A new five kingdom classification system was given by R.H. Whittaker on the basis of following four criteria.
(1) Complexity of cell structure (prokaryotic or eukaryotic)
(2) Complexity of body structure (unicellular or multicellular)
(3) Mode of nutrition-autotrophic (photosynthesis) and-Heterotrophic (absorption and ingestion)
(4) Major ecological role (Producer, Decomposer and Consumer)