Original Project
Interdependence in Ecosystems
Item IE034005: Changes in a population (rabbits) may affect populations that are not directly connected by a feeding relationship (crickets) even if they are several steps away and not within the same chain in a food web.
The diagram below shows the feeding relationships between populations of plants and animals in an area. The arrows point from the organisms being eaten to the organisms that eat them.
Most of the rabbits in this area are killed. If the number of hawks does not change, what could happen to the number of crickets and why? Use only the relationships between the plants and animals shown in the diagram.
- The number of crickets would decrease because fewer rabbits could result in a decrease in the number of individuals in all of the populations of organisms in this diagram.
- The number of crickets could decrease because with fewer rabbits for the hawks to eat, the hawks would eat crickets instead.
- The number of crickets could increase because with fewer rabbits for the hawks to eat, the hawks would eat more frogs, so there would be fewer frogs to eat the crickets.
- The number of crickets would not be affected by the number of rabbits because crickets are not connected by an arrow to rabbits in the diagram.
Answer Choice |
Overall |
Grades |
Gender |
Primary Language |
||||
|---|---|---|---|---|---|---|---|---|
| n = 1481 |
6–8 n = 863 |
9–12 n = 616 |
Male n = 697 |
Female n = 767 |
English n = 1340 |
Other n = 104 |
||
| A. | The number of crickets would decrease because fewer rabbits could result in a decrease in the number of individuals in all of the populations of organisms in this diagram. | 10% | 10% | 10% | 11% | 10% | 10% | 10% |
| B. | The number of crickets could decrease because with fewer rabbits for the hawks to eat, the hawks would eat crickets instead. | 14% | 15% | 12% | 14% | 14% | 13% | 20% |
| C. | The number of crickets could increase because with fewer rabbits for the hawks to eat, the hawks would eat more frogs, so there would be fewer frogs to eat the crickets. | 56% | 51% | 62% | 57% | 54% | 57% | 42% |
| D. | The number of crickets would not be affected by the number of rabbits because crickets are not connected by an arrow to rabbits in the diagram. | 20% | 24% | 15% | 19% | 22% | 20% | 28% |