Fig. 3.1 shows a male red deer, Cervus elaphus. Red deer are herbivores, browsing on low vegetation in forests and on waste land. [Figure 3.1] A history of wild red deer on the western European island of Ireland includes these facts: • Red deer have lived in Ireland for at least 12000 years. • Originally red deer could cross from the neighbouring island of Great Britain to Ireland over a land connection. • A rise in sea levels at the end of the last Ice Age removed this land connection, separating the red deer on the two islands. • In the 1800s the number of red deer in Ireland decreased sharply after the main food crop for the human population failed for several consecutive years. • In the 1900s this decrease in the number of red deer continued as large areas of waste land were drained for agriculture. • By 1960 red deer were nearly extinct in Ireland, restricted to one population, A, of 60 individuals. • Since then protection has allowed population A to increase to over 600 red deer. • Several new red deer populations, B, C and D, have also been established in different parts of Ireland from individuals brought from Great Britain.

1. (a)Use the information given to identify two causes of extinction that may have threatened the survival of red deer in Ireland.[2]
2. (b)Describe how the level of molecular similarity between the red deer in population A and population B can be investigated.[3]
3. (c)Explain why some red deer in population A show unique molecular features that are not found in any of the red deer of populations B, C and D.[3]

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