2024
ENVIRONMENTAL EDUCATION
Full Marks: 40, Pass Marks: 12
The figures in the margin indicate full marks for the questions.
1. (a) Answer in short (any five): (1×5=5)
(i) Define genetic diversity.
Answer: Genetic diversity refers to the variety of genes within a species. It helps organisms adapt to environmental changes.
(ii) Write the full form of SDRF.
Answer: The full form of SDRF is State Disaster Response Fund.
(iii) What is a food chain?
Answer: A food chain shows how energy flows from one organism to another in an ecosystem. It starts with plants and ends with top predators.
(iv) Write the name of a National Park of Assam.
Answer: Kaziranga National Park is a famous national park in Assam.
(v) What is an ecosystem?
Answer: An ecosystem is a community of living organisms interacting with their environment, including plants, animals, and microorganisms.
(vi) Which day is observed as 'World Environment Day'?
Answer: World Environment Day is observed on 5th June every year.
(vii) What is the solid mantle of the Earth?
Answer: The solid mantle of the Earth is the layer between the crust and the core, made of hot, solid rock.
1. (b) Fill in the blanks (any three): (1×3=3)
(i) Ozone is found in _________ of the atmosphere.
Answer: Ozone is found in the stratosphere of the atmosphere.
(ii) Diarrhea is a ________ disease.
Answer: Diarrhea is a waterborne disease.
(iii) Loktak Lake is situated in _______.
Answer: Loktak Lake is situated in Manipur.
(iv) Frog is a _______ level consumer of the ecosystem.
Answer: Frog is a secondary level consumer of the ecosystem.
(v) Mandatory road signs are generally ________ shaped.
Answer: Mandatory road signs are generally circular shaped.
2. Write short accounts on (any five): (2×5=10)
(a) Food web
Answer: A food web is a complex network of interconnected food chains in an ecosystem. It shows how different plants and animals are linked through feeding relationships. Unlike a simple food chain, a food web provides stability to the ecosystem because organisms have multiple food sources. For example, in a forest, a deer may eat grass, and a tiger may eat the deer, but the tiger can also eat other small animals.
(b) Climate change
Answer: Climate change refers to long-term shifts in weather patterns due to natural and human activities. It is mainly caused by the increased emission of greenhouse gases like carbon dioxide and methane from industries, vehicles, and deforestation. The effects of climate change include rising global temperatures, melting glaciers, extreme weather events, and changes in rainfall patterns. It poses a threat to biodiversity, agriculture, and human health.
(c) Ecological pyramid
Answer: An ecological pyramid is a graphical representation of different trophic levels in an ecosystem. It shows the relationship between producers and consumers in terms of number, biomass, or energy. There are three types of ecological pyramids:
Pyramid of Number – Shows the number of organisms at each level.
Pyramid of Biomass – Represents the total living matter at each level.
Pyramid of Energy – Depicts energy flow, with maximum energy at the producer level and decreasing energy at higher levels.
(d) In situ conservation
Answer: In situ conservation is the method of protecting biodiversity in its natural habitat. This helps endangered species survive in their original environment without human interference. Examples include national parks, wildlife sanctuaries, biosphere reserves, and sacred groves. In India, famous conservation areas include Kaziranga National Park (for one-horned rhinoceros) and Gir National Park (for Asiatic lions).
(e) Soil pollution
Answer: Soil pollution occurs when harmful substances like chemicals, pesticides, industrial waste, and plastics contaminate the soil. It affects plant growth, reduces soil fertility, and leads to health problems in humans and animals. Major causes include excessive use of fertilizers, improper waste disposal, and deforestation. To prevent soil pollution, organic farming, waste recycling, and afforestation should be encouraged.
(f) Trophic level
Answer: A trophic level refers to each step in the food chain where organisms obtain energy. There are different trophic levels in an ecosystem:
Producers (1st level) – Plants that make their own food.
Primary Consumers (2nd level) – Herbivores like deer and rabbits.
Secondary Consumers (3rd level) – Carnivores like frogs and snakes.
Tertiary Consumers (4th level) – Top predators like tigers and eagles.
Each level receives energy from the level below, but energy decreases as it moves up.
(g) The Wildlife (Protection) Act, 1972
Answer: The Wildlife (Protection) Act, 1972, is an Indian law aimed at protecting wildlife and their habitats. It provides legal protection to endangered species and prohibits hunting and poaching. The act also allows the creation of national parks, wildlife sanctuaries, and biosphere reserves. It classifies animals into different schedules based on their level of protection. This law has helped in the conservation of species like the Bengal tiger and one-horned rhinoceros.
(h) Biodiversity of Assam
Answer: Assam is rich in biodiversity due to its varied climate, forests, and wetlands. It has several national parks and wildlife sanctuaries, such as Kaziranga National Park (home to the one-horned rhinoceros) and Manas National Park (a UNESCO World Heritage Site). Assam’s biodiversity includes elephants, tigers, leopards, golden langurs, and many species of birds and reptiles. The Brahmaputra River and its tributaries support diverse aquatic life, including the endangered Gangetic dolphin. Conservation efforts are essential to protect Assam’s unique wildlife.
3. Define and distinguish (any four): (1+2)×4=12
(a) Consumer and Decomposer
Definition:
Consumer: An organism that depends on other organisms for food.
Decomposer: An organism that breaks down dead plants and animals.
Distinction:
(b) Food Chain and Food Web
Definition:
Food Chain: A linear sequence of organisms where each one is eaten by the next.
Food Web: A complex network of interconnected food chains in an ecosystem.
Distinction:
(c) Pollutant and Pollution
Definition:
Pollutant: A harmful substance that causes pollution.
Pollution: The contamination of the environment by harmful substances.
Distinction:
(d) Atmosphere and Biosphere
Definition:
Atmosphere: The layer of gases surrounding the Earth.
Biosphere: The part of Earth where life exists, including land, water, and air.
Distinction:
(e) Seat Belt and Helmet
Definition:
Seat Belt: A safety strap in a vehicle to protect passengers during accidents.
Helmet: A protective headgear worn by motorcyclists and cyclists.
Distinction:
(f) Road Marking and Zebra Crossing
Definition:
Road Marking: Painted lines or symbols on roads to guide drivers.
Zebra Crossing: A marked pedestrian crossing with white and black stripes.
Distinction:
(g) Natural Disaster and Man-Made Disaster
Definition:
Natural Disaster: A disaster caused by natural forces like earthquakes or floods.
Man-Made Disaster: A disaster caused by human activities like pollution or accidents.
Distinction:
4. Answer the following questions (any two): (5×2=10)
(a) Describe the various causes of depletion of the ozone layer.
Answer: The ozone layer is a protective shield in the stratosphere that absorbs harmful ultraviolet (UV) radiation from the sun. The major causes of ozone layer depletion are:
Chlorofluorocarbons (CFCs): These are chemicals used in refrigerators, air conditioners, and aerosol sprays. When released into the atmosphere, CFCs break down ozone molecules.
Halons and Bromine Compounds: These are used in fire extinguishers and contribute to ozone destruction.
Nitrogen Oxides (NOx): Emitted from vehicles and industries, NOx reacts with ozone and reduces its concentration.
Volcanic Eruptions: Natural events like volcanic eruptions release gases that can affect the ozone layer.
Deforestation: Trees absorb carbon dioxide, and cutting them down increases greenhouse gases, indirectly affecting ozone recovery.
(b) Describe the various causes of air pollution.
Answer: Air pollution occurs when harmful substances mix with the air, affecting human health and the environment. The major causes are:
Vehicle Emissions: Cars, trucks, and buses release pollutants like carbon monoxide and nitrogen oxides.
Industrial Activities: Factories release smoke, chemicals, and toxic gases like sulfur dioxide and carbon dioxide.
Burning of Fossil Fuels: Coal, oil, and gas used in power plants and households contribute to air pollution.
Deforestation: Fewer trees mean less absorption of carbon dioxide, leading to higher pollution levels.
Agricultural Activities: Pesticides, fertilizers, and burning of crop residues release harmful gases like methane and ammonia.
(c) What do you mean by global warming? Mention two consequences of global warming.
Answer:
Global warming refers to the gradual increase in Earth's average temperature due to excessive greenhouse gases like carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O). These gases trap heat in the atmosphere, leading to climate change.
Two consequences of global warming:
Melting of Ice Caps and Rising Sea Levels: Increased temperatures cause glaciers and polar ice to melt, leading to floods and loss of land.
Extreme Weather Conditions: Global warming increases the frequency of heatwaves, droughts, hurricanes, and storms, causing destruction and loss of life.
l
(d) Write the role of students in disaster management.
Answer: Students play an important role in disaster management by spreading awareness and taking preventive measures. Their contributions include:
Spreading Awareness: Educating people about natural disasters, safety measures, and emergency preparedness.
Participating in Mock Drills: Schools and colleges conduct mock drills to train students on how to respond to emergencies.
Helping in Rescue Operations: Assisting authorities by guiding people to safe locations during disasters.
Volunteering in Relief Work: Distributing food, water, and medical aid to affected people.
Promoting Environmental Conservation: Encouraging afforestation and reducing pollution to minimize the impact of disasters like floods and climate change.
(e) Write about the major causes of deforestation in Northeast India.
Answer: Deforestation in Northeast India is a major environmental concern. The key causes are:
Jhum Cultivation (Shifting Cultivation): Farmers clear forested land for farming, leading to deforestation.
Timber Logging: Illegal and excessive cutting of trees for wood, furniture, and construction reduces forest cover.
Infrastructure Development: Roads, bridges, dams, and urban expansion lead to the destruction of forests.
Tea and Rubber Plantations: Large-scale plantations replace natural forests, affecting biodiversity.
Forest Fires: Both natural and human-made fires destroy vast areas of forest, leading to loss of vegetation and wildlife.
-0000-