Science Assessment ~ Items ~ AP021006

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

1. Create a flow chart that shows each of the animals in the ocean ecosystem and how food flows in the ecosystem. Your flow chart should include arrows to make it clear where each animal gets its food. Arrows should point toward the organism that is eating and away from the organism that is being eaten.

[Q1-AP21 Model]

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.

Details
Performance
NGSS

Topic: 3D Energy Tasks
Scoring Rubric: Q1; Student draws a flow chart that includes the relevant relationships

Arrow from sting ray to shark

Arrow from turtle to shark

Arrow from shrimp to sting ray

Arrow from seaweed to shrimp

Arrow from seaweed to turtle; Q2; 1. Student makes a valid prediction

The amount of food available to the sea turtles will decrease (direct effects)

2. Student supports their prediction using the model and/or evidence

Seaweed is food for sea turtles.; Q3; 1. Student makes a valid prediction

The amount of food available to the stingrays will decrease (indirect effects)

2. Student supports their prediction using the model and/or evidence

Seaweed is food for shrimp.

Shrimp are food for stingrays.

Note: Implying that seaweed is food for shrimp and shrimp are food for stingrays is acceptable.

Student either states or uses a general science idea

Organisms can only survive in environments in which their particular needs are met (i.e. if the shrimp’s food source is reduced, they will die). [links needs and survival]

Note: It is acceptable to write that the shrimp will leave the ecosystem and that’s why there is less food for the stingrays.

Student supports their prediction with reasoning

The decrease in seaweed will reduce the food source for shrimp, which means the shrimp will die and there will be less food for stingrays.; Q4; Student makes a valid claim

The dying seaweed caused the sharks to not have enough energy to move.

Note: An implied claim or a claim that doesn’t explicitly mention energy are acceptable.

Student supports their prediction using the model and/or evidence

The sharks’ food supply is affected by the seaweed. Examples of this include listing what each animal in the ecosystem eats to demonstrate sharks are linked to seaweed or citing the correct flow chart model showing how sharks are linked to seaweed in the food web

Sharks eat stingrays, stingrays eat shrimp, shrimp eat seaweed.

The animals that the sharks eat eat seaweed.

The model shows that sharks can trace their food source back to seaweed.

Note:Implying these relationships is acceptable and students do not have to list all.

Student either states or uses a general science idea

Food is a source of energy (i.e. the turtles and stingrays are sources of energy for the sharks or the sharks have less food and therefore less energy). [links food and energy]

Organisms can only survive in environments in which their particular needs are met (i.e. if the shrimp’s food source is reduced, they will die). [links needs and survival]

Student supports their claim with reasoning

The food for sharks can be traced back to seaweed, so when the seaweed dies sharks will end up having less food and, therefore, won’t have energy to move.

Note: Students may indicate that the shark’s food can be traced back to the seaweed by listing the connections in the food chain/web that link the shark and seaweed, noting that they are connected through the food web/chain, or making a statement that indicates the sharks’ food source is linked to the seaweed.

Percent of Points Earned

Chart showing distrubtion of responses for Item AP021006

Points Earned

	Avg. Earned	Possible	Percent
Q1	0.29	1	29%
Q2	0.78	2	39%
Q3	1.28	4	32%
Q4	1.21	4	30%

Overall Task Difficulty

	Total Points Earned	Total Points Possible	Total Percent
	3.56	11	32%

n = 392

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

Science and Engineering Practices: SEP2 Develop and/or use models to describe and/or predict phenomena.
Crosscutting Concepts: CC4 A system can be described in terms of its components and their interactions.
Disciplinary Core Ideas: LS1.C Food provides animals with the materials they need for body repair and growth and the energy they need to maintain body warmth and for motion.
LS2.A The food of almost any kind of animal can be traced back to plants. Organisms are related in food webs in which some animals eat plants for food and other animals eat the animals that eat plants. Some organisms, such as fungi and bacteria, break down dead organisms (both plants or plants parts and animals) and therefore operate as "decomposers." Decomposition eventually restores (recycles) some materials back to the soil. Organisms can survive only in environments in which their particular needs are met. A healthy ecosystem is one in which multiple species of different types are each able to meet their needs in a relatively stable web of life. Newly introduced species can damage the balance of an ecosystem.

Science Assessment

Item AP021006: Create a food web and use it to predict changes to an ocean ecosystem if the seaweed starts to die. (CR version)