Binomial nomenclature

AIPMT-NEET Biology Aspirants, read out the next AIPMT-NEET Biology Study material/ Notes of Binomial nomenclature. In this we will learn about rules of  Binomial nomenclature important for AIPMT-NEET Biology. Free online notes for AIPMT-NEET.

Biodiversity refers to the number and types of organisms present on earth. There is about 1.7 to 1.8 million species in the world, which are known to us and are described.

  • Species are said to be the group of similar or related individuals or organisms that can mate and produce fertile offspring.
  • Species are the fundamental units of systematics and are the basis of classification.
  • New organisms are continuously being identified by researchers and there identification and nomenclature is done to standardize them.
  • Standardization of name of living organisms is necessary so that a particular organism is known by the same name all over the world and there is no confusion created by the local names, which varies from place to place.
  • So, Nomenclature is the process of giving a standard scientific name to the particular organism so that it is known by the same name all over the world.
  • Identification is the process of recognition of essential characters of the organism so the organism is described correctly and nomenclature is done accordingly.
  • For identification and scientific nomenclature of organisms, scientists have established certain rules, principles and criteria, which are acceptable to biologists all over the world.
  • For plants, these rules are set by International Code for Botanical Nomenclature (ICBN). For animals, these rules are provided by International Code of Zoological Nomenclature (ICZN) from 1901. Previously, it is named as International Rules of Zoological Nomenclature.
  • Scientific names ensure that each organism has only one name.
  • Description of any organism should enable the people (in any part of the world) to arrive at the same name.
  • Scientific name ensures that such a name has not been used for any other known organism.


Binomial nomenclature was first used by Swedish naturalist Carl von Linne (Carolus Linnaeus). He listed all the known plants of that time in his book Species Plantarum (1753).

Then in 1758, he published tenth edition of book naming Systema Naturae. In this book (Systema Naturae), he used binomial nomenclature for the first time. In Systema Naturae, Linnaeus listed 4,387 species of animals.

  • Before Linnaeus, Plato and his pupil Aristotle also used the binomial nomenclature, but their work did not get recognized. Linnaeus work was quickly adapted by biologists due to his prestige and influence. That’s why Linnaeus is called as Father of Taxonomy. So, any nomenclature published before 1758, i.e. before work of Linnaeus is not considered valid.
  • Binomial system of nomenclature consists of two components/two words for each name. These two words are Latin words. Two components of name are: Generic name and specific epithet, i.e. genus and species.
  • Latin language is used for nomenclature because it is a dead language and will not change over time.


Universal rules of nomenclature are as follows:

  • Biological names are generally in Latin and written in italics. They are Latinized or derived from Latin irrespective of their origin.
  • First word in a biological name represents the genus while the second component denotes the species.
  • Both the words in a biological name, when handwritten, are separately underlined, or printed in italics to indicate their Latin origin.
  • First word denoting the genus starts with a Capital letter, while that of species starts with a small letter.
  • Name of the author who described the species is also written (with year of publication of name)after the name of species, in complete official format.  It is written in an abbreviated form.
  • If a species described in a given genus later gets transferred to another genus, then name of the author of the original species, is enclosed in parentheses.


Let’s take up an example of mango: The scientific name of mango is written as Mangifera indica.

  • In this Mangifera represents the genus while indica, is a particular species, or a specific epithet.
  • Written in italics as it is printed.
  • Genus starts with Capital letter and species with small letter.
  • Mangifera indica Linn. It indicates that this species was first described by Linnaeus.
  • Mountain Lion: binomial nomenclature is Puma concolor (Linnaeus) indicates that Linnaeus originally classified and named this species. He classified it in the genus Felis, but it was later reclassified in the genus Puma.


NOTE: Recently 4 new frog species are discovered in India from Western Ghats (UNESCO World Heritage site & one of the biggest biodiversity hotspot) by Indian scientist “SD Biju (Frogman of India)” and team. These species are listed as smallest known frogs in the world, ranging between 12.2- 15.4 mm.

  • Trinomial Nomenclature: includes 3 components in name. Genus, species and sub-species. Cabbage is Brassica oleracea var. capitata.
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