Maharashtra Board Class 5 EVS Part I Chapter 18 The Environment and Us PDF Download

The Environment and Us

Can You Tell?

With the help of the questions below, explain what would happen if forests are cleared on a large scale.

1. Will water and food sources for living things grow or dwindle? Why?

2. Will the living things look for shelters elsewhere or stay on? Why?

3. Will the space occupied by the plants and animals increase or decrease? Why?

4. Will the number of living things increase or decrease? Why?

Deforestation

The population of the world is now close to six hundred crore. Man is developing new technology to meet the needs of all these people, and is using up more and more land and water resources for this purpose.

Open spaces are required on a very large scale for agriculture, housing, industry, and for building roads and railways. Forests are cut down to make place for them.

The environment provides shelter to different kinds of living things. There are many types of plants in forests. Birds build their nests in trees. Animals like the bear, deer, monkey, elephant, tiger all live in the forest, i.e. they find shelter in a forest. All their needs are met in the forest. If forests are reduced, biodiversity is also depleted.

Marshy or low-lying areas are filled to reclaim the land.

Use Your Brain Power!

If a dam is built at a particular place, what changes will be seen in the environment?

Can You Tell?

Time and again, we hear news of certain animals and plants facing the threat of extinction. Reasons for the threats are also given. Collect such news items. Fill in that information in the following chart and display it in your class.

Teacher's Note

When forests are cut down, animals lose their homes and food. For example, when we cut trees in the Western Ghats of India, tigers and leopards have no place to stay and must move to villages, which is dangerous for people.

Exam Trick

Remember: Deforestation = No trees = No animals = Dead environment. Just like a school without a building, how can students study?

Points to Remember

Forests give shelter and food to many animals like bears, deer, tigers, and monkeys.
When forests are cut down, biodiversity decreases.
Deforestation happens because we need space for roads, houses, and farms.
If forests are destroyed, the animals must move to other places or die.

Pollution

You have seen how water sources get polluted if waste water is let into them without processing.

Can You Tell?

(1) What could be the reasons of air pollution?

(2) What are the different purposes for which fuels such as petrol, diesel, kerosene, natural gas, coal and wood are used?

Waste water is also given out from factories into their surroundings. If water from such polluted sources keeps soaking into the soil, the soil becomes infertile.

Chemical fertilizers and pesticides are used on a large scale for agriculture. They seep into the soil or finally flow into rivers with rainwater.

Due to several such reasons water and soil get polluted. This is dangerous for the plants and animals there. Their number reduces and eventually they die out altogether, that is, they become extinct.

Fuel is used in all homes. Besides, there are big industries and factories in which fuel is used in great quantities.

On the one hand, tremendous quantities of carbon dioxide enter the air due to burning of fuels. On the other hand, due to large scale deforestation, the number of trees available for absorbing this carbon dioxide is dwindling. As a result, the proportion of carbon dioxide in the air is rising continuously. When the proportion of carbon dioxide in the air rises, it leads to rise in temperature. We see such a temperature rise in all parts of the world.

Besides, when fuels are burnt in vehicles, they give out certain poisonous gases as well as smoke. Industries also let out some poisonous gases into the air. This leads to air pollution on a very large scale.

Teacher's Note

Pollution happens when we burn fuel in cars and factories. In Indian cities like Delhi, you can see smoke in the sky from cars and factories, which makes the air dirty and bad for our health.

Exam Trick

Remember: Burning fuel = Smoke + Poisonous gases = Air pollution. Just like how a candle makes smoke when it burns, vehicles and factories also make smoke and poison the air.

Points to Remember

Waste water from factories makes rivers and lakes dirty.
Chemical fertilizers and pesticides seep into the soil and pollute it.
Burning of fuel creates carbon dioxide which increases temperature.
Vehicles and factories let out poisonous gases that pollute the air.
Pollution is dangerous for plants and animals.

The Need to Maintain Environmental Balance

Due to human intervention in nature, large scale changes are taking place in the air, water and land. Also, these non-living or abiotic components are getting polluted. As a result, the existence of living things is threatened, while several living things have already become extinct. If one factor of the environment is damaged, its relationships with other factors also get affected, and environmental balance is disturbed. From time to time, some of the living things on the earth become extinct. But today this process is taking place at a much faster rate. This is a threat for the whole living world.

If the different types of plants and animals become extinct one by one, many of the links in the different food chains will be lost. Many scientists believe that this will affect the entire living world on the earth and the balance in nature will collapse.

Do You Know?

You see a food chain in the picture above. One of the links is missing. What effect will it have on the grasshopper? On the bird? What picture should there be in the blank space? If this living thing really died out, what would be the threat to the entire living world? Discuss your answers in the class.

Our Needs and the Environment

Food, water and clothes are the needs of all people. We use a lot of things to meet these needs. Besides, we use many means and devices for the purpose of studies, sport, hobbies and entertainment. We even stock up these things so that they will be available to us whenever we need them. All these things are obtained by using materials from our environment. All the people in the world have similar needs and desires. As a result, the environment is being degraded rapidly.

We need to be aware that we ourselves are a part of nature. If the balance of nature is disturbed, it will adversely affect human beings, too.

We need to take steps to prevent the degradation of the environment. The steps should mainly include using our means frugally and recycling used articles. Such measures should be practised sincerely by each and every person.

Let Us Resolve!

Let us all ensure that no action on our part will cause pollution or cause harm to living things. Let us make all possible efforts for the conservation of the living world.

Teacher's Note

We must use things wisely and reuse old things instead of throwing them away. For example, in Indian homes, people reuse plastic bags and old clothes, which is good for our environment.

Exam Trick

Remember: Save nature = Use less = Recycle more. Just like how your grandmother reused old saris to make new clothes, we should also reuse things to save our environment.

Points to Remember

All people need food, water, and clothes from nature.
We use too many things and throw them away, which harms the environment.
We must use things carefully and not waste them.
Recycling old things helps save the environment.
Every person must help protect nature.

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