Cpac 1: Daphnia

Question 1

Method

Answer 1

1. Remove 1 Daphnia with a pipette and place it in the given caffeine solution, allowing it 5 minutes to acclimatise.
2. After that pipette the daphnia onto a cavity slide with some cotton wool to absorb excess solution and to immobilise it.
3. Then whilst observing under a microscope, count the number of heartbeats in a minute using a counter (can be in 30 seconds then multiply by 2).
4. Repeat this process using 5 different caffeine solutions, using daphnia of the same species and size to ensure the results are valid and repeat the experiment to ensure reliability of results.