What term describes an interaction in which one species benefits while the other is harmed or decreased in number?

• A. Exploitative Interaction
• B. Symbiosis
• C. Resource Partitioning
• D. Competition

Answer: (A)

In ecology, interactions where one species benefits while the other is harmed or decreases in number are called exploitative interactions. Here, the consumer gains energy or resources, while the other species loses those resources and often experiences reduced fitness or population decline. Classic examples include predation, parasitism, and herbivory—think of a predator catching prey, a parasite feeding on a host, or herbivores consuming plants. This is different from symbiosis as a broad idea, which covers long-term close associations that can be mutualistic, commensal, or parasitic; not all of those involve a clear cost to one partner. It’s also distinct from resource partitioning, which is about sharing resources to reduce competition, and from competition itself, where both sides are harmed by the struggle for limited resources. So the term that best describes a +/− interaction is exploitative interaction.