Water fleas are tiny animals that live in ponds. When conditions are good, female water fleas reproduce asexually.
Scientists recorded the number of water fleas in a pond over three weeks.
The Table shows their results.
Table
| Time in weeks | Number of water fleas |
|---|---|
| 0 | 20 |
| 1 | 60 |
| 2 | 180 |
| 3 | 540 |
Calculate the percentage increase in the number of water fleas from week 1 to week 3.
Explain why asexual reproduction allows the number of water fleas to increase so quickly.
When the pond begins to dry up, the water fleas reproduce sexually. They produce eggs that can survive until the pond fills with water again.
Suggest why it is an advantage that these eggs are produced by sexual reproduction.
40 exam-style questions on Edexcel GCSE Biology 3.1 Reproduction and meiosis, covering 3.1.1 Advantages and disadvantages of reproduction and 3.1.2 Role of meiotic cell division. Each one has a worked solution and a mark scheme showing where the marks go.