NCERT Solution - Natural Vegetation and Wildlife Class 9 Notes | EduRev

Page No. 51 

Q.1. Choose the right answer from the four alternatives given below:

Q.2. Answer the following questions briefly.
(i) What factors are responsible for the distribution of plants and animals in India?
(ii) What is a bio reserve? Give two examples.
(iii) Name two animals having their habitat in montane and tropical types of vegetation.
Ans. (i) The factors that are responsible for the distribution of plants and animals in India are:

(a) Relief

• Land: The nature of land influences the type of vegetation.
  A land that is flat is devoted to agriculture, undulating land encourages the growth of grass and woodlands where animals live.
• Soil: Different types of soils support different types of vegetation.
  Cactus and thorny bushes grow well in the desert, marshy deltaic soils, and conical trees in the hill slopes.

(b) Climate

• Temperature affects the types of vegetation and growth. Trees’ growth differs depending on where they are located in the mountains.
• The variation in the duration of sunlight affects the growth of trees. In summer, trees grow faster as the sun shines for a longer time.
• Precipitation: Areas of heavy rainfall have denser vegetation than areas of less rain. There is a dense growth of trees in regions where the South West Summer Monsoons cause heavy rain.
  Example: Windward slopes of the Western Ghats.

(ii)  A bio reserve is an ecosystem having plants and animals of unusual scientific and natural instinct. These are preserved in their natural environment.

(iii) The Tibetan antelope and the Kashmir stag have their habitat in the Montane vegetation. In the Tropical Evergreen Forests bats and sloths are found and in the Tropical Deciduous Forests, snakes and tortoises exist.

Q.3. Distinguish between
(i) Flora and Fauna
(ii) Tropical Evergreen and Deciduous Forests
Ans. (i) The word ‘flora’ is used to denote plants of a particular region or period and the species of animals are referred to as ‘fauna’.(ii) Tropical Evergreen Forests:

• Rainfall is very heavy, over 200 cm of rain.
• Forests appear green all year round as the trees shed their leaves at different times of the year.
• Vegetation is luxuriant, multilayered, and of great variety.
• Commercially important trees are ebony, mahogany, rosewood, rubber, and cinchona.
• Trees are tall and have straight trunks.

Deciduous Forests:

• They are also known as Monsoon Forests.
• These are found where the rainfall is between 70 cm - 200 cm.
• Trees shed their leaves for about 6-8 weeks in the dry summer.
• These forests are divided into Dry and Wet Deciduous Forests.
• Wet Deciduous Forests are found in the northeast states, foothills of the Himalayas, Jharkhand, West Odisha, Chhattisgarh, and the eastern slopes of the Western Ghats. Important trees are bamboos, sal, shisham, Khair, Arjun, etc.
• Dry Deciduous Forests are found in the plains of Bihar, Uttar Pradesh, and the rainier parts of the Deccan plateau. Important trees are teak, sal, peepal, and neem. Trees have been cleared in some parts for cultivation and for grazing.

Q.4. Name different types of vegetation found in India and describe the vegetation of high altitudes.
Ans. 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

In mountainous areas, the decrease in temperature with increasing altitude leads to the corresponding change in natural vegetation:

• The foothills of the Himalayas, Shiwaliks, have tropical moist deciduous flora. Sal and bamboo are important trees.
• They are followed by the wet hill forests. They lie between about 1,000 to 2,000 m. Important trees are oak, chestnut, ash, birch, etc.
• Between 1,500 and 3,300 m above sea level, there occur the well-known coniferous forests. Pine, deodar, silver fir, spruce, etc., are some dominant trees.
• Above the coniferous forests lie the alpine forests at an altitude of about 3,600 m. Important trees are silver fir, pine, birch, etc. Alpine vegetation is found at places over 3,600 m in height. The trees common to these are silver fir, junipers, pines, and birches. 
• They get stunted as they approach the show-line. Through shrubs and scrubs, they ultimately merge into the Alpine grasslands. Tundra vegetation is limited to lichens and mosses.

Q.5. Quite a few species of plants and animals are endangered in India. Why?
Ans. Many plants and animals are endangered in India due to a number of reasons:

• Hunting of animals for commercial purposes.
• Pollution due to chemical and industrial waste, acid deposits.
• Introduction of alien species.
• Reckless cutting of the forests to bring land under cultivation and inhabitation.

As a result of these activities about 1300 plant species are endangered and 20 plant species have become extinct. Quite a few animal species are also endangered.

Q.6. Why has India a rich heritage of flora and fauna?
Ans. India has a rich heritage of flora and fauna due to the following reasons:

• India is a diverse country with various relief features (i.e. mountains, plateaus, plains, etc.) These regions consist of different types of vegetation that support different types of animals.
• There is the availability of different types of soil which facilitates a base for different types of vegetation.
• There is variation in the climatic conditions of India (Temperature, humidity, etc.). It differs from north to south and east to west. Thus, supporting a large variety of flora and fauna.
• India has a monsoon type of climate where rainfall varies from 20 cms to 300 cms distributed throughout the year, supporting a large amount of flora and fauna.
• Variation in the duration of sunlight at different places due to differences in latitude and altitude.