Question

How did Whittaker classify the organism? What was the basis for classification?

Answer 1

Hint: Classification is the process by which we classify different things as categorized based on their properties. Biological classification is a process by which scents have classified different organisms from single-celled unicellular bacteria to the most advanced plants and animals. The scientific term used for these categories is taxa. So we can say various organisms are classified based on their characteristics into different taxa. This process of classification is known as taxonomy.
These categories are called taxonomic categories and are arranged according to their rank together they are called taxonomic hierarchy.
For example, the lion is a mammal and mammals are animals. So lion mammals and animals represent different taxa according to their rank at different levels.

Complete answer:
Earlier organisms were classified into plants and animals but there were certain organisms such as prokaryotes and eukaryotes and some multicellular organisms such as fungi were not belonging to either of those categories.
So, R.H Whittaker(1969) proposed five kingdom classification. These five kingdoms are as follows
-Monera
-Protista
-Fungi
-Plants
-Animals

KINGDOM

PHYLUM

CLASS

ORDER

FAMILY

GENUS

SPECIES

Kingdom monera includes all prokaryotes while kingdom Protista includes all unicellular eukaryotes. Kingdom Protista brings all organisms together that were earlier placed in plants and animals such as Chlamydomonas, Chlorella (were put into Algae within Plants and both having cell walls) and Paramoecium and Amoeba (were put into in the animal kingdom which lack cell wall).

The basis of five kingdom classification are as follows -
-Cell structure
-Body organization
-Mode of nutrition
-Reproduction
-Phylogenetic relationship

Note: In a taxonomic hierarchy, Domain is present which divides kingdom monera into 2 domains and rest all the other eukaryotic organisms are placed into the third domain. And thus there are actually six kingdom classifications.