QUESTION 10 (5 marks)
The chart shows the number of families in nine classes of vertebrate (A to I) over geological time.
a) Identify a trend in vertebrate biodiversity over time. Refer to data to support your response.
[2 marks]
b) Identify which classes became extinct during this time and the era/s in which the extinctions occurred.
[2 marks]
c) Which class had family extinctions at the boundary of the Mesozoic and Cenozoic eras?
[1 mark]
QCAA guide · typeset solution
QCAA sample response and mark allocation
10a) | Vertebrate biodiversity has increased over geological time. While the number of different classes has remained about the same in each era (7), the number of families has gradually increased from ~110 at the end of the Palaeozoic era to ~220 at the end of the Mesozoic era and ~610 in the Cenozoic era. | • identifies an appropriate trend [1 mark] • provides data to support response [1 mark] |
10b) | Classes C and D became extinct during the Palaeozoic era. | • identifies C and D [1 mark] • identifies Palaeozoic era [1 mark] |
10c) | Class G | • identifies G [1 mark] |
QCAA sample response and marking criteria reproduced from the official guide.
Compare your working with the guide above.