Natural vegetation: NBSE class 9 social science chapter 8 notes

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Here are the solutions, questions, answers, and notes of chapter 8: Natural vegetation which is a part of social science class 9 syllabus of students studying under the Nagaland Board of School Education. However, these notes should be used only for references and additions/modifications should be made as per the requirements.

Introduction

The earth is a unique planet among all the planets. It is the only planet where life exists. The narrow zone where a variety of organisms exist on the planet is known as the biosphere. This chapter deals with natural vegetation, which is a form of life and means plants or trees that grow on their own without any form of human intervention.

Life on earth would be impossible without trees. They provide us with food, fuel etc. Plants and trees come in various shapes and sizes. Plants range from microscopic green plankton in the sea to gigantic coniferous trees so tall we cannot see their tops. Not every type of plants and trees grow in every part of the planet. What type of plant and trees grow in a particular area depends on the soil, relief, and drainage. Plants of a particular region or period are called flora.

In this chapter, you will learn in details about the different trees and plants and where it grows as well as what conditions are required for the growth.

Textual questions and answers

Choose the correct answer

1. The Bakarwal and Gujjar tribes graze their flock of sheep in:

(a) Tropical rainforests
(b) Tropical thorn forests and scrubs
(c) Temperate forests with grasslands
(d) None of the above

Answer: c. Temperate forests with grasslands

2. Given the commercially valuable trees in the forests, how can sustainable resource management practices be applied to ensure their long-term availability?

(a) Clear-cutting large sections of the forests at once
(b) Banning the harvest of all commercial tree species
(c) Implementing selective logging and reforestation programmes
(d) Encouraging unregulated logging to boost the economy

Answer: c. Implementing selective logging and reforestation programmes

3. Which are the most widespread forests in India?

(a) Tropical rainforests
(b) Tropical deciduous forests
(c) Tropical thorn forests
(d) Alpine and Tundra grasslands

Answer: b. Tropical deciduous forests

4. How many biosphere reserves are there in India?

(a) 14
(b) 15
(c) 16
(d) 18

Answer: d. 18

5. Sundarbans Bioreserve is located in which state?

(a) Assam
(b) West Bengal
(c) Meghalaya
(d) Tamil Nadu

Answer: b. West Bengal

6. There are two statements marked as Assertion (A) and Reason (R). Mark your answer as per the codes provided below.

Assertion (A): The Alpine grasslands are most frequented by Gujjars and Bakarwals who bring their sheep to graze here.
Reason (R): As one goes even higher, Tundra vegetation also includes lichens and mosses.

(a) Both (A) and (R) are true and (R) is the correct explanation of (A)
(b) Both (A) and (R) are true but (R) is not the correct explanation of (A)
(c) (A) is correct but (R) is wrong
(d) (A) is wrong but (R) is correct

Answer: b. Both (A) and (R) are true but (R) is not the correct explanation of (A)

7. Consider the statements given below and choose the correct answer.

Statement I: Afforestation is the best means to conserve forests.
Statement II: Overgrazing leads to destruction of forests.

(a) Statement (I) is correct and (II) is incorrect
(b) Statement (I) is incorrect and (II) correct
(c) Both (I) and (II) and incorrect
(d) Both (I) and (II) are correct

Answer: d. Both (I) and (II) are correct

Very short answer type questions

1. Define flora.

Answer: Plant life in general especially plants of a certain region, environment or period is called flora.

2. What is an ecosystem?

Answer: An ecosystem is a complex set of relationships among the living resources, habitats and residents of an area. It includes plants, trees, animals, fish, birds, microorganisms, water, soil, and people.

3. What is meant by ‘natural vegetation’?

Answer: Natural vegetation means any plants or trees that grow on their own or without any form of human intervention.

4. Which three factors determine vegetation types?

Answer: Three factors that determine vegetation types are temperature, heat, and precipitation.

5. Where are tropical rainforests found?

Answer: Tropical rainforests are found in the Western Ghats, the island groups of Lakshadweep, and the Andaman and Nicobar Island.

Short answer type questions

1. Write a brief note on thorn forests and scrubs.

Answer: Thorny trees and bushes comprise the thorn forests and scrubs of India. These forests are found mainly in the north-western part of India, in regions of less than 70 cm of rainfall, i.e. semi-arid areas of Gujarat, semi-arid areas of Rajasthan, semi-arid areas of Madhya Pradesh, Chhattisgarh, Uttar Pradesh, and Haryana. The main plant species of these forests are Cacti, Acacia, Palms, and Euphorbias.

2. What are tropical rainforests?

Answer: Tropical rainforests are only found in the rainy parts of India, i.e., the Western Ghats and the island groups of Lakshadweep, and the Andaman and Nicobar Island. These types of forests grow bushy in areas that receive more than 200 cm of rainfall and experience a short dry season. In these forests, trees grow to the height of up to 60 meters or even above. Ebony, mahogany, rubber, rosewood, and cinchona are some of the commercially important trees of this forest.

3. What are the characteristics of moist deciduous forests?

Answer: These forests are located in areas that receive 200 cm to 100 cm rainfall. The main locations of these forests are eastern slopes of Western Ghats, West Odisha, Chhattisgarh, Jharkhand, North Eastern states and the Himalayan Foothills. Teak is the most important species of these forests. Other commercially important species are khair, shisham, sal, bamboo, kusum, arjun, mulberry, and sandalwood..

4. What are the features of dry deciduous forests?

Answer: These forests are located in areas that receive 100 cm to 70 cm rainfall. Most of these forests are in the rainier parts of the peninsular plateau, plains of Bihar, and plains of Uttar Pradesh. These forests have open stretches of teak, sal, peepal, neem, etc.

Long answer type questions

1. Why have biosphere reserves been set up?

Answer: Biosphere reserves have been set up because of the following reasons:

I. Conserving and maintaining diversity and integrity of the natural heritage in its full form, i.e., physical environment, the flora, and the fauna.

II. Promoting researches on ecological conservation and other aspects of environmental preservation.

III. Providing facilities for education, awareness and training.

IV. Last but not least, to preserve the genetic variety in the crucial natural ecosystem settings.

2. What is the difference between Alpine and Tundra vegetation and temperate forest with grasslands?

Answer: Temperate forests and grasslands gradually decrease at 3600 metres height. At 3600 metres, above sea level the Alpine vegetation flourishes. The growth of trees becomes stunted as they near the snowline. Alpine vegetation mainly includes birches, pines, junipers, and silver fir.

On the other hand, tropical deciduous forests are found in the Himalayan foothills. Then comes the wet temperate type of forests at a height of 1000 to 2000 metres. Temperate forests at the height of 1500 to 3000 metres are full of coniferous trees that include cedar, spruce, pine, deodar, and silver fir.

3. Explain the ways to conserve forests.

Answer: The ways in which forests can be conserved are:

a. We should plant more trees, i.e., afforestation. All communities should be made aware of the importance of forests. This will prevent the reckless cutting of trees.

b. People living near forests should be made aware of the danger of forest fires and how they cause depletion of forest resources.

c. New cities have led to the destruction of forest areas. Therefore, urban growth should be properly planned so that the minimum area under forests is maintained.

d. Overgrazing by animals leads to the destruction of forests. There should be restrictions and control on grazing by domestic animals.

4. Explain the characteristic features of Tropical Evergreen forests.

Answer: The characteristics of tropical evergreen forests are:

I. Tropical rainforests are only found in the rainy parts of India, i.e., the Western Ghats and the island groups of Lakshadweep, and the Andaman and Nicobar Islands.

II. These types of forests grow bushy in areas that receive more than 200 cm of rainfall and experience a short dry season.

III. In these forests, trees grow to the height of up to 60 metres or even above.

IV. As the region is warm and wet throughout the year a variety of lush green vegetation is abundant here.

V. There is no particular time for the trees to shed their leaves so these forests are green in appearance the whole year.

VI. Ebony, mahogany, rubber, rosewood, and cinchona are some of the commercially important trees of this forest.

Extra MCQs

1. What is the term for the plant life of a particular region or period, considered as a group?

A. Fauna
B. Ecosystem
C. Flora
D. Biosphere

Answer: C. Flora

2. Which of the following drugs is derived from the foxglove plant?

A. Morphine
B. Digitalis
C. Cinchona
D. Quinine

Answer: B. Digitalis

3. Tropical Deciduous Forests are also known by which other name?

A. Evergreen Forests
B. Monsoon Forests
C. Thorn Forests
D. Alpine Forests

Answer: B. Monsoon Forests

4. In which of the following regions are Tropical Rainforests found?

A. Plains of Uttar Pradesh
B. The Himalayan Foothills
C. Semi-arid areas of Gujarat
D. The Western Ghats

Answer: D. The Western Ghats

5. What is the approximate annual rainfall in regions with Tropical Thorn Forests and Scrubs?

A. More than 200 cm
B. Between 100 cm and 200 cm
C. Between 70 cm and 100 cm
D. Less than 70 cm

Answer: D. Less than 70 cm

6. Teak is the most prominent tree species in which type of forest?

A. Dry Deciduous Forests
B. Tropical Evergreen Forests
C. Moist Deciduous Forests
D. Temperate Forests

Answer: C. Moist Deciduous Forests

7. At what altitude do temperate forests and grasslands typically give way to alpine vegetation?

A. Above 1000 metres
B. Above 2000 metres
C. Above 3600 metres
D. Above 5000 metres

Answer: C. Above 3600 metres

8. Which of the following are common trees found in temperate forests at an altitude of 1500 to 3000 metres?

A. Ebony and Mahogany
B. Neem and Peepal
C. Cacti and Acacias
D. Cedar and Pine

Answer: D. Cedar and Pine

9. The nomadic tribes of Bakarwals and Gujjars are most frequently found grazing their flocks in which vegetation zone?

A. Tropical Rainforests
B. Alpine Grasslands
C. Thorn Forests
D. Coastal Regions

Answer: B. Alpine Grasslands

10. Which of the following is NOT a primary aim of setting up biosphere reserves?

A. Promoting ecological research
B. Conserving biodiversity
C. Encouraging urban development
D. Preserving genetic variety

Answer: C. Encouraging urban development

11. How many biosphere reserves have been established in the country to protect flora and fauna?

A. 12
B. 15
C. 18
D. 21

Answer: C. 18

12. The Sundarbans Biosphere Reserve is located in which state?

A. Odisha
B. West Bengal
C. Assam
D. Meghalaya

Answer: B. West Bengal

13. Which of the following medicinal plants is described as an antibiotic and antibacterial?

A. Arjun
B. Babool
C. Kachnar
D. Neem

Answer: D. Neem

14. What is the term for a plant community that has grown naturally without human aid and has been left undisturbed for a long time?

A. Orchard vegetation
B. Cultivated vegetation
C. Virgin vegetation
D. Fauna community

Answer: C. Virgin vegetation

15. Trees like ebony, mahogany, and rosewood are commercially important species of which forest type?

A. Tropical Deciduous Forests
B. Tropical Evergreen Forests
C. Temperate Forests
D. Thorn Forests

Answer: B. Tropical Evergreen Forests

16. Statement I: Trees in tropical rainforests have very broad leaves.
Statement II: The broad leaves help in the transpiration of surplus moisture.

A. Statement I is false, but Statement II is true.
B. Both statements are true, and II is the correct explanation for I.
C. Both statements are true, but II is not the correct explanation for I.
D. Statement I is true, but Statement II is false.

Answer: B. Both statements are true, and II is the correct explanation for I.

17. Statement I: The tropical deciduous forest never appears completely barren at any time of the year.
Statement II: Every species of tree in this forest has its own time for shedding leaves.

A. I is the result of II.
B. II is the result of I.
C. I and II are independent statements.
D. I is a contradiction of II.

Answer: A. I is the result of II.

18. Statement I: Commercial exploitation of a single tree species is difficult in tropical evergreen forests.
Statement II: These forests have a large number of species found together in one area.

A. I is independent of II.
B. I is a contradiction of II.
C. II is the cause for I.
D. I is the cause for II.

Answer: C. II is the cause for I.

19. Statement I: Plants in thorn forests have long, penetrating roots that spread out.
Statement II: The stems of these plants are succulent to conserve water.

A. Both statements describe adaptations to a dry climate.
B. Statement I contradicts Statement II.
C. Statement II is the only correct statement.
D. Statement I is the cause of Statement II.

Answer: A. Both statements describe adaptations to a dry climate.

20. Statement I: As one moves to higher altitudes in the mountains, the vegetation changes.
Statement II: Decreasing temperature with increasing altitude influences the type of plants that can grow.

A. I is an example of II.
B. I is a contradiction of II.
C. II is the cause of I.
D. I and II are unrelated.

Answer: C. II is the cause of I.

21. Statement I: Afforestation is a key method for conserving forests.
Statement II: Overgrazing by domestic animals leads to the destruction of forests.

A. Statement I is true, and Statement II is false.
B. Statement I is false, and Statement II is true.
C. Both statements are true and related to forest conservation.
D. Both statements are false.

Answer: C. Both statements are true and related to forest conservation.

22. (I) The word ‘conservation’ means to preserve and keep together.
(II) It is derived from the Latin words ‘con’ (together) and ‘servare’ (to preserve).

A. I is a contradiction of II.
B. I is independent of II.
C. II is an explanation for I.
D. I is an example of II.

Answer: C. II is an explanation for I.

23. (I) Cultivated crops and fruit orchards are a part of natural vegetation.
(II) Natural vegetation grows without any form of human intervention.

A. I is the cause for II.
B. I is an example of II.
C. I is a contradiction of II.
D. I is independent of II.

Answer: C. I is a contradiction of II.

24. Arrange the following vegetation types in the order one would encounter them while ascending the Himalayas.
(i) Alpine grasslands
(ii) Wet temperate forests
(iii) Tropical deciduous forests
(iv) Tundra vegetation

A. (iii) → (ii) → (i) → (iv)
B. (ii) → (iii) → (iv) → (i)
C. (iii) → (i) → (ii) → (iv)
D. (i) → (iv) → (iii) → (ii)

Answer: A. (iii) → (ii) → (i) → (iv)

25. Arrange the following forest types in descending order of their average annual rainfall requirement.
(i) Tropical Deciduous Forests
(ii) Tropical Thorn Forests
(iii) Tropical Rainforests

A. (ii) → (i) → (iii)
B. (iii) → (i) → (ii)
C. (i) → (iii) → (ii)
D. (iii) → (ii) → (i)

Answer: B. (iii) → (i) → (ii)

26. Consider the succession of vegetation as one moves towards the snowline. Arrange the following in the correct sequence.
(i) Stunted trees
(ii) Alpine grasslands
(iii) Shrubs and scrubs

A. (i) → (iii) → (ii)
B. (iii) → (ii) → (i)
C. (ii) → (i) → (iii)
D. (i) → (ii) → (iii)

Answer: A. (i) → (iii) → (ii)

Extra questions and answers

1. Name the three non-climatic factors that affect vegetation.

Answer: The three non-climatic factors that affect vegetation are soil, relief, and drainage.

2. What is the term for plants of a particular region or period?

Answer: Plants of a particular region or period are called flora.

3. What is the term for the species of animal life in an area?

Answer: Fauna is the term used for the species of animal life of an area.

4. What is another name for natural vegetation that has been left undisturbed?

Answer: Natural vegetation that has been left undisturbed by humans for a long time is also called virgin vegetation.

5. What are the main climatic factors that determine vegetation types?

Answer: The main climatic factors that determine which plant species can flourish are temperature or heat, and precipitation.

6. Name the five major types of vegetation prevalent in India.

Answer: The five major types of vegetation prevalent in India are:

(i) Tropical Rainforests
(ii) Tropical Deciduous Forests
(iii) Tropical Thorn Forests and Scrubs
(iv) Temperate Forests with Grasslands
(v) Alpine and Tundra Grasslands

7. Where are Tropical Rainforests found in India?

Answer: Tropical rainforests are found in the rainy parts of India, which are the Western Ghats and the island groups of Lakshadweep, and the Andaman and Nicobar Islands.

8. To what height do trees in evergreen forests grow?

Answer: In evergreen forests, trees grow to a height of up to 60 metres or even above.

9. Name four commercially important trees of Tropical Evergreen forests.

Answer: Four commercially important trees of Tropical Evergreen forests are ebony, mahogany, rubber, and rosewood.

10. What is the other name for Tropical Deciduous forests?

Answer: The other name for Tropical Deciduous forests is monsoon forests.

11. What is the rainfall range for Tropical Deciduous forests?

Answer: Tropical Deciduous forests are spread over regions that get rainfall between 70 cm and 200 cm.

12. For how long do trees in monsoon forests shed their leaves?

Answer: The trees of monsoon forests shed their leaves for about six to eight weeks in summer.

13. What are the two types of tropical deciduous forests?

Answer: The two types of tropical deciduous forests are Moist deciduous forests and Dry deciduous forests.

14. What is the rainfall range for Moist Deciduous forests?

Answer: Moist Deciduous forests are located in areas that receive rainfall from 200 cm to 100 cm.

15. Name the most prominent tree species of Moist Deciduous forests.

Answer: Teak is the most important and prominent species of Moist Deciduous forests.

16. Name four commercially important species of Moist Deciduous forests.

Answer: Four commercially important species of Moist Deciduous forests are khair, shisham, sal, and bamboo.

17. What is the rainfall range for Dry Deciduous forests?

Answer: Dry Deciduous forests are located in areas that receive rainfall from 100 cm to 70 cm.

18. What is the rainfall requirement for Thorn Forests and Scrubs?

Answer: Thorn Forests and Scrubs are found in regions with less than 70 cm of rainfall.

19. Name four main plant species found in thorn forests.

Answer: Four main plant species found in thorn forests are Cacti, Acacias, Palms, and Euphorbias.

20. How are the stems of trees in thorn forests adapted to the climate?

Answer: The stems of trees in thorn forests are succulent to conserve water.

21. How are the leaves of trees in thorn forests adapted to the climate?

Answer: The leaves of trees in thorn forests are thick and tiny in order to have minimum evaporation.

22. At what altitude are wet temperate forests found?

Answer: Wet temperate forests are found at a height of 1000 to 2000 metres.

23. Name four coniferous trees found in temperate forests.

Answer: Four coniferous trees found in temperate forests are Cedar, Spruce, Pine, and Silver fir.

24. At what altitude does Alpine vegetation begin to flourish?

Answer: Alpine vegetation flourishes at 3600 metres above sea level.

25. Which nomadic tribes frequent the Alpine grasslands?

Answer: The nomadic tribes that frequent the Alpine grasslands are the Bakarwals and the Gujjars, who bring their flocks of sheep to graze there.

26. What does Tundra vegetation include at very high altitudes?

Answer: At very high altitudes, Tundra vegetation includes lichens and mosses.

27. What is the literal meaning of the word ‘conserve’?

Answer: The word ‘conserve’ is coined from the two Latin words ‘con’, which means together, and ‘servare’, which means to preserve. Hence, conservation means to preserve and keep together.

28. What is afforestation?

Answer: Afforestation means to plant more trees.

29. Name two medicinal plants and their specific uses.

Answer: Two medicinal plants and their specific uses are:

Arjun: Its fresh juice cures earache and is good for blood pressure problems and heart diseases.
Tulsi plant: It cures cough and cold.

30. What is the purpose of creating Eco-sensitive Zones?

Answer: Eco-sensitive Zones are created to protect and conserve fragile habitats from human encroachment.

31. Name two areas in India protected by specific acts.

Answer: Two areas in India protected by specific acts are the No Development Zone at Numaligarh East of Kaziranga and the Doon Valley.

32. Name two projects introduced to protect endangered animal species.

Answer: Two projects introduced to protect endangered animal species are Project tiger and project rhino.

33. How many national parks and wildlife sanctuaries have been established in India?

Answer: In India, 103 national parks and 563 wildlife sanctuaries have been established.

34. Why is life on Earth considered impossible without plants?

Answer: Life on earth could not exist without plants. Trees provide us with wood for fuel, furniture and tools. Scientists use plants to make drugs such as digitalis (from foxglove), and morphine (from poppies).

35. What is an ecosystem? What are its main components?

Answer: An ecosystem is a complex set of relationships among the living resources, habitats and residents of an area. Its main components include plants, trees, animals, fish, birds, micro-organisms, water, soil and people.

36. How is ‘natural vegetation’ different from cultivated crops and orchards?

Answer: Natural vegetation means any plants or trees that grow on their own or without any form of human intervention. It refers to a plant community which has grown naturally without human aid and has been left undisturbed by humans for a long time. Thus, cultivated crops and fruits and orchards form part of vegetation but not natural vegetation.

37. What are the climatic conditions required for Tropical Evergreen forests to thrive?

Answer: Tropical Evergreen forests grow in areas that receive more than 200 cm of rainfall and experience a short dry season. The region is warm and wet throughout the year, which allows a variety of lush green vegetation to be abundant.

38. Why do Tropical Evergreen forests appear green throughout the year?

Answer: There is no particular time for the trees in Tropical Evergreen forests to shed their leaves, so these forests are green in appearance the whole year around.

39. Why does the rich biodiversity of tropical rainforests pose a problem for commercial use?

Answer: The tropical rainforests have a unique characteristic of having a large number of species found together. This poses a problem as no particular variety can be targeted for commercial use.

40. Describe the key features of Tropical Deciduous forests.

Answer: The Tropical Deciduous forests are the most widespread forests in India and are also known as monsoon forests. They are spread over a region that gets rainfall between 70 cm and 200 cm. For about six to eight weeks in summer, the trees of monsoon forests shed their leaves. The trees, like neem and mango, have widespread out branches, and their leaves are smaller than those of the rainforests to reduce transpiration. The trees also have less height than evergreen trees and are prized for their hardwood, as commercially valuable timber is collected from these forests.

41. How do the trees in Tropical Deciduous forests differ from those in rainforests?

Answer: In Tropical Deciduous forests, the leaves are smaller in size than that of the rainforests to reduce transpiration. The trees also have less height than evergreen trees.

42. Where are Moist Deciduous forests located in India? Name some important trees found there.

Answer: Moist Deciduous forests are located on the Eastern slopes of the Western Ghats, West Odisha, Chhattisgarh, Jharkhand, North Eastern States, and the Himalayan Foothills. Teak is the most important and prominent species of these forests. Other commercially important species are khair, shisham, sal, bamboo, kusum, arjun, mulberry and sandalwood.

43. Where are Dry Deciduous forests found? What has this region been cleared for?

Answer: Dry Deciduous forests are found in the rainier parts of the peninsular plateau, the plains of Bihar, and the plains of Uttar Pradesh. Most of this forest region has now been cleared for cultivation and grazing.

44. Describe the root systems of trees found in thorn forests. Why are they adapted this way?

Answer: The scattered trees of thorn forests possess long, penetrating roots that reach deep into the soil. These roots tend to spread out in a radial pattern. They spread this way to reach for water.

45. Describe the succession of vegetation belts as one moves up the Himalayas.

Answer: As one moves up the Himalayas, one can observe a succession of natural vegetation belts. Tropical deciduous forests are found in the Himalayan foothills. Then come the wet temperate type of forests at a height of 1000 to 2000 metres. At a height of 1500 to 3000 metres, temperate forests are full of coniferous trees. As they approach the snowline, the trees get progressively stunted. Shrubs, scrubs and then alpine grasslands are found at higher elevations.

46. What kind of vegetation is found at an altitude of over 3600 metres?

Answer: At a high altitude of more than 3600 metres, temperate forests and grasslands give way to alpine vegetation. Silver fir, junipers, pines and birches are common trees. As one goes even higher, Tundra vegetation, which includes lichens and mosses, is also found.

47. What is ‘conservation’? Why is it urgently needed in India?

Answer: ‘Conservation’ is the management, protection and wise use of natural resources. As the need for conservation is urgent in the face of depletion, India needs a well-designed strategy to protect its resources.

48. How does urban growth lead to the destruction of forests?

Answer: For living purposes, forests have been destroyed. New cities have led to the destruction of forest areas.

49. Why is it important to control and restrict the grazing of domestic animals?

Answer: It is important to control and restrict the grazing of domestic animals because overgrazing by animals leads to the destruction of forests.

50. State any four reasons why we need to conserve our natural habitats.

Answer: We need to conserve our natural habitats for the following reasons:

• to maintain the habitats of plants and animals.
• to prevent their extinction.
• to prevent gaps in or damage to the food chain.
• to reduce the stress on resources.

51. What are the main aims behind the establishment of biosphere reserves?

Answer: The main aims behind the setting up of biosphere reserves are:

(i) Conserving and maintaining diversity and integrity of the natural heritage in its full form, i.e., physical environment, the flora and the fauna.
(ii) Promoting researches on ecological conservation and other aspects of environmental preservation.
(iii) Providing facilities for education, awareness and training.
(iv) To preserve the genetic variety in the crucial natural ecosystem settings.

52. What other measures, besides biosphere reserves, have been taken to protect flora and fauna?

Answer: Other measures to protect the flora and fauna include:

(i) Financial and technical assistance to all Botanical Gardens.
(ii) Project tiger, project rhino, project elephant and many other eco-developmental projects have been introduced.
(iii) 103 national parks, 563 wildlife sanctuaries and zoological gardens have been established.

53. Define the terms Biosphere, Flora, and Fauna.

Answer:

Biosphere: The part of the world where organisms can live.
Flora: Plant life in general especially plants of a certain region, environment or period.
Fauna: Animal life in general, as distinguished from flora, especially the indigenous animals of a certain region, environment or period.

54. Explain the key characteristics of Tropical Rainforests found in India.

Answer: The key characteristics of Tropical Rainforests, also known as Evergreen Forests, found in India are:

• They are only found in the rainy parts of India, i.e., the Western Ghats and the island groups of Lakshadweep, and the Andaman and Nicobar Islands.
• These forests grow bushy in areas that receive more than 200 cm of rainfall and experience a short dry season.
• In these forests, trees grow to the height of up to 60 metres or even above.
• As the region is warm and wet throughout the year, a variety of lush green vegetation is abundant, including trees, shrubs and creepers.
• There is no particular time for the trees to shed their leaves, so these forests appear green the whole year around.
• Ebony, mahogany, rubber, rosewood and cinchona are some of the commercially important trees of this forest.
• The forests have a unique characteristic of having a large number of species found together, which poses a problem as no particular variety can be targeted for commercial use.
• These forests are found in equatorial and coastal regions. Trees have very broad leaves to allow transpiration of surplus moisture.
• As the trees are very close to each other, they form a thick canopy and the vegetation forms a multi-layered structure.

55. Distinguish between Moist Deciduous and Dry Deciduous forests based on rainfall and location.

Answer: The distinctions between Moist Deciduous and Dry Deciduous forests are as follows:

Moist Deciduous Forests are located in areas that receive 200 cm to 100 cm of rainfall. Their main locations are the Eastern slopes of the Western Ghats, West Odisha, Chhattisgarh, Jharkhand, North Eastern States, and the Himalayan Foothills.

Dry Deciduous Forests are located in areas that receive 100 cm to 70 cm of rainfall. These forests are mostly found in the rainier parts of the peninsular plateau, the Plains of Bihar, and the Plains of Uttar Pradesh.

56. Describe the vegetation and its adaptations found in the Thorn Forests and Scrubs of India.

Answer: The vegetation in Thorn Forests and Scrubs consists of thorny trees and bushes. The main plant species are Cacti, Palms, Acacias, and Euphorbias. The vegetation is composed of low and open forests with short thorny trees, thorny bushes, scrubs, and grasses in between.

The plants in these forests have several adaptations:

• The scattered trees possess long, penetrating roots that reach deep into the soil and spread out in a radial pattern to reach for water.
• The stems are succulent to conserve water.
• The leaves of the trees are thick and tiny in order to have minimum evaporation.

57. Explain the changes in natural vegetation that occur with increasing altitude in mountainous regions.

Answer: Increasing height, or altitude, causes a decrease in temperature in mountainous regions, which leads to a change in natural vegetation at different altitudes. One can observe a succession of natural vegetation belts in the same order as seen from the tropical to the tundra regions.

• At the Himalayan foothills, Tropical deciduous forests are found.
• At a height of 1000 to 2000 metres, wet temperate types of forests are found, which include broad-leaf trees of the evergreen variety.
• At a height of 1500 to 3000 metres, temperate forests are full of coniferous trees like Cedar, Spruce, Pine, and Silver fir.
• At a high altitude of more than 3600 metres, temperate forests and grasslands give way to alpine vegetation. Silver fir, junipers, pines and birches are common trees.
• As they approach the snowline, the trees get progressively stunted. Shrubs, scrubs, and then alpine grasslands are found at higher elevations. The growth of trees becomes stunted as they near the snowline, and after this gradual change, the shrubs and scrubs merge into the Alpine grasslands.
• As one goes even higher, Tundra vegetation appears, which includes lichens and mosses.

58. What is conservation? Explain the methods of afforestation and checking urban growth for conserving forests.

Answer: ‘Conservation’ is the management, protection and wise use of natural resources. The word conserve is coined from the two Latin words ‘con’ which means together and ‘servare’ which means to preserve. Hence, conservation means to preserve and keep together.

Two methods for conserving forests are:

(a) Afforestation: We should plant more trees, which is known as afforestation. All communities should be made aware of the importance of forests, which will prevent the reckless cutting of trees. People living near forests should also be made aware of the danger of forest fires and how they cause the depletion of forest resources.
(b) Check on Urban Growth: For living purposes, forests have been destroyed, and new cities have led to the destruction of forest areas. Therefore, urban growth should be properly planned so that the minimum area under forests is maintained.

59. What are biosphere reserves? Name any six biosphere reserves in India and their locations.

Answer: Biosphere reserves have been established in the country to protect and conserve the biodiversity of India. They are multipurpose protected areas where each plant and animal species finds a protected, necessary environment in its natural habitat. A biosphere reserve is a forest area where various types of flora and fauna are preserved in a natural environment.

Six biosphere reserves in India and their locations are:

• Nilgiri – Tamil Nadu, Kerala, Karnataka
• Nanda Devi – Uttarakhand
• Gulf of Mannar – Tamil Nadu
• Nokrek – Meghalaya
• Sundarbans – West Bengal
• Manas – Assam

60. Why is the conservation of natural vegetation a national problem? How can people’s involvement help solve it?

Answer: The conservation of natural vegetation is a national problem because the rapid destruction of forests has become a major cause of concern. Forests are an important resource that must be preserved for use by future generations. This problem has to be tackled in a systematic and planned manner.

People’s involvement in conservation is of vital importance. As much as the government’s involvement is required, people’s participation is equally necessary. For example, all communities can be made aware of the importance of forests, which will help prevent the reckless cutting of trees. People all over the world have practised conservation for hundreds of years, showing that their involvement is key to solving the problem.

61. Describe the medicinal uses of any four plants.

Answer: The medicinal uses of four plants are:

Kachnar: It cures asthama and ulcers. Its buds and roots are good for digestive problems, and its roots cure snake bites.
Babool: Its leaves are used as a tonic, cure for eye sores, and medicine for cough. Its bark dust is a cure for dog bite.
Arjun: Its fresh juice cures earache. It is good for blood pressure problems and heart diseases.
Neem: It is an antibiotic and antibacterial.

62. Explain the interdependence between plants, animals, and their physical environment in forming an ecosystem.

Answer: An ecosystem is a complex set of relationships among the living resources, habitats, and residents of an area, which includes plants, trees, animals, fish, birds, micro-organisms, water, soil, and people.

Interdependence is a common part of life in an area where plants and animals coexist. They also depend a lot on their physical environment. The climate influences the distribution of plants and animals, and other interrelated factors that affect them are soil, relief, and drainage. This interdependence between plants, animals, and their physical environment is what forms an ecosystem.

63. What are the main features of Tropical Deciduous forests? Why are they commercially valuable?

Answer: The main features of Tropical Deciduous forests are:

• They are the most widespread forests in India and are also known as monsoon forests.
• These forests are spread over a region that gets rainfall between 70 cm and 200 cm.
• For about six to eight weeks in summer, the trees of monsoon forests shed their leaves. As every species of tree has its own time of shedding leaves, these forests never appear barren at any particular time of the year.
• The trees, like neem and mango, have widespread out branches. Their leaves are smaller in size than those of the rainforests to reduce transpiration, and the trees also have less height than evergreen trees.

These forests are commercially valuable because the trees are prized for their hardwood, and commercially valuable timber is collected from them. Some of the commercially important species from these forests are teak, khair, shisham, sal, bamboo, kusum, arjun, mulberry, and sandalwood.

64. Describe in detail the features, distribution, and important tree species of Tropical Evergreen forests in India.

Answer: Tropical Evergreen forests, also known as Tropical Rainforests, have the following features:

These types of forests grow bushy in areas that receive more than 200 cm of rainfall and experience a short dry season. As the region is warm and wet throughout the year, a variety of lush green vegetation is abundant here, including trees, shrubs and creepers. In these forests, trees grow to a height of up to 60 metres or even above. There is no particular time for the trees to shed their leaves, so these forests are green in appearance the whole year around. The trees have very broad leaves to allow transpiration of surplus moisture. As the trees are very close to each other, they form a thick canopy, and the vegetation forms a multi-layered structure. A unique characteristic of these forests is having a large number of species found together. This poses a problem as no particular variety can be targeted for commercial use.

These forests are found in equatorial regions and coastal regions. In India, Tropical rainforests are only found in the rainy parts of India, i.e., the Western Ghats and the island groups of Lakshadweep, and the Andaman and Nicobar Islands.

Ebony, mahogony, rubber, rosewood and cinchona are some of the commercially important trees of this forest.

65. Explain the characteristics, types, and distribution of Tropical Deciduous forests in India.

Answer: The most widespread forests in India are the tropical deciduous forests, also known as the monsoon forests. These forests are spread over a region that gets rainfall between 70 cm and 200 cm. For about six to eight weeks in summer, the trees of monsoon forests shed their leaves. As every species of tree has its own time of shedding leaves, these forests never appear barren at any particular time of the year. The trees have widespread out branches like the neem and mango. Leaves are smaller in size than that of the rainforests to reduce transpiration. The trees also have less height than evergreen trees. The trees are prized for their hardwood as commercially valuable timber is collected from these forests.

The abundance or lack of water plays an important role in the further division of monsoon forest type. There are two types of tropical deciduous forests:

(i) Moist deciduous forests: These are located in areas that receive 200 cm to 100 cm rainfall. Their main locations are the Eastern slopes of Western Ghats, West Odisha, Chhattisgarh, Jharkhand, North Eastern States, and the Himalayan Foothills. Teak is the most important and prominent species of these forests. Other commercially important species are khair, shisham, sal, bamboo, kusum, arjun, mulberry and sandalwood.
(ii) Dry deciduous forests: These are located in areas that receive 100 cm to 70 cm rainfall. Most of these forests are in the rainier parts of the peninsular plateau, the plains of Bihar, and the plains of Uttar Pradesh. In these forests, open stretches of teak, sal, peepal, and neem grow. Most of this forest region has now been cleared for cultivation and grazing.

66. Compare and contrast the characteristics of Tropical Rainforests and Tropical Thorn Forests in India.

Answer: The characteristics of Tropical Rainforests and Tropical Thorn Forests are very different, mainly due to the amount of rainfall they receive.

Tropical Rainforests, or Evergreen Forests, grow in areas that receive more than 200 cm of rainfall and have a short dry season. The region is warm and wet throughout the year. The vegetation is lush and includes trees, shrubs, and creepers. Trees grow to a height of 60 metres or even above and form a thick canopy and a multi-layered structure. They have very broad leaves to allow transpiration of surplus moisture and do not shed their leaves at any particular time, so they appear green all year round.

Tropical Thorn Forests and Scrubs are found in regions with less than 70 cm of rainfall. The vegetation consists of low and open forests with short thorny trees and thorny bushes, scrubs, and grasses in between. The scattered trees in these forests possess long, penetrating roots that reach deep into the soil and spread out in a radial pattern to reach for water. The stems are succulent to conserve water, and the leaves are thick and tiny to have minimum evaporation.

67. Describe the different types of vegetation found in the Himalayan region, explaining the changes at various altitudes.

Answer: In the mountainous regions, increasing height (altitude) causes decreasing temperature, which leads to a change in natural vegetation at different altitudes. One can observe a succession of natural vegetation belts in the same order as seen from the tropical to the tundra regions.

• In the Himalayan foothills, Tropical deciduous forests are found.
• At a height of 1000 to 2000 metres, the wet temperate type of forests are found. The broad-leaf trees of evergreen variety are found in these forests.
• At a height of 1500 to 3000 metres, Temperate forests are found, which are full of coniferous trees that include Cedar, Spruce, Pine, Silver fir, and Deodar. These temperate forests occur on the southern slopes of the Himalayas.
• At a high altitude of more than 3600 metres, temperate forests and grasslands give way to alpine vegetation. Silver fir, junipers, pines and birches are common trees.
• As they approach the snowline, the trees get progressively stunted. Shrubs, scrubs and then alpine grasslands are found at higher elevations. At even higher altitudes, the temperate grasslands become a common occurrence.
• As one goes even higher, Tundra vegetation is found, which includes lichens and mosses.

68. Why is the conservation of forests and wildlife essential for human survival? What steps has India taken for their conservation?

Answer: Conservation is the management, protection and wise use of natural resources. It is essential because forests are an important resource, and we need to conserve this renewable resource. They must be preserved for use by future generations. We need to conserve to maintain the habitats of plants and animals, prevent their extinction, prevent gaps in or damage to the food chain, reduce the stress on resources, and prevent the rapid depletion of resources. All Indians must understand the importance of the preservation of our natural ecosystem for preserving our existence and its survival in the harsh future.

India has taken several steps for the conservation of forests and wildlife. Some important ways for conserving forests are:

(a) Afforestation: We should plant more trees. All communities should be made aware of the importance of forests to prevent reckless cutting of trees. People living near forests should be made aware of the danger of forest fires.
(b) Check on Urban Growth: For living purposes, forests have been destroyed. Urban growth should be properly planned so that the minimum area under forests is maintained.
(c) Check on Grazing: Overgrazing by animals leads to the destruction of forests. There should be restrictions and control on grazing by domestic animals.

Specific laws have been made to protect and conserve fragile habitats, known as Eco-sensitive Zones. There are also specific acts to protect certain areas such as the No Development Zone at Numaligarh East of Kaziranga, the Doon Valley, and the Aravalli Hills. There are also programmes for the conservation of wetlands, mangroves and coral reefs.

Eighteen biosphere reserves have been set up in the country to protect flora and fauna. The main aims are conserving diversity, promoting ecological research, and providing facilities for education and training.

Other measures to protect flora and fauna include financial and technical assistance to all Botanical Gardens; projects like project tiger, project rhino, and project elephant; and the establishment of 103 national parks, 563 wildlife sanctuaries and zoological gardens.

69. Explain the five major types of vegetation found in India and the climatic factors responsible for their distribution.

Answer: The main types of vegetation prevalent in India are:

(i) Tropical Rainforests
(ii) Tropical Deciduous Forests
(iii) Tropical Thorn Forests and Scrubs
(iv) Temperate Forests with Grasslands
(v) Alpine and Tundra Grasslands

The distribution of plants and animals is affected by factors like climate, soil, relief and drainage. Temperature or heat is a climatic factor, just like precipitation, which determines which plant species can flourish under some particular climatic conditions.

Tropical Rainforests are found in areas that receive more than 200 cm of rainfall and where the region is warm and wet throughout the year.

Tropical Deciduous Forests are spread over regions that get rainfall between 70 cm and 200 cm.

Tropical Thorn Forests and Scrubs are found mainly in regions of less than 70 cm of rainfall.

Temperate Forests with Grasslands and Alpine and Tundra Vegetation are found in mountainous regions. Here, increasing height (altitude) causes decreasing temperature, which causes a change in natural vegetation at different altitudes. Temperate forests are found between 1500 to 3000 metres, while Alpine and Tundra vegetation flourishes at heights above 3600 metres.