They were considered formerly to be part of the protista family.
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The term protista was first used by Ernst Haeckel in 1866.
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Many conditions affect the levels or nature of pigments in plant, animal, some protista, or fungus cells.
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No fungi or protista have the classification, though only four species in those kingdoms have been evaluated by the IUCN.
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In that they derive from an endosymbiotic event, chloroplasts are similar to mitochondria, but chloroplasts are found only in plants and protista.
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More examples
Eukaryotic one-celled living organisms distinct from multicellular plants and animals: protozoa, slime molds, and eukaryotic algae
Protists are a diverse group of eukaryotic microorganisms. Historically, protists were treated as the kingdom Protista, which includes mostly unicellular organisms that do not fit into the other kingdoms, but this group is contested in modern taxonomy. ...
(Protists) are a taxonomic Kindgom (Protista) of eukaryotes, which include the ciliates, flagellates, amoeba, and algae. It is a very diverse group of organisms with both unicellular and multicellular forms, and are capable of everything from photosynthesis to predatory behavior. ...
(Protists) are grouped according to whether they are animal-like, plant-like, or fungus-like.
(protists) Group of animals differing from the rest (Metazoa and Parazoa) in consiting of one cell only, i.e. one continuous mass of cytoplasm, but resembling them and plants, and differing from bacteria, in having at least one well-defined nucleus, of eucaryotic type.
The kingdom protista contains a variety of different organisms, ranging from animal-like to fungi-like. These organisms have all been included to the same taxonomic kingdom for their simple construction, and most are unicellular species. ...
Organisms in this Kingdom are unicellular and have a true nucleus (eukaryotic). They may be heterotrophic or autothrophic (able to make their own food). They may also be motile or sessile.
Members of the Protista are generally unicellular, eukaryotic organisms, although some multicellular forms are also included. Some forms are responsible for causing disease in humans.
Kingdom composed of eukaryotes that are not classified as plants, animals, or fungus. This group displays the greatest variety.