The effect of stimulants on the heart rate of Lumbriculus Variegatus By: Logan London and Nita Bela Introduction The Lumbriculus Variegatus, or commonly known as the blackworm, is made up of approximately 150 body segments. Blackworms are traditionally used for research because they are fresh water annelids. Their thin transparent skin allows easy observation of their circulatory system and how it works. They also react immediately to any drug that is tested on them. This helps many scientists discover reactions of different substances in living organisms. If we measure the pulse rate of worms in a stimulant water mix, then it will have a faster pulse rate than the worms in standard spring water. Materials: For our materials we used a well slide, pipettes, stimulant solution, petri dishes, spring water, blackworms, and a microscope. Conclusion: We concluded that our results match our hypothesis. The average pulse rate for the worms in the stimulant is 17.25 while the average pulse rate for spring water is 12.75. Stimulants are known for speeding up the pulse rate of many organisms. Although our results matched our hypothesis the first time, more trials would make our experiment more accurate and ensure that the stimulant rises the blackworms pulse rate per minute. Also instead of using a prepared stimulant, we would like to know exactly what our substance was so that we could do further research. Doing this experiment made us wonder as to what the effects of depressants would have on the pulse rate of the Blackworms. Methods: We started the experiment with a prepared stimulant. We had a bunch of worms in a bowl with the stimulant and a bunch in regular spring water. We used a well to look at the worms under the microscope. The well is a slide with three layers of heavy duty tape and a slit in the middle. This made it easier for us to see the worms under the microscope after placing a cover slide on top. We also used a pipettes to help transport the worms between the dishes and the slides. We looked at four different worms from the spring water and measured the beats per minute. Then we looked at four different worms from the stimulant substance and measured their beats per minute. When looking at the worms under the microscope we made sure that we didn’t leave them on there too long because the heat and the light from the microscope could effect the pulses of the worms. Then we calculated the mean and median of the two sets of data and created a bar graph showing the comparison of the pulse rates of the worms from the stimulant to those of the spring water. Results We calculated our data and found that when the worm had soaked in the stimulant the pulse rate averaged at 17.25 beats per minute and all four trials had a median of 18 beats per minute. When the worm had been soaked in standard spring water, we had found the pulse rate averaged at 12.75 beats per minute and the median of those four trials had a median of 12.5 beats per minute. Regeneration of head after week one http://biol-150-fall-2007.wikispaces.com/Lumbriculus+variegatus+Comparative+Regeneration+of+the+Head,+Tail+and+Mid-Section Independent variable: Stimulant Dependent variable: Pulse rate per minute of the worm Constants: Temperature, Light/Darkness, Containers Control: Worms in the spring water http://www.eeob.iastate.edu/faculty/DrewesC/htdocs/toolbox-V.htm Refrences: Drewes C.D. (9-2004). Lumbriculus Varoegatus: A Biology Profile. http://www.eeob.iastate.edu/faculty/DrewesC/htdocs/Lvgen4.htm