PrefaceWhy is this book important for your preparation?

There are several books in the market pertaining to the Ecology and Environment, but none of them deals with the current pattern of the examination. Hence, there is

an urgent need to cater to the requirements of the aspirants of lAS, State Public Services, as well as other competitive examinations.

This book has been designed keeping in mind the pattern of Civil Services examination. Since there is a major change in the pattern of the questions of different examinations, especially UPSC, this book serves as an elixir to the aspirants.

This material is very comprehensive and covers all aspects of Ecology and Environment alongwith the objective and subjective practice questions.

The content has been designed in point format and in lucid language covering length and breadth of each topic alongwith respective figures.

Thus this book will enable studentsto understand the finer points as well the multi-di-mensional perspective of the subject.

Last but not the least; I would like to thank my parents, who supported me with love and understanding, my committee members, each one of them has provided patient advice and guidance throughout the research process.

Suggestions for improvement in the book are welcome.

Best Wishes

Amrit Singh Chopra Chief Educator

Unique Shiksha

About the BookThought behind the Book

The ever-changing pattern of Civil Services Examination and the evolving needs of aspirants drove us to create a new series of reference books following a Unique Pattern.This has been designed to meet two basic needs of every Civil Services Aspirant:• ContentRetentionManagement(Understanding of basic concepts and retention of facts); and• TimeManagement(saving time by avoiding reading from different sources).

Pedagogical Assistance to be Found in the Book

This book covers – EcologyandEnvironmentcomprehensively. The team comprising of the author, editors and publishing experts have followed the below mentioned concepts to ensure this book meets requirements like no other.

Salient features are:• Each chapter is broken into units to signify how much content an aspirant must cover daily.• The topic mainly covers the fundamental concepts, but it includes many underlined concepts

and inter-linkages which are dynamic in nature because due to speedy economic development many environmental issues are coming up. Hence all topics and key points are broken down into bullet points to help with lucid and concise learning.

• The material is suitable for both the Prelims and Main examination. • Every unit ends with Prelims and Mains oriented questions to ensure that the aspirants test

themselves on what they have studied to ensure clarity of concepts.

How this book is One-Stop reference

• The book is the amalgamationofdifferentsources,editedbyexpertsto provide one stop solution for EcologyandEnvironment.

• The content has been designed by taking assistance of NCERT,NIOSandotherstandardbooks.Further deepanalysisofpreviousyearpapershave also been done to add more relevant topics.

• Hence it will act as a completeself-studymaterial.

UNIQUE SHIKSHA MASTER SERIES vs. Other Books

Specifications MASTERSERIES OTHERBOOKSStandard content referred from different Sources Yes Yes

Crisp and Concise concept with indepth analysis Yes No

Practice Questions Yes No

Pictorial representation of content for easy retention Yes No

Trend Analysis of Ecology and Environment

In Prelims examination• Ecology and Environment forms an important part of the Civil Services Examination. The

weightage of questions asked in Prelims are generally 15-18• Accordingtothetrend,thequestionsrelatedtoEcologyandEnvironmentaskedintheUPSC

IASprelimsexamweremoderatetotoughintheirdifficultylevel.• QuestionsfromtheEnvironmentsectionwereaskedbasedoncurrentaffairsmainlybasedon

the underlined environment issues.

Year No. of questions

2018 13

2017 15

2016 18

2015 11

2014 18

• If we analyse the previous year questions, certain sub-sections are frequently asked in the paper such as – sustainable agricultural practices, locations of national parks, species in news, climate change and policies associated with it.

In Main examination• UPSC Syllabus mentions about Ecology and Environment as - Conservation, environmental

pollution and degradation, environmental impact assessment.• It demands not only basic understanding of these topics, but also critical and analytical abilities

to answer questions on these topics. The content has been designed in detail to develop analytical and multi-dimensional approach of the student.

Year No. of questions

2018 45

2017 25

2016 25

2015 25

2014 25

2013 45

• The questions are mainly based on current issues but basic understanding of concepts is must. This book helps student in enhancing concept clarity, however, dynamic issues are also covered.

ImportantNotes: 1. A student should focus on understanding the chronology of events for retaining the facts

in the history. He/Sheshouldreadeachchapterminutely,jotdowntheimportantpoints as designing Self study notes are very important for the revision.

2. TheTopicsandsub-topicsrelatedtoPreviousYearQuestionshavebeencateredin the book.

What makes this book special?

Day-wise self study plan to achieve reasonable targets with respect to different demensions

of the subject.

Ecology & ENVIRONMENT

ECOLOGY AND ENVIRONMENT MASTER SERIES

UNIT 1

Levels of Organization of Life ● Organisms : The individuals of a species

(Living things) ● Population : Individuals of the same

species at a given place. (In an eco system)

Bullet format material for easy reading and high retention

of facts

MCQs for Preliminary Examination1. Which of the below factors affect the envi-

ronmental system of the planet Earth? 1. Biotic and abiotic factors 2. Revolution of the Earth 3. Rotation of the Earth 4. Habitats Choose the correct answer using the codes

given below: (a) 1 and 4 only (b) 1 only (c) 2 and 3 only (d) All of the above

Chapter end prelims questions for immediate practice and

progressive learning.

Chapter end Subjective questions for enhancing the Art

of Answer Writing

Subjective type questions for Main Examination

1. What do you mean by the term ‘keystone’ species? How is it beneficial in maintaining the biodiversity in a given region. Explain with examples.

How a Unique Shiksha foundation student should use this Book?

• ChaptersandContentareinsyncwiththeclasstohelpinachievingdesireddailyprogress.Thus student can use the material for daily revision and practicing of questions.

• ClassTestsaredrawnfromthebooktotestastudentforprogressivelearning.• Thesubjectivetypequestionscanbegivenforcheckingtoteachersonceinawhile,thismay

help in improving Answer Writing Skill.

ContentsUnit 1: Ecology and Environment 1-7

1.1. What is Ecology and Environment1.2. Levels of Organisation of Life1.3. Factors effecting Environment1.4. Major Biomes of the World

1.4.1 Tundra Biome1.4.2 Coniferous Forests1.4.3 Temperate Forests1.4.4 Grasslands1.4.5 Tropical Forests1.4.6 Deserts

1.5. Population Ecology

Unit 2: Population Interactions 8-142.1 Positive Interactions2.2 Negative interactions2.3 Energy flow in the ecosystem3.4 Trophic Level2.5 Food Chain and Food Web2.6 Ecological Pyramids

Unit 3: Ecosystems 15-303.1 Ecology and Ecosystem basics3.2 Terrestrial and Aquatic Ecosystem3.3 Components of Ecosystem3.4 Functions of Ecosystem3.5 Productivity and Decomposition3.6 Ecological Succession3.7 Biogeochemical cycles

3.7.1 Carbon Cycle3.7.2 Oxygen Cycle3.7.3 Nitrogen Cycle3.7.4 Phosphorus Cycle3.7.5 Sulphur Cycle

3.8. Aquatic ecosystem3.8.1 Wetland ecosystem3.8.2 Lake Ecosystem3.8.3 Estuary3.8.4 Mangroves3.8.5 Coral Reefs and Coral Bleaching

3.9 Ramsar Convention

Unit 4: Biodiversity 31-464.1 Introduction4.2 Types of Biodiversity4.3 Importance of Biodiversity4.4 Threats of Biodiversity4.5 Biodiversity Conservation

4.5.1 In-Situ Conservation4.5.2 Ex-Situ Conservation

4.6 Biodiversity of India4.7 Global Initiatives to protect Biosphere

4.7.1 Biosphere Reserves4.7.2 Biodiversity hotspots4.7.3 World Heritage Sites

4.8 Indian Conservation efforts4.8.1 Project Tiger4.8.2 Project Elephant4.8.3 Ganges Dolphin4.8.4 Vulture Protection 4.8.5 One Horned Rhino Project4.8.6 Project Hangul4.8.7 Snow Leopard4.8.8 Sea turtle Project

Unit 5: Climate Change 47-585.1 Introduction5.2 Natural factors leading to Climate Change5.3 Anthropogenic factors leading to Climate Change5.4 Impact of Climate Change on Health, Environment and Economy5.5 Mitigation strategies5.6 Ozone Depletion5.7 Deforestation5.8 Global Warming Potential5.9 India and Climate Change Initiatives

Unit 6: Environmental Organisations and Institutions 59-646.1 Animal Welfare Board6.2 Central Zoo Authority6.3 National Biodiversity Authority6.4 Wildlife Crime Control Bureau6.5 National Ganga River Basin Authority6.6 National Green Tribunal6.7 Central Pollution Control Board6.8 Genetic Engineering Approval Committee

Unit 7: Global Environmental Governance 65-727.1 Climate Change Governance

7.1.1 UNFCCC7.1.2 Kyoto Protocol7.1.3 Conference of Parties7.1.4 REDD and REDD+7.1.5 IPCC7.1.6 Kigali Agreement

Unit 8: Environmental Acts and Policies 73-928.1 National Acts and Policies

8.1.1 Wildlife Protection Act8.1.2 Environment Protection Act8.1.3 National Forest Policy8.1.4 Biological Diversity Act, 20028.1.5 Scheduled Tribes and other Forest Dweller Act8.1.6 Coastal Regulation Zone8.1.7 Wetland Rules8.1.8 Compensatory Afforestation Fund Management and Planning Authority

8.2 International Environmental Conventions8.2.1 United Nations conference on Environment and Development8.2.2 Convention on Biological Diversity8.2.3 Agenda 218.2.4 Ramsar Convention8.2.5 CITES8.2.6 TRAFFIC8.2.7 UNFF8.2.8 IUCN8.2.9 Stockholm convention8.2.10 Basel Convention8.2.11 Rotterdam Convention8.2.12 Vienna Convention8.2.13 Montreal Protocol

8.3 Environmental Impact Assessment8.4 Tiger Reserves in India8.5 Elephant Reserves in India8.6 Biosphere Reserves in India

Unit 9: Environmental Issues 93-1039.1 Air Pollution and its impact9.2 Water Pollution and its impact9.3 Noise pollution9.4 E-Waste

9.5 Thermal Pollution9.6 Plastic Pollution

Unit 10: Current Affairs 104-11510.1 BIOFIN10.2 Secure Himalayan Project10.3 National Wildlife Action Plan 2017-3110.4 Project ‘Blue Flag’10.5 Foundation for Environmental Education10.6 International Conference on Sustainbale Biofuels10.7 UN Emission Gap Report, 201710.8 Scheme for protection of Majuli Island10.9 India State of Forest Report, 201710.10 Solid Waste and its control10.11 Radioactive Wastes10.12 Bioremediation10.13 International Solar Alliance10.14 Biofuels

Ecology & Environment

Introduction to Constitution & Preamble | 1

● Communities : It is the assembly of population of all different species living in an area and interacting.(In an eco system)

● Biomes : These are relatively large regional units of flora and fauna in a specific climatic zone

Factors affecting the environment

1. Rotation of earth 2. Seasonal and annual variation in temperature

and precipitation 3. Habitats 4. Both biotic and abiotic factors.

Ecology & EnvironmentWhat is Ecology It is the branch of Biology which deals with relationship between organisms and their physical and biological environment.The word ‘ecology’ has been derived from the greek word “oikos” meaning home & “logos” meaning study. This term was given by Ernst Haeckel in 1869.What is Environment Sum of all biotic and abiotic factors that surround and influence an organism in its survival and reproduction constitute the environment. (The immediate surroundings of an organism).

Levels of Organization of Life ● Organisms : The individuals of a species

(Living things) ● Population : Individuals of the same

species at a given place. (In an eco system)

Ecology & ENVIRONMENT

Major Biomes of the World

Tundra Biome ● Lies roughly beyound 65°N. ● It is the most continuous of all biomes. ● It is an extremely fragile biome as it lacks

diversity. ● Temperature: The tundra biome is

characterized by a very low temperature and its warmest month is June. Winters are long and severe; summers are cool and brief. There are three types of tundra: arctic tundra, alpine tundra and Antarctic tundra.

● Precipitation: Precipitation is mainly in the form of snow, falling in winter. In summers, the precipitation is in the form of rain. The rainfall is not more than 25cms a year.

● Flora and Fauna: The greatest inhibiting factor is the deficiency of heat. The drainage system is also poor. So, there are no trees in the tundra. Mosses, lichens, rhododendrons, junipers, alders and sedges are the commonly found vegetation here. Animals of tundra are musk ox, reindeer, squirrel and lemmings.

ECOLOGY AND ENVIRONMENT MASTER SERIES

UNIT 1

2 Master Series : Ecology and Environment

● Distribution: It is found in northernmost parts of Canada, Alaska, Siberia, Iceland, Greenland and northern Scandinavia. It is the most continuous of all biomes and the coldest too. It is an extremely fragile biome as it lacks diversity. This biome is characterized by “Permafrost”; permanently frozen sub-soil portion.

Coniferous ForestsBetween the tundra to the north and the deciduous forest to the south lies the large area of coniferous forests.

● One type of coniferous forests, the northern boreal forest, is found betweem 50° to 60°N latitudes. An another type, temperate coniferous forests, grows in lower latitudes of North America, Europe, and Asia, in the high elevations of mountains.

● Coniferous forests consist mostly of conifers, trees that grow needles instead of leaves – and cones instead of flowers. Conifers tend to be evergreen, that is, they bear needles all the year long. Some of the more common conifers are spruces, pines, and firs.

Characteristics of Coniferous forestsSpecies: (Coniferous forest) Pine, Fir, Hemlock, Larch, Cedar (softwood trees). Coniferous forest regions have cold, long, snowy winters, and warm, humid summers; well-defined seasons, and have at least four to six frost-free months.Temperature: –40°C to 20°C, average summer temperature is 10°C.Precipitation: 300 to 900 millimeters of rain in a year.Vegetation: (25–100 cm) Coniferous-evergreen trees (trees which produce cones and needles; some needles remain on the trees all year long)Location: Canada, Europe, Asia, United States, Russia.

Temperate Forests ● Temperate forests are found in areas with high

levels of precipitation, humidity and contain a variety of deciduous trees. Deciduous trees lose their leaves in the winter season.

● Temperate forests have a wide range of temperatures that correlate with its distinctive seasons.

● Temperate forests receive abundant amounts of precipitation in a year. The precipitation is in the form of rain and snow.

Characteristics of Temperate forestsTemperature: Temperatures range from hot in the summer with highs of 86 degrees F, to extremely cold in the winter with lows of - 22 degrees F.Precipitation: 20-60 inches of precipitation annually.Vegetation: Due to abundant rainfall and thick soil humus, temperate forests are able to support a wide variety of plant life and vegetation. Vegetation ranges from Maple trees, Walnut trees, Birch trees to Lichens and Mosses.Location: Eastern Asia, Central and Western Europe, Eastern United States.

Grasslands ● Grasslands are generally open and continuous,

fairly flat areas of grass. They are often located between temperate forests at high latitudes and deserts of subtropical latitudes.

● Grasses vary in size from 7 ft tall with roots extending down into the soil 6 ft to the short grasses growing to a height of only 8 to 10 inches tall.

● They are classified into ‘Tropical Grasslands’ (Savannah) & ‘Temperate Grasslands’

● Sannahas have two distinct seasons; rainy season in summers & dry winters.

● Fires are an important part of Savannahas; which make way for new growth.

● Savannah type Grasslands are found in Africa, Australia, America, India and Nepal.

● Temperate grasslands have cold winters and warm summers with some scanty rainfall.

● The grasses die back to their roots annually and the soil and the sod protect the roots and the new buds from the cold climate winter and dry conditions.

● The soil of temperate grasslands is deep and dark with fertile environment. People graze

Ecology & Environment 3

their livestock here and also grow wheat & other crops.

● A few trees may be found in this biome along the streams, but not many due to the lack of adequate rainfall.

● Grasslands are also called as prairies (USA), pampas (In Argentina), steppes (Russia), and savannas (In Africa), Pustaz (Hungary), Velds (South Africa)

There are two seasons in the temperate grassland. The growing season, and the dormant season. Plants do not grow during the dormant season because the climate is too cold at that time.

Characteristics of GrasslandsTemperature: Dependent on latitude, yearly range can be between -20°C to 30°C.Precipitation: About 500 to 900 mm of rain per year.Vegetation: Grasses, prairie clover, salvia, oats, wheat, barley, coneflowers etc.Location: The prairies of the Great Plains of North America, the pampas of South America, the veld of South Africa, the steppes of Central Eurasia, and surrounding the deserts in Australia (Found on every continent except Antarctica).

Tropical Forests ● Tropical rainforests are defined by the fact

that they are hot and wet, typical of the tropical climates.

● These forests are found near the equator where it is warm, these regions have rainfall the year-round, with little to no dry seasons.

● The climate of tropical rainforest biome is perfect for plant and animals growth, both.

● The hot and humid conditions of tropics create an ideal environment for the growth of bacteria and other microorganisms.

● The tropical forests cover about 6% of the Earth‘s surface, and are found all over the world but mostly in South America in Brazil.

● Even though they cover small percentage of land on Earth, they are home to the largest number of plant and animal species in a highly concentrated pockets.

Characteristics of Tropical RainforestsTemperature: Tropical rainforests are warm and humid. The temperature ranges from 21 to 30 degrees Celsius (70 to 85°F).Precipitation: Tropical rainforests receive annual precipitation of almost 60 to 160 inches (152 to 406 cm).Vegetation: It is assumed that tropical rainforests are home to a staggering 15 million different species of plants and animals, making them some of the world’s most diverse locations of species.Location: The world’s largest tropical rainforests are in Amazon basin in South America, lowland regions in Africa, and the islands off of Southeast Asia. While they are found in abundance in Sumatra and New Guinea, small areas are also found in Central America and parts of Australia.

DesertsDesert biomes are the driest of all the biomes. In fact, the most important characteristic of a desert is that it receives very little or no rainfall.

● Desert conditions are so severe; the plants that live there need to have adaptations to compensate for the lack of water.

● Some plants, such as cacti, store water in their stems and use it very slowly, while others like bushes conserve water by growing few leaves or by having large root systems to gather water or just have a few leaves.

● Some desert plant species have a short life cycle of a few weeks that lasts only during the periods of rain.

Characteristics of Desert BiomesTemperature: Average of 38°C during daytime, and average of –3.9°C at night.Precipitation: About 250 mm of rain per year.Vegetation: Cacti, small bushes, short grasses.Location: Between 15° and 35° latitude (North and South of the equator); examples are Mojave, Sonoran , Chihuahua, and Great Basin (North America); Sahara (Africa); Negev (Middle East); and Gobi (Asia).

4 Master Series : Ecology and Environment

Variation in HabitatsKey elements that lead to so much variation in the physical and chemical conditions of different habitats, areTemperature Ecologically, it is the most important factor. It decreases progressively from equator towards poles and from plains to mountain tops, Organisms survive only in suitable range of temperature.Water Life on earth originated in water. Productivity and distribution of plants this depends on water, solely. Water has significant effect on vegetation type and plays a major role in temperature modification & rainfall distribution.Light Sunlight is the source of energy- photosynthesis; Small plants (canopied by tall plants) are adapted to photosynthesize at low light conditions. Flowering is dependent on sunlight; Foraging, Reproductive and migratory activities of animals depend upon seasonal variation in light intensity; UV component – harmful to organisms.Soil Nature of Soil depends on – climate, weathering process, sedimentary or transported soil. Soil provides water, nutrients & anchorage to the plants.

Population EcologyPopulation ecology is the field of ecology that focuses on the factors that affect the population size of a given organism, population growth rate, and spatial dispersion of individuals with populations.

● Demography is the subset of population ecology that studies statistics related to human populations.

Factors Affecting Population Size ● The only factors that can alter population

sizes are births, deaths, immigration, and emigration.

● Births and immigration add individuals to a population whereas deaths and emigration remove individuals from a population.

● When more individuals are being added to a population than are being removed, the population increases in size.

● When more individuals are removed from the population than are added to the population, the population decreases in size.

● Population sizes do not change when the rate that individuals are lost from a population is equal to the rate that individuals are added to the population (dynamic equilibrium).

Factors affecting Population Growth Rates

● Population growth rates are affected by interactions with both the abiotic and biotic environment.

● Climatic factors such as precipitation and temperature can have profound direct and indirect effects on population sizes.

● Temporal fluctuations in abiotic conditions can be important causes of variation in population sizes.

● Biotic factors such as competition and predation can directly and indirectly affect population sizes.

● Population dynamics can be influenced by interactions with members of their own species (e.g., intra-specific competition) and members of different species (e.g.: inter-specific competition, predation, and mutualism).

Models of Population Growth

Fig. 1.1. Models of Population Growth

Population ecologists have developed mathematical models to study the growth of populations.

Ecology & Environment 5

● The simplest model of population growth is the exponential growth model which assumes that the per capita growth rate (the change in population size/time/individual) is constant. (Ref. Fig 1.1)

● Because populations growing exponentially continue to grow at an increasing rate, the exponential growth model is not a realistic model for most populations.

• The logistic growth model is a more realistic model because it allows the per capita growth rate to vary with population size.

• The carrying capacity, the population size at which the population growth rate equals zero, is reached when the per capita birth rate (# births/time/individual) equals the per capita death rate (# deaths/time/individual).

• In logistic growth, birth and death rates are density dependent; as populations increase in size the per capita birth rate decreases (due to increased competition for resources) and the per capita death rate increases due to increased competition for resources, the increased spread of disease or an increase in predation that arises when predators are attracted to areas of high population sizes.

In the real world patterns of population growth may be more complicated than predicted by simple models because most populations are regulated by a variety of density dependent (e.g., competition and spread of disease) and density independent factors (e.g., climate and disturbances).

Some Important DefinitionsEnvironment: It is surroundings or conditions in which an organism lives or operates.

Habitat: A habitat is where an organism lives i.e. where it obtains its food and shelter, and where it reproduces.Population: The (total) number of individuals of a particular species in a defined habitat (or given area).Community: A community is made up of all the plants and animals living in a habitat.Ecosystem: The community of organisms in a habitat, plus the non-living part of the environment (air, water, soil, light etc.) make up an ecosystem.Abiotic: Characterized by physical and chemical factors – i.e. temperature, rainfall, pressure, pH. (non living components)Biotic: All living organisms, which interact with each other.Ecological Niche: It is the role & position a species has in its environment. A species’ niche includes all of its interactions with the biotic & abiotic factors of its environment.Keystone Species: In many communities one or a few species appear to be very important in maintaining the community structure, these are called “Keystone”.Ecotone: Each community has its spatial limits. Sometimes the boundary between two communities may be very sharp (such as that between a forest and a lake) or gradual (as between a forest and grassland). This transitional zone or junction zone between two or more diverse communities is called ecotone.Edge Effect: In ecology, edge effect refers to the changes in population or community structures that occur at the boundary of two habitats. Areas with small habitat fragments exhibit especially pronounced edge effects that may extend throughout the range. As the edge effects increase, the boundary habitat allows for the greater biodiversity.

Cont..

6 Master Series : Ecology and Environment

MCQs for Preliminary Examination1. Which of the below factors affect the

environmental system of the planet Earth? 1. Biotic and abiotic factors 2. Revolution of the Earth 3. Rotation of the Earth 4. Habitats Choose the correct answer using the codes given

below: (a) 1 and 4 only (b) 1 only (c) 2 and 3 only (d) All of the above2. Consider the following characteristics: 1. Extremely cold climate 2. High biotic diversity 3. Simple vegetation structure 4. Short season of growth and reproduction Which of the above characteristics characterize

the Tundra Biome? Choose the correct answer using the codes below.

(a) 1, 2, 3 and 4 (b) 1, 2 and 3 only (c) 1, 3 and 4 only (d) 2, 3 and 4 only3. Which of the following grasslands are correctly

matched with the regions of their occurrence? 1. Pustaz-Hungary 2. Campos-Venezuela 3. Llanos-Brazil 4. Pampas-United States Choose the correct answer using the codes given

below: (a) 1 only (b) 4 only

(c) 1 and 3 only

(d) 2, 3 and 4 only

4. Consider the following regions of the world.

1. Mojave

2. Sonoran

3. Chihuahua

4. Negev

Choose the correct biome represented by the regions given above.

(a) Tropical rainforest

(b) Desert

(c) Tropical deciduous forest

(d) Boreal forest

5. Which of the following statements are incorrect about Temperate climate?

(a) The range of temperature is very high.

(b) It is very prominent climate in regions between 30o - 45o latitudes.

(c) Vegetation includes Walnut trees, Maple trees etc.

(d) The precipitation is in the form of rain only.

6. Which of the following causal factors are responsible for change in population of a region?

1. Birth

2. Immigration

3. Disease

4. Emigration

Choose the correct answer using the codes given below:

(a) 1 and 3 only

(b) 2 and 4 only

(c) All of the above

(d) 1, 2 and 4 only

Ecology and Environment Master Exercise 1

Ecology & Environment 7

Subjective type questions for Main Examination

1. What do you mean by the term ‘keystone’ species? How is it beneficial in maintainingthe biodiversity in a given region. Explain with examples.

2. Discuss the different factors that affect the population size and the population growth rates of India. Suggest measures to control the same.

4. What are the factors that make ‘Tropical rainforests, one of the most diverse biomes in the world? Also mention the places of their occurrence.

5. What do you mean by the term ‘Biome’? Discuss briefly different types of biomes on the earthwith examples.

Answers to MCQs1. (d) 2. (c) 3. (a) 4. (b) 5. (d) 6. (d)