Study Materials
General Studies - Environment
Biomes
Basics
- Biome: Large ecological region defined by climate, vegetation, fauna, and soil.
- Climate (temperature + precipitation) determines biome boundaries.
- Major terrestrial biomes: Tundra, Forests, Grasslands, Deserts.
TERRESTRIAL BIOMES – COMPARATIVE TABLE
Biome | Climate | Vegetation | Soil Type | Key Fauna / Features |
Tundra (Arctic & Alpine) | Very cold, low precipitation | Mosses, lichens, grasses (no trees) | Permafrost | Reindeer, arctic fox, polar bear; reptiles absent |
Taiga / Boreal Forest | Cold, long winters | Evergreen conifers (pine, spruce, fir) | Podzols (acidic, leached) | Wolf, lynx, bear; low productivity |
Temperate Deciduous (British Type) | Moderate rainfall, cool winters | Oak, beech, elm, birch | Deep podzolic soil | Seasonal leaf fall |
Temperate Rainforest | Cool, very high rainfall | Tall conifers + epiphytes | Rich organic soil | Grizzly bear; mosses & lichens abundant |
Sub-Tropical Deciduous | Warm, humid | Evergreen + deciduous trees | Fertile soils | Eastern China, SE USA |
Steppe / Temperate Grassland | Semi-arid | Short nutritious grasses | Chestnut soils | Low animal diversity |
Mediterranean Biome | Hot, dry summers, mild, wet winters | Small evergreen broad-leaved trees | Thin, rocky | Fire-resistant, xerophytic plants |
Tropical Deciduous (Monsoon Forest) | Seasonal rainfall | Teak, sal, bamboo, neem | Red & laterite soils | Dominant forest type in India |
Savanna (Tropical Wet & Dry) | Distinct wet & dry seasons | Tall grasses + scattered trees | Porous soils | Elephant, giraffe, umbrella-shaped trees |
Tropical Rainforest | Hot & wet year-round | Evergreen, multilayered canopy | Lateritic (leached) | Highest biodiversity; epiphytes |
Desert (Hot & Mid-latitude) | Extremely arid | Xerophytes, cactus, thorny shrubs | Sandy/saline | Long roots, waxy leaves |
AQUATIC ECOSYSTEMS
Classification (Based on Salinity)
- Freshwater (<5 ppt)
- Brackish water (5–35 ppt)
- Marine (≥35 ppt)
Freshwater Ecosystems
- Lentic (still water): lakes, ponds, swamps.
- Lotic (running water): rivers, streams.
Aquatic Organisms (Based on Zone)
- Neuston: air–water interface.
- Periphyton: attached to plants/substrates.
- Plankton: floating (phyto + zoo).
- Nekton: active swimmers.
- Benthos: bottom dwellers.
Limiting Factors of Aquatic Productivity
1. Sunlight
- Light decreases with depth.
- Photic zone: photosynthesis + respiration.
- Aphotic zone: only respiration.
- Turbidity reduces productivity.
2. Dissolved Oxygen (DO)
- Avg freshwater DO: ~10 ppm.
- Warm water → less oxygen solubility.
- DO < 3–5 ppm → organism death.
- Winterkill: fish die due to ice cover blocking photosynthesis.
3. Temperature
- Aquatic organisms have narrow tolerance limits.
- Small temperature changes can be fatal.
MCQs
Q1. Podzol soils are characteristically associated with which biome?
A. Tropical Rainforest
B. Savanna
C. Taiga (Boreal Forest)
D. Mediterranean Biome
Q2. Which of the following biomes is characterised by permafrost and the absence of trees?
A. Steppe
B. Tundra
C. Taiga
D. Temperate Rainforest
Q3. Epiphytes are most commonly associated with which biome?
A. Temperate Deciduous Forest
B. Tropical Rainforest
C. Savanna
D. Desert
