R H Whittaker (1969), an American taxonomist divided all the organisms into five kingdoms. These are kingdom-Monera, Protista, Fungi, Plantae and Animalia, of these kingdom monera contains prokaryotic organisms whereas rest four kingdoms contain eukaryotic organisms. Out of these five, only one kingdom-Monera contains all prokaryotes like, bacteria mycoplasma, Actinomycetes and blue-green algae (cyanobacteria). Rest four kingdoms Protista, Fungi, Plantae and Animalia ie, contain unicellular (Protista) to multicellular (Fungi, Plantae and Animalia) eukaryotic cell organization.