The maxima clam known as the small giant clam, is a species of bivalve mollusc found throughout the Indo-Pacific region. They are much sought after in the aquarium trade, as their striking coloration mimics that of the true giant clam. Bivalves have two valves on the mantle; these siphon water through the body to extract oxygen from the water using the gills and to feed on algae. The maxima is less than one-third the size of the true giant clam. Adults develop a large shell that adheres to the substrate by its byssus, a tuft of long, tough filaments that protrude from a hole next to the hinge; when open, the bright blue, green or brown mantle is exposed and obscures the edges of the shell which have prominent, distinctive furrows. The attractive colours of the small giant clam are the result of crystalline pigment cells; these are thought to protect the clam from the effects of intense sunlight, or bundle light to enhance the algae's photosynthesis. Maxima produce the color white in their mantle by clustering red and green cells, while individual T. derasa cells are themselves multi-colored.
The small giant clam has the widest range of all giant clam species. It is found in the oceans surrounding east Africa, China, Southeast Asia, the Red Sea and the islands of the Pacific. Found living on the surface of reefs or sand, or embedded in coral, the small giant clam occupies well-lit areas, due to its symbiotic relationship with photosynthetic algae, which require sunlight for energy production. A sessile mollusc, the small giant clam attaches itself to rocks or dead coral and siphons water through its body, filtering it for phytoplankton, as well as extracting oxygen with its gills. However, it does not need to filter-feed as much as other clams since it obtains most of the nutrients it requires from tiny photosynthetic algae known as zooxanthellae. Beginning life as a tiny fertilised egg, the small giant clam hatches within 12 hours, becoming a free-swimming larva; this larva develops into another, more developed, larva, capable of filter-feeding. At the third larval stage, a foot develops, allowing the larva to alternately swim and rest on the substrate.
After eight to ten days, the larva metamorphoses into a juvenile clam, at which point it can acquire zooxanthellae and function symbiotically. The juvenile matures into a male clam after two or three years, becoming a hermaphrodite when larger. Reproduction is stimulated by the lunar cycle, the time of day, the presence of other eggs and sperm in the water. Hermaphroditic clams release their sperm first followed by their eggs, thereby avoiding self-fertilisation; this article incorporates text from the ARKive fact-file "Maxima clam" under the Creative Commons Attribution-ShareAlike 3.0 Unported License and the GFDL. Maxima clam media from ARKive Stephen D. A. Smith and population dynamics of the giant clam Tridacna maxima at its southern limit of distribution in coastal, subtropical eastern Australia.
Porcelain is a ceramic material made by heating materials including kaolin, in a kiln to temperatures between 1,200 and 1,400 °C. The toughness and translucence of porcelain, relative to other types of pottery, arises from vitrification and the formation of the mineral mullite within the body at these high temperatures. Though definitions vary, porcelain can be divided into three main categories: hard-paste, soft-paste and bone china; the category that an object belongs to depends on the composition of the paste used to make the body of the porcelain object and the firing conditions. Porcelain evolved in China and was achieved at some point about 2,000 to 1,200 years ago slowly spread to other East Asian countries, Europe and the rest of the world, its manufacturing process is more demanding than that for earthenware and stoneware, the two other main types of pottery, it has been regarded as the most prestigious type of pottery for its delicacy and its white colour. It combines well with both glazes and paint, can be modelled well, allowing a huge range of decorative treatments in tablewares and figurines.
It has many uses in technology and industry. The European name, porcelain in English, come from the old Italian porcellana because of its resemblance to the surface of the shell. Porcelain is referred to as china or fine china in some English-speaking countries, as it was first seen in imports from China. Properties associated with porcelain include low elasticity. Porcelain has been described as being "completely vitrified, impermeable, white or artificially coloured and resonant". However, the term "porcelain" lacks a universal definition and has "been applied in an unsystematic fashion to substances of diverse kinds which have only certain surface-qualities in common". Traditionally, East Asia only classifies pottery into low-fired wares and high-fired wares, without the European concept of stoneware, high-fired but not white or translucent. Terms such as "proto-porcelain", "porcellaneous" or "near-porcelain" may be used in cases where the ceramic body approaches whiteness and translucency.
Kaolin is the primary material from which porcelain is made though clay minerals might account for only a small proportion of the whole. The word paste is an old term for both the fired materials. A more common terminology for the unfired material is "body"; the composition of porcelain is variable, but the clay mineral kaolinite is a raw material. Other raw materials can include feldspar, ball clay, bone ash, quartz and alabaster; the clays used are described as being long or short, depending on their plasticity. Long clays have high plasticity. In soil mechanics, plasticity is determined by measuring the increase in content of water required to change a clay from a solid state bordering on the plastic, to a plastic state bordering on the liquid, though the term is used less formally to describe the ease with which a clay may be worked. Clays used for porcelain are of lower plasticity and are shorter than many other pottery clays, they wet quickly, meaning that small changes in the content of water can produce large changes in workability.
Thus, the range of water content within which these clays can be worked is narrow and must be controlled. The following section provides background information on the methods used to form, finish and fire ceramic wares. Unlike their lower-fired counterparts, porcelain wares do not need glazing to render them impermeable to liquids and for the most part are glazed for decorative purposes and to make them resistant to dirt and staining. Many types of glaze, such as the iron-containing glaze used on the celadon wares of Longquan, were designed for their striking effects on porcelain. Biscuit porcelain is unglazed. Porcelain wares may be decorated under the glaze using pigments that include cobalt and copper or over the glaze using coloured enamels. Like many earlier wares, modern porcelains are biscuit-fired at around 1,000 °C, coated with glaze and sent for a second glaze-firing at a temperature of about 1,300 °C or greater. Another early method is "once-fired", where the glaze is applied to the unfired body and the two fired together in a single operation.
In this process, "green" ceramic wares are heated to high temperatures in a kiln to permanently set their shapes. Porcelain is fired at a higher temperature than earthenware so that the body can vitrify and become non-porous. Porcelain originated in China, it took a long time to reach the modern material; until recent times all East Asian porcelain was of the hard-paste type. There is no precise date to separate the production of proto-porcelain from that of porcelain. Although proto-porcelain wares exist dating from the Shang dynasty, by the time of the Eastern Han dynasty period, glazed ceramic wares had developed into porcelain, which Chinese defined as high-fired ware. By the late Sui dynasty and early Tang dynasty the additional Western requirements of whiteness and translucency had b
The mantle is a significant part of the anatomy of molluscs: it is the dorsal body wall which covers the visceral mass and protrudes in the form of flaps well beyond the visceral mass itself. In many species of molluscs the epidermis of the mantle secretes calcium carbonate and conchiolin, creates a shell. In sea slugs there is a progressive loss of the shell and the mantle becomes the dorsal surface of the animal; the words mantle and pallium both meant cloak or cape, see mantle. This anatomical structure in molluscs resembles a cloak because in many groups the edges of the mantle referred to as the mantle margin, extend far beyond the main part of the body, forming flaps, double-layered structures which have been adapted for many different uses, including for example, the siphon; the mantle cavity is a central feature of molluscan biology. This cavity is formed by a double fold of mantle which encloses a water space; this space contains the mollusc's gills, osphradium and gonopores. The mantle cavity functions as a respiratory chamber in most molluscs.
In bivalves it is part of the feeding structure. In some molluscs the mantle cavity is a brood chamber, in cephalopods and some bivalves such as scallops, it is a locomotory organ; the mantle is muscular. In cephalopods the contraction of the mantle is used to force water through a tubular siphon, the hyponome, this propels the animal rapidly through the water. In gastropods it is used as a kind of "foot" for locomotion over the surface. In Patella the foot includes the entire ventral surface of the animal; the foot of the Bivalvia is a fleshy process adapted by its form to digging rather than to locomotion. In shelled molluscs, the mantle is the organ that forms the shell, adds to the shell to increase its size and strength as the animal grows. Shell material is secreted by the ectodermic cells of the mantle tissue; the mantle of many gastropods is fully or hidden inside the gastropod shell. In species where the shell is small compared to the size of the body, more of the mantle shows. Shell-less slugs have the mantle visible.
The dorsal surface of the mantle is called the notum, while the ventral surface of the mantle is called the hyponotum. In the family Philomycidae, the mantle covers the whole back side of the body. Mollusc shell, formed by the mantle Siphon, a part of the mantle in some groups of molluscs
Sessility is the biological property of an organism describing its lack of a means of self-locomotion. Absent natural motility sessile organisms are immobile; this is distinct from the botanical meaning of sessility, which refers to an organism or biological structure attached directly by its base without a stalk. Sessile organisms can move via external forces, but are permanently attached to something. Organisms such as corals lay down their own substrate from. Other sessile organisms grow from a solid such as a rock, dead tree trunk, or a manmade object such as a buoy or ship's hull. Sessile animals have a motile phase in their development. Sponges have a motile larval stage. In contrast, many jellyfish develop as sessile polyps early in their life cycle. In the case of the cochineal, it is in the nymph stage; the juveniles produce long wax filaments. They move to the edge of the cactus pad where the wind catches the wax filaments and carries the tiny larval cochineals to a new host. Many sessile animals, including sponges and hydra, are capable of asexual reproduction in situ by the process of budding.
Sessile organisms such as barnacles and tunicates need some mechanism to move their young into new territory. This is why the most accepted theory explaining the evolution of a larval stage is the need for long-distance dispersal ability. Biologist Wayne Sousa's 1979 study in intertidal disturbance added support for the theory of nonequilibrium community structure, “suggesting that open space is necessary for the maintenance of diversity in most communities of sessile organisms.” Clumping is a behavior in sessile organisms, in which individuals of a particular species group to one another for beneficial purposes, can be seen in coral reefs and cochineal populations. This allows for better protection from predators; the circalittoral zone of coastal environments and biomes are dominated by sessile organisms such as oysters. Carbonate platforms grow due to the buildup of skeletal remains of sessile organisms microorganisms, which induce carbonate precipitation through their metabolism. In anatomy and botany, sessility refers to an organism or biological structure that has no peduncle or stalk.
See peduncle and sessility. A sessile structure has no stalk. Anthozoa Ediacara biota
Symbiosis is any type of a close and long-term biological interaction between two different biological organisms, be it mutualistic, commensalistic, or parasitic. The organisms, each termed a symbiont, may be of different species. In 1879, Heinrich Anton de Bary defined it as "the living together of unlike organisms"; the term was subject to a century-long debate about whether it should denote mutualism, as in lichens. Symbiosis can be obligatory, which means that one or both of the symbionts depend on each other for survival, or facultative when they can live independently. Symbiosis is classified by physical attachment; when one organism lives on the surface of another, such as head lice on humans, it is called ectosymbiosis. The definition of symbiosis was a matter of debate for 130 years. In 1877, Albert Bernhard Frank used the term symbiosis to describe the mutualistic relationship in lichens. In 1879, the German mycologist Heinrich Anton de Bary defined it as "the living together of unlike organisms".
The definition has varied among scientists, with some advocating that it should only refer to persistent mutualisms, while others thought it should apply to all persistent biological interactions, in other words mutualisms, commensalism, or parasitism, but excluding brief interactions such as predation. Current biology and ecology textbooks use the latter "de Bary" definition, or an broader one where symbiosis means all interspecific interactions. In 1949, Edward Haskell proposed an integrative approach, proposing a classification of "co-actions" adopted by biologists as "interactions". Biological interactions can involve individuals of the same species or individuals of different species; these can be further classified by either the mechanism of the interaction or the strength and direction of their effects. Relationships can be obligate, meaning that one or both of the symbionts depend on each other for survival. For example, in lichens, which consist of fungal and photosynthetic symbionts, the fungal partners cannot live on their own.
The algal or cyanobacterial symbionts in lichens, such as Trentepohlia, can live independently, their symbiosis is, facultative. Endosymbiosis is any symbiotic relationship in which one symbiont lives within the tissues of the other, either within the cells or extracellularly. Examples include diverse microbiomes, nitrogen-fixing bacteria that live in root nodules on legume roots. Ectosymbiosis is any symbiotic relationship in which the symbiont lives on the body surface of the host, including the inner surface of the digestive tract or the ducts of exocrine glands. Examples of this include ectoparasites such as lice. Competition can be defined as an interaction between organisms or species, in which the fitness of one is lowered by the presence of another. Limited supply of at least one resource used by both facilitates this type of interaction, although the competition may exist over other'amenities', such as females for reproduction. Mutualism or interspecies reciprocal altruism is a long-term relationship between individuals of different species where both individuals benefit.
Mutualistic relationships may be either obligate for both species, obligate for one but facultative for the other, or facultative for both. A large percentage of herbivores have mutualistic gut flora to help them digest plant matter, more difficult to digest than animal prey; this gut flora is made up of cellulose-digesting protozoans or bacteria living in the herbivores' intestines. Coral reefs are the result of mutualisms between coral organisms and various types of algae which live inside them. Most land plants and land ecosystems rely on mutualisms between the plants, which fix carbon from the air, mycorrhyzal fungi, which help in extracting water and minerals from the ground. An example of mutualism is the relationship between the ocellaris clownfish that dwell among the tentacles of Ritteri sea anemones; the territorial fish protects the anemone from anemone-eating fish, in turn the stinging tentacles of the anemone protect the clownfish from its predators. A special mucus on the clownfish protects it from the stinging tentacles.
A further example is a fish which sometimes lives together with a shrimp. The shrimp cleans up a burrow in the sand in which both the shrimp and the goby fish live; the shrimp is blind, leaving it vulnerable to predators when outside its burrow. In case of danger, the goby touches the shrimp with its tail to warn it; when that happens both the shrimp and goby retreat into the burrow. Different species of gobies clean up ectoparasites in other fish another kind of mutualism. A non-obligate symbiosis is seen in encru
Jean-Baptiste Pigalle was a French sculptor. Pigalle was born in the seventh child of a carpenter. Although he failed to obtain the Prix de Rome, after a severe struggle he entered the Académie Royale and became one of the most popular sculptors of his day, his earlier work, such as Child with Cage and Mercury Fastening his Sandals, is less commonplace than that of his more mature years, but his nude statue of Voltaire, dated 1776, his tombs of Comte d'Harcourt and of Marshal Saxe, completed in 1777, are good examples of French sculpture in the 18th century. Pigalle taught the sculptor Louis-Philippe Mouchy, who married his niece, who copied Pigalle's style, he is said to have taught the painter Madeleine-Élisabeth Pigalle, believed to be a distant relative from Sens. His name is most known today because of the Pigalle red-light district in Paris, located around the square of the same name. Pigalle died in Paris on 20 August 1785. Media related to Jean-Baptiste Pigalle at Wikimedia Commons Virtual Gallery Jean-Baptiste Pigalle in American public collections, on the French Sculpture Census website
An aquarium is a vivarium of any size having at least one transparent side in which aquatic plants or animals are kept and displayed. Fishkeepers use aquaria to keep fish, amphibians, aquatic reptiles such as turtles, aquatic plants; the term "aquarium", coined by English naturalist Philip Henry Gosse, combines the Latin root aqua, meaning water, with the suffix -arium, meaning "a place for relating to". The aquarium principle was developed in 1850 by the chemist Robert Warington, who explained that plants added to water in a container would give off enough oxygen to support animals, so long as the numbers of animals did not grow too large; the aquarium craze was launched in early Victorian England by Gosse, who created and stocked the first public aquarium at the London Zoo in 1853, published the first manual, The Aquarium: An Unveiling of the Wonders of the Deep Sea in 1854. An aquarium is a water-filled tank. Small aquariums are kept in the home by hobbyists. There are larger public aquariums in many cities.
This kind of aquarium is other aquatic animals in large tanks. A large aquarium may have otters, turtles and other sea animals. Most aquarium tanks have plants. An aquarist owns fish or maintains an aquarium constructed of glass or high-strength acrylic. Cuboid aquaria are known as fish tanks or tanks, while bowl-shaped aquaria are known as fish bowls. Size can range from a small glass bowl, under a gallon in volume, to immense public aquaria of several thousand gallons. Specialized equipment maintains appropriate water quality and other characteristics suitable for the aquarium's residents. In 1369, the Hongwu Emperor of China established a porcelain company that produced large porcelain tubs for maintaining goldfish. Leonhard Baldner, who wrote Vogel-, Fisch- und Tierbuch in 1666, maintained weather loaches and newts, it is sometimes held that the aquarium was invented by the Romans, who are said to have kept sea barbels in marble-and-glass tanks, but this is unlikely to be true. In 1832, Jeanne Villepreux-Power, a pioneering French marine biologist, became the first person to create aquaria for experimenting with aquatic organisms.
In 1836, soon after his invention of the Wardian case, Dr. Nathaniel Bagshaw Ward proposed to use his tanks for tropical animals. In 1841 he did so, though only with toy fish. However, he soon housed real animals. In 1838, Félix Dujardin noted owning a saltwater aquarium. In 1846, Anne Thynne maintained stony corals and seaweed for three years, was credited as the creator of the first balanced marine aquarium in London. English chemist Robert Warington experimented with a 13-gallon container, which contained goldfish and snails, creating one of the first stable aquaria; the aquarium principle was developed by Warington, explaining that plants added to water in a container would give off enough oxygen to support animals, so long as their numbers do not grow too large. He published his findings in 1850 in the Chemical Society's journal; the keeping of fish in an aquarium spread quickly. In the United Kingdom, it became popular after ornate aquaria in cast-iron frames were featured at the Great Exhibition of 1851.
In 1853, the aquarium craze was launched in England by Philip Henry Gosse who created and stocked the first public aquarium in the London Zoo which came to be known as the Fish House. Gosse coined the word "aquarium", opting for this term in 1854 in his book The Aquarium: An Unveiling of the Wonders of the Deep Sea. In this book, Gosse discussed saltwater aquaria. In the 1850s, the aquarium became a fad in the United Kingdom. Tank designs and techniques for maintaining water quality were developed by Warington cooperating with Gosse until his critical review of the tank water composition. Edward Edwards developed these glass-fronted aquaria in his 1858 patent for a "dark-water-chamber slope-back tank", with water circulating to a reservoir beneath. Germans soon rivaled the British in their interest. In 1854, an anonymous author had two articles published about the saltwater aquaria of the United Kingdom: Die Gartenlaube entitled Der Ocean auf dem Tische. However, in 1856, Der See im Glase was published, discussing freshwater aquaria, which were much easier to maintain in landlocked areas.
In 1862 William Alford Lloyd bankrupt because of the craze in England being over, moved to Grindel Dammthor, Hamburg, to supervise the installation of the circulating system and tanks at the Hamburg Aquarium. During the 1870s, some of the first aquarist societies were appearing in Germany; the United States soon followed. Published in 1858, Henry D. Butler's The Family Aquarium was one of the first books written in the United States about the aquarium. According to the July issue of The North American Review of the same year, William Stimson may have owned some of the first functional aquaria, had as many as seven or eight; the first aquarist society in the United States was founded in New York City in 1893, followed by others. The New York Aquarium Journal, first published in October 1876, is considered to be the world's first aquarium magazine. In the Victorian era in the United Kingdom, a common design for the home aquarium was a glass front with the other sides made of wood; the bottom would be heated from below.
More advanced systems soon began to be introduced, along with tanks of