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Protists do not form a natural group, or clade, but are a paraphyletic grouping of all descendants of the last eukaryotic common ancestor excluding plants, animals, and fungi. Protists were historically regarded as a separate taxonomic kingdom known as Protista or Protoctista.
Systematists today do not treat Protista as a formal taxon, but the term "protist" is still commonly used for convenience in two ways. [22] The most popular contemporary definition is a phylogenetic one, that identifies a paraphyletic group: [23] a protist is any eukaryote that is not an animal, (land) plant, or (true) fungus; this definition [24] excludes many unicellular groups, like the ...
The resulting five-kingdom system, proposed in 1969 by Whittaker, has become a popular standard and with some refinement is still used in many works and forms the basis for new multi-kingdom systems. It is based mainly upon differences in nutrition ; his Plantae were mostly multicellular autotrophs , his Animalia multicellular heterotrophs ...
A protist (/ ˈ p r oʊ t ɪ s t /) is any eukaryotic organism (one with cells containing a nucleus) that is not an animal, plant, or fungus.The protists do not form a natural group, or clade, since they exclude certain eukaryotes with whom they share a common ancestor; [a] but, like algae or invertebrates, the grouping is used for convenience.
[10] [11] The taxa "animal kingdom" (or kingdom Animalia) and "plant kingdom" (or kingdom Plantae) remain in use by some modern evolutionary biologists. The initial targets of Cavalier-Smith's classification, the protozoa were classified as members of the animal kingdom, [12] and many algae were regarded as part of the plant kingdom. With ...
Protistology is a scientific discipline devoted to the study of protists, a highly diverse group of eukaryotic organisms. All eukaryotes apart from animals, plants and fungi are considered protists. [1]
Linnaeus 1735 [1] Haeckel 1866 [2] Chatton 1925 [3] Copeland 1938 [4] Whittaker 1969 [5] Woese et al. 1990 [6] Cavalier-Smith 1998, [7] 2015 [8] 2 kingdoms 3 kingdoms 2 empires: 4 kingdoms: 5 kingdoms
Excavates were formerly considered to be included in the now obsolete Protista kingdom. [6] They were distinguished from other lineages based on electron-microscopic information about how the cells are arranged (they have a distinctive ultrastructural identity). [4] They are considered to be a basal flagellate lineage. [7]