Class 7 Science Forest Our lifeline Important Questions

Very Short Question:

1. Name the resource that serves as green lungs and water purifying systems in nature.
2. What is crown of the tree?
3. Name the process by which plants release oxygen.
4. Name the living organism that helps in maintaining the supply of nutrients to the growing plants in the forest.
5. Name some factors responsible for clearing of forests.
6. Name the plant that forms the lowest layer in forest.
7. What is canopy?
8. Name any two forest products.
9. What is Endemic species?
10. What provides forest for many animals and plants?

Very Short Answers:

1. Answer: Forest
2. Answer: The branchy part of the tree above the stem is known as crown of the tree.
3. Answer: Photosynthesis
4. Answer: Decomposers
5. Answer: Construction of roads and buildings, industrial development, increasing demand of wood etc.
6. Answer: Herbs form the lowest layer in the forest.
7. Answer: Tall trees which look like roof over other plants in the forest is called canopy.
8. Answer: Wax and paper
9. Answer: When an animal or a plant is found in a specific area, it is known as an endemic species.
10. Answer: Home

Short Questions:

1. There is no waste in a forest. Explain
2. Explain how forests prevent floods.
3. What are decomposers? Explain with example.
4. What role does decomposer play in forest?
5. How water pollution will be affected with the depletion of forest?
6. Explain why there is a need of variety of animals and plants in a forest?
7. Why forest floor seemed to be dark coloured?
8. Define the following:

• Crown
• Understoreys

Short Answers:

1. Answer: There are several organisms and micro-organisms that live in the soil convert waste into useful nutrients called humus. This is why there is no waste in forest.
2. Answer: Forest absorbs rainwater and allows it to seep naturally; its leaves and branches prevent rain to hit the ground directly.
3. Answer: The micro-organisms which convert the dead plants and animals to humus are known as decomposers like Fungi and bacteria. They convert dead leaves and dead animals into humus.
4. Answer: Decomposers convert dead leaves and dead animals into humus.
5. Answer: Without tree roots holding the soil in a forest, soil will run into the river and will cause water pollution.
6. Answer: Animals and plants in a forest are dependent on the other for food. So there is a need of variety of animals and plants in a forest. Many food chains can be found in the forest like

Grass→ insects→ frog→ snake→ eagle.

7. Answer: The forest floor seemed dark coloured as it is covered with a layer of dead and decaying matters like leaves, fruits, seeds, twigs and small herbs.
8. Answer:

• Crown: The branchy part of tree above the stem is called crown.
• Understoreys: Trees have crowns of different type and sizes, these creates different horizontal layers in the forest, these are known as understoreys.

Long Questions:

1. Discuss the role of forest in maintaining the balance between oxygen and carbon dioxide in the atmosphere.
2. Explain how animals dwelling in the forest help it grow and regenerate.
3. Explain the importance of forest.

Long Answers:

1. Answer: The forest plays an important role in maintaining the balance between oxygen and carbon dioxide in the atmosphere. As we know plants for their food nutrition requirement make use of process of photosynthesis, in which they consume Carbon Dioxide, released by the living organism from the environment. As a result of photosynthesis, plants release oxygen which is again consumed by living beings for respiration and this cycle goes on.
2. Answer: The wide variety of animals helps the forest to regenerate and grow. In forest, plants produce food. All animals, whether herbivores or carnivores, depend ultimately on plants for food. Organisms which feed on plants often get eaten by other organisms, and so on. For example, grass is eaten by insects, which in turn, is taken by the frog. The frog is consumed by snakes. This is said to form a food chain:

Grass→ insects→ frog→ snake→ eagle.

Many food chains can be found in the forest. All food chains are linked. If anyone food chain is disturbed, it affects other food chains. These food chains produce a lot of supplementary products which are vital for the plants growth. The micro-organisms which convert the dead plants and animals to humus are known as decomposers. Decomposers help in maintaining the supply of nutrients to the growing plants in the forest. Decaying heap of animal dropping is good source of nutrition for plants in the forest. The decaying animal dung also provides nutrients to the seedlings to grow. The animals also disperse the seeds of certain plants and help the forest to grow.

3. Answer: Forests provide us with oxygen. They protect soil and provide habitat to a large number of animals. Forests help in bringing good rainfall in neighbouring areas. They are a source of medicinal plants, timber and many other useful products. By the process of transpiration and photosynthesis, forests maintain the temperature. Forests provide shelter for the animals and act as a protective camouflage. Forests provide shelter and food to the tribes living in the jungle. Forest trees such as the bamboo are used in making furniture, baskets, ladders, etc. The teak tree is used to make furniture. The Neem tree is used for medicinal purposes. Forests also provide wood to make paper and other products such as gum, wax, rubber, and honey. Forests influence the climate, water cycle and air quality. Forests play a very important role in the food chain. When forests are affected, they affect living beings such as animals and plants.