Question 71
Variation in organisms can be caused by environmental factors as well as genetic variation. For each of the following examples, place a tick (✓) in the correct column to indicate whether the variation described is likely to be caused by genetic variation, environmental factors or both.
| Example of variation | Genetic variation | Environmental factors | Both |
|---|---|---|---|
| Humans can have brown, blue or green eyes. | □ | □ | □ |
| About half the human population is male, half is female. | □ | □ | □ |
| People in some families are more at risk of heart disease than people in other families. However, not every member of ‘high risk’ families has a heart attack and some members of ‘low risk’ families have heart attacks. | □ | □ | □ |
| Cuttings of hydrangea plants grown in soil with different pH values develop flowers with slightly different colours. | □ | □ | □ |
| Some people are tall; others are short. The tall people are not exactly the same height and not all the short people are the same height. | □ | □ | □ |
| Example of variation | Genetic variation | Environmental factors | Both |
|---|---|---|---|
| Humans can have brown, blue or green eyes. | □ | □ | □ |
| About half the human population is male, half is female. | □ | □ | □ |
| People in some families are more at risk of heart disease than people in other families. However, not every member of ‘high risk’ families has a heart attack and some members of ‘low risk’ families have heart attacks. | □ | □ | □ |
| Cuttings of hydrangea plants grown in soil with different pH values develop flowers with slightly different colours. | □ | □ | □ |
| Some people are tall; others are short. The tall people are not exactly the same height and not all the short people are the same height. | □ | □ | □ |
