Shortcommings Of Two kingdoms Classification

The history of taxonomy of organisms shows that the taxonomist always tried to classify the living organisms into two organisms into two distinct kingdoms Plantae and Animalia. Hence, these system of classification are known as two kingdom system.

1. Plantae : It includes all the organisms which show :

i) Autotrophic nutrition.

ii) Sedentary habitat (fixed in a place).

iii) Presence of cellulose cell wall.

iv) spread out appearance.

It includes all the green plants, mosses, fungi, lichens, bacteria.

2. Animalia : It includes all the organisms which show

i) Heterotropic nutrition

ii) Locomotion

iii) Absence of cellulose cell wall.

It included all unicellular and multicellular animals. The grouping of such diverse organism into two kingdoms has appeared unsatisfactory to many biologists.

a) It puts together eukaryotes (organisms with true nucleus in their cells) with prokaryotes (organisms without true nucleus)

b) It placed non-photosynthetic fungi together with photosynthetic fungi together with photosynthetic green plants.

c) Many singled celled animals like euglena have features of both plants and animals.

d) Some unicellular organisms like slime moulds lack a cell wall in the vegetative stage but develop one during the reproduction stage.

e) Bacteria could not be classified as plants or animals.