Forests Our Lifeline — Class 7 Science NCERT Solutions (Free)
Free step-by-step NCERT solutions for Class 7 Science chapter "Forests Our Lifeline" — 8 important questions with detailed answers for CBSE board exam preparation.
TL;DR: Free step-by-step NCERT solutions for Class 7 Science chapter "Forests Our Lifeline" — 8 important questions with detailed answers for CBSE board exam…
By Syllab.in · Updated
Key Questions Covered:
- What is a forest? Define ecosystem.
- What are the layers of forest? Describe each.
- Explain the food chains and food webs in a forest.
- What is the role of decomposers in forest ecosystem?
- How do forests help prevent soil erosion?
- Discuss how forests affect the water cycle and climate.
- + 2 more questions in the full chapter
Solutions Summary:
| Question | Status |
|---|---|
| What is a forest? Define ecosystem. | ✓ Solved |
| What are the layers of forest? Describe each. | ✓ Solved |
| Explain the food chains and food webs in a forest. | ✓ Solved |
| What is the role of decomposers in forest ecosystem? | ✓ Solved |
| How do forests help prevent soil erosion? | ✓ Solved |
| Discuss how forests affect the water cycle and climate. | ✓ Solved |
Showing 6 of 8 questions
Q1: What is a forest? Define ecosystem.
Forest: large area of land covered with trees and other vegetation, supporting diverse flora and fauna. Forest ecosystem: community of living organisms (biotic) and their physical environment (abiotic) interacting together.
Biotic: trees, animals, plants, microorganisms. Abiotic: sunlight, water, soil, temperature, humidity. Forest provides: oxygen, water, timber, medicines, food, habitat for wildlife.
Q2: What are the layers of forest? Describe each.
Forest layers (from top to bottom):
1. Canopy: tall trees with thick foliage; intercepts most sunlight
2. Understory: shorter trees and shrubs; receives filtered light
3. Shrub layer: bushes and small plants
4. Herb layer: grasses, herbs, ferns; experiences low light
5. Forest floor: leaf litter, decomposing matter, soil organisms (bacteria, fungi); richest in organic matter
Each layer supports different plants and animals adapted to light and moisture conditions.
Q3: Explain the food chains and food webs in a forest.
Food chain: linear sequence of organisms transferring energy. Producer → Primary consumer → Secondary consumer → Tertiary consumer.
Example: Plant → Grasshopper → Frog → Snake → Eagle
Food web: interconnected food chains showing multiple feeding relationships in ecosystem.
Energy flow: Sun → Plants (producers) → Herbivores → Carnivores → Decomposers
Loss: only 10% energy transferred at each level due to respiration and body maintenance.
Q4: What is the role of decomposers in forest ecosystem?
Decomposers: bacteria, fungi that break down dead organisms and waste material. Roles:
1. Decomposition: break down dead plants, animals, waste into simpler substances
2. Nutrient cycling: release nutrients (nitrogen, phosphorus) back to soil
3. Soil enrichment: add organic matter, improve soil fertility
4. Energy release: release stored chemical energy from dead matter
5. Waste management: prevent accumulation of dead matter
Without decomposers, nutrients would be locked in dead organisms, depl...
Q5: How do forests help prevent soil erosion?
Forest role in soil conservation:
1. Root system: tree roots bind soil particles together, increase cohesion
2. Leaf litter: dead leaves and twigs cover soil, reduce water velocity
3. Canopy: dense foliage intercepts rainfall, reduces direct impact on soil
4. Water retention: porous humus-rich forest soil absorbs more water
5. Prevents landslides: root network anchors soil on slopes
6. Reduces runoff: slower water flow reduces surface erosion
Without forests, heavy rain washes away topsoil (fert...
Q6: Discuss how forests affect the water cycle and climate.
Forests and water cycle:
1. Evapotranspiration: plants release water vapor, increasing atmospheric humidity
2. Rainfall increase: vegetation enhances cloud formation and precipitation
3. Groundwater: forest canopy and litter allow more water infiltration into soil, recharging aquifers
4. Rivers: forests regulate water flow, prevent floods and droughts
Forests and climate:
1. Carbon sequestration: absorb CO₂, reduce greenhouse gases
2. Temperature regulation: large-scale evaporation cools atmosph...
Showing 6 of 8 questions. Visit the full page for complete solutions.
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