Caffeine In Blackworms

Introduction:

With over nine hundred and seventy one tons, the United States is the country with the highest amount of caffeine consumption in the world. This chemical compound is known to have many affects on our bodies, primarily in our hearts. Caffeine has been shown to increase blood pressure and heart rate. However, as far as scientists know, the affects of caffeine may affect invertebrates differently than it affects vertebrates. The present experiment studied blackworms - Lumbriculus variegatus in the phylum Annelida- in solutions with different amounts of caffeine to see if it affected their pulse under a compound microscope. Worms do not have hearts; they have aortic arches that contract to push the blood into the dorsal and ventral

I predicted that the blackworms in higher caffeinated solutions would have higher pulse rates, because caffeine is known to increase blood pressure and heart rate. However as far as scientists know, invertebrates are not expected to have a strong response to caffeine like vertebrates do. Also, caffeine in low doses is known to lower pulse rate. The results do not support my hypothesis. The results show that when black worms are placed in caffeinated solutions, their pulse rates on average are lower than those placed in a solution with no caffeine. A possible flaw that may have occurred during experimentation is that the petri dishes were not properly cleansed, or that there were other properties in the water that influenced the outcome. To eliminate these flaws, I could have boiled the petri dishes and water to insure that there were no other properties to influence the data. Further experimentation should be performed with higher doses of caffeine to further insure that caffeine does in fact lower their pulse rate. The insufficient number of trials performed lead to less confidence in my conclusion that caffeine lowers the heart rate in