Taxonomy (taxis - arrangement, nomos - law, de Candolle, 1813) is defined as the science dealing with identification,nomenclature and classification of organisms. It is the study of rules, principles and practices of classification ,identification and nomenclature of organisms.Taxonomy of plants is also called systematic botany and that of animals is called systematic zoology. Carolus Linnaeus is called the father of taxonomy or father of systematic botany. H. Santapau is called the father of Indian taxonomy.
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Alpha taxonomy (Turill, 1938) considers only morphology.
Beta taxonomy (Turill) considers genetics, anatomy, physiology etc. besides morphology.ω (omega) taxonomy is based on phylogenetic relationships.
Fundamental components of taxonomy
Classification - It is the arrangement of organisms into convenient categories or groups on the basis of their similarities and differences in certain easily observable but fundamental characters.
Identification- It is to determine the exact place or position of an organism in the set plan of classification.
Nomenclature (nomen - name, calare - call)- The process of giving scientific names to plants and animals is called nomenclature.
Different between systematics and taxonomy
Systematics -(Gk.systema-order, sequence) is the science that deals with diversity of organisms and all their comparative and evolutionary relationships based on the study of comparative anatomy, morphology, biochemistry, physiology etc by grouping of organisms at every level of classification. This term is often used interchangeably with taxonomy.
Taxonomy-It It takes into account of external and internal structures, alongwith the structure of cell, development process and ecological information of organisms.It is used in characterisation,identification and nomenclature
Introduction of Nomenclature
Nomenclature is the science of providing distinct and proper names to organisms as per the established universal practices and rules. Every taxonomists has to follow these rules.Binomial nomenclature is a system of classification introduced by Carolus Linnaeus, the 18th century Swedish naturalist, in which each species is given two names.The first is the generic name, written with a capital letter, which designates the genus to which the species belong and the second is the specific name or specific epithet, indicating the species and then the name of the discoverer in full or in abbreviation. Example, Mangiferaindica Linn.
The scientific name is printed in italics. It is underlined in handwritten description.The name of the author is kept in Roman script.The original names were taken from Latin and Greek languages. New names are now derived either from Latinlanguage or are latinised. This is because Latin language is dead and therefore, it will not change in form or spellings with the passage of time.
There are five codes of nomenclature:
ICBN - International Code of Botanical Nomenclature.
ICZN - International Code of Zoological Nomenclature.
ICBacN - International Code of Bacteriological Nomenclature.
ICVN - International Code of Viral Nomenclature
ICNCP - International Code of Nomenclature for Cultivated Plants.
Taxonomical hierarchy
other in descending order, starting from kingdom to species.The hierarchy indicates the various levels of kinship.The number of similar characters of categories decreases from lowest rank to highest rank i.e., from species to kingdom.It includes 7 obligate categories in the following order:To make taxonomic position of some species more precise intermediate categories like sub diviS10n, super order,suborder etc. have been added.Each category, referred to as a unit of classification represents a rank and is commonly termed as a taxon (p.taxa), eg., taxon bryophyta belongs.to category division,taxon Zea mays belongs to category species.
Kingdom-Highest one with least specificity eg., all plants (seeded or seedless, flowering or non
flowering) fall under the plant kingdom.
Phylum-Formed of one or more classes e.g.. phylum chordata (4 classes, e.g, mammalia) and
division spermatophyta (9 classes, e.g, dicotyledonae).
Class-Made of one or more related orders, e.g.. class dicotyledonae, (many orders e.g.
polemoniales); class mammalia (26 orders e.g. carnivora).
Order-Includes one or more related families e.g., class polemoniales has families solanaceae,
polemoniaceae etc., order carnivora includes felidae, canidae, etc.
Family-Contains one or more related genera (sing. genus), having some common features but
some characteristic differences too, e.g, solanaceae includes Solaum, Datura,
Nicotiana, etc., while family felidae includes Felis, Panthera, etc.
Genus-Group of related species which are presumed to have evolved from a common ancestor
but with evolution became unable to interbreed e.g., genus, Solanum has many species
like S. tuberosum, S. melongena, S. nigrum etc.
Species-Group of individuals resembling one another in all morphological and reproductive features which can interbreed freely to produce fertile offsprings.
Taxonomic aids
Techniques, procedures and stored information that are useful in identification and classification of organisms are called taxonomic aids.
THE THREE DOMAINS OF LIFE
Advent of molecular biology led Carl Woese (1977) to introduce three domain system dividing life forms into Archaea, Bacteria and Eukarya.He separated prokaryotes into Archaea (archae ancient,one of the oldest living beings) and bacteria based on thedifferences in their 16S rRNA genes.The three domain system adds a level of classification (the-domains) above the kingdoms present in 5 or 6 kingdom system.
Taxonomic keys
Artificial analytic device having a list of statements which are used for identifying organisms.Usually cach statement called lead has couplet or two Contrasting characters.Two types of keys-bracketed and indented (yolked) areused commonly
Botanical garden
Collections of living plants maintained for reference.Largest botanical garden is in Moscow.Most famous botanical garden is Kew garden.
Museum
Aplace used for storing, preservation and exhibition of objects of natural history, art and objects of natural antiquities.Provides information not only about local flora and fauna but also of other areas.
Herbarium
A collection of plants that usually have been dried, pressed and preserved on sheets.Standard size is 41 cm 29 cm.Largest herbarium of the world is at Kew.
Zoological park
Enclosed areas where animals are kept in open enclosure instead of cages.Helps to study wild animals and food habits.Useful for ex-situ conservation through captive breeding of endangered animals.