisms to the beneficial types of bacteria which can be found in yoghurt, cheese (Lactobacillus bulgaricus). These bacteria lack a nucleus and membrane bound organelles and they have circular DNA which is why they are known as prokaryotes. The domain Eubacteria has one kingdom that it falls under which is known as Eubacteria.

 

Domain Eukaryotic

 

This domain is made up of eukaryotes. Organisms that contain eukaryotes range from yeasts to elephants Eukaryotes contain nuclei, membrane bound organelles and linear DNA. Organisms that contain eukaryotes are divided into 4 main kingdoms which include - Kingdom Protista, Plantae, Fungi and Animalia.