Forests: Our Lifeline Class 7 Extra Questions and Answers Science Chapter 17

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Class 7 Science Chapter 17 Extra Questions and Answers Forests: Our Lifeline

Extra Questions for Class 7 Science Chapter 17 Forests: Our Lifeline with Answers Solutions

Forests: Our Lifeline Class 7 Extra Questions Very Short Answer Type

Question 1.
Give four examples of forest animals.
Answer:
Tiger, lion, elephant, bear, etc.

Question 2.
What is meant by canopy?
Answer:
The branches of tall trees look like a roof over the other plants in the forest is called canopy.

Question 3.
Why do trees vary from place to place in their shapes and sizes?
Answer:
Because of different climatic conditions.

Question 4.
Define carnivores.
Answer:
The organisms which eat flesh and are dependent on other animals for food are called carnivores.

Question 5.
Define herbivores.
Answer:
The organisms which depend on plants or plant products for their food are called herbivores.

Question 6.
Give three examples of herbivores.
Answer:
Deer, elephant, rabbit.

Question 7.
How can the presence of an animal be recognised in the forest?
Answer:
By its droppings and footprints.

Question 8.
Define food web.
Answer:
Several interrelated food chains or feeding relationship among organism in an ecosystem is called food web.

Forests: Our Lifeline Class 7 Extra Questions Short Answer Type

Question 1.
Differentiate between autotrophs and heterotrophs.
or
Differentiate between producer and consumer.
Answer:

Autotrophs/Producer	Heterotrophs/Consumer
(i) These are the organisms capable of synthesising their own food.	(i) These are the organisms that depend on other organisms for their food.
(ii) They are producer in an ecosystem.	(ii) They can be consumers, or decomposers.
(iii) For example, green plants.	(iii) For example, all animals and microorganisms.

Question 2.
Give an example of food chain.
Answer:
Grass is eaten by insects, which in turn, is taken by the frog. The frog is consumed by snakes. This is an example of food chain.

Question 3.
Name any four birds which you expect to see in a forest.
Answer:
Kingfisher, blue jay, hornbill and jungle crow.

Question 4.
How does the forests floor look like?
Answer:
The forest floor looks dark-coloured and covered with a layer of dead and decaying fruits, plants, leaves, twigs and small herbs, which is quite moist and warm.

Question 5.
What do you mean by deforestation? Give some causes of deforestation.
Answer:
The excessive cutting of trees for personal or commercial purposes is called deforestation.
Two causes of deforestation are as follows:

Land is required to be cleared for cultivation, construction of houses, road, etc.
Forest fires cause huge loss to forest cover which may be natural or by man.
Overpopulation too directly affects forest covers with the expansion of his habitat.
Felling of trees recklessly for obtaining timber also causes deforestation.

Question 6.
What is the importance of dense bushes and tall grasses for animals living in the forests?
Answer:
The dense bushes and tall grasses provide the animals with food and shelter. Moreover, they protect the herbivores from carnivores living in the forest.

Question 7.
Why is it dark inside a forest?
Answer:
It is dark inside the forest because sun rays are hardly able to penetrate through the dense covering of leaves. The canopy of tall trees form a roof over the other plants. The trees also get covered with different types of creepers and climbers.

Question 8.
How does photosynthesis and respiration maintain the 02-C02 balance in the atmosphere?
Answer:
Photosynthesis is the process in which carbon dioxide gas is used and as a byproduct oxygen is given out. This oxygen is used by the animals for respiration and carbon dioxide is given out which is again used by green plants for photosynthesis.

Question 9.
How do forests help in bringing rain?
Answer:
Trees absorbs water from the soil through their roots, and the excess water is released in the atmosphere through transpiration in the form of water vapour. This released water vapour forms clouds which later bring rainfall.

Question 10.
Why are forests called green lungs?
Answer:
Forests, like lungs, maintain the 02-C02 balance in the atmosphere. Therefore forests are called green lungs.

Forests: Our Lifeline Class 7 Extra Questions Long Answer Type

Question 1.
Write the importance of forests.
or
Why forests are also known as our ‘lifeline’?
Answer:
The major importance of forests are following:

They maintain the 02-C02 balance in the atmosphere.
They maintain ground water level.
They prevent the soil from getting eroded.
They provide us with food, shelter, medicines, timber, wood and other useful products.
They maintain water cycle in the nature.

Question 2.
How does forests sustain a large variety of animals?
Answer:
Different types of animals live in the forest, like herbivores, carnivores, scavengers, etc. Forest provides them with suitable living conditions. The animals get their food in the forest itself. Herbivores feed on plants. Carnivores eat herbivores and thus survive. When these animals die, various scavengers like vultures, eagles, etc., feed on their dead bodies.

Numerous microorganisms also live in the forest that convert dead and decaying plant and animal tissues into humus. They are called decomposers. Thus, they provide a hostile condition for all the animals.

Question 3.
How do forests prevent soil erosion? Explain.
Answer:
The removal of top layer of fertile soil by the action of wind, river or rain is known as soil erosion. This can change a fertile land into a desert. This happens in areas which are not covered with vegetation like trees and plants.

The roots of plants and trees bind the soil particles together firmly. Owing to this, strong winds and flowing rivers find it very difficult to take away the particles of soil. In this way soil erosion is prevented.

When it rains heavily in a forests, the rainwater is first intercepted by the canopy and then it comes down through stem, branches and leaves of the forest plants. Over this process the speed of the rainwater slows down. In this way, the rainwater does not hit the floor of the forest directly. The forest floor covered with fallen, leaves and twigs absorbs water readily and do not allow it to flow and thus, also prevent soil erosion.

Question 4.
As an active citizen, elaborate your role in protecting the forests?
Answer:
At my level I will do the following things to protect the forest:

Use less paper and try to recycle it.
Do not buy any products made up of or obtained from killing of wild animals.
Try to plant as many trees as I can.
Aware people about the importance of forest in our lives.
Reduce use of artificial items as it also create stress on the forest.

Forests: Our Lifeline Class 7 Extra Questions HOTS

Question 1.
How do trees grow in the forest without human interference? Explain.
Answer:
Forest is a self-sustaining system. Forest floor is fertile due to presence of humus. Various agents like animals, wind, water, etc., disperse the seeds of many plants. When these seeds get the favourable conditions, like nutrient, water and proper temperature germinate into a seedling and gradually into a plant. Thus, no human interference is required for trees to grow in a forest.

Question 2.
Explain why a forest is called a ‘dynamic living entity’.
Answer:
Forests are called dynamic living entity because of the various plants, animals and microorganisms. The wide variety of animals helps the forest to regenerate and grow. Decomposers help in maintaining the supply of nutrients to the growing plants in the forest. Thus, in a nutshell forest is a dynamic living entity, full of life and vitality.

Question 3.
How do you think a bunch of seedlings sprouting on a heap of animal dropping in a forest will be benefitted?
Answer:
The decaying animal dropping will provide nutrients to the growing seedlings.

Question 4.
It is a matter of concern if any plants or animals perish from forest. Explain, why?
Answer:
Every component of a forest is dependent on other. If any of these component perish due to any adverse condition all other components of the forest get affected. For example, if herbivores are eliminated from the forest, then the forest will grow very dense due to no one to eat them and the carnivores will perish due to unavailability of food.

Forests: Our Lifeline Class 7 Extra Questions Value Based (VBQs)

Question 1.
Somya likes to buy books and copies. To finish a copy she wastes a lot of space and leave most of the pages blank. When she finds that her book shelf is full with old copies and books she just throw then in the dustbin. Once her cousin Abhishek visited her home. On seeing such a wastage of papers he said to her that this practice of hers is actually the cause of deforestation and she must stop this immediately.
(a) How wasting of papers are the cause of deforestation?
(b) How can we save papers?
(c) What value of Somya is shown here?

Answer:
(a) Papers are obtained from tree fibres. Making of papers causes felling of trees on a large scale. So wasting of papers mean making more papers which cause deforestation.
(b) We can save papers by following ways:

By recycling papers and using recycled papers.
By writing on both sides of papers.
By using all the space available on the paper.
By using paperless technologies like using phone or email to communicate, etc.