The wall gecko shows phenotypic diversity (lines 1–2).

Suggest two factors that have resulted in this phenotypic diversity.

1

2

The ability of diurnal geckos to change skin colour (lines 7–8) is advantageous.

Explain why.

The scientists concluded that it was probable that disruptive selection was leading to sympatric speciation in the wall gecko.

Use the information in the passage to evaluate this conclusion.

Explain how comparison of mitochondrial genes could indicate that the nocturnal geckos formed a distinct genetic group (lines 9–10).

In your answer, explain how new techniques enable the comparison of genes to be completed rapidly.

Describe and explain two precautions required to ensure that the estimate of the size of the population of geckos was valid (lines 12–13).

Do not include sample size as one of the required precautions.

In your answer, include the formula to estimate the size of the population using the mark-release-recapture method.

Precaution 1

Precaution 2

Formula