Natural Selection a Case Study – Post Lesson Practice

Copy and complete the following sentences.

1. Peppered moths occur naturally in two varieties ____________

and melanic. They rely on _______________ to avoid being eaten

by __________________. (3)

2. On light coloured surfaces covered in ___________ the

speckled variety has an advantage over the melanic. With black,

sooty surfaces the opposite is true so the __________ variety is more

common in such areas. (2)

3. Before the industrial revolution the speckled variety was more

common as the melanic variety failed to __________ to pass on its

___________. Since then the increase in pollution caused by burning

_________ has caused lichen to die and surfaces to darken. This has increased the

_____________ chances of melanic moths. Because the two varieties still interbreed,

they remain a single __________. (5)

Total = 10