NCERT Solutions for Class 9 Social Science Chapter 5 – Natural Vegetation and Wildlife
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Page No: 43
1. Why are the southern slopes in Himalayan region covered with thick vegetation cover as compared to northern slopes of the same hills?
Answer
The northern slopes of the hills in Himalayan region are at high altitude and have low temperature or are snow covered. This does not allow much vegetation. In the southern part of the hills there are plains and valleys watered by rivers and with fertile soil and pleasant temperature levels all required for dense growth of vegetation.
2. Why have the western slopes of the Western Ghats covered with thick forests and not the eastern slopes?
Answer
The westward facing slopes receive much more rain than the eastward facing slopes and the Western Ghats are considerably wetter than the dry Deccan to the east.
Page No: 51
Exercise
1. Choose the right answer from the four alternatives given below:
(ii) Cinchona trees are found in the areas of rainfall more than:
(a) 100 cm
(b) 50 cm
(c) 70 cm
(d) Less than 50 cm
► (a) 100 cm
(iii) In which of the following states is the Simplipal bioreserve located?
(a) Punjab
(b) Delhi
(c) Odisha
(d) West Bengal
► (c) Odisha
(iv) Which one of the following bio-reserves of India is not included in the world network of bioreserve?
(a) Manas
(b) Nilgiri
(c) Gulf of Mannar
(d) Nanda Devi
► (a) Manas
Page No: 52
2. Answer the following questions briefly.
(i) Define an ecosystem.
(ii) What factors are responsible for the distribution of plants and animals in India?
Page No: 43
1. Why are the southern slopes in Himalayan region covered with thick vegetation cover as compared to northern slopes of the same hills?
Answer
The northern slopes of the hills in Himalayan region are at high altitude and have low temperature or are snow covered. This does not allow much vegetation. In the southern part of the hills there are plains and valleys watered by rivers and with fertile soil and pleasant temperature levels all required for dense growth of vegetation.
2. Why have the western slopes of the Western Ghats covered with thick forests and not the eastern slopes?
Answer
The westward facing slopes receive much more rain than the eastward facing slopes and the Western Ghats are considerably wetter than the dry Deccan to the east.
Page No: 51
Exercise
1. Choose the right answer from the four alternatives given below:
(i) To which one of the following types of vegetation does rubber belong to?
(a) Tundra
(a) Tundra
(b) Tidal
(c) Himalayan
(d) Tropical Evergreen
► (d) Tropical Evergreen(ii) Cinchona trees are found in the areas of rainfall more than:
(a) 100 cm
(b) 50 cm
(c) 70 cm
(d) Less than 50 cm
► (a) 100 cm
(iii) In which of the following states is the Simplipal bioreserve located?
(a) Punjab
(b) Delhi
(c) Odisha
(d) West Bengal
► (c) Odisha
(iv) Which one of the following bio-reserves of India is not included in the world network of bioreserve?
(a) Manas
(b) Nilgiri
(c) Gulf of Mannar
(d) Nanda Devi
► (a) Manas
Page No: 52
2. Answer the following questions briefly.
(i) Define an ecosystem.
(ii) What factors are responsible for the distribution of plants and animals in India?
(iii) What is a bio-reserve? Give two examples.
(iv) Name two animals having habitat in different types of vegetation.
Answer
(i) All the plants and animals in an area are interdependent on each other. The plants and animals, alongwith their physical environment make the ecosystem. Interrelation between plants and animals in the natural environment is called Ecosystem.
(ii) Factors responsible for the distribution of plants and animals in India are:
(a) Relief: Land and soil
(b) Climate: Temperature, Humidity, Photoperiod and Precipitation.
(b) Climate: Temperature, Humidity, Photoperiod and Precipitation.
(iii) Bio-reserves are the large areas where vegetation, wildlife and the environment are conserved to preserve the biological diversity. In totality there are 14 bio-reserves in India. For e.g. Sunderbans Bio-reserve in West Bengal and Nanda Devi Bio-reserve in Uttaranchal.
(iv) Tropical animals: Tiger, Elephant
Montane animals: Snow Leopard, Spotted dear
3. Distinguish between
(i) Flora and Fauna
(ii) Tropical Evergreen and Deciduous forests
Montane animals: Snow Leopard, Spotted dear
3. Distinguish between
(i) Flora and Fauna
(ii) Tropical Evergreen and Deciduous forests
Answer
(i)
Flora
|
Fauna
|
| The Plant species of particular region or period are called Flora. | The animal species of particular region or period are called Fauna. |
(ii)
Tropical Evergreen Forests
|
Tropical Deciduous Forests
|
| These are also called Rain Forest | These are also called Monsoon Forest. |
| Since the region is warm and wet throughout the year, there is no definite time for the trees to shed their leaves | The trees shed their leaves for about six to eight weeks in dry summer |
| Examples: ebony, mahogany, rubber, rosewood | Examples: teak, bamboo, sandalwood, peepal, neem |
| Common animals found in these forests are elephants and monkeys. | Common animals found in these forests are lions and tigers |
| Present in areas receiving more than 200 cm of rainfall | Present in areas receiving rainfall between 200 cm and 70 cm |
4. Name different types of vegetation found in India and describe the vegetation of high altitudes.
Answer
The different types of vegetation found in India are:
(i) Tropical Evergreen Forests
(ii) Tropical Deciduous Forests
(iii) Tropical Thorn Forests and Scrubs
(iv) Montane Forests
(v) Mangrove Forests
Alpine vegetation is found at places over 3,600 m in height. The trees common to these are silver fir, junipers, pines and birches. The trees get stunted as they reach the snow line. There are shrubs and scrubs that ultimately merge into Alpine grasslands. Tundra vegetation is limited to lichens and mosses.
5. Quite a few species of plants and animals are endangered in India. Why?
Answer
Few species of plants and animals are endangered in India because of:
→ Increase in population.
→ Urbanization and Industrialization.
→ Large scale deforestation.
→ Pollution.
→ Hunting for pleasure and commercial purpose, etc.
6. Why has India a rich heritage of flora and fauna?
Answer
India has a rich heritage of flora and fauna due to following reasons:
→ India is a diverse country with different relief features (i.e. mountains, plateaus, plains, etc.) Different types of vegetations are found in these regions and the vegetations support different type of animals.
→ Availability of different types of soil providing base for different type of vegetations.
→ Variation in the climatic conditions (Temperature, humidity, etc.). Climate of India differs from north to south and east to west. Thus, supporting large variety of flora and fauna.
→ India has a monsoon type of climate where rainfall varies from 20 cms to 300 cms distributed through out the year supporting large amount of flora and fauna.
→ Variation in the duration of sunlight at different places due to difference in the latitude and altitude.
Map Skills
On an outline map of India, label the following.
(i) Areas of Evergreen Forests
(ii) Areas of Dry Deciduous Forests
(iii)Two national parks each in Northern, Southern, Eastern and Western parts of the Country
Answer
