AQA GCSE Combined Science: Trilogy Biology Paper 2 (Foundation), 2020: Question 5
10 marks · Standard Demand difficulty · Short Answer
This question assesses understanding of biodiversity, ecological sampling methods, and the impact of environmental changes on plant and invertebrate populations.
Practise this questionQuestion
Question text
05 This question is about biodiversity.
A farmer:
• grows only wheat crops
• has used all his small fields to make a few large fields
• cuts down trees in his woodlands to burn as fuel.
05.1 What are two ways the farmer could increase biodiversity on his farm?
[2 marks]
Tick ( ) two boxes.
Cut down trees to grow wheat
Plant hedgerows around his fields
Plant many different crops in his fields
Put fences around his fields
Put fertiliser on his wheat crop 17
Students investigated the effect of cutting down trees in the woodland.
This is the method used.
1. Mark out a 10 m by 10 m area where trees have been removed.
2. Place a 1 m × 1 m quadrat at six random positions in the area.
3. Record the number of plant species present.
4. Record the number of invertebrate species seen among dead leaves on the ground.
5. Repeat steps 1 to 4 in an area where there are trees.
05.2 Suggest one improvement the students could make to their method.
[1 mark]
05.3 The students made this prediction:
‘There will be more invertebrate species living in the area where there are trees.’
Explain why the students’ prediction may be correct.
[2 marks]
Table 1 shows the students’ results.
Table 1
Number of plant species Number of invertebrate species
Quadrat
Area with no trees Area with trees Area with no trees Area with trees
18 2 4 10
26 2 3 6
37 0 4 8
46 3 5 14
*175* 20 4 2 9
68 1 6 13
Mean 7 2 4 10
05.4 The students decided that one result was anomalous.
Draw a ring around the anomalous result in Table 1.
[1 mark]
05.5 How does removing trees affect the number of invertebrate species living among the
dead leaves on the ground?
Use Table 1.
[1 mark]
05.6 There were more plant species growing in the area where there were no trees.
Explain why.
[3 marks]
Mark scheme
Show the mark scheme
AO /
Question Answers Extra information Mark
Spec. Ref.
05.1 plant hedgerows around his 1 AO3
fields 4.7.3.6
plant many different crops in 1
his fields
05.2 any one from: 1 AO3
• repeat in each area 4.7.2.1
• do more quadrats (to take RPA 7
more readings)
• count the number of
individuals of each species
• remove leaf litter and search
in tray
• do a timed search of the leaf
litter
• do on the same day or time
of day
05.3 the trees provide habitat(s) or allow described 1 AO2
shelter 4.7.2.1
RPA 7
so (more) food / camouflage / allow places to hide or cooler or 1
shade available wetter environment
05.4 ring drawn around 20 1 AO3
4.7.2.1
RPA 7
05.5 (removing trees) decreases the 1 AO3
number of invertebrate species 4.7.2.1
RPA 7
05.6 (less trees means) more light 1 AO2
4.7.1.2
(and) more water / minerals in 1 4.4.1.1
soil 4.4.1.3
(so) reduced competition 1
OR
(less trees means) more light 13
(1)
(so) (more) photosynthesis (1)
(so) (more) glucose (for growth)
(1)
Total 10
How to answer it
Biodiversity and Ecosystem Investigation
This question assesses your understanding of biodiversity, the impact of human activity on ecosystems, and your ability to evaluate scientific investigations (Required Practical Activity 7). You need to apply ecological knowledge to explain field data and identify improvements to experimental methods.
Part 05.1: Increasing Biodiversity
✅ Correct Answers
- Plant hedgerows around his fields
- Plant many different crops in his fields
💡 Key Knowledge
Biodiversity is the variety of all the different species of organisms on earth. Monocultures (growing only one crop) and removing natural habitats (like trees and hedgerows) significantly reduce biodiversity.
Part 05.2: Improving the Method
🧠 Exam Technique
When asked for an "improvement," think about how to make the data more reliable or accurate. Any of these would score the mark:
- Repeat the investigation in each area.
- Use more quadrats to get a larger sample size.
- Count the number of individuals of each species (rather than just the number of species).
- Use a more thorough method for finding invertebrates (e.g., searching in a tray).
Part 05.3: Explaining Predictions
✅ Model Answer
Trees provide habitats and shelter for invertebrates. This creates a more suitable environment by providing more food, camouflage, or shade (a cooler/wetter environment).
❌ Common Errors
Avoid vague answers like "it's better for them." You must explicitly link the presence of trees to a specific survival factor like food, shelter, or environmental conditions.
Part 05.4: Identifying Anomalies
✅ Correct Answer
Draw a ring around the number 20 in the "Number of plant species / Area with no trees" column (Quadrat 5).
💡 Key Knowledge
An anomaly is a result that does not fit the pattern of the other data. In this table, the other values for "no trees" are 8, 6, 7, 6, 8. The value 20 is significantly higher than the rest.
Part 05.5: Interpreting Data
✅ Correct Answer
Removing trees decreases the number of invertebrate species.
Part 05.6: Explaining Plant Growth
✅ Model Answer
Removing trees allows more light to reach the ground and provides more water/minerals in the soil, which leads to reduced competition between plants.
Alternative logic: More light leads to more photosynthesis, which produces more glucose for growth.
🧠 Exam Technique
This is a 3-mark question. You must provide a logical chain of reasoning. Linking "less trees" to "more light" is the first step; explaining the consequence (less competition or more photosynthesis) is the second and third step.
Topics
Biology · B7: Ecology
Question and mark scheme from the AQA GCSE Combined Science: Trilogy examination, Biology Paper 2 (Foundation), 2020. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.