Basics of Systematic Study

Early classifications were concerned entirely for easy identification of useful and harmful plants and  animals. Hippocrates and Aristotle arranged animals on the basis of habitat into aquatic, terrestrial, aerial animals. On the basis of single character, Greek scholars divided animals into  four major group- insects on the basis of form, texture and habit into four groups- trees, shrubs, under shrubs and herbs. He described 480 plants in his book ‘Historia Plantarum’

Pliny the Elder introduced the first system of articial classification. His book, Historia Naturalis, mentions over 1000 economic plants with about 2000 items. More and more organisms ere discovered and named. John Ray  English naturalist, described about 18600 plants in there volumes ‘Histroria Generalis Plantarum’ the first time. John Ray defined species as an assemblage of individuals with similar parentage and having ability to pass the parental traits to the offspring. Swedish naturalist Carolus Linnaeus developed the scientific systems of naming species. It is known as binomial systems of nomenclature. Linnaeus described 5900 species of plants in his book  Species Plantarum and 4326 species of animals in systems Naturae.

       Right from Aristotle to Linnaeus, Every systematist employed limited number of traints for classification of organisms. Therefore, the system proposed by them remained artificial. Later on with increased in-depth study of various biological domains, more and more characters were takens into consideration by taxonomists. It brought out natural affinities amongst organisms. This represented the phased of Classical taxonomy which produced natural systems of classification. A modification of this systems is numerical or Phenetics which came into existence during 1950s. Simultaneously biologists began to find out evolutionary and genetic relationships. This resulted in development of phylogenetic classification or cladistics. In cladistics Organisms are arranged in historical order in which they evolved as branches of the parent stock. This phase in known as new systemtics or biosystematics. Father of new systematics is Sir Julian Huxley.

Basics of Systematic Study

1.       Characterisation.  The organism to be studied is described for all its morphological and other characterition.

2.       Identification. Based on the studied characteristics, the identification of the organism is carried out to know whether it is similar to any of the know group or taxa.

3.       Classification. The organism is now classified on the basis of its resemblance to different taxa. It is possible that the organism may not resemble any known taxa or groups. A new groups taxon is  raised to accommodate.

4.       Nomenclature. After placing the organism in various taxa, its correct name is determined If the organism is new to systematics, it is given a new name based on rules and convetions  of nomenclature.

Classical Taxonomy   

  It is taxonomy based on  observable morphological characters with normal individuals considered to be expression of the same while their variations are believed are to be imperfect expressions. Classical taxonomy originated with Plated followed by Aristotle, Theophrastus up to Linnaeus and his contemporaries.

1.       Species are delimited on the basis of morphological characters.

2.       Only A few characters are employed for classification.

3.       A few individuals or their preserved specimens are for study. It is called Topological concept.

4.       Species are believed to be static or immutable.

5.       Species is centre stage of study. Its subunits are important.