Biology - Planaria Research

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  • Topic: Flatworm, Nervous system, Annelid
  • Pages : 3 (955 words )
  • Download(s) : 814
  • Published : February 26, 2012
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Purpose: The purpose of doing this lab was to observe the regenerative patterns of planaria cells after a portion of their bodies was cut off. Background:
1.A blastema is a group of cells that forms at the site of a wound that eventually turns into the missing parts of a planaria. 2.Planaria fission occurs when a planaria is missing body parts. The organism attaches its tail-end to the ground and pulls itself forward using its head-end in order to tear itself into two parts. Then, each of these parts grows back the missing half, producing two new identical planaria. 3.A free-living flatworm ingests its food by opening its mouth, a cavity which allows food and water to pass. The food passes into the pharynx, a muscular tube near the mouth. The pharynx then pumps the food into the digestive cavity, called the gut. The cells in the gut digest the food, where nutrient absorption takes place. 4.Free-living worms eat tiny aquatic animals, as carnivores, or recently dead animals, as scavengers. 5.The digested compounds get to the other body tissues by diffusing out of the gut. 6.Planaria do not have a circulatory system. This is because since they are so thin and flat, they are able to use diffusion to transport materials throughout their bodies. 7.Flame cells are special cells found in flatworms that remove excess water and metabolic wastes from the cells through the pores of an animal’s skin. 8.Flame cells are only necessary in aquatic worms because since aquatic worms live in water, their cells are constantly absorbing water. Flame cells help the worms maintain homeostasis by keeping the amount of water inside the cells balanced. 9.DIAGRAM.

10.The ganglia are a group of nerve cells found in free-living flatworms that controls the nervous system. The ganglia are enclosed in the head of a flatworm. 11.The flatworm can detect external stimuli such as chemicals found in food and which direction water is flowing. 12.The function of the eye spot is so that...
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