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another defini post

derek a. zelmer zelmeda4 at WFU.EDU
Wed Mar 29 07:36:03 EST 1995

On 1 Mar 1995, Jeffrey Lotz wrote:

> Even on sematic (rather than empirical) grounds, I would argue 
> against the restriction of parasite to pathogen. If we restrict 
> the use of parasite to pathogen then we are left without a word 
> to apply to organisms that are not-free-living. Typically 
> symbiosis is used to encorporate interspecific relationships 
> including mutualist-commensal-parasite. However, symbionts 
> usually include nest-parasites, cleaner fish, cattle egrets and 
> other organisms that live in close association with another 
> organism but are essentially free-living. Given this situation 
> we need a word that means not-free-living, that world should be 
> "parasite". We already have a word for a not-free-living 
> organism that does harm to its habitat, that word is pathogen.

I think that removing host damage from the definition of a parasite only 
creates more confusion. Mutualism and commensalism involve completely 
different life history strategies that follow differnt pathways of 
selection . In the case of parasites, harm to the intermediate host is often
required for transmission, a situation that would be untenable for a mutualist. 
If you are looking for a word to encompass non-freeliving organisms I 
would be happy to lend you "endosymbiont". I know it just adds to the 
list of jargon, but I don't think that the term parasite should be 
expanded to include commensals and mutualists.

			Derek A. Zelmer

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