What characterizes commensalism in ecological relationships?

Commensalism is characterized by a specific type of ecological relationship in which one species derives benefit while the other species experiences no significant advantage or disadvantage. In this relationship, the benefiting species may receive resources, shelter, or transportation without negatively impacting the other species involved. A prime example of commensalism is seen with barnacles that attach themselves to the shells of turtles. The barnacles gain mobility and access to nutrient-rich waters while the turtle remains largely unaffected.

The defining feature of commensalism is that the non-benefiting species does not face harm or gain a benefit; it exists neutrally in the relationship. This distinguishes it from mutualism, where both species benefit, and parasitism, where one species benefits at the expense of the other. Understanding commensalism helps illustrate the complexities of interactions within ecosystems and the various ways species coexist.