Pocket Notes — Biodiversity and Conservation
3 levels of biodiversity
- Genetic — variation within a species (e.g. Rauwolfia alkaloid content).
- Species — number of species in a region.
- Ecosystem — variety of ecosystems.
Numbers to memorise
- Described species: ~1.5 million
- Robert May's estimate: ~7 million total
- Insects: 70% of animals
- Animals in total species: ~70%
- Plants (incl. algae, fungi): ~22%
- India = 2.4% of land, ~8% of world's species.
Latitudinal gradient
- Species diversity maximum at equator, decreases toward poles.
- Reasons: climate stability, high productivity, long evolutionary time, less glaciation.
Species-area relationship (Alexander von Humboldt)
- S = CA^Z → log S = log C + Z log A
- Slope Z: 0.1–0.2 (small areas) ; 0.6–1.2 (continents)
Extinction facts
- Current rate: 100–1000× natural rate.
- Sixth mass extinction underway.
- IUCN Red List 2004: ~15,500 species threatened.
HIPPO — causes of biodiversity loss
- Habitat loss & fragmentation (biggest)
- Invasive alien species (Lantana, Eichhornia, African catfish)
- Pollution
- Population (human)
- Overexploitation
Reasons to conserve
| Type | Argument |
|---|
| Narrowly utilitarian | Food, medicine, timber, fibre |
| Broadly utilitarian | Ecosystem services (climate, O₂, water) |
| Ethical | Every species has right to exist |
Amazon supplies ~20% of world's O₂.
In-situ vs Ex-situ
| In-situ (in habitat) | Ex-situ (outside habitat) |
|---|
| Biosphere reserves | Zoos |
| National parks | Botanical gardens |
| Wildlife sanctuaries | Seed banks / Gene banks |
| Sacred groves | Cryopreservation (−196°C) |
India's numbers
- Biosphere reserves: 18
- National parks: 100+
- Wildlife sanctuaries: 500+
- 3 biodiversity hotspots: Western Ghats + Sri Lanka, Eastern Himalayas, Indo-Burma.
- Total global hotspots: 34.
Sacred groves
- Khasi & Jaintia Hills (Meghalaya).
- Aravalli Hills (Rajasthan).
- Western Ghat regions.
- Sarpakavus (Kerala).
- Protected by cultural/religious tradition.
Important species examples
- Rauwolfia serpentina — reserpine (blood pressure).
- ***Taxus* — taxol** (anti-cancer).
- ***Cinchona* — quinine** (malaria).
- Dodo — extinct (Mauritius).
- Passenger pigeon — extinct.
Key events
- Earth Summit 1992 (Rio) — Convention on Biological Diversity.
- Johannesburg Summit 2002 — 190 countries pledged.
FAQ traps
- Who coined "biodiversity"? — Term popularised by Edward Wilson.
- Estimated total species (Robert May)? — 7 million.
- Which is the biggest cause of biodiversity loss? — Habitat loss/fragmentation.
- Where in India are sacred groves prevalent? — Meghalaya (Khasi/Jaintia).
Pocket Notes — Biodiversity and Conservation
3 levels of biodiversity
- Genetic — variation within a species (e.g. Rauwolfia alkaloid content).
- Species — number of species in a region.
- Ecosystem — variety of ecosystems.
Numbers to memorise
- Described species: ~1.5 million
- Robert May's estimate: ~7 million total
- Insects: 70% of animals
- Animals in total species: ~70%
- Plants (incl. algae, fungi): ~22%
- India = 2.4% of land, ~8% of world's species.
Latitudinal gradient
- Species diversity maximum at equator, decreases toward poles.
- Reasons: climate stability, high productivity, long evolutionary time, less glaciation.
Species-area relationship (Alexander von Humboldt)
- S = CA^Z → log S = log C + Z log A
- Slope Z: 0.1–0.2 (small areas) ; 0.6–1.2 (continents)
Extinction facts
- Current rate: 100–1000× natural rate.
- Sixth mass extinction underway.
- IUCN Red List 2004: ~15,500 species threatened.
HIPPO — causes of biodiversity loss
- Habitat loss & fragmentation (biggest)
- Invasive alien species (Lantana, Eichhornia, African catfish)
- Pollution
- Population (human)
- Overexploitation
Reasons to conserve
| Type | Argument |
|---|
| Narrowly utilitarian | Food, medicine, timber, fibre |
| Broadly utilitarian | Ecosystem services (climate, O₂, water) |
| Ethical | Every species has right to exist |
Amazon supplies ~20% of world's O₂.
In-situ vs Ex-situ
| In-situ (in habitat) | Ex-situ (outside habitat) |
|---|
| Biosphere reserves | Zoos |
| National parks | Botanical gardens |
| Wildlife sanctuaries | Seed banks / Gene banks |
| Sacred groves | Cryopreservation (−196°C) |
India's numbers
- Biosphere reserves: 18
- National parks: 100+
- Wildlife sanctuaries: 500+
- 3 biodiversity hotspots: Western Ghats + Sri Lanka, Eastern Himalayas, Indo-Burma.
- Total global hotspots: 34.
Sacred groves
- Khasi & Jaintia Hills (Meghalaya).
- Aravalli Hills (Rajasthan).
- Western Ghat regions.
- Sarpakavus (Kerala).
- Protected by cultural/religious tradition.
Important species examples
- Rauwolfia serpentina — reserpine (blood pressure).
- ***Taxus* — taxol** (anti-cancer).
- ***Cinchona* — quinine** (malaria).
- Dodo — extinct (Mauritius).
- Passenger pigeon — extinct.
Key events
- Earth Summit 1992 (Rio) — Convention on Biological Diversity.
- Johannesburg Summit 2002 — 190 countries pledged.
FAQ traps
- Who coined "biodiversity"? — Term popularised by Edward Wilson.
- Estimated total species (Robert May)? — 7 million.
- Which is the biggest cause of biodiversity loss? — Habitat loss/fragmentation.
- Where in India are sacred groves prevalent? — Meghalaya (Khasi/Jaintia).