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Parasagitta Setosa
''Parasagitta setosa'' is a small arrow worm in the family Sagittidae, previously referred to as ''Sagitta setosa''. It is native to the northeastern Atlantic Ocean, the North Sea and the Mediterranean Sea, and also occurs in the Baltic Sea and the Black Sea. Description ''Parasagitta setosa'' grows to a maximum length of , its tail being up to a quarter of this length. It is a thin, transparent, flexible worm with two pairs of rounded lateral fins composed completely of ray-like structures. There are eight to nine curved grasping hooks on the head. The teeth are in two rows, with six to eight in the front row and ten to sixteen at the back. The eyes have a star-shaped segment spot and the collarette is small or not present at all. The seminal vesicles are very near the posterior fins which are separated from the caudal fin. Distribution ''Parasagitta setosa'' is a common neritic species forming part of the plankton in waters less than about 200 metres deep. It occurs in the n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Johannes Peter Müller
Johannes Peter Müller (14 July 1801 – 28 April 1858) was a German physiologist, comparative anatomy, comparative anatomist, ichthyology, ichthyologist, and herpetology, herpetologist, known not only for his discoveries but also for his ability to synthesize knowledge. The paramesonephric duct (Müllerian duct) was named in his honor. Life Early years and education Müller was born in Koblenz, Coblenz. He was the son of a poor shoemaker, and was about to be apprenticed to a saddler when his talents attracted the attention of his teacher, and he prepared himself to become a Roman Catholic Priest. During his Secondary school, college course in Koblenz, he devoted himself to the classics and made his own translations of Aristotle. At first, his intention was to become a priest. When he was eighteen, his love for natural science became dominant, and he turned to medicine, entering the University of Bonn in 1819. There he received his Doctor of Medicine, M.D. in 1822. He then studie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Food Chain
A food chain is a linear network of links in a food web starting from producer organisms (such as grass or algae which produce their own food via photosynthesis) and ending at an apex predator species (like grizzly bears or killer whales), detritivores (like earthworms or woodlice), or decomposer species (such as fungi or bacteria). A food chain also shows how organisms are related to each other by the food they eat. Each level of a food chain represents a different trophic level. A food chain differs from a food web because the complex network of different animals' feeding relations are aggregated and the chain only follows a direct, linear pathway of one animal at a time. Natural interconnections between food chains make it a food web. Food chains were first introduced by the Arab scientist and philosopher Al-Jahiz in the 10th century and later popularized in a book published in 1927 by Charles Elton, which also introduced the food web concept. A common metric used to quant ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anchovy
An anchovy is a small, common forage fish of the family Engraulidae. Most species are found in marine waters, but several will enter brackish water, and some in South America are restricted to fresh water. More than 140 species are placed in 17 genera; they are found in the Atlantic, Indian and Pacific Oceans, and in the Black Sea and the Mediterranean Sea. Anchovies are usually classified as oily fish. Genera Characteristics Anchovies are small, green fish with blue reflections due to a silver-colored longitudinal stripe that runs from the base of the caudal (tail) fin. They range from in adult length, and their body shapes are variable with more slender fish in northern populations. The snout is blunt with tiny, sharp teeth in both jaws. The snout contains a unique rostral organ, believed to be electro-sensory in nature, although its exact function is unknown. The mouth is larger than that of herrings and silversides, two fish which anchovies closely resemble in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mnemiopsis
''Mnemiopsis leidyi'', the warty comb jelly or sea walnut, is a species of tentaculate ctenophore (comb jelly). It is native to western Atlantic coastal waters, but has become established as an invasive species in European and western Asian regions. Three species have been named in the genus ''Mnemiopsis'', but they are now believed to be different ecological forms of a single species ''M. leidyi'' by most zoologists. Description and ecology ''Mnemiopsis'' have an oval-shaped and transparent lobed body, with four rows of ciliated combs that run along the body vertically and glow blue-green when disturbed. They have several feeding tentacles. Unlike cnidarians, ''Mnemiopsis'' does not sting. Their body comprises 97% water. They have a maximum body length of roughly and a diameter of . It is euryoecious, tolerating a wide range of salinity (2 to 38 psu), temperature (), and water quality. ''Mnemiopsis'' is a carnivore that consumes zooplankton including crustaceans, other com ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ctenophora
Ctenophora (; ctenophore ; ) comprise a phylum of marine invertebrates, commonly known as comb jellies, that inhabit sea waters worldwide. They are notable for the groups of cilia they use for swimming (commonly referred to as "combs"), and they are the largest animals to swim with the help of cilia. Depending on the species, adult ctenophores range from a few millimeters to in size. Only 100 to 150 species have been validated, and possibly another 25 have not been fully described and named. The textbook examples are cydippids with egg-shaped bodies and a pair of retractable tentacles fringed with tentilla ("little tentacles") that are covered with colloblasts, sticky cells that capture prey. Their bodies consist of a mass of jelly, with a layer two cells thick on the outside, and another lining the internal cavity. The phylum has a wide range of body forms, including the egg-shaped cydippids with retractable tentacles that capture prey, the flat generally combless plat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Muggiaea Atlantica
''Muggiaea atlantica'' is a species of small hydrozoan, a siphonophore in the family Diphyidae. It is a cosmopolitan species occurring in inshore waters of many of the world's oceans, and it has colonised new areas such as the North Sea and the Adriatic Sea. It is subject to large population swings, and has been held responsible for the death of farmed salmon in Norway. The species was first described by J.T. Cunningham in 1892 from a specimen obtained at Plymouth, England. Description ''Muggiaea atlantica'' is a small colonial siphonophore, but one of the two nectophores (swimming bells) is undeveloped. The remaining nectophore grows to a length of about . It is translucent and has five straight, longitudinal ridges, some of which may form a keel. The hydroecium (ventral cavity) is about one third of the length of the nectophore, and the long slender somatocyst (extension of the gastrovascular system) reaches the apex of the nectosac (central cavity) and sometimes contains oi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Siphonophorae
Siphonophorae (from Greek ''siphōn'' 'tube' + ''pherein'' 'to bear') is an order within Hydrozoa, which is a class of marine organisms within the phylum Cnidaria. According to the World Register of Marine Species, the order contains 175 species thus far. Although a siphonophore may appear to be an individual organism, each specimen is in fact a colonial organism composed of medusoid and polypoid zooids that are morphologically and functionally specialized. Zooids are multicellular units that develop from a single fertilized egg and combine to create functional colonies able to reproduce, digest, float, maintain body positioning, and use jet propulsion to move. Most colonies are long, thin, transparent floaters living in the pelagic zone. Like other hydrozoans, some siphonophores emit light to attract and attack prey. While many sea animals produce blue and green bioluminescence, a siphonophore in the genus ''Erenna'' was only the second life form found to produce a red li ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pleurobrachia Pileus
''Pleurobrachia pileus'' is a species of comb jelly, commonly known as a sea gooseberry. It is found in open water in the northern Atlantic Ocean, the North Sea, the Baltic Sea and the Black Sea, and was first described by the Danish zoologist Otto Friedrich Müller in 1776. Description ''Pleurobrachia pileus'' is a small, globular or ovoid comb jelly up to about in length. It has a pair of long tentacles that are used to catch prey and can be retracted into sheaths. The tentacles are up to twenty times the length of the body and are fringed with filaments along one edge. The body bears four pairs of longitudinal rows of cilia known as combs which extend about three quarters the length of the animal between its mouth and its aboral (opposite) end. The cilia are mounted on short transverse plates which are bioluminescent. It is the beating of the cilia in synchrony that allows the animal to swim and that gives it an iridescent appearance. The body is transparent and the comb ro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oikopleura
''Oikopleura'' is a genus of Tunicata (sea-squirts) in the class Appendicularia. It forms a mucus house every four hours at 20 degrees Celsius. This house has a coarse mesh to keep out big particles, and a fine mesh that collects the small particles, down to the nanoplankton that includes (pelagic) bacteria. Abandoned mucus houses sink to the deep, collecting organic particles during their descent. They make an important contribution to marine snow, since ''Oikopleura'' is abundant and is a very active filterer, using powerful strokes of its tail. Its abundance is less obvious from preserved samples (that are usually analyzed) because the gelatinous body disappears in the preservation process while leaving hardly any trace. Species of ''Oikopleura ''have the smallest genomes in the animal kingdom, only about 75 Mb. ''Oikopleura'' contains bioluminescent species. About half of ''Oikopleura'' species are bioluminescent. Taxonomy * ''Oikopleura (Coecaria)'' , 1933 ** ''Oikopleu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Copepod
Copepods (; meaning "oar-feet") are a group of small crustaceans found in nearly every freshwater and saltwater habitat (ecology), habitat. Some species are planktonic (inhabiting sea waters), some are benthos, benthic (living on the ocean floor), a number of species have parasitic phases, and some continental species may live in limnoterrestrial habitats and other wet terrestrial places, such as swamps, under leaf fall in wet forests, bogs, springs, ephemeral ponds, and puddles, damp moss, or water-filled recesses (phytotelmata) of plants such as bromeliads and pitcher plants. Many live underground in marine and freshwater caves, sinkholes, or stream beds. Copepods are sometimes used as Ecological indicator, biodiversity indicators. As with other crustaceans, copepods have a larval form. For copepods, the egg hatches into a Crustacean larvae#Nauplius, nauplius form, with a head and a tail but no true thorax or abdomen. The larva molts several times until it resembles the adult an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Predation
Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill the host) and parasitoidism (which always does, eventually). It is distinct from scavenging on dead prey, though many predators also scavenge; it overlaps with herbivory, as seed predators and destructive frugivores are predators. Predators may actively search for or pursue prey or wait for it, often concealed. When prey is detected, the predator assesses whether to attack it. This may involve ambush or pursuit predation, sometimes after stalking the prey. If the attack is successful, the predator kills the prey, removes any inedible parts like the shell or spines, and eats it. Predators are adapted and often highly specialized for hunting, with acute senses such as vision, hearing, or smell. Many predatory animals, both vertebrate and inv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermocline
A thermocline (also known as the thermal layer or the metalimnion in lakes) is a thin but distinct layer in a large body of fluid (e.g. water, as in an ocean or lake; or air, e.g. an atmosphere) in which temperature changes more drastically with depth than it does in the layers above or below. In the ocean, the thermocline divides the upper mixed layer from the calm deep water below. Depending largely on season, latitude, and turbulent mixing by wind, thermoclines may be a semi-permanent feature of the body of water in which they occur, or they may form temporarily in response to phenomena such as the radiative heating/cooling of surface water during the day/night. Factors that affect the depth and thickness of a thermocline include seasonal weather variations, latitude, and local environmental conditions, such as tides and currents. Oceans Most of the heat energy of the sunlight that strikes the Earth is absorbed in the first few centimeters at the ocean's surface, which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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