A term for members of the phylum Arthropoda, largest in the animal kingdom. Arthropods are identified by a nonliving exoskeleton (an external skeleton), by segmented bodies, and by jointed appendages that appear in pairs. Among the classes with in this phylum are Arachnida (spiders, scorpions, ticks, and mites) and Insecta.
Displaying no symptoms of a disease or other condition.
The third-largest major, or obligatory, taxonomic classification rank, smaller than phylum but larger than order.
A symbiotic relationship in which one organism, the commensal, benefits without causing any detriment to the other organism, the host.
A protozoan in an in active state, encased in a protective outer membrane. Protozoa usually enter the bodies of hosts in the form of cysts.
The host in whosebody a parasite reproduces sexually. A parasite enters a definitive host either througha vector, an intermediate host, or through some other source, such as a water supply.
Parasites that live outside a host's body.
Parasites that live inside a host's body.
A cell that has a nucleus, as well as organelles (sections of the cell that perform specific functions) that are bound by membranes.
A term for a symbiotic relationship in which partners are capable of living apart.
The stomach and intestines.
The second-smallest major taxonomic classification rank, smaller than family and larger than species.
The term for an organism that provides a benefit or benefits to another organism in a symbiotic relationship of commensalism or parasitism. See also intermediate host and definitive host.
A creature that serves as host to a parasite, which it receives either directly (typically through the water supply) or from a vector before passing it on to a definitive host. Parasites do not reproduce sexually inside an intermediate host.
Masses of tissue at certain places in the body that act as filters for blood.
A term for a symbiotic relationship in which the partners, if they were separated, would be incapable of continuing to live.
A general term for any organism that depends on another organism for support, which it receives at the expense of the other organism.
A symbiotic relationship in which one organism, the parasite, benefits at the expense of the other organism, the host.
A biological discipline devoted to the study of parasites but primarily those among the animal and protist kingdoms. Parasitic bacteria, fungi, and viruses usually are studied within the context of infectious diseases.
A disease-carrying parasite, typically a microorganism.
The second-largest major taxonomic classification rank, smaller than kingdom but larger than class.
A term for members of the kingdom Protista, which includes algae (other than blue-green algae, which are monerans), slime molds (a group of about500 species that resemble fungi), and protozoa.
A term that refers to some 50,000 species of mobile protists.
A classification rank, smaller than that of phylum but larger than that of class, that is sometimes used to indicate a level between those two major ranks.
A biological relationship in which (usually) two species live in close proximity to each other and interact regularly in such a way as to benefit one or both of the organisms. Symbiosis may exist between two or more individuals of the same species as well as between two or more individuals representing two different species. The three principal varieties of symbiosis are mutualism, commensalism, and parasitism.
The area of the biological sciences devoted to the classification of organisms according to apparent commoncharacteristics.
A protozoan in a feeding stage, as opposed to a reproductive or resting stage.
An organism, such as aninsect, that transmits a pathogen to the body of a host.
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