Clam

Facts about Clams, "Scientific name for Clam is Mercenaria mercenaria". A Clam is a variety of mollusk that belongs to the Bivalvia class. There are, marine and freshwater "Clam" varieties, varying in size from those that even as matures are almost microscopic to others, like the Giant Clam, which has a body mass of 440 pounds (200 kg). They have the lifespan varying according to the species. Clams do not posses heads and nearly all are blind, but some clam varieties, like the scallops, include rudimentary eyes. Though the Clam is a common food item, several species of Clam are very small to be used as food, and not all clam species are considered edible. However, all clams include two calcareous valves or shells, and all varieties of clams are filter feeders.

A Fact a Clam is a invertebrate, they do not have a spinal column. There are in excess of 100,000 types of species in the Mollusca category, and the Clam is also called shellfish. The word shellfish comprises members of the mollusk category and the crustacean subcategory, and Crustaceans, such as Clams, lobsters and shrimp and they are actually more associated with insects than to Clams.

Features

The shell of a Clam is composed of two equal valves, which are attached by a ligament and a hinge joint that can be internal or external. The ligament offers tension to get the valves spaced out, whereas a few adductor muscles can contract to shut the valves. Clams also include a heart, kidneys, a mouth, a nervous system, a stomach, and an anus. Many varieties of Clam have a siphon.

Actually, Clams live in the sand upturned. The Clam have a mouth located at the anterior end or adjacent to their foot. The anus of the Clam is at the posterior end or top, where waste is secreted.

Some mollusks or shellfish only have a single shell, like snails. Soft shell Clams include two shells so they are acknowledged as bivalve mollusks. Other bivalves include oysters, scallops, mussels and the quahog or the hard shell Clam.

In some countries the Clam is among the most common names of different species of sea bivalve Mollusk, but it is not employed as a word, covering either palatable Clams that burrow or generally bivalves. Many palatable marine bivalve Clam varieties live buried in the mud or sand and respire through siphons, which arrive at the surface. In some countries, the Clams are gathered by excavating the land.

Lifecycle

Infant Clams set up their lives as little free swimming larva. They can be easily swept away by ocean currents, eaten by fish, or stranded on the seashore. Only about 1/10th of 1 percent of all larvae in the sea survive to become mature Clams. Following 4 to 6 weeks of swimming, the juvenile Clams settle and fasten themselves to the seaweed or sea bottom by means of slim byssal threads. After four months, the byssal threads will disappear and the juvenile Clams with heavier shells are stirred in the direction of the intertidal region by the action of sea wave. They are put down here and allow burrowing into the mud or sand. The intertidal region is also a hard place for a Clam to exist. The major predators of clams include, starfish, horseshoe crabs, whelks, moon snails, green crabs, humans and seagulls.

The lifespan of Clams ranges from 1 year to 500 years, according to their variety.