What happens is some of the germs kill the host and some of them are less
potent and don't kill the host. The ones that kill drop out of the race. The
ones that co-exist go on to infect again. They don't change in mid-stream
they start out less potent. I hope you knew this Pete.

My point was that not all populations contain this potential.
Obviously for a host -parasite relationship to develop all the
virulent parasites and/or susceptible hosts will die first. Those
hosts and guests will not adapt. What would remain is less virulent
and/or more resistant guests and hosts. But the advent of such a
relationship is by no means assured as evidenced by the experiment on
Santa Cruz Island. It has taken place in populations of Apis cerana
and Apis mellifera scutellata.

My point was that while humans can use foresight to avoid killing the
goose that lays the golden egg, "microbes" cannot. The problem with
these discussions is that if you go into great detail and cover all
the bases, the post is so long nobody reads it. But if you leave
anything out somebody always pops in and says "Did you not KNOW
that?".

-- 
Peter L Borst
Danby, NY  USA
42.35, -76.50
http://picasaweb.google.com/peterlborst

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