Imagine that an ecosystem contains rabbits, foxes, wolves, and deer. The following predator-prey relationship exist:

Rabbits are eaten by foxes and wolves
Deer are eaten by wolves
Foxes are eaten by wolves

Select the animal whose absence would have the greatest negative effect on the ecosystem.

A. Deer

B. Wolf

C. Rabbit

D. Fox

The absence of wolves would have the greatest negative effect on the ecosystem.

Wolves are at the top of the food chain in this ecosystem and play a crucial role in regulating the populations of the other animals. If wolves were absent, the populations of rabbits and foxes would likely increase without any natural predation, which could lead to overgrazing by rabbits and a decrease in food availability for other species. The absence of wolves could also disrupt the balance of the predator-prey relationship, potentially leading to an uncontrolled increase in the population of deer, which could have negative effects on vegetation and ecosystem structure. Additionally, without wolves, there would be no natural control on the fox population, which could have cascading effects on the rabbit population.