Where Do Microorganisms Live?

The first form of life to develop on Earth were single-celled microorganisms. These organisms are so small that they are visible only through a microscope. They exist as a single cell or a cluster of cells. Between 1665-1683, two biologists from The Royal Society, Robert Hooke, and Antonie Van Leeuwenhoek discovered the existence of microorganisms. All unicellular organisms like protozoans, bacteria and some algae are included under the category of microorganisms and are largely diverse.

Microorganisms are omnipresent, they are found everywhere. They live in every nook and corner you could possibly imagine. On your seat, under the table, over the roof, even on your body parts, your palms, literally everywhere. They also dwell in extreme weather conditions like the equator, poles, deserts, ice-cold water bodies, hot boilers etc and adapt accordingly.

Let’s have a deeper insight into what these microorganisms are.

Microorganisms And Us – Role Of Microorganisms

Microorganisms play a very integral part of our lives. Some are harmful while some are very beneficial to man. Let us look at some of the microorganisms that are beneficial:

Friendly Microorganisms

Microorganisms are being used for a multitude of purposes. Since ages, it has been used in the production of alcohol. They are also used in the preparation of cakes, bread, and curd. Apart from this, some microbes help clean up the environment, such as bacteria. They are also used for the following applications:

  • Helps break down organic wastes into reusable substances which are harmless.
  • Used in the preparation of medicine
  • To increase the fertility of the soil by nitrogen fixation

Making Of Curd And Bread

The curd is obtained by the action of bacteria on milk. A bacterium named Lactobacillus is present in the milk, which promotes the formation of curd by multiplying itself continuously in milk. Bacteria are involved in the making of:

  • Cheese
  • Pickles
  • Yeast and bacteria are important in the fermentation of dosa and idli batter

Yeast is used extensively in the baking industry to make pastries, cakes etc. They do so by continuously reproducing and as they respire they produce carbon dioxide as a result of which dough increases in size due to bubble formation.

Commercial Use Of Microorganisms

Microorganisms such as yeast are grown on natural sugars to produce alcohol, wine, and vinegar on a large scale. Fermentation is the process of converting sugar into alcohol. Yeasts take part in fermentation.

Medicinal Use Of Microorganism

Microorganisms are the primary source of making antibiotics. Antibiotics are medicines that stop or inhibit the growth of disease-causing microorganisms. Antibiotics are produced by growing many fungi and bacteria and are used to treat numerable diseases. Few antibiotics are:

  • Erythromycin
  • Amoxicillin
  • Streptomycin

In animals, antibiotics are used to check microbial infections. They are used in plants to control diseases as well.


On a large scale, vaccines are manufactured using microorganisms to protect animals and humans from various diseases. Diseases such as smallpox, hepatitis, tuberculosis can be prevented using vaccines.

How does a vaccine work?

Antibodies are produced whenever a disease-carrying microbe enters our body. These antibodies help the body to combat the disease. Later, the body remembers how to fight against that particular disease should it re-enter. These antibodies remain forever in our bodies, and we remain protected from these microbes.

Increasing Soil Fertility

Some bacteria help in nitrogen fixation to enrich the soil and increase soil fertility. These bacteria are called biological nitrogen fixers.

Cleaning The Environment

Microorganisms help in cleaning up the environment. They decompose dead and decaying matter from plants and animals, convert them into simpler substances which are later used up by other plants and animals. Thus, they are used to breakdown harmful substances.

Harmful Microorganisms

While most microorganisms are beneficial, some are very harmful to living organisms. Pathogens are disease-causing microbes. These pathogens cause harm in many ways: either by producing diseases, spoiling food, bringing about degradation in commercial products like leather and clothing etc. Let us know more about their damaging activities

Disease-Causing Microorganisms In Humans

Communicable diseases are the diseases that spread through infected food, water, air or physical contact from an infected person to a healthy person. These may spread through droplets of moisture while sneezed through the air or by consuming contaminated water or food. In some cases, diseases are spread by carriers. Carriers are insects and animals that carry the disease-causing pathogens. Example: Housefly, female Anopheles mosquito carries the parasite of malaria, dengue virus is carried by Female Aedes mosquito.

Some human diseases caused by microorganisms

Name of the disease Pathogen Transmission mode
Tuberculosis Bacteria Air
Chicken Pox Virus Contact/Air
Polio Virus Water/Air
Cholera Bacteria Water/Food
Malaria Protozoa Carrier (Mosquito)

Disease-Causing Microorganisms In Animals

Animals too are affected by the activity of microbes. For example, anthrax is caused by bacteria and it is quite a deadly disease, affecting both human and cattle. Viruses can cause foot and mouth disease.

Disease-Causing Microorganisms In Plants

Pathogenic microorganisms stay very active around plants and affect their normal life cycle, hindering their growth and causing diseases. It affects and reduces the yield of potato, apple, orange, rice, wheat, to name a few. However, they can be controlled using chemicals.

Name of the disease Pathogen Transmission mode
Citrus Canker Bacteria Air
Wheat leaf rust Fungi Seeds/Air
Yellow vein mosaic of Bhindi Virus Insect

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