CLASSIFICATION OF ORGANISMS

The classification of living things is called "Taxonomy." Living organisms are classified into 

• Domains - This includes Archea, Eubacteria, Eukaryote. Domains are classified into five kingdoms.
• Kingdom is then split into smaller groups, called Phyla (singular is Phylum).
• Phylum is split into smaller groups called Classes.
• Class is split into Orders, 
• Order is split into Families
• Family is split into Genera (singular is Genus).
• Genus is split into Species.
• Species is a single organism, not a group.

This results in eight types of groups in order from largest to smallest as shown above. This is known as the Linnaean classification system.

Eubacteria are bacteria, made up of small cells, which differ in appearance from the organisms in the above kingdoms. They lack a nucleus and cell organelles. They have cell walls made of peptidoglycan.

Archae (or Archaebacteria) are bacteria which live in extreme environments, such as salt lakes or hot, acidic springs. These bacteria have unique properties and features such as unusual lipids that are not found in any other organism. Their cell walls lack peptidoglycan.

The five kingdoms:

• Animalia (Animal) - This includes sponges, worms, insects, fish, amphibians, reptiles, birds, and mammals.
• Plantae (Plant) -This includes mosses, ferns, woody and non-woody flowering plants.
• Fungi -This includes fungus, molds, mushrooms, yeasts, mildews, and smuts.
• Protist - This includes protozoans and algae of various types.
• Monera - This includes bacteria, blue-green algae (cyanobacteria), and spirochetes.

Binomial nomenclature is used to name an organism. The first word beginning with a capital is the genus of the organism and the second word beginning with lower-case letter is the species of the organism. The scientific name can be also abbreviated, where the genus is shortened to only its first letter followed by a period. For example, Lepus europaeus can be written as L. europaeus. 

                   Homo sapien can be written as H. sapien

What are Eukaryotes? 

They are cells that are complex in structure, with nuclei and membrane-bound organelles. Examples are the animal and plant cells.

What are  Prokaryotes? 

Prokaryotes are the smallest and simplest type of cells, without a true nucleus and no membrane-bound organelles.

Examples are the bacteria and viruses.