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Hemimastigote
Hemimastigophora is a group of single-celled eukaryotic organisms with a single family, Spironemidae, first identified in 1988. 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 kingdoms. It is potentially 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 was unclear, but the authors suggested that the structure of its pellicle and cell nucleus indicated a close relationship with Euglenozoa. For 30 years after the description of the group, no genetic information was available. During that time, researchers proposed that it should be classified in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hemimastix
Spironemidae is a family of heterotrophic flagellates, in the group Hemimastigophora. They vary in size and shape from the ellipsoid ''Hemimastix amphikineta'' (14 × 7 μm) to the vermiform ''Spironema terricola'' (43 × 3 μm), and are united by the possession of two rows of cilia, called kineties. Phylogenomic analysis shows that Hemimastigophora are a distinct and ancient lineage of eukaryotic organisms, forming a possible sister clade to the supergroup Diaphoretickes. Taxonomy * Order Hemimastigida Foissner, Blatterer & Foissner 1988 [Hemimastigophora Foissner, Blatterer & Foissner 1988 sensu Cavalier-Smith 1993; Hemimastigea Foissner, Blatterer & Foissner 1988; Hemimastigidea] ** Family Spironematellidae *** Genus '' Hemimastix'' Foissner, Blatterer & Foissner, 1988 **** Species '' H. amphikineta'' Foissner, Blatterer & Foissner, 1988 **** Species '' H. kukwesjijk'' Eglit & Simpson, 2018 *** Genus ''Stereonema'' Foissner& Foissner, 1993 non ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tree Of Life (biology)
The tree of life or universal tree of life is a metaphor, model and research tool used to explore the evolution of life and describe the relationships between organisms, both living and extinct, as described in a famous passage in Charles Darwin's ''On the Origin of Species'' (1859). Tree diagrams originated in the medieval era to represent genealogical relationships. Phylogenetic tree diagrams in the evolutionary sense date back to the mid-nineteenth century. The term phylogeny for the evolutionary relationships of species through time was coined by Ernst Haeckel, who went further than Darwin in proposing phylogenic histories of life. In contemporary usage, ''tree of life'' refers to the compilation of comprehensive phylogenetic databases rooted at the last universal common ancestor of life on Earth. Two public databases for the tree of life are ''TimeTree'', for phylogeny and divergence times, and the ''Open Tree of Life'', for phylogeny. Early natural classifica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phylogenomics
Phylogenomics is the intersection of the fields of evolution and genomics. The term has been used in multiple ways to refer to analysis that involves genome data and evolutionary reconstructions. It is a group of techniques within the larger fields of phylogenetics and genomics. Phylogenomics draws information by comparing entire genomes, or at least large portions of genomes. Phylogenetics compares and analyzes the sequences of single genes, or a small number of genes, as well as many other types of data. Four major areas fall under phylogenomics: * Prediction of gene function * Establishment and clarification of evolutionary relationships * Gene family evolution * Prediction and retracing lateral gene transfer. The ultimate goal of phylogenomics is to reconstruct the evolutionary history of species through their genomes. This history is usually inferred from a series of genomes by using a genome evolution model and standard statistical inference methods (e.g. Bayesian inference ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spironema (flagellate)
Spironemidae is a family of heterotrophic flagellates, in the group Hemimastigophora. They vary in size and shape from the ellipsoid ''Hemimastix amphikineta'' (14 × 7 μm) to the vermiform ''Spironema terricola'' (43 × 3 μm), and are united by the possession of two rows of cilia, called kineties. Phylogenomic analysis shows that Hemimastigophora are a distinct and ancient lineage of eukaryotic organisms, forming a possible sister clade to the supergroup Diaphoretickes. Taxonomy * Order Hemimastigida Foissner, Blatterer & Foissner 1988 [Hemimastigophora Foissner, Blatterer & Foissner 1988 sensu Cavalier-Smith 1993; Hemimastigea Foissner, Blatterer & Foissner 1988; Hemimastigidea] ** Family Spironematellidae *** Genus '' Hemimastix'' Foissner, Blatterer & Foissner, 1988 **** Species '' H. amphikineta'' Foissner, Blatterer & Foissner, 1988 **** Species '' H. kukwesjijk'' Eglit & Simpson, 2018 *** Genus ''Stereonema'' Foissner& Foissner, 1993 non ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nova Scotia
Nova Scotia ( ; ; ) is one of the thirteen provinces and territories of Canada. It is one of the three Maritime provinces and one of the four Atlantic provinces. Nova Scotia is Latin for "New Scotland". Most of the population are native English-speakers, and the province's population is 969,383 according to the 2021 Census. It is the most populous of Canada's Atlantic provinces. It is the country's second-most densely populated province and second-smallest province by area, both after Prince Edward Island. Its area of includes Cape Breton Island and 3,800 other coastal islands. The Nova Scotia peninsula is connected to the rest of North America by the Isthmus of Chignecto, on which the province's land border with New Brunswick is located. The province borders the Bay of Fundy and Gulf of Maine to the west and the Atlantic Ocean to the south and east, and is separated from Prince Edward Island and the island of Newfoundland by the Northumberland and Cabot straits, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhizaria
The Rhizaria are an ill-defined but species-rich supergroup of mostly unicellular eukaryotes. Except for the Chlorarachniophytes and three species in the genus Paulinella in the phylum Cercozoa, they are all non-photosynthethic, but many foraminifera and radiolaria have a symbiotic relationship with unicellular algae. A multicellular form, ''Guttulinopsis vulgaris'', a cellular slime mold, has also been described. This group was used by Cavalier-Smith in 2002, although the term "Rhizaria" had been long used for clades within the currently recognized taxon. Being described mainly from rDNA sequences, they vary considerably in form, having no clear morphological distinctive characters (synapomorphies), but for the most part they are amoeboids with filose, reticulose, or microtubule-supported pseudopods. In the absence of an apomorphy, the group is ill-defined, and its composition has been very fluid. Some Rhizaria possess mineral exoskeleton (thecae or loricas), which is in differ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ancyromonadida
Ancyromonadida or Planomonadida is a small group of biflagellated protists found in the soil and in aquatic habitats, where they feed on bacteria.Cavalier-Smith, T. (2013)Early evolution of eukaryote feeding modes, cell structural diversity, and classification of the protozoan phyla Loukozoa, Sulcozoa, and Choanozoa European journal of protistology, 49(2), 115-178. Includes freshwater or marine organisms, benthic, dorsoventrally compressed and with two unequal flagellae, each emerging from a separate pocket. The apical anterior flagellum can be very thin or end in the cell membrane, while the posterior flagellum is long and is inserted ventrally or laterally. The cell membrane is supported by a thin single layer teak and the mitochondrial crests are discoidal / flat. The group's placement is doubtful, as it seems to fall outside the five supergroups of eukaryotes. Cavalier-Smith considers that they constitute a basal group to Amoebozoa and Opisthokonta and places it together w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apusozoa
The Apusozoa are an Obazoa phylum comprising several genera of flagellate eukaryotes. They are usually around 5–20 μm in size, and occur in soils and aquatic habitats, where they feed on bacteria. They are grouped together based on the presence of an organic shell or theca under the dorsal surface of the cell. The name derives from the Ancient Greek words for footless () and animal (). This phylum is currently defined as containing the Breviata and the Apusomonadida. However, it currently usually is viewed as paraphyletic, with the Breviata as more basal. The opisthokonts appear to have emerged as sister of the apusomonadida. It has been suggested that the Mantamonadida be classified in Apusozoa. The ancyromonadida appear to be Varisulca, Planomonadida, shifting them possibly more basal than the Amoebozoa, or less basal. While some classification systems have placed Hemimastigida in Apusozoa, 2018 research indicated that hemimastigotes (/Hemimastix/Spironemidae) are thei ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alveolate
The alveolates (meaning "pitted like a honeycomb") are a group of protists, considered a major clade and Biological classification, superphylum within Eukarya. They are currently grouped with the stramenopiles and Rhizaria among the protists with tubulocristate mitochondria, the group being referred to as SAR supergroup, SAR. Characteristics The most notable shared characteristic is the presence of cortical (near the surface) alveoli (sacs). These are flattened vesicle (biology), vesicles (sacs) arranged as a layer just under the cell membrane, membrane and supporting it, typically contributing to a flexible pellicle (thin skin). In armored dinoflagellates they may contain stiff plates. Alveolates have mitochondrion, 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 g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Euglenozoa
Euglenozoa are a large group of flagellate Discoba. They include a variety of common free-living species, as well as a few important parasites, some of which infect humans. Euglenozoa are represented by three major clades, i.e., Kinetoplastea, Diplonema and Symbiontida. Euglenozoa are unicellular, mostly around in size, although some euglenids get up to long. Structure Most euglenozoa have two flagella, which are inserted parallel to one another in an apical or subapical pocket. In some these are associated with a cytostome or mouth, used to ingest bacteria or other small organisms. This is supported by one of three sets of microtubules that arise from the flagellar bases; the other two support the dorsal and ventral surfaces of the cell. Some other euglenozoa feed through absorption, and many euglenids possess chloroplasts, the only eukaryotes outside Diaphoretickes to do so without performing kleptoplasty, and so obtain energy through photosynthesis. These chloroplasts are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cell Nucleus
The cell nucleus (pl. nuclei; from Latin or , meaning ''kernel'' or ''seed'') is a membrane-bound organelle found in eukaryotic cells. Eukaryotic cells usually have a single nucleus, but a few cell types, such as mammalian red blood cells, have no nuclei, and a few others including osteoclasts have many. The main structures making up the nucleus are the nuclear envelope, a double membrane that encloses the entire organelle and isolates its contents from the cellular cytoplasm; and the nuclear matrix, a network within the nucleus that adds mechanical support. The cell nucleus contains nearly all of the cell's genome. Nuclear DNA is often organized into multiple chromosomes – long stands of DNA dotted with various proteins, such as histones, that protect and organize the DNA. The genes within these chromosomes are structured in such a way to promote cell function. The nucleus maintains the integrity of genes and controls the activities of the cell by regulating gene expres ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pellicle (biology)
Protozoa (singular: protozoan or protozoon; alternative plural: protozoans) are a group of Unicellular organism, single-celled eukaryotes, either free-living or Parasitism, parasitic, that feed on organic matter such as other microorganisms or organic tissues and debris. Historically, protozoans were regarded as "one-celled animals", because they often possess animal-like behaviours, such as motility and predation, and lack a cell wall, as found in plants and many algae. When first introduced by Georg August Goldfuss, Georg Goldfuss (originally German orthography, spelled Goldfuß) in 1818, the taxon Protozoa was erected as a Class (biology), class within the Animalia, with the word 'protozoa' meaning "first animals". In later classification schemes it was elevated to a variety of higher ranks, including Phylum (biology), phylum, Subkingdom (biology), subkingdom and Kingdom (biology), kingdom, and sometimes included within Protoctista or Protista. The approach of classifying Prot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
