Commensalism is a type of symbiotic relationship where one organism benefits while the other is neither helped nor harmed. For example, barnacles often attach themselves to the shells of turtles. The barnacles gain a place to live and access to food in the water, while the turtle remains unaffected by their presence. This relationship is different from mutualism, where both organisms benefit, and parasitism, where one organism benefits at the expense of the other. Commensalism can be seen in various ecosystems, showcasing the diverse interactions between species, such as epiphytic plants growing on trees without harming them.