Topic 7: 7.1 The Earth is home to a number of very large ecosystems (biomes) the distribution of which is affected by climate and other factors — Edexcel GCSE Geography B
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Topic 7: 7.1 The Earth is home to a number of very large ecosystems (biomes) the distribution of which is affected by climate and other factors explained
Topic 7: 7.1 The Earth is home to a number of very large ecosystems (biomes) the distribution of which is affected by climate and other factors covers 2 specification points, including A.
Read the full explanation
How the global distribution and… and B. Local factors (altitude, rock and soil…. Open a point below for its explanation and revision guidance.
a. How the global distribution and characteristics of major biomes (tropical, temperate and boreal forests, tropical and temperate grasslands, deserts and tundra) are influenced by climate (temperature, precipitation, sunshine hours).
Biomes are large ecosystems whose distribution follows climate: temperature, precipitation and sunshine. Tropical forests are hot and wet all year with high sunshine, lying near the equator. Temperate forests have moderate temperatures and rain spread through the year. Boreal forests have long cold winters and a short growing season. Tundra has very low temperatures and little precipitation. Deserts have very low precipitation and very high sunshine hours. Tropical grasslands have wet and dry seasons; temperate grasslands have cold winters, warm summers and less rain than forests. Link each biome to named climate variables.
b. Local factors (altitude, rock and soil type, drainage) can alter the biome distribution locally and how the biotic (flora, fauna) and abiotic (soils, rock, water, atmosphere) components of biomes interact.
This statement asks how local factors change where biomes occur and how a biome's biotic and abiotic parts interact. Climate sets the broad biome pattern, but altitude, rock and soil type, and drainage create local exceptions. On a mountain, temperature falls with height, so vegetation zones change up the slope within one latitude. Free-draining limestone gives thin, alkaline soils that may suit different plants from clay, while waterlogged ground favours bog plants. Biotic and abiotic parts interact: plant litter decomposes into humus, earthworms mix the soil, and decomposition relies on moisture and atmospheric oxygen. Name one local factor, its effect on the biome, and one interaction.
Your focus
- Identify the typical temperature, precipitation and sunshine conditions of each named biome.
- Explain how a named climate variable influences the characteristics of a specified biome.
- Match each biome to its global location pattern using climate evidence.
Show all 6 objectives
- Identify altitude, rock and soil type, and drainage as local factors that can change biome distribution.
- Explain how a named local factor alters vegetation or biome type within a climate zone.
- Describe one interaction between a biotic component and an abiotic component of a biome.
Topic 7: 7.1 The Earth is home to a number of very large ecosystems (biomes) the distribution of which is affected by climate and other factors exam tips
Marking Points
- Identifies tropical forests as hot and wet all year with high sunshine, located near the equator.
- Describes temperate forests as having moderate temperatures and rainfall spread through the year.
- Explains that boreal forests reflect long cold winters and a short growing season.
- States that tundra has very low temperatures and little precipitation.
- Links deserts to very low precipitation and very high sunshine hours.
- Distinguishes tropical grasslands by a wet and dry season from temperate grasslands with cold winters, warm summers and less rain than forests.
- Identifies altitude, rock and soil type, or drainage as a local factor that modifies the climate-driven biome pattern.
- Explains the mechanism by which the factor works, such as temperature falling with height, rather than only naming it.
- Links a biotic component (flora or fauna) to an abiotic component (soil, rock, water or atmosphere) through a described interaction.
- Describes the direction of the interaction, for example litter returning nutrients to the soil and supporting further plant growth.
- Applies the factor to a specific local change in vegetation or biome type, rather than a general statement about climate.
Examiner Tips
- 💡Create a table with columns for temperature, precipitation and sunshine hours, then complete one row per biome before answering.
- 💡When answering multiple-choice items, eliminate options that describe climate variables incorrectly for a named biome, such as high precipitation for deserts.
- 💡Practise matching each biome to a single climate pattern so you can recall it quickly under timed conditions.
- 💡Name one specific local factor and one specific biome effect in the same sentence so the link is clear.
- 💡Use a biotic-abiotic pair, such as earthworms and soil structure, and state the direction of the effect.
- 💡Check that every answer explains a mechanism, not just a list of factors from the statement.
Common Mistakes
- Treats sunshine hours as the only climate factor, which leaves out temperature and precipitation; correct by naming all three climate variables for each biome.
- Describes biome characteristics without linking them to a climate variable, so the answer does not show influence; correct by stating which variable causes each characteristic.
- Places tundra in warm regions because it is a large biome, which contradicts its very low temperatures; correct by associating tundra with cold high-latitude or high-altitude conditions.
- Confuses tropical grasslands with tropical forests by describing constant rainfall, which ignores the seasonal dry period; correct by stating the wet and dry seasons.
- States that altitude is a climate factor without showing that it changes the local biome; name the resulting vegetation change.
- Treats drainage as a climate variable; correct this by describing it as a local control on water availability in the soil.
- Lists biotic and abiotic components without describing any interaction between them; state how one component affects another.
- Presents local factors as replacing climate entirely; correct this by explaining that they modify the broader climate-driven pattern.