Biological Classification of Organisms Notes PDF

Classification of Organisms

Here are the short notes of “Living Organism Classification” which will help you in your exams like SSC, Banking, and other competitive examinations.

The scientific way of grouping, identifying, and naming living organisms on the basis of certain characteristics is called “Classification”.

Systems of Classification

There are two ways or systems of classification.

  1. Artificial System- Based on one or a few characteristics of a group. It provides little information.
  2. Natural System- Based on many characteristics. It conveys a lot of information.

Carolus Linnaeus is called the father of Taxonomy.

Taxonomy is the branch of biology that deals with naming and describing of organisms.

Carolus Linnaeus divided all living organisms into 2 kingdoms.

  • Plantae- The Plant Kingdom
  • Animalia– The Animal Kingdom

The chronological order of various units of Classification is – species, genus, family, order, class, phylum, and kingdom.

Whittaker’s Arrangement

Whittaker Arranged Organisms into 5 Kingdoms

  1. Monera
  2. Protista
  3. Fungi
  4. Plantae
  5. Animalia

The arrangement of the organisms was based on the following criteria-

  • Cell Structure of the Organisms.
  • Body Structure.
  • Mode of Nutrition.

Monera- are microscopic, unicellular, and prokaryotic organisms. Ex- bacteria, blue-green algae.

Protista- are unicellular and eukaryotic organisms. Ex- Euglena, Amoeba, etc.

Fungi- are multicellular, eukaryotic, and heterotrophic (non-green plants). Ex- mushrooms etc.

Plantae– are multicellular, eukaryotic, and autotrophic (green plants). Ex- red, brown, and green algae, bryophytes, gymnosperms, etc.

Animalia- multicellular, eukaryotic, and heterotrophic. Ex- All Vertebrates and Invertebrates

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Naming of Organisms

It helps in identifying and differentiating the organisms from each other.

The naming of an organism is called “Nomenclature”.

The current scientific method of naming was given by Carolus Linnaeus.

In binomial nomenclature, the name of an organism is composed of two Latin words-

Genus called a generic name.

It refers to the name of a species called a specific name.


The first letter of the generic name is written in capital letters whereas the first letter of the specific name is written in small letters. Ex- Rana tigrina (Frog)

The scientific names are italicized in printing and underlined while writing.

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