WCCC/ Spring Semester 2015
A&P II/
Matt S.
The Effects of Varied Substances on a Daphnia’s Heart Rate.
Introduction:
The purpose of this experiment was to compare the resting heart rate of a Daphnia, to its heart rate after 5 different substances were tested on it: Aspirin, Nasal Spray, Alka Seltzer, Coffee and Tea. Daphnia’s are often used as an experimental animal in lab settings because they are small, have a short life span and are easily maintained, only needing water to survive. For this specific lab, it was important that we have a test subject whose heart is visible under a microscope. The Daphnia was perfect because these water fleas are very small, and their bodies are enclosed by a transparent …show more content…
Obtain a Microscope and plug it in.
2. Collect a pipette and “suck up” a Daphnia with it.
3. Release the Daphnia onto the depression slide with the least amount of water possible.
4. Use a Kim Wipe to soak up excess water; enough so that the Daphnia can no longer swim.
5. Place the depression slide under the microscope and find the Daphnia’s heart.
6. Count its heart beat for 15 seconds and multiply the number by 4 for get its resting heartbeat. Record data.
7. Obtain the liquid Aspirin and place 1 drop on top of the …show more content…
Place the slide back under the microscope.
9. Find the heart and count its heartbeat for 15 seconds and then multiply by 4 to get the results. Record data.
10. Take the Daphnia and place it in a bin of water.
11. Obtain and new Daphnia and repeat with Alka-Seltzer, Nasal Spray, Coffee and Tea.
Results:
Table 1: The Change in Heart Rate; Before and After Drugs.
SUBSTANCE HEART RATE BEFORE HEART RATE AFTER CHANGE % CHANGE
Aspirin 200 176 -24 12% decrease
Nasal Spray 176 160 -16 9.1% decrease
Alka-Seltzer 168 169 +1 .6% increase
Coffee 196 224 +56 28.6% increase
Tea 168 180 +12 7.14% increase
Discussion: Investigating the effects that the five different drugs had on a Daphnia’s heartbeat was very interesting to do. The first expectation that Aspirin would slow down the Daphnia’s heart beat was proven correct. The heartrate had a 12% decrease, and this is believed to have happened due to the active ingredient in Aspirin, acetyl salicylic acid. The second drug that was tested on a new Daphnia was Nasal Spray. The hypothesis that the heart rate would stay the same was rejected. It was found that nasal spray actually decreased the heartrate by 9.1%.
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