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  1. Define symbiont (symbiote)
    Any organism spending a portion or all of its life intimately associated with another organism of different species
  2. What are the 4 categories of symbiosis with a description and example of each.  Include specific terminology for each member if necessary.
    • *note- overlapping is common
    • Phoresis: the larger host carries the smaller phoront.  Neither is physiologically dependent.
    • ex- bacteria on legs of fly, fungi on aquatic arthropods, barnacles on sharks
    • Commensalism: The commensal benefits, and the host is neither harmed nor benefits
    • ex- Hermit crabs carry sea anemones on their borrowed shells, cleaner shrimp, clownfish in sea anemones
    • Mutualism: both partners (mutuals) benefit and depend on eachother physiologically
    • ex- Termites and flagellates
    • ex- aquatic cleaners set up cleaning stations and attract large cooperating hosts
    • ex- Corals and algae (zooxanthellae)
    • Parasitism: the parasite lives at the expense of the host
    • Dependence can be temporary (feeding) or determinant (tapeworm)
  3. Obligate vs facultative parasites
    • Obligate: physiologically dependent on host and cannot survive if kept isolation (most parasites)
    • Facultative: mostly free living and not normally parasitic but can become so if accidentally encountered (few parasites)
    • ex- Naegleria and Micronema
  4. Define incidental parasite.  Give an example.
    • When a parasite enters or attaches to body of host other than its normal one. (AKA accidental parasite)
    • ex- bird flukes can live temporarily in the skin of humans (swimmer's itch)
  5. Define: ectoparasite, endoparasite, definitive host, intermediate host, paratenic host
    • Ectoparasite: if the parasite lives on the surface of its host or superficially embedded in the body surface
    • ex- tick, leech, fleas
    • Endoparasite: if the parasite lives internally (alimentary tract, liver, lungs, and urinary bladder)
    • ex- tapeworms, trematodes, etc
    • Definitive host: parasite attains sexual maturity and reproduce (AKA primary host)
    • Intermediate host: some development of the parasite occurs but in which id does not reach maturity (AKA secondary host)
    • ex-snails, insects, etc
    • Paratenic host: host is not required for the completion of the parasite's life cycle but utilized as a temporary refuge (vehicle) for reaching the definitive host (AKA transfer host)
    • ex- the thorny-headed worm uses an insect as the parantenic host (shrew) eats the intermediate host (insect) so that it can be transferred to the definitive host (owl)
    • *NOTE- no development occurs
  6. Define reservoir host, sylvatic reservoir host, domestic reservoir host, zoonosis, vector, hyperparasitism, verminous intoxication.  Give an example for each
    • Reservoir host: infected animals that serve as a source of human parasites without typically being symptomatic
    • ex- filarial worm transmitted to humans by mosquito from monkeys (sylvatic) and cats (domestic)
    • Sylvatic reservoir host: wild animal
    • Domestic reservoir host: domestic animal
    • Zoonosis: disease of humans caused by pathogenic parasite found in vertebrate animals (person to person transmission does not typically occur)
    • ex- Trichinella spiralis found in a variety of reservoirs (esp. pigs) and humans are infected by eating meat.
    • Vector: anything (living or non-living) that serves as a carrier of parasites
    • ex- bug, fish, water, air
    • Hyperparasitism: parasites hosting additional parasites
    • ex- Plasmodium in a mosquito
    • Verminous intoxication: poisoning of the host with toxic metabolic products
  7. How can parasites harm hosts?
    • Mechanical injury
    • Derviting nutritive substances such as blood, lymph, cytoplasm, digesting tissue fluid and host food
    • Poisoning the host with toxic metabolic products (verminous intoxication) leading to lethargy, bloating, hunger, allergies, gas, unclear thinking, weightloss, etc
Card Set:
2014-09-18 08:04:10
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