Biological Classification - Five Kingdom
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Description:
Five kingdom system of classification was developed by R.H Whittaker in 1969. He used five criteria for delimiting the different kingdoms.
- Complexity of cell structure − prokaryotic and eukaryotic.
- Complexity of body structure or structural organization: unicellular and multicellular.
- Mode of nutrition − autotrophic and heterotrophic.
- Mode of reproduction − Sexual and asexual
- Phylogenetic relationships.
Factors that lead to the development of five kingdom classification system.
On the basis of presence of cell wall, bacteria, blue green algae, fungi, mosses, ferns, gymnosperms and angiosperms were considered under plantae.
The earlier systems grouped both unicellular and multicellular organisms into the same group.
Fungi and plants were present in the same group though they had differences in their cell wall composition.
Attempt was made to consider not only morphological, physiological and reproductive similarities but also phylogenetic i.e. evolutionary relationships.
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