Variation — practice question

Fig. 3.1 depicts a male red deer, Cervus elaphus. Red deer are herbivores that browse low-growing vegetation in forests and on waste land. A summary of the wild red deer population on the western European island of Ireland includes the following points: - Red deer have been present in Ireland for at least 12000 years. - At first, red deer were able to move from the neighbouring island of Great Britain into Ireland across a land connection. - When sea levels rose at the end of the last Ice Age, this land connection disappeared, leaving the red deer on the two islands separated. - During the 1800s, the number of red deer in Ireland fell rapidly after the main food crop for the human population failed for several years in succession. - In the 1900s, the decline in red deer numbers continued because large areas of waste land were drained for agriculture. - By 1960, red deer were almost extinct in Ireland and remained only in one population, A, with 60 individuals. - Protection since then has allowed population A to rise to more than 600 red deer. - A number of new red deer populations, B, C and D, have also been founded in different parts of Ireland from animals brought in from Great Britain.