A population of frogs contains females with either spotted or plain skin. Different alleles determine these skin patterns. Scientists recorded the females that survived one breeding season and the number of their offspring that survived to adulthood.
| Skin pattern | Number of surviving females | Total number of offspring surviving to adulthood |
|---|---|---|
| Spotted | 36 | 90 |
| Plain | 24 | 60 |
Which statement correctly compares the mean reproductive success of the surviving females?
Spotted females have greater mean reproductive success because 90 offspring survived to adulthood.
Mean reproductive success cannot be compared because different numbers of females survived.
Both groups have the same mean reproductive success because 90 ÷ 36 equals 60 ÷ 24.
Plain females have greater mean reproductive success because 60 offspring came from only 24 females.
85 exam-style questions on Edexcel GCSE Biology 4.1 Evolution and natural selection, covering 4.1.1 Work of Darwin and Wallace and 4.1.2 Resistant organisms and evolution. Each one has a worked solution and a mark scheme showing where the marks go.