Massachusetts Comprehensive Assessment System (MCAS) Biology Practice Test

What does a predator-prey relationship entail?

1. The protection of one species by another

2. One organism consuming another organism

3. Both organisms living together harmoniously

4. Competition for the same resources

The correct answer is: One organism consuming another organism

A predator-prey relationship fundamentally involves one organism consuming another organism, which encapsulates the dynamic between a predator, the one that hunts, and the prey, the one that is hunted. This relationship is a key component of ecological systems, influencing population dynamics and food web structures. The predator benefits from this interaction by gaining energy and nutrients necessary for its survival and reproduction, while the prey serves as a food source, often leading to adaptations for escape or defense. In this context, the other choices do not accurately describe a predator-prey relationship. For instance, the idea of protection between species reflects a mutualistic relationship, which is distinct and not applicable here. The concept of harmonious cohabitation aligns more with symbiotic relationships, where both species benefit without harm, which is not the case in predator-prey dynamics. Lastly, competition for the same resources refers to situations where organisms vie for limited resources in their environment, which differs from the direct consumption aspect that clearly defines predator-prey interactions.