Unikonts
Scientific classification
Domain: Eukaryota (unranked) Unikonta
Supergroups
Opisthokonta Amoebozoa Scientific classification or biological classification is a method by which biologists group and categorize species of organisms. ... Kingdoms Animalia - Animals Fungi Plantae - Plants Protista Alternative Phylogeny Unikonta    Opisthokonta    Amoebozoa Bikonta    Apusozoa    Cabozoa       Rhizaria       Excavata    Corticata       Archaeplastida       Chromalveolata Animals, plants, fungi, and protists are eukaryotes (IPA: ), organisms with a complex cell or cells, where the genetic material is organized into a membrane-bound nucleus or nuclei. ... Subgroups Kingdom Animalia Kingdom Fungi Choanozoa Choanoflagellates Corallochytrids Mesomycetozoea Nucleariids The opisthokonts (Greek: (opisthō-) = rear, posterior + (kontos) = pole i. ... Subgroups Mycetozoa(slime moulds) Archamoebae    Pelobiontida    Entamoebida Gymnamoebia Various others The Amoebozoa are a major group of amoeboid protozoa, including the majority that move by means of internal cytoplasmic flow. ...

Unikont is a eukaryotic cell with a single flagellum, at least ancestrally. Current research suggests that a unikont was the ancestor of opisthokonts and Amoebozoa, and a bikont (a eukaryotic cell with two flagella) was the ancestor of Archaeplastida, Excavata, Rhizaria, and Chromalveolata. The unikonts also have a triple-gene fusion that is lacking in the bikonts, and a single centriole (Cavalier-Smith, 2002, 2006). (Some unikonts have two centrioles but their orgins are developmentally different than in the bikonts, indicating convergent evolution (Cavalier-Smith 2006). The three genes that are fused together in the unikonts but not bacteria or bikonts encode enzymes for synthesis of the pyramidine nucleotides: carbamoyl phosphate synthase, dihydroorotase, aspartate carbamoyltransferase (Cavalier-Smith 2006). This must have involved a double fusion, a rare pair of events that is unlikely to be reversed, further supporting the shared ancestry of Opisthokonta and Amoebozoa. Kingdoms Animalia - Animals Fungi Plantae - Plants Protista Alternative Phylogeny Unikonta    Opisthokonta    Amoebozoa Bikonta    Apusozoa    Cabozoa       Rhizaria       Excavata    Corticata       Archaeplastida       Chromalveolata Animals, plants, fungi, and protists are eukaryotes (IPA: ), organisms with a complex cell or cells, where the genetic material is organized into a membrane-bound nucleus or nuclei. ... Drawing of the structure of cork as it appeared under the microscope to Robert Hook from Micrographia which is the origin of the word cell. Cells in culture, stained for keratin (red) and DNA (green). ... A flagellum (plural, flagella) is a whip-like organelle that many unicellular organisms, and some multicellular ones, use to move about. ... Subgroups Mycetozoa(slime moulds) Archamoebae    Pelobiontida    Entamoebida Gymnamoebia Various others The Amoebozoa are a major group of amoeboid protozoa, including the majority that move by means of internal cytoplasmic flow. ... A Bikont is a eukaryotic cell with two flagella. ... The Archaeplastida are a major line of eukaryotes, comprising the land plants, green and red algae, and a small group called the glaucophytes. ... This article is about the protist group called excavates. ... The Rhizaria are a major line of protists. ... Phyla Heterokontophyta Haptophyta Cryptophyta Alveolata Ciliophora Apicomplexa Dinoflagellata Chromalveolata is a eukaryote supergroup first proposed by Thomas Cavalier-Smith as a refinement of his kingdom Chromista, which was first proposed in 1981. ... A centriole in biology is a barrel shaped microtubule structure found in most animal cells and algae though not frequently in plants. ... A nucleotide is a chemical compound that consists of a heterocyclic base, a sugar, and one or more phosphate groups. ...

References

• Thomas Cavalier-Smith (2002). "The phagotrophic origin of eukaryotes and phylogenetic classification of Protozoa". Int. J. Syst. Evol. Microbiol. 52: 297–354. 

• Thomas Cavalier-Smith (2006). "Protist phylogeny and the high-level classification of Protozoa". European Journal of Protistology 39 (4): 338-348. 

• Alexandra Stechmann and Thomas Cavalier-Smith (2003). "The root of the eukaryote tree pinpointed". Current Biology 13 (17).