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Eukaryotic
The eukaryotes ( ) constitute the Domain (biology), domain of Eukaryota or Eukarya, organisms whose Cell (biology), cells have a membrane-bound cell nucleus, nucleus. All animals, plants, Fungus, fungi, seaweeds, and many unicellular organisms are eukaryotes. They constitute a major group of Outline of life forms, life forms alongside the two groups of prokaryotes: the Bacteria and the Archaea. Eukaryotes represent a small minority of the number of organisms, but given their generally much larger size, their collective global biomass is much larger than that of prokaryotes. The eukaryotes emerged within the archaeal Kingdom (biology), kingdom Asgard (Archaea), Promethearchaeati and its sole phylum Promethearchaeota. This implies that there are only Two-domain system, two domains of life, Bacteria and Archaea, with eukaryotes incorporated among the Archaea. Eukaryotes first emerged during the Paleoproterozoic, likely as Flagellated cell, flagellated cells. The leading evolutiona ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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] |
SAR Supergroup
SAR is a highly diverse clade of eukaryotes, often considered a supergroup, that includes stramenopiles (heterokonts), alveolates, and rhizarians. It is a node-based taxon (under the Sar name), including all descendants of the three groups' last common ancestor, and comprises most of the now-rejected Chromalveolata. Their sister group has been found to be telonemids, with which they make up the TSAR clade. Harosa is sometimes used synonymously with TSAR. Etymology The name SAR is an acronym derived from the first letters of its three constituent clades; it has been alternatively spelled RAS. The term Harosa (at the subkingdom level) has also been used, with Stramenopiles replaced by its synonym Heterokonta in this variant of the acronym. History of discovery Before the discovery of the SAR supergroup, stramenopiles and alveolates were classified in the supergroup Chromalveolata alongside haptophytes and cryptomonads, being believed to have acquired plastids th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diaphoretickes
Diaphoretickes is a major group of eukaryote, eukaryotic organisms spanning over 400,000 species. The majority of the earth's biomass that carries out photosynthesis belongs to Diaphoretickes. In older classification systems, members of the Diaphoretickes were variously placed in the Kingdom (biology), kingdoms Protozoa or Protist, Protista. Etymology The name Diaphoretickes derives (''diaforetikés'') meaning diverse, dissimilar, referring to the wide morphology (biology), morphological and cellular diversity among members of this clade. History Eukaryotes, organisms whose cells contain a cell nucleus, nucleus, have been traditionally grouped into four kingdom (biology), kingdoms: animals, plants, fungi and protists. In the late 20th century, molecular phylogenetic analyses revealed that protists are a paraphyletic assortment of many independent evolutionary lineages or clades, from which animals, fungi and plants evolved. However, the relationships between these clades re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fungi
A fungus (: fungi , , , or ; or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and mold (fungus), molds, as well as the more familiar mushrooms. These organisms are classified as one of the kingdom (biology)#Six kingdoms (1998), traditional eukaryotic kingdoms, along with Animalia, Plantae, and either Protista or Protozoa and Chromista. A characteristic that places fungi in a different kingdom from plants, bacteria, and some protists is chitin in their cell walls. Fungi, like animals, are heterotrophs; they acquire their food by absorbing dissolved molecules, typically by secreting digestive enzymes into their environment. Fungi do not photosynthesize. Growth is their means of motility, mobility, except for spores (a few of which are flagellated), which may travel through the air or water. Fungi are the principal decomposers in ecological systems. These and other differences place fungi in a single group of related o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Discoba
Excavata is an obsolete, extensive and diverse Paraphyly, paraphyletic group of unicellular Eukaryote, Eukaryota. The group was first suggested by Simpson and Patterson in 1999 and the name latinized and assigned a rank by Thomas Cavalier-Smith in 2002. It contains a variety of free-living and symbiotic protists, and includes some important parasites of humans such as ''Giardia'' and ''Trichomonas''. Excavates were formerly considered to be included in the now- obsolete Protist, Protista kingdom. They were distinguished from other lineages based on electron-microscopic information about how the cells are arranged (they have a distinctive ultrastructural identity). They are considered to be a Basal_(phylogenetics), basal flagellate lineage. On the basis of phylogenomic analyses, the group was shown to contain three widely separated eukaryote groups, the discobids, metamonads, and malawimonads. A current view of the composition of the excavates is given below, indicating that th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telonemia
Telonemia is a phylum of microscopic eukaryotes commonly known as telonemids. They are unicellular free-living flagellates with a unique combination of Cell (biology), cell structures, including a highly complex cytoskeleton unseen in other eukaryotes. Telonemia shares several distinctive features with its related group, the SAR supergroup, SAR Supergroup (biology), supergroup. Among these features are cortical alveoli, small sacs beneath the cell's surface that act as cushions, providing support and helping to maintain the cell's shape. Additionally, they possess tripartite mastigonemes, complex three-part hair-like structures on their flagella, the whip-like tails used for movement. These structures enhance their swimming capabilities by increasing resistance against water. Furthermore, Telonemia is equipped with filopodia, very thin, thread-like projections extending from the cell body. These projections can serve various purposes, such as aiding in movement or capturing foo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archaeplastida
The Archaeplastida (or kingdom Plantae '' sensu lato'' "in a broad sense"; pronounced ) are a major group of eukaryotes, comprising the photoautotrophic red algae (Rhodophyta), green algae, land plants, and the minor group glaucophytes. It also includes the non-photosynthetic lineage Rhodelphidia, a predatorial (eukaryotrophic) flagellate that is sister to the Rhodophyta, and probably the microscopic picozoans. The Archaeplastida have chloroplasts that are surrounded by two membranes, suggesting that they were acquired directly through a single endosymbiosis event by phagocytosis of a cyanobacterium. All other groups which have chloroplasts, besides the amoeboid genus '' Paulinella'', have chloroplasts surrounded by three or four membranes, suggesting they were acquired secondarily from red or green algae. Unlike red and green algae, glaucophytes have never been involved in secondary endosymbiosis events. The cells of the Archaeplastida typically lack centrioles and have mit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hemimastigophora
Hemimastigophora is a group of unicellular, single-celled eukaryotic organisms including the Spironematellidae, first identified in 1988, and the Paramastigidae. Over the next 30 years, different authors proposed placing these organisms in various branches of the eukaryotes. In 2018 Lax ''et al''. reported the first genetic information for Spironemidae, and suggest that they are from an ancient lineage of eukaryotes which constitute a separate clade from all other eukaryotic kingdom (biology), kingdoms. It may be related to the Telonemia. History of classification Hemimastigophora was established in 1988 by Foissner ''et al''., as a new phylum with a single family, Spironemidae. Its placement on the eukaryote Tree of life (biology), tree of life was unclear, but the authors suggested that the structure of its Pellicle (biology), pellicle and cell nucleus indicated a close relationship with Euglenozoa. For 30 years after the description of the group, no genetic informati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lynn Margulis
Lynn Margulis (born Lynn Petra Alexander; March 5, 1938 – November 22, 2011) was an American evolutionary biologist, and was the primary modern proponent for the significance of symbiogenesis, symbiosis in evolution. In particular, Margulis transformed and fundamentally framed current understanding of the evolution of Eukaryote, cells with nuclei by proposing it to have been the result of symbiotic mergers of bacteria. Margulis was also the co-developer of the Gaia hypothesis with the British chemist James Lovelock, proposing that the Earth functions as a single self-regulating system, and was the principal defender and promulgator of the Five kingdoms, five kingdom classification of Robert Whittaker (ecologist), Robert Whittaker. Throughout her career, Margulis' work could arouse intense objections, and her formative paper, "On the Origin of Mitosing Cells", appeared in 1967 after being rejected by about fifteen journals. Still a junior faculty member at Boston University at t ... [...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] |
Alveolate
The alveolates (meaning "pitted like a honeycomb") are a group of protists, considered a major unranked clade or superphylum within Eukaryota. They are currently grouped with the Stramenopiles and Rhizaria among the protists with tubulocristate mitochondria into the SAR supergroup. Characteristics The most notable shared characteristic is the presence of cortical (near the surface) alveoli (sacs). These are flattened vesicles (sacs) arranged as a layer just under the membrane and supporting it, typically contributing to a flexible pellicle (thin skin). In armored dinoflagellates they may contain stiff plates. Alveolates have mitochondria with tubular cristae ( invaginations), and cells often have pore-like intrusions through the cell surface. The group contains free-living and parasitic organisms, predatory flagellates, and photosynthetic organisms. Almost all sequenced mitochondrial genomes of ciliates and apicomplexa are linear. The mitochondria almost all carry mtDN ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
