Daphnia Research Paper

Introduction Daphnia or "water fleas," are small aquatic crustaceans. They live in a variety of aquatic habitats, including freshwater lakes, streams, ponds, and rivers. These organisms are useful for biological research due to their important interactions within their ecological niche. An ecological niche is the role and position that a species occupies within its ecosystem.

Daphnia has a myogenic heart which differs in structure from human hearts but shares similarities in the way it is controlled. The heart rate is controlled by neurotransmitters which send signals to the heart, telling it the rate and rhythm. Ethanol is a clear, colourless liquid that can alter heart rate by affecting neurotransmitter activity. Ethanol is known to control …show more content…
The trend was discovered aligned with well-established biological principles of cardiovascular physiology. This biology was evident in the data, where the highest ethanol concentration (50%) corresponded to the lowest average heartbeat per minute (42.8 BPM), while the lowest ethanol concentration (5%) corresponded to the highest average heartbeat per minute (283.5 BPM). The average heart rate of the control group (0% ethanol) was 330.6 BPM, which was used as a benchmark for comparison. The average heart rate at 5% ethanol was 283.5 BPM, which was a significant drop. The average heart rates decreased to 228.8 BPM, 130.6 BPM, 79.6 BPM, and 42.8 BPM at 10%, 20%, 30%, and 50% ethanol concentrations, respectively, as this pattern persisted as the ethanol concentration increased.

Heart rates in many animals are controlled by the parasympathetic nervous system. Functionally this is achieved through a neurotransmitter called acetylcholine activating receptors on the surface of cells in the sinoatrial node. A decreased heart rate is beneficial for animals during times of rest, as it allows for the conservation of energy. Past experiments have used acetylcholine to decrease the heart rate of people with diabetes. Similarly, in the present experiment, ethanol was used to decrease the BPMs of daphnia. Ethanol acts as a non-selective neurodepressant by suppressing the nervous …show more content…
This offers important new information about how different ethanol concentrations specifically affect Daphnia physiological responses. In the present investigation, for every 1% that the ethanol concentration increased, the heartrate decreased by 0.89 BPM. 0.89 is the R2 value, which is the proportion of the variation in the dependent variable that is predictable from the independent variable. Criscillo and Moffat 2024, has an R2 value of 0.88. This means in their experiment, for every 1% that ethanol increased, the heartrate decreased by 0.88 BPM. Since the R2 values are very similar, this shows that we both have an exponential link and therefore the biological concepts behind this trend are the same. How sources of error were eliminated In the method we included repeating each concentration five times. Conducting the experiment five times not only enabled us to identify potential errors that might have been overlooked in a single trial, but also gave us a heightened level of precision in measuring the average BPM. The ability to calculate averages reduces the impact of random fluctuations, leading to increased accuracy. This helped irregularities that were seen in several trials to be smoothed down, making the average BPM representation more accurate and dependable. Another way I ensured my method was valid and eliminated sources of error was by adding

Show More