Scientists hatched eggs from two populations of the same species of chicken. The chicks were kept under the same conditions, except that they received either a standard food ration or an increased food ration.
The table shows the mean body mass of the chickens at 16 weeks.
| Population | Mean body mass with standard food ration in kg | Mean body mass with increased food ration in kg |
|---|---|---|
| R | 1.8 | 2.2 |
| S | 2.7 | 3.1 |
Give the difference in mean body mass between population R and population S when both were given the standard food ration.
Explain what this difference shows about the cause of variation in body mass.
State how new alleles arise.
Explain what the results for the increased food ration show about the causes of variation in body mass.
96 exam-style questions on Edexcel GCSE Biology 3.4 Variation and the Human Genome Project, covering 3.4.1 Causes of variation, 3.4.2 Outcomes of the Human Genome Project, 3.4.3 Genetic variation within a population, and 3.4.4 Effects of genetic mutations on phenotype. Each one has a worked solution and a mark scheme showing where the marks go.