Lesson 3 of 8 · 7 min
Classification, taxonomy and systematics
NCERT §1.1
At the zoo gate, a board sorts the animals: 'Mammals this way, Birds that way, Reptiles house ahead'. Meera's dog would be sent to the mammals. How can one word, 'mammals', tell you so much about an animal you have never seen?
The lesson in notes
In short
Since no one can study every organism one by one, organisms are grouped. Classification is the grouping of things into convenient categories on the basis of easily observable characters.
Each such category is a taxon (plural taxa). 'Plants', 'animals', 'mammals', 'dogs', 'wheat' and 'rice' are all taxa, but at very different levels: dogs are mammals, and mammals are animals.
Naming a taxon calls up its characters at once. Say 'mammals' and you picture animals with external ears and body hair.
Taxonomy is the classification of organisms into taxa based on their characteristics. Modern taxonomy uses external and internal structure, cell structure, the course of development and ecological information.
Characterisation, identification, classification and nomenclature are the four processes basic to taxonomy.
Taxonomy is old. The earliest classifications grouped organisms by their uses to people, for food, clothing and shelter.
Systematics is the study of the kinds and diversity of organisms and of the relationships among them. The word comes from the Latin 'systema', meaning systematic arrangement; Linnaeus titled his publication Systema Naturae.
The scope of systematics was later widened to include identification, nomenclature and classification, and systematics takes evolutionary relationships between organisms into account.