Assignment II.2 Food Chain Gizmo

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Name: Breyanna Date: Student Exploration: Food Chain Vocabulary: consumer, ecosystem, energy pyramid, equilibrium, food chain, population, predator, prey, producer 3 points for each re... sponse in a question. Prior Knowledge Questions (Do these BEFORE using the Gizmo.) The Food Chain Gizmo shows a food chain with hawks, snakes, rabbits, and grass. In this simulation, the hawks eat snakes, the snakes eat rabbits, and the rabbits eat grass. 1. Producers are organisms that do not need to eat other organisms to obtain energy. A. Which organism is a producer in this food chain? B. Where does the producer get its energy? 2. Consumers must eat other organisms for energy. Which organisms are consumers in this food chain? . Gizmo Warm-up The SIMULATION pane of the Gizmo shows the current population, or number, of each organism in the food chain. 1. What are the current populations of each organism? Hawks: _ Snakes: Rabbits: _ Grass: _ 2. Select the BAR CHART tab, and click Play ( ). What do you notice about each population as time goes by? If populations don’t change very much over time, the ecosystem is in equilibrium. 3. Notice the populations decrease as you go from the bottom of the food chain to the top. Why do you think this is so? This diagram, showing decreasing populations at each level, is called an energy pyramid. Activity A: Predator-prey relationships Get the Gizmo ready: • Click Reset ( ). • Check that the BAR CHART tab is selected. Question: Predators are animals that hunt other animals, called prey. How do predator and prey populations affect one another? 1. Observe: Run the Gizmo with several different starting conditions. You can use the + or – buttons to add or remove organisms, or you can choose Diseased from the dropdown lists. 2. Form hypothesis: How do you think predator and prey populations affect one another? 3. Predict: Based on your hypothesis, predict how changing the rabbit population will affect the other organisms at first. Write “Increase” or “Decrease” next to each “Prediction” in the table. Change Grass Snakes Hawks Doubling rabbit population Halving rabbit population 4. Test: Add rabbits until the population is about twice as large as it was (200% of balance). Click Play, and then Pause ( ) after approximately ONE month. Next to each “Result” line in the table, write “Increase” or “Decrease.” Click Reset and then halve the rabbit population (50% of balance). Record the results for this experiment in the table as well. A. How did doubling the rabbit population affect the grass, snakes, and hawks at first? B. How did halving the rabbit population affect the grass, snakes, and hawks at first? (Activity A continued on next page) Activity A (continued from previous page) 5. Predict: Predict how changing the snake and hawk populations will affect the other organisms within the first month. In the tables below, write your predictions. Change Grass Rabbits Hawks Doubling snake population Prediction: increase Result: the amount of grass went up Prediction: decrease Result: the rabbit population went down Prediction: increase Result: the hawk population went up Halving snake population Prediction: decrease Result: the amount of grass went down Prediction: increase Result: the rabbit population went up Prediction: decrease Result: the hawk population went down Change Grass Rabbits Snakes Doubling hawk population Prediction: decrease Result: the amount of grass went down Prediction: increase Result: the rabbit population went up a little Prediction: decrease Result: the snake population went down Halving hawk population Prediction: increase Result: the amount of grass went down Prediction: decrease Result: the rabbit population went down Prediction: increase Result: the snake population went up .........................................................................................continued....................................................................................................... [Show More]

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