In this experiment, we questioned whether one section of a planarian’s body (anterior, middle, or posterior) would be more responsive than the others. We hypothesized that there would be a greater response to touch from the anterior section than from the middle or posterior sections. The null hypothesis would be that there is no section of the planarian has a greater response to touch than the others. We tested this hypothesis by gently pressing on each section of two different planarians with a toothpick. We touched each section ten times each, and recorded the number of times the planarians responded in each section. Both planarians responded all ten times to touch on their anterior sections, one time on their middle section, and an average of six times in their posterior sections. So the anterior section seems to be more responsive to touch than the posterior or middle section of the body. Introduction
In this experiment, we wanted to find out if one section of a planarians body is more responsive to touch than the other sections of the body. In the Introduction to Zoology: A Lab Manual, we found that the “Brain” of a planarian and an abundance or “aggregation” of sensory nerve cells are located in the anterior end of its body, making it likely that the anterior would be more responsive to touch than the middle or posterior ends as we hypothesized (Hopkins & Smith, 1997). Materials and methods
The subjects of this experiment were two planarians. They were placed in a single Syracuse dish with a small amount of spring water. Once the planarians settled down we commenced to lightly prodding each planarian. We touched each section of both planarians ten times. Each response to touch from the planarian was recorded. The independent or manipulated variable during this experiment was which section of the body the toothpick touched, the controlled variable was the number of times each section was poked, and the dependent or measured variable was the...
Please join StudyMode to read the full document