A species of bird lives on a sub-Antarctic island where the air temperature can fall below −15 °C.
The birds have a thick layer of feathers. When the air temperature falls, they move into tightly packed groups and their bodies automatically reduce the blood flow through the skin of their feet.
There is variation between the birds in their tendency to move into a group. This tendency is affected by alleles.
Scientists measured the mean body temperature of birds kept at an air temperature of −15 °C.
| Position of birds | Mean body temperature at the start in °C | Mean body temperature after one hour in °C |
|---|---|---|
| Alone | 38.5 | 36.4 |
| In a tightly packed group | 38.5 | 38.1 |
State the type of adaptation shown by each of the three features described.
Use the data and the information about alleles to explain how the tendency to move into a tightly packed group could become more common in the population over many generations.
82 exam-style questions on AQA GCSE Biology 7.1 Adaptations, interdependence and competition, covering 7.1.1 Communities, 7.1.2 Abiotic factors, 7.1.3 Biotic factors, and 7.1.4 Adaptations. Each one has a worked solution and a mark scheme showing where the marks go.