Taxonomy - Definition, Classification and Levels

This word taxonomy has its origin in the Greek language. In the ancient Greek language, they were two words – taxis and nomia referring to arrangement and method respectively.

It is that branch of science that deals with the classification of organisms that is called taxonomy.

This classification helps us to easily communicate about organisms. The diversity of life on our planet needs to be understood and organized so this field uses a hierarchical way of classification and organizing.

Alpha taxonomy, evolutionary taxonomy, folk taxonomy etc: are different forms of the subject.

People who are involved in this field are called taxonomists. They generally use observations from behavioral, biochemical, genetic and even morphological traits to a group or arrange the species into a specific classification. However, given the number of life forms, the taxonomic knowledge is still not complete. About 1.7 million species of animals have been named in the past 200 or so years.

Different kinds of animals and plants are called as different “species”. When we say species, we refer to an interbreeding group of organisms that can produce viable next generation which can in turn interbreed. Hence, if we consider a horse and a zebra they cannot interbreed while animals of the same species can interbreed. The taxonomist provides us with unique names for species. It's a label that can help to find more and gain additional knowledge about them. It can sometimes get confusing because if we are discussing, for example, the hedgehog, we need to know if the discussion is about the small spiny insectivore or the orange fungus. All these have the same common name in English. It is for this reason and to provide clarity, the Latin "scientific" name is given as a unique universal identification.

There is a method for naming a species. Specimens are sorted to separate sets which is supposed to be representing a species. Once this first step is done, then they have to see if they already have names. This means reading through descriptions and identification documents generated over the years. They will compare with specimens which seem similar in terms of external characters or sometimes even have to dissect internal structures. In case they don’t find any match, then it could represent a new species, which has not been named before. The taxonomist then will have to write a description, specifying details in which the new species found now can be identified distinctly from others and make up a name in the Latin format. This name and its description must then be formally and properly published so other taxonomists can see what has been done. This process itself can take several years. 
The information from taxonomy is essential for agencies and for the border authorities to manage invasive species from other countries. Effective control can be implemented only if the species is correctly identified. Wrong identification can involve huge money wasted when quick decisions have to be taken. When something is to be eradicated the taxonomist can offer a great level of expertise that is key to developing a very effective yet benign measure of eradication.

The founder of this field is a Swedish botanist named Carl Linnaeus. The system he developed is called Linnaean taxonomy for classifying organisms and a binomial nomenclature for naming organisms.

The basic scheme of modern classification has the following levels:


In the field of biology, biological taxonomy is a sub-discipline of the main subject biology. As taxonomy focusses to describe and organize life, the work done by taxonomists is key for the biodiversity and in the field of conservation biology. In zoology, there is a code regulated by the International Code of Zoological Nomenclature and in the field of botany, it is governed by the International Code of Nomenclature for algae, fungi, and plants.

There are 5 important requirements in the initial description of a taxon 

A – Taxon name must be based on the 26 letters of the Latin alphabet. If it's a new species, then it should be binomial and for other ranks, it should binomial.
B – The name given must be unique and cannot be a homonym.
C – the description given must be based on a minimum one name-bearing type specimen.
D – Should include statements about key relevant attributes to describe the taxon or to identify and differentiate it from other taxa.

Other additional information like geographic range, ecological tips, behavior etc: also, are sometimes included.
Modern-day taxonomy uses database technologies. This helps to search and catalog classifications easily. However, there is no common database. There are some comprehensive ones like “Catalogue of Life” which has attempted to list every documented species.