Planarian Behavior

Topics: Hydrochloric acid, Planarian, Flatworm Pages: 7 (2630 words) Published: October 4, 2012
Planaria belong to the class Turbella of the phylum Platyhelminthes. This paper depicts the behavioral reaction of Planarians to a variety of settings and compounds to better understand this particular Platyhelminthes. With a plastic syringe, it is possible to extract a sample of planaria, place into a Petri dish with enough freshwater and observe under a laboratory provided microscope. While on the microscope platform, expose your sample to light and darkness to notice the patterns of locomotion and movement throughout the conditioning tray. Probe the individuals with an object to spot any type of distinct change in response, negative or positive. Tap the side and surroundings of the dish to notice if there is any different adjustment in movement. Add sound to surrounding, noting any alter. Obtain a second sample, labeled separately, and use one dish to apply Hydrochloric Acid and the other to salt (NaCl) water. Note: Only using minimal amount or as needed. Using the tools provided, cut an individual in half to discover if the subject dies or survives. In conclusion, the Planarian makes it choice by moving towards the darkened areas, favorably. When applied to light, the individuals fled towards the edge. Any sudden object, sound, or altering didn’t affect the objects intentions. After five drops of 6 mol HCl (aq), the sample died of very quickly; however, five drops of 6 mol NaCl (aq) did not kill off near as quick. It was applied directly to the conditioning trays. Introduction

Members of the phylum Platyhelminthes have a worm-like shape. The Platyhelminth has a bilateral symmetry and meets any provided situation in an “aggressive, head-on approach. Cephalization, a specialism of the anterior end of the animal, can be depicted in the gathering of sensory arrangement and cluster of nerves, also known as the ganglia or its brain, in the head region. Many of the behaviors you will see are associated to increases in mobility, higher activity, and general increase in responsiveness” (Collins, Harker 1999). Most planarians are free-living and common in freshwater environments, also found in marine and terrestrial places. Two ventral nerve cords run the length of the body. Located in the anterior end are two eyespots which possess photoreceptors to detect any form of light. Normally, a planarian contains a gastrovascular cavity that provides space for digestion tracts and the circulation of nutrient throughout the body. The mouth is located on the ventral end, which is the site for both food digestion and/or the release of bodily wastes. “Planarians are able to regenerate from essentially any type of injury and present a novel system for the study of wound responses in regeneration initiation. Planarian regeneration requires adult stem cells called neoblasts and amputation triggers two peaks in neoblast mitoses early in regeneration” (Wenemoser, Reddien 2010). Planarians are highly recognizable due to their ability to regenerate from the smallest body part. Typically vary in color from grey, brown or black. They seemingly move about on the bottom of rocks or submerged vegetation. Many are negatively phototactic, which simply means they shy away from any form of light fixture. Each worm has both male and female reproducing organs; however, they are monoecious in that they are not self-fertilizing. The most common form is asexual. They appear for function mainly as osmoregulation, the control of the levels of water and mineral salts in the blood. Planarians must constantly eliminate excess water and are carnivores that feed primarily on protozoans and other small animals. What is a Planarians reaction to a light fixture or exposed directly? Does it affect them in any way? What is the difference in responses from light and darkness? By inserting objects to the planarians path, does it alter their behavior? What about exposing them to sound or movement? Does making the water more acidic or basic affect the health and/or...
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