THE EFFECTS OF A TOXIN ON THE PULSE RATE OF THE LUMBRICULUS VARIEGATUS By: Katie Mann and Adryan Cheeseboro Albion High School Genesee Community College Bio 100 Introduction- We used Lumbriculus variegates, commonly known as the blackworm for our toxin experiment. The blackworm’s environment is the shallow edges of (usually) still water (ponds, lakes and marshes). The black worms are asexual and they use a process called autotomy to split themselves into different fragments. After splitting the worm will regenerate either a new head or tail end. The black worm is a good test subject for our experiment because they have a transparent skin. What allows us to see the fluid cavity and dorsal blood vessel is the hydrostatic skeleton of the worm. The blood of the worm circulates in a closed system of vessels and capillaries and is pumped in rythmatic contractions. The toxin used in this experiment is aspirin. Aspirin is taken as a pain killer for headaches, cramps and aches. It is also used to help un-clot the blood which allows the blood to flow more freely through the arteries. Materials - A microscope 2 cut slides 10 black worms Spring water 2 pipettes 10 petri dishes A recovery dish A rinsing dish Procedure- 1) Make a solution of aspirin water.2) Add ten worms to the aspirin solution for 4.5 minutes 3) Using a pipette remove one worm and put it in a well slide. 4)Take the worm’s pulse rate for thirty seconds and multiply the number by two to get pulse per minute.5) Take the worm out and put it in a recovery bowl. 6) Repeat with nine more worms. *Schedule times of when to introduce the worms to the solution. Hypothesis - If a black worm is placed into the solution of the aspirin than the pulse rate will increase compared to the worm’s pulse rate in normal spring water. Independent variable- Aspirin Solution Dependent variable- Worm’s pulse rate Control setup- Worm’s pulse rate in spring water Constants- The temperature of the water and how long each worm is sitting in the solution. Solution/Mix - The solution was made up of aspirin and spring water. The measurement of the aspirin had to be cut down so it wouldn’t harm the black worm. The aspirin was a 325mg pill that had to be crushed up; the weight of the crushed up pill was approximately.28. The first thing done to lower the strength of the toxin was cut the powder in half two times, it ended with the weight of.07. Since the pill was 325 mg and it needed 1 liter of water, the second cut would be 162.5mg so it would need 500 mL, then the last cut would be 131mg so it would need 250 mL. Results- The average pulse rate for the control group was 18.2 and the average pulse rate for the aspirin group was 25. There was a major increase in the pulse rate but association does not imply causation. 8 out of 10 with this data would imply that the pulse rate would increase. Conclusion -The average pulse rate of the worms in the aspirin solution was 12.5beats per minute. That is more than their average pulse rate in spring water which was 9.1. That is almost 4 beats more than the average in spring water. Our hypothesis was right, the pulse rate did increase in the aspirin solution in contrast to the spring water. When we do the experiment again, to be more accurate we could test even more worms. To further test the effects of an aspirin solution, we could increase or decrease the concentration of the aspirin solution. We could also test the difference between a generic and name brand for example Bayer in contrast to a Tops or Walmart brand. Timing- Each worm had its own set of petri dishes which one dish had normal spring water and the other dish had the solution. The water and solution just covered the bottom of the dishes so the worm could still behave normal. The first worm was placed in the first dish of normal spring water for 5 minutes, then 1 minute and 30 seconds was taking out to get the worm on a slide to test its normal pulse rate. Then the same worm was transported to the solution mix to sit in for 5 minutes. When it got to a minute left we added the next worm to the spring water so the timing could be constant but it would speed the process up. While the worm were in each dish we tested the behavior. This was then tested for the other worms. After the pulse rate was taking when they were in solution they were put into a recovery bowl.