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Amoebozoa
Amoebozoa is a major Taxonomy (biology), taxonomic group containing about 2,400 described species of Amoeba, amoeboid protists, often possessing blunt, fingerlike, Pseudopod#Morphology, lobose pseudopods and tubular mitochondrial cristae. In traditional classification schemes, Amoebozoa is usually ranked as a phylum within either the kingdom (biology), kingdom Protista or the kingdom Protozoa. In the classification favored by the International Society of Protistologists, it is retained as an unranked "supergroup (biology), supergroup" within Eukaryota. Molecular genetics, Molecular genetic analysis supports Amoebozoa as a monophyletic clade. Modern studies of eukaryotic phylogenetic trees identify it as the sister group to Opisthokonta, another major clade which contains both fungi and animals as well as several other clades comprising some 300 species of unicellular eukaryotes. Amoebozoa and Opisthokonta are sometimes grouped together in a high-level taxon, named Amorphea. Amoeboz ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protista
A protist ( ) or protoctist is any Eukaryote, eukaryotic organism that is not an animal, Embryophyte, land plant, or fungus. Protists do not form a Clade, natural group, or clade, but are a Paraphyly, paraphyletic grouping of all descendants of the last eukaryotic common ancestor excluding land plants, animals, and fungi. Protists were historically regarded as a separate taxonomic rank, taxonomic kingdom (biology), kingdom known as Protista or Protoctista. With the advent of phylogenetic analysis and electron microscopy studies, the use of Protista as a formal taxon was gradually abandoned. In modern classifications, protists are spread across several eukaryotic clades called supergroup (biology), supergroups, such as Archaeplastida (photoautotrophs that includes land plants), SAR supergroup, SAR, Obazoa (which includes fungi and animals), Amoebozoa and "Excavata". Protists represent an extremely large genetic diversity, genetic and ecological diversity in all environments, in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protist
A protist ( ) or protoctist is any eukaryotic organism that is not an animal, land plant, or fungus. Protists do not form a natural group, or clade, but are a paraphyletic grouping of all descendants of the last eukaryotic common ancestor excluding land plants, animals, and fungi. Protists were historically regarded as a separate taxonomic kingdom known as Protista or Protoctista. With the advent of phylogenetic analysis and electron microscopy studies, the use of Protista as a formal taxon was gradually abandoned. In modern classifications, protists are spread across several eukaryotic clades called supergroups, such as Archaeplastida ( photoautotrophs that includes land plants), SAR, Obazoa (which includes fungi and animals), Amoebozoa and " Excavata". Protists represent an extremely large genetic and ecological diversity in all environments, including extreme habitats. Their diversity, larger than for all other eukaryotes, has only been discovered in rece ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eumycetozoa
Eumycetozoa (), or true slime molds, is a diverse group of protists that behave as slime molds and develop fruiting bodies, either as sorocarps or as sporocarp (fungi), sporocarps. It is a monophyletic group or clade within the phylum Amoebozoa that contains the Myxogastria, myxogastrids, dictyostelids and Protosporangiida, protosporangiids. Characteristics Eumycetozoa is a clade that includes three groups of amoebozoan protists: Myxogastria, Dictyostelia and Protosporangiida—also known as Myxomycetes, Dictyosteliomycetes and Ceratiomyxomycetes, respectively. It is defined on a Phylogenetic nomenclature#Phylogenetic definitions of clade names, node-based approach as the least inclusive clade containing the species ''Dictyostelium discoideum'' (a dictyostelid), ''Physarum polycephalum'' (a myxogastrid) and ''Ceratiomyxa fruticulosa'' (a protosporangiid). All known members of Eumycetozoa generate fruiting bodies, either as sorocarps (in dictyostelids) or as sporocarp (fungi), s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cutosea
Cutosea () is a small group of marine amoeboid protists proposed in 2016. It is a monotypic class of Amoebozoa containing the order Squamocutida (). Cutosean organisms are characterized by a cell coat of microscales separated from the cell membrane. Four genera, '' Armaparvus'', '' Idionectes'', '' Sapocribrum'' and '' Squamamoeba'', belong to this group, distributed in three families. Characteristics The cells of cutosean amoebae are surrounded by a continuous thin, somewhat flexible envelope, unique in structure because it is not attached to the cytoplasmic membrane. Below this envelope, they present oval microscales surrounded by a dense matrix. The small scales are not visible under a light microscope. The envelope is penetrated by one or many small pores, which allow subpseudopodia to occasionally protrude from the cell membrane, for a very slow locomotion. Locomoting cells are flattened, oval or round in shape. All of their cells lack cilia or centrosomes, except for the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amoeba
An amoeba (; less commonly spelled ameba or amœba; : amoebas (less commonly, amebas) or amoebae (amebae) ), often called an amoeboid, is a type of Cell (biology), cell or unicellular organism with the ability to alter its shape, primarily by extending and retracting pseudopodia, pseudopods. Amoebae do not form a single Taxonomy (biology), taxonomic group; instead, they are found in every major Lineage (evolution), lineage of eukaryote, eukaryotic organisms. Amoeboid cells occur not only among the protozoa, but also in fungi, algae, and animals. Microbiologists often use the terms "amoeboid" and "amoeba" interchangeably for any organism that exhibits amoeboid movement. In older classification systems, most amoebae were placed in the Class (biology), class or subphylum Sarcodina, a grouping of Unicellular organism, single-celled organisms that possess pseudopods or move by protoplasmic flow. However, molecular phylogenetic studies have shown that Sarcodina is not a monophyletic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amorphea
Amorphea is a taxonomic supergroup that includes the basal Amoebozoa and Obazoa. That latter contains the Opisthokonta, which includes the fungi, animals and the choanoflagellates. The taxonomic affinities of the members of this clade were originally described and proposed by Thomas Cavalier-Smith in 2002. The International Society of Protistologists, the recognised body for taxonomy of protozoa, recommended in 2012 that the term Unikont be changed to Amorphea because the name "Unikont" is based on a hypothesized synapomorphy that the ISOP authors and other scientists later rejected. It includes amoebozoa, opisthokonts, and apusomonads. Taxonomic revisions within this group Thomas Cavalier-Smith proposed two new phyla: Sulcozoa, which consists of the subphyla Apusozoa ( Apusomonadida and Breviatea), and Varisulca, which includes the subphyla Diphyllatea, Discocelida, Mantamonadidae, Planomonadida and Rigifilida. Further work by Cavalier-Smith showed that Sul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Evosea
Evosea is a diverse clade of amoeboid protists discovered through molecular analyses. Along with Tubulinea and Discosea, Evosea is one of the three major groups within Amoebozoa, an important clade of eukaryotic organisms. It contains unicellular organisms that display a wide variety of life cycles and cell shapes, including amoebae, flagellates and different kinds of slime molds. Characteristics Evosea is a strongly supported clade of eukaryotes containing four large groups of amoebozoans: Eumycetozoa or "true" slime molds, Variosea, Cutosea and Archamoebae. It is defined on a node-based approach as the least-inclusive clade containing '' Dictyostelium discoideum'' (a true slime mold), '' Protostelium nocturnum'' (a variosean), '' Squamamoeba japonica'' (a cutosean), and '' Entamoeba histolytica'' (an archamoeba). Within Evosea, organisms can vary across almost the entire range of morphologies seen in Amoebozoa. Many members have complex life cycles that include ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Conosa
Conosa is a grouping of Amoebozoa. It is subdivided into three groups: Archamoeba, Variosea and Mycetozoa. In some classifications, the mycetozoan Myxogastria and Dictyostelia are united in Macromycetozoa (= Eumycetozoa). Conosa includes the species '' Dictyostelium discoideum,'' a social amoeba, and '' Entamoeba histolytica'', a human pathogen, among others. Conosa are morphologically defined by a conical microtubular structure, and have been found to be monophyletic. Characteristics The Conosa group was first proposed by Thomas Cavalier-Smith in 1998 as a subphylum of Amoebozoa. Cavalier-Smith originally separated this group into two infraphyla: Archamoebae and Mycetozoa. Notable characteristics of these two groups are that Mycetozoa are free living, while Archamoebae are amitochondrial. This clade is morphologically defined by their complex microtubular skeleton that forms a partial or complete cone. They have a monolayer of microtubules that surround at least some ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Discosea
Discosea is a class of Amoebozoa, consisting of naked amoebae with a flattened, discoid body shape. Members of the group do not produce tubular or subcylindrical pseudopodia, like amoebae of the class Tubulinea. When a discosean is in motion, a transparent layer called ''hyaloplasm'' forms at the leading edge of the cell (see lamellipodium). In some discoseans, short "subpseudopodia" may be extended from this hyaloplasm, but the granular contents of the cell do not flow into these, as in true pseudopodia. Discosean amoebae lack hard shells, but some, like ''Cochliopodium'' and '' Korotnevella'' secrete intricate organic scales which may cover the upper (dorsal) surface of the cell. No species have flagella or flagellated stages of life. The composition of Discosea is similar to that of the class Flabellinea, proposed by Alexey Smirnov and his collaborators in 2005. However, Discosea is a more comprehensive taxon, including several groups not included in Flabellinea. In 2011, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tubulinea
The Tubulinea are a major grouping of Amoebozoa, including most of the more familiar amoebae genera like ''Amoeba'', '' Arcella'', '' Difflugia'' and '' Hartmannella''. Characteristics During locomotion most Tubulinea have a roughly cylindrical form or produce numerous cylindrical pseudopods. Each cylinder advances by a single central stream of cytoplasm, granular in appearance, and has no subpseudopodia. This distinguishes them from other amoeboid groups, although in some members this is not the normal type of locomotion. Classification This class was anticipated by some biologists such as Jahn, who grouped all amoebae with granular pseudopodia together, but most split the lobose amoebae into testate Testacealobosia and naked Gymnamoebia. These latter are polyphyletic, but molecular trees by Bolivar ''et al.'' identified a core monophyletic subgroup. Subsequent studies showed the testate lobose amoebae belong to the same group, which was thus renamed Lobosea ''sensu stric ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archamoebea
The Archamoebae are a group of protists originally thought to have evolved before the acquisition of mitochondria by eukaryotes. They include genera that are internal parasites or commensals of animals ('' Entamoeba'' and '' Endolimax''). A few species are human pathogens, causing diseases such as amoebic dysentery. The other genera of archamoebae live in freshwater habitats and are unusual among amoebae in possessing flagella. Most have a single nucleus and flagellum, but the giant amoeba '' Pelomyxa'' has many of each. Description Archamoebae are a diverse group of amoebae. Many have flagella for motility, while others do not. They grow in the absence of oxygen, though some can tolerate small amounts. Most described species of Archamoebae either lack mitochondria or are described to have reduced mitosomes. Habitat They thrive and live in soil, freshwater, and marine habitats. History The group Archamoebae was proposed by Thomas Cavalier-Smith in 1998 as part of the Arche ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
