Question

Write in brief about progressive changes i
animal classification........​

Answer 1

Answer:

Animals are multicellular eukaryotic organisms that form the biological kingdom Animalia. With few exceptions, animals consume organic material, breathe oxygen, are able to move, can reproduce sexually, and grow from a hollow sphere of cells, the blastula, during embryonic development. Over 1.5 million living animal species have been described—of which around 1 million are insects—but it has been estimated there are over 7 million animal species in total. Animals range in length from 8.5 millionths of a metre to 33.6 metres (110 ft). They have complex interactions with each other and their environments, forming intricate food webs. The kingdom Animalia includes humans, but in colloquial use the term animal often refers only to non-human animals. The study of non-human animals is known as zoology.

Answer 2

Explanation:

i. Greek philosopher Aristotle was the first to perform the animal classification. He classified the animals according to the criteria like body size, habits and habitats. It is known as ‘Artificial method’.

ii. Besides Aristotle, artificial method of classification was followed by Theophrastus, Pliny, John Ray, Linnaeus, etc.

iii. Later on, ‘Natural system of classification’ was followed. Natural system of classification was based on various criteria like body organization, types of cells, chromosomes, bio-chemical properties, etc. Dobzhansky and Meyer propagated the use of system of classification based on evolution.

iv. Recently, Carl Woese has also proposed the animal classification. This system of animal classification was in practice till now.

v. At present, according to the five kingdom classification system of Robert Whittaker, all multicellular animals are included in Kingdom: Animalia. This system of classification is based upon some criteria like Body organization, Body symmetry, Body cavity, Germinal layers, Segmentation, etc.

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