Class 8 Science Chapter 12 How Nature Works in Harmony Solutions | Curiosity NCERT Answers

🌟 Class 8 Science – Curiosity Chapter 12

🌿 How Nature Works in Harmony

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🟢 1. Refer to the given diagram (Fig. 12.19) and select the wrong statement.

(i) A community is larger than a population.

(ii) A community is smaller than an ecosystem.

(iii) An ecosystem is part of a community.

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❌ Answer:

👉 (iii) An ecosystem is part of a community

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🧠 Explanation:

🌱 Population (जनसंख्या):

👉 Same species in an area

🌿 Community (समुदाय):

👉 Many populations together

🌍 Ecosystem (पारिस्थितिकी तंत्र):

👉 Community + non-living factors (air, water, soil)

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📊 Relationship:

Population < Community < Ecosystem ✔️

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📌 Conclusion:

• (i) ✔️ Correct
• (ii) ✔️ Correct
• (iii) ❌ Wrong (because ecosystem is larger, not part of community)

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🟢 2. A population is part of a community. If all decomposers suddenly disappear from a forest ecosystem, what changes do you think would occur? Explain why decomposers are essential.

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✅ Answer:

🧠 If decomposers disappear:

• 🍂 Dead plants and animals will accumulate
• ♻️ Nutrients will not return to soil
• 🌱 Soil fertility will decrease
• 🌍 Entire ecosystem balance will be disturbed

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📌 Importance of Decomposers:

• 🔄 Recycle nutrients (पोषक तत्व)
• 🌱 Maintain soil fertility
• ♻️ Keep natural cycles running

👉 Conclusion: Decomposers are essential for ecosystem balance ✔️

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🟢 Class 8 Science Curiosity Chapter 12 Question 3 and 4

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🟢 3. Selvam from Cuddalore district, Tamil Nadu, shared that his village was less affected by the 2004 Tsunami compared to nearby villages due to the presence of mangrove forests. This surprised Sarita, Shabnam, and Shijo. They wondered if mangroves were protecting the village. Can you help them understand this?

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✅ Answer:

👉 Yes, mangroves protect coastal areas ✔️

🌿 Role of Mangroves:

• 🌊 Act as natural barriers
• 💨 Reduce speed of strong waves & winds
• 🌱 Roots hold soil → prevent erosion

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📌 Conclusion:

👉 Mangroves protect villages from disasters like tsunamis ✔️

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🟢 4. Look at this food chain:

Grass → Grasshopper → Frog → Snake

If frogs disappear from this ecosystem, what will happen to the population of grasshoppers and snakes? Why?

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✅ Answer:

🦗 Grasshoppers:

👉 Population will increase 📈

❌ No frogs to eat them

🐍 Snakes:

👉 Population will decrease 📉

❌ Lose their food (frogs)

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📌 Conclusion:

👉 Food chain becomes imbalanced (असंतुलित)

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🟢 Question 5 and 6 of Class 8 Science Curiosity Chapter 12

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🟢 5. In a school garden, students noticed fewer butterflies the previous season. What could be the possible reasons? What steps can students take to have more butterflies on campus?

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✅ Answer:

🔍 Possible Reasons:

• 🌸 Fewer flowering plants (less nectar)
• ☠️ Use of pesticides
• 🌦️ Climate or habitat changes

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🌱 Steps to Increase Butterflies:

• 🌺 Grow more flowering plants
• 🚫 Avoid chemical pesticides
• 🌿 Maintain natural habitat

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📌 Conclusion:

👉 Healthy environment = more butterflies 🦋

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🟢 6. Why is it not possible to have an ecosystem with only producers and no consumers or decomposers?

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✅ Answer:

🌱 Producers:

👉 Make food

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❌ Without consumers:

👉 No one will use the food

❌ Without decomposers:

👉 Dead matter will accumulate

👉 Nutrients will not recycle

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📌 Conclusion:

👉 All three are necessary:

• 🌱 Producers
• 🐾 Consumers
• ♻️ Decomposers

👉 For a balanced ecosystem ✔️

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🟢 Class 8 Science Curiosity Chapter 12 Question 7 and 8

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🟢 7. Observe two different places near your home or school (e.g., a park and a roadside). List the living and non-living components you see. How are the two ecosystems different?

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✅ Answer:

🌳 Park Ecosystem:

Living:

• 🌳 Trees, grass
• 🐦 Birds, insects
• 🐿️ Squirrels

Non-living:

• 🌱 Soil, water
• ☀️ Sunlight
• 🌬️ Air

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🛣️ Roadside Ecosystem:

Living:

• 🌿 Few plants
• 🐕 Stray dogs
• 🐦 Crows, ants

Non-living:

• 🧱 Concrete
• 🌫️ Dust
• 🚗 Vehicles, heat

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📊 Difference:

• Park → 🌿 High biodiversity & balance
• Roadside → ⚠️ Less greenery, more pollution

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🟢 8. ‘Human-made ecosystems like agricultural fields are necessary, but they must be made sustainable.’ Comment on the statement.

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✅ Answer:

🌾 Importance:

👉 Provide food & resources

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⚠️ Problems (Unsustainable practices):

• ☠️ Excess pesticides
• 🌾 Monoculture
• 💧 Overuse of water

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🌱 Sustainable Solutions:

• 🌿 Organic farming
• 🔄 Crop rotation
• 💧 Water conservation

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📌 Conclusion:

👉 Sustainable farming is necessary for future survival ✔️

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🟢 Class 8 Science Curiosity Chapter 12 Question 9

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🟢 9. If the Indian hare population (Fig. 12.20) drops because of a disease, how would it affect the number of other organisms?

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✅ Answer:

🌿 Plants:

👉 Increase 📈 (less eaten by hares)

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🦊 Predators (fox, eagle):

👉 Decrease 📉 (less food)

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🐭 Other prey animals:

👉 May decrease ⚠️ (predators shift to them)

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📌 Conclusion:

👉 One change affects the entire food web (जाल)

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