These AP 7th Class Science Important Questions and 8th Lesson Forests Our Lifeline Class 7 Extra Questions will help students prepare well for the exams.
Class 7 Science Forests Our Lifeline Extra Questions
Forests Our Lifeline Class 7 Important Questions
Question 1.
What do you mean by forest?
Answer:
Forest is a place hosting a number of animals and plants.
Question 2.
Paheli wrote a food chain in the following way:
Frog → Eagle → Insects → Grass → Snake
The chain is not in the correct order. Help her to write the food chain correctly.
Answer:
The correct food chain is:
Grass → Insects → Frog → Snake → Eagle
An insect eats green plant or grass – a frog eats the insects – the frog is eaten by snake – the snake is eaten by an eagle.
Question 3.
Define canopy.
Answer:
The uppermost branches and leaves of tall trees which act as a roof over the forest ground is called canopy. It is the highest layer of vegetation in the forest.
Question 4.
What are producers?
Answer:
Green plants are called procedures.
Question 5.
What is humus?
Answer:
Humus is a dark coloured substance which is formed from the dead bodies of plants and animals.
Question 6.
Define the crown of the tree.
Answer:
The branch part of a tree above the stem is known as the crown of the tree.
Question 7.
What do mean by deforestation?
Answer:
The cutting down and destroying of forests trees for personal as wells for commercial purpose is called deforestation.
Question 8.
What do you mean by afforestation?
Answer:
Planting more trees is called afforestation.
Question 9.
What are the animals lived in the deeper areas of the forest?
Answer:
Animals like boar, bison, jackals, porcupine, elephants live in the deeper areas of the forest.
Question 10.
What are carnivores ?
Answer:
The organisms which eat flesh and are dependent on other animals for food are called carnivores.
Question 11.
Write any three things we get from forests?
Answer:
Gum, medicine and wood are the products we get from forests.
Question 12.
Name some factors responsible for clearing of forests.
Answer:
Construction of roads and buildings, increase in demand for wood industrial development, etc.
Question 13.
What do you mean by food chain? Give an example.
Answer:
The process of food transfer from plants through a series of organisms. The chain of eating and being eating is known as a food chain.
Example : Grașs → Insects → Frog →Snake → Eagle
Question 14.
In which layer of the soil would you find in humus? What is its importance to the soil?
Answer:
Humus are found in the top, organic layer of soil. It provides many useful nutrients to the soil.
Question 15.
Why is the forest’s floor dark in colour?
Answer:
The forest floor is dark in colour because of the decompositions of animal and plant matter into dark-coloured humus.
Forests Our Lifeline Extra Questions
Question 1.
Deforestation may lead to floods. Why?
Answer:
Deforestation leads to floods because as lesser number of trees will be available due to the deforestation. In the absence of trees and plants of the forest, the excessive amount of rainwater falling during heavy rains cannot be absorbed into forest ground. The large amount of rainwater will then suddenly flow into rivers causing the flooding of rivers.
Question 2.
Why are forests called dynamic living entity ?
Answer:
Forests are called a dynamic living entity because everything that resides within it plants or animals are in dynamic equilibrium. The food chain is in continuous function and all that is produced hence is returned to the soil.
Question 3.
How are forests useful to us ?
Answer:
The forests are very useful to us in the following ways :
- They conserve soil and water.
- They are helpful in causing rains.
- They give us food and fruit.
- They are the natural habitats of animals.
- They help in the maintenance of ecological balance.
Question 4.
Define understoreys.
Answer:
The trees in the forest had crown of different types and sizes. These had created different horizontal layer known as understoreys. Giant and the tall trees constituted the top layer followed by shrubs and tall grasses and herbs formed the lowest layer.
Question 5.
Why forests are called as green lungs ?
Answer:
All the green plants absorb carbon dioxide for photosynthesis and release oxygen to the atmosphere. Thus they had to maintain the balance in oxygen and carbon dioxide level in aid. So the forests are called green lungs.
Question 6.
How do forest maintain the water cycle ?
Answer:
The role of forests in the water cycle is to add water to the atmosphere through the process of transpiration (in which plants release water from their leaves during photosynthesis). This moisture contributes to the formation of rain clouds which release the water back onto the forests. This maintains the water cycle and water level in the environment.
Question 7.
How can soil erosion be prevented ?
Answer:
Soil erosion can be prevented by planting more trees, as the roots of trees help to bind the soil and prevent it from being carried away by the rainwater.
Question 8.
Write about the dependence of plants on animals?
Answer:
Dependence of plants on animals :
- Animals produce carbon dioxide during respiration which is released in the atmosphere. Plants use this oxygen for preparing food.
- A number of insects, birds and bats help in pollination.
- Some animals help in dispersal of fruits and seeds.
Question 9.
Plants are known as the producers of a food chain. Give reason.
Answer:
Plants are known as the producers of a food chain. It is because green plants (autotrophs) make their own food from carbon dioxide and water in the presence of sunlight and chlorophyll by a process called photosynthesis and provide food to all living organisms which live in the forest.
Question 10.
What happens if an animal dies in the forest?
Answer:
The dead animals become food for vultures, crows, jackal and insects and in this way nutrients are cycled, thus we say nothing goes waste in forest.
Question 11.
Differentiate between humus and decomposers.
Answer:
Humus is a dark-brown or black organic substance made up of decayed plant or animal matter. Humus provides nutrients for plants and increases the ability of soil to retain water. But decomposers are the microorganisms that convert the dead plants and animals to humus.
Question 12.
How are the nutrients of the soil related to decomposers?
Answer:
Different plants and animals lives in forest. When they die, nobody cremates their dead bodies. They keep on lying there. Scavengers like vultures, eagles etc., eat their dead bodies. They eat flesh and other soft organs. The rest of the dead bodies are broken and down by various microorganisms are called decomposers. They decompose the dead bodies of plants and animals into a dark substance called humus which maintains the nutrient level of the soil.
Extra Questions of Forests Our Lifeline Class 7
Question 1.
What are the various ways we take to conserve our forests?
Answer:
Some of the ways to conserve forests are:
- Excessive cutting down of forest trees should not be allowed by the government to conserve forests.
- More trees should be planted in the forest in place of cut down trees to conserve forests.
- Paper products such as old newspapers, magazines, books, notebooks, etc., should be recycled to conserve forests.
- Awareness programmes should be conducted to educate the public about the importance of afforestation.
- An area should be defined to graze domestic animals so that they don’t damage assets of forest.
- Discourage the use of wooden furniture.
- Impose strict environmental laws.
Question 2.
What will happen if forest disappear?
Answer:
The consequences if forest disappears are as follows :
- Soil erosion will increase which will affect soil fertility and productivity.
- Air pollution will increase which will ultimately threaten thirty existence of life on the Earth.
- Unpredictable changes will take place in weather and climate,
- Reduction in rainfall.
- Reduction in recharging of existing water resources
- Wildlife may also disappear along with forest.
- Shortage of forest products.
- Disturbance in ecological balance.
- Increase in temperature
- Global warming may reach in flooding of low lying area.
Question 3.
Why are forests called the green lungs of a city?
Answer:
Forests are called the ‘green lungs of a city because just like lungs exchange gases, they also do the same. They maintain the balance between carbon dioxide and oxygen in the environment by their dual processes i.e., photosynthesis and respiration. They absorb carbon dioxide from the environment and produce oxygen that we all breathe in. Hence, they are called green lungs.
Question 4.
Write the uses of forests?
Answer:
Forests are useful to us for the following reasons:
- Forests provide timber for building and furniture.
- Forests keep the environment cool and increase the chances of rainfall.
- The roots of the trees hold the soil firmly thereby checking soil erosion.
- Forests provide habitat to a variety of wild plants and animals.
- The plants of forests use CO2 and release oxygen in photosynthesis, thereby maintaining balance of gases in atmosphere.
- Forests provide animal products such as honey, lac, wax, etc.
- Forests provide plant products such as fruits, nuts, gums, resins, fibres, medicines, essential oil (like sandal wood), etc.
- They are involved in the absorption of water which percolates in the soil, thereby becoming a part of the groundwater.
Question 5.
Forests are valuable resources. Explain.
Answer:
Forest products play vital role in socio-economic development. We get food (cereals, pulses and fruits), fire wood, fibre, construction material, industrial products (tannins, lubricants, dyes, resins and perfumes) and products of medicinal importance. It is also the home of diverse wildlife which maintains the ecosystem.
Forests give oxygen to keep us alive and absorb carbon dioxide and it also help in maintaining water cycle in nature. Forests save the soil from erosion and help in maintaining the ground water level.Thus, forests are valuable resources:
Question 6.
All the needs of animals living in a forest are fulfilled. Justify this statement in a few sentences.
Answer:
Forest provides home (shelter), food and water to the animals living there. There are a large number of various types of animals in the forest. The forests provide a natural habitat to animals. The different layers of regulation present in a forest provide food and shelter.
Forest provides leaves, flowers, fruits, seeds, nuts and bark of trees as food for herbivorous animals. The carnivorous animals hunt and eat herbivorous animals. The dense bushes, tall grasses and thick trees provides shelter and also protection for herbivorous animals.
Case Based/Data – Based Questions
Prof. Ahmad asked children to pickup leaves from the forest floor and observe them under a hand lens. They found tiny mushrooms over the decaying leaves. They also saw an army of tiny insects, millipedes, ants and beetle on them. They were wondering how these organisms live there. Prof. Ahmad explained that apart from these animals which are easily seen, there are several organisms and micro-organisms that live in the soil. Paheli wondered what mushroom and other micro-organisms eat. Prof. Ahmad replied that they feed upon the dead plant and animal tissues and convert them into a dark coloured substance called humus.
The micro-organisms which convert the dead plants and animals to humus are known as decomposers. These micro-organisms play an important role in the forest. Soon, Paheli removed some dead leaves and discovered under them a layer of humus on forest floor. The presence of humus ensures that the nutrients of the dead plants and animals are released into the soil. From there, these nutrients are again absorbed by the roots of the living plants. “What happens if an animal dies in the forest?”Sheila asked. Tibu replied the dead animals become food for vultures, crows, jackals and insects.” In this way, the nutrients are cycled. So, nothing goes waste in a forest.
i) Children observed the leaves with the help of.
a) Hand lens
b) Microscope
c) Torch
Answer:
a) Hand lens
ii) The nutrients in the soil are absorbed by which part of the plant?
Answer: The nutrients in the soil are absorbed by the roots.
iii) What are decomposers?
Answer: The organisms which derive their food from the dead and decaying animals or plants are called decomposers.
iv) What did the presence of humus ensures?
Answer: The presence of humus indicates that the nutrients from the dead and decaying organic matter are released in to the soil.