Variables: Independent -nicotine added to pure water Dependent -worm pulsation rate (pulse/minute)

1. Procedure: Label each container as follows: Control, Control R, low, medium, high, Water 1, Water 2, and Water 3. Fill the dishes labeled Control, Control R, Water 1, Water 2, and Water 3 with approximately 50 ml distilled water. Fill the three remaining dishes with each of the nicotine solutions. Place ten worms in each of the nicotine solutions and ten worms in the pure water. Let worms sit in pure water and solutions for 15 minutes. Using a pipette, place a worm from the dish of Solution low on a slide with a well, with a minimum amount of water. On 10x, focus on a single vessel in the mid-section of the worm, and count the worm’s pulse for 30 seconds, and multiply by two to calculate pulsation rate for one minute. Remove worm from slide, using pipette, and place in the recovery dish for worms after use. Repeat with nine worms from Solution low, repeat with all ten worms from each nicotine solution and pure water. Record and analyze data. Note any observations of worm’s behavior. The Effect of Nicotine on LumbriculusvariegatusBy: Samantha Gramlich and Alison O’Hearn, AP Biology Albion High School • Results: The mean pulse rate of the high solution worms increased; the mean for the low and medium solution worms showed a decrease in pulse rate. Conclusion: The data collected supports our hypothesis, but only for the high concentration. The pulse rate in the blackworm increased for this solution by 5.2 pulses per minute. In the low and medium solutions, the pulse rate decreased by 3.8 and 4.2 pulses per minute, respectively. Nicotine is traditionally a stimulant; we believe that these results occurred because the concentration of nicotine wasn’t high enough to directly increase the worms’ pulse rates. Our results may have been adversely affected because as we were only able to measure the pulse rate of one worm at a time, some worms remained in the solution longer than the instructed time. The last worm observed stayed in the solution much longer than the first worm. Waiting for the worm’s pulse rate to regulate before measurement on the slide, due to the stress associated with transportation, could have improved our results. The next step in testing would be to more closely observe the worms’ behavior in and out of the different concentrations. Introduction: Nicotine is a highly addictive drug, commonly found in cigarettes and chewing tobacco. In a low dosage it is considered a stimulant, but in high dosage it can be fatal. The receptor for Acetylcholine, a chemical in charge of communication between brain cells, opens a pore in the cell’s membrane which allows the nicotine to flow into and out of the cell. We are using Lumbriculusvariegatus, the California blackworm,to test the effect of nicotine. The blackwormis ideal for testing the toxin because it is transparent and has a closed circulatory system. We are testing our worms in high, medium, and low solutions of the nicotine. We are keeping the blackworms in each solution for 10 minutes before testing their pulse rates. Physical changes such as the worms twitching and curling their tails in the nicotine solution or paralysis occurring, causing them to float will also be noted for the varying concentrations. Hypothesis: If the worm is placed in a solution of nicotine, then the worm’s pulse rate will be increased. Materials: 40 California blackworms, pipette, calculator, pure water, microscope, stopwatch, 4 uncontaminated dishes, cover slip, viewing slide (with well), permanent marker, solutions of nicotine (high, medium, low), distilled water, 500 ml beakers (4) Variables: Independent-nicotine added to pure water Dependent-worm pulsation rate (pulse/minute) Constants- water temperature, pulse counter, nutrients fed, type of cigarette and type of worm Control Group- pure water worms Reference: www.eeob.iastate.edu/faculty/Drewesc.htdoc, www.niehs.nih.gov/health/assets, http://www.ableweb.org/volumes/vol-27/07_Bohrer.pdf