Quick revise

The first rank in the classification system is called a kingdom. There are five kingdoms, based upon what an organism's cells are like:

  • animals (all multicellular animals)
  • plants (all green plants)
  • fungi (moulds, mushrooms, yeast)
  • prokaryotes (bacteria, blue-green algae)
  • protoctists (Amoeba, Paramecium).

There are several further ranks before we reach a particular species. In order, these are:

  • kingdom
  • phylum
  • class
  • order
  • family
  • genus
  • species

This video shows the classification hierarchy

Difficulties with Classification

It can be difficult to classify a species e.g. we are Homo Sapiens

rank classification notes
kingdom animals  
phylum chordates animals with backbones
class mammals animals that are warm-blooded, have lungs and body hair, produce milk and give birth to live young
order primates ape-like animals
family hominids human-like animals
genus homo humans
species sapiens modern humans

It can also be difficult to classify a certain organism. For example, the single-celled organism called Euglena has some confusing characteristics. It has:

  • chloroplasts, like a plant
  • no cell wall, like an animal
  • a flagellum to swim with, like some bacteria

A fifth kingdom, called the protoctists, was made for organisms like Euglena.


Average: 5 (2 votes)