What are protists?
   
  Because itís easier to use illustrations instead of words, the pictures above show representatives of this complex group of organisms. They all have in common that they need water to live in. Most of them are very small and it requires a microscope to discover them. In the banner we see from left to right: testate amoebae, a green alga, a red alga and a golden alga.

A few characteristics of protists are:
-The organization of protists is mostly unicellar or in chains of cells without a functional differenciation.
-All cells have organelles for feeding, all kinds of metabolism, osmoregulation and probably defense.
-They have sizes between a few micrometers (some flagellates) to some millimeters (e. g. Spirostomum species, a ciliate).
-The multicellular organized protest groups of brown and red algae and some species of slime moulds may reach sizes of up to several square meters.

   
  Different to animals and higher plants protists have no sexual reproduction with embryogenesis. But, other than bacteria, their cells also have a nucleus which controls vegetative and generative life processes. A more detailed definition is e. g. at Wikipedia (protists), for a detailed taxonomic overview look at micro*scope, a database hosted at the Bay Paul Marine Center in Woods Hole/Massachusetts.
 
  © Wolfgang Bettighofer 2009 - 2011