What term describes a relationship where one organism benefits while the other is harmed?

The term that describes a relationship where one organism benefits while the other is harmed is known as parasitism. In this type of relationship, the parasite derives benefits such as nutrients or shelter from its host, which often suffers from the association, experiencing harm or detriment as a result of the parasite's activities. This dynamic is critical in ecological studies because it illustrates the complex interactions within ecosystems and the impact one organism can have on another.

In contrast, commensalism represents a relationship where one organism benefits while the other is neither helped nor harmed. Mutualism involves both organisms benefiting from the relationship, creating a scenario where the interaction is advantageous to both parties. Lastly, competition occurs when two organisms vie for the same resources, potentially leading to harm for both if the resources are limited, but it does not fit the criteria of one benefiting at the expense of the other. Thus, parasitism accurately captures the essence of the specified relational dynamics.