Flatworm Lab

Flatworm Lab: Platyhelminthes

Experimental Design: Planaria are free-swimming mostly freshwater flatworms. Flatworms are very unique creatures because they regenerate lost parts. My groups experiment was, The Effect of Darker Regions on Planaria Movement. The purpose of this experiment was to see whether or not the planaria preferred the white region or the dark region. My hypothesis was, If the Planaria are placed on the white side then they will move to the dark side because the planaria have a strong negative geo-tropism and would move away from white side and go to the dark side. The independent variable was the two sides of the petri dish, which had one white region and one dark region. The dependent variable consisted of how many
The petri dishes when combined formed a make-shift reservoir for the planaria. We then filled both petri dishes with 25 ml of water and covered the outsides of each petri dish with a white paper and a black paper. We then placed the planaria on the white side and waited 5 minutes. When the 5 minutes were up we counted how many planaria were on the white side and the dark side, then we put the data found in a table. We then repeated this process two more times to get more accurate readings. Our constants in this experiment were, 5 minutes per trial, planaria were placed in the middle of the white section, petri dishes, colored paper, elevation of petri dishes, room temperature, and same type and amount of water. To see if our hypothesis was valid
We created a small reservoir for this experiment to take place using petri dishes. We used brown paper as a dark side of a petri dish and a whit sheet for the light side. We placed the planarians in the middle of the white petri dish for our trials. in the end of the experiment we found out that more planarians went to the dark side instead of remaining in the white side. From the research I have done on platyhelminthes I concluded that the results came to be by natural selection, and how organisms camouflage themselves to hide from predators by blending in with there surroundings. This idea is supported in the observations I made because since the planarians were darkly colored they moved to a spot with more dark colors instead of being in a place with no color(the white side) and being very visible. My hypothesis, If the Planaria are placed on the white side then they will move to the dark side, was supported in this experiment. it was supported because the majority of planaria moved to the dark side instead of staying in the white side. Even though we made few errors in our project, our results should not be changed so much. If I could have changed the experiment in one way, I would have chosen to use a stopwatch instead of a analog clock to keep the time. I believe my partners in the grouped participated in the experiment equally. I also believe that each person did the same