Science Grade 8

Activity A gutsy game1A Activity 1 is a board game that is played with tokens and a die (refer to theboard game on the next page. This game aims to help students identify the organsthat make up the digestive system and describe the function of each organ.Moreover, the game should also be able to help students describe the interactiontaking place in the digestive system as these organs carry out the digestion of food. Guide the students through the procedure. The game may be played in pairsor in groups of 5, at the most. There should be as many tokens as there aremembers of the group. The first member to make it all the way through the digestivesystem wins the game. As the students play the game, guide them through thequestions that follow. After they have finished the game discuss with the class theiranswers to the questions.Teaching Tips Figure 1. The human digestive system.13. The game is an analogy of some processes involved in the digestive system and not a simulation. As such, it has its limitations. The game aims to help students to identify the organs that make up the digestive system and to describe the function of each organ.14. Discuss with the students what they understood about the concept of digestion and the processes involved in the digestive system after playing the game. After which, ask them what other things they would like to learn about the digestive system. 206

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15. During the game, it helps if you post on the board an illustration of the digestive system or display a model of the human torso -- if available. If not, the students can refer to Figure 1. The playing pieces or tokens used in the game represent the food we eat. Thespaces on the game board are a representation of the different parts of the digestivesystem through which food passes. Have the students describe the illustrations inthe board game and how these illustrations relate to the digestive system and theprocess of digestion. Notice that there are spaces or boxes on the game board thatasks the players to move back several spaces. Ask the students if they can think ofan instance when the food that was just eaten moved back.Answers to QuestionsQ1. The tokens represent the food that was eaten.Q2. The spaces on the board game represent the different organs or structures of the digestive system.Q3. The directions on some of the spaces describe the different physical and chemical conditions that affect proper functioning of the digestive system.Q4. The digestive systems of different representative species of animals are similar to each other in that they are all made up of a continuous tube with two openings: the mouth and the anus. But as shown in Figure 2, certain differences are also noted particularly on the structures that compartmentalizes the different digestive tracts.Digestion in Animals Digestion in animals is carried out physically and chemically. Physicaldigestion refers to the physical breaking down of food to smaller pieces; chemicaldigestion changes the large molecules in food into their building blocks. In the lowergrades, the students have learned how these processes are carried out in the humandigestive system. At this point, call the students’ attention to Figure 2. Have them compare thedifferent structures of the digestive systems of different representative organisms.How are they alike and how are they different? What structures do some specieshave in their digestive system that other species do not have? What purpose dothese structures have in the digestive system of these species? At the end of the activity, have them visit the library or certain trustedwebsites to read more about the parts or structures that are unique to each of theseorganisms. Ask the students how these structures and their functions are the sameor different from those of humans. 208

Figure 2. Digestive systems of different representative species of animals. The process of digestion is not unique to humans. Even the simplest animals-- the invertebrates -- have structures they use to digest food. Refer the students toFigure 3 and have them describe the process of digestion in Hydra. The studentsshould be able to note that the Hydra has a ‘digestive system’ that has only oneopening -- the mouth! This is called an Incomplete Digestive System. Have the students read more about digestion among invertebrates and havethem name other organisms that have incomplete digestive systems. In yourdiscussion have them compare the digestive system of invertebrates with those ofthe vertebrates. 209