Question

Highlight the criteria used for five kingdom system of classification.

Answer 1

Robert H. Whittaker in 1969 gave the five kingdom system of classification. These five kingdoms are- Monera, Protista, Fungi, Plantae, and Animalia. This classification was based on following factors-

1. Structure of cells: Living organisms can be divided into two main categories on the basis of cell structure-

a) Prokaryotic ( cells lacking well-organized nucleus and other membrane-bound organelles)

b) Eukaryotes ( cells having well-organized nucleus and other organelles)

2. Complexity of organism-

a) Unicellular (organisms having single cell)

b) Multicellular ( organisms consisting of more than one cell in their body)

3. Mode of nutrition: Organisms were divided into -

a) Autotrophic i.e. that can make their own food with the help of light (phototrophs) or with the help of chemical compounds (chemotrophs).

b) Hetrotrophic i.e that can not make their own food and depend on plants or other animals for food.

4. Phylogenetic relationship- Phylogeny means the evolutionary history of an organism. This feature shows the direction of evolution of organisms.

5. Ecological role of organisms was also considered and the organisms were divided into producers, consumers, and decomposers.