NCERT Question 8 - Chapter 2 Class 8 - Microorganisms : Friend and Foe

Write a short paragraph on the harms caused by microorganisms.

Answer

Microorganisms are harmful in many ways,they can be harmful for plants,animals as well as humans beings.Such disease causing microorganisms are called Pathogens

Disease causing Microorganism in Humans

When a person suffering from cold sneezes,drops of moisture  are spread in air.These drops contain thousands of virus,

When it reaches healthy person,he gets infected

These can also be spread by

Physical contact(Touching an infected person)

Water(Drinking water from same utensil)

Food(Eating food from same utensil)

Disease causing Microorganism in Animals

Some insects and animals carry harmful microorganisms(pathogens) on them

Example

Housefly

They stick on garbage and pathogens sick to body

Mosquito

Female Aedes mosquito acts as carrier of dengue virus

Disease causing Microorganism in Plants

Microorganisms cause disease in plants which reduces the yield of the crop,these can be reduced by using some chemicals which kill the microbes.

Diseases in Plants

Bacteria

Fungi

Virus