Classification of Organism

Classification of Organism

There are million of organisms. It is important to study each individual separately. Classification means to categories organism into different group.
»   Linnaeus divide all organism into two kingdoms – Plants and Animalia in his book “Systema Nature”. The foundation of modern classification system was laid in the line of classification system started by Linnaeus. Therefore Linnaeus is called 'Father of Thxonomy’. Due to disputed position of organism like bacteria, virus, fungi and euglena, there is a need of reconsideration of system of classification.
»   The book 'Genera plantarium' was written by Benthem and Hooker

Five Kingdom Classification

Five Kingdom Classification was proposed in 1969 by R.H. Whittaker. The criteria of classifying organism into five kingdoms are complexity of cell structure, complexity of body of organism, mode of nutrition, life style and phylogenetic relationship.

1. Monera

It includes all prokaryotic organism like bacteria, cynobacteria and archiobacteria. Filamentous bacteria also come under this kingdom. All organism of this kingdom are microscopic.

2. Protista

This kingdom includes unicellular form usually found in aquatic habitats. On the basis of mode of nutrition they are autotrophic, parasitic, and saprophytic. Diatoms flagellates and protozoa come under this kingdom. Euglena have both heterotrophic and autotrophic mode of nutrition. So, it is placed between plant and animal.

3. Fungi

This kingdom includes nongreen plants. It has saprophytic nutrition and growing on dead and decaying organic matter. The cell-wall is composed of chitin.

4. Planatae

This kingdom includes all plants except algae, diatoms, fungi and member of monera and protista.

5. Animalia

Almost all animal comes under this kingdom except protozoan.

Binomial nomenclature

There was the need of uniform international naming of organism. In biology every organism is given two proper names. The first name is genus name always started with capital letter and the second name is species started with small letter. For example scientific name of human is Homo sapiens. Homo is the name of genus, whose one species is sapiens.

Scientific Names of Some Organisms

Man Homo sapiens Frog Rana tigrina
Mustard Brassica campestris Cat Felis domestica
Dog Canis familaris Housefly Musca domestica
Mango Mangifera indica Rice Oryza sativa
Wheat Triticum aestivum Gram Cicer arietimim
Cow Bosindicus Pea Pisum sativum