What term describes a relationship between two organisms where one benefits and the other is unaffected?

The term that describes a relationship between two organisms in which one organism benefits while the other is unaffected is commensalism. In this type of relationship, one species, often referred to as the commensal, derives some benefit, such as food, shelter, or transportation, while the other species, known as the host, neither benefits nor is harmed in any significant way. This balance illustrates how diverse interactions can be in an ecosystem, with some relationships not involving direct competition or harm to the other party involved. For example, barnacles attaching to the shell of a turtle is a classic example of commensalism; the barnacles gain a place to live, while the turtle is largely indifferent to their presence. Understanding this concept helps clarify how different organisms coexist and interact in their environments.