System of Classification
Based on the number of living organisms present on Earth, not to mention the various types of them, it is utterly impossible to identify them without a proper classification system. Therefore, to make things more organized and easy to understand, the classification system was introduced in all fields. This led to the classification of organized kingdoms of organisms.
Robert Whittaker introduced the five kingdom classifications of organisms based on the cell structures, body structures, mode of obtaining nutrition, thallus organization, reproduction, and phylogenetic relationships. The various kingdoms were differentiated on the following basis:
- Kingdom Monera- includes prokaryotes.
- Kingdom Protista- includes unicellular eukaryotes.
- Kingdom Fungi- includes fungi.
- Kingdom Plantae- includes multicellular eukaryotic plants.
- Kingdom Animalia- includes multicellular animals.