AQA GCSE Combined Science: Trilogy Biology Paper 2 (Foundation), 2020: Question 2

9 marks · Standard Demand difficulty · Short Answer

This multi-part question explores the fossil record, extinction, and the theory of evolution by natural selection using ammonites and trilobites as case studies.

Practise this question

Question

A multi-part exam question about fossils and evolution. It includes images of an ammonite fossil and a drawing of a living ammonite, a timeline bar chart showing the existence of trilobites and ammonites over millions of years, and a series of diagrams showing ammonite fossils from different time periods. Students are asked to identify how fossils form, explain why scientists are uncertain about soft-bodied organisms, perform calculations based on the timeline, suggest causes for extinction, identify the scientist who proposed natural selection, and interpret fossil evidence for evolution.
Question text

02 Ammonites became extinct millions of years ago.

Figure 2 is a photograph of a fossil ammonite.

.

Figure 3 is a drawing of what scientists think a living ammonite looked like.

Figure 2 Figure 3

02.1 How was the fossil in Figure 2 formed?

[1 mark]

Tick ( ) one box.

The ammonite left traces where it moved.

The ammonite shell was replaced by minerals.

The ammonite was frozen in ice.

02.2 Suggest why scientists are not certain what living ammonites looked like.

[1 mark]

Figure 4 shows when two different types of organism were alive on Earth.

Figure 4

02.3 How many millions of years ago did ammonites become extinct?

Use Figure 4.

[1 mark]

million years

02.4 Trilobites lived on Earth for 270 million years.

Calculate how much longer ammonites lived on Earth than trilobites.

Use Figure 4.

[2 marks]

8 million years

02.5 Suggest two factors which may have caused ammonites to become extinct.

[2 marks]

The fossil record provides evidence for the theory of evolution by natural selection.

02.6 Which scientist proposed the theory of evolution by natural selection?

[1 mark]

Tick ( ) one box.

Carl Linnaeus

Carl Woese

Charles Darwin 9

02.7 Figure 5 shows ammonite fossils from three different time periods.

Figure 5

How do the fossils in Figure 5 give evidence for the theory of evolution by

natural selection?

[1 mark]

Tick ( ) one box.

All fossils have coiled shells.

More recent fossils are bigger.

Older fossils are more simple.

Mark scheme

Show the mark scheme A table showing the mark scheme for the nine-mark question. It lists the correct answers for each sub-question, including specific points for extinction causes and the correct identification of Charles Darwin. It also provides guidance on acceptable alternative answers and notes on marks awarded for calculations.

AO /

Question Answers Extra information Mark

Spec. Ref.

02.1 the ammonite shell was 1 AO2

replaced by minerals 4.6.3.2

02.2 any one from: 1 AO3

• no living ones around now or allow there were no humans 4.6.3.2

during human times living then

• all the soft parts have

decayed

• the soft parts did not

mineralise / fossilise.

02.3 60 (million years) 1 AO2

4.6.3.3

02.4 (ammonites) 420 - 60 = 360 1 AO2

4.6.3.3

360 - 270 = 90 (million years) 1

allow ecf from question 02.3

02.5 any two from: ignore pollution 2 AO1

4.6.3.3

• drought

• ice age / global warming ignore temperature change

unqualified

• volcanic activity allow earthquake / tsunami

• asteroid / meteor collision

• (new) predators allow hunted / eaten by other

animals

• (new) diseases / pathogens

• competition for food allow lack of food

• competition for mates allow isolation or lack of mates

• lack of habitat or habitat

change

if no other mark awarded allow

natural disaster or climate

change or catastrophic event for

1 mark

02.6 Charles Darwin 1 AO1

(1-3) 4.6.3.1

02.7 older fossils are more simple 1 AO3

4.6.3.2

Total 9

How to answer it

Low Demand

Study Guide: Fossils and Evolution

What this question tests:

This question assesses your understanding of how fossils are formed, why the fossil record is incomplete, how to interpret data from timelines, and your knowledge of the theory of evolution by natural selection.

Question 02.1: Fossil Formation

Correct Answer

The ammonite shell was replaced by minerals.

Key Knowledge

Fossils are the remains of organisms from millions of years ago, found in rocks. Mineral replacement occurs when hard parts of an organism (like shells or bones) are slowly replaced by minerals as they decay, eventually turning into rock.

Question 02.2: Limitations of the Fossil Record

Key Knowledge

Scientists cannot be 100% sure about the appearance of extinct creatures because soft body parts (like tentacles or skin) rarely fossilise. They decay before they can be preserved.

Common Errors

Students often lose marks by being too vague. Avoid saying "they were destroyed." Instead, specify that soft parts decayed or did not mineralise.

Question 02.3 & 02.4: Data Interpretation and Calculation

Step-by-Step Calculation (02.4)

  1. Identify Ammonite lifespan: From Figure 4, ammonites lived from 420 million years ago to 60 million years ago. 420 - 60 = 360 million years.
  2. Compare to Trilobites: Trilobites lived for 270 million years.
  3. Find the difference: 360 - 270 = 90 million years.

Exam Technique

Always use the scale on the graph carefully. If you misread the start or end point of the bars, you will lose marks. Use a ruler to line up the edges of the bars with the axis.

Question 02.5: Causes of Extinction

Key Knowledge

Extinction happens when there are no remaining individuals of a species. Common factors include:

  • Environmental changes (e.g., ice age, volcanic activity).
  • Catastrophic events (e.g., asteroid collision).
  • Biological factors (e.g., new predators, new diseases, or competition for food/mates).

Question 02.6: Theory of Evolution

Correct Answer

Charles Darwin.

Exam Technique

This is a recall question. Ensure you distinguish between Charles Darwin (Natural Selection) and Carl Linnaeus (Classification system).

Question 02.7: Evidence for Evolution

Correct Answer

Older fossils are more simple.

Key Knowledge

The fossil record shows that organisms have changed over time. Generally, the deeper (older) the rock layer, the simpler the organisms found within it, supporting the theory that complex life evolved from simpler ancestors.

Topics

Biology · B6: Inheritance, Variation and Evolution

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.