The term for an ecological relationship where one organism benefits and the other is unaffected is called commensalism. In this type of interaction, one species derives some benefit, such as shelter or nourishment, while the other neither gains nor suffers any significant effects. An example of commensalism includes barnacles attaching to whales; the barnacles benefit from transportation to different feeding areas, while the whale remains largely unaffected. Understanding commensalism is essential for studying ecological relationships and biodiversity, as it highlights the complex interactions that shape ecosystems.