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Exam questions · Biology · Evolution and Natural Selection

Fossil Evidence for Human Evolution

  • 6 exam questions
  • 20 marks
  • 9 quick checks
  1. 1 State [2 marks]

    State two features that the fossil Lucy shows about how her species moved.

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    Model answer

    She walked upright on two legs, shown by her pelvis and knee, and she could still climb trees, shown by her long arms.

    Mark scheme

    • Walked upright — 1 mark
    • Could still climb — 1 mark
  2. 2 State [2 marks]

    State the age of the fossils of (a) Ardi and (b) Lucy.

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    Model answer

    (a) 4.4 million years. (b) 3.2 million years.

    Mark scheme

    • 4.4 million years — 1 mark
    • 3.2 million years — 1 mark
  3. 3 Calculate [3 marks]

    The brain volume of Ardi was 325 cm³ and the brain volume of a modern human is 1350 cm³. Calculate the percentage increase in brain volume. Give your answer to the nearest whole number.

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    Model answer

    The increase is 1350 − 325 = 1025 cm³. The percentage increase is 1025 ÷ 325 × 100 = 315%.

    Mark scheme

    • Increase of 1025 — 1 mark
    • Divide by 325 and multiply by 100 — 1 mark
    • 315% — 1 mark
  4. 4 Describe [3 marks]

    Describe how the brain volume changed from Ardi to the Homo erectus fossils from 1.6 million years ago.

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    Model answer

    The brain volume increased from about 325 cm³ in Ardi to about 400 cm³ in Lucy, and then to about 880 cm³ in Homo erectus. The increase was larger in the later period.

    Mark scheme

    • Increased — 1 mark
    • Values for the fossils — 1 mark
    • Larger increase between Lucy and Homo erectus — 1 mark
  5. 5 Explain [4 marks]

    Explain how the fossils of Ardi and Lucy provide evidence that walking upright evolved before large brains.

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    Model answer

    Both Ardi and Lucy had features such as a pelvis and leg bones that show they could walk upright. Their brain volumes were small, at about 325 and 400 cm³, similar to those of a chimpanzee. So the ability to walk upright was present millions of years before the brain became much larger, as shown by the later Homo erectus.

    Mark scheme

    • Pelvis and leg shape show walking upright — 1 mark
    • Both were old fossils (4.4 and 3.2 million years) — 1 mark
    • Brain was small — 1 mark
    • Large brain appeared later — 1 mark
  6. 6 Evaluate [6 marks]

    Evaluate the use of fossils as evidence for human evolution.

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    Model answer

    Fossils provide direct evidence of the structure of our ancestors. The finds of Ardi, Lucy and the Leakey fossils show a gradual change from small brains and a mixed walk and climb to large brains and an efficient upright walk, over millions of years. The fossils can also be dated, so the order of changes can be worked out. However, the fossil record is incomplete because fossilisation is rare, and many species may be missing. Often only a few bones are found, so scientists can disagree about how to interpret them. The dating methods have some uncertainty. Overall, fossils are strong evidence, particularly when they are supported by DNA evidence.

    Mark scheme

    • Direct evidence of structure — 1 mark
    • Shows gradual change — 1 mark
    • Can be dated — 1 mark
    • Record is incomplete — 1 mark
    • Interpretation is uncertain — 1 mark
    • A reasoned conclusion — 1 mark

Quick check

  1. 1

    Which fossil is about 3.2 million years old?

    1. AArdi
    2. BLucy
    3. CHomo erectus boy
    4. DA modern human
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    B: Lucy

    Lucy lived about 3.2 million years ago.

  2. 2

    Which fossil is the oldest?

    1. AArdi
    2. BLucy
    3. CHomo erectus
    4. DModern human
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    A: Ardi

    Ardi, at about 4.4 million years, is older than Lucy and the Homo erectus fossils.

  3. 3

    What does the pelvis of Lucy show?

    1. AThat she could swim
    2. BThat she was a male
    3. CThat she walked upright
    4. DThat she lived in trees only
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    C: That she walked upright

    The shape of her pelvis shows that she walked upright on two legs.

  4. 4

    Which fossil had the largest brain?

    1. AArdi
    2. BLucy
    3. CA chimpanzee
    4. DHomo erectus
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    D: Homo erectus

    The Homo erectus fossil, with about 880 cm³, had a bigger brain than Lucy or Ardi.

  5. 5

    In which country were Ardi and Lucy found?

    1. AKenya
    2. BEthiopia
    3. CEgypt
    4. DSouth Africa
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    B: Ethiopia

    Both were found in Ethiopia, in East Africa.

  6. 6

    What evolved first in human ancestors?

    1. AWalking upright
    2. BA large brain
    3. CStone tools
    4. DSpeech
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    A: Walking upright

    Fossils such as Ardi and Lucy show that walking upright came before large brains.

  7. 7

    Why is the fossil record incomplete?

    1. AFossils are not real
    2. BFossils are always destroyed by water
    3. CFew organisms become fossils
    4. DScientists do not look for fossils
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    C: Few organisms become fossils

    Fossilisation is rare, so most organisms never form fossils.

  8. 8

    Lucy's brain was 400 cm³ and the Homo erectus boy's was 800 cm³. What is the percentage increase?

    1. A25%
    2. B50%
    3. C200%
    4. D100%
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    D: 100%

    The increase is 400, and \(400 \div 400 \times 100 = 100\%\).

  9. 9

    Scientists sometimes disagree about how a fossil fits into human evolution. Why?

    1. AFossils change over time
    2. BOnly a few bones are often found, so they are hard to classify
    3. CDNA is not found in fossils
    4. DFossils are too young
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    B: Only a few bones are often found, so they are hard to classify

    Often only a few bones are found, so the fossil is hard to classify, and different scientists interpret them differently.