Biological Classification — BIOLOGY STD 11 Science — Question

There are millions of species on this planet. The largest phylum Arthropoda alone comprises of millions of species. To study all of them properly we need some system for categorizing them, based on some common characteristics. Apart from that think of the differences in language and you will find different names for the same species in different languages. In the absence of a system of nomenclature it would have been difficult to share scientific knowledge among the scientists of different nations.
To make things easier and systematic the need for classification was felt. Earlier attempts by people like Aristotle segregated living beings into plants and animals. This was good point to start with, but there are certain living beings which do not fit in either of plants or animals. So a three kingdom classification was devised. The three kingdom classification was used for some time. But as none of the scientific theory is permanent so further discoveries led to creation of a five kingdom classification. The five kingdom classification is the most accepted system of classification.