Biomes of the World
Concepts (3)
Taiga = largest terrestrial biome; Tropical Rainforest = highest productivity; Tundra = permafrost defining feature.
Key Facts
- Taiga (Boreal Forest) is the world's largest terrestrial biome by area — extends across northern Canada, Russia (Siberia), and Scandinavia [Source: NCERT Geography Class 11]
- Tropical Rainforest has the highest net primary productivity of all biomes and contains ~50% of Earth's terrestrial species on ~7% of land area [Source: NCERT Biology / WWF]
- Desert biomes (hot and cold): annual rainfall less than 25 cm; Sahara Desert is largest hot desert; Antarctica is the largest cold desert [Source: NCERT Geography]
- Ecotone (edge effect): transition zone between biomes has higher species richness than either adjacent biome alone [Source: NCERT Ecology]
- Mediterranean biome: hot dry summers, cool wet winters; found in California, Mediterranean basin, Chile, SW Australia, Cape region of South Africa — only 5 regions globally [Source: NCERT Geography]
Which biome is characterised by permanently frozen subsoil (permafrost), extremely low temperatures, and dominated by mosses, lichens, and dwarf shrubs?
The Tundra biome is characterised by permafrost, a growing season of only 50-60 days, and vegetation dominated by mosses, lichens, sedges, and dwarf shrubs. It is found in high Arctic latitudes and at high altitudes (alpine tundra).
Consider the following statements about the Tropical Rainforest biome: 1. It receives more than 200 cm of annual rainfall. 2. It shows clear seasonality in temperature. 3. It contains the highest species biodiversity per unit area of any biome. Which of the statements given above is/are correct?
Statements 1 and 3 are correct. Tropical rainforests receive 200-450 cm of annual rainfall. Statement 2 is incorrect — rainforests have minimal temperature seasonality (average 20-28°C year-round); what they show is variation in rainfall between wet and dry periods.
The Savanna biome is primarily characterised by which combination of features?
Savanna is a tropical grassland biome with scattered trees, pronounced wet and dry seasons, 75-150 cm annual rainfall, and frequent natural fires. It is found in sub-Saharan Africa, central Brazil (Cerrado), and northern Australia.
Which of the following biomes has the LOWEST net primary productivity?
The Hot Desert biome (e.g., Sahara, Thar) has the lowest net primary productivity among terrestrial biomes due to extreme water scarcity. Open ocean and tundra also have low productivity, but hot deserts receive even less annual rainfall (less than 25 cm) and have sparse vegetation.
The Boreal Forest (Taiga) biome is primarily composed of which type of vegetation?
The Taiga is dominated by coniferous trees (conifers) such as spruce, fir, pine, and larch. It is the world's largest terrestrial biome by area, stretching across Canada, Russia, and Scandinavia, and is characterised by long cold winters and short warm summers.
Consider the following: 1. Mediterranean Shrubland (Chaparral) 2. Temperate Deciduous Forest 3. Tropical Dry Forest. Which of the above biomes experience a distinct dry season?
All three experience a distinct dry season. Mediterranean shrubland has hot dry summers and mild wet winters. Tropical dry forest has 3-6 dry months per year. Temperate deciduous forests experience reduced moisture in winter. Mediterranean and Tropical Dry Forest dry seasons are more pronounced.
What is the ecological significance of the ecotone between two biomes?
An ecotone is the transition zone between two adjacent biomes or ecosystems. It tends to have higher species diversity than either adjoining community — a phenomenon called the 'edge effect.' The ecotone contains species from both communities plus species unique to the transition zone.
Common Mistakes
- Students confuse Taiga (conifer-dominated, largest terrestrial biome) with Tundra (treeless, permafrost) — Taiga is SOUTH of Tundra; as latitude decreases: Tundra → Taiga → Temperate Forest → Subtropics
- Students say the largest biome is the Tropical Rainforest — the Taiga is actually the largest terrestrial biome by area; the ocean is the largest biome overall
- Students mix up ecotone (transition between biomes) with niche (role of species in ecosystem) — these are entirely different ecological concepts
Savanna is a tropical grassland biome with scattered trees, pronounced wet and dry seasons, 75-150 cm annual rainfall, and frequent natural fires.
Key Facts
- Savanna annual rainfall: 75-150 cm; fire frequency is ecologically essential — suppresses tree establishment and maintains grass dominance [Source: NCERT Geography Class 11]
- Desert biomes (hot and cold): annual rainfall less than 25 cm; Sahara Desert is largest hot desert; Antarctica is the largest cold desert [Source: NCERT Geography]
- Mediterranean biome: hot dry summers, cool wet winters; found in California, Mediterranean basin, Chile, SW Australia, Cape region of South Africa — only 5 regions globally [Source: NCERT Geography]
The Savanna biome is primarily characterised by which combination of features?
Savanna is a tropical grassland biome with scattered trees, pronounced wet and dry seasons, 75-150 cm annual rainfall, and frequent natural fires. It is found in sub-Saharan Africa, central Brazil (Cerrado), and northern Australia.
Which of the following biomes has the LOWEST net primary productivity?
The Hot Desert biome (e.g., Sahara, Thar) has the lowest net primary productivity among terrestrial biomes due to extreme water scarcity. Open ocean and tundra also have low productivity, but hot deserts receive even less annual rainfall (less than 25 cm) and have sparse vegetation.
Consider the following: 1. Mediterranean Shrubland (Chaparral) 2. Temperate Deciduous Forest 3. Tropical Dry Forest. Which of the above biomes experience a distinct dry season?
All three experience a distinct dry season. Mediterranean shrubland has hot dry summers and mild wet winters. Tropical dry forest has 3-6 dry months per year. Temperate deciduous forests experience reduced moisture in winter. Mediterranean and Tropical Dry Forest dry seasons are more pronounced.
Common Mistakes
- Students say deserts have no biodiversity — hot deserts have specialised adapted species; the statement that 'deserts have zero productivity' is an overstatement; correct fact is LOWEST productivity
Taiga = largest terrestrial biome; Tropical Rainforest = highest productivity; Tundra = permafrost defining feature.
Key Facts
- Tundra: permafrost is defining feature; growing season only 50-60 days; CO2 sink threatened as permafrost thaws and releases CH4 (methane) [Source: IPCC AR6]
Which biome is characterised by permanently frozen subsoil (permafrost), extremely low temperatures, and dominated by mosses, lichens, and dwarf shrubs?
The Tundra biome is characterised by permafrost, a growing season of only 50-60 days, and vegetation dominated by mosses, lichens, sedges, and dwarf shrubs. It is found in high Arctic latitudes and at high altitudes (alpine tundra).
Which of the following biomes has the LOWEST net primary productivity?
The Hot Desert biome (e.g., Sahara, Thar) has the lowest net primary productivity among terrestrial biomes due to extreme water scarcity. Open ocean and tundra also have low productivity, but hot deserts receive even less annual rainfall (less than 25 cm) and have sparse vegetation.
Common Mistakes
- Students confuse Taiga (conifer-dominated, largest terrestrial biome) with Tundra (treeless, permafrost) — Taiga is SOUTH of Tundra; as latitude decreases: Tundra → Taiga → Temperate Forest → Subtropics
Ready to practice? Start an interactive lesson.
Start Lesson: Tropical & Temperate Forests