Biodiversity and Conservation
Class 12 · Biology
4 ideas in Class 12 Biology, explained in plain words, with games and quizzes to practise.
Levels and Counts
Part of: Wealth of Life
Genetic, species and ecological diversities stack from Rauwolfia potency to Western Ghats amphibians to Indian biomes. Over 1.5 million species are recorded against May's 7 million estimate; animals exceed 70 per cent with insects over 70 per cent of animals. India holds 8.1 per cent of species on 2.4 per cent of land.
Why it matters. Share arithmetic plus level sorting answers data questions.
Formulas
- Recorded species exceed 1.5 million
- Animals exceed 70 percent, insects 70 percent of animals
- India holds 8.1 percent species on 2.4 percent land
Key words
- Biodiversity
- : Combined diversity at all levels.
- Genetic diversity
- : Variation within one species.
- Species diversity
- : Variety of species in areas.
- Ecological diversity
- : Variety of ecosystems.
- Mega diversity country
- : Nation with huge species share.
Try it in two minutes
- Assign Rauwolfia, Ghats and biomes to levels.
- Multiply 70 per cent twice.
- Weigh India land versus life.
Try at home. Explain why 7 of 10 animals are insects.
Where Life Crowds
Part of: Wealth of Life
Species fall from equator to poles: Colombia counts 1400 birds against Greenland's 56, and Amazon shelters 40000 plants with 125000 invertebrates. Tropics win through time, constancy and energy. Area curves rise steeply then flatten, with log slopes 0.1 to 0.2 locally and 0.6 to 1.2 across continents.
Why it matters. Gradient reading plus slope meaning answers pattern questions.
Formulas
- Log S equals log C plus Z log A
- Z runs 0.1 to 0.2 locally
- Continental Z runs 0.6 to 1.2
Key words
- Latitudinal gradient
- : Diversity falling toward poles.
- Tropics
- : Belt 23.5 N to 23.5 S.
- Niche specialisation
- : Fine roles in constant climates.
- Species-area curve
- : Richness rising with area.
- Z slope
- : Steepness of log richness.
Try it in two minutes
- Order Colombia, New York, Greenland counts.
- Recite three tropical hypotheses.
- Split local from continental Z.
Try at home. Explain why Ecuador beats Midwest plant counts tenfold.
Loss and the Evil Quartet
Part of: Losing Life
Red Lists record 784 extinctions in 500 years with 15500 threatened now, running 100 to 1000 times pre-human rates. Rivet popper warns key-species loss hits hardest. Habitat loss leads the Evil Quartet with over-exploitation, alien invasion like Nile perch erasing 200 cichlids, and co-extinction following.
Why it matters. Number recall plus cause assignment dominates loss questions.
Key words
- Extinction
- : Permanent loss of species.
- Evil Quartet
- : Four human loss causes.
- Habitat fragmentation
- : Splitting homes into pieces.
- Over-exploitation
- : Greedy over-harvest.
- Alien invasion
- : Foreign species taking over.
- Co-extinction
- : Linked species dying together.
Try it in two minutes
- Quote 784, 27 and 15500.
- Rank four causes.
- Match perch, pigeon and dodo.
Try at home. Explain why amphibians face the highest threat share.
Why and How to Conserve
Part of: Saving Life
Narrow use, broad service and ethics justify saving life: 25 per cent of medicines come from plants and Amazon makes a fifth of oxygen. In situ guards whole habitats through 34 hotspots and Indian reserves, parks and groves, while ex situ banks seeds, gametes and zoo stock.
Why it matters. Reason sorting plus method matching closes conservation questions.
Key words
- In situ
- : On-site whole-habitat care.
- Ex situ
- : Off-site special care.
- Hotspot
- : Rich endemic threatened region.
- Endemism
- : Species confined to one region.
- Sacred groves
- : Faith-protected forest tracts.
- Cryopreservation
- : Frozen gamete banking.
Try it in two minutes
- Sort use, service and duty.
- Place hotspots on a map.
- Split home versus away care.
Try at home. Price a hospital oxygen cylinder against Amazon service.
What your child will practise
- Levels and Counts: Ocean Puzzle (Clue Puzzle)
- Levels and Counts: Ocean Quick Fire (Quick Fire)
- Loss and the Evil Quartet: Jungle Puzzle (Clue Puzzle)
- Where Life Crowds: Jungle Quest (Flip and Match)
- Why and How to Conserve: Desert Quick Fire (Quick Fire)
- Quiz: Levels and Counts (8 questions)
- Quiz: Loss and the Evil Quartet (8 questions)
- Quiz: Where Life Crowds (8 questions)
- Quiz: Why and How to Conserve (8 questions)