Re: Habitat of selected Protists

Dear Jim:

    Interesting question...  I guess the easiest answer to that is that it 
depends on which species.  The zoomastigote's and zooflagellate's main habitat 
is fresh water. 
 
    Many of the zooflagellates are free living.  For example, the 
choanoflagellates, can either be solitary or colonial.  Others are 
important human and animal parasites.  Examples include Trypanosoma, 
Giardia and Leishmania.  However, until they infect their hosts, in this 
case humans, most of their time is spent in freshwater.  Upon infection, 
they grow primarily in the blood stream and can use their flagella to 
propel themselves.

   On the other hand very few of the ciliates are parasitic.  Most are free 
living in both fresh and marine waters.  Examples include the paramecium,  
tetrahymena and vorticella.  Some ruminant animals for example may contain 
obligately anaaerobic ciliates in their forestomach, but again most are 
free-living.

Hope this answers your questions.

Rob Welton