Biomes — AQA A-Level Geography
Test yourself on Biomes with AQA A-Level practice questions.
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Biomes explained
A biome is a large-scale, global ecosystem characterised by specific climatic conditions and distinct climax vegetation communities.
Read the full explanation
The global distribution of major terrestrial biomes, such as tropical rainforests, savannahs, temperate deciduous forests, and tundra, is primarily dictated by latitude, which influences insolation, temperature, and precipitation patterns. For instance, tropical rainforests are concentrated near the equator where low pressure systems provide abundant, year-round rainfall and high temperatures. Conversely, deserts typically align with the descending dry air of the Hadley cells around 30 degrees north and south. Secondary factors like altitude and continentality also modify these broad latitudinal bands.
The nature of two contrasting biomes: tropical rainforest and savanna grassland to include: the main characteristics of each biome; ecological responses to the climate, soil and soil moisture budget – adaptations by flora and fauna; human activity and its impact on each biome; typical development issues in each biome to include changes in population, economic development, agricultural extension and intensification, implications for biodiversity and sustainability.
Tropical rainforests and savanna grasslands offer contrasting biome characteristics. Rainforests feature high year-round precipitation, creating a moisture surplus supporting rapid nutrient cycling in latosols. Flora adapt with drip tips, while fauna occupy distinct canopy niches. Conversely, savannas experience distinct wet and dry seasons, causing a fluctuating soil moisture budget. Savanna flora like baobab trees store water, and fauna migrate to track rainfall. Human activities impact both: rainforests face deforestation for economic development and agricultural extension, while savannas suffer overgrazing and agricultural intensification driven by population growth. These development issues threaten biodiversity and sustainability.
Your focus
- Define the concept of a biome and distinguish it from smaller-scale ecosystems.
- Map and describe the global distribution of major terrestrial biomes using appropriate geographical terminology.
- Explain how global climate patterns and atmospheric circulation dictate the location of terrestrial biomes.
Show all 6 objectives
- Describe the main climatic and soil characteristics of tropical rainforests and savanna grasslands.
- Explain how flora and fauna adapt to the specific climate, soil, and soil moisture budgets of each biome.
- Analyse the impact of population changes, economic development, and agricultural practices on biodiversity and sustainability.
Biomes exam tips
Marking Points
- Define a biome accurately as a large-scale ecosystem characterised by its dominant vegetation and climate.
- Describe the global distribution of at least three major terrestrial biomes using specific latitudinal references.
- Explain the role of global atmospheric circulation, such as the Hadley, Ferrel, and Polar cells, in determining biome distribution.
- Account for anomalies in latitudinal distribution by referencing local factors such as ocean currents, continentality, and altitude.
- Compare the climate and soil moisture budgets of both biomes, noting the year-round surplus in rainforests versus the seasonal deficit in savannas.
- Explain specific flora and fauna adaptations to climate and soil, such as deep taproots in savanna trees or epiphytic growth in rainforests.
- Evaluate how population growth and economic development drive agricultural extension and intensification in these biomes.
- Assess the implications of human activity on biodiversity loss and the sustainability of ecosystem services in both biomes.
Examiner Tips
- 💡Memorise a global map of major terrestrial biomes and be prepared to describe their distribution using specific lines of latitude.
- 💡When explaining distribution, always link the location of the biome back to the climatic factors that allow its dominant vegetation to thrive.
- 💡Be ready to discuss how the boundaries of these biomes might shift under future climate change scenarios.
- 💡Use specific examples of flora and fauna adaptations for both biomes to support your explanations of ecological responses.
- 💡When discussing development issues, explicitly link population changes to specific agricultural practices like overgrazing or cash-crop expansion.
- 💡Always evaluate the sustainability of human impacts, weighing short-term economic gains against long-term biodiversity losses.
Common Mistakes
- Error: Using the terms 'biome' and 'ecosystem' interchangeably. Correction: Define a biome as a macro-scale classification of similar ecosystems across the globe, whereas an ecosystem can be of any size.
- Error: Describing biome distribution using vague geographical terms like 'hot places'. Correction: Use precise geographical terminology, such as specific latitudes, tropics, or global atmospheric circulation cells.
- Error: Ignoring the influence of precipitation and focusing solely on temperature. Correction: Emphasise that both temperature and precipitation are the primary climatic determinants of terrestrial biomes.
- Error: Confusing agricultural extension with intensification. Correction: Extension refers to increasing the area of farmed land, whereas intensification means increasing the yield per unit area using inputs like fertilisers.
- Error: Assuming savanna soils are identical to rainforest latosols. Correction: While both can be heavily leached, savanna soils often have a distinct laterite crust formed by intense evaporation during the dry season.
- Error: Stating that rainforest soils are highly fertile. Correction: Rainforest soils are actually nutrient-poor; the high productivity relies on rapid nutrient cycling in the biomass rather than soil stores.