Exam Focus

🎯 Exam Focus

Very Frequently Examined

Biodiversity and human impacts appear regularly on AQA Paper 2, often linked to ecology, carbon cycle, and global warming questions. Key question patterns:

• "State two ways humans reduce biodiversity" (2 marks) — name two specific activities (deforestation, pollution, peat destruction, land use change) and briefly state how each reduces biodiversity.
• "Explain how deforestation increases atmospheric CO₂" (3 marks) — trees store carbon → burning/rotting releases CO₂ → fewer trees means less photosynthesis → net CO₂ increase. Link each step.
• "Explain how peat bog destruction contributes to global warming" (3-4 marks) — peat stores carbon → draining allows aerobic decomposers to break it down → CO₂ released → enhanced greenhouse effect → global warming.
• "Describe three methods used to maintain biodiversity" (3 marks) — name three conservation methods and state what each does.
• 6-mark extended questions — often ask to evaluate the effectiveness of conservation methods, or to explain the full chain from deforestation → global warming → biodiversity loss.

Common mark-losing errors: Describing deforestation effects without linking to CO₂; failing to mention both the destruction of habitat AND the release of CO₂ from peat bogs; listing conservation methods without explaining what they achieve; confusing eutrophication with acid rain.

Edexcel 1BI0 Paper 2 (T9 — Ecosystems and Material Cycles): Edexcel biodiversity questions typically present data tables comparing species richness or Simpson's Index values across different sites or over time, asking you to describe the trend and suggest explanations. Questions on human impacts may provide maps or satellite images of deforestation, asking you to calculate percentage change in forest cover and evaluate the effect on biodiversity. "Evaluate" questions on conservation methods ask for advantages and disadvantages with a reasoned conclusion. Edexcel mark schemes use "Accept…" and "Allow…" for equivalent descriptions of habitat loss and species loss mechanisms.