In biology/ecology, parasitism is a non-mutual relationship between species, where one species, the parasite, benefits at the expense of the other, the host. Traditionally parasite (in biological usage) referred primarily to organisms visible to the naked eye, or macroparasites (such as helminths). Parasites can be microparasites, which are typically smaller, such as protozoa,[1][2]viruses, and bacteria.[3] Examples of parasites include the plants mistletoe and cuscuta, and animals such as hookworms.
In biology/ecology, parasitism is a non-mutual relationship between species, where one species, the parasite, benefits at the expense of the other, the host. Traditionally parasite (in biological usage) referred primarily to organisms visible to the naked eye, or macroparasites (such as helminths). Parasites can be microparasites, which are typically smaller, such as protozoa,[1][2]viruses, and bacteria.[3] Examples of parasites include the plants mistletoe and cuscuta, and animals such as hookworms.
The Polychaeta/ˌpɒlɪˈkiːtə/, also known as the bristle worms or polychaetes, are a paraphyletic class of annelid worms, generally marine. Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called chaetae, which are made of chitin. As such, polychaetes are sometimes referred to as bristle worms. More than 10,000 species are described in this class. Common representatives include the lugworm (Arenicola marina) and the sandworm or clam wormAlitta.
