Ecologists divide freshwater ecosystems into bodies of running water and bodies of standing water.
In the latter the current slows and most suspended particles settle to the bottom. Lakes and ponds are bodies of standing water that will serve as the sources for water samples to investigate freshwater ecosystems. Protists, which comprise many of the organisms found in the water samples, are mostly single-celled microscopic organisms. They have a nucleus and other cell parts. Review usage and handling of a microscope during period 1.