Daphnia and Additives Lab
The purpose of this lab is to test what effect of Nicotine, Acetylcholine, Epinephrine, Caffeine, and Ethanol on an organism’s heart rate. Materials
* Eye dropper
* Cotton balls
* Depression slide
* Five additives: Nicotine, Acetylcholine, Epinephrine, Caffeine, Ethanol Procedure
1. Put on safety goggles.
2. Catch a living Daphnia.
3. Transfer to a depression slide and add water.
4. Add cotton ball fibers to restrict movement of the Daphnia. 5. Establish the resting heart rate of the Daphnia. Count the amount of beats for ten seconds then multiply that number by six to convert it to beats/min. 6. Add five drops of additive.
7. Wait for two minutes to the additive can absorb into the Daphnia. 8. Establish the new heart rate of the Daphnia. Count the amount of beats for ten seconds then multiply that number by six to convert it to beats/min. 9. Repeat steps 2-8 for each additive.
10. After each test remove the Daphnia into a provided beaker and throw away the cotton fibers. 11. At the end of the experiment clean up your work station. Variables
* Controlled: the amount of additive used, the type of organism each test was performed on * Manipulated: the type of additive
* Responding: the heart rate after an additive was added
Throughout the lab I noticed the behavioural change of the Daphnia as their environments were changed. Depending on the additive some began to move around in circles more than before and some less. Because the Daphnia are transparent I was able to observe their organs with and without the additive. (A labeled picture can be found below.) (Green: my experimental results Purple: class average)
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