Three interesting facts about the Kingdom Protista are that all members are eukaryotic, they are not plants, animals or fungi and they are usually single celled. Living things that do not fit into any other Kingdom are classified in this Kingdom and are called protists.
Eukaryotic means having a nucleus. The nucleus is the brain of a cell. Some protists have just one nucleus. Others, such as ciliophora, have one macronucleus and several micronuclei that are smaller in size. Protists are organized into three groups based on how they obtain nutrition: Protozoa, Algae and Fungus-like Protists.
Protozoa are the most animal-like and obtain food by a process called phagocytosis. Some have mouths used to ingest food, while others surround and engulf prey in a process called pseudopodia. The Protozoa group has four Divisions: Rhizopoda, Apicomplexa, Zoomastigophora and Ciliophora. Rhizopoda are unicellular and have pseudopodia, or extensions of the nucleus. Apicomplexa are parasites with complex life cycles, forming miniscule, infectious spores. The Zoomastigophora Division contains independent and symbiotic organisms as well as parasites. Ciliophora are solitary, reside in fresh water and move using cilia. Of all the Protozoans, they have the most complex structure and organization.
Algal Protists are plant like, using photosynthesis to collect nutrients. Divisions include Dinoflagellata, Euglenophyta, Chlorophyta, Phaeophyta and Rhodophyta. Dinoflagellata are commonly found among plankton, and in very large numbers, they cause a "Red Tide" effect. Euglenophyta members have a flagellum used for movement. They perform photosynthesis when light is present and phagocytosis otherwise. Chlorophyta are also known as "green algae," colored from chloroplasts and pigmentation. Phaeophyta, or "brown algae," are multicellular, live in temperate marine zones and coastal areas. Rhodophyta are also multicellular marine dwellers but are usually found deeper in tropical oceans.
Fungus-like protists have just one Division called Myxomycota and are often called "slime molds." They absorb nutrients from their environment through phagocytosis.