Oyster is a name used to refer to different species of clams which stand out for the presence of a shell divided into two valves, thus being part of the group of bivalve molluscs. In this group, in addition to oysters, there are mussels, clams, cockles, scallops, and lambretas.
Very usedThes at food, oysters are commonly eaten raw. Its consumption can be harmful in some situations, since these animals can retain it in their bodies. disease-causing microorganisms and harmful chemical compounds if they grow in water contaminated.
Read too:Classification of molluscs — animals that have seven distinct classes
oyster summary
Oysters are molluscs from the bivalves group that stand out for having a shell divided into two valves.
They feed through filtration.
They are cultivated on a large scale for human consumption.
Some oysters are responsible for forming pearls, materials of great economic value.
What are oysters?
oysters are molluscs from the bivalve group, that is, they have a shell divided into two valves. Oyster valves are joined by a ligament, and the opening of the valves is controlled by the adductor muscle, which is very strong. The shells are basically formed by calcium carbonate.
Despite their appearance, oysters are complex animals that have several organs. They have a complete digestive system and breathe through gills. It is worth noting that the gills are structures used for breathing and also for capturing food.
Oysters are fed by filtration. Filaments present in the gills allow the capture of food particles present in the water. These particles are then taken to the mouth, and the larger particles are eliminated. Before the mouth, there are labial palps, which act by selecting food.
Another important part of oysters is the mantle, which covers all of its soft parts, with the exception of the adductor muscle, which is its most external organ. The mantle is responsible for secreting the material used to build the valves and ensuring their growth. It's also the cloak The responsible forform the pearls.
Some oysters have separate sexes, while others are hermaphrodites. There are even species that can change sex, presenting an active male or female phase each year. Oysters are animals that have indirect development, being observed the formation of different larval stages before maturation into an adult individual.
Video lesson about molluscs
oyster feeding
As highlighted earlier, oysters are organisms that feed through filtration. Water enters your body when the valves open and passes through the gills, which filter what will be consumed. Part of your diet phytoplankton, microorganisms such as bacteria and fungi and small pieces of decaying animals and plants.
Economic importance of oysters
Oysters are animals that have great economic importance, being, for example, used in human food. this mollusc is much appreciated in cooking, often eaten raw.
In addition to food, oysters are also important to jewelry stores around the world. In this case, we are talking about pearl oysters, that is, the species capable of forming pearls, a material of great economic importance that has been admired since the time of ancient civilizations.
How are pearls formed?
the pearls are produced in so-called pearl oysters in response to some irritation caused by external agents entering the shell—a grain of sand, for example. In response to this irritation, the oyster begins to produce nacre, or mother-of-pearl, around the foreign body, forming what we know as a pearl.
These limestone concretions can be found in oysters that are in the natural environment, but they can also be cultivated. In order to guarantee the production of pearls, human beings introduce specific elements into pearl oysters. The oysters then begin the deposition of nacre, giving rise to a pearl obtained in a cultured way. The main regions that grow pearls are Japan, Australia and French Polynesia.
Read too: Octopuses — cephalopod molluscs that stand out for their impressive intelligence
Can oysters be bad for your health?
Unfortunately, the Oyster consumption can, yes, be harmful to health. When we consume raw food, we are subject, for example, to the development of infections by viruses and bacteria and contamination by pesticides or heavy metals.
THE problem is related to where the oysters are grown. If the waters are contaminated, the oysters can be too. It is worth noting that oysters can accumulate toxins in their body, so an oyster can store a lot of toxic substances in its body over time. One of the solutions to minimize this problem is to prioritize the consumption of cooked oysters, a measure that avoids contamination by some virus and bacteria (but does not eliminate, for example, heavy metals).
By Vanessa Sardinha dos Santos
Biology teacher
