CBSE Class 8 Science Question 23 of 26

Conservation of Plants and Animals — Question 23

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Question 8

Explain how deforestation leads to reduced rainfall.

Answer

Trees and plants help maintain the water cycle on Earth. Their roots absorb water from the Earth. This absorbed water goes back into the atmosphere through transpiration from leaves. When trees are cut down, the significant reduction in transpiration decreases the amount of water vapour released into the atmosphere leading to reduced rainfall. Deforestation also reduces cloud formation that reduces rainfall.

Chapter Overview: Conservation of Plants and Animals

This environmental chapter covers deforestation and its consequences, the importance of biodiversity, types of protected areas (biosphere reserves, national parks, wildlife sanctuaries), and concepts like endemic species, Red Data Book, and migration. Reforestation and paper recycling link conservation to everyday action.

Board Exam Weightage: 5-7 marks | Difficulty: Moderate

Key Formulas & Concepts

ConceptDetails
Biosphere ReserveLarge protected area: conservation + research + development (e.g., Pachmarhi, Sundarbans)
National ParkStrictly protected area: no human activity allowed (e.g., Jim Corbett, Kaziranga)
Wildlife SanctuaryAnimals protected, limited human activity like grazing allowed (e.g., Bharatpur, Periyar)
Red Data BookRecord of endangered species maintained by IUCN

Must-Know Concepts

  • Deforestation leads to soil erosion, desertification, floods, global warming, biodiversity loss
  • India is one of 12 mega-biodiversity countries
  • Endemic species are found only in a specific area; endangered species are at risk of extinction
  • Reforestation = replanting where forest existed; Afforestation = planting where forest never was
  • Siberian crane migrates from Siberia to Bharatpur (India) in winter
  • Recycling 1 tonne of paper saves about 17 trees

Protected Areas Comparison

FeatureBiosphere ReserveNational ParkWildlife Sanctuary
SizeLargestMediumSmallest
PurposeConservation + Research + DevelopmentStrict wildlife protectionAnimal protection in natural habitat
Human ActivityLimited (buffer zone)Not allowedLimited (grazing allowed)
ExamplePachmarhi (MP), NilgiriJim Corbett (UK), Gir (GJ)Bharatpur (RJ), Periyar (KL)

Common Mistakes to Avoid

  • Confusing biosphere reserve, national park, and wildlife sanctuary
  • Mixing up endemic (exclusive to area) and endangered (at risk of extinction)
  • Confusing reforestation (re-planting) and afforestation (new planting)
  • Thinking Red Data Book lists ALL species (only endangered ones)

Scoring Tips

  • Make a comparison table of protected areas with examples for each
  • Use memory aids: Endemic = Exclusive location; Endangered = at risk of Ending
  • Memorise 5 national parks and 5 wildlife sanctuaries with states
  • Practice drawing the cause-consequence chain of deforestation

Frequently Asked Questions

Q: How many marks does this chapter carry in the exam?
A: Approximately 5-7 marks in the annual exam.

Q: What question types are commonly asked?
A: MCQs (1 mark), Very Short Answer (2 marks), Short Answer (3 marks), and Long Answer / Diagram (5 marks).

Q: Is this chapter important for competitive exams?
A: Yes, concepts from this chapter appear in NTSE, Olympiad, and other science competitions.