Chapter 21 — Biodiversity and Conservation Exercise Solutions
Conservation is a high-scoring topic. Know the difference between in situ and ex situ with specific Indian examples.
How to Use This Page
1. Start with the Key Concepts table — quickly revise definitions before attempting questions. 2. Attempt MCQs and Fill in the Blanks first — they test recall and are quick marks. 3. Use True or False to catch misconceptions — pay attention to corrections on false statements. 4. Practice Match the Following — it reinforces associations between terms and examples. 5. Write short answers in your own words — the 2-mark answers here are model answers; do not copy verbatim. 6. Study the detail answers for structure — notice the sub-headings and bullet format examiners look for. 7. Review Common Mistakes before every exam — these are the most frequently lost marks.
Key Concepts (Quick Recap)
| Term | Definition |
|---|---|
| Biodiversity | The variety of life forms at all levels — genetic, species, and ecosystem |
| Genetic diversity | Variation in genes within a single species (e.g. different rice cultivars) |
| Species diversity | Number of species and their relative abundance in a given area |
| Ecosystem diversity | Range of different habitats, biotic communities, and ecological processes |
| Latitudinal gradient | Pattern where species richness increases from poles towards the equator |
| Species-area relationship | S = C*A^z — on a log-log plot, species richness is linearly related to area |
| Biodiversity hotspot | A region with ≥1500 endemic vascular plant species and ≥70% habitat loss |
| In situ conservation | Protecting species within their natural habitats (national parks, biosphere reserves) |
| Ex situ conservation | Protecting species outside natural habitats (zoos, seed banks, cryopreservation) |
| IUCN Red List | A global inventory of species' conservation status (EX, EW, CR, EN, VU, NT, LC) |
| Sacred grove | A forest patch protected by local communities for religious or cultural reasons |
| Endemism | Presence of a species restricted to a particular geographic region |
| Cryopreservation | Storing biological material at ultra-low temperatures (often in liquid nitrogen) |
| Biosphere reserve | A protected area that conserves ecosystems while allowing sustainable human use |
| Afforestation | Planting trees in a barren area to restore or create forest cover |
Levels of Biodiversity
| Level | Definition | Example |
|---|---|---|
| Genetic | Variation within species | Different wheat varieties, human blood groups |
| Species | Variety of species in an area | Number of bird species in a forest |
| Ecosystem | Variety of ecosystems/habitats | Forests, grasslands, wetlands in a region |
Global Biodiversity Patterns
- Species richness increases from poles to equator (latitudinal gradient).
- Tropics have greatest biodiversity — stable climate, more solar energy, complex habitats.
- Species-area relationship: S = CA^z (log S vs log A is linear). Larger area = more species.
- India: ~8% of global biodiversity; 2.4% of world's land area.
Threats to Biodiversity — HIPPO
| Letter | Threat | Example |
|---|---|---|
| H | Habitat loss | Deforestation, agriculture expansion |
| I | Invasive species | Lantana in forests, water hyacinth in lakes |
| P | Pollution | Chemical pollutants, plastic |
| P | Population growth | Resource overuse |
| O | Overexploitation | Overhunting, overfishing |
Most important threat: Habitat destruction (especially deforestation).
Conservation Categories (IUCN Red List)
- Extinct (EX): No known individuals surviving.
- Extinct in Wild (EW): Survives only in captivity.
- Critically Endangered (CR): Extremely high risk.
- Endangered (EN): Very high risk.
- Vulnerable (VU): High risk.
- Least Concern (LC): Not threatened.
Protected Areas in India
| Category | Number (approx) | Example |
|---|---|---|
| National Parks | 106 | Kanha, Corbett, Sundarbans |
| Wildlife Sanctuaries | 565 | Vedanthangal, Mudumalai |
| Biosphere Reserves | 18 | Nilgiri, Gulf of Mannar, Sundarbans |
Sacred Groves
- Patches of forest protected by local communities due to religious or cultural beliefs.
- Rich in biodiversity; no cutting or hunting allowed.
- Examples: Devarakadus (Karnataka), Kovils' sacred trees (Tamil Nadu).
Worked Examples
Example 1 — Levels of biodiversity (model answer)
Example 2 — In-situ vs ex-situ conservation
Example 3 — Conservation areas (model answer)
A National Park gives the highest protection — no human activity (grazing, forestry) is allowed. A Wildlife Sanctuary protects animals but permits some regulated human activity. A Biosphere Reserve conserves whole ecosystems along with traditional human life.
Common Mistakes
- Listing only animals when asked about biodiversity — it includes all living organisms (plants, fungi, microbes).
- Confusing National Park (highest protection, no human activity) with Wildlife Sanctuary (limited human activities allowed).
- Stating Western Ghats alone as a hotspot — it is "Western Ghats + Sri Lanka" as one hotspot.
- Forgetting that seed banks and gene banks are ex situ conservation, not in situ.
I. Choose the Best Answer (MCQs)
1. Which level of biodiversity refers to the variety of genes within a single species?
- (a) Species diversity
- (b) Genetic diversity
- (c) Ecological diversity
- (d) Community diversity
2. The latitudinal gradient in biodiversity indicates that:
- (a) Species richness is highest at the poles
- (b) Species richness increases from poles to the equator
- (c) Biodiversity is uniform across all latitudes
- (d) Tropical regions have fewer species than temperate regions
3. In the species-area relationship S = CA^z, the value of z for a species-rich region typically falls around:
- (a) 0.1
- (b) 0.2
- (c) 0.6
- (d) 1.0
4. Which of the following is an example of in situ conservation?
- (a) Seed bank
- (b) Biosphere reserve
- (c) Botanical garden
- (d) Cryopreservation
5. The acronym HIPPO stands for:
- (a) Habitat, Industry, Predation, Population, Overfishing
- (b) Habitat loss, Invasive species, Pollution, Population growth, Overexploitation
- (c) Hunting, Insects, Pollution, Pests, Overgrazing
- (d) Habitat, Infection, Parasitism, Population, Overuse
6. Which of the following IUCN categories indicates a species that survives only in captivity?
- (a) Extinct
- (b) Extinct in the Wild
- (c) Critically Endangered
- (d) Vulnerable
7. How many biodiversity hotspots does India have?
- (a) 2
- (b) 3
- (c) 4
- (d) 5
8. Sacred groves are examples of:
- (a) Ex situ conservation
- (b) In situ conservation
- (c) Captive breeding
- (d) Gene banking
9. Which invasive plant is a major threat to Indian wetlands?
- (a) Lantana camara
- (b) Eichhornia crassipes (water hyacinth)
- (c) Parthenium hysterophorus
- (d) Prosopis juliflora
10. The National Bureau of Plant Genetic Resources (NBPGR) is primarily involved in:
- (a) In situ conservation
- (b) Ex situ conservation through seed banks
- (c) Creating national parks
- (d) Managing biosphere reserves
11. Which of the following is NOT a biodiversity hotspot in India?
- (a) Western Ghats
- (b) Himalaya
- (c) Indo-Burma
- (d) Deccan Plateau
12. According to the IUCN Red List, a species classified as "Vulnerable" faces:
- (a) Extremely high risk of extinction in the wild
- (b) Very high risk of extinction in the wild
- (c) High risk of extinction in the wild
- (d) Low risk of extinction
II. Fill in the Blanks
1. The three levels of biodiversity are genetic, species, and ecosystem diversity.
2. The species-area relationship is expressed as S = CA^z, where S is species richness and A is area.
3. The greatest threat to biodiversity is habitat loss / habitat destruction.
4. A biodiversity hotspot must have at least 1500 endemic vascular plant species.
5. The Nilgiri Biosphere Reserve is located in the Western Ghats biodiversity hotspot.
6. Cryopreservation involves storing biological material at very low temperatures, typically in liquid nitrogen at –196°C.
7. India has 4 biodiversity hotspots.
8. The IUCN Red List category for a species that no longer exists in the wild but survives in captivity is Extinct in the Wild (EW).
9. Sacred groves in Karnataka are locally called Devarakadus.
10. In the HIPPO acronym, the two P's stand for Pollution and Population growth.
III. True or False (with corrections)
1. True or False: Species diversity is the only level of biodiversity that matters for conservation.
- False. All three levels — genetic, species, and ecosystem diversity — are important. Genetic diversity provides resilience; ecosystem diversity provides habitat variety.
2. True or False: The tropics have higher biodiversity than temperate regions.
- True. The latitudinal gradient shows species richness increases from poles to equator due to stable climate, more solar energy, and longer evolutionary time in tropics.
3. True or False: A national park allows regulated grazing and forestry activities.
- False. A national park provides the highest protection — no human activity such as grazing, forestry, or cultivation is allowed. Regulated activities are permitted in wildlife sanctuaries, not national parks.
4. True or False: Seed banks are a form of in situ conservation.
- False. Seed banks are an ex situ conservation method because they store seeds outside the natural habitat. In situ conservation protects species in their natural environment.
5. True or False: The Western Ghats is a biodiversity hotspot on its own.
- False. The hotspot is "Western Ghats and Sri Lanka" — it is treated as a single biogeographic unit under the hotspot criteria.
6. True or False: The value of z in the species-area relationship is always 0.1.
- False. The value of z ranges from 0.1 to 0.3 for smaller areas and is approximately 0.6 for species-rich continental areas. It is not constant.
7. True or False: Extinct in the Wild (EW) means the species has completely disappeared from the earth.
- False. Extinct in the Wild means the species survives only in captivity or cultivated populations. Complete disappearance from everywhere is classified as Extinct (EX).
8. True or False: Sacred groves are a community-based in situ conservation strategy.
- True. Sacred groves are forest patches protected by local communities for religious or cultural reasons, making them an effective form of in situ conservation.
IV. Match the Following
| Column A | Column B |
|---|---|
| 1. Genetic diversity | (d) Variation in alleles within a species |
| 2. Species-area relationship | (g) S = CA^z |
| 3. Lantana camara | (e) Invasive species in Indian forests |
| 4. Critically Endangered | (a) Extremely high risk of extinction in the wild |
| 5. National Park | (c) No human activity permitted |
| 6. Seed bank | (h) Ex situ conservation |
| 7. Western Ghats | (b) Biodiversity hotspot with high endemism |
| 8. Sacred grove | (f) Community-protected forest patch |
Key: 1–d, 2–g, 3–e, 4–a, 5–c, 6–h, 7–b, 8–f
V. Answer Briefly (2-mark)
1. What is the latitudinal gradient in biodiversity? Biodiversity increases from the poles towards the equator. Tropical regions (near the equator) have far more species than temperate or polar regions. This pattern is called the latitudinal gradient. For example, Colombia has roughly 1,400 bird species while the Arctic has very few. The reasons include a more stable tropical climate, greater solar energy input, and longer periods without glaciation allowing more evolutionary time.
2. Distinguish between endangered and vulnerable species. An endangered species (EN) faces a very high risk of extinction in the wild in the near future. A vulnerable species (VU) faces a high risk of extinction but the risk is less immediate than for endangered species. For example, the Bengal tiger is endangered, while the Indian rhinoceros was previously vulnerable but has recovered in some areas. Both categories are part of the IUCN Red List and require conservation attention.
3. Why are the tropics richer in biodiversity than temperate regions? Tropical regions receive more solar energy, supporting greater primary productivity. The climate is relatively stable without freezing winters, allowing species to survive year-round. Tropics have had a longer evolutionary time without major glaciation events, giving species more time to diversify. The complex habitat structure (canopy layers in rainforests) also provides more ecological niches for species to occupy.
4. Name two invasive species in India and explain their impact. Lantana camara — a shrub that invades forest understories, displacing native grasses and shrubs, reducing food availability for herbivores. Eichhornia crassipes (water hyacinth) — clogs lakes and rivers, blocking sunlight and oxygen, leading to fish kills and reduced water quality. Both invasive species outcompete native species and alter ecosystem functioning, contributing to biodiversity loss.
5. What are sacred groves? Give two examples. Sacred groves are patches of forest that local communities protect for religious or cultural reasons. Hunting, tree felling, and grazing are traditionally prohibited in these areas, preserving biodiversity. In Karnataka they are called Devarakadus, and in Tamil Nadu they are associated with temple forests (Kovil Kaadugal). These groves often serve as the last refuge for rare and endemic species.
6. Write the species-area relationship equation and explain each term. The species-area relationship is given by S = CA^z, where: S = species richness (number of species), C = a constant that depends on the taxonomic group and region, A = area of the region, and z = the slope of the line on a log-log plot (typically 0.1–0.3 for islands, ~0.6 for continents). On a logarithmic scale, the relationship becomes log S = log C + z log A, producing a straight line.
VI. Answer in Detail (5-mark)
Common Mistakes to Avoid
- ❌ Writing "Western Ghats" alone as a hotspot → ✅ Always write "Western Ghats and Sri Lanka" — they form a single hotspot.
- ❌ Saying seed banks are in situ conservation → ✅ Seed banks, gene banks, and cryopreservation are ex situ — species are stored outside their natural habitat.
- ❌ Confusing National Park and Wildlife Sanctuary → ✅ National Parks have the strictest protection with no human activity; Sanctuaries allow limited regulated activities.
- ❌ Thinking biodiversity refers only to animals → ✅ Biodiversity includes all living organisms — plants, animals, fungi, bacteria, and protists.
- ❌ Writing "z is always 0.1" for the species-area relationship → ✅ z varies: 0.1–0.3 for islands/small areas, ~0.6 for large continental areas.
- ❌ Listing only one "P" in HIPPO → ✅ HIPPO has two P's: Pollution and Population growth — both must be mentioned.
- ❌ Confusing Extinct (EX) with Extinct in the Wild (EW) → ✅ EX means no individuals survive anywhere; EW means the species survives only in captivity or cultivation.
- ❌ Omitting the 70% habitat loss criterion for hotspots → ✅ A hotspot must have both ≥1500 endemic plant species AND ≥70% habitat loss — both criteria are essential.
Exam Checklist
- [ ] Can you define and give examples for all three levels of biodiversity (genetic, species, ecosystem)?
- [ ] Can you explain the latitudinal gradient and why tropics are more biodiverse?
- [ ] Can you write the species-area relationship equation (S = CA^z) and explain each term?
- [ ] Can you list all five components of HIPPO with Indian examples?
- [ ] Can you distinguish between in situ and ex situ conservation with at least three examples each?
- [ ] Can you name India's four biodiversity hotspots and describe at least one key feature of each?
- [ ] Can you list and define the IUCN Red List categories in order (EX → LC)?
- [ ] Can you differentiate National Parks, Wildlife Sanctuaries, and Biosphere Reserves?
- [ ] Can you explain what sacred groves are and name two regional examples?
- [ ] Do you know the two criteria for identifying a biodiversity hotspot (≥1500 endemic species, ≥70% habitat loss)?
- [ ] Can you name at least two invasive species in India and explain their impact?
- [ ] Can you explain the significance of the species-area relationship for predicting extinction from habitat loss?