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Enopla
Enopla is one of the classes of the worm phylum Nemertea, characterized by the presence of a peculiar armature of spines or plates in the proboscis. Evolution and systematics The record of nemerteans is extremely sparse, as would be expected from a soft-bodied animal. The Cambrian fossil, '' Amiskwia'', has been interpreted as a nemertean based on its resemblance to some pelagic ribbon worms; however, this interpretation is disputed by many paleontologists. The enoplan nemerteans have been regarded as highly derived based on a more complicated muscle arrangement in the body wall and a more complex nervous system. However, whether this is a plesiomorphic or apomorphic character is not clear, and recent molecular studies are inconclusive in this respect. Class Enopla used to be divided in two subclasses, Hoplonemertea and Bdellonemertea, but recent phylogenetic analyses based on nucleotide sequences show that Bdellonemertea should be included in Hoplonemertea. Hoplonemertea ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nemertea
Nemertea is a phylum of animals also known as ribbon worms or proboscis worms, consisting of 1300 known species. Most ribbon worms are very slim, usually only a few millimeters wide, although a few have relatively short but wide bodies. Many have patterns of yellow, orange, red and green coloration. The foregut, stomach and intestine run a little below the midline of the body, the anus is at the tip of the tail, and the mouth is under the front. A little above the gut is the rhynchocoel, a cavity which mostly runs above the midline and ends a little short of the rear of the body. All species have a proboscis which lies in the rhynchocoel when inactive but everts to emerge just above the mouth to capture the animal's prey with venom. A highly extensible muscle in the back of the rhynchocoel pulls the proboscis in when an attack ends. A few species with stubby bodies filter feed and have suckers at the front and back ends, with which they attach to a host. The brain is a rin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nemertea
Nemertea is a phylum of animals also known as ribbon worms or proboscis worms, consisting of 1300 known species. Most ribbon worms are very slim, usually only a few millimeters wide, although a few have relatively short but wide bodies. Many have patterns of yellow, orange, red and green coloration. The foregut, stomach and intestine run a little below the midline of the body, the anus is at the tip of the tail, and the mouth is under the front. A little above the gut is the rhynchocoel, a cavity which mostly runs above the midline and ends a little short of the rear of the body. All species have a proboscis which lies in the rhynchocoel when inactive but everts to emerge just above the mouth to capture the animal's prey with venom. A highly extensible muscle in the back of the rhynchocoel pulls the proboscis in when an attack ends. A few species with stubby bodies filter feed and have suckers at the front and back ends, with which they attach to a host. The brain is a rin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hoplonemertea
Hoplonemertea is an order of ribbon worms in the class Enopla. It contains two suborders: * Monostilifera * Polystilifera The proboscis is armed with one or more stylets; intestine The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. The GI tract contains all the major organs of the digestive system, in humans ... straight, mostly with paired lateral diverticula; no posterior ventral sucker. References Enopla Animal orders {{nemertean-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anopla
Anopla (for changes in taxonomy, see reference from 2019) has long been used as name for a class of marine worms of the phylum Nemertea, characterized by the absence of stylets on the proboscis, the mouth being below or behind the brain, and by having separate openings for the mouth and proboscis. The other long used class of Nemertea are the Enopla (for changes in taxonomy, see reference from 2019). Although Anopla is a paraphyletic grouping, it is used in almost all Scientific classifications. Anopla is divided into two orders: Palaeonemertea and Heteronemertea. Norenburg, J.; Gibson, R.; Herrera Bachiller, A.; Strand, M. (2019). World Nemertea Database. Anopla. Accessed through: World Register of Marine Species at: http://www.marinespecies.org/aphia.php?p=taxdetails&id=1293 on 2019-11-07 Palaeonemertea may be para- or polyphyletic, consisting of 3-5 groupings and totalling about 100 species. These worms have several apparently simple features and, as their name suggests, th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monostilifera
Monostilifera is a suborder of nemertean worms belonging to the class Enopla, a class of worms characterized by the presence of a peculiar armature of spines or plates in their proboscis. Families * Acteonemertidae * Amphiporidae * Carcinonemertidae * Cratenemertidae * Prosorhochmidae * Tetrastemmatidae Genus (unassigned family): ''Quasitetrastemma ''Quasitetrastemma'' is a genus of worms belonging to the order Monostilifera Monostilifera is a suborder of nemertean worms belonging to the class Enopla, a class of worms characterized by the presence of a peculiar armature of spines or plate ...'' Chernyshev, 2004 References Hoplonemertea {{Nemertean-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enoplea
Enoplea (enopleans) is a class, which with the classes SecernenteaTree of Life Web Project (ToL) (2002)Nematoda Version of January 1, 2002. Retrieved November 2, 2008. and Chromadorea make up the phylum Nematoda in current taxonomy. The Enoplea are considered to be a more ancestral group than the Chromadorea, and researchers have referred to its members as the "ancestrally diverged nematodes", compared to the "more recently diverged nematodes" of Chromadorea. Description The Enoplea are distinguished from the Chromadorea by a number of characteristics. The enoplean esophagus is cylindrical or "bottle-shaped", compared to the bulbous chromadorean esophagus. Enopleans have pocket-like amphids, while chromadoreans have amphids shaped like slits, pores, coils, or spirals. An enoplean is smooth or marked with fine lines, while a chromadorean may have rings, projections, or setae. The enoplean excretory system is simple, sometimes made up of a single cell, while chromadoreans have more ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prostoma
''Prostoma'' is a genus of freshwater Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. Although the term specifically excludes seawater and brackish water, it does include ... nemerteans, containing the following species: *'' Prostoma asensoriatum'' Montgomery, 1896 *'' Prostoma canadiensis'' Gibson & Moore, 1978 *'' Prostoma communopore'' Senz, 1996 *'' Prostoma eilhardi'' (Montgomery, 1894) *'' Prostoma graecense'' (Böhmig, 1892) *'' Prostoma hercegovinense'' Tarman, 1961 *'' Prostoma jenningsi'' Gibson & Young, 1971 *'' Prostoma kolasai'' Gibson & Moore, 1976 *'' Prostoma ohmiense'' Chernyshev ''et al.'', 1998 *'' Prostoma puteale'' Beauchamp, 1932 References External links * Tetrastemmatidae Nemertea genera {{nemertean-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxygen
Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as well as with other compounds. Oxygen is Earth's most abundant element, and after hydrogen and helium, it is the third-most abundant element in the universe. At standard temperature and pressure, two atoms of the element bind to form dioxygen, a colorless and odorless diatomic gas with the formula . Diatomic oxygen gas currently constitutes 20.95% of the Earth's atmosphere, though this has changed considerably over long periods of time. Oxygen makes up almost half of the Earth's crust in the form of oxides.Atkins, P.; Jones, L.; Laverman, L. (2016).''Chemical Principles'', 7th edition. Freeman. Many major classes of organic molecules in living organisms contain oxygen atoms, such as proteins, nucleic acids, carbohydrates, and fats, as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alga
Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular microalgae, such as ''Chlorella,'' ''Prototheca'' and the diatoms, to multicellular forms, such as the giant kelp, a large brown alga which may grow up to in length. Most are aquatic and autotrophic (they generate food internally) and lack many of the distinct cell and tissue types, such as stomata, xylem and phloem that are found in land plants. The largest and most complex marine algae are called seaweeds, while the most complex freshwater forms are the ''Charophyta'', a division of green algae which includes, for example, ''Spirogyra'' and stoneworts. No definition of algae is generally accepted. One definition is that algae "have chlorophyll ''a'' as their primary photosynthetic pigment and lack a sterile covering of cells around t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Benthic
The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from ancient Greek, βένθος (bénthos), meaning "the depths." Organisms living in this zone are called benthos and include microorganisms (e.g., bacteria and fungi) as well as larger invertebrates, such as crustaceans and polychaetes. Organisms here generally live in close relationship with the substrate and many are permanently attached to the bottom. The benthic boundary layer, which includes the bottom layer of water and the uppermost layer of sediment directly influenced by the overlying water, is an integral part of the benthic zone, as it greatly influences the biological activity that takes place there. Examples of contact soil layers include sand bottoms, rocky outcrops, coral, and bay mud. Description Oceans The benthic region of the ocean begins at the shore line (intertidal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Littoral
The littoral zone or nearshore is the part of a sea, lake, or river that is close to the shore. In coastal ecology, the littoral zone includes the intertidal zone extending from the high water mark (which is rarely inundated), to coastal areas that are permanently underwater, submerged — known as the ''foreshore'' — and the terms are often used interchangeably. However, the geographical meaning of ''littoral zone'' extends well beyond the intertidal zone to include all neritic waters within the bounds of continental shelves. Etymology The word ''littoral'' may be used both as a noun and as an adjective. It derives from the Latin language, Latin noun ''litus, litoris'', meaning "shore". (The doubled ''t'' is a late-medieval innovation, and the word is sometimes seen in the more classical-looking spelling ''litoral''.) Description The term has no single definition. What is regarded as the full extent of the littoral zone, and the way the littoral zone is divided into subregi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antarctic
The Antarctic ( or , American English also or ; commonly ) is a polar region around Earth's South Pole, opposite the Arctic region around the North Pole. The Antarctic comprises the continent of Antarctica, the Kerguelen Plateau and other island territories located on the Antarctic Plate or south of the Antarctic Convergence. The Antarctic region includes the ice shelves, waters, and all the island territories in the Southern Ocean situated south of the Antarctic Convergence, a zone approximately wide varying in latitude seasonally. The region covers some 20 percent of the Southern Hemisphere, of which 5.5 percent (14 million km2) is the surface area of the Antarctica continent itself. All of the land and ice shelves south of 60°S latitude are administered under the Antarctic Treaty System. Biogeographically, the Antarctic realm is one of eight biogeographic realms of Earth's land surface. Geography As defined by the Antarctic Treaty System, the Antarctic r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
