Basis Of Biological Classification

Q: Who is considered the Father of Taxonomy and which book was written by him/her?

Carolus Linnaeus is known as Father of Taxonomy and he wrote the book ‘ Systema Naturae'.

May 23, 2023, 16:45 IST

Life on the earth began around 3.7 billion years ago. Earth is home to countless species ranging from microbes to giant whales.

Biological Classification refers to a scientific procedure which involves the arrangement of various organisms in a hierarchical series of groups and sub-groups based on their similarities and dissimilarities.

It is also known as Taxonomy and it is defined as classification of living and extinct creatures on the basis of their scientific standards. Many organisms are yet to be discovered. So we need a system to classify the organism to put them in an organized manner.

Animals and Plants are classified into different categories as follows:

Kingdom → Phylum(for animals) / Division(for animals) → Class → Order → Family → Genus → Species.

Table of Content
History of Biological Classification Levels of Biological Classification Types of Classification System Importance of Biological Classification Biological Classification: FAQs

History of Biological Classification

Aristotle is known as ‘Father of Biological Classification’. He first realized the importance of group names or team names in the study of animals.

He classified organisms based on their habitat i.e. water, air and land.

Following him, scientists began to study the organisms based on their features or traits. Biologists started classifying organisms on the basis of specific characteristics like behavior, appearance, function etc.

Example: a bird can fly but dogs cannot fly so they were placed in different categories.

Later, a Swedish Botanist and naturalist Carolus Linnaeus developed the two part Binomial Taxonomy or classification method to categories living forms on the basis of genus and species. Linnaeus wrote ‘Systema Naturae( The System Of Nature) in 1735 in which he gave a new system of Binomial Classification of plants and animals. In Binomial classification each species is given a particular name based on its genus and species.

Charles Darwin ‘Origin of Species’ provided a solid base for categorization of organisms.

Later, Carolus Linnaeus' work was combined with the work of Charles Darwin to form a foundation of modern taxonomy.

There are some specific features which are used in the classification organisms:

Type of cells based on the presence of nucleus, whether cells are eukaryotic or prokaryotic
Number of cells whether an organism is single- celled or multicellular.
Mode of nutrition i.e. Organism is autotroph (photosynthetic) or Heterotroph ( Non-photosynthetic).
Level of organization and organ development in species.

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Levels of Biological Classification

Organisms are classified and take place in the form of different taxonomic levels.

Domain - It is the highest level of biological classification. The domain can be divided into three types

Archaea B. Eukarya C. Bacteria
Archaea and bacteria are genetically different from each other. Bacteria are also Prokaryotes and they do not have membrane-bound intracellular organelles and nucleus.

Kingdom - It is the second highest level of biological classification. There are five kingdoms i.e. plants, animals, fungi, protists and monerans. Kingdom Animalia is the most diverse kingdom and is divided into vertebrates (animals with a backbone) and invertebrates (animals without backbone).

Kingdom Plantae consists of all plants, flowers, bushes and vegetation. It is the oldest kingdom.
Kingdom Fungi consists of Molds, yeasts, toadstools, mushrooms etc.
Kingdom Protista is the mother of all eukaryotes.
The Monera kingdom consists of archaea and bacteria.

Phylum - Phylum is sometimes termed as ‘division’ in plants and lies after the Kingdom and is classified on the basis of phenetic and phylogenetic. Phonetics is based on a number of shared characteristics and phylogenetics is based on evolution and relationship sharing.
Class - It falls between phylum and order. Each phylum contains multiple classes. Class generally ends with the suffix ‘ae’. A large class can be subdivided into subclasses.
Order - Order is placed above family and below the class. An order can have multiple families.
Family - Family refers to a group of genera with similar characteristics and traits. Family lies between order and genus.
Genus - It is a systematic unit which helps in determining species or an organism.
Species - It has final ranking on the biological classification. Species is a group of organisms with similar characteristics which are able to interbreed with one another. Offspring produced are also capable of creating a new generation as well.

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Species can also evolve into another by the process of Speciation.

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Types of Classification System

Two - Kingdom Classification system

Organism were first classified into only two kingdoms i.e. Animalia and Plantae. Kingdom Plantae includes all Autotrophs which can make their own food by Photosynthesis. Animalia consists of all Heterotrophs which cannot make their own food.

Three - Kingdom Classification System

A new kingdom, Protista, was added by taxonomist Ernst Haeckel. He created this new kingdom to classify species like Euglena. He also put bacteria under this kingdom.

Four - Kingdom Classification System

Fourth Kingdom Monera was added by Copeland in 1938.

Five - Kingdom Classification System

‘Prokaryotic’ term was given for bacteria and ‘Eukaryotic’ term was given for plant and animal cells by E.Chatton. Later, Five kingdom classification was proposed by Robert Whittaker in 1969. He created five kingdoms named Fungi, Protista, Monera, Plantae and Animalia.

Six - Kingdom Classification System

Carl Woese introduced the Six Kingdom Classification System. It divided Monera into Archaebacteria , Eubacteria and other Eukaryotes in the third Kingdom.

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Importance of Biological Classification

Biological Classification is the unique categorisation of different organisms based on different characteristics. Classification provides information about our evolutionary process and how one organism is related to another organism. It provides information of various life forms before us and makes us understand about interrelationship among different organisms and groups. It also provides a better understanding for the development of biological sciences. It is useful in making the study of various organisms easier. It provides a unifying language about organisms which is understood by biologists of all countries.