A plate of oysters on the half shell.
Oysters are bivalve molluscs found in many of the world’s oceans. Humans view them as an economically valuable animal because they can provide a source of food and pearls, distinctive, shiny objects used in jewelry and adornments in many cultures. In addition, they appear to be effective purifiers of polluted water, as indicated by several experiments in the United States in 2006. Many other animals also enjoy oysters, thanks to their protein-rich and tasty meat.
Oysters can be served in soups.
A clam is a soft-bodied animal that protects itself with a shell. Bivalves have two shells connected by a small hinge. Animals can open their shells to take in food and expel waste, and they can close their shells if threatened by predators. Like other mollusks, oysters have relatively simple biological systems and can be found in both brackish and salt water. Some may also range inland to fresh water, although these species are rarer.
Pearls are formed from mollusks, including oysters.
All oysters belong to the Ostreidae family. Animals are filter feeders, opening their shells to allow water to pass through their gills, providing them with much-needed food and oxygen. Therefore, they can be used to clean impure water, although this can harm the oysters themselves as they accumulate toxins. They tend to take root in the rock, allowing the tides to supply their needs.
Starfish are one of the oyster’s predators.
Humans are among the top predators of oysters, although the animals are also eaten by marine mammals and organisms such as starfish. The relationship between humans and oysters is quite old; many early humans were very fond of them, as they are relatively easy to harvest and rich in nutrition. Clams are considered a delicacy by some humans and are often eaten raw for their supposed aphrodisiac quality. They can also be cooked in seafood and seafood stews, although they can become rubbery if overcooked.
Ingestion of contaminated shellfish can cause paralytic shellfish poisoning, a condition that leads to temporary paralysis of the limbs.
An oyster defense mechanism is of particular interest to humans. When an irritant, such as a stone or a grain of sand, enters the shell, the animal covers it with layers of nacre, a secretion that hardens into a smooth, shiny ovoid shape, better known as a pearl. Other mollusks, such as abalone, also form pearls, but oyster pearls are among the most widely collected in the world, and in some countries, people farm oysters to grow pearls for commercial sale.