Answer Key to Whales Task

The target level for each question refers to a level on either the Ecosystems or the Argumentation learning progression.

Correct answers are underlined.

Instructions: Read the information below and look at the illustration of the food web, then answer the questions

The arrows point from the organisms being eaten to the organisms that eat them.

Target level: Ecosystems level 2a

1. Using only the relationships between the organisms shown in the diagram, which two populations would be the first affected if the seaweed were removed?

A. Seals, killer whales

B. Large fish, dolphins

C. Shrimp, small fish

D. Small fish, dolphins

Target level: Ecosystems level 3

2. What would happen to the killer whale population if the shrimp were removed from the ecosystem? The killer whale population would most likely...

A. Increase briefly and then return to the normal level

B. Stay the same and eat penguins, seals, and dolphins

C. Decrease for a short time and then return to the normal level

D. Be impossible to predict

Target level: Ecosystems level 2c

3. If shrimp were removed, which of the following changes would help stabilize the ecosystem? The ecosystem would be most likely to stabilize if...

A. killer whales eat fewer dolphins.

B. the population of large fish decreases.

C. seals eat more penguins.

D. penguins eat small fish.

Target level: Argumentation level 2b

4. Imagine there was a sudden drop in the population of small fish.

Chris says: "I think that the penguins would not be affected because penguins don't eat small fish."

Jeff says: "I think the penguins would be affected."

A. The food web shows that when the small fish die, seals will lose a food source and may eat more penguins and large fish.

B. Several reliable books and videos describe penguin populations getting larger in Antarctica.

C. A poll showed that most students in the class think penguins will be affected.

D. Several videos and pictures of dead penguins show them laying next to small dead fish that lived with the penguins in the same ecosystem.

A species of snail, which eats seaweed only, was introduced into the ecosystem. Seals, penguins and large fish will eat the snail.

The graph below shows what happens to three of the species in the ecosystem before, during and after the introduction of snails.

Target level: Ecosystems level 3

5. Based on the relationships shown in the food web, which population is shown by the "Unknown organism population size" line in the graph?

A. Shrimp

B.. Small fish

C. Dolphins

D. Large fish

Target level: Ecosystems level 3

6. If we keep monitoring this ecosystem, and there are no other major disruptions, what would we expect to happen to the seaweed and snails?

A. The populations of seaweed and snails will recover immediately.

B. The populations will return to their original levels by year 15.

C. The populations of seaweed and snails will increase and decrease from year to year.

D. The populations of seaweed and snails will decrease a lot or disappear.