Flatworm Lab Report

In this experiment, we analyzed the regeneration of planaria over a two week period. We chose to use flatworms due to their ability to grow into a new animal if cut in half or several pieces. This reproductive ability to regenerate is called fission and occurs in flatworms due to their embryonic stem cells called neoblasts. We obtained the flatworms used in this experiment by first placing a few drops of spring water on a petri dish so that the flatworms will be able to survive a couple of weeks, and not be dehydrated. Next, we used a pipette to gather the flatworm and then placed the worm on the petri dish, with the spring water. Using a razor blade, the worm was cut in half into two sections of 6mm in length and 5 mm in length. The worms were measured using a ruler, and examined under a microscope. I tried to measure the worms under the microscope, next to the ruler, to obtain the best measurement but as the worms moved sporadically and were not always fully extended this proved tough to do. So instead it was necessary to just eye ball the measurement of the worms, next to the ruler, when the worms were at maximum extension. Initially, I believed that the worms would regrow at the same rate as the neoblast are spread throughout the planaria, causing
The head segment of my flatworm, which was initially 6mm, grew to 7 mm after one week and then 8 mm after two weeks. The tail segment of the cut flatworm, which was initially 5mm, grew to 6 mm after one week and stayed at 6 mm after two weeks. These results demonstrate that the head piece was able to form a tail easier than the tail piece was able to form a head. These results may vary from my original predications due to the fact that I didn’t not cut the worm exactly in half, and that measuring the exact length of the worm proved to be difficult as the worms movements were