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Biddulphiophycidae
Biddulphiophycidae or Biddulphiineae is a grouping of Centrales. In some taxonomic schemes Centrales or Centric diatoms are named Coscinodiscophyceae and may have different naming of suborders and families. Description Valves A valve is a device or natural object that regulates, directs or controls the flow of a fluid (gases, liquids, fluidized solids, or slurries) by opening, closing, or partially obstructing various passageways. Valves are technically fittings ... primarily bipolar. They do not have a marginal ring of processes. See also * Coscinodiscineae References Coscinodiscophyceae SAR supergroup suborders {{Diatom-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coscinodiscophyceae
The Coscinodiscophyceae are a class of diatoms. They are similar to the Centrales, a traditional, paraphyletic subdivision of the heterokont algae known as diatoms. The order is named for the shape of the cell walls (or valves or frustules) of centric diatoms, which are circular or ellipsoid in valve view. The valves often bear radially symmetrical ornamental patterns that can appear as dots when viewed with an optical microscope. Some also bear spines on their valves, which may either increase cell surface area and reduce sinking, or act as a deterrent to zooplankton grazers. Unlike pennate diatoms, centric diatoms never have a raphe. In terms of cell cycle, vegetative cells are diploid and undergo mitosis during normal cell division. In sexual species, oogamous meiosis produces haploid gametes, either ova or sperm cells. These fuse to produce a zygote which expands in size to develop into an auxospore from which full-sized vegetative cells are produced. In some taxonom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Centrales
The Coscinodiscophyceae are a class of diatoms. They are similar to the Centrales, a traditional, paraphyletic subdivision of the heterokont algae known as diatoms. The order is named for the shape of the cell walls (or valves or frustules) of centric diatoms, which are circular or ellipsoid in valve view. The valves often bear radially symmetrical ornamental patterns that can appear as dots when viewed with an optical microscope. Some also bear spines on their valves, which may either increase cell surface area and reduce sinking, or act as a deterrent to zooplankton grazers. Unlike pennate diatoms, centric diatoms never have a raphe. In terms of cell cycle, vegetative cells are diploid and undergo mitosis during normal cell division. In sexual species, oogamous meiosis produces haploid gametes, either ova or sperm cells. These fuse to produce a zygote which expands in size to develop into an auxospore from which full-sized vegetative cells are produced. In some ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eupodiscaceae
Eupodiscaceae is a diatom family (Bacillariophyceae) present both in marine and freshwater habitatsTomas, C. R., Hasle G. R., Syvertsen, E. E., Steidinger, K. A., Tangen, K., Throndsen, J., Heimdal, B. R., (1997). ''Identifying Marine Phytoplankton'',pp. 858. Academic Press.Simonsen, R., (1979). ''The diatom system: Ideas on phylogeny'', ''Bacillaria'' 2:9-71. ''Odontella'' is the only genera in this family with typical marine species. However, Round et al. (1990) placed ''Odontella'' in Triceratiaceae (Schutt) Lemmermann, order Triceratiales Round and Crawford, subclass Biddulphiophycidae Biddulphiophycidae or Biddulphiineae is a grouping of Centrales. In some taxonomic schemes Centrales or Centric diatoms are named Coscinodiscophyceae and may have different naming of suborders and families. Description Valves A valve is a ... Round and Crawford.Round, F. E., Crawford, R. M., Mann, D. G., (1990). ''The Diatoms, Biology and Morphology of the Genera'', pp. 747. Cambr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eukaryote
Eukaryotes () are organisms whose cells have a nucleus. All animals, plants, fungi, and many unicellular organisms, are Eukaryotes. They belong to the group of organisms Eukaryota or Eukarya, which is one of the three domains of life. Bacteria and Archaea (both prokaryotes) make up the other two domains. The eukaryotes are usually now regarded as having emerged in the Archaea or as a sister of the Asgard archaea. This implies that there are only two domains of life, Bacteria and Archaea, with eukaryotes incorporated among archaea. Eukaryotes represent a small minority of the number of organisms, but, due to their generally much larger size, their collective global biomass is estimated to be about equal to that of prokaryotes. Eukaryotes emerged approximately 2.3–1.8 billion years ago, during the Proterozoic eon, likely as flagellated phagotrophs. Their name comes from the Greek εὖ (''eu'', "well" or "good") and κάρυον (''karyon'', "nut" or "kernel"). Euka ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SAR Supergroup
The SAR supergroup, also just SAR or Harosa, is a clade that includes stramenopiles (heterokonts), alveolates, and Rhizaria. The name is an acronym derived from the first letters of each of these clades; it has been alternatively spelled "RAS". The term "Harosa" (at the subkingdom level) has also been used. The SAR supergroup is a node-based taxon. Note that as a formal taxon, "Sar" has only its first letter capitalized, while the earlier abbreviation, SAR, retains all uppercase letters. Both names refer to the same group of organisms, unless further taxonomic revisions deem otherwise. Members of the SAR supergroup were once included under the separate supergroups Chromalveolata (Chromista and Alveolata) and Rhizaria, until phylogenetic studies confirmed that stramenopiles and alveolates diverged with Rhizaria. This apparently excluded haptophytes and cryptomonads, leading Okamoto ''et al.'' (2009) to propose the clade Hacrobia to accommodate them. Phylogeny Based on a compi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heterokonta
Heterokonts are a group of protists (formally referred to as Heterokonta, Heterokontae or Heterokontophyta). The group is a major line of eukaryotes. Most are algae, ranging from the giant multicellular kelp to the unicellular diatoms, which are a primary component of plankton. Other notable members of the Stramenopiles include the (generally) parasitic oomycetes, including ''Phytophthora'', which caused the Great Famine of Ireland, and ''Pythium'', which causes seed rot and damping off. The name "heterokont" refers to the type of motile life cycle stage, in which the flagellated cells possess two differently arranged flagella (see zoospore). History In 1899, Alexander Luther created the term "Heterokontae" for some algae with unequal flagella, today called Xanthophyceae. Later, some authors (e.g., Copeland, 1956) included other groups in Heterokonta, expanding the name's sense. The term continues to be applied in different ways, leading to Heterokontophyta being applied al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hemiaulaceae
Hemiaulaceae is a diatom A diatom (Neo-Latin ''diatoma''), "a cutting through, a severance", from el, διάτομος, diátomos, "cut in half, divided equally" from el, διατέμνω, diatémno, "to cut in twain". is any member of a large group comprising sev ... family. Species live between -1.86 and 29.47 degrees Celsius and at depths of up to 2010 meters. See also * Coscinodiscineae References Coscinodiscophyceae Diatom families {{Diatom-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chaetocerotaceae
Chaetocerotaceae is a diatom family ( Bacillariophyta). This family comprise the three genera ''Attheya'' T. West, '' Bacteriastrum'' Shadbolt and ''Chaetoceros'' Ehrenberg. ''Chaetoceros'' is perhaps the largest and most species rich genus of marine planktonic diatoms. The taxonomic status within Chaetocerotaceae at present is somewhat unclear. Description The cells have valves with long setae. Cells are often in unseparable chains, but may appear as solitary cells in some species. Chains are formed by fusion of silica between the setae. Endogenous resting spores A resting spore is a resistant cell, used to survive adverse environmental conditions. Resting spore is a term commonly applied to both diatoms and fungi. In fungi A resting spore can be a spore created by fungi which is thickly encysted (has a t ... are common and very different from normal vegetative cells. References {{Taxonbar, from=Q2947532 Coscinodiscophyceae Diatom families ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Valve (mollusc)
A valve is each articulating part of the shell of a mollusc or another multi-shelled animal such as brachiopods and some crustaceans. Each part is known as a valve or in the case of chitons, a "plate". Members of two classes of molluscs, the Bivalvia (clams) and the Polyplacophora (chitons), have valves. Species within one family of very unusual small sea snails, marine opisthobranch gastropods in the family Juliidae, also have two articulating shells or valves, which resemble those of a bivalve. This exceptional family is commonly known as the bivalved gastropods. Gastropods in general are sometimes called "univalves", because in those that have a shell, the shell is usually in one part. Chitons The valves of chitons are eight dorsal, articulated shell plates, which are frequently coloured and sculpted. After death the girdle that holds the plates together disintegrates and the plates separate. Thus individual plates can be found washed up in beach drift, as shown in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Process (anatomy)
In anatomy, a process ( la, processus) is a projection or outgrowth of tissue from a larger body. For instance, in a vertebra, a process may serve for muscle attachment and leverage (as in the case of the transverse and spinous processes), or to fit (forming a synovial joint), with another vertebra (as in the case of the articular processes).Moore, Keith L. et al. (2010) ''Clinically Oriented Anatomy'', 6th Ed, p.442 fig. 4.2 The word is used even at the microanatomic level, where cells can have processes such as cilia or pedicels. Depending on the tissue, processes may also be called by other terms, such as ''apophysis'', ''tubercle'', or ''protuberance''. Examples Examples of processes include: *The many processes of the human skull: ** The mastoid and styloid processes of the temporal bone ** The zygomatic process of the temporal bone ** The zygomatic process of the frontal bone ** The orbital, temporal, lateral, frontal, and maxillary processes of the zygomatic bone ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
