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Effects of Chemicals on Blackworm Pulse Rates

Julianna, Elizabeth, Jill
by

Jill Humphreys

on 14 September 2012

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Transcript of Effects of Chemicals on Blackworm Pulse Rates

photo (cc) Malte Sörensen @ flickr Effects of Chemicals on Blackworm Pulse Rate: Julianna D., Elizabeth B., Jill H. Phenylephrine and Metab-O-Lite Introduction Question: How will the exposure to different chemical substances (Metab-O-Lite and phenylephrine) affect the pulse rate of blackworms? Background: Blackworms (Lumbriculus variegatus) are excellent organisms for studying the effect of drugs on the circulatory system: their transparent skin makes it easy to observe the pulse rate, drugs quickly diffuse through the skin of blackworms providing immediate effects, and blackworms are easy to maintain in a laboratory.

Metab-O-Lite is a diet pill and contains ephedra, a stimulant; it increases heart rate and metabolism. Phenylephrine is a decongestant drug that is used in place of the stimulant pseudoephedrine. It does not have the same stimulant qualities.

Blackworms have already been exposed to other chemicals known to be stimulants or depressants (caffeine and ethylene). These chemicals generally increased the worms’ pulse rates from the control group average. This experiment will test other chemicals to see the effects they have on blackworm pulse rate. Hypotheses: If the blackworms are exposed to the diet pill Metab-O-Lite, then their average pulse rate be greater than that of the control group. The diet pill is a stimulant meant to increase metabolism.
If the blackworms are exposed to phenylephrine, a drug used in place of pseudoephedrine, then their average pulse rate will not vary greatly from the average pulse rate of the control group. Pseudophedrine is a stimulant but pheylephrine doesn’t have the same stimulant effects of pseudoephedrine. Materials:
Blackworms (2)
Metab-O-Lite pill
Nasal Decongestant pill- phenylephrine
Mortar and pestle
Pure water
300 mL beakers (2)
Weighing boats (2)
Small pipettes (2)
Capillary tubes (2)
Microscope- 4X Methodology Results
High school students investigate the effects of stimulants and depressants on multiple blackworms’ heart rates (bpm). The blackworms’ heart rates can be easily seen due to the transparent skin that covers the worm and blackworms can easily absorb the chemicals/liquids that they are immersed in. These two factors allow the students to be able to easily make the worms absorb the depressants/stimulants being tested and to observe the effect that the chemicals make on the worms’ heart rates (bpm). Abstract Each group of students first tested the effect of distilled water on the blackworms’ heart rate as the control group. Then each group proceeded to test the effect of caffeine or ethyl alcohol on the blackworms’ heart rate. After testing the effect of caffeine and alcohol each group had to choose one or two other chemicals that they thought would affect the heart rate in the blackworms. Our chosen chemicals were phenylephrine and metabolite (diet pills). As shown by the data, the heart rate of the blackworms submerged in the distilled water (control) averaged about a heart rate of 6.8 bpm, ranging from 6 to 8 bpm. This is 4.12 bpm lower than the class average of 10.92 bpm. The data for the effect of ethyl alcohol on heart rate fluctuated from 27 bpm to 45 bpm and averaged 35.6 bpm. Which is 28.8 bpm higher than our recorded average of the regular blackworm heart rate and 24.68 bpm higher than the class average of the regular heart rate. The recorded heart rate for the effect of Phenylphrine averaged 7.6 bpm, reaching as high as 9 bpm and as low as 6 bpm. This is .8 bpm higher than our recorded average blackworm heart rate and is 3.32 bpm lower than the class average. The data for the effect of Metabolite (diet pills) on blackworm heart rate averaged 9.6 bpm. The highest heart rate recorded for this stimulant was 12 bpm. The rest of the recorded heart rates were consistently 9 bpm. The recorded average is 2.8 bpm higher than the average heart rate of the worm we used as the control and is 1.32 bpm lower than the class average of the control of the blackworm heart rate. Box and Whisker Plot Discussion Our first hypothesis, If the blackworms are exposed to the diet pill metabolite, then their average pulse rate will be greater than that of the control group, is supported by our results. The average pulse was 9.6 bpm compared to our control of 6.8 bpm. Because our average control group pulse was so much less than the class average of 10.92 bpm, it is more accurate to refer to our own control group, since it may be possible that the methods of finding the pulse on the blackworms were different from those of the rest of the class. With the average pulse rate of the Metabolite found to be significantly greater (2.8 bpm) than our control group, we can conclude that our results support our hypothesis, and that Metabolite does have a stimulating effect.

Our second hypothesis, If the blackworms are exposed to phenylephrine, a drug used in place of pseudoephedrine, then their average pulse rate will not vary greatly from the average pulse rate of the control group, is supported by the data. The average pulse rate for the worms exposed to phenylephrine is 7.6 bpm, while the control group's was 6.8 bpm. The difference is only 0.8 bpm which is not a great difference. Therefore, the phenylephrine does not have a very stimulating effect, compared to the results of the control group.
This laboratory experiment was a perfect example of how scientists can use labs to prove or confirm theories, or expected effects of certain conditions on a studied subject. In this case, the subjects were the blackworms, and they were studied under the different conditions of exposure to chemical environments. First, a control group was used to provide a basis for the comparison of the results of the different conditions, and the effects of the different chemicals were observed in the same manner as the control. In this way, the experiment is controlled and the results are more reliable, because the normal state of the subjects' is observed and compared to their induced states. With this experimental structure, it was possible to confirm that the hypothesis were correct, and that both drugs work the way they're supposed to, with predictable stimulating or depressing effects.
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