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Coral
Corals are colonial marine invertebrates within the class Anthozoa of the phylum Cnidaria. They typically form compact colonies of many identical individual polyps. Coral species include the important reef builders that inhabit tropical oceans and secrete calcium carbonate to form a hard skeleton. A coral "group" is a colony of very many genetically identical polyps. Each polyp is a sac-like animal typically only a few millimeters in diameter and a few centimeters in height. A set of tentacles surround a central mouth opening. Each polyp excretes an exoskeleton near the base. Over many generations, the colony thus creates a skeleton characteristic of the species which can measure up to several meters in size. Individual colonies grow by asexual reproduction of polyps. Corals also breed sexually by spawning: polyps of the same species release gametes simultaneously overnight, often around a full moon. Fertilized eggs form planulae, a mobile early form of the coral polyp which, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coral Reef
A coral reef is an underwater ecosystem characterized by reef-building corals. Reefs are formed of colonies of coral polyps held together by calcium carbonate. Most coral reefs are built from stony corals, whose polyps cluster in groups. Coral belongs to the class Anthozoa in the animal phylum Cnidaria, which includes sea anemones and jellyfish. Unlike sea anemones, corals secrete hard carbonate exoskeletons that support and protect the coral. Most reefs grow best in warm, shallow, clear, sunny and agitated water. Coral reefs first appeared 485 million years ago, at the dawn of the Early Ordovician, displacing the microbial and sponge reefs of the Cambrian. Sometimes called ''rainforests of the sea'', shallow coral reefs form some of Earth's most diverse ecosystems. They occupy less than 0.1% of the world's ocean area, about half the area of France, yet they provide a home for at least 25% of all marine species, including fish, mollusks, worms, crustaceans, echinoderms, sp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Great Barrier Reef
The Great Barrier Reef is the world's largest coral reef system composed of over 2,900 individual reefs and 900 islands stretching for over over an area of approximately . The reef is located in the Coral Sea, off the coast of Queensland, Australia, separated from the coast by a channel 100 miles wide in places and over 200 feet deep. The Great Barrier Reef can be seen from outer space and is the world's biggest single structure made by living organisms. This reef structure is composed of and built by billions of tiny organisms, known as coral polyps. It supports a wide diversity of life and was selected as a World Heritage Site in 1981. CNN labelled it one of the seven natural wonders of the world in 1997. Australian World Heritage places included it in its list in 2007. The Queensland National Trust named it a state icon of Queensland in 2006. A large part of the reef is protected by the Great Barrier Reef Marine Park, which helps to limit the impact of human use, such a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polyp (zoology)
A polyp in zoology is one of two forms found in the phylum Cnidaria, the other being the medusa. Polyps are roughly cylindrical in shape and elongated at the axis of the vase-shaped body. In solitary polyps, the aboral (opposite to oral) end is attached to the substrate by means of a disc-like holdfast called a pedal disc, while in colonies of polyps it is connected to other polyps, either directly or indirectly. The oral end contains the mouth, and is surrounded by a circlet of tentacles. Classes In the class Anthozoa, comprising the sea anemones and corals, the individual is always a polyp; in the class Hydrozoa, however, the individual may be either a polyp or a medusa, with most species undergoing a life cycle with both a polyp stage and a medusa stage. In class Scyphozoa, the medusa stage is dominant, and the polyp stage may or may not be present, depending on the family. In those scyphozoans that have the larval planula metamorphose into a polyp, the polyp, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tabulata
Tabulata, commonly known as tabulate corals, are an order of extinct forms of coral. They are almost always colonial, forming colonies of individual hexagonal cells known as corallites defined by a skeleton of calcite, similar in appearance to a honeycomb. Adjacent cells are joined by small pores. Their distinguishing feature is their well-developed horizontal internal partitions (''tabulae'') within each cell, but reduced or absent vertical internal partitions ( ''septa''). They are usually smaller than rugose corals, but vary considerably in shape, from flat to conical to spherical. Around 300 species have been described. Among the most common tabulate corals in the fossil record are ''Aulopora'', ''Favosites'', ''Halysites'', ''Heliolites'', ''Pleurodictyum'', ''Sarcinula'' and '' Syringopora''. Tabulate corals with massive skeletons often contain endobiotic symbionts, such as cornulitids and ''Chaetosalpinx''. Like rugose corals, they lived entirely during the Paleozoi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antipatharia
Antipatharians, also known as black corals or thorn corals, are an order of soft deep-water corals. These corals can be recognized by their jet-black or dark brown chitin skeletons, surrounded by the polyps (part of coral that is alive). Antipatharians are a cosmopolitan order, existing at nearly every location and depth, with the sole exception of brackish waters. However, they are most frequently found on continental slopes under deep. A black coral reproduces both sexually and asexually throughout its lifetime. Many black corals provide housing, shelter, food, and protection for other animals. Black corals were originally classified in the subclass Ceriantipatharia along with ceriantharians (tube-dwelling anemones), but were later reclassified under Hexacorallia. Though they have historically been used by Pacific Islanders for medical treatment and in rituals, its only modern use is making jewelry. Black corals have been declining in numbers and are expected to continue de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helioporacea
Helioporacea is an order of the subclass Octocorallia that forms massive lobed crystalline calcareous skeletons in colonial corals. These corals first appeared in the Cretaceous period. It consists of two families, Helioporidae Moseley, 1876Moseley, H. N. (1876). On the structure and relations of the alcyonarian ''Heliopora caerula'', with some account of the anatomy of a species of ''Sarcophyton'', notes on the structure of species of the genera ''Millepora'', ''Pocillopora'', and ''Stylaster'', and remarks on the affinities of certain palaeozoic corals. ''Philosophical Transactions of the Royal Society of London'', 166, 91–129. and Lithotelestidae Bayer & Muzik, 1977.Bayer, F. M. & Muzik, K. M. (1977). An Atlantic helioporan coral (Coelenterata: Octocorallia). ''Proceedings of the Biological Society of Washington'', 90(4), 975–984. The blue coral (''Heliopora coerulea''), the only extant species in the family Helioporidae, is most common in shallow water of the tropical Pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cloning
Cloning is the process of producing individual organisms with identical or virtually identical DNA, either by natural or artificial means. In nature, some organisms produce clones through asexual reproduction. In the field of biotechnology, cloning is the process of creating cloned organisms (copies) of Cell (biology), cells and of DNA fragments (molecular cloning). Etymology Coined by Herbert J. Webber, the term clone derives from the Ancient Greek word (), ''twig'', which is the process whereby a new plant is created from a twig. In botany, the term ''lusus'' was used. In horticulture, the spelling ''clon'' was used until the early twentieth century; the final ''e'' came into use to indicate the vowel is a "long o" instead of a "short o". Since the term entered the popular lexicon in a more general context, the spelling ''clone'' has been used exclusively. Natural cloning Cloning is a natural form of reproduction that has allowed life forms to spread for hundreds of millio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unicellular
A unicellular organism, also known as a single-celled organism, is an organism that consists of a single cell, unlike a multicellular organism that consists of multiple cells. Organisms fall into two general categories: prokaryotic organisms and eukaryotic organisms. All prokaryotes are unicellular and are classified into bacteria and archaea. Many eukaryotes are multicellular, but some are unicellular such as protozoa, unicellular algae, and unicellular fungi. Unicellular organisms are thought to be the oldest form of life, with early protocells possibly emerging 3.8–4.0 billion years ago. Although some prokaryotes live in colonies, they are not specialised cells with differing functions. These organisms live together, and each cell must carry out all life processes to survive. In contrast, even the simplest multicellular organisms have cells that depend on each other to survive. Most multicellular organisms have a unicellular life-cycle stage. Gametes, for example, are r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photosynthesis
Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that, through cellular respiration, can later be released to fuel the organism's activities. Some of this chemical energy is stored in carbohydrate molecules, such as sugars and starches, which are synthesized from carbon dioxide and water – hence the name ''photosynthesis'', from the Greek ''phōs'' (), "light", and ''synthesis'' (), "putting together". Most plants, algae, and cyanobacteria perform photosynthesis; such organisms are called photoautotrophs. Photosynthesis is largely responsible for producing and maintaining the oxygen content of the Earth's atmosphere, and supplies most of the energy necessary for life on Earth. Although photosynthesis is performed differently by different species, the process always begins when energy from light is absorbed by proteins called reaction centers that contain green chlorophyll (and other colored) pigments/chromoph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cnidocyte
A cnidocyte (also known as a cnidoblast or nematocyte) is an explosive cell containing one large secretory organelle called a cnidocyst (also known as a cnida () or nematocyst) that can deliver a sting to other organisms. The presence of this cell defines the phylum Cnidaria (corals, sea anemones, hydrae, jellyfish, etc.). Cnidae are used to capture prey and as a defense against predators. A cnidocyte fires a structure that contains a toxin within the cnidocyst; this is responsible for the stings delivered by a cnidarian. Structure and function Each cnidocyte contains an organelle called a cnida, cnidocyst, nematocyst, ptychocyst or spirocyst. This organelle consists of a bulb-shaped capsule containing a coiled hollow tubule structure attached to it. An immature cnidocyte is referred to as a cnidoblast or nematoblast. The externally oriented side of the cell has a hair-like trigger called a cnidocil, which is a mechano- and chemo-receptor. When the trigger is activated, the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fish
Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of living fish species are ray-finned fish, belonging to the class Actinopterygii, with around 99% of those being teleosts. The earliest organisms that can be classified as fish were soft-bodied chordates that first appeared during the Cambrian period. Although they lacked a true spine, they possessed notochords which allowed them to be more agile than their invertebrate counterparts. Fish would continue to evolve through the Paleozoic era, diversifying into a wide variety of forms. Many fish of the Paleozoic developed external armor that protected them from predators. The first fish with jaws appeared in the Silurian period, after which many (such as sharks) became formidable marine predators rather than just the prey of arthropods. Mos ... [...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] |
