9th Class Science Diversity in Living Organisms Classification of Organisms

         Classification of Organisms

Since there is one or the other similarity and dissimilarity among the organisms and. also there are large number of organisms in this world and it is very difficult to identify and understand each of them separately. Hence we need to classify the organisms. The main advantage of classification of organism is that it makes the study of large variety of organism easier. It also tells us the interrelationship among the various organisms. In ancient times the classification was based on some basic criteria such as size, colour, and nature of the organism. Later on the system of classification was based on overall similarities and dissimilarities between the organisms.

In present time the organisms has been classified into two groups as plant Kingdom and animal kingdom. The main difference between plant kingdom and animal kingdom is that plant can manufacture their own food using sunlight and carbon dioxide, where as the animals derive its food from the plants. Later on it was found that there were some organism which fit into neither plants nor animals category. Hence the classification system was further modified.

At present time there are five kingdom of classification:

• Monera
• Protista
• Fungi
• Plant
• Animal

           Hierarchy of Classification

The five kingdom of classification given by Whittaker was based on the cell structure of the organism, mode of nutrition and their body design. The classification is done by naming the subgroups at various level as:

\[\to \] Kingdom Phylum \[\to \] Class \[\to \] Order \[\to \] Family \[\to \] Genus \[\to \] Species

In broadest mode of classification the organisms has been classified into two categories as plant kingdom and animal kingdom. The next step is the phylum which includes all the organism having few common characters. The next is  the mammals. Mammal is followed by order which includes the organism having few common character and are less similar, such as carnivorous and omnivorous. The next step is the family which includes the group having more similarity to each other, such as, the family of cat and lion is similar. The next is genus, which includes the organisms having similar reproductive organs, such as, plants producing flower and fruits. The last step is the species which include the group of organism having same structure and forms, but not necessarily the function and are able to breed among themselves and produce the fertile offspring of their own kind.