Science Assessment ~ Topics ~ Interdependence in Ecosystems ~ Item IE012011 ~ Student Performance

A national park is home to large populations of mountain lions, deer, rabbits, and grass. Recently, park rangers decided to introduce wolves to the park.

Mountain lions and wolves both eat deer and rabbits. Deer and rabbits both eat grass.

If the number of deer and rabbits eaten by mountain lions stays the same, what will happen to the grass after the wolves are introduced? Use only the relationships between the plants and animals described above.

The amount of grass will increase.
The amount of grass will stay the same.
The amount of grass will decrease until it is all gone.
The amount of grass will decrease, but some will remain.

Distribution of responses
Answer Choice		Overall	Grades		Gender		Primary Language
		n = 1396	6–8 n = 789	9–12 n = 605	Male n = 653	Female n = 711	English n = 1260	Other n = 103
A.	The amount of grass will increase.	55%	53%	57%	58%	52%	55%	51%
B.	The amount of grass will stay the same.	20%	19%	22%	19%	21%	21%	19%
C.	The amount of grass will decrease until it is all gone.	11%	13%	8%	11%	11%	11%	14%
D.	The amount of grass will decrease, but some will remain.	14%	15%	13%	12%	15%	14%	16%

Science Assessment

Item IE012011: Changes in a population in a food web (wolves) can affect populations of other organisms (grass) even if they are not directly connected in a feeding relationship.