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Andrew Hamilton Honors Bio 5/6o Mrs. Hicks September 17, 2015 I. Abstract The Effect of Drugs on a Daphnia’s Heart Rate This experiment attempts to perceive the effects of certain chemicals, caffeine in cola, and alcohol. The daphnia was dropped into each of these solutions while we observed them for 15 seconds at a time. The heart rate was the dependent and main variable in the experiment. We record the number of heart beats in 15 seconds and then multiply it by for to get the BPS. With 5 trials for each liquid we would average them to get an accurate average. We discovered that alcohol acted as a depressant and that caffeine acted as a stimulant. Further verifying these results we hypothesized that this would be …show more content…
II. Introduction The Daphnia also known as a “water flea” is a microscopic organism that has a translucent body(1). The Daphnia is a subcategory in “zooplankton”, which is a group of mainly secondary consumers. This specific species of zooplankton usually gets no larger than 5mm in size. Because of the Daphnia’s semi­opaque “body” the heart can be observed directly making it very good for scientific experimentation. Just like any other organism, the daphnia must regulate its heart rate, also known as homeostasis(1). Drugs like ethanol and caffeine would have different effects on the daphnia’s heart rate. My hypothesis is that ethanol (alcohol) will slow the heart rate of the daphnia, just as it does in humans(3). I also hypothesize that caffeine will result in a greatly increased heart rate, and an increase in reflexes. III. Material and Methods In order to make our trials and tests permissible we first needed a “base” to determine the change the daphnia’s heart rate. The first step which we did involved counting the daphnia’s heart rate through a microscope. The daphnia was in spring water so we could find the “base” or the average heart …show more content…
Due to my assumptions the results were not surprising. However what was surprising was the drastic change between the heart rate while on caffeine and that of the one on alcohol. Assuming that there is a common ratio between the amount of caffeine or alcohol and the size of the daphnia then the more caffeine taken in by the daphnia the higher or lower the heart rate will go. If the daphnia is large then the amount of “substance” that it needs to increase or decrease will increase in dosage, while if it is small the dose will too become smaller. Given the fact that the two daphnia’s that were used were not .measured by length or weight our results could have been skewed and may not be exactly the same if we were to attempt it again. The daphnia categorized as a zooplancton(2) is also part of the subphylum Crustacea(4), this may result in similar characteristics to other crustaceans. Because of this many other crustaceans may react the same way as the daphnia did in this circumstance. Because humans also must maintain homeostasis if given the correct dosage of alcohol or caffeine they would most likely experience the same time. Performing this experiment could result finding a way that humans and most