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Asterina Pancerii
''Asterina pancerii'', commonly known as the seagrass asterina, is a species of starfish in the family Asterinidae. It is native to shallow parts of the Mediterranean Sea where it is usually found in seagrass meadows. Description ''Asterina pancerii'' is a very small starfish, seldom exceeding in diameter. It is pentagonal with five short, broad arms scarcely differentiated from the disc. The somewhat inflated aboral (upper) surface is covered by a mosaic of tiled plates each bearing a small tuft of three to eight regularly spaced crystalline spines. The marginal plates are fine, some bearing pedicellariae, and the tips of the arms have long, slender sensory tube feet and inconspicuous eyespots. The aboral surface is a radially symmetric star-shape of red, pink, purple and white plates; the oral (under) surface is a plain colour matching the main colour of the aboral surface. Distribution and habitat ''Asterina pancerii'' is endemic to the Mediterranean Sea. It is most common o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. Other ways of defining species include their karyotype, DNA sequence, morphology, behaviour or ecological niche. In addition, paleontologists use the concept of the chronospecies since fossil reproduction cannot be examined. The most recent rigorous estimate for the total number of species of eukaryotes is between 8 and 8.7 million. However, only about 14% of these had been described by 2011. All species (except viruses) are given a two-part name, a "binomial". The first part of a binomial is the genus to which the species belongs. The second part is called the specific name or the specific epithet (in botanical nomenclature, also sometimes i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genetic Testing
Genetic testing, also known as DNA testing, is used to identify changes in DNA sequence or chromosome structure. Genetic testing can also include measuring the results of genetic changes, such as RNA analysis as an output of gene expression, or through biochemical analysis to measure specific protein output. In a medical setting, genetic testing can be used to diagnose or rule out suspected genetic disorders, predict risks for specific conditions, or gain information that can be used to customize medical treatments based on an individual's genetic makeup. Genetic testing can also be used to determine biological relatives, such as a child's biological parentage (genetic mother and father) through DNA paternity testing, or be used to broadly predict an individual's ancestry. Genetic testing of plants and animals can be used for similar reasons as in humans (e.g. to assess relatedness/ancestry or predict/diagnose genetic disorders), to gain information used for selective breeding, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asterina (starfish)
''Asterina'' is a genus of asteroideans in the family Asterinidae. The species occurring in Australian waters are considered to not be congeneric with the type species ''A. gibbosa'' ( Pennant, 1777) by Rowe and Gates (1995), and will possibly to assigned to another genus or a new genus. Rowe and Gates (1995) also suggested that ''Asterina'' should be restricted to Atlantic waters.Rowe, F. & Gates, J. (1995). Echinodermata. In Wells, A. (Ed.), ''Zoological Catalogue of Australia'', Volume 33. Melbourne: CSIRO Australia. Species *'' Asterina fimbriata'' Perrier, 1875Perrier, E. (1875). ''Revision de la Collection de Stellerides du Museum d'Histoire Naturelle de Paris''. Paris: C. Reinwald. *''Asterina gibbosa'' ( Pennant, 1777) Pennant, T. (1777). ''British Zoology. Vol. IV. Crustacea. Mollusca. Testacea''. London: Benj. White. *'' Asterina gracilispina'' Clark, 1923Clark, H. L. (1923). The echinoderm fauna of South Africa. ''Annals of the South African Museum'', 13, 221–435. * ... [...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 Larval Ecology
Marine larval ecology is the study of the factors influencing dispersing larvae, which many marine invertebrates and fishes have. Marine animals with a larva typically release many larvae into the water column, where the larvae develop before metamorphosing into adults. Marine larvae can disperse over long distances, although determining the actual distance is challenging, because of their size and the lack of a good tracking method. Knowing dispersal distances is important for managing fisheries, effectively designing marine reserves, and controlling invasive species. Theories on the evolution of a biphasic life history Larval dispersal is one of the most important topics in marine ecology, today. Many marine invertebrates and many fishes have a bi-phasic life cycle with a pelagic larva or pelagic eggs that can be transported over long distances, and a demersal or benthic adult. There are several theories behind why these organisms have evolved this biphasic life history: *Larva ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Substrate (biology)
In biology, a substrate is the surface on which an organism (such as a plant, fungus, or animal) lives. A substrate can include biotic or abiotic materials and animals. For example, encrusting algae that lives on a rock (its substrate) can be itself a substrate for an animal that lives on top of the algae. Inert substrates are used as growing support materials in the hydroponic cultivation of plants. In biology substrates are often activated by the nanoscopic process of substrate presentation. In agriculture and horticulture * Cellulose substrate * Expanded clay aggregate (LECA) * Rock wool * Potting soil * Soil In animal biotechnology Requirements for animal cell and tissue culture Requirements for animal cell and tissue culture are the same as described for plant cell, tissue and organ culture (In Vitro Culture Techniques: The Biotechnological Principles). Desirable requirements are (i) air conditioning of a room, (ii) hot room with temperature recorder, (iii) microscope r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sequential Hermaphroditism
Sequential hermaphroditism (called dichogamy in botany) is a type of hermaphroditism that occurs in many fish, gastropods, and plants. Sequential hermaphroditism occurs when the individual changes its sex at some point in its life. In particular, a sequential hermaphrodite produces eggs (female gametes) and sperm (male gametes) at different stages in life. Species that can undergo these changes from one sex to another do so as a normal event within their reproductive cycle that is usually cued by either social structure or the achievement of a certain age or size. In animals, the different types of change are male to female (protandry or protandrous hermaphroditism), female to male (protogyny or protogynous hermaphroditism), bidirectional (serial or bidirectional hermaphroditism). Both protogynous and protandrous hermaphroditism allow the organism to switch between functional male and functional female. Bidirectional hermaphrodites have the capacity for sex change in either directi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Posidonia Oceanica
''Posidonia oceanica'', commonly known as Neptune grass or Mediterranean tapeweed, is a seagrass species that is endemic to the Mediterranean Sea. It forms large underwater meadows that are an important part of the ecosystem. The fruit is free floating and known in Italy as "the olive of the sea" (''l'oliva di mare''). Balls of fibrous material from its foliage, known as ''egagropili'' or ''Neptune balls'', wash up to nearby shorelines. The Posidonia has a very high carbon absorption capacity, being able to soak up 15 times more carbon dioxide every year than a similar sized piece of the Amazon rainforest. Morphology Posidonia oceanica has roots (which mainly serve to anchor the plant to the substrate), rhizome and tapeform leaves. The rhizomes, up to 1 cm thick, grow both horizontally (plagiotropic rhizomes), and vertically (orthotropic rhizomes). The former, thanks to the presence at the bottom of lignited roots up to 15 cm long, anchor the plant to the substrate. The latte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endemism
Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsewhere. For example, the Cape sugarbird is found exclusively in southwestern South Africa and is therefore said to be ''endemic'' to that particular part of the world. An endemic species can be also be referred to as an ''endemism'' or in scientific literature as an ''endemite''. For example '' Cytisus aeolicus'' is an endemite of the Italian flora. '' Adzharia renschi'' was once believed to be an endemite of the Caucasus, but it was later discovered to be a non-indigenous species from South America belonging to a different genus. The extreme opposite of an endemic species is one with a cosmopolitan distribution, having a global or widespread range. A rare alternative term for a species that is endemic is "precinctive", which applies to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Starfish
Starfish or sea stars are star-shaped echinoderms belonging to the class Asteroidea (). Common usage frequently finds these names being also applied to ophiuroids, which are correctly referred to as brittle stars or basket stars. Starfish are also known as asteroids due to being in the class Asteroidea. About 1,900 species of starfish live on the seabed in all the world's oceans, from warm, tropical zones to frigid, polar regions. They are found from the intertidal zone down to abyssal depths, at below the surface. Starfish are marine invertebrates. They typically have a central disc and usually five arms, though some species have a larger number of arms. The aboral or upper surface may be smooth, granular or spiny, and is covered with overlapping plates. Many species are brightly coloured in various shades of red or orange, while others are blue, grey or brown. Starfish have tube feet operated by a hydraulic system and a mouth at the centre of the oral or lower surface. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tube Feet
Tube feet (technically podia) are small active tubular projections on the oral face of an echinoderm, whether the arms of a starfish, or the undersides of sea urchins, sand dollars and sea cucumbers; they are more discreet though present on brittle stars, and have only a feeding function in feather stars. They are part of the water vascular system. Structure and function Tube feet function in locomotion, feeding, and respiration. The tube feet in a starfish are arranged in grooves along the arms. They operate through hydraulic pressure. They are used to pass food to the oral mouth at the center, and can attach to surfaces. A starfish that is inverted turns one arm over and attaches it to a solid surface, and levers itself the right way up. Tube feet allow these different types of animals to stick to the ocean floor and move slowly. Each tube foot consists of two parts: the ampulla and the podium. The ampulla is a water-filled sac contained in the body of the animal that contain ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pedicellaria
A pedicellaria (plural: pedicellariae) is a small wrench- or claw-shaped appendage with movable jaws, called valves, commonly found on echinoderms (phylum Echinodermata), particularly in sea stars (class Asteroidea) and sea urchins (class Echinoidea). Each pedicellaria is an effector organ with its own set of muscles, neuropils, and sensory receptors and is therefore capable of reflex responses to the environment. Pedicellariae are poorly understood but in some taxa, they are thought to keep the body surface clear of algae, encrusting organisms, and other debris in conjunction with the ciliated epidermis present in all echinoderms. In sea stars Types There are two major types of pedicellaria in sea stars: straight and crossed. Straight pedicellaria are typically larger and located on the body surface, whereas crossed pedicellaria are smaller and found more commonly on stalks, raised above the body surface or in clumps circling the spines. The crossed type is connected to th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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