Diversity in the Living World


Diversity is simply defined as ‘the variety of life’. It refers to the total number and types of plants and animals present on earth. The total number of species so far identified and described is nearly 1.75 million, and scientists claim that several millions of species are yet to be discovered.

Due to this immense diversity, same animals were given different vernacular names (local names) in different places and countries. It created a lot of confusion in identifying and classifying animals and plants. In order to rectify this ambiguity, scientists decided to give a standard and uniform naming system for all living things present on earth. This system of naming organisms scientifically is known as Nomenclature.


Nomenclature is the process of standardization of names of organisms such that an organism is known by the same name all over the world. The most widely used and accepted system of nature is Binomial Nomenclature. It is the system of naming an organism using two words.

Binomial nomenclature was first introduced by Carolus Linnaeus. He published the book ‘Systema Naturae’. Each name two components- Generic name and Specific epithet (Species name).

For example, ‘Mangifera indica’ is the binomial nomenclature of mango tree and ‘Panthera leo’ is the binomial nomenclature of lion.

The first part of the scientific name i.e. Mangifera and Panthera are the generic names.

It represents the name of the genus of the organism.

The second part, indica and leo are the specific epithets.

It is used to identify a particular species from the other species belonging to the same genus. The generic name and the specific together form the full scientific name for an organism.


Importance of Nomenclature

  1. Clarity in names: Naming an organism scientifically removes the confusion which can arise when we use common names and local names of an organism.
  2. Uniqueness: Scientific naming ensures that an organism is known by the same name all over the world, and hence provides a unique name to each organism.
  3. Widespread use: Since the binomial nomenclature is unique, it can be used by scientists and biologists in various parts of the world. The naming process of plants is based on the principles and criteria of ICBN (International Code for Botanical Nomenclature). Similarly, animals are named on the basis of rules of ICZN (International Code of Zoological Nomenclature).

Universal rules of nomenclature

The basic rules for giving a binomial nomenclature are as follows:

Scientific names are in Latin and printed in italics.

Mangifera indica (Mango)

Homo sapiens (Human)

Oryza sativa (Rice)

Triticum aestivum (Wheat)

If the name does not have a Latin origin, then the word is Latinized.

Eg. A fish species discovered from Chalakkudy River belonging to Sahyadri range of Western Ghats was named as Sahyadria chalakkudiensis

The first word is genus name (Generic name) and second word is the species name (specific epithet).

Mangifera – Generic (genus name)

indica – Specific epithet

Genus name starts with capital letter and species name with small letter.

Mangifera indica

When handwritten, both words of the name should be underlined separately.

Mangifera indica


Author’s name (in abbreviated form) appears at the end of biological name.

Mangifera indica Linn. (Linn. stands for Linnaeus)


It is very difficult to name organisms one by one as there are millions living organisms. Hence, Scientists decided that naming will be easier if the organisms are grouped into convenient categories based on their similarities. This process of grouping organisms into different categories based on easily observable characters is known as classification. The scientific process of classifying living organism is known as taxonomy.

Taxonomy is thus defined as the science of defining groups of biological organisms on the basis of shared characteristics and giving names to those groups. Carolus Linnaeus is regarded as the father of taxonomy. To identify the similarities among organisms, various characteristics like external and internal structure, cell structure, development, ecological information should be evaluated. This description of organisms forms the basis of modern taxonomy.

If the classification not only uses characteristic features, but also the diversities and relationships among different organisms, the process is known as Systematics. The term Systematics is derived from the Latin word ‘systema’ which means systematic arrangement of organisms.


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