The initiation for eolving taxonomic systems was provided by Aristotle (384-322 BC). He emphasized that animals can be classified according to their way of living, actions, habits and body parts. He observed insects, fishes, birds and whales. The insect orders like Coleoptera, Diptera were created by him. Due to his contributions, he is considered as the ‘father of biological classification’. For modern taxonomy, the first work was carried out by John Ray (1627 - 1705) of England. His most interesting systematic work ‘Synopsis Methodica Animalium Quadrupedum et Serpentini Generis’ was published in 1693. He divided animals into those with blood and those without blood. He also classified animals based on gills, lungs, claws, teeth and other structures. He provided the first good definition of the species as ‘a reproducing unit’. The great Swedish naturalist Linnaeus (Caroli Linnaei) (1707 - 1778) exerted an important influence on further advancement in taxonomy. Hence he has been called the father of taxonomy. In 1758 he published his famous book, systema naturae.
He first introduced the hierarchic system, both in animal and plant kingdoms. He followed four categories namely class, order, genus, species for the animal world. His greatest contribution to taxonomy was the use of binomial nomenclature for all species of animals and plants. Michael Adamson (1727 - 1806), a French botanist, stressed that classification should be based on as many characters as possible. His concept helped to develop a new type of taxonomy called ‘Numerical Taxonomy’. Lamarck (1744 - 1829) made the first attempt to improve Linnaen system. He published seven volumes of his ‘Histoire Naturelle des Animaux sans Vertebres’. He arranged animals according to evolution. He displayed the groups of animals in the form of a branching tree. It was the beginning of the use of phylogeny in systematics.