1. Activity 84:Clam Catch Challenge  How might an introduction of a competing species, such as the invasive zebra mussels, affect a population of native clams? Key Vocabulary: Competition Native Species Invasive Species

2. Define the following in your notebooks: Competition  a contest for resources that can occur between organisms of the same species as well as between organisms of different species Native Species  a species found within a particular habitat Invasive species  an organism that is not native and has negative effects on our economy, our environment or our health

3. What do organisms need to live? Space Food Sunlight (if you are a plant) Water Remember that living and nonliving factors can affect population size.

4. If there are no changes in an ecosystem from year to year, would you expect populations to also stay the same? Remember from Activity 77 “Ups and Downs” that populations can fluctuate.

5. In our activity tomorrow, you are going to model a clam population over ten years. Do you expect the clam population to stay exactly the same? Do you expect a population of real clams to stay the same?

6. In round 1: Clams wear a wrist band Only one clam per circle Clams can only catch plankton with one hand and both feet must remain in their circle. Plankton begin in the safety zone. May not go around the ends of the clam beds. The goal is for plankton to get through the clam bed without being “eaten” (tagged) Tagged plankton, stay with your clam until told. Tagged plankton become clams. Clams that do not tag any plankton is considered dead and also becomes plankton.

7. Clam and Zebra Mussels

8. Round 2: Two mussels can occupy one circle, or one mussel and one clam. Two clams CAN NOT share a circle. Zebra mussels are better filter feeders so they can use two hands to tag plankton Zebra mussels will not wear wrist bands. Plankton tagged by zebra mussels, become zebra mussels and receive an arm band Plankton tagged by clams become clams and do not collect arm bands. Any clam or zebra mussel that does not tag a plankton dies and becomes a plankton

9. Reminders for the game Round 1 Clams 8 in the middle circles Can “tag” only using one hand If you tag the plankton, they become clams. If you don’t tag anything, you “die” and become plankton. Plankton Start in the Safety Zone Run across the lake to the other safety zone trying to avoid being tagged by a clam in 10 seconds. If you are tagged, you become a clam and stay in the middle circle.

10. Reminders for the game Round 2 Zebra Mussels Start with 3 Can use BOTH Hands. Wear a Red Band. 2 per circle or 1 with a Clam Clams Start with 8 Can only Use ONE Hand. Only 1 per circle

11. Record your data into your notebooks on SS 84.1 Once you have recorded your class data, Answer Analysis Questions 1, 2, 5 and 6 in your notebooks with your group!

12. Analysis Question #3 is for homework and will be graded using the OD Assessment and the AD Assessment.

13. Analysis #1 a.Should have made a line graph b.In general, the population fluctuated. But it did remain fairly steady between 6 and 14 clams. Over the first 2 years the population increased from 6 to 14. It then decreased to 8 clams by year 4. These types of variations continued to be observed for the remaining 6 years. Number of Clams

14. Analysis #2 The availability of plankton, or food, was the limiting factor that affected the size of the clam population. When more food was available, it was easier for clams to catch it and the clam population grew. When food was scarce, the clam population decreased, reducing competition for food allowing the plankton population to increase.

15. Analysis #5 A.In a real lake, non living factors such as: water temperature, amount of sunlight, pollution levels, availability of oxygen, and amount of suitable space are all factors that would affect the size of clam and zebra mussel populations B.Predators, competition between species, and food availability are living factors that might affect population size.

16. Analysis #6 See SS 77.2 After column #6-8