The food webs below model relationships among organisms in two ecosystems.
Oak Forest Food Web.
Wildcat, snake, hawk, deer, raccoon, skunk, butterfly, mouse, squirrel, grasshopper, grass, oak tree, wildflower. Grassland Food Web.
Fox, owl, small bird, snake, rabbit, mouse, grasshopper, grass.
Students were asked to make a claim supported with evidence to answer the question, “Which ecosystem would be most sustainable if all the grasses died from severe drought?” What claim is valid and supported by the evidence?
A
The forest ecosystem is most sustainable because there are more top predators.
B
The grassland ecosystem is most sustainable because there are fewer organisms that eat grass.
C
The forest ecosystem is most sustainable because most of the animals can eat other organisms.
D
The grassland ecosystem is most sustainable because there is less competition for food.
C
The forest ecosystem is most sustainable because most of the animals can eat other organisms.
This claim is supported by the complexity of the Oak Forest Food Web, where there are multiple levels of consumers that can feed on various organisms. In the grassland ecosystem, if all the grass were to die, there would be limited food sources for the organisms that primarily rely on grass, such as rabbits and grasshoppers. In contrast, the Oak Forest Food Web includes organisms such as raccoons, snakes, hawks, and wildcats that can feed on a variety of other organisms in the absence of grass. This diversity of food sources would make the forest ecosystem more resilient to changes in the availability of a particular food source like grass.