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The Five Kingdoms Classification System

All living things can be grouped into five categories. This is called the five-kingdom proposal and was introduced by Robert Whittaker in 1968 as a way to categorise all organisms.

Living organisms are divided into the five kingdoms:

  • Prokaryotae
  • Protoctista
  • Fungi
  • Plantae
  • Animalia


  • Unicellular and Microscopic.
  • Non-membrane bound (no nuclear membrane, no ER, no mitochondia).
  • Cell wall made of murein.
  • Examples: Bacteria or Cyanobacteria (photosynthesising bacteria).


  • Mainly small eukaryotic organisms.
  • Many live in aquatic environments.
  • This is usually the kingdom where organisms which aren’t animals, plants or fungi go.
  • Examples: Algae, slime moulds and the malaria causing Plasmodium.


  • Eukaryotic
  • Multicellular
  • Cell wall made of chitin.
  • The members of this kingdom don’t possess photosynthetic pigments and are therefore heterotrophic.
  • Examples: Mushroom, Mold, Puffball


  • Eukaryotic
  • Multicellular
  • Cell wall made of cellulose.
  • Members of the plantae group contain photosynthetic pigment and gain their energy through it and are therefore autotrophic.


  • Eukaryotic
  • Multicellular
  • Heterotropic
  • The members of this kingdom can be split into two groups, vertebrates and invertebrates. The diagram below shows the different subsections of the animalia
Illustration showing the five kingdoms of organisms on earth

The vertebrate subsection of the animalia kingdom can be split again into five different sections:

  • Fish
  • Amphibians
  • Reptiles
  • Birds
  • Mammals
KingdomNumber of CellsType of CellsHow do they gain their energy?Do they move?Examples
ProkaryotesUnicellularProkaryoticSome Heterotrophic, Some AutotrophicSomeBacteria, Cyanobacteria
ProtoctistaMainly UnicellularEukaryoticSome Heterotrophic, Some AutotrophicSomeAmoeba
FungiMulticellularEukaryoticHeterotrophicMainly notMushroom, Mold, Puffball
PlantaeMulticellularEukaryoticAutotrophicNoTrees, Flowering Plants
AnimaliaMulticellularEukaryoticHeterotrophicYesBird, Human, Cow

Read more about Biomass

Frequently Asked Questions

What is the five kingdom classification system?

The five kingdom classification system divides all the organisms into five groups which are plants, animals, protists, prokaryotes and fungi.

Who proposed the five kingdom classification system?

Robert Whittaker proposed the five kingdom classification system in 1968. It’s the most effective and accurate way of classifying organisms.

What are the advantages of the five kingdom classification system?

This classification system is quite useful in biological studies as it separates prokaryotes from eukaryotes and autotrophs from heterotrophs and places fungi in a separate group as their mode of nutrition and cell wall characteristics differ from the others.

What is the drawback of the five kingdom classification system?

This system has no space for acellular organisms such as viruses.