C HAPTER . Kingdom Monera . Kingdom Protista . Kingdom Fungi .
Kingdom Plantae . Kingdom Animalia . Viruses, Viroids and Lichens R.H. Whittaker ( ) proposed a Five Kingdom Classification.
The kingdoms defined by him were named Monera, Protista, Fungi, Plantae and Animalia. The main criteria for classification used by him include cell structure, body organisation, mode of nutrition, reproduction and phylogenetic relationships. Table . gives a comparative account of different characteristics of the five kingdoms.
The three-domain system has also been proposed that divides the Kingdom Monera into two domains, leaving the remaining eukaryotic kingdoms in the third domain and thereby a six kingdom classification. You will learn about this system in detail at higher classes. Let us look at this five kingdom classification to understand the issues and considerations that influenced the classification system. Earlier classification systems included bacteria, blue green algae, fungi, mosses, ferns, gymnosperms and the angiosperms under ‘Plants’.
The character that unified this whole kingdom was that all the organisms included had a cell wall in their cells. This placed together groups which widely differed in other characteristics. It brought together the prokaryotic bacteria and the blue green algae ( cyanobacteria) with other groups which were eukaryotic. It also grouped together the unicellular organisms and the multicellular ones, say, for example, Chlamydomonas and Spirogyra were placed together under algae.
The classification did not differentiate between the heterotrophic group – fungi, and the autotrophic green plants, though they also showed a characteristic difference in their walls composition – the fungi had chitin Five Kingdoms Characters Cell type Cell wall Nuclear membrane Body organisation Mode of nutrition Monera Prokaryotic Noncellulosic (Polysaccharide + amino acid) Absent Cellular Autotrophic (chemosyn- thetic and photosynthetic) and Hetero- trophic (sapro- phytic/para- sitic) Protista Eukaryotic Present in some Cellular Autotrophic (Photosyn- thetic) and Hetero- trophic Fungi Eukaryotic with chitin Multiceullar/ loose tissue Heterotrophic (Saprophytic/ Parasitic) Plantae Eukaryotic (cellulose) Tissue/ organ Autotrophic (Photosyn- thetic) Animalia Eukaryotic Absent Tissue/organ/ organ system Heterotrophic ( H o l o z o i c / S a p r o p h y t i c