CBSE Class 11

Detailed, Step-by-Step NCERT Solutions for Class 11 Geography Chapter 5 Natural Vegetation Questions and Answers were solved by Expert Teachers as per NCERT (CBSE) Book guidelines covering each topic in chapter to ensure complete preparation.

Natural Vegetation NCERT Solutions for Class 11 Geography Chapter 5

Natural Vegetation Questions and Answers Class 11 Geography

Chapter 5

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

(i) Sandalwood is an example of:
(a) Evergreen forest
(b) Deciduous forest
(c) Deltaic forest
(d) Thorny forest
Answer:
(b) Deciduous forest

(ii) Which one the following was the purpose of Project Tiger?
(a) to kill tigers
(b) to put tigers in the zoo
(c) to protect tigers from illegal hunting
(d) to make films on tigers
Answer:
(c) to protect tigers from illegal hunting

(iii) In which one of the following states is the Nandadevi Biosphere Reserve situated?
(a) Bihar
(b) Uttar Pradesh
(c) Uttaranchal
(d) Orissa
Answer:
(c) Uttranchal

(iv) How many of the following numbers of Biosphere reserves are recognised by the IUCN?
(a) one
(b) two
(c) three
(d) four
Answer:
(d) four

(v) Which one of the following proportion of area of the country was targeted to be under forest in Forest Policy of India?
(a) 33
(b) 44
(c) 55
(d) 22
Answer:
(a) 33

Question 2.
Answer the following questions in about 30 words :
(i) What is natural vegetation? Under what climatic conditions do tropical evergreen forests develop?
Answer:
Natural vegetarian means plant community which grows in wild without human aid and adapts to the constraints of natural environment in size, structure and fruit requirements. The tropical evergreen forests are found in warm and humid areas with an annual precipitation of over 200 cm. and mean annual temperature above 22°C.

(ii) What do you understand by social forestry?
Answer:
Social forestry means the management and protection of forests and afforestation on barren lands with a purpose of helping in the environmental, social and rural development.

(iii) Define Biosphere reserves.
Answer:
Biosphere reserve is a unique representative ecosystem of terrestrial and coastal areas which are internationally recognised, within the framework of UNESCO’s Man and Biosphere (MAB) programme.

(iv) What is the difference between forest area and forest cover?
Answer:
Forest area – It is the area notified and recorded as forest land irrespective of the existence of trees.
Actual forest – It is the area actually occupied by forest. It is based on aerial photographs and satellite imageries.

Question 3.
Answer the following questions in not more than 150 words :
(i) What steps have been taken up to conserve forests?
Answer:
The conservation of forests is of great importance to the survival and prosperity of humankind. The government of India proposed a nationwide forest conservation policy in 1952 which was further modified in 1988. According to new forest policy the government will emphasize on sustainable forest management in order to conserve and expand forest reserve.
The policy aimed at:

• Bringing33%of its geographical areas under forest cover, which is 6% more than the area at the national level.
• To maintain environmental stability and to restore forests.
• To conserve the natural heritage of the country, its biological diversity and genetic pool.
• To check soil erosion, extension of the desert lands and reduction of floods and droughts.
• To increase the forest cover through social forestry and afforestation.
• Toincreasetheproductivityofforeststomaketimber,fuel,fodder and food available to rural and tribal population dependent on forests.
• To encourage the substitution of wood.
• To create a massive peoples movement involving women to encourage planting of trees and to stop felling of trees.

Based on the forest conservation policy following steps were initiated :

(i) Social forestry – Social forestry programme has encouraged farmers to plant trees on their own farms, wood lots are planted by the forest department for the needs of the community especially along road sides, canal banks and other such public lands. This programme has classified into urban, rural and farm forestry.

(ii) How can people’s participation be effective in conserving forests and wildlife?
Answer:
People can help in raising the social forestry programme. They can plant trees on their own farms, wood lots are planted by the forest department for the needs of the community especially along road sides, canal banks and other such public lands and community wood lots are planted by the community themselves on economically lands to be shared equally by them.

Wild life conservation has a very large ambit for the well being of ‘ humankind. This can be achieved only when every individual understands f its significance and contributes his bit. For this purpose Project Tiger (1973) and Project Elephant (1992) have been launched to conserve these species.

The main objective of the scheme is to ensure the maintenance of the viable population of tiger and preserve areas of biological importance as natural heritage for their benefit. For this purpose of effective conservation of flora and fauna special steps have been initiated. People can help in maintaining the stability of ecosystem by forestering other trophic levels in food chain which is essential to ensure an ecologically viable population of tiger.

Activity:
1 On the outline map of India, mark and label the following :
(i) Areas having Mangrove forests.
(ii) Biosphere Reserves, Nanda Devi, Sunderban, Gulf of Mannar and Nilgri.
(iii) Mark the location of Forest Survey of India Head Quarter.
Answer:
Forestry Survey of India Head Quarter situated is at Dehradun.
(See Map and identify place, marked for self doing.)

Detailed, Step-by-Step NCERT Solutions for Class 11 Geography Chapter 4 Climate Questions and Answers were solved by Expert Teachers as per NCERT (CBSE) Book guidelines covering each topic in chapter to ensure complete preparation.

Climate NCERT Solutions for Class 11 Geography Chapter 4

Climate Questions and Answers Class 11 Geography Chapter 4

Question 1.
Choose the right answer from the four alternatives given below :
(i) What causes rainfall on the coastal areas of Tamil Nadu in the beginning of winters?
(a) South-west monsoon
(b) North-eastern monsoon
(c) Western disturbances
(d) Local factors
Answer:
(b) North-eastern monsoon

(ii) What is the proportion of area of India which receives annual rainfall less than 75 cm?
(a) Half
(b) Two third
(c) One-third
(d) Three-fourth
Answer:
(d) Three-fourth

(iii) Which one of the following is not a fact regarding South India?
(a) Diurnal range of temperature is less here.
(b) Annual range of temperature is less here.
(c) Temperatures here are high throughout the year.
(d) Extreme climatic conditions are found here.
Answer:
(d) Extreme climate conditions are found here.

(iv) Which one of the following phenomenon happens when the sun shines vertically over the Tropic of Capricorn in the southern hemisphere?
(a) High pressure develops over North-western India due to low temperatures.
(b) Low pressure develops over North-western India due to high temperatures.
(c) No changes in temperature and pressure occur in north-western India.
(d) ‘Loo’ blows in the north-western India.
Answer:
(b) Low pressure develops over North-western India due to high temperature.

(v) In which of the following states in India do we find ‘As’ type of climate as per Koeppen’s classification?
(a) In Kerala and coastal Karnataka
(b) In Andaman and Nicobar Islands
(c) On Coromandal coast
(d) In Assam and Arunachal Pradesh
Answer:
(c) On Coromandal coast

Question 2.
Answer the following questions in about 30 words.

(i) What are the three important factors which influence the mechanism of Indian weather?
Answer:
Temperature, pressure and air.

(ii) What is the Inter-Tropical Convergene Zone?
Answer:
The westerly jet stream withdraws from the Indian region. ITCZ is a zone of low pressure, inviting inflow of winds from different directions.

(iii) What is meant by ‘bursting of monsoon’? Name the place of India which gets highest rainfall.
Answer:
The first rain of the monsoon brings down the temperature substantially. This sudden onset of the moisture-laden winds associated with violent thunder and lightening, is often termed as the ‘break’ or ‘burst’ of monsoon.

(iv) Define climatic region. What are the basis of Koeppen’s classification?
Answer:
Koeppen’s classification is based on monthly values of temperature and precipitation.

(v) Which type(s) of cyclones cause rainfall in north-western India during winter? Where do they originate?
Answer:
In north-western India, some weak temperate cyclones, after getting humidity from the Mediterranean sea cause rainfall in Punjab, Haryana, Delhi and western Uttar Pradesh. It is highly beneficial forrabi crops, especially for wheat.

Question 3.
Answer the following questions in not more than 125 words :
(i) Notwithstanding the broad climatic unity, the climate of India has many regional variations. Elaborate this statement giving suitable example.
Answer:
The monsoon regime emphasises the unity of India with rest of the south-east Asian region. This view of broad unity of the monsoon type of climate should not lead to ignoring the regional variations in climate which differentiate the weather and climate of different regions of India. For example, the climate of Kerala and Tamil Nadu in the south is so different from that of Uttar Pradesh and Bihar in the north, and yet all of these have a monsoon type of climate.

The climate of India has many regional variations expressed in the pattern of winds, temperature and rainfall, rhythm of seasons and the degree of wetness or dryness. These regional variations may be described as sub-types of monsoon climate.

In summer the mercury occasionally touches 55°C in the western deserts, it drops down to as low as minus 45°C in winter around Leh.

Churu in Rajasthan may record a temperature of 50°C or more in June while 19°C in Tawang (Arunacha! Pradesh) in the same month. On a December night, the temperature in Drass (Jammu and Kashmir) may drop down to minus 45°C while Thiruvananthapuram or Chennai on the same night records 20°C or 22°C.

The above examples confirm that there are seasonal variations in temperature from place to place and from region to region in India. If we take a single place and confirm to temperature recording for just 24 hours, variations are not less striking. In Kerala and in the Andaman Islands, the difference between day and night temperature may be hardly 7°C or 8°C. But in Thar desert, if the day temperature is around 50°C, at night it may drop up to 15°C to 20°C.

Let us see the regional variations in precipitation. While snowfall occurs in the Himalaya, it only rains over the rest of the country. Tura situated in the Garo hills of Meghalaya may get an amount of rainfall in single day which is equal to 10 years of rainfall at Jaisalmar. Most parts of the country get rainfal 1 during June-September but on the coastal area of Tamil Nadu, it rains in the beginning of winter season.Inspite of these differences and variations, the climate of India is monsoonal in rhythm and character.

(ii) How many distinct seasons are found in India as per the Indian Meteorological Departmen t? Discuss the weather conditions associated with any one season in detail.
Answer:
The meteorologists usually fecognisethe followingfour seasons :
(a) The cold weather season,
(b) The hot weather season,
(c) The south-west monsoon season; and
(d) The retreating monsoon season.

The cold weather season :
Temperature – The cold-w eather season usually begins in the mid of November in northern India. January and February’ are the coldest months. The mean daily temperature remains below 21°C over most parts of the northern India. The night temperature may be quite low, often drops to freezing point. There are three main reasons which are responsible for this :

• States like Punjab, Haryana, Rajasthan being away from the sea coast are devoid of warm and moist winds.
• Snowfall in the Himalayan ranges increases the cold.
• Around February, the cold winds from Caspian Sea and Turkmenistan bring cold wave over north-western parts of lndia.

December and January are the coldest months in the interior parts of the country with mean daily temperature is 28°C to 19°C in the north-west.

The peninsular region of India, however, does not have any well- defined cold weather season. There is hardly any change in temperature in coastal region because of the influence of the sea and the nearness of equator. For example, the mean temperature for January at Thiruvananthapuram is as high as 31°C and for June it is 29.5°C.

Pressure and winds – By the end of December sun shines vertically over the Tropic of Capricorn in the southern hemisphere. The weather is characterised by feeble high pressure conditions over the northern plain. In south India, air pressure is not so much. As a result, winds start blowing from north-western high pressure zone to the low air pressure zone over Indian Ocean in the south. Due to low pressure the light winds blow outwards with a low velocity of about 3 to 5 km. During the winters, the weather in India is fine and really delightful.

The fine weather conditions, at intervals, get disturbed by shallow cyclonic depressions, known as western disturbances. The westerly jet stream plays a key role in steering these depressions into India in each of the winter months, generally between December and January.

Winter monsoon winds do not cause rainfall as they blow from land to sea, because they have little humidity. So most parts of India do not have rainfall in winter season.

But in north-western India, some weak temperate cyclones cause rainfall in Punjab, Haryana, Delhi and Western Uttar Pradesh. Central parts of India and northern parts of southern peninsula also get winter rainfall.

Arunachal Pradesh and Assam also get rain in winter due to western disturbances. During October and November, north-east monsoon causes rainfall over Tamil Nadu coast.

Detailed, Step-by-Step NCERT Solutions for Class 11 Geography Chapter 3 Drainage System Questions and Answers were solved by Expert Teachers as per NCERT (CBSE) Book guidelines covering each topic in chapter to ensure complete preparation.

Drainage System NCERT Solutions for Class 11 Geography Chapter 3

Drainage System Questions and Answers Class 11 Geography Chapter 3

Question 1
Choose the right answer from the four alternatives given below :
i. Which one of the following rivers is known as the ‘Sorrow of Bengal’?
(a) The Gandak
(b) The Son
(c) The Kosi
(d) The Damodar
Answer:
(d) The Damodar

ii. Which one of the following rivers has the largest river basin in India?
(a) The Indus
(b) The Brahmaputra
(c) The Ganga
(d) The Krishna
Answer:
(a) The Indus.

iii. Which one of the following rivers is not included in ’ Panchnad ’ ?
(a) The Ravi
(b) The Chenab
(c) The Indus
(d) The Jhelum
Answer:
(c) The Indus

iv. Which one of the following rivers flows in the rift valley?
(a) The Son
(b) The Narmada
(c) The Yamuna
(d) The Luni
Answer:
(b) The Narmada

v. Which one of the following is the place of confluence of the Alkananda and the Bhagirathi?
(a) Vishnu Prayag
(b) Rudra Prayag
(c) Karan Prayag
(d) Deva Prayag
Answer:
(d) Deva Prayag

Question 2.
State the differences between the following :
(a) River Basin and Watershed
(b) Dendritic and Trellis drainage pattern
(c) Radial and Centripetal drainage pattern
(d) Delta and Estuary
Answer:
(a) River Basin and Watershed

(b) Dendritic and Trellis drainage pattern.

(c) Radial and Centripetal drainage pattern

(d) Delta and Estuary

Question 3.
Answer the following questions in about 30 words.

(a) What are the socio-economic advantages of inter-linking of rivers in India?
Answer:
The rivers of India carry huge volume of water approximately 2,124,3 7 cubic km. per year. But it is unevenly distributed both in time and space. One part has much water which is wasted in floods and one part of the country suffers from drought. To minimise this problem the surplus water is transferred to the deficit basin through inter-linking system.

(b) Write three characteristics of the Peninsular rivers.
Answer:
(i) Subsidence of the western flank of the Peninsula led to its submergence below the sea during the early tertiatry period. Generally, it has disturbed the symmetrical plan of the river on either side of the original watershed.

(ii) Upheaval of the Himalayas when the northern flank of the Peninsular block was subjected to subsidence and the consequent trough faulting. The Narmada and the Tapi flow in trough faults and fill the original cracks with their detritus materials. Hence, there is a lack of alluvial and deltaic deposits in these rivers.

(iii) Slight tilting of the Peninsular block from north-west to the south-eastern direction gave orientation to the entire drainage system towards the Bay of Bengal during the same period.

Question 4.
Answer the following questions in not more than 125 words.
(i) What are the important characteristic features of the north Indian rivers? How are these different from the peninsular rivers?
Answer:
The Brahmaputra, the Ganga and the Indus are the north Indian rivers. Gangarises in the Gangotri glacier in Uttrakashi district of Uttranchal. Uttar Pradesh, Bihar and West Bengal are other states drained by this river. The river finally discharges itself into the Bay of Bengal.

The Brahmaputra and the Indus originate on the southern slopes ofthe Tibetan highlands. These rivers run parallel to the axis of the Himalayas and take sudden turn towards the south cutting deep gorges in the mountain ranges to reach the great plain.

Important characteristics:

• North Indian rivers are perennial.
• Their regimes are dependent on the water supply from snow melt and rainfall.
• The catchment area of the north Indian river system is very large and extensive.
• The ‘Himalayan rivers flow into the deep gorges in the mountainous region and form meandering in the plains.

North Indian rivers are different from the peninsular river systems. The catchment area of the peninsular river systems is comparatively smatl and spreads over a limited area. These rivers are non-perennial. They are seasonal and rainfed. These rivers show little meandering and they have lesser erosional capacity.

(ii) Suppose you are travelling from Hardwar to Siliguri along the foothills of the Himalayas. Name the important rivers you will come across. Describe the characteristics of any one of them.
Answer:
Important rivers :

• Brahmaputra
• Siang or Dihang,
• Dibang or Sikang
• Lohit
• Subansiri
• Kameng
• Manas and Sankosh.

The Brahmaputra – The Brahmaputra system is an extensive and important river system of India. It spreads over 5,50,000 km² area. It has its origin in the trans-Himalayan glacier of the Kailash range near Mansarovar Lake. The river emerges from the foothills under the name ofSiangandthen Dihang. Itenters India west of Sadiya town in Arunachal Pradesh. Flowing south-west, it receives its main left bank tributaries viz. Dibang and Lohit.

The Brahmaputra receives numerous tributaries in its 750 km. long journey in the Assam valley. The major tributaries are Burhi Dihang, Dhansari and Kalang on left bank and Subansari, Manas and Sankosh on right bank. After traversing a total length of about 2900 km. in Tibet, India and Bangladesh, it finally discharges in the Bay of Bengal after merging with the Padma river in Bangladesh.

Flood is a characteristic feature of Brahmaputra. This is due to the fact that both Purvanchal (eastern) Himalayas and Shillong plateau receive heavy rainfall.

Detailed, Step-by-Step NCERT Solutions for Class 11 Geography Chapter 1 India: Location Questions and Answers were solved by Expert Teachers as per NCERT (CBSE) Book guidelines covering each topic in chapter to ensure complete preparation.

India: Location NCERT Solutions for Class 11 Geography Chapter 1

India: Location Questions and Answers Class 11 Geography Chapter 1

Question 1.
Choose the right answer from the four alternatives given below :
(i) Which one of the following latitudinal extent is relevant for the extent of India’s area?
(a) 8°41’N to 35°7’N
(b) 8°4’N to 3706’N
(c) 8°4’N to 35°6’N
(d) 6°45’N to 37°6’N
Answer:
(b) SMTM to

(ii) Which one of the following countries shares the longest land frontier with India?
(a) Bangladesh
(b) China
(c) Pakistan
(d) Myanmar
Answer:
(a) Bangladesh.

(iii) Which one of the following countries is larger in area than India?
(a) China
(b) Egypt
(c) France
(d) Iran
Answer:
(a) China.

(iv) Which one of the following longitudes is the standard meridian for India?
(a) 69°30’E
(b) 82°30’E
(c) 75°30’E
(d) 90°30’E
Answer:
(b) 82°30’E.

Question 2.
Answer the following questions in about 30 words :
(i) Does India need to have more than one standard time? If yes, why do you think so?
Answer:
No, India does not need to have more than one standard time because to maintain uniformity of time as far as possible within the country, all places should have a uniform time.

(ii) What are the implications of India having a long coastline?
Answer:
India has a coastline of 6,100 km in the main land and 7,517 km including the coast of the island groups lying in the Arabian Sea and Bay of Bengal. Sri Lanka and Maldives are the two neighbouring island countries in the Indian ocean.

(iii) How is the latitudinal spread of India advantageous to her?
Answer:
From the values of latitude, it is understood that the southern part of the country lies within the tropics and the northern part lies in the subtropical zone or the warm temperate zone. This location is responsible for large variations in land forms, climate, soil types and natural vegetation in the country.

(iv) While the sun rises earlier in the east, say Nagaland and also sets earlier, how do the watches at Kohima and New Delhi show the same time?
Answer:
While the sun rises in the northeastern states about two hours earlier as compared to Jaisalmer, the watches in Kohima and New Delhi show the same time. Because, India has a standard meridian 82°30′ east longitude which sets the Indian Standard Time (1ST) for the entire nation.

Question 3.
Answer the following questions in not more than 125 words.
(i) India plays a vital role in the Southeast Asian region. Give your view points to substantiate the statement.
Answer:
India lies in the Southcentral part of the continent of Asia. Peninsular part of India protrudes to the Indian ocean which is benefited in many ways. It has promoted its international trade by providing a link with countries of east, southeast, far east, Asia and South West and . West Asia. It favoured trade in southeast Asia.

India plays a vital role in today’s world order. Among SAARC (South Asian Association for Regional Co¬operation) Nations, India stands as the largest in terms of area and people.

India’s strategies in tennis of strengthening the nations economics base influenced the neighbouring countries. India has always bestowed its munificance upon the countries in case of any natural calamities. It shoulders responsibility of strengthening the South Asian economy through collective efforts.

Question 4.
Do you think that India’s peninsular location is beneficial to the country? Why do you think so?
Answer:
Peninsular part of India which protrudes to the Indian ocean for about 1,600 km has benefited it in many ways. It has promoted its international trade by providing a link with countries of East, South East, Far East, Asia and South West Asia. It earns a fair amount of its foreign exchange through her export of varied products and large number of people have their livelihood based on fishing owing to its long coastline.

The Indian climate is also greatly effected by its peninsular location. It has made the coastal areas a favoured place for living and also for the development of tourism. Number of tourist centres are located along the western and eastern coastal plains e.g. Kovalam beach, Juhu beach (Mumbai), Marina beach (Chennai), etc. Large number of tourists visit and enjoy the weather and scenic beauty of these coastal places.

Question 5.
What are the implications of the vast latitudinal extent of the country?
Answer:
The latitudinal extent of the country is vast. The Southern half of the country lies within the tropics and the northern half in the sub-tropical zone or the warm temperate zone. This location is responsible for the wide variety of rich flora and fauna.

This vast extent of latitude and ideal temperature conditions are beneficial to farmers. They grow a variety of crops such as rice, wheat, jawar, bajra, ragi, maize, pulses and fruits ranging from equatorial to temperate regions. They can cultivate two or three crops a year.

Detailed, Step-by-Step NCERT Solutions for Class 11 Geography Chapter 16 Biodiversity and Conversation Questions and Answers were solved by Expert Teachers as per NCERT (CBSE) Book guidelines covering each topic in chapter to ensure complete preparation.

Biodiversity and Conversation NCERT Solutions for Class 11 Geography Chapter 16

Biodiversity and Conversation Questions and Answers Class 11 Geography Chapter 16

Question 1.
Multipule Choice Questions :
(i) Conservation of biodiversity is important for ………….
(a) Animals
(b) Animals and plants
(c) Plants
(d) All organisms
Answer:
(d) All organisms.

(ii) Threatened species are those which
(a) threaten others
(b) Lion and Tiger
(c) are abundant in number
(d) are suffering from danger of extinction
Answer:
(d) are suffering from danger of extinction.

(iii) National parks and sanctuaries are established for the purpose of
(a) Recreation
(b) Hunting
(c) Pets
(d) Conservation
Answer:
(d) Conservation.

(iv) Biodiversity is richer in
(a) Tropical Regions
(b) Polar regions
(c) Temperat regions
(d) Oceans
Answer:
(a) Tropical regions.

(v) In which one of the following countries, the ‘Earth Summit’ was held?
(a) the UK
(b) Mexico
(c) Brazil
(d) China
Answer:
(c) Brazil.

Question 2.
Answer the following questions in about 30 words each :
(i) What is biodiversity?
Answer:
Biodiversity is a system in constant evolution, from a species as well as from an individual organism.

(ii) What are the different levels of biodiversity?
Answer:
Three levels of biodiversity are :

• Genetic biodiversity,
• Species diversity, and
• Ecosystem diversity.

(iii) What do you understand by ‘hot spots’?
Answer:
The diversity of species can be measured through its richness, abundance and types. Some areas are more rich in species than others. Areas rich in species diversity are called hot spots of diversity.

(iv) Discuss briefly the importance of animals to human kind,
Answer:
Animals helps in maintaining the ecosystem. They capture species and store energy, produce organic material to the ecosystem.

(v) What do you understand by ‘exotic species’?
Answer:
Species which are not the natural inhabitants of the local habitat but are introduced into the system, are called exotic species.

Question 3.
Answer the following questions in about 150 words each :

(i) What are the roles played by biodiversity in the shaping of nature?
Answer:
Biodiversity has contributed in many ways to the development of human culture and, in turn, human communities have played a major role in shaping the diversity of nature at the genetic, species and ecological levels. Biodiversity plays the following roles : ecological, economic and scientific.

Ecological role of biodiversity – Species capture and store energy,produce and decompose organic materials, help to cycle water and nutrients throughout the ecosystem, fix atmospheric gases and help regulate the climate. These functions are important for ecosystem function and human survival.

Economic role of biodiversity-For all humans, biodiversity is an important resource in their day-to-day life. One important part of biodiversity is ‘crop diversity’, which is also called agro-biodiversity.

Some of the important economic commodities that biodiversity supplies to humankind are : food crops, livestock, forestry, fish, medicinal resources, etc.

Scientific role of biodiversity – Biodiversity is important because each species can give us some clue as to how life evolved and will continue to evolve. Biodiversity also helps in understanding how life functions and the role of each species in sustaining.

(ii) What are the major factors that are responsible for the loss of biodiversity? What steps are needed to prevent them?
Answer:
The various factors responsible for the loss of biodiversity are :
(1) Growth in human population has increased the rate of consumption of natural resources. It has accelerated the loss of species and habitation in different parts of the world.

(2) Over-exploitation of resources and deforestation have become rampant to fulfill the needs of large population.

(3) Natural calamities such as earthquakes, floods, volcanic eruptions, forest fires, droughts, etc. cause damage to flora and fauna of the earth, bringing loss of biodiversity.

(4) Pesticides and other pollutants such as hydrocarbons and toxic heavy metals destroy the weak and sensitive species.

(5) Tigers, elephants, rhinoceros, crocodiles, minks and birds are hunted mercilessly by poachers for their horns, tusks and hides.

Preventive measure : The International Union of Conservation of Nature and Natural Resources (IUCN) has classified the threatened species of plants and animals into three categories for the purpose of their conservation :

• It includes those species which are in danger of extinction.
• Efforts should be made to preserve the species that are endangered.
• Prevention of extinction requires sound planning and management.
• Varieties of food crops, forage plants, timber trees, livestock, animals and their wild relatives should be preserved.
• Each country should identify habitats of wild relations and ensure their protection.
• Habitats where species feed, breed, nurse their young and rest should be safeguarded and protected.
•  International trade in wild plants and animals must be regulated.

Detailed, Step-by-Step NCERT Solutions for Class 11 Geography Chapter 15 Life on the Earth Questions and Answers were solved by Expert Teachers as per NCERT (CBSE) Book guidelines covering each topic in chapter to ensure complete preparation.

Life on the Earth NCERT Solutions for Class 11 Geography Chapter 15

Life on the Earth Questions and Answers Class 11 Geography Chapter 15

Question 1.
Multiple Choice Questions :
(i) Which one of the following is included in biosphere?
(a) only plants
(b) all living and non-living organisms
(c) only animals
(d) all living organisms
Answer:
(b) all living and non-living organisms.

(ii) Tropical grasslands are also known as ……………..
(a) the prairies
(b) the savannas
(c) the steppes
(d) none of the above
Answer:
(b) the savannas.

(iii) Oxygen combines with iron found in the rocks to form
(a) iron carbonate
(b) iron nitrites
(c) iron oxides
(d) iron sulphate
Answer:
(c) iron oxides.

(iv) During photosynthesis, carbon dioxide combines with water in the presence of sunlight to form
(a) protein
(b) amino acids
(c) carbohydrates
(d) vitamins
Answer:
(c) carbohydrates.

Question 2.
Answer the following questions in about 30 words each :
(i) What do you understand by the term ‘ecology’?
Answer:
Ecology is the study of the earth as a ‘household’ of plants, animals and micro-organisms. They all live together as interdependent components.

(ii) What is an ecological system? Identify the major types of ecosystems in the world.
Answer:
The interactions of a particular group of organisms with land, air and water (abiotic factors) within a particular habitat or habitats, resulting in clearly defined energy flows and material cycles on land, water, and air, are called ecological systems.

Ecosystems are of two major types – terrestrial and aquatic. Terrestrial ecosystem is further classified into biornes. The major biomes of the world are – forest, grassland, desert and tundra biornes.

Aquatic ecosytem can be classified as marine and freshwater ecosystems. Marine ecosystem includes oceans, coastal estuaries and coral reefs. Freshwater ecosystem includes lakes, ponds, streams, marshes and bogs.

(iii) What is a food chain? Give one example of a grazing food- chain identifying the various levels.
Answer:
The food relation representing a producer, a primary consumer, a secondary consumer and a decomposer is called a food chain. The four trophic levels of a food chain are the producers, the herbivores or the primary or first order consumers (e,g. cattle, deer and goat), the carnivores or the secondary or second order consumers (e.g. lion) and the decomposers (e.g bacteria).

(iv) What do you understand by the term ‘food web’? Give examples.
Answer:
Many simple food chains intermingle with each other to form a food web. For example, each organism may eat a variety of food derived from another organism and, in turn, may be eaten by’a number of organisms at a higher level of the food chain. The primary producers use the energy of the sun and provide it to consumers at higher level. But energy is lost during each upward step in the food chain.

(e) What is a biome?
Answer:
The largest natural regions which occur in distinct group „ communities, in areas having similar climatic conditions, are known as biomes.

The major biomes of the world are :

• Tropical rain forest
• Tropical savanna
• Mediterranean scrub forest
• Deciduous forest
• Grassland
• Desert
• Taiga
• Tundra

Question 3.
Answer the following questions in about 150 words each :
(i) What are bio-geochemical cycles? Explain how nitrogen is fixed in the atmosphere.
Answer:
Living organisms survive with the flows of energy, water and nutrients. The balance between chemical elements of atmosphere and hydrosphere is maintained by a cyclic passage through the tissues of plants and animals. The cycle starts by absorbing of the chemical . elements by the organism and returned back to air, water and soil through decomposition. These cycles are largely energized by solar insolation.

These cyclic movements of chemical elements of the biosphere between the organism and the environment are known as biogeo-chemical cycles.

Nitrogen cycle: Nitrogen is a major constituent of the atmosphere. It is also an essential constituent of different organic compounds. Only few organisms like soil bacteria and blue green algae are capable of utilizing it directly in its gaseous form. Generally, nitrogen is usable only after it is fixed. 90% of fixed nitrogen is biological. The principal source of free nitrogen is action of soil micro-organisms and associated

plant roots on atmospheric nitrogen. Nitrogen can also be fixed in the atmosphere by lightning and cosmic radiation. In the oceans, some marine aniamls can fix it. After atmospheric nitrogen has been fixed into an available form, green plants can assimilate it. Dead plants and animals, excreted nitrogenous wastes are converted into nitrates by the attachment of bacteria present in the soil. They convert nitrites into nitrates that can be used by the plants again.

(ii) What is an ecological balance? Discuss the important measures needed to prevent ecological imbalances.
Answer:
Ecological balance is a state of dynamic equilibrium within a community of organisms in a habitat or ecosystem. This balance occurs through competition and co-operation between the different organisms where populations remains stable, and the fact that some species depend on others for their food and sustenance.

Important preventive measures to prevent ecological imbalances :

• Efforts should be made to preserve the species that are endangered.
• Sound planning and management is required to prevent extinction.
• Each country should identify habitats of wild relations and ensure their protection.
• Habitats where species feed, breed, nurse their young and rest should be safeguarded and protected.
• Deforestation should be prevented.