They have flagella for locomotion See more. All protozoans are eukaryotes and therefore possess a “true,” or membrane-bound, nucleus. Protozoa are single celled organisms. Protozoa Classification and Examples. There is a great deal to know about their classification, characteristics and more. Mastigophora or Flagellates: They are parasites or free-living. It is a loose assemblage of different groups of unicellular organisms and they do not belong to a monophyletic Unease, probably shares a member of polyphyletic lineases. In some newer schemes, however, most algae are classified in the kingdoms Plantae and Chromista , and in such cases the remaining forms may be classified as a kingdom Protozoa. They are believed to be a part of the microbial world as they are unicellular and microscopic. Definition: Unicellular or acellular, eukaryotic and com­monly motile heterotrophic organisms are called Protozoa. Protozoan, organism, usually single-celled and heterotrophic (using organic carbon as a source of energy), belonging to any of the major lineages of protists and, like most protists, typically microscopic. Protozoa are divided into four major groups based on the structure and the part involved in the locomotion: 1. They live in a wide variety of moist habitats including fresh water, marine environments and the soil. Moreover, they are herbivores, carnivores, and omnivores. Protozoa is a phylum having unicellular heterotrophs. Protozoa. Protozoa are single-celled organisms without cell walls. Protozoa. home >> biology >> definition They belong among the eukaryotes , and are often grouped in the kingdom Protista together with the plant-like algae . Protozoa [pro″to-zo´ah] a subkingdom (formerly a phylum) comprising the unicellular eukaryotic organisms; most are free-living, but some lead commensalistic, mutualistic, or parasitic existences. Protozoa is a single cell animal that we can find in every possible habitat on earth. Protozoa definition, a major grouping or superphylum of the kingdom Protista, comprising the protozoans. The word protozoa comes from the word protos, which was Greek for "first," and zoia which meant "animal." Protozoa are non-phototrophic, unicellular, eukaryotic microorganisms with no … Before then, the microscopic protozoa, defined by their organelles, were unable to be fully appreciated. It comes under Kingdom Protista. They come in many different shapes and sizes ranging from an Amoeba which can change its shape to Paramecium with its fixed shape and complex structure. It was first coined in the 1800s. Protozoa (meaning "first animals") are heterotrophic, single-celled or colonial eukaryotes. Furthermore, the scientist has described more than 50 thousand species of Protozoa. The group of organisms known as 'protozoa' are defined by a few of their shared characteristics. Learn more about it. 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