Daphnia Lab Report The effect of the Amount of Caffeine on the Average Heart Rate of a Daphnia magna

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Period 2 Date of Experiment: 10 May 2018 Due Date of Lab Report: 25 May 2018 The effect of the Amount of Caffeine on the Average Heart Rate of a Daphnia magna Purpose: The purpose of this experim... ent was to find out how the amount of caffeine affects the ​Daphnia​’s heart rate. Background Research: A ​Daphnia magna ​is an animal closely related to a shrimp with a clear outside skeleton, where you can see its heart which is on its back, and jointed legs. Caffeine is a stimulant that speeds up the heart rate of the organism that consumes it, which is the opposite a depressant, that slows down the heart rate. Caffeine expels sleepiness because it acts as a stimulant to the central nervous system. Adenosine causes a person to feel drowsy which is blocked by caffeine. Caffeine also triggers specific portions of the autonomic nervous system which improves mental awareness and reflexes. Caffeine also has many other uses like: helping with asthma, attention deficit-hyperactivity disorder (ADHD), low blood pressure weight loss, and type 2 diabetes. Hypothesis: If the ​Daphnia​ is subjected to 0.001 percent of diluted caffeine— compared to the 0.000001 percent, the 0.00001 percent, and the 0.0001 percent— then it’s heart will beat at the fastest pace because the 0.001 percent caffeine solution will be more concentrated than the rest. I base my hypothesis on the idea that because caffeine is a stimulant, which is something that raises levels of psychological and nervous activity in the body, that the effect will be the same in the ​Daphnia as it is on humans- increasing the heart rate. Variables: ● Manipulated Variable: percentage of caffeine in the water ● Responding Variable: ​Daphnia​’s average heart rate per minute ● Constant variable: Same ​Daphnia​ throughout experiment, light intensity from microscope, compound microscope (set on 4X), type of container the caffeine solutions are in, wells slide with coverslip, time (10 seconds) for each trial, type of transfer pipettes Materials: ● 4 pipettes ● 1 microscope [Show More]

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