CourseCourseConceptConceptDocumentDocument

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

  • Explain how changing gene pools over generations can produce new species from existing populations.
  • Use DNA sequence differences, databases or bioinformatics to infer common ancestry and relatedness.
  • Use mutation rates in DNA or mtDNA as a molecular clock to estimate when lineages diverged.
  • Interpret generation-time data to explain differences in the rate of evolution.
  • Distinguish allopatric from sympatric speciation using geographic, ecological or behavioural evidence.
  • Trace isolation from reduced gene flow through population divergence to reproductive isolation.
  • Compare pre- and post-zygotic barriers using mating behaviour, hybrid fertility or offspring survival.

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: 3]

Green lacewings are a family of insects with more than 1300 species.

The common green lacewing, Chrysoperla carnea, is shown in Fig. 9.1.

Fig. 9.1

Fig. 9.1

Two species of green lacewing, C. carnea and C. downesi, evolved from a common ancestor. The two species have populations with overlapping distributions in parts of North America.

Table 9.1 shows a comparison of the characteristics of overlapping populations of the two species.

Table 9.1

Table 9.1

Suggest how speciation occurred to produce the two different species of green lacewing.

All question bank results loaded