Class 12 Biology – Biodiversity and Conservation Notes

Class 12 Biology – Biodiversity and Conservation Notes

1. Introduction to Biodiversity

  • Biodiversity: Variety of life at genetic, species, and ecosystem levels.
  • Importance:
    • Provides food, medicine, fuel, and raw materials
    • Maintains ecological balance
    • Source of cultural and aesthetic value
  • Levels of Biodiversity:
    1. Genetic diversity – Variation of genes within a species
    2. Species diversity – Number of species in an ecosystem
    3. Ecosystem diversity – Variety of ecosystems in a region

2. Threats to Biodiversity

  • Habitat loss and fragmentation
  • Overexploitation of resources
  • Pollution
  • Climate change
  • Invasive alien species
  • Human activities (deforestation, urbanization)

3. Conservation of Biodiversity

A. In-situ Conservation

  • Conservation within natural habitat
  • Examples:
    • National Parks – Protected areas for wildlife
    • Wildlife Sanctuaries – Protect species and habitats
    • Biosphere Reserves – Core, buffer, and transition zones

B. Ex-situ Conservation

  • Conservation outside natural habitat
  • Examples:
    • Botanical gardens – Protect plant species
    • Seed banks – Store seeds for future use
    • Zoos and aquaria – Protect endangered animals
    • Tissue culture – Grow plants in lab conditions

4. Hotspots of Biodiversity

  • Regions with high species richness and endemism.
  • Criteria: At least 1500 species of vascular plants as endemics & loss of 70% habitat.
  • Example hotspots:
    • Himalaya
    • Indo-Burma
    • Sundalands
    • Western Ghats (India)
    • Indo-Malayan region

5. Endangered and Threatened Species

  • Endangered species – At risk of extinction (e.g., Tiger, Asian Elephant)
  • Vulnerable species – Likely to become endangered (e.g., Snow Leopard)
  • Extinct species – No longer exists (e.g., Dodo)
  • Red Data Book – Published by IUCN listing threatened species

6. Role of Biodiversity in Ecosystem

  • Maintains ecological balance
  • Supports food webs and nutrient cycling
  • Provides genetic resources for agriculture and medicine

Ecology: Biodiversity and Conservation | MCQs

1. Basics of Biodiversity

  1. Biodiversity refers to:
    a) Variety of minerals
    b) Variety of life at genetic, species, and ecosystem levels
    c) Only variety of plants
    d) Only variety of animals
    Answer: b) Variety of life at genetic, species, and ecosystem levels
  2. Genetic diversity is:
    a) Variation of ecosystems
    b) Variation of genes within a species
    c) Number of species in a region
    d) Variety of habitats
    Answer: b) Variation of genes within a species
  3. Species diversity refers to:
    a) Variety of ecosystems
    b) Number of species in an ecosystem
    c) Genetic variations within a species
    d) Only endangered species
    Answer: b) Number of species in an ecosystem
  4. Ecosystem diversity refers to:
    a) Variety of genes in a population
    b) Variety of species in a region
    c) Variety of ecosystems in a region
    d) Only forests
    Answer: c) Variety of ecosystems in a region

2. Threats to Biodiversity

  1. Which of the following is a major threat to biodiversity?
    a) Habitat loss
    b) Overexploitation
    c) Pollution and invasive species
    d) All of the above
    Answer: d) All of the above
  2. Introduction of species from another region that harms native species is called:
    a) Habitat fragmentation
    b) Invasive alien species
    c) Endemism
    d) Ecological succession
    Answer: b) Invasive alien species
  3. Climate change can affect biodiversity by:
    a) Altering habitats
    b) Affecting species distribution
    c) Causing extinction
    d) All of the above
    Answer: d) All of the above

3. Conservation of Biodiversity

  1. In-situ conservation means:
    a) Conservation outside natural habitat
    b) Conservation within natural habitat
    c) Storing seeds in seed banks
    d) Tissue culture
    Answer: b) Conservation within natural habitat
  2. Ex-situ conservation involves:
    a) National parks
    b) Wildlife sanctuaries
    c) Zoos, aquaria, botanical gardens
    d) Biosphere reserves
    Answer: c) Zoos, aquaria, botanical gardens
  3. Biosphere reserves consist of:
    a) Only core zone
    b) Only buffer zone
    c) Core, buffer, and transition zones
    d) Only transition zone
    Answer: c) Core, buffer, and transition zones

4. Biodiversity Hotspots

  1. A biodiversity hotspot is a region with:
    a) Low species richness
    b) High species richness and endemism
    c) No endemic species
    d) Only forests
    Answer: b) High species richness and endemism
  2. Which of the following is a biodiversity hotspot in India?
    a) Western Ghats
    b) Eastern Himalaya
    c) Indo-Burma region
    d) All of the above
    Answer: d) All of the above

5. Endangered and Threatened Species

  1. Species at risk of extinction are called:
    a) Vulnerable species
    b) Endangered species
    c) Extinct species
    d) Common species
    Answer: b) Endangered species
  2. Dodo is an example of:
    a) Endangered species
    b) Vulnerable species
    c) Extinct species
    d) Common species
    Answer: c) Extinct species
  3. Red Data Book is published by:
    a) UNESCO
    b) WHO
    c) IUCN
    d) FAO
    Answer: c) IUCN