What are Microorganisms?

If you are put in an empty room with nobody around and are asked to point at a living being apart from yourself you will probably say “Stop being silly.” Well, think again. There are tiny little organisms all around you, which are so small that it is impossible to see them with your naked eye. These are called microorganisms or microbes. Learn about them using this article on microorganisms for kids.

What exactly is a microbe?

A microbe is the smallest and simplest form of living being, which can be seen only with the aid of a microscope. Microbes come is many different shapes, sizes and varieties. They can work alone or in colonies. For example, an amoeba can live alone in solitary bliss, while fungi help each other survive, by working in colonies. Most importantly, microbes make up the largest number of living organisms on the planet. There are a million upon billion upon trillion microbes around the world. Some of these can make their own food, like plants do and are called autotrophic. Some depend on other living organisms for food like humans and animals do and are called heterotrophic. Microorganisms can reproduce sexually or asexually.

Where do microorganisms live?

No climate is too hot or too cold for microorganisms and no place is too wet or too dry. They can make a home in the North Pole as well as in a geyser. They can live in a rock or in the deepest part of an ocean. Microbes called extremophiles have been isolated from rocks as much as seven kilometres below the Earth’s surface. It has been suggested that the amount of living organisms below the Earth’s surface may be equivalent with the amount of life above the surface. These extremophiles have been known to survive for a prolonged time in a vacuum, and can also be resistant to radiation, which means they also might be able to survive in space. Many types of microorganisms have intimate symbiotic relationships with other larger organisms; some of which are mutually beneficial, while others can be damaging to the host organism. Some microorganisms can cause disease in a host and are known as pathogens.

Microorganisms, our friends

We all love to eat curd, but have you ever thought of how it is made? The answer is microorganisms. The bacterium called lactobacillus reproduces in milk and helps convert milk into curd. Microorganisms are also useful in other food-making processes like brewing, winemaking, baking and pickling. Microorganisms are vital to humans and the environment, as they participate in the Earth’s element cycles such as the carbon cycle and nitrogen cycle, as well as fulfilling other vital roles in virtually all ecosystems, such as recycling other organisms’ dead remains and waste products through decomposition. Microorganisms such as bacteria, decompose organic waste into manure and increase the fertility of the soil. They are also used for making medicines. When you have flu or viral fever and you go to the doctor, you are usually given medicines called antibiotics. These are made with the help of microorganisms. Some bacteria and fungi are used to make these medicines, which kill or stop the growth of disease causing microorganisms. Some vaccines are dead or weakened microbes introduced into the body to produce antibodies. These antibodies protect the body from disease causing microbes. Diseases like polio, cholera, typhoid, small pox, hepatitis etc. can be prevented by taking vaccines. Microbes are also essential tools in biotechnology, biochemistry, genetics, and molecular biology.

Microorganisms to beware of

Just like microorganisms are helpful to human beings and the environment they can also be harmful. Some microorganisms called pathogens cause diseases in plants and animals. There are some microorganisms which grow in food substances and produce toxic substances making the food poisonous, causing illness and even death. There are many microorganisms which you would want to keep out of your house, because they spoil materials like clothing, leather, wood etc. Microorganisms can also be the cause of many infectious diseases. The organisms involved include pathogenic bacteria that causes diseases such as plague, tuberculosis and anthrax; protozoa causing diseases such as malaria and also fungi causing diseases such as ringworm. Disease causing microorganisms called pathogens enter our body through air, water, food, contact or insects. They spread communicable diseases, which can spread from an infected person to a healthy person. Some insects and animals act as carriers of disease causing microbes. For example, a housefly can carry malaria causing microbes, while a mosquito can carry the microbes that cause dengue fever.

Anton Van Leeuwenhoek discovered the first microbe in 1675. Can you find out how he did this?

Looking for more biology articles and videos? Go to: Biology for Kids.