Our experiment was to see whether difference substances would affect the heart rate of Daphnia. The resting heart rate of Daphnia was recorded and they were then placed into ethanol, caffeine or water for 10 minutes and recorded again. We found that as predicted the ethanol slowed the heart rate, caffeine increased the heart rate and the water didn’t affect the heart rate as much. (As shown in the graph below).
This experiment gave us extra knowledge on the anatomy and physiology of the daphnia. It was very interesting to see how their body reacts with different substances such as ethanol and caffeine. We came across offspring developing inside the female daphnia which we found really fascinating. The fact that their bodies are opaque make them a great lab organism. During this experiment we had to repeat the steps 10 times for each substances which became really repetitive and frustrating. Another difficulty we faced was when we were counting the heart rate, as it was too hard to watch and record through the microscope at the same time and this caused anomalies. Overall the experience taught us a lot and helped us gain more experience for the future.