Maharashtra Board Class 5 EVS Part I Chapter 4 Environmental Balance PDF Download

Environmental Balance

Try This

Ask the elders in your family to take you to a riverside or to a lake or stream.

Make a list of all the living things you see there. If you do not know the names of any of the living things you see, make a note of them describing their shape, colour, sound, shelter, etc. Or, draw their pictures. Count how many types of living things you see.

Now repeat the activity near your house, in the school garden or in a field.

Can You Tell?

(1) In the course of your observations, did you notice any signs of the presence of living things though the living things themselves were not seen? For example, did you notice any partly eaten fruits or shells, fallen feathers, animal tracks, dung, droppings, nests, cocoons, eggs, honeycombs, etc.?

(2) Could you observe any microorganisms?

(3) How many types of living things did you see at the places you visited? Do you think you saw all the kinds of living things that belong there? Did you see the same living things at various places or different ones?

The variety we see in all the living things that belong to a particular area is called the 'biodiversity' of that place.

Can You Tell?

Which one of the places you visited shows greater biodiversity?

To study the biodiversity of a place, scientists make a large number of observations. They make these observations in different conditions such as day and night, in different seasons, etc. They use special devices to make observations of living things that are found at great heights or depths as well as of micro-organisms. Observations of many scientists are brought together and studied again. Only when all such efforts are made over a long period of time can we be sure of the biodiversity of a place.

Teacher's Note

Biodiversity means many different types of living things in one place. In India, a forest near a river has more biodiversity than a desert.

Exam Trick

Remember: Biodiversity = many types of living things. Like a city has many people, a forest has many animals and plants.

Points to Remember

Biodiversity means the variety of living things in a place.
Scientists observe for a long time to count all living things.
Scientists use special tools to see small creatures and creatures very high or very deep.
A river place has more types of living things than a dry place.

The Environment

The surroundings and the conditions in those surroundings which affect the life of the organisms there, are together known as their environment. It includes many components such as sunlight, air, water, soil, plants and animals, etc.

Living and non-living things are dependent on each other. There is a lot of give and take or interaction between them. Environmental Science studies these interactions.

Look at the pictures of the living and non-living things shown below. Discuss the mutual relationships between these various factors of the environment.

Teacher's Note

The environment is everything around us. It includes the sun, air, water, soil, and all living things. They all help each other.

Exam Trick

Remember: Environment = sun + air + water + soil + plants + animals. All work together like a family.

Points to Remember

Environment means all things around us.
Living things need the environment to live.
Non-living things like sun, water, and soil are also part of the environment.
Living and non-living things help each other.
Environmental Science studies how all things work together.

The Food Chain

Look at the pictures below.

A worm eats grass and leaves. A grasshopper eats worms. Birds eat grasshoppers.

Can You Tell?

(1) Who eats birds?

(2) What is the food of plants?

Look at the picture below.

There are several links in this chain. If the links were to separate from each other, could they be called a chain? Even though each link is a complete object, it is joined to the links before and after it. If any link comes loose, the chain is broken.

In the first picture, we see the sun, some plants, a worm, a grasshopper and a sparrow. They are all connected. Each of the components - plants, worm, grasshopper, bird - is food for the next one. That is why we say that they form a chain. Such a chain is called a food chain. Each of these components is a link in a food chain.

Can You Tell?

Look at the pictures. What is the deer's food? What is food for the tiger?

The picture below shows another food chain. You have to guess the missing link in it. Look at the first and third pictures. Think of the connection between them and complete the chain.

Teacher's Note

A food chain shows who eats what. For example, grass is eaten by a goat, and a goat is eaten by a lion. This is a food chain.

Exam Trick

Remember: Food chain = plant → animal → bigger animal. Like this: grass → cow → tiger. It is like a ladder where each level eats the one below.

Points to Remember

A food chain shows what eats what in nature.
Plants are always at the start of a food chain.
Each living thing in the chain is called a link.
If one link breaks, the whole chain breaks.
Different places have different food chains.

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