Micro-Organisms

We can see several organisms in our surroundings but we can not see some of them with our naked eyes. They can be seen only with the help of a microscope. They are called microorganisms. Some of the microorganisms are shown in Fig-2-6.

Microorganisms are classified into four major groups.

These groups are:

                                     Different shape of Bacteria

                                                            Fangi

                                                            Protozoa

                                                      Algae

                                             Micro Arthropods

Viruses are also microscopic. They, however, reproduce only inside the cells of the host organism, which may be a bacterium, plant or animal. Common ailments like cold, influenza (flu) and most coughs are caused by viruses. Serious diseases like polio and chickenpox are also caused by viruses.

Diseases like dysentery and malaria are caused by protozoans whereas typhoid and tuberculosis (TB) are bacterial diseases. Microorganisms are used for various purposes. They are used in the preparation of curd, bread, and cake. They are also used in cleaning up of the environment. For example, the organic wastes (vegetable peels, remains of animals, feces, etc.) are broken down into harmless and usable substances by bacteria. Recall that bacteria are also used in the preparation of medicines. In agriculture, they are used to increase soil fertility by fixing nitrogen.

Groups of microorganisms

Let us study some micro organisms that belong to the groups like Bacteria, Fungi, Protozoa, Algae and certain micro arthropods with the help of some activities.
For this we need a Microscope. You already know how to use it. You could also refer to “Chapter Cell- Basic unit of life.