What were the Different systems of classifying organisms?
Classifying organisms is extremely important for studying them.
Some of the classification of organisms, put forth by different scientists, are as follows:
(i) Classification by Aristotle
- Aristotle tried to classify organisms in two major classes: plants and
   Aristotle         Classification of Organisms
- Plants were further classified into three subgroups based on their height – tall, medium, or short as trees, shrubs, and herbs
- Animals were further classified on the basis of their habitat as living on land, living in water, or those able to fly in the
(ii) Classification by Carl Linnaeus
- Carl Linnaeus developed the two kingdom classification system. He also classified organisms into two kingdoms: Kingdom Plantae and Kingdom Animalia
- He further divided the kingdoms into five more levels – class, order, genus, species, and variety.
Carl Linnaeus     Two Kingdom Classification
- Both these systems helped in their own way to classify the various organisms known However, as newer organisms were discovered, it was getting difficult to place them in these two groups.
For example, characteristics of prokaryotes, like structure, presence of cell wall, mode of nutrition, habitat, and so many other parameters raised several questions which remained unanswered with these systems.
- Thus, there emerged the need for developing a new system that could categorise all the various organisms
Prokaryotic cell
- Classification by R. H. Whittaker
- H. Whittaker, an American scientist, came up with an excellent system of classifying organisms.
- He put forth the five kingdom classification system.
