What is the basis of the five kingdom classification proposed by Whittaker?

R. H. Whittaker proposed the five kingdom classification in 1969: Monera, Protista, Fungi, Plantae and Animalia. He based it on several criteria rather than just plant versus animal. The first is cell structure, whether the organism is prokaryotic (no true nucleus, as in Monera) or eukaryotic (true nucleus, the other four kingdoms). The second is body organisation, whether unicellular like Protista or multicellular. The third is the mode of nutrition: autotrophic by photosynthesis as in most plants, or heterotrophic, which is further split into absorptive nutrition in Fungi and ingestive nutrition in Animalia. He also considered phylogenetic relationships, meaning evolutionary lineage. Using these combined features he separated bacteria, single-celled eukaryotes, fungi, plants and animals into distinct kingdoms, which gave a clearer and more natural classification than the older two kingdom system.