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Chaetognatha
The Chaetognatha or chaetognaths (meaning ''bristle-jaws'') are a phylum of predatory marine worms that are a major component of plankton worldwide. Commonly known as arrow worms, about 20% of the known Chaetognatha species are benthic, and can attach to algae and rocks. They are found in all marine waters, from surface tropical waters and shallow tide pools to the deep sea and polar regions. Most chaetognaths are transparent and are torpedo shaped, but some deep-sea species are orange. They range in size from . There are more than 120 modern species assigned to over 20 genera. Despite the limited diversity of species, the number of individuals is large. Arrow worms are usually considered a type of protostome that do not belong to either Ecdysozoa or Lophotrochozoa. Anatomy Chaetognaths are transparent or translucent dart-shaped animals covered by a cuticle. The body is divided into a distinct head, trunk, and tail. There are between four and fourteen hooked, grasping spines ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aphragmophora
Aphragmophora is an order of sagittodieans in the phylum Chaetognatha. Families * Bathybelidae Bieri, 1989Bieri, R. (1989). Krohnittellidae and Bathybelidae, new families in the phylum Chaetognatha; the rejection of the family Tokiokaispadellidae and the genera ''Tokiokaisapadella'', ''Zahonya'', and ''Aberrospadella''. ''Proceedings of the Biological Society of Washington'', 102(4), 973–976. * Krohnittidae Tokioka, 1965 * Pterokrohniidae Bieri, 1991Bieri, R. (1991). Systematics of the Chaetognatha. In Bone, Q., Kapp, H. & Pierrot-Bults, A. (Eds.), ''The Biology of Chaetognaths''. Oxford: Oxford University. * Pterosagittidae Tokioka, 1965 * Sagittidae Claus & Grobben, 1905Claus, C. & Grobben, K. (1905). ''Lehrbuch der Zoologie''. 7th edition. Marburg-Heßen: NG Elwertsche Verlagsbuchhandlung. See also *Taxonomy of invertebrates (Brusca & Brusca, 2003) The biological systematics and taxonomy of invertebrates as proposed by Richard C. Brusca and Gary J. Brusca in 2003 is a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phragmophora
Phragmophora is an order of sagittoideans in the phylum Chaetognatha. Families *Eukrohniidae Tokioka, 1965 *Heterokrohniidae Casanova, 1985Casanova, J. (1985). Description de l'appareil génital primitif du genre ''Heterokrohnia'' et nouvelle classification des Chaetognathes. ''Comptes Rendus Hebdomadaires des Séances de l'Académie des Sciences de Paris'', 301(8), 397–402. *Krohnittellidae Bieri, 1989Bieri, R. (1989). Krohnittellidae and Bathybelidae, new families in the phylum Chaetognatha; the rejection of the family Tokiokaispadellidae and the genera ''Tokiokaisapadella'', ''Zahonya'', and ''Aberrospadella''. ''Proceedings of the Biological Society of Washington'', 102(4), 973–976. *Spadellidae Tokioka, 1965 See also *Taxonomy of invertebrates (Brusca & Brusca, 2003) The biological systematics and taxonomy of invertebrates as proposed by Richard C. Brusca and Gary J. Brusca in 2003 is a system of classification of invertebrates, as a way to classify animals without ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caecosagitta Macrocephala
''Caecosagitta macrocephala'' is a deep sea marine chaetognath that is distributed in meso- and bathypelagic layers. It has a very wide distribution that ranges from the Subantarctic to Subarctic Ocean. Miyamoto, H., Machida, R. & Nishida, S. (2010). Genetic diversity and cryptic speciation of the deep-sea chaetognath ''Caecosagitta macrocephala'' (Fowler, 1904). ''Deep-Sea Research Part II: Topical Studies in Oceanography'', 57(24–26), 2211--2219. Cecosagitta macrocephalas have large heads, hence their name “macro-cephala”. Within their eyes are photoreceptive regions that allow them to catch weak light at bathypelagic depths. Along with their eyes, their gut or intestine has orange pigmentation and a luminous organ that gleams due to bioluminescence unlike some other species of Sagittidae.Thuesen, E. V., Goetz, F. E. & Haddock, S. H. (2010). Bioluminescent organs of two deep-sea arrow-worms, ''Eukrohnia fowleri'' and ''Caecosagitta macrocephala'', with further observations ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tetrodotoxin
Tetrodotoxin (TTX) is a potent neurotoxin. Its name derives from Tetraodontiformes, an order that includes pufferfish, porcupinefish, ocean sunfish, and triggerfish; several of these species carry the toxin. Although tetrodotoxin was discovered in these fish and found in several other animals (e.g., in blue-ringed octopuses, rough-skinned newts, and moon snails), it is actually produced by certain infecting or symbiotic bacteria like ''Pseudoalteromonas'', ''Pseudomonas'', and ''Vibrio'' as well as other species found in animals. Tetrodotoxin is a sodium channel blocker. It inhibits the firing of action potentials in neurons by binding to the voltage-gated sodium channels in nerve cell membranes and blocking the passage of sodium ions (responsible for the rising phase of an action potential) into the neuron. This prevents the nervous system from carrying messages and thus muscles from contracting in response to nervous stimulation. Its mechanism of action, selective blocking o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eukrohnia Fowleri
''Eukrohnia fowleri'' is a deep-sea marine arrow worm. It is the only known bioluminescent member of the genus ''Eukrohnia'', and one of the two known species of bioluminescent arrow worms, the other being the distantly related ''Caecosagitta macrocephala''. The bioluminescent organ of ''Eukrohnia fowleri'' is found along the center of its tail fin on both its dorsal and ventral side. It has a secreted bioluminescence that is thought to be coelenterazine Coelenterazine is a luciferin, a molecule that emits light after reaction with oxygen, found in many aquatic organisms across eight phyla. It is the substrate of many luciferases such as ''Renilla reniformis'' luciferase (Rluc), ''Gaussia'' lucif ... based. While both species use luciferases in conjunction with coelenterazine for light emission, the luciferase of ''Eukrohnia fowleri'' is highly stable after 30 minutes while the luciferase of ''Caecosagitta macrocephala'' becomes inactive. So far, there is no other bioluminescent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bioluminescent
Bioluminescence is the production and emission of light by living organisms. It is a form of chemiluminescence. Bioluminescence occurs widely in marine vertebrates and invertebrates, as well as in some Fungus, fungi, microorganisms including some bioluminescent bacteria, and terrestrial arthropods such as Firefly, fireflies. In some animals, the light is bacteriogenic, produced by symbiosis, symbiotic bacteria such as those from the genus ''Vibrio''; in others, it is autogenic, produced by the animals themselves. In a general sense, the principal chemical reaction in bioluminescence involves a light-emitting molecule and an enzyme, generally called luciferin and luciferase, respectively. Because these are generic names, luciferins and luciferases are often distinguished by the species or group, e.g. firefly luciferin. In all characterized cases, the enzyme Catalysis, catalyzes the Redox, oxidation of the luciferin. In some species, the luciferase requires other Cofactor (bio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lophotrochozoa
Lophotrochozoa (, "crest/wheel animals") is a clade of protostome animals within the Spiralia. The taxon was established as a monophyletic group based on molecular evidence. The clade includes animals like annelids, molluscs, bryozoans, brachiopods, and platyhelminthes. Groups Lophotrochozoa was defined in 1995 as the "last common ancestor of the three traditional lophophorate taxa (brachiopods, bryozoans, and phoronid worms), the mollusks and the annelids, and all of the descendants of that common ancestor". It is a cladistic definition (a node-based name), so the affiliation to Lophotrochozoa of spiralian groups not mentioned directly in the definition depends on the topology of the spiralian tree of life, and in some phylogenetic hypotheses, Lophotrochozoa may even be synonymous to Spiralia. Nemertea and Orthonectida (if not directly considered as part of Annelida) are probably lophotrochozoan phyla; Dicyemida, Gastrotricha, and Platyhelminthes may be lophotrochozoans ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protostome
Protostomia () is the clade of animals once thought to be characterized by the formation of the organism's mouth before its anus during embryonic development. This nature has since been discovered to be extremely variable among Protostomia's members, although the reverse is typically true of its sister clade, Deuterostomia. Well known examples of protostomes are arthropods, molluscs, annelids, flatworms and nematodes. They are also called schizocoelomates since schizocoely typically occurs in them. Together with the Deuterostomia and Xenacoelomorpha, these form the clade Bilateria, animals with bilateral symmetry, anteroposterior axis and three germ layers. Protostomy In animals at least as complex as earthworms, the first phase in gut development involves the embryo forming a dent on one side (the blastopore) which deepens to become its digestive tube (the archenteron). In the sister-clade, the deuterostomes (), the original dent becomes the anus while the gut eventually tu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spadella Cephaloptera
''Spadella'' is a genus of worms belonging to the family Spadellidae. The species of this genus are found in Europe, Northern America, Pacific Ocean. Species Species: *''Spadella angulata'' *''Spadella antarctica'' *''Spadella birostrata ''Spadella'' is a genus of worms belonging to the family Spadellidae. The species of this genus are found in Europe, Northern America, Pacific Ocean. Species Species: *''Spadella angulata'' *''Spadella antarctica ''Spadella'' is a genus of ...'' References {{Taxonbar, from=Q2330212 Chaetognatha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coelom
The coelom (or celom) is the main body cavity in most animals and is positioned inside the body to surround and contain the digestive tract and other organs. In some animals, it is lined with mesothelium. In other animals, such as molluscs, it remains undifferentiated. In the past, and for practical purposes, coelom characteristics have been used to classify bilaterian animal phyla into informal groups. Etymology The term ''coelom'' derives from the Ancient Greek word (), meaning 'cavity'. Structure Development The coelom is the mesodermally lined cavity between the gut and the outer body wall. During the development of the embryo, coelom formation begins in the gastrulation stage. The developing digestive tube of an embryo forms as a blind pouch called the archenteron. In Protostomes, the coelom forms by a process known as schizocoely. The archenteron initially forms, and the mesoderm splits into two layers: the first attaches to the body wall or ectoderm, forming ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plankton
Plankton are the diverse collection of organisms found in Hydrosphere, water (or atmosphere, air) that are unable to propel themselves against a Ocean current, current (or wind). The individual organisms constituting plankton are called plankters. In the ocean, they provide a crucial source of food to many small and large aquatic organisms, such as bivalves, fish and whales. Marine plankton include bacteria, archaea, algae, protozoa and drifting or floating animals that inhabit the saltwater of oceans and the brackish waters of estuaries. Freshwater plankton are similar to marine plankton, but are found in the freshwaters of lakes and rivers. Plankton are usually thought of as inhabiting water, but there are also airborne versions, the aeroplankton, that live part of their lives drifting in the atmosphere. These include plant spores, pollen and wind-scattered seeds, as well as microorganisms swept into the air from terrestrial dust storms and oceanic plankton swept into the air ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marine Worm
Any worm that lives in a marine environment is considered a marine worm. Marine worms are found in several different phyla, including the Platyhelminthes, Nematoda, Annelida (segmented worms), Chaetognatha, Hemichordata, and Phoronida. For a list of marine animals that have been called "sea worms", see sea worm. Reproduction Marine worms exhibit numerous types of reproduction, both sexually and asexually. Asexually many are able to reproduce via budding or regeneration. This regeneration is most notably studied in Plathelminths or Triclad, known for being one of the earliest animals to be studied for its regenerative capabilities. Marine worms will also sexually reproduce, internally and externally, with some releasing spawn into the ocean currents. This is in opposition to the much more internal and invasive method displayed by flat-worms called Penis fencing where hermaphroditic organisms will flight to try and impregnate their opponent while avoiding becoming impregnated. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
