Science Assessment ~ Topics ~ Interdependence in Ecosystems ~ Item IE026004 ~ Student Performance

The diagram below shows the feeding relationships between populations of organisms in an area. The arrows point from the organisms being eaten to the organisms that eat them.

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

Only the populations of large fish, seals, and killer whales would be affected.
The populations of all of the organisms except the killer whales would be affected.
Only the populations of shrimp, large fish, and small fish would be affected.
The populations of all of the organisms would be affected.

Distribution of responses
Answer Choice		Overall	Grades		Gender		Primary Language
		n = 1393	6–8 n = 782	9–12 n = 609	Male n = 651	Female n = 708	English n = 1256	Other n = 103
A.	Only the populations of large fish, seals, and killer whales would be affected.	5%	6%	3%	6%	4%	5%	5%
B.	The populations of all of the organisms except the killer whales would be affected.	9%	10%	7%	10%	8%	9%	11%
C.	Only the populations of shrimp, large fish, and small fish would be affected.	14%	15%	12%	15%	13%	13%	26%
D.	The populations of all of the organisms would be affected.	73%	69%	77%	70%	75%	74%	58%

Science Assessment

Item IE026004: Changes in a population may affect populations that are not directly connected by a feeding relationship even if they are several steps away in a food web (ocean ecosystem).