Five-Kingdom System Classification

Classification systems is introduced by taxonomists include two-kingdom, three-kingdom, four-kingdom, five-kingdom, and six-kingdom systems.

In two-kingdom system classification, organisms are classified into Kingdom Plantae (Plants) and Animalia (animals). Organisms included into Kingdom Plantae have rigid cell walls since they are composed of cellulose and capable to photosynthesize. Organisms included into Kingdom Animalia are organisms having capability to actively move from one location to another.


In the next development, fungi those were initially included into Kingdom Plantae can not photosynthesize. Therefore, classification system by the way obtaining nutrition (food) was created. In this system, organisms are classified into three kingdoms, namely Kingdom Plantae, Kingdom Animalia, and Kingdom Fungi. Kingdom Plantae (plants) is which its members are photosynthesizing organisms. Members of Kingdom Animalia (animals) are phagotrophic organisms, that is heterotrophic organisms swallowing food in solid form. Members of Kingdom Fungi (fungi) are organisms decomposing their habitats as well as absorbing them.

The development of biology proves that there are any organisms where their cell nuclei have no membranes with the result that their cell nuclei materials are spread all over cytoplasm. Such cells are called prokaryotic. Organisms having such cells are called prokaryote. Any cell with its cell nucleus having nucleus membrane is called eukaryotic cell. Organisms having such cells are called eukaryote. And then, four-kingdom system classification was established. This system includes Kingdom Monera having members of prokaryotic organisms and Kingdom Fungi, Plantae, and Animalia having members of eukaryotic organisms

In 1969, Robert H. Whittaker introduced five-kingdom system classification by considering levels of organisms, cell, and kinds of nutrition. The five kingdoms are as follows.

1. Monera, prokaryotic organisms, consisting of bacteria and green-blue algae.
   [Read The Detail]
2. Protista (protists), eukaryotic organisms including Protozoa and algae. [Read The Detail]
3. Fungi, multicellular eukaryotic organisms and they decompose their food and absorb it. [Read The Detail]
4. Plantae (plants), multicellular eukaryotic oganisms that can photosynthesize including Bryophyta (moss), Pteridophyta (fern), and Spermatophyta (plants those produce seeds).
5. Animalia (animals), heterotrophic multicellular eukaryotic organisms including, among other things Porifera (sponges), Coelentarata (animals having hollow body cavities), Vermes (worms), Mollusca (mollusc), and Echinodermata (animals having skinny skins)

Afterwards, we found that virus can reproduce as a characteristic of organisms. Therefore, Robert H. Whittaker added Kingdom Virus into the five kingdoms he already introduced. Currently popular classification system is five-kingdom system classification.

Tweet