This field study is carried out on an island where two lizard species live on different coloured rocks. Fig. 1 shows a pale lizard on limestone and a dark l...
Question 1 Report
This field study is carried out on an island where two lizard species live on different coloured rocks. Fig. 1 shows a pale lizard on limestone and a dark lizard on volcanic rock. A student observes from a hide and records attacks by kestrels on clay models of each lizard colour. Ten pale and ten dark models are placed on each rock type for one hour. No real animals are used, so the study does not injure the lizards.
(a) Identify the adaptation that may help a pale lizard on limestone. [1]
(b) Explain how this adaptation can affect survival and offspring. [3]
(c) Use the investigation to suggest which model colour should receive fewer attacks on volcanic rock. [1]
(d) Explain why both colours of model are placed on each rock type. [2]
(e) Give one ethical advantage of using clay models. [1]
Answer Details
(a) Camouflage / colour matching the background [1] (b) The lizard is less visible to predators [1]; it is less likely to be eaten and more likely to survive [1]; survivors can reproduce and pass alleles to offspring [1] (c) Dark model [1] (d) This allows colour to be compared on the same rock background [1]; it shows whether attack rate is due to model colour rather than a difference between sites [1] (e) No real lizard is attacked, injured or killed [1]
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