Nature maintains a delicate balance where all living and non-living components interact harmoniously. Understanding ecosystems, food chains, food webs, and conservation helps us protect biodiversity and sustain life on Earth.
2. Ecosystem
Definition: A community of living organisms (biotic components) interacting with their **non-living environment (abiotic components)
An ecosystem is: a) Only plants in an area b) Community of organisms interacting with their environment c) Only animals in an area d) Only soil and water Answer: b
Biotic components of an ecosystem include: a) Sunlight and water b) Soil and air c) Plants and animals d) Temperature and humidity Answer: c
Abiotic components include: a) Bacteria b) Sunlight, soil, air, water c) Herbivores d) Decomposers Answer: b
Forest ecosystem includes: a) Trees, animals, soil, sunlight b) Only trees c) Only animals d) Only soil and water Answer: a
Pond ecosystem includes: a) Fish, water plants, insects, sunlight b) Only fish c) Only plants d) Only water Answer: a
Food Chains & Food Webs
Food chain shows: a) Flow of water b) Flow of energy from one organism to another c) Flow of sunlight d) Flow of soil nutrients only Answer: b
Food web is: a) Single food chain b) Interconnected food chains c) Only producers d) Only herbivores Answer: b
Producer in a food chain is: a) Herbivore b) Plant c) Carnivore d) Decomposer Answer: b
Primary consumers are: a) Carnivores b) Herbivores c) Omnivores d) Decomposers Answer: b
Secondary consumers are: a) Herbivores b) Plants c) Carnivores eating herbivores d) Decomposers Answer: c
Tertiary consumers are: a) Top predators b) Herbivores c) Plants d) Decomposers Answer: a
Decomposers: a) Eat other animals b) Make their own food c) Break down dead material d) None of the above Answer: c
Example of food chain: a) Grass → Grasshopper → Frog → Snake → Hawk b) Sun → Moon → Stars c) Soil → Water → Plants d) Air → Plants → Sun Answer: a
Energy in ecosystem flows from: a) Decomposers → Consumers → Producers b) Sun → Producers → Consumers → Decomposers c) Consumers → Sun → Producers d) Producers → Sun → Consumers Answer: b
Which is NOT a trophic level? a) Producer b) Primary consumer c) Abiotic factor d) Tertiary consumer Answer: c
Interdependence
Organisms depend on each other for: a) Food b) Shelter c) Oxygen d) All of the above Answer: d
Plants depend on animals for: a) Carbon dioxide b) Oxygen c) Sunlight d) Soil Answer: a
Animals depend on plants for: a) Oxygen b) Food c) Shelter d) All of the above Answer: b
Predators help maintain: a) Plant population b) Herbivore population c) Soil nutrients d) Air quality Answer: b
Decomposers recycle: a) Water b) Nutrients to soil c) Sunlight d) Oxygen Answer: b
Biodiversity & Balance
Biodiversity refers to: a) Number of plants only b) Variety of species in an ecosystem c) Number of animals only d) Soil quality Answer: b
High biodiversity helps: a) Ecosystem stability b) Food scarcity c) Pollution increase d) Soil erosion Answer: a
Loss of one species can: a) Affect entire ecosystem b) Have no effect c) Only affect soil d) Only affect sunlight Answer: a
Natural predators help: a) Reduce herbivore overpopulation b) Reduce plants c) Increase soil erosion d) Reduce sunlight Answer: a
Example of ecosystem balance: a) Plants produce oxygen → Animals breathe → Animals produce CO₂ → Plants use CO₂ b) Plants disappear → Animals survive c) Herbivores overeat → Plants thrive d) Decomposers stop working → Soil enriched Answer: a
Human Impact
Deforestation causes: a) Soil erosion b) Loss of habitat c) Climate change d) All of the above Answer: d
Pollution affects: a) Air b) Water c) Soil d) All of the above Answer: d
Overhunting reduces: a) Biodiversity b) Air quality c) Water availability d) Soil nutrients Answer: a
Introduction of exotic species can: a) Restore balance b) Disrupt native species c) Reduce sunlight d) Increase soil fertility Answer: b
Conserving nature includes: a) Planting trees b) Protecting endangered species c) Reducing pollution d) All of the above Answer: d
Conservation Methods
Renewable resources include: a) Solar energy b) Fossil fuels c) Coal d) Petroleum Answer: a
Protecting forests helps: a) Maintain biodiversity b) Increase deforestation c) Reduce water d) Reduce sunlight Answer: a
Decomposers include: a) Fungi and bacteria b) Lions and tigers c) Birds d) Insects only Answer: a
Crop rotation helps: a) Reduce soil nutrients b) Maintain soil fertility c) Increase pests d) Reduce biodiversity Answer: b
Conserving wetlands protects: a) Water birds b) Plants c) Fish d) All of the above Answer: d
Food Web and Chains – Advanced
Interconnected food chains form: a) Food pyramid b) Food web c) Ecosystem d) Trophic cycle Answer: b
Grass → Rabbit → Fox → Eagle shows: a) Energy flow b) Matter cycle c) Water cycle d) Carbon cycle Answer: a
Herbivores eat: a) Carnivores b) Producers c) Decomposers d) Omnivores Answer: b
Carnivores eat: a) Plants b) Herbivores c) Decomposers d) Producers Answer: b
Omnivores eat: a) Plants only b) Animals only c) Both plants and animals d) Decomposers only Answer: c
True/False
Abiotic factors include sunlight and water. True
Food chains show energy flow, not matter recycling. True
Predators are unnecessary in an ecosystem. False
Human activities can disrupt ecosystem balance. True
Decomposers recycle nutrients back to soil. True
Fill in the Blanks
Energy in ecosystem flows from Sun → Producers → Consumers → Decomposers.
Predators control herbivore population.
Biodiversity helps maintain ecosystem stability.
Overhunting reduces species diversity.
Conservation of nature includes reducing pollution and protecting habitats.