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CAIE A-Level Biology A2 17.3 Evolution Questions

Practise evolution questions by explaining gene-pool change, using DNA sequence evidence and tracing allopatric or sympatric routes to reproductive isolation.

Syllabus
2028–2030
Course
Biology 9700
Level
A2

Exam points

  • link evolution to mutations, selection, allele-frequency change and new species formation
  • use DNA or mitochondrial sequence differences to infer relatedness, divergence or ancestry
  • trace allopatric or sympatric isolation to reduced gene flow and reproductive isolation

Covered syllabus points

17.3.1—Evolution through gene pool change17.3.2—DNA evidence for evolution17.3.3—Speciation through genetic isolation

Question 1

[Maximum number: 6]

Variation exists in populations of a species and this may provide the opportunity for evolution to occur.

Question (a)

(a)

Outline the theory of evolution.

[ 3 ]

Question (b)

(b)

The theory of evolution is supported by DNA sequence data.

Explain how DNA sequences are used to show evolutionary relationships between species.

Figure for Question (b) — CAIE A-Level Biology A2
[ 3 ]

Question 2

[Maximum number: 6]

Question (a)

(a)

There are two main aye-aye populations on the island of Madagascar, one in the west and one in the east.

Fig. 1.2 is a map of Madagascar showing the location of the two main populations.

Fig. 1.2

Fig. 1.2

A study into the variation in the DNA nucleotide sequence of aye-ayes showed that there is a large genetic difference between the west population and east population. The two populations of aye-ayes may be evolving into separate species.

[ 6 ]

Question (i)

(i)

With reference to Fig. 1.2, suggest why there is a large genetic difference between the two populations.

[ 5 ]

Question (ii)

(ii)

Name the type of speciation that is most likely to occur.

[ 1 ]
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