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Item AP022006: Identify a food web and use it to write a prediction about the changes to an ocean ecosystem if the seaweed starts to die. (MC version)

Scientists are noticing that the seaweed that grows in the ocean along the northern coast of California is starting to die. They are worried that this could cause a problem with the amount of food available for sea turtles, sharks, shrimp, and stingrays in the ecosystem.

           
Images from Wikimedia Commons

The scientists see that:

  • shrimp and sea turtles eat seaweed
  • stingrays eat shrimp
  • sharks eat sea turtles and stingrays

They create a flow chart to show each of the animals in the ocean ecosystem and how food flows in the ecosystem. Arrows point toward the organism that is eating and away from the organism that is being eaten.


1. Which of the following flow charts best represents how the animals in the ecosystem get food?

A.
B.
C.
D.

2. What will happen to the amount of food available to the sea turtles if the seaweed continues dying? Explain why. (You should assume that no new plants or animals enter the ecosystem.)


3. What will happen to the amount of food available to the stingrays if the seaweed continues dying? Explain why. (You should assume that no new plants or animals enter the ecosystem.)


4. Scientists notice that the sharks in the ocean ecosystem are having a hard time performing their normal activities, such as moving around, reproducing, and growing. Could the decrease in the amount of seaweed in the ocean cause the sharks to not have the energy needed to perform their normal activities?

Write an argument for or against the idea that the dying seaweed caused the sharks to not have the energy needed for their normal activities. Support your argument using your flow chart and ideas about energy.


Percent of Points Earned
Chart showing distrubtion of responses for Item AP022006
Points Earned
  Avg. Earned Possible Percent
Q10.53153%
Q20.84242%
Q31.45436%
Q41.51438%
 
Overall Task Difficulty
  Total Points Earned Total Points Possible Total Percent
 4.341139%

n = 280

Note: The total percent is a weighted average based on the total number of points earned divided by the total number of points possible.