Benjamin Moore Personal Color Viewer 2.0

Bivalvia Wikipedia. Bivalvia, in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of marine and freshwater molluscs that have laterally compressed bodies enclosed by a shell consisting of two hinged parts. Bivalves as a group have no head and they lack some usual molluscan organs like the radula and the odontophore. They include the clams, oysters, cockles, mussels, scallops, and numerous other families that live in saltwater, as well as a number of families that live in freshwater. MTV originally an initialism of Music Television is an American cable and satellite television channel owned by Viacom Media Networks a division of Viacom and. Microsoft has essentially conceded that theres no demand for the personal finance software product. Heres what you need to know. Tabtight professional, free when you need it, VPN service. SCI FI Channel is now Syfy, but you can still get access to all your favorite SCI FI Channel content right here. Syfy features science fiction, drama, supernatural. The Hollywood Reporter is your source for breaking news about Hollywood and entertainment, including movies, TV, reviews and industry blogs. The Walt Disney Company is facing a lawsuit alleging it violated federal law aimed at protecting childrens online privacy. The company allegedly allowed ad tech. The majority are filter feeders. The gills have evolved into ctenidia, specialised organs for feeding and breathing. Most bivalves bury themselves in sediment where they are relatively safe from predation. Others lie on the sea floor or attach themselves to rocks or other hard surfaces. Some bivalves, such as the scallops and file shells, can swim. The shipworms bore into wood, clay, or stone and live inside these substances. The shell of a bivalve is composed of calcium carbonate, and consists of two, usually similar, parts called valves. These are joined together along one edge the hinge line by a flexible ligament that, usually in conjunction with interlocking teeth on each of the valves, forms the hinge. Trimble Business Center Crack Internet. This arrangement allows the shell to be opened and closed without the two halves detaching. The shell is typically bilaterally symmetrical, with the hinge lying in the sagittal plane. Adult shell sizes of bivalves vary from fractions of a millimetre to over a metre in length, but the majority of species do not exceed 1. Bivalves have long been a part of the diet of coastal and riparian human populations. Angels Singing Sound Effect. Oysters were cultured in ponds by the Romans, and mariculture has more recently become an important source of bivalves for food. Quarters a pa i n t a n d d c o r s p e c i a l i n t e r e s t p u b l i c at i o n. Modern knowledge of molluscan reproductive cycles has led to the development of hatcheries and new culture techniques. A better understanding of the potential hazards of eating raw or undercooked shellfish has led to improved storage and processing. Pearl oysters the common name of two very different families in salt water and fresh water are the most common source of natural pearls. The shells of bivalves are used in craftwork, and the manufacture of jewellery and buttons. Bivalves have also been used in the biocontrol of pollution. Check If Flash Is Installed Html. Bivalves appear in the fossil record first in the early Cambrian more than 5. The total number of living species is about 9,2. These species are placed within 1,2. Marine bivalves including brackish water and estuarine species represent about 8,0. The largest recent marine families are the Veneridae, with more than 6. Tellinidae and Lucinidae, each with over 5. The freshwater bivalves include seven families, the largest of which are the Unionidae, with about 7. EtymologyeditThe taxonomic term Bivalvia was first used by Linnaeus in the 1. Systema Naturae in 1. More recently, the class was known as Pelecypoda, meaning axe foot based on the shape of the foot of the animal when extended. The name bivalve is derived from the Latinbis, meaning two, and valvae, meaning leaves of a door. Paired shells have evolved independently several times among animals that are not bivalves other animals with paired valves include certain gastropods small sea snails in the family Juliidae,5 members of the phylum Brachiopoda6 and the minute crustaceans known as ostracods7 and conchostrachans. Anatomyedit. Drawing of freshwater pearl mussel Margaritifera margaritifera anatomy 1 posterior adductor, 2 anterior adductor, 3 outer left gill demibranch, 4 inner left gill demibranch, 5 excurrent siphon, 6 incurrent siphon, 7 foot, 8 teeth, 9 hinge, 1. Interior of the left valve of a venerid. Bivalves vary greatly in overall shape. Some, such as the cockles, have shells that are nearly globular cockles can jump by bending and straightening their foot. Others, such as the razor clams, are burrowing specialists with elongated shells and a powerful foot adapted for rapid digging. The shipworms, in the family Teredinidae have greatly elongated bodies, but their shell valves are much reduced and restricted to the anterior end of the body, where they function as scraping organs that permit the animal to dig tunnels through wood. Mantle and shelleditNear the hinge of the shell is the umbo, often a rounded, knob like protuberance usually surrounding the beak. The umbo generally and the beak specifically represent the oldest portion of the shell, with extra material gradually being laid down along the margins on the opposite sides. The hinge point or line is the dorsal region of the shell, and the lower, curved margin is the ventral region. The anterior or front of the shell is where the byssus when present and foot are located, and the posterior of the shell is where the siphons are located. With the umbones hinge uppermost and with the anterior edge of the animal towards the viewers left, the valve facing the viewer is the left valve and the opposing valve the right. In all molluscs, the mantle forms a thin membrane that covers the animals body and extends out from it in flaps or lobes. In bivalves, the mantle lobes secrete the valves, and the mantle crest secretes the whole hinge mechanism consisting of ligament, byssus threads where present, and teeth. Visible on the inside of most empty bivalve valves is a shiny curved line that runs more or less parallel to the outer margin of the shell and often connects the two adductor muscle scars if the animal had two adductor muscles. This line known as the pallial line exists because, parallel to the opening edge of the bivalves shell, the mantle is attached to the shell by a continuous narrow row of minute mantle retractor muscles. The function of these small muscles is to pull the loose edge of the mantle up out of harms way when this is necessary because of minor predation attempts. In many bivalves, the mantle edges fuse at the posterior end of the shell to form two siphons, through one of which water is inhaled, and the other expelled, for respiration and suspension feeding. Often, a pocket like space occurs into which the siphons fit when they are retracted. This is visible on the inside of the valve as an indentation on the pallial line which is known as the pallial sinus. The shell is composed of two calcareous valves held together by a ligament. The valves are made of either calcite, as is the case in oysters, or both calcite and aragonite. Sometimes, the aragonite forms an inner, nacreous layer, as is the case in the order Pterioida. In other taxa, alternate layers of calcite and aragonite are laid down. The ligament and byssus, if calcified, are composed of aragonite. The outermost layer of the shell is the periostracum, a skin like layer which is composed of a conchiolin. The periostracum is secreted in the groove between the outer and middle layers of the mantle, and is usually olive or brown in colour and easily abraded. The outer surface of the valves is often sculpted, with clams often having concentric striations, scallops having radial ribs and oysters a latticework of irregular markings. The shell is added to in two ways the valves grow larger when more material is secreted by the mantle at the margin of the shell, and the valves themselves thicken gradually throughout the animals life as more calcareous matter is secreted by the mantle lobes.