Levels and Importance of Biodiversity
NCERT Class 12 • Biology • Chapter "Biodiversity and Conservation"
Levels and Importance of Biodiversity
Biodiversity is the variety of life on earth at every level, from the genes within a species to the ecosystems that species live in. India is one of the world's mega diverse countries, holding a very large share of global species in a relatively small area.
The Three Levels
- Genetic diversity is the variation within a single species, as in the many varieties of rice, mango and wheat grown in India.
- Genetic diversity is what lets a species adapt when conditions change, so it is the raw material of evolution.
- Species diversity is the variety of different species in a region, and it is the level most people think of as biodiversity.
- Ecosystem diversity is the variety of habitats, from desert and mangrove to alpine meadow and coral reef.
- India has all three in abundance because of its range of climate, relief and soil.
- Species diversity generally increases from the poles towards the equator, which is why tropical regions are richest.
- Diversity also tends to rise with the area of a habitat, so large continuous forests hold more species than fragments.
Why Biodiversity Matters
- Ecological services include oxygen production, pollination, soil formation, nutrient cycling, water purification and climate regulation.
- Economic value comes from food, timber, fibre, fuel, medicine and raw material for industry.
- A very large share of modern medicines is derived from plants, so unknown species may hold future cures.
- Genetic resources in wild relatives of crops carry resistance genes that breeders will need against future pests.
- Cultural and aesthetic value runs through sacred groves, folk traditions, recreation and tourism.
- A diverse ecosystem is more stable and recovers better from drought, disease or other disturbance.
- Biodiversity hotspots are regions with exceptionally high species richness that are also under serious threat.
| Level | What It Covers | Indian Example |
|---|---|---|
| Genetic diversity | Variation within a species | Many varieties of rice and mango |
| Species diversity | Variety of species in a region | Western Ghats species richness |
| Ecosystem diversity | Variety of habitats | Desert, mangrove, alpine meadow |
Biodiversity hotspot — a region with exceptionally high species richness and a high proportion of endemic species that is also under serious threat.
Hindi me samjhein
आनुवंशिक विविधता एक ही प्रजाति के भीतर का अंतर है, जैसे चावल की अनेक किस्में। प्रजाति विविधता किसी क्षेत्र की भिन्न प्रजातियां हैं, और पारितंत्र विविधता आवासों की भिन्नता है।
Exam me kaise aata hai
- Variation within a single species is called — genetic diversity
- Species diversity is highest near the — equator
- A region of high richness under threat is a — biodiversity hotspot
- Which level covers variety of habitats — ecosystem diversity
UPSC/State PSC ke liye
- Genetic diversity matters most for future adaptation, since a genetically uniform crop can be wiped out by a single new disease.
- Species richness rises towards the equator because tropical regions have had a long stable climate and receive more solar energy through the year.
Yahan confuse hote hain
✗ Biodiversity means only the number of species | It also covers genetic and ecosystem diversity | ✓
✗ Diversity is highest at the poles | It is highest in the tropics | ✓
✗ A hotspot simply means a rich region | A hotspot is rich in endemic species and also under serious threat | ✓
Ek nazar me
- Biodiversity has genetic, species and ecosystem levels.
- Diversity increases from the poles towards the equator and with habitat area.
- Its value is ecological, economic, genetic and cultural.
- Hotspots combine high richness with high threat.