Chapter 17
Forests:Our Lifeline
Here is some important points and answer of chapter 17 Forests: Our Lifeline NCERT science of class 8 which helps students to understand topics of chapter.The answer of textbook question of CHAPTER 17 Forests:Our Lifeline of CLASS 8 SCIENCE NCERT help students to better understand the topics of chapter.
Keynotes of CHAPTER 17 OF CLASS 8 SCIENCE:
a)Canopy:- The branches of tall trees look like a roof over other plants in forest are called canopy.
b)Crown:- Branchy part of a tree above the stem is known as crown.
c)Composers:- Microorganisms who convert dead and waste of plants and animals into humus are called Composers.
d) Deforestation:- Removing or cutting down of forests is called deforestation.
e)Humus:- Dead plants and animals convert into dark colour soil is called Humus.
f) Regeneration:-Growing again plants is called regeneration.
g)Seed Dispersal: Moving of seeds from one to another place by different means like animals,birds and air etc.
h)Soil erosion:-Removing of upper layer of soil through air and water is called soil erosion.
These are the important keynotes of Chapter 17 Forests: Our Lifeline.
Here is the Solution Of textbook CHAPTER 17 FORESTS: Our Lifeline.
Ques1. Explain how animals dwelling in the forest help it grow and regenerate.
Ans.A wide variety of animals help the forest to grow and regenerate in the following ways:-
a) Dropping of the birds and animals waste helps herbs and shrubs to grow during in the rainy season.
b)Decomposers like bacteria and fungi help in the formation of humus that provides nutrients to growing plants.
c)Birds and animals help in the dispersal of seed and fruits.
Ques 2. Explain how forests prevent floods.
Ans. Forest play a very important role in checking soil erosion. The roots of the trees in the forest hold the soil as well as water. Forests act as a natural absorber of rain water as the root system of trees allows rain water to seep into the soil. This rainwater as the logged in the water table. Thus, forests help to prevent floods and maintain a regular supply of water to the water sources.
Ques 3. What are decomposers? Name any two of the. What do they do in the forest?
Ans. Decomposers are organisms that act on dead plants and animals and convert them into dark coloured substance called humus. Bacteria and some fungi act as Decomposers.
They play a key role in releasing the nutrients present in dead plants and animals into the soil.
These nutrients are absorbed by the roots of the other developing plants. Thus, decomposers help in maintaining the nutrients cycle in the ecosystem.
Ques 4. Explain the role of forest in maintaining the balance between oxygen and carbon dioxide in the atmosphere?
Ans. Forest consist of a variety of plants take in carbon dioxide and release oxygen during the process of photosynthesis. The oxygen is taken by animals that in turn release carbon dioxide. In this way, the balance between carbon dioxide and oxygen is maintained in the atmosphere. Thus, forests are known as green lungs.
Ques 5. Explain why there is no waste in a forest.
Ans. Forest include autotrophs, heterotrophs, saprotrophs and decomposers. Autotrophs prepare their own food from nutrients available in the soil,while heterotrophs depend upon autotrophs or other heterogeneous. Saprotrophs act upon dead and decaying matter. When autotrophs and heterotrophs die,decomposers act upon them and form humus. Humus consists of nutrients that are again used up by autotrophs. Thus, there is no waste in a forest.
Ques 6. List five products we get from forests?
Ans. A wide variety of products are obtained from a forest five of them are as follows:-
a)paper
b)honey
c)gum
d)lac
e)fibre
Ques 7. Fill in the blanks:-
a) The insects, butterflies, honeybees and birds help flowering plants in ___________
b)A forest is a purifier of _______ and ______.
c)Herbs from the ________ layer with forest.
d)The decaying leaves and animal drappings in a forest enrich the _________.
Ans.a)pollination
b)air and water
c)lowest
d)soil
Ques 8. Why should we worry about the conditions and issues related to forests far from us?
Ans. Forests inevitable assets of the biosphere, forests check soil erosion, prevent floods and maintain the balance of carbon dioxide and oxygen in the atmosphere, it supports a wide variety of plants, animals and microorganisms . Global issues like global warming, extinction of species and floods depend directly or indirectly upon forests. Hence, we should worry about conditions and issues related to forests far from us.
Ques 9. Explain why there is a need of variety of animals and plants in a forest.
Ans. A variety of plants and animals from different levels of the food chain in the forest ecosystem wild species of plants and animals are generally found in forests, thus a variety of animals and plants are needed to maintain biodiversity in the environment.
Ques 10. In fig. 17.15 the artist has forgotten to put the labels and directions on the arrows. Mark the directions on the arrows and label the diagram using the following labels:- atmosphere,clouds, rain,oxygen , carbon dioxide, plant, trees, animals ,roots, under ground water, water label.
Ans.
Ques 11. Which of the following is not a forest product?
a)Gum
b)Plywood
c)Sealing wax
d)Kerosene
Ans. Kerosene
Ques 12. Which of the following statements is not correct?
i)Forests protect the soil from erosion.
ii)Plants and animals in a forest are not dependent on one another.
iii)Forests influence the climate and water cycle.
iv)Soil helps forests to grow and regenerate.
Ans.ii)Plants and animals in a forest are not dependent on one another.
Ques 13. Micro-organisms act upon the dead plants to produce
i)sand
ii)mushrooms
iii)humus
iv)wood
Ans. iv) Wood
THE SOLUTION OF CHAPTER 17 FORESTS:OUR LIFELINE OF SCIENCE NCERT OF CLASS 7 IS GIVEN ACCORDING TO LATEST SYLLABUS CBSE 2020-2021.
FOR ANY QUERY CONTACT US.
RELATED LINK
Class 6 Science CHAP 2 Solution
Class 8 Science Chap 17 Solution
Comments
Post a Comment
Don't worry,We don't spam.