Chapter 13 — Biodiversity and Conservation
Key Concepts Quick Recap
| Term | Definition |
|---|
| Biodiversity | Variety of life on Earth — genetic, species, ecosystem levels |
| Species diversity | Number of species (species richness) and their relative abundance |
| Genetic diversity | Variation in genes within a species |
| Ecosystem diversity | Variety of habitats, communities, and ecological processes |
| Endemic species | Species found exclusively in one geographic area |
| Keystone species | Species whose removal causes disproportionately large effect on ecosystem |
| Biodiversity hotspot | Region with exceptional endemism and severe habitat loss |
| In situ conservation | Conservation in natural habitat (national parks, sanctuaries, biosphere reserves) |
| Ex situ conservation | Conservation outside natural habitat (zoos, botanical gardens, seed banks) |
I. Choose the Best Answer (MCQs)
1. Which of the following is an example of in situ conservation? (a) Botanical garden (b) Zoological park (c) Biosphere reserve (d) Seed bank
Answer(c) Biosphere reserve In situ conservation protects species in their natural habitat: National parks, Wildlife sanctuaries, Biosphere reserves, Sacred groves. Ex situ conservation is away from natural habitat: Zoos, botanical gardens, seed banks, tissue culture collections.
2. India is one of the mega-diversity countries because it has: (a) High population (b) Large area (c) High species richness and endemism (d) Many rivers
Answer(c) High species richness and endemism India is one of 17 mega-diverse countries — it contains approximately 8% of the world's species in only 2.4% of the Earth's land area. India has ~45,000 plant species and ~90,000 animal species, with high endemism especially in the Western Ghats and Himalayas.
3. The number of biodiversity hotspots in India is: (a) 2 (b) 3 (c) 4 (d) 6
Answer(c) 4 India's four biodiversity hotspots: 1. Western Ghats + Sri Lanka 2. Himalayas (Eastern Himalayas) 3. Indo-Burma (NE India + Myanmar + parts of SE Asia) 4. Sundaland (partly NE India + Andaman & Nicobar Islands)
4. IUCN stands for: (a) International Union for Conservation of Nature (b) Indian Union for Conservation of Nature (c) International Union for Conservation of Natural Resources (d) International Union for Conservation of Nations
Answer(a) International Union for Conservation of Nature IUCN (founded 1948) maintains the Red List — the world's most comprehensive inventory of the threatened status of species. Categories: Extinct (EX), Extinct in Wild (EW), Critically Endangered (CR), Endangered (EN), Vulnerable (VU), Near Threatened (NT), Least Concern (LC).
5. Which of the following is a direct cause of biodiversity loss? (a) Ozone depletion (b) Habitat destruction (c) Global warming (d) Acid rain
Answer(b) Habitat destruction The most significant direct cause of biodiversity loss worldwide. Deforestation, agricultural expansion, urbanisation, and wetland drainage destroy natural habitats. The "evil quartet" (Jared Diamond's term): Habitat loss/fragmentation, Over-exploitation, Alien species invasion, Co-extinctions.
6. Sacred groves are an example of: (a) Ex situ conservation (b) In situ conservation (c) Biosphere reserve (d) Wildlife sanctuary
Answer(b) In situ conservation Sacred groves are patches of forest protected by local communities for religious/cultural reasons. They represent traditional in situ conservation and often harbour rare and endemic species. Examples: Khasi sacred groves (Meghalaya), Dev-vans (Rajasthan), Orans.
7. Gene bank is used for: (a) Storing genetic material of plants (b) Banking money from biodiversity (c) Protecting wildlife (d) Studying animal behavior
Answer(a) Storing genetic material of plants Gene banks (seed banks) store seeds of crop varieties and wild relatives at low temperature and humidity to preserve genetic diversity. Examples: National Bureau of Plant Genetic Resources (NBPGR) in India; Svalbard Global Seed Vault (Norway) — the "Doomsday Vault."
II. Short Answer Questions
Q1. Define biodiversity. Explain its three levels.
Answer
Biodiversity (biological diversity) is the variety and variability among all living organisms on Earth.
Three levels:
1. Genetic diversity: Variation in genes within a species.
- Same species may have different alleles (polymorphism).
- Example: Different varieties of rice (Oryza sativa) — Basmati, Sona Masuri, etc.
- Importance: Genetic diversity enables adaptation to changing environments; raw material for evolution and plant breeding.
2. Species diversity: Variety of species in a given area.
- Measured by species richness (number of species) and evenness (relative abundance).
- Example: Tropical rainforests have higher species diversity than temperate forests.
- India: ~45,000 plant species; ~91,000 animal species.
3. Ecosystem diversity: Variety of ecosystems or habitats in a region.
- Example: India has deserts, grasslands, wetlands, mangroves, coral reefs, tropical forests, alpine meadows.
- High ecosystem diversity → high species diversity.
Q2. What are biodiversity hotspots? Name India's hotspots.
Answer
A biodiversity hotspot is a region that: 1. Contains ≥1,500 endemic plant species (≥ 0.5% of world total). 2. Has lost ≥ 70% of its original habitat due to human activities.
Concept proposed by: Norman Myers (1988).
Currently, 36 hotspots exist worldwide, covering ~2.5% of Earth's land but containing >60% of world's plant, bird, mammal, reptile, and amphibian species.
India's 4 hotspots: 1. Western Ghats + Sri Lanka: Rich in endemic plants, amphibians, reptiles. 2. Himalayas (Eastern): Rich in alpine flora, orchids, mammals. 3. Indo-Burma: Diverse riverine and forest species. 4. Sundaland: Includes Nicobar Islands; diverse marine and forest species.
Q3. Distinguish between in situ and ex situ conservation.
Answer
| Feature | In Situ Conservation | Ex Situ Conservation |
|---|
| Location | In natural habitat | Outside natural habitat |
| Examples | National parks, wildlife sanctuaries, biosphere reserves, sacred groves | Zoos, botanical gardens, aquaria, seed banks, gene banks, tissue culture |
| Advantage | Species adapt, evolve naturally; ecosystem maintained | Protection from immediate threats; scientific study; breeding programmes |
| Disadvantage | Threats remain (poaching, habitat loss) | May lose wild behaviour; genetic drift; expensive maintenance |
| Best for | Mobile and wide-ranging species | Critically endangered species; crop varieties |
Q4. What are the major threats to biodiversity?
1. Habitat loss and fragmentation:
Answer
- Deforestation, urbanisation, agriculture.
- Largest cause: India lost >40% forest cover since independence.
2. Over-exploitation:
Answer
- Hunting, poaching, over-fishing.
- Example: Tiger, Rhinoceros poached for skin/horn.
3. Invasive alien species:
Answer
- Introduced species out-compete native species.
- Example: Water hyacinth (Eichhornia crassipes) chokes Indian lakes; Lantana camara invades forests.
4. Co-extinctions:
Answer
- When one species goes extinct, dependent species also die.
- Example: if a plant goes extinct, its specific pollinator may also go extinct.
5. Pollution:
Answer
- Air, water, soil pollution degrades habitats.
- Pesticides, heavy metals accumulate in food chains (biomagnification).
6. Climate change:
Answer
- Shifting ranges, altered phenology, coral bleaching.
Common Mistakes
- Confusing in situ (natural habitat) and ex situ (outside habitat).
- Saying India has 2 hotspots — it has 4.
- Confusing IUCN categories: CR (Critically Endangered) is more serious than EN (Endangered).
- Saying sacred groves are ex situ — they are in situ (protected patches of natural habitat).
Exam Checklist
- Three levels of biodiversity: genetic, species, ecosystem.
- Hotspot criteria: ≥1500 endemic plants + ≥70% habitat lost.
- India's 4 hotspots: Western Ghats, Himalayas, Indo-Burma, Sundaland.
- In situ: national parks, sanctuaries, biosphere reserves, sacred groves.
- Ex situ: zoos, botanical gardens, seed banks, gene banks.
- Threats: habitat loss, over-exploitation, alien species, co-extinctions (Evil Quartet — Jared Diamond).
- IUCN Red List categories: EX, EW, CR, EN, VU, NT, LC.
