Biology · BotanyBOT 14
Biodiversity & Conservation
Hotspots, HIPPO causes, in-situ vs ex-situ conservation, species-area relationship
Concept Core
Essential theory — everything NCERT tests on Biodiversity & Conservation
LEVELS OF BIODIVERSITY
Genetic: variation within species. Species: variety between species (most studied). Ecosystem: variety of habitats.
Latitudinal gradient: species richness increases toward tropics. Reasons: stable climate, more solar energy, faster speciation, longer evolutionary time.
India: 2.4% land → 8.1% global biodiversity.
SPECIES-AREA RELATIONSHIP
Alexander von Humboldt: first documented latitudinal gradient.
log S = log C + Z·log A
Z = 0.1–0.2: small isolated areas. Z = 0.6–1.2: large continents. S = species richness, A = area, C = Y-intercept.
BIODIVERSITY HOTSPOTS
Criteria: >1,500 endemic plant species AND lost >70% original habitat.
34 hotspots worldwide. Cover <2% of Earth but harbour >50% of species.
India's hotspots: (1) Western Ghats+Sri Lanka, (2) Eastern Himalayas, (3) Indo-Burma, (4) Sundaland (partially, Andaman-Nicobar).
CAUSES OF LOSS — HIPPO
Habitat loss & fragmentation (#1 globally — deforestation, urbanisation)
Invasive species (Nile perch → 200 cichlid extinctions, Lake Victoria)
Pollution, Population explosion, Over-exploitation/hunting
CONSERVATION STRATEGIES
In-situ: in natural habitat. National parks, wildlife sanctuaries, biosphere reserves, sacred groves.
Ex-situ: outside natural habitat. Zoos, botanical gardens, gene/seed banks, cryopreservation, tissue culture.
India: 90 national parks, 448 wildlife sanctuaries, 14 biosphere reserves (NCERT numbers).
Fact & Formula Vault
High-yield facts, numbers, and formulas
Key Numbers
~7 million estimated species total
~1.5 million species described
34 hotspots; <2% land = >50% species
India: 2.4% area → 8.1% biodiversity
Species-Area Z Values
Z = 0.1–0.2: small/isolated areas
Z = 0.6–1.2: large continents
log S = log C + Z·log A
Higher Z = steeper area-species slope
India Conservation
90 national parks
448 wildlife sanctuaries
14 biosphere reserves
Sacred groves: community in-situ
Worked Examples
NEET-style questions solved step-by-step
EASYWhich of the following is ex-situ conservation?▾
Which of the following is ex-situ conservation?
Seed bank / zoological park / botanical garden / cryopreservation — all are outside natural habitat. National parks and biosphere reserves are in-situ. Sacred groves = in-situ (community-managed).
MEDIUMFor large continental areas, the Z value in species-area relationship is:▾
For large continental areas, the Z value in species-area relationship is:
0.6–1.2. For small isolated areas (islands), Z = 0.1–0.2. The higher Z means species richness scales more steeply with area on a continental scale.
HARDNile perch introduction caused extinction of ~200 cichlid species in Lake Victoria. This is:▾
Nile perch introduction caused extinction of ~200 cichlid species in Lake Victoria. This is:
Alien/invasive species causing biodiversity loss — the 'I' in HIPPO. Nile perch (predatory) eliminated native cichlids. Classic NEET example.
Mistake DNA
Common NEET traps for this chapter
⚠ Number of India hotspots
NCERT XII Ch.15 lists 3 clear Indian hotspots. Some sources say 4 (including Sundaland partially). Use 3 for NEET unless a specific 4th is mentioned in options.
✓ Fix: Western Ghats+SL, E.Himalayas, Indo-Burma = the core 3
⚠ Botanical garden = in-situ?
Botanical gardens are EX-SITU — plants are grown outside their natural habitat in controlled conditions.
✓ Fix: In-situ = in original habitat. Controlled collection = ex-situ
⚠ Biggest cause of loss
Poaching is NOT the biggest cause. Habitat loss (H in HIPPO) is #1 globally.
✓ Fix: HIPPO: Habitat loss first, invasive species second
Chapter Intelligence
Exam data and last-minute strategy
NEET Frequency
2–3 Q/year. HIPPO causes, in-situ vs ex-situ, Z values (0.1–0.2 vs 0.6–1.2), India hotspots, Nile perch example are the most tested.
High-Yield Numbers
34 hotspots. Z = 0.1–0.2 (small) / 0.6–1.2 (large). <2% land = >50% species (hotspots). India: 90 NPs, 448 sanctuaries.
Strategy
Memorise HIPPO. Make in-situ vs ex-situ two-column table. Know the 3 levels of biodiversity. These cover 95% of questions on this chapter.
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