п»їEvrhett Davis, Andrew Staub

Saint Joseph's University

Organismal Lab Wednesday

Dr . Jonathon Fingerut

12 , 1, 2013

Thigmotaxic Variant Between Cephalic and Fortuna Regions in Planaria

The introduction of a central nervous system in primitive animals presented a significant benefits resulting in the continuance of countless species. Stressed tissue allowed organisms to expand into new techniques of predation, security and reproduction; encouraging specialty area and eventually increased speciation. Yet , there may well exist elements which could have contributed to the perseverance of nervous tissues. Does the occurrence of old fashioned nervous tissue affect an organism's respond to localized mechanised stimulation? To understand this question better, a primitive affected person is best suited. Planaria were chosen as the most appropriate model patient for their ease of maintenance, attainability and their existence of a light sensing organ, or primitive cephalization. " Planarians are the initial example of creatures displaying cephalization, including a primitive brain, numerous features popular among a vertebrate nervous system" 1 . This relationship offers a strong relevance to vertebrate animals.

Twenty Planaria specimen were analyzed. Each had been isolated after which mechanically stimulated in a 'poking' manner by way of a blunt dissecting probe. To examine the difference in thigmotaxis among areas of numerous cephalization, hereby referred to as the organism's 'head', and the rest of the organism's body, stimulation was localized to 3 regions: the top, the tail and the body system (the physique consisting of the estimated advanced area involving the head and the tail). The resulting reactions were in that case recorded and categorized by subjective intensity of the response on a level of 1 to five, with you being an agreed neutral response and 5 being an uncharacteristically extreme response. Furthermore, reactions were also noted qualitatively in an attempt to find a...