📌 CDS Focus: Lower weightage but important. Focus on biome identification by characteristics (which biome has which rainfall, temperature, vegetation), Indian soil types (black soil = cotton; alluvial = fertile plains; laterite = leaching), biodiversity hotspots in India, and conservation terminology (biosphere reserves, national parks, wildlife sanctuaries). Questions are factual and matching-type.
1. World Biomes
Fig. 1.1 — World Biomes: Latitude Band Distribution (Equator to Pole)
Reindeer, musk ox, arctic fox; no trees; extremely short growing season
💡 Grassland Names by Region: Prairie (N. America) · Steppe (Central Asia/Europe) · Pampas (S. America) · Veldt / Veld (S. Africa) · Downs (Australia) · Pradera (Argentina). All are temperate grasslands. Savanna is tropical grassland (Africa/India). A very common CDS matching question.
SOILS OF INDIA
2. Soil Types of India
Fig. 2.1 — Indian Soil Types: Region, Colour & Crop Association
⚠️ Soil Traps: (1) Black soil (Regur) = Cotton soil — forms from Deccan Trap basalt; found in Deccan Plateau (Maharashtra, MP, AP, Gujarat). (2) Laterite soil = highly leached; good for tea/coffee; found in high-rainfall areas (Kerala, Karnataka). (3) Alluvial soil = most fertile and most widespread in India (Indo-Gangetic Plain). (4) Red soil gets its colour from iron oxide (Fe₂O₃). (5) Black soil is self-ploughing — cracks in dry weather, swells in wet weather.
BIODIVERSITY & CONSERVATION
3. Biodiversity, Hotspots & Conservation
Topic CBiodiversity Hotspots in IndiaCDS Direct
A biodiversity hotspot is a region with exceptionally high species richness and endemism that is also significantly threatened by habitat loss. To qualify, a region must have >1,500 endemic plant species and have lost >70% of its original vegetation. India has 4 biodiversity hotspots:
1
Western Ghats & Sri Lanka — Highly endemic flora and fauna; high rainfall; rich in amphibians and endemic plants. Known as the "Land of Spices."
2
Himalayas — Spans from E. Afghanistan to Bhutan; diverse altitudinal zones; many endemic species; includes temperate and alpine ecosystems.
3
Indo-Burma — Includes NE India, Myanmar, Thailand; one of the most threatened hotspots; extremely rich in fish, reptiles, turtles.
4
Sundaland
Sundaland — Includes Andaman & Nicobar Islands (Indian part); Malay Peninsula, Borneo, Sumatra, Java. Rich coral reefs and tropical forests.
🏛️ Conservation Categories
National Parks — Highest protection; no human activity; entry only with permission. e.g., Jim Corbett, Kaziranga
Wildlife Sanctuaries — Some human activity permitted (grazing, forest use). e.g., Bharatpur
Biosphere Reserves — Largest conservation units; include core zone (protected), buffer zone (research), transition zone (human use). e.g., Nilgiri (India's first), Sundarbans
Tiger Reserves — Under Project Tiger (1973); India has 54 tiger reserves
🦁 Key Indian Wildlife
Kaziranga NP (Assam) — One-horned rhinoceros; largest population; UNESCO World Heritage Site
Sundarbans (W. Bengal) — Royal Bengal Tiger; largest mangrove forest; UNESCO WHS
Bharatpur / Keoladeo (Rajasthan) — Migratory birds; UNESCO WHS
Gir NP (Gujarat) — Only wild Asiatic lions in world
Chilika Lake (Odisha) — Largest coastal lagoon in India; Irrawaddy dolphins
Topic DDeforestation & Environment
Causes
Agricultural expansion (main cause globally), logging, mining, urbanisation, infrastructure projects, jhum cultivation (shifting agriculture in NE India).
Effects
Loss of biodiversity; soil erosion; desertification; disruption of water cycle (reduced transpiration and rainfall); contribution to climate change (CO₂ release); displacement of indigenous communities; flooding and landslides.
India Coverage
India's forest cover (as per State of Forest Report): ~21.7% of geographical area. Legal requirement: 33% of land under forest cover (National Forest Policy 1988). Madhya Pradesh has the largest forest area; Lakshadweep has highest % forest cover.
📐 Key Facts Sheet — GC05
Biome — Grassland Names
N. America: Prairie Asia/Europe: Steppe S. America: Pampas S. Africa: Veldt / Veld Australia: Downs
1. Western Ghats & Sri Lanka 2. Himalayas 3. Indo-Burma (NE India) 4. Sundaland (Andaman N.)
Protected Areas
National Park: strictest protection Sanctuary: some human use Biosphere Reserve: core + buffer + transition India's 1st Bio. Reserve: Nilgiri (1986)
Key National Parks
Jim Corbett (Uttarakhand): 1st NP, tigers Kaziranga (Assam): one-horned rhino Gir (Gujarat): Asiatic lions Sundarbans (WB): Royal Bengal Tiger
Key Terms
Endemic species: found only in one region Hotspot criterion: >1,500 endemic plants + >70% habitat lost Taiga = world's largest biome Permafrost = permanently frozen subsoil (Tundra)
📝 Topic-Wise PYQs & Tricky Questions — GC05
Q1. The "Prairie" is a type of grassland found in which region? CDS PYQ
(a) South America(b) Central Asia(c) North America(d) South Africa
✔ Answer: (c) North America
Prairie = temperate grassland of North America (USA/Canada). Other regional names: Steppe (Central Asia/Europe), Pampas (South America), Veldt/Veld (South Africa), Downs (Australia). These are all temperate grasslands, not to be confused with Savanna (tropical grassland, Africa/India).
Q2. Black cotton soil (Regur) in India is formed primarily from: CDS PYQ
(a) Alluvial deposits(b) Decomposition of granitic rocks(c) Weathering of Deccan Trap basalt(d) Leaching of laterite
✔ Answer: (c) Weathering of Deccan Trap basalt
Regur (black cotton soil) forms from the weathering of Deccan Trap volcanic basaltic rock. It is found predominantly in Maharashtra, Madhya Pradesh, Andhra Pradesh, and Gujarat — the Deccan Plateau. It is rich in iron, calcium carbonate, and magnesium. Its key property is self-ploughing — it swells when wet and cracks when dry.
Q3. How many biodiversity hotspots are found in India? CDS PYQ
(a) 2(b) 3(c) 4(d) 5
✔ Answer: (c) 4
India has 4 biodiversity hotspots: (1) Western Ghats & Sri Lanka, (2) Himalayas, (3) Indo-Burma (includes NE India), and (4) Sundaland (includes Andaman & Nicobar Islands). Globally, there are 36 hotspots as identified by Conservation International. India is among the 17 mega-diverse countries.
Q4. The world's largest biome by area is: ⚡ Tricky
The Taiga (Boreal Forest) is the world's largest terrestrial biome, covering large parts of Canada, Russia, and Scandinavia (approximately 17 million km²). Common misconception: Tropical rainforests are the most biodiverse but not the largest. Tundra is the second largest. Taiga is dominated by coniferous trees (pine, spruce, fir) and has very cold winters.
Q5. Which national park is known as the only home of wild Asiatic lions? CDS PYQ
(a) Jim Corbett National Park(b) Kaziranga National Park(c) Gir National Park(d) Bandipur National Park
✔ Answer: (c) Gir National Park
Gir National Park (Gujarat) is the world's only habitat of the Asiatic lion (Panthera leo persica). Jim Corbett (Uttarakhand) was India's first national park, established in 1936, known for tigers. Kaziranga (Assam) is known for one-horned rhinoceros. Bandipur (Karnataka) is a tiger reserve.
Q6. Laterite soil is commonly associated with which type of region and crop? ⚡ Tricky
(a) Arid regions; wheat(b) High rainfall areas; tea and coffee(c) River plains; paddy(d) Volcanic plateau; cotton
✔ Answer: (b) High rainfall areas; tea and coffee
Laterite soil forms in high-rainfall tropical areas where intense leaching washes away soluble minerals, leaving iron and aluminium oxides. Found in Kerala, Karnataka, parts of NE India. The acidic, leached soil is suitable for plantation crops like tea, coffee, and cashew. It is NOT good for food crops without heavy fertilisation.
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