AQA GCSE Combined Science: Trilogy Biology Paper 2 (Foundation), 2024: Question 4
12 marks · Standard Demand difficulty · Short Answer
Answer a series of short questions about evolution, natural selection, extinction, fossils, evolutionary trees and antibiotic resistance in bacteria.
Practise this questionQuestion
Question text
04 Figure 8 shows an evolutionary tree.
Figure 8
04.1 Which species in Figure 8 is most closely related to lions?
[1 mark]
Tick ( ) one box.
Jaguar
Leopard
Snow leopard
04.2 Tigers are more closely related to snow leopards than to jaguars.
Draw a line on Figure 8 to show the evolution of tigers.
Label the line ‘Tiger’.
[1 mark]
04.3 What is represented by species R on Figure 8?
[1 mark]
Tick ( ) one box.
*20* A species recently evolved from jaguars.
A species that may evolve in the future.
A species that the other species evolved from.
04.4 Complete the sentence.
Choose the answer from the box.
[1 mark]
classification homeostasis natural selection
Evolution occurs by the process of .
04.5 Species can become extinct.
Give two possible causes of extinction.
[2 marks]
04.6 Fossils are used to study the evolution of some species.
Suggest one reason why fossils are used to study evolution.
[1 mark]
Some bacteria have evolved to be resistant to penicillin.
Penicillin is an antibiotic.
04.7 How has the process of evolution produced bacteria that are resistant to penicillin?
Write the stages, A, B, C, D and E in the correct order.
The first stage has been completed for you.
[3 marks]
A The bacteria with mutations are more likely to survive.
B The population of bacteria is exposed to penicillin.
C The mutation for resistance to penicillin is passed on to offspring.
D Variation in the population of bacteria is caused by mutation.
E The surviving bacteria reproduce.
D → → 23 → →
04.8 New antibiotics are not likely to control the spread of bacteria that are
resistant to antibiotics.
What are two reasons why?
[2 marks]
Tick ( ) two boxes.
Antibiotics kill all types of bacteria.
Antibiotic resistant bacteria will continue to evolve.
Bacteria reproduce very rapidly.
New antibiotics are cheap to produce.
Testing new antibiotics is quick.
Mark scheme
Show the mark scheme
Question 4
AO /
Question Answers Extra information Mark
Spec. Ref.
04.1 leopard 1 AO2
4.6.4
AO /
Question Answers Mark
Spec. Ref.
04.2 a branch / line drawn at any point between ‘X’ marks, labelled 1 AO3
‘tiger(s)’ 4.6.4
AO /
Spec. Ref.
04.3 a species that the other species 1 AO3
evolved from 4.6.4
AO /
Spec. Ref.
04.4 natural selection 1 AO1
4.6.2.2
4.6.3.1
AO /
Spec. Ref.
04.5 any two from: 2 AO1
4.6.3.3
• drought if none of these awarded
• ice age allow 1 mark for climate
• global warming change 19
ignore weather
• volcanic activity if neither of these awarded
• asteroid collision allow 1 mark for catastrophic
event or natural disaster
• (new) predators allow named example
allow hunters
• (new) disease / pathogen allow named example
• competition for food allow lack of food
• competition for mates allow lack of mates
ignore competition unqualified
• lack of habitat ignore environment change
or habitat change
ignore isolation
ignore pollution
AO /
Spec. Ref.
04.6 any one from: 1 AO1
• if species is extinct 4.6.4
4.6.3.2
• if (fossil) species is unknown
• evolution is (usually) slow
• (fossils) show (evolutionary)
change
ignore fossils are (usually) very
old
20 AO /
Spec. Ref.
04.7 (D) → B → A → E → C 3 AO2
allow 1 mark for link B → A 4.6.3.1
allow 1 mark for link A → E 4.6.3.4
allow 1 mark for link E → C
AO /
Spec. Ref.
04.8 antibiotic resistant bacteria will 1 AO3
continue to evolve 4.6.3.1
4.6.3.4
bacteria reproduce very rapidly 1
Total Question 4 12
How to answer it
Evolution in a family tree
Figure 8: evolutionary tree skills
💡 Key knowledge
- On an evolutionary tree, species that share a more recent common ancestor are more closely related.
- The species at the base/branch point is usually the common ancestor of the others.
- Natural selection is the process by which advantageous traits become more common over time.
🧠 Exam technique
- Read the tree from the branch points, not from the order of the labels.
- For one-mark questions, the exact word in the mark scheme matters.
- When asked to draw a branch, it must connect at a point on the tree and be labelled correctly.
Part 04.1 — Which species is most closely related to lions?
Tick one box. [1 mark]
✅ Correct answer
Leopard
The lion and leopard share the most recent common ancestor on the tree.
❌ Common errors
- Choosing jaguar because it appears near the lion on the diagram.
- Choosing snow leopard because it has “leopard” in the name.
- Missing that relatedness is based on branch points, not just physical closeness on the page.
Part 04.2 — Draw the evolution of tigers
Draw a line on Figure 8 and label it “Tiger”. [1 mark]
✅ What the examiners wanted
A branch/line drawn at any point between the X marks, then labelled “tiger”.
This means the tiger branch should be placed so that tigers are more closely related to snow leopards than to jaguars.
🧠 How to score the mark
- Draw a line from the correct branch point on the tree.
- Make sure the line is clearly labelled.
- Any position between the two marked X points was accepted.
💡 Key knowledge
If species A is more closely related to species B than to species C, A and B share a more recent ancestor than either does with C.
❌ Common errors
- Putting tiger next to jaguar because both are big cats.
- Drawing the branch from the wrong point on the tree.
- Forgetting to label the line.
Part 04.3 — What does species R represent?
Tick one box. [1 mark]
✅ Correct answer
A species that the other species evolved from
💡 Key knowledge
Species R is the common ancestor of the other species shown on the tree.
🧠 Exam technique
In GCSE biology, “evolved from” usually means the ancestor at the base of the tree, not a modern species that changed into another current species.
❌ Common errors
- Choosing “a species recently evolved from jaguars”.
- Choosing “a species that may evolve in the future”.
- Thinking evolution is goal-directed.
Part 04.4 — Complete the sentence
Evolution occurs by the process of _____. [1 mark]
✅ Correct answer
natural selection
💡 Key knowledge
Natural selection means individuals with advantageous features are more likely to survive and reproduce, so those features become more common in the population.
🧠 Exam technique
If you see a sentence like “Evolution occurs by the process of…”, the exact phrase natural selection is usually required.
Part 04.5 — Causes of extinction
Give two possible causes of extinction. [2 marks]
✅ Acceptable answers any two from
- drought
- ice age
- global warming
- volcanic activity
- asteroid collision
- new predators
- new disease / pathogen
- competition for food
- competition for mates
- lack of habitat / habitat change
💡 Key knowledge
Extinction happens when a species can no longer survive and reproduce in its environment.
🧠 Exam technique
Any two correct causes earn the marks. You do not need to explain them unless asked.
❌ Common errors seen by examiners
- Writing vague answers like “weather” or “bad conditions”.
- Giving only one cause twice in different words.
- Writing “competition” without saying for what, when the mark scheme wants a clear example.
Part 04.6 — Why fossils are useful for studying evolution
Suggest one reason. [1 mark]
✅ Correct answers
- if the species is extinct
- if the fossil species is unknown
- evolution is usually slow
- fossils show evolutionary change
💡 Key knowledge
Fossils provide evidence of what organisms looked like in the past, so they can show how species changed over time.
🧠 How to get the mark
A short, clear explanation is enough. For example: “Fossils show evolutionary change over time.”
❌ Common errors
- Writing only “because fossils are old” — this was not the mark point.
- Repeating the question without explaining why fossils help.
- Confusing fossils with DNA evidence.
Part 04.7 — Bacteria resistant to penicillin
Put the stages A, B, C, D and E in the correct order. [3 marks]
✅ Correct order
D → B → A → E → C
Full mark scheme sequence. One mark could be given for each correct linked pair: B → A , A → E , E → C .
💡 Stage meanings
- D: Variation in the population of bacteria is caused by mutation.
- B: The population of bacteria is exposed to penicillin.
- A: The bacteria with mutations are more likely to survive.
- E: The surviving bacteria reproduce.
- C: The mutation for resistance to penicillin is passed on to offspring.
🧠 Exam technique
Use the natural selection story:
- Variation exists first.
- The antibiotic creates a selection pressure.
- Resistant bacteria survive.
- They reproduce.
- Resistance is inherited.
📐 Step-by-step logic
- Mutation creates variation in the population.
- Penicillin is added, so non-resistant bacteria die.
- The resistant bacteria survive.
- The survivors reproduce rapidly.
- The resistance allele/feature is passed to offspring.
❌ Common traps
- Putting the antibiotic before the mutation.
- Forgetting that resistance must be inherited.
- Mixing up survival with reproduction.
Part 04.8 — Why new antibiotics may not control resistant bacteria
Tick two boxes. [2 marks]
✅ Correct answers
- Antibiotic resistant bacteria will continue to evolve.
- Bacteria reproduce very rapidly.
💡 Key knowledge
Resistance can spread quickly because bacteria divide fast and new resistant mutations can keep appearing.
🧠 Why these are the best answers
These points explain why resistance is hard to stop: bacteria can evolve quickly and build up large populations in a short time.
❌ Common errors
- Choosing “antibiotics kill all types of bacteria” — this is false.
- Choosing “new antibiotics are cheap to produce” or “testing is quick” — not relevant to the biology of spread.
- Not linking the answer to rapid growth and evolution.
Quick revision recap
💡 Remember
- Closest relatives share the most recent common ancestor.
- Species R is the common ancestor.
- Evolution happens by natural selection.
- Extinction can be caused by environmental change, disease, predators, or lack of resources.
🧠 Best exam habit
For one-mark biology questions, use the exact wording from the specification where possible: natural selection, common ancestor, resistant bacteria, and rapid reproduction.
Topics
Biology · B6: Inheritance, Variation and Evolution · B3: Infection and Response
Question and mark scheme from the AQA GCSE Combined Science: Trilogy examination, Biology Paper 2 (Foundation), 2024. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.