The type of ecological relationship that occurs when one species benefits while the other is harmed is known as parasitism. In this relationship, the parasite derives benefits, such as nutrients or habitat, at the expense of the host organism. This interaction can lead to various effects on the host, ranging from mild to severe harm, including disease or even death. Parasitism is common in nature and includes a variety of organisms, from microorganisms to larger animals. Understanding this dynamic is crucial for studying ecosystems, species interactions, and the overall balance of nature.