Classification refers to the identification, naming, and grouping of organisms into a formal system based on similarities in their internal and external structure or evolutionary history. It determines the methods of organizing diversity of life on earth. Therefore, classification helps in understanding millions of life forms in detail. Who started the classification of organisms? Let us explore the history of classification. History of classification
One of the earliest schemes of classification was given by the Greek thinker, Aristotle, around 300 BC. He classified animals according to their habitat – land, air, or water. However, this classification of Aristotle was misleading because animals that live on land include earthworms, mosquitoes, butterflies, rats, elephants, tigers etc. These animals do not resemble each other except that they share a common habitat. Similarly, all aquatic animals do not resemble each other.
Therefore, a new system of classification was developed to classify the vast diversity of organisms present on earth. Principles of classification followed today include:
• Nature of cell: Nature of the cell is considered to be the fundamental feature, as it gives rise to another feature called cellularity. It includes the presence or absence of membrane-bound organelles. Therefore, on the basis of this fundamental characteristic, we can classify living organisms into two broad categories of eukaryotes and prokaryotes. • Cellularity: Unicellular organisms are those organisms whose body is made up of a single cell, whereas multicellular organisms are those organisms whose body is made up of many cells. Multicellular organisms use the principle of division of labour to perform specialized functions. This results in a specific body design that distinguishes multicellular organisms from unicellular organisms. • Mode of nutrition: The mode of...