Protista - Background, Classification, Protozoa, Algae, Slime Molds And Water Molds, Disease-causing Protists

The Kingdom Protista is the most diverse of all six kingdoms. There are more than 200,000 known species of protists with many more yet to be discovered. The protists can be found in countless colors, sizes, and shapes. They inhabit just about any area where water is found some or all of the time. They form the base of ecosystems by making food, as is the case with photosynthetic protists, or by themselves being eaten by larger organisms. They range in size from microscopic, unicellular organisms to huge seaweeds that can grow up to 300 ft (100 m) long.