Definition: Protists are organisms in the kingdom Protista. These organisms are eukaryotes, meaning they are made up of single or multiple cells which all contain a nucleus enclosed by a membrane. The protists are a diverse group of eukaryotes that cannot be classified as animals, plants, or fungi. Organisms in the Protista kingdom include amoebae, red algae, dinoflagellates, diatoms, euglena and slime molds. Also Known As: Protista
One type of protist in the marine environment is Irish moss, which is a species of red algae. Diversity of Protists
Protists are Eukaryotes that are not fungi, plants, or animals. This polyphyletic group includes a wide variety of organisms. Most groups of protists are unicellular but some are multicellular. Molecular evidence suggests that protists include several different lineages and therefore is not a kingdom. Some lineages are more closely related to either Fungi, plants, or animals than they are to other protist groups. Plants,fungi,and animals evolved from protist ancestors.
Protists are a very diverse group and include organisms that range in size from single cells to complex structures more than 100 meters long. They show a variety of reproductive and nutritional strategies. Some protists are photoautotrophs, others ingest food (heterotrophs) or they release digestive enzymes into the environment and absorb organic molecules (saprotrophs). Some protists are both autotrophs and heterotrophs (mixotrophs). Most protists are aquatic but they are also found in moist terrestrial environments. They are important components of plankton in many aquatic food chains. Some groups of photoautotrophic protists are referred to as algae (green algae, red algae, brown algae, golden algae). The word algae is not used as a taxonomic category. Plasmodial (Acellular) Slime Molds
Acellular slime molds are diploid, multinucleate masses that creep along the substrate and phagocytize dead organic...