On 3 Apr 1995, Jeffrey Lotz wrote:
> In response to Zelmer
>> The term "endo-symbiotic" as a synonym of
> "not-free-living" of course does not
> include "ecto-symbionts". Therefore, if we
> are to use some form of it the correct term
> is "endo/ecto-symbiotic" a rather contrived
> word. "Endo/ecto-symbiont" does not seem to
> have many, if any advantages over the word
> "parasite".
There are also ecto- and endo- parasites, the prefix is locational. The
term symbiont encompasses both ecto and endosymbionts. It has the advantage
over the term "parasite" in that it implies "not-free-living" without
specifying an effect on the host...parasite defines the effect the symbiont
has, which is negative.
>> Whether the word "parasite" should be a
> synonym of "pathogen" or "not-free-living"
> or for that matter of something else is
> only of moderate interest.
"Pathogen" specifies that an organism is disease-causing. It is a *subset*
of the term parasite. Morbidity is not always the end result of parasitism,
the net negative effect can usually be less severe.
>> Now, it may be appropriate to call the
> things that parasitologists study
> "endo/ecto symbionts" or for that matter
> "rutabagas." However, regardless of what we
> call them the things that parasitoligists
> study are organisms that are
> "not-free-living." That is the way that
> most parasitologists use the term in their
> work and it is this aspect of their nature
> that holds the discipline of parasitology
> together. It is what being parasitic is all
> about.
I think that if you did a survey you would find that most parasitologists
study symbionts that have a net negative effect on their hosts...the
net negative effect is the unifying theme. Parasitologists study parasites.
It is rather a circular argument to say that a parasite is what a
parasitologist studies.
> However, "parasite" is more
> often used in the sense of
> "not-free-living" than it is as a synonym
> of "pathogen", at least among those that
> call themselves "parasitologists."
Not all "not-free-living" organisms are parasites, and not all parasites
are pathogens. Some would say that not all pathogens are parasites, but
I'm sure we would all agree that all parasites are "not-free-living".
Hope this clears things up.
Derek Zelmer, theoretical rutabegologist
