Which type of biological interaction involves one species benefiting while the other is not significantly affected?

Commensalism is a type of biological interaction where one species benefits while the other is neither helped nor harmed significantly. In commensal relationships, the benefiting species may derive food, shelter, or support from the other, but the host species remains largely unaffected, which distinguishes it from other interactions.

For instance, consider barnacles attaching themselves to the shell of a turtle. The barnacles gain a place to live and access to water movement, which helps with feeding, while the turtle does not experience any significant benefit or detriment from the barnacles' presence. This illustrates that in commensalism, there is an asymmetry where the needs of one organism are met without impacting the other.

On the other hand, mutualism involves both species benefiting from the interaction, whereas parasitism is characterized by one species benefiting at the expense of the other. Competition revolves around two species competing for the same resources, which does not align with the concept of one benefiting without affecting the other. Thus, the defining feature of commensalism is the lack of significant impact on the host species while one organism reaps the benefits.