• Explain five kingdoms as proposed by Whittaker?
• What modification was introduced by Carl Woese?
• How further classification was done for various organisms?

R.H. Whittaker proposed a five kingdom classification of living organisms on the basis of Linnaeus’ system of classification. The five kingdoms proposed by Whittaker are Monera, Protista, Fungi, Plantae, and Animalia.

The basis for grouping organisms into five kingdoms is as follows:

(i) On the basis of the presence or absence of membrane-bound organelles, all living organisms are divided into two broad categories of eukaryotes and prokaryotes. This division lead to the formation of kingdom Monera, which includes all prokaryotes.

(ii) Then, eukaryotes are divided as unicellular and multicellular, on the basis of cellularity. Unicellular eukaryotes form kingdom Protista, and multicellular eukaryotes form kingdom Fungi, Plantae, and Animalia.

(iii) Animals are then separated on the basis of the absence of a cell wall.

(iv) Since fungi and plants both contain a cell wall, they are separated into different kingdoms on the basis of their modes of nutrition. Fungi have saprophytic mode of nutrition, whereas plants have autotrophic mode of nutrition. This results in the formation of the five kingdoms.




2 CARL WOESE  introduced a modification in Whittaker classification by dividing Monera into Archaebacteria and Eubacteria.

3

Further classification is done by naming the sub groups at various levels as given below:

• Kingdom
• phylum(for animals)/ Divison (for plants)
• Class 
• Order
• Family 
• Genus
• Species

This is termed as the Hierarchy of Classification