84 Clam Catch

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84 Clam Catch Key Vocabulary competition fluctuation habitat introduced species population predator

84 Clam Catch What do organisms need to live? Record your answer in your notebook.

84 Clam Catch Imagine Imagine an ecosystem in which most things stay the same from year to year. There is no change in the types of species found there, and the average yearly rainfall, temperature, and other conditions stay about the same. Would you expect the population of each species to stay the same each year? Share your thoughts with the class.

84 Clam Catch Read the introduction and look for key ideas Predator and Prey

84 Clam Catch How might the introduction of a competing species, such as zebra mussels, affect a population of clams? Predator and Prey

84 Clam Catch Do you expect the population of clams to stay exactly the same in each year of the game? Do you expect a population of real clams to stay the same? Explain. Share your thoughts with the class.

84 Clam Catch Complete procedure part A Listen to your teacher to determine if you will represent a clam or plankton.

84 Clam Catch Class data

84 Clam Catch Was the population of clams the same from year to year? What prevented the population of clams from continuing to increase? Overall, was the population stable or unstable? Share your thoughts with the class.

84 Clam Catch What happens if there are more organisms in an ecosystem than resources? Do you have any examples of one species outcompeting another from your research on introduced species? Share your thoughts with the class.

84 Clam Catch Complete part B of the procedure Zebra mussels will be represented by students wearing red arm bands. Predict what your think will happen to the population of clams and zebra mussels over time.

84 Clam Catch How well do you think this activity modeled real populations? Share your thoughts with the class.

84 Clam Catch Analysis question 1 a. Graph the population of clams and zebra mussels over time from Part B of the Procedure. Use the same type of graph you used in Part A. Remember to label your axes and to title your graph. Use a key to show what represents the clam population and what represents the zebra mussel population.

84 Clam Catch SCORING GUIDE: Organizing Data

84 Clam Catch Analysis question 1 b. Look at your graph and describe how the population of clams changed over time.

84 Clam Catch SCORING GUIDE: Analyzing Data

84 Clam Catch Analysis question 2 What factor limited the size of the clam population?

84 Clam Catch Analysis question 3 a. Graph the population of clams and zebra mussels over time from Part B of the Procedure. Use the same type of graph you used in Part A. Remember to label your axes and to title your graph. Use a key to show what represents the clam population and what represents the zebra mussel population.

84 Clam Catch SCORING GUIDE: Organizing Data

84 Clam Catch Analysis question 3 b. Look at your graph and describe how the population of clams changed over time.

84 Clam Catch SCORING GUIDE: Analyzing Data

84 Clam Catch Analysis question 3 c. Look at your graph and describe how the population of zebra mussels changed over time.

84 Clam Catch SCORING GUIDE: Analyzing Data

84 Clam Catch Analysis question 4 a. What happened to the clam population after zebra mussels were introduced? b. Why did zebra mussels have this effect on the clam population? Explain.

84 Clam Catch Analysis question 5 a. In a real lake, what non-living factors might affect the size of clam and zebra mussel populations? List them. Hint: Go outside and look at an ecosystem around you. Observing an actual ecosystem may help you think of more factors. b. In a real lake, what living factors might affect the size of clam and zebra mussel populations? List them.

84 Clam Catch Analysis question 6 Fill in the “After” column for Statements 6–8 only on Sheet 77.2, “Anticipation Guide: Introduced Species—Zebra Mussels.” Did your thinking change?

84 Clam Catch How might the introduction of a competing species affect a population of clams? Predator and Prey

84 Clam Catch Key vocabulary definitions Competition - Interaction between organisms or species using the same limited resources, such as food and living space. Fluctuation - A change over time in size, numbers, or other characteristics.

84 Clam Catch Key vocabulary definitions Habitat - The specific environment where an organism lives based on what the organism requires to survive. Introduced species - A species that has been moved by humans from its normal habitat to a new habitat, either intentionally or by mistake.

84 Clam Catch Key vocabulary definitions Population - A group of the same species of organisms living in a specific location or habitat. Predator - An organism that kills another organism in order to eat it.

84 Clam Catch Are introduced species always successful? Introduce a mobile predator that eats only clams. Figure out how to modify the game to include this predator. Predict what you think will happen to the predator population and the clam population over time. Then test your ideas by playing the game for at least ten rounds.