NCERT Class 9 Social Science Chapter 2 Questions and Answers: Life on Earth
Class 9 Social Science Chapter 2: Life on Earth — Questions & Answers
Welcome students! In this post, you will find simple, student-friendly answers to all the questions in Class 9 Social Science (Part 2) Chapter 2: Life on Earth. These solutions will help you understand key concepts easily and score well in your school exams.
Part A: The Big Questions (In-Chapter Core Concepts)
Q1. How do physiography and climate shape life on Earth?
Answer: Physiography (landforms such as mountains, plains, deserts, and valleys) and climate (temperature and rainfall) directly shape life on Earth:
- Formation of Biomes: Landforms and climate together define large natural regions known as biomes (like tundra, hot deserts, tropical forests, and grasslands).
- Plant and Animal Survival: Climate determines which plant species can grow and what vegetation can thrive.
- Adaptations: Animals and plants develop special physical features to survive local conditions—for example, thick fur on cold-region animals or water-storing tissues in desert cacti.
Q2. How are humans and other life forms interconnected?
Answer: Humans, plants, animals, and microorganisms depend on each other within ecosystems:
- Oxygen and Food: Plants provide oxygen, food, timber, and medicinal resources necessary for human life.
- Ecological Services: Animals help in seed dispersal and pollination, while microorganisms recycle nutrients in the soil.
- Human Influence: Humans shape natural environments through farming, cities, and conservation efforts.
Q3. What is the importance of preserving various life forms, and how can we contribute to their conservation?
Answer: Preserving diverse life forms (biodiversity) is essential because it maintains natural ecological balance, stabilizes the climate, protects genetic resources, and ensures human survival.
How we can contribute:
- Supporting ecotourism and nature-friendly practices.
- Protecting forest cover and avoiding habitat destruction.
- Preventing forest fires through awareness and careful management.
- Protecting local sacred groves and supporting community-led forest management.
Part B: Exercise Questions & Activities (End-of-Chapter Solutions)
Q1. Why does India have diverse biomes? How does the local geography connect to the diversity?
Answer: India features diverse biomes because of its wide variety of landforms, elevations, precipitation levels, and temperature zones:
- Geographical Settings: India ranges from the freezing high-altitude Himalayan mountains to arid salt deserts like the Rann of Kutch, dense tropical rainforests, and coastal mangrove belts.
- Local Geography Connection: Local landforms determine the soil, water availability, and climate of a region, giving rise to unique biodiversity hotspots such as the Himalayas, Western Ghats, and North-East India.
Q2. Make a list of economically valuable native plants in your region and comment on their abundance.
Answer: Economically valuable native plants supply essential raw materials, medicines, and food across different Indian regions:
- Wrightia tinctoria (Aale mara): A forest tree from Karnataka used to make famous Channapatna toys. (Abundance: Moderate in forest zones).
- Bamboo and Timber trees: Harvested in Assam, Tripura, and Keralam for construction and handicrafts. (Abundance: High in tropical and eastern forests).
- Medicinal Herbs (Ashwagandha, Neem, Tulsi): Found in the Himalayan region and Western Ghats, widely used for medicine. (Abundance: Moderate to high in protected hill ecosystems).
- Tendu leaves & Mahua flowers: Collected by forest dwellers in Madhya Pradesh and Chhattisgarh for local livelihoods. (Abundance: Abundant in central Indian deciduous forests).
Q3. Prepare a map of your state or Union Territory showing national parks and sanctuaries.
Answer (Guideline for Students): To complete this activity on your map sheet:
- Outline your State or Union Territory boundary.
- Identify key protected areas in or near your state, such as Namdapha National Park (Arunachal Pradesh), Rann of Kutch Sanctuary (Gujarat), Gahirmatha Beach (Odisha), Gulf of Mannar (Tamil Nadu), or Pachmarhi Biosphere Reserve (Madhya Pradesh).
- Mark these locations using standard map symbols (a green square for National Parks and a circle for Sanctuaries) and label them clearly.
Q4. Study the impact of forest fires on people dependent on forests. Try to include the causes, losses, and preventive measures.
Answer:
- Causes: Extreme dry heat, climate change, accumulation of dry leaves/litter, and human negligence.
- Losses/Impacts: Forest fires destroy timber, wild fruits, honey, and medicinal herbs, cutting off the main income source for tribal communities. Fires also destroy wildlife habitats, pollute air, damage forest soil, and endanger human lives.
- Preventive Measures: Creating firebreaks, controlled clearing of dry biomass, setting up local community watch committees via Gram Sabhas, and utilizing satellite detection systems.
Q5. Why are forests often called the ‘lungs of the Earth’?
Answer: Forests are called the ‘lungs of the Earth’ because:
- They absorb large amounts of carbon dioxide from the air during photosynthesis.
- They release fresh oxygen into the atmosphere, which is vital for the breathing of all living beings.
- They help clean the air, balance global climate systems, and maintain oxygen-carbon dioxide balance on the planet.
Q6. If large forest areas continue to be destroyed, what do you think would be its long-term effect on the global climate?
Answer: If large-scale deforestation continues, it will cause severe global consequences:
- Global Warming: Fewer trees mean less carbon dioxide is absorbed, increasing greenhouse gases in the atmosphere and raising global temperatures.
- Extreme Disasters: It leads to more frequent floods, soil erosion, severe droughts, and landslides in mountain areas.
- Loss of Biodiversity: Habitats will be lost, pushing many unique plant and animal species toward extinction.
- Depletion of Commons: Shared natural resources (ecological commons) like water reservoirs and fertile land will shrink and degrade.
Q7. Discuss some traditional forest conservation methods with your grandparents or an elderly person.
Answer: Traditional conservation methods practiced in India include:
- Sacred Groves (Devrai, Devarakadu, Kavu, Sarna): Small patches of forests protected by local villages for religious and cultural reasons. These areas preserve rare species and natural water sources.
- Community Forest Protection Movements: Movements like the historical Bishnoi Movement in Rajasthan (led by Amrita Devi) and the Chipko Movement in Uttarakhand, where villagers physically protected trees from being cut down.
- Sacred Rituals: Tribal communities (like the Gonds and Bhils) perform rituals to honor forest deities before collecting resources, ensuring they never over-extract from nature.
Q8. How do forest dwellers contribute to the protection and conservation of forests?
Answer: Forest dwellers act as traditional guardians of forests in several ways:
- Self-Governance & Management: Villages like Mendha Lekha in Maharashtra use Gram Sabhas to regulate tree cutting, prevent forest fires, and manage resources sustainably under the Forest Rights Act (FRA).
- Traditional Knowledge: They hold generations of knowledge about medicinal herbs and non-timber forest products (NTFPs), collecting resources without harming nature.
- Protecting Biodiversity: Women and local committees actively protect community forests, manage eco-restoration, and maintain sacred groves.
Q9. What is a forest fire? Prepare a plan for prevention and mitigation of forest fires.
Answer: Definition: A forest fire is an uncontrolled fire in forest vegetation or wildlands caused by dry conditions, heatwaves, climate change, or human error.
Prevention & Mitigation Plan:
- Early Detection: Use satellite monitoring tools (such as the School Bhuvan-NCERT Geoportal) to track fire-prone zones.
- Firebreaks & Litter Management: Clear strips of dry fallen leaves and create natural firebreaks before peak summer months.
- Community Involvement: Train local forest dwellers and eco-guards to report and extinguish small fires early.
- Public Awareness: Educate tourists and visitors to prevent accidental fires from campfire sparks or discarded material.
Quick Summary Table: Key Terms to Remember
| Term | Meaning / Description |
|---|---|
| Biome | Large natural regions of the world with similar climate, plants, and animals (e.g., Tundra, Desert, Rainforest). |
| Biodiversity | The variety of all life forms on Earth, including genetic differences and habitats. |
| Sacred Groves | Community-protected forest patches kept safe due to religious and cultural beliefs (Kavu, Devrai, Sarna). |
| Forest Rights Act (2006) | Act granting traditional forest dwellers rights over forest resources and land. |
| GI Tag | Label identifying products originating from a specific place with unique regional qualities (e.g., Kandhamal Haldi, Channapatna Toys). |
| Ecological Commons | Shared natural resources like forests, rivers, and lakes managed collectively by communities. |