Symbiosis and Parasitism in Marine Organisms Flashcards

This set covers vocabulary regarding marine symbiotic and parasitic associations, includes definitions of relationship types, metrics for measuring infection, and life cycle terminology.

Symbiosis

A close, long-term association between two or more different species of organisms; these relationships can be facultative or obligatory.

Symbionts

The specific organisms involved in a symbiotic relationship.

Mutualism

A form of symbiosis in which two species associate for their mutual benefit, often denoted as ($+/+$).

Commensalism

An association whereby there is a clear example of benefit to one member (the commensal) while not harming the other (the host), often denoted as ($+/0$).

Inquilinism

A subdivision of commensalism in which one animal lives in the home of another, or in its digestive tract, without being parasitic.

Zooxanthellae

A group of algal symbionts characterized by brown, yellow, or golden cells.

Zoochlorellae

A group of algal symbionts characterized by green cells.

Cyanellae

A group of algal symbionts characterized by blue-green cells.

Endozoites

Commensal organisms that live inside other organisms.

Epizoites

Commensal organisms that live on the surface of other organisms.

Parasitism

A close association between two organisms in which the parasite depends on the host to derive benefit while causing the host some harm, often denoted as ($+/-$).

Prevalence

The proportion of infected hosts at a given time; for example, 4 infected out of 10 total equals a prevalence of $0.4$ or $40\%$.

Intensity

The number of parasite individuals of a particular species found in each individual infected host.

Mean Intensity

The total number of individuals of a particular parasite species in a sample divided by the number of infected individual hosts in that sample.

Abundance

The total number of individuals of a particular parasite species in a sample divided by the total number of individual hosts (both infected and uninfected) in the sample.

Direct Life Cycle

A parasitic life cycle that involves only the definitive host (adult stage) and larval stages, without intermediate hosts.

Indirect Life Cycle

A parasitic life cycle involving a definitive host and one or more intermediate hosts (e.g., Trematodes).

Definitive Host

The host in which the parasite reaches the adult stage and undergoes sexual reproduction.

Intermediate Host

A host required for parasite development, but in which the parasite does not reach sexual maturity; often labeled as 1st (L1) or 2nd (L2) intermediate hosts.

Paratenic Host

A host that is not required for the parasite's development but serves as a 'transport' host to help the parasite reach its next host.

Feminization

A process where certain parasites (such as Microsporidia or Sacculina) convert genetic males into phenotypic females or cause them to resemble and function as females.

Vertical Transmission

The transmission of parasites from parent to offspring via the gamete (usually maternal).

Sacculina sp.

A genus of Rhizocephala that parasitizes crabs, causing extensive damage to endocrine organs, sterilization, and behavioral changes like egg mimicry.