What is parasitism?

Parasitism is a biological interaction where one organism, the parasite, benefits at the expense of another organism, the host, which is harmed in the process. This exploitative relationship is typically characterized by the parasite deriving nutrients or other benefits from the host, leading to detrimental effects on the host's health, growth, or fitness.

For instance, in cases such as tapeworms in a host's intestines or fleas on a dog, the parasite thrives by drawing resources from the host, who suffers as a consequence. This dynamic illustrates the fundamental nature of parasitism: it fundamentally relies on the imbalance of benefit, with one organism significantly benefitting while the other experiences negative effects. Understanding this relationship is essential in ecology, as it demonstrates the complexities of interactions among species and their roles within ecosystems.