class 11 notes

Class 11 Geography Notes Chapter 16 (Biodiversity and conservation) – Fundamental of Physical Geography Book

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Fundamental of Physical Geography
Detailed Notes with MCQs of Chapter 16: Biodiversity and Conservation from your 'Fundamentals of Physical Geography' textbook. This is a crucial chapter, not just for understanding our planet, but also frequently tested in various government examinations. Pay close attention to the key terms and concepts.

Chapter 16: Biodiversity and Conservation - Detailed Notes

1. What is Biodiversity?

  • Definition: Biodiversity, or Biological Diversity, refers to the variety and variability of life forms on Earth. It encompasses all the different plants, animals, micro-organisms, the genes they contain, and the ecosystems they form.
  • Origin: The term was popularized by sociobiologist Edward Wilson.
  • Levels of Biodiversity: It exists at three hierarchical levels:
    • Genetic Diversity: Variation in genes within a single species. This allows species to adapt to environmental changes. Example: Different varieties of rice or mangoes; variations within human populations. High genetic diversity is essential for a species' long-term survival.
    • Species Diversity: Variety of different species (species richness) present in a specific area and their relative abundance (species evenness). Example: A tropical rainforest has higher species diversity than a temperate grassland.
    • Ecosystem/Ecological Diversity: Variety of habitats, biotic communities, and ecological processes within a specific geographic area. It refers to the diversity of ecosystems like deserts, rainforests, mangroves, coral reefs, wetlands, estuaries, and alpine meadows.

2. Importance of Biodiversity

Biodiversity provides numerous benefits essential for human survival and well-being:

  • Ecological Role:
    • Ecosystem Stability: Diverse ecosystems are generally more stable and resilient to disturbances.
    • Nutrient Cycling: Microorganisms and plants play vital roles in cycles like carbon, nitrogen, and water.
    • Pollination & Seed Dispersal: Insects, birds, and bats are crucial pollinators; animals help disperse seeds.
    • Climate Regulation: Forests influence rainfall patterns and absorb carbon dioxide.
    • Waste Decomposition: Microbes break down organic waste.
    • Pest and Disease Control: Natural predators keep pest populations in check.
    • Soil Formation & Protection: Vegetation prevents soil erosion.
  • Economic Role:
    • Food: Provides crops, livestock, forestry, and fish.
    • Medicines: Many drugs are derived from plants and microorganisms (e.g., Quinine from Cinchona tree, Penicillin from fungus). Traditional medicine systems heavily rely on biodiversity.
    • Fibre, Fuelwood, Timber: Provides essential resources for clothing, shelter, and energy.
    • Industrial Products: Source of tannins, lubricants, dyes, resins, perfumes, etc.
    • Tourism & Recreation: Ecotourism generates significant revenue based on rich biodiversity (e.g., wildlife safaris).
  • Scientific Role:
    • Understanding life processes and evolution.
    • Source of genetic resources for crop improvement and biotechnology.
    • Ecological research depends on studying interactions within diverse ecosystems.
  • Ethical and Social Role:
    • Every species has an intrinsic right to exist, regardless of its direct use to humans.
    • Aesthetic value – provides beauty and inspiration.
    • Cultural value – many plants and animals are part of cultural and religious beliefs.

3. Loss of Biodiversity

  • The world is facing an accelerated rate of species extinction, largely due to human activities. This is often referred to as the "Sixth Extinction".
  • Major Causes (The 'Evil Quartet'):
    • Habitat Loss and Fragmentation: This is the primary driver. Destruction of natural habitats (forests, wetlands, grasslands) for agriculture, urbanization, mining, and infrastructure development. Fragmentation breaks large habitats into smaller, isolated patches, reducing resources and genetic exchange.
    • Over-exploitation: Harvesting resources (hunting, fishing, logging) at unsustainable rates. Examples: Overfishing leading to depletion of fish stocks; hunting leading to extinction (e.g., Steller's sea cow, passenger pigeon).
    • Alien Species Invasions: Introduction of non-native species (intentionally or accidentally) that outcompete native species for resources, prey upon them, or introduce diseases. Examples: Nile Perch in Lake Victoria causing extinction of cichlid fish; Water Hyacinth choking water bodies in India; Lantana camara.
    • Co-extinctions: When a species becomes extinct, plant and animal species associated with it in an obligatory way also become extinct. Example: Extinction of a host fish leads to the extinction of its unique parasites.
  • Other Factors: Pollution (pesticides, industrial effluents), Climate Change (altering habitats and species' ranges).

4. Biodiversity Hotspots

  • Concept: Areas characterized by very high levels of species richness and high degree of endemism (species confined to that region and not found anywhere else).
  • Criteria (defined by Norman Myers/Conservation International):
    1. Must have at least 1,500 vascular plants as endemics (>0.5% of the world's total).
    2. Must have lost at least 70% of its original habitat (high degree of threat).
  • Purpose: These hotspots represent areas where conservation efforts can be maximized to protect a large number of unique species facing imminent extinction. Globally, 36 hotspots have been identified.
  • Hotspots in India: India has four designated biodiversity hotspots:
    1. Himalaya: Includes the entire Indian Himalayan region.
    2. Indo-Burma: Covers northeastern India (excluding Assam and Andaman Islands), Myanmar, Thailand, Vietnam, Laos, Cambodia, and southern China.
    3. Western Ghats and Sri Lanka: Includes the entire Western Ghats region and Sri Lanka.
    4. Sundaland: Includes the Nicobar Islands (part of the Indonesian archipelago region).

5. Conservation of Biodiversity

  • Why Conserve?
    • Narrowly Utilitarian: Direct economic benefits (food, fuel, medicine, industrial products).
    • Broadly Utilitarian: Ecosystem services (pollination, climate regulation, oxygen production).
    • Ethical: Intrinsic value of all species; moral duty to protect life forms.
  • How to Conserve? Methods:
    • In-situ Conservation (On-site): Protecting species in their natural habitats. This is generally considered the best strategy.
      • National Parks: Areas strictly reserved for wildlife & biodiversity protection; activities like forestry, grazing, cultivation are not permitted. Example: Jim Corbett National Park.
      • Wildlife Sanctuaries: Areas where protection is given mainly to fauna; certain human activities (like timber harvesting, collection of minor forest products, private ownership rights) might be allowed if they don't harm wildlife. Example: Periyar Wildlife Sanctuary.
      • Biosphere Reserves: Large, multi-purpose protected areas promoting conservation along with sustainable use. They have three zones: Core (strict protection), Buffer (research, education, limited human activity), and Transition (sustainable human settlements and activities). Example: Nilgiri Biosphere Reserve.
      • Sacred Groves/Lakes: Tracts of forest or water bodies protected by local communities based on religious beliefs. Found in many parts of India (e.g., Khasi & Jaintia Hills, Aravalli Hills).
    • Ex-situ Conservation (Off-site): Protecting threatened species outside their natural habitats. Used when species are critically endangered or their habitats are destroyed.
      • Botanical Gardens: Cultivate rare and threatened plant species.
      • Zoological Parks (Zoos): Maintain threatened animal species, often with captive breeding programs.
      • Seed Banks: Store seeds of different genetic strains of commercially important plants and threatened species at low temperatures.
      • Gene Banks/Cryopreservation: Preserve genetic material (gametes, tissues) of threatened species at very low temperatures (-196°C in liquid nitrogen).
      • Tissue Culture: Propagate rare or endangered plants rapidly.

6. International Efforts & Conventions

  • The Earth Summit (Rio de Janeiro, 1992): Led to the Convention on Biological Diversity (CBD). Its objectives are:
    1. Conservation of biodiversity.
    2. Sustainable use of its components.
    3. Fair and equitable sharing of benefits arising from genetic resources.
  • World Summit on Sustainable Development (Johannesburg, 2002): Reaffirmed commitments to biodiversity conservation.
  • (Note: While CITES, Ramsar Convention etc. are important, the NCERT chapter primarily focuses on the concept and CBD).

Multiple Choice Questions (MCQs)

  1. Which level of biodiversity refers to the variety of genes within a single species?
    (a) Ecosystem Diversity
    (b) Species Diversity
    (c) Genetic Diversity
    (d) Ecological Diversity

  2. The concept of 'Biodiversity Hotspots' was primarily developed to prioritize areas with:
    (a) High population density and low endemism
    (b) High species richness and high degree of threat
    (c) Low species richness and low endemism
    (d) High economic value only

  3. Which of the following is considered the most important cause driving animals and plants to extinction?
    (a) Alien species invasion
    (b) Over-exploitation
    (c) Co-extinctions
    (d) Habitat loss and fragmentation

  4. Which of the following is an example of Ex-situ conservation?
    (a) National Park
    (b) Biosphere Reserve
    (c) Seed Bank
    (d) Sacred Grove

  5. Which of the following is NOT one of the recognized Biodiversity Hotspots in India?
    (a) Western Ghats
    (b) Himalaya
    (c) Eastern Ghats
    (d) Indo-Burma

  6. The 'Evil Quartet' is a term used to describe the major causes of:
    (a) Climate Change
    (b) Biodiversity Loss
    (c) Ozone Depletion
    (d) Soil Erosion

  7. Protecting an endangered species by maintaining it in a Zoological Park is an example of:
    (a) In-situ conservation
    (b) Ex-situ conservation
    (c) Co-extinction prevention
    (d) Ecosystem restoration

  8. Endemic species are those which are:
    (a) Found all over the world
    (b) Critically endangered
    (c) Confined to a particular region and not found elsewhere
    (d) Introduced from other countries

  9. The Convention on Biological Diversity (CBD) was signed during which major international conference?
    (a) Stockholm Conference, 1972
    (b) Earth Summit, Rio de Janeiro, 1992
    (c) World Summit on Sustainable Development, Johannesburg, 2002
    (d) Kyoto Protocol Conference, 1997

  10. Sacred Groves are examples of community-based conservation efforts that fall under:
    (a) Ex-situ conservation
    (b) Genetic engineering
    (c) In-situ conservation
    (d) Alien species control

Answer Key:

  1. (c)
  2. (b)
  3. (d)
  4. (c)
  5. (c)
  6. (b)
  7. (b)
  8. (c)
  9. (b)
  10. (c)

Make sure you revise these notes thoroughly. Understanding the definitions, examples, and differences between concepts like in-situ and ex-situ conservation is key for your exams. Good luck with your preparation!

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