Science Assessment ~ Topics ~ Interdependence in Ecosystems ~ Item IE025004 ~ 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 following populations of organisms could be affected if the number of frogs changes?

Only the frog population could be affected.
Only the populations of plants, beetles, and bears could be affected.
Only the populations of beetles, hawks, bears, and owls could be affected.
The populations of all of the organisms shown in the diagram could be affected.

Distribution of responses
Answer Choice		Overall	Grades		Gender		Primary Language
		n = 1394	6–8 n = 784	9–12 n = 608	Male n = 652	Female n = 708	English n = 1258	Other n = 102
A.	Only the frog population could be affected.	6%	7%	5%	6%	6%	6%	9%
B.	Only the populations of plants, beetles, and bears could be affected.	9%	10%	9%	10%	9%	9%	14%
C.	Only the populations of beetles, hawks, bears, and owls could be affected.	37%	39%	34%	38%	36%	37%	42%
D.	The populations of all of the organisms shown in the diagram could be affected.	48%	44%	53%	46%	50%	48%	35%

Science Assessment

Item IE025004: 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 (woodland ecosystem).