In response to Charles question as to how long a parasite must be
associated with a particular host before it becomes a commensal, ...
This seems to me that we have already forgotten the discussion
earlier this year regarding *virulence*. The dogma being questioned at
the time was do parasites evolve towards less virulence. Ewald (even
though Derek was not impressed) would argue that some parasites might
evolve which are highly virulent (Read *Hot Zone* for example).
Personally, I think that the working definition of a parasite found in
text books <organisms including round and flat worms, and protozoans>
leaves much to be desired because whether we admit it or not, this is
tantamount to saying that a parasite is what a parasitologists says it
is. It also begs the question of what are intracellular bacteria,
prions, spiroplasmas, and even more complicating of the question, what
are viruses.
Derek's offer of using endosymbiont is not a good idea. This
word literally implies living within. What about living attached
outside. Are barnacles parasites?
Maybe a parasite is an organism that takes from another. What is
taken should be left vague and so too, should the rate at which it is
taken. The is rate is only slower than a predator's rate of take which
is kill and consume at the spur of the moment. After all the word
parasite, literally means to sit at the table's side.
Steve
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/\ /\/ /######\ /#######\ ! Stephen G. Kayes, Ph.D. !
/\/ /\/ / / / ! Structural & Cellular Biology !
/\/ /\/ / / / ! University of South Alabama !
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The fact that an ostrich has wings has nothing to do with its inability
to fly. Pickeral
