Ecology and the Environment

Worked examples (5)

• 1Defining ecological terms (4 marks, Paper 1)
• 2Adaptations of a cactus to a desert habitat (4 marks, Paper 1)
• 3Estimating a plant population using quadrats (5 marks, Paper 2)
• 4Mark-release-recapture for woodlice (5 marks, Paper 2)
• 5Belt transect on a rocky shore (4 marks, Paper 2)

Model answers (4)

• ✓Model answer — Adapted from 4BI1/2B January 2024 Q5(a)
• ✓Model answer — Adapted from 4BI1/2B May/Jun 2024 Q3
• ✓Model answer — Adapted from 4BI1/2B January 2024 Q5
• ✓Model answer — Adapted from 4BI1/1B May/Jun 2024 Q6(c)

Worked examples (5)

• 1Identifying trophic levels in a food chain (3 marks, Paper 1)
• 2Why energy decreases at each trophic level (5 marks, Paper 1)
• 3Calculating efficiency of energy transfer (3 marks, Paper 2)
• 4Drawing a pyramid of biomass (4 marks, Paper 2)
• 5Implications for human food production (4 marks, Paper 1)

Model answers (4)

• ✓Model answer — Adapted from 4BI1/2B May/Jun 2024 Q4(a)
• ✓Model answer — Adapted from 4BI1/2B January 2024 Q6(c)
• ✓Model answer — Adapted from 4BI1/2B May/Jun 2024 Q4(b)
• ✓Model answer — Adapted from 4BI1/1B May/Jun 2024 Q7(c)

Worked examples (5)

• 1Identifying processes in the carbon cycle (4 marks, Paper 1)
• 2Naming bacteria in the nitrogen cycle (5 marks, Paper 2)
• 3Why farmers drain waterlogged soil (4 marks, Paper 2)
• 4Carbon cycle from atmosphere to consumer (5 marks, Paper 2)
• 5Factors affecting decomposition rate (4 marks, Paper 2)

Model answers (4)

• ✓Model answer — Adapted from 4BI1/2B May/Jun 2024 Q5
• ✓Model answer — Adapted from 4BI1/2B January 2024 Q7
• ✓Model answer — Adapted from 4BI1/2B May/Jun 2024 Q5(c)
• ✓Model answer — Adapted from 4BI1/2B January 2024 Q6(b)

Worked examples (5)

• 1The greenhouse effect — mechanism (5 marks, Paper 1)
• 2Eutrophication — the full chain (6 marks, Paper 1)
• 3Effects of deforestation (5 marks, Paper 2)
• 4Conservation methods compared (4 marks, Paper 2)
• 5Naming greenhouse gases and their sources (4 marks, Paper 1)

Model answers (4)

• ✓Model answer — Adapted from 4BI1/2B May/Jun 2024 Q7(a)
• ✓Model answer — Adapted from 4BI1/2B January 2024 Q8(c)
• ✓Model answer — Adapted from 4BI1/2B May/Jun 2024 Q6(c)
• ✓Model answer — Adapted from 4BI1/2B January 2024 Q8(d)