The Effects of Stimulant on Lumbriculus variegatusBy: Rebecca Flanagan and Kendra Morrison

Introduction: Lumbriculus variegatus, or the California Back Worm, is a small, transparent worm These worms reside in shallow, wet areas. Lumbriculus variegatus have an open circulatory system which is visible from the outside of the worm. Due to the transparence of the worm we were able to view the worm’s pulse, and the effects of water with stimulant on the worm’s pulse. In most animals stimulant would raise the pulse.

Conclusion: After finding the pulse rate of five Blackworms in plain, distilled water and five Blackworms in water with a stimulant, the average pulse rate of the plain worms was 17.4 pulses per minute while the average pulse rate for the stimulated worms was 15.6 pulses per minute. We hypothesized that the stimulated worms would have a faster pulse rate than the plain worms, but they did not. One question raised by the results of this experiment is: Why didn’t the stimulant affect the worms? One problem with the procedure was the worm often moved out of the microscope’s line of sight.

References: www.eeob.iastate.edu/faculty/drewesc.htdoc

2) With a pipette collect one worm and place it into the well slide. (Dabbing the well slide with paper towel after placing the worm on the slide may make this process easier.)3) Place the well slide with the worm inside on to the stage of the microscope.4) Turn on the microscope, and collect the worm’s pulse rate by looking through the eye piece of the microscope.5)Remove the well slide and the worm from the microscope.6) With the pipette remove the worm from the well slide.7) Place the worm into a new one of the containers.8) Repeat this process until all of the data of the experiment is collected.

Materials:• Microscope• Pipette• Well Slide• 4 Plastic cups

Hypothesis: If the worm is in the stimulant water the it’s pulse will be higher than the pulse of the worm n the plain water.

Independent Variable: Water with stimulant

Dependent Variable: Pulse per minute

Controlled variables: Water temperature, type of worm, the person counting the pulse, the tools used, the power of the light used to view the worm on the microscope.

Procedure:1) Get a cup of five plain water worms, another cup of five water with stimulant worms, and two clean cups.

Data:

Plain Worm Stimulant Worm 14 14 20 16Pulses Per minute 18 15 20 16 15 17Average 17.4 15.6

Lumbriculus variegatus

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