Land Use and Deforestation
Revise Land Use and Deforestation for GCSE Biology with this free worksheet and full mark scheme — Foundation and Higher exam-style questions with worked answers for AQA, Edexcel and OCR. Humans reduce the land available to other organisms through building, farming, quarrying and dumping waste.
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These worksheets and mark schemes are original, written for Virtus Academy and checked against the current AQA, Edexcel and OCR specifications. Every worksheet comes with a full mark scheme.
Topic overview
Humans use land for building, quarrying, farming and dumping waste, all of which reduce the land available for other organisms.
The destruction of peat bogs is a particular concern. Peat is decayed plant material that has built up over thousands of years in waterlogged, acidic conditions where decay is slow. Peat bogs are drained and the peat is used as compost, which destroys the habitat and reduces biodiversity.
When peat is removed and decays, or is burned, the carbon it stores is released as carbon dioxide, contributing to global warming. Large-scale deforestation in tropical areas has occurred to provide land for cattle and rice fields and to grow crops for biofuels, reducing biodiversity and releasing further carbon dioxide.
Revision notes
Peat destruction
Peat forms from plant material that has only partly decayed in waterlogged, acidic conditions over thousands of years.
Peat bogs are drained so the peat can be cut and used as compost. This destroys the habitat of the plants, animals and microorganisms living there, reducing biodiversity.
Peat and carbon dioxide
The carbon stored in peat is released as carbon dioxide when the peat is burned or when microorganisms decompose it after drainage.
This contributes to global warming, so peat destruction has an impact well beyond the local habitat.
Deforestation
Large-scale deforestation in tropical areas has occurred to provide land for cattle and rice fields and to grow crops for biofuels.
It reduces biodiversity, reduces the rate at which carbon dioxide is removed by photosynthesis, and releases carbon dioxide from burning and from decomposition of felled trees.
Key points
- Peat is partly decayed plant material formed over thousands of years.
- Peat forms in waterlogged, acidic conditions where decay is slow.
- Draining peat bogs destroys habitats and reduces biodiversity.
- Decaying or burning peat releases carbon dioxide.
- Deforestation provides land for cattle, rice and biofuel crops.
- Deforestation reduces carbon dioxide uptake by photosynthesis.
Worked examples
Example 1
Explain why the destruction of peat bogs reduces biodiversity. [2 marks]
Model answer
Draining the bog destroys the habitat of the plants, animals and microorganisms that live there (1 mark), so those species can no longer survive in that area and the variety of species falls (1 mark).
Example 2
Explain why removing peat contributes to global warming. [2 marks]
Model answer
The peat contains stored carbon (1 mark), which is released as carbon dioxide when the peat is burned or decomposed by microorganisms after drainage (1 mark).
Example 3
Give two reasons large-scale deforestation has taken place in tropical areas. [2 marks]
Model answer
To provide land for cattle and rice fields (1 mark), and to grow crops from which biofuels can be produced (1 mark).
Common mistakes
Saying peat forms quickly.
It takes thousands of years, which is why its loss is effectively permanent.
Forgetting the carbon dioxide link.
Peat destruction is both a biodiversity and a global warming issue.
Giving only one reason for deforestation.
Cattle, rice fields and biofuel crops are all required.
Not explaining why decay is slow in a bog.
Waterlogged, acidic conditions limit the microorganisms that cause decay.
Exam tips
- Explain peat formation through slow decay in waterlogged conditions.
- Give both the biodiversity and carbon dioxide consequences.
- Learn the three reasons for tropical deforestation.
- Link deforestation to reduced photosynthesis as well as released carbon.
Key terms
- Peat
- Partly decayed plant material formed in waterlogged conditions.
- Peat bog
- A wetland habitat where peat accumulates.
- Deforestation
- The large-scale removal of forest.
- Biofuel
- A fuel made from crops grown for the purpose.
Related topics
Written and reviewed against the current AQA, Edexcel and OCR specifications. Spotted an error? Let us know.