🌸Chapter 13
Biodiversity and Conservation
(Biology Notes)
1. Introduction to Biodiversity
Definition:
- Biodiversity refers to the variety and
variability of living organisms from all sources, including
terrestrial, marine, and other aquatic ecosystems.
- It includes diversity within
species, between species, and of ecosystems.
- E.O. Wilson (1988): Biodiversity is “the totality
of genes, species, and ecosystems of a region.”
Significance:
- Ensures ecosystem stability.
- Provides resources for food,
medicine, industry, and agriculture.
- Maintains ecological balance.
NCERT Keyword: Variety of life, gene pool, ecosystem.
2. Levels of Biodiversity
A. Genetic Diversity
- Definition: Variation in genes within a
species.
- Importance:
- Provides raw material for
evolution.
- Helps in adaptation to
environmental changes.
- Example: Different varieties of rice,
wheat, and cattle breeds.
B. Species Diversity
- Definition: Variety of species in a
region.
- Components:
- Species richness: Number of species.
- Species evenness: Relative abundance of
species.
- Example: Forests of Western Ghats, Sundarbans
mangroves.
C. Ecosystem Diversity
- Definition: Variety of ecosystems in a
region.
- Example: Forests, grasslands, deserts,
wetlands, coral reefs.
NCERT Keyword: Genes, species richness, ecosystem types.
3. Measurement of Biodiversity
A. Species Richness
- Total number of species in a
given area.
B. Simpson’s Index of Diversity
- Measures species diversity
taking into account species richness and evenness.
D=1−∑ni(ni−1)N(N−1)D = 1 - \frac{\sum n_i(n_i -
1)}{N(N-1)}D=1−N(N−1)∑ni(ni−1)
Where:
- nin_ini = number of
individuals of species iii
- NNN = total number of
individuals of all species
Interpretation: Higher DDD indicates higher diversity.
NCERT Keyword: Species richness, Simpson’s index.
4. Biodiversity at Global, National,
and Local Levels
|
Level |
Example |
|
Global |
Amazon rainforest, Great Barrier Reef |
|
National |
Western Ghats, Himalayas |
|
Local |
Village pond, home garden |
Biodiversity Hotspots (Global Criteria):
- Rich in species, endemic
species ≥ 1500, threatened species.
- India Hotspots (4 of 36
global):
1.
Himalaya
2.
Indo-Burma
3.
Sundalands
(Nicobar)
4.
Indo-Malayan
region
NCERT Keyword: Endemic species, hotspots.
5. Importance of Biodiversity
A. Ecological Importance
- Maintains food chains &
nutrient cycles.
- Supports ecosystem services
like pollination, decomposition, climate regulation.
B. Economic Importance
- Provides resources:
- Food: Crops, fruits, livestock
- Medicine: Taxol (yew tree), Artemisinin
(malaria)
- Industries: Timber, paper, rubber
C. Social & Cultural Importance
- Spiritual and religious values
(Sacred groves in India).
- Ecotourism and recreation.
D. Scientific Importance
- Research, bioprospecting, and
genetic engineering.
NCERT Keyword: Ecosystem services, medicinal plants, genetic resources.
6. Threats to Biodiversity
A. Habitat Loss
- Urbanization, deforestation,
mining, agriculture.
- Example: Wetlands converted to
farmland.
B. Overexploitation
- Hunting, fishing, logging
beyond sustainable limits.
C. Invasive Species
- Non-native species disturb
ecosystems.
- Example: Lantana in India, Water hyacinth.
D. Pollution
- Air, water, soil pollution
adversely affects species.
E. Climate Change
- Global warming, sea-level rise,
and altered rainfall patterns threaten biodiversity.
NCERT Keyword: Anthropogenic activities, invasive species, global warming.
7. Conservation of Biodiversity
A. In-Situ Conservation (On-site)
- Protecting species in their
natural habitat.
- Methods & Examples:
- National Parks: Jim Corbett, Kaziranga
- Wildlife Sanctuaries: Bharatpur, Periyar
- Biosphere Reserves: Nilgiri, Sunderbans
- Sacred Groves: Protects endemic species
Diagram Idea: Map showing National Parks & Biosphere Reserves in
India.
B. Ex-Situ Conservation (Off-site)
- Protecting species outside
their natural habitat.
- Methods & Examples:
- Botanical Gardens: Lalbagh (Bangalore)
- Zoos & Wildlife Parks: Delhi Zoo
- Seed Banks: Svalbard Global Seed Vault,
NBPGR (India)
- Tissue Culture: For rare medicinal plants
NCERT Keyword: In-situ, ex-situ, wildlife sanctuaries, biosphere reserves.
8. Endangered and Threatened Species
in India
Red Data Book (IUCN): Lists critically endangered, endangered, and vulnerable
species.
- Examples:
- Tiger – Panthera tigris
- One-horned Rhinoceros – Rhinoceros unicornis
- Asiatic Lion – Panthera leo persica
NCERT Keyword: Critically endangered, IUCN Red List.
9. Biodiversity Conservation
Programs in India
- Wildlife Protection Act, 1972 – Protect species &
habitats.
- Forest Conservation Act, 1980 – Regulate deforestation.
- Project Tiger (1973) – Tiger conservation.
- Project Elephant (1992) – Elephant conservation.
- Biosphere Reserve Program – UNESCO-supported
eco-protection.
NCERT Keyword: Project Tiger, Project Elephant, Wildlife Act.
10. Role of Community in
Biodiversity Conservation
- Involvement of local
communities in managing forests, wetlands, and sacred groves.
- Promotion of sustainable
agriculture and eco-tourism.
NCERT Keyword: Community-based conservation, sustainable use.
11. Summary Table
|
Aspect |
Key Points |
|
Biodiversity |
Variety of life at genetic, species, ecosystem levels |
|
Importance |
Ecological, economic, social, scientific |
|
Threats |
Habitat loss, overexploitation, invasive species,
pollution, climate change |
|
Conservation |
In-situ (parks, sanctuaries), Ex-situ (zoos, seed banks) |
|
India Focus |
Hotspots: Himalaya, Indo-Burma, Sundalands; Projects: Tiger,
Elephant |
12. Diagrams for Revision
1.
Levels
of Biodiversity
(Genetic → Species → Ecosystem)
2.
In-situ
& Ex-situ Conservation
(Parks, Zoos, Botanical Gardens, Seed Banks)
3.
Biodiversity
Hotspots in India
(Map)
13. Important Definitions &
NCERT Keywords
- Biodiversity: Variety of life forms.
- Endemic species: Species restricted to a
region.
- Genetic Diversity: Variation of genes in species.
- Species Diversity: Variety of species in a
habitat.
- Ecosystem Diversity: Variety of ecosystems.
- Hotspot: Region with rich, endemic
biodiversity.
- In-situ Conservation: Protecting species in natural
habitat.
- Ex-situ Conservation: Protecting species outside
natural habitat.
✅ Exam Tips:
- For Board exams:
Remember definitions, examples of conservation projects, and diagrams.
- For NEET: Focus on
biodiversity indices, species types, endemic species, threats, and
conservation strategies.
- Always link concepts with
examples from India.
