Taxonomic systems

Aristotle - (384-322 BC)

The initiation for evolving 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’.

(Caroli Linnaei) (1707 - 1778)

The great Swedish naturalist Linnaeus (Caroli Linnaei)(1707 – 1778) exerted an important influence on further advancement in taxonomy. Hence he has been called thefather 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 allspecies 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.

Cuvier (1769 – 1832) insisted that extinct fossil forms should be included in the table of classification. He divided animals into four branches. They are Vertebrata-fishes to mammals, Mollusca-mollusca and barnacles, Articulata-annelids, crustaceans, insects and spiders and Radiata-echinoderms, nematodes and coelenterates.

The development of modern taxonomy started during 1930s. During this period taxonomy was based on population studies . E. Mayr (1942) considered species as “groups of interbreeding natural populations”. His book ‘New Systematics’ became a landmark in the history of taxonomy. The taxonomists were forced to accept species as a ‘population’. Hence the taxonomist started moving from the laboratory to the field. Morphological characters were studied along with other characters as behaviour, sound, ecology, genetics, zoogeography, physiology and biochemistry. Thus taxonomy was transformed into ‘biological taxonomy’.

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