Write in brief about progressive changes in animal classification?

Explanation

(i)There are nearly seven million different species of animals which show a lot of diversity. Hence, it is impossible to study them together.
(ii)Many scientists tried to classify animals into various groups .
(iii)Greek philosopher Aristotle was the first to perform animal classification.
(iv)Aristotle classified animals according to the
criteria like body size, habits and habitats. Classification proposed by Aristotle is known as 'Artificial method'.
(v)Besides Aristotle, the 'Artificial method' was
followed by Theophrastus, Pliny, John Ray, Linnaeus, etc. later on 'Natural system of classification' was followed.
(vi)'Natural system of classification' was based on various criteria like body organization, types of cells, chromosomes, bio-chemical properties etc.
(vii)With time, system of classification based on evolution was also brought into practice. It was used by Dobzhansky and Meyer.
(viii)Recently, Carl Woese has proposed the animal classification. In this way, the classification methods of animals shows progressive changes.