The Reaction of Dugesia in Predator Water

Bio 218 |

The Reaction of Dugesia in Predator Water |

Experiment Paper |

Tuesday 6:00PM Lab |

Josh Macha |

4/2/2013 |

Introduction:

Predation occurs at all levels of living organisms, starting with the smallest of organisms and ending with the biggest of organisms. Interactions amongst predator and prey are happening all around us at all times. Some organisms have developed mechanisms to warn other organisms of the risk of predation. Planarians are the most primitive living animals with an organized central nervous system (Wisenden and Millard, 2001). Dugesia make up a large percentage of the biomass in freshwater, marine environments (Winkelmann et al, 2011). The planarian Dugesia will be used in the study to determine if Dugesia use chemical cues to evade predation. Dugesia are a genus of Platyhelminthes that are native to freshwater habitats in Africa, Europe, Middle East, Asia, and Australia (Beier et al, 2003). The study will track the movements of Dugesia in the presence of predator water.

Methods:

This experiment was conducted by placing predator water into petri dishes containing Dugesia. Each petri dish was divided into two sections. One section was labeled “danger” and the other section was labeled “safe.” The “danger” section was the section that the predator water was introduced to. The “safe” section was the section that no predator water was added to. The predator water was created by crushing several Dugesia in a sample of water, simulating a Dugesia being preyed upon. Four Dugesia were placed into each petri dish. Two were placed into the “safe” section of the petri dish and two were placed into the “danger” section of the petri dish. Three drops of the predator water was then introduced to the “danger” section of the petri dish. The movement of the Dugesia was then recorded for ten minutes. At each two minute interval the number of Dugesia in each section was recorded. Three trials were conducted with predator water and three...