What is a sea sponge?
Sponges that are sold in stores and are used for washing dishes or cleaning the kitchen, not real. They are made from synthetic materials, although very similar to a real sponge and easy to use.
But these sponges appear in the sea, not in a chemical laboratory. For a long time many were convinced that they know all about sponges. It was believed that this plant, until in 1825 a man by the name of Robert Grant proved that sponges were animals!
It considered the sponge in water through a microscope. And saw trickles of water, which went in through one hole and out through another. Still, for many years, scientists did not know what kind of animal. Thought it was a tiny single-celled creatures that live together in one big colony.
We now know that sponges are the dried skeletons of marine animals belonging to the class of “porous”. This is a pretty significant group of animals. Although sponges are one of the lowest forms in the animal Kingdom, their structure is quite complicated.
Their top layer consists of flat cells, somewhat resembling a ladder. The channels formed by these cells, similar to those in other animals. They have the form of columns, each of which ends with a big “drain”. These weirs suck water into the sponge and then release it. Thus sponges produce oxygen and food (millions of little organisms, which are absorbed along with water). Waste is discharged together with the waste water. That’s why fresh sponge, which still retain water, smell bad. But it should be noted that this protects the lips, because the smell discourages other animals the desire to eat them!
In the center of the sponge is a light gel-like mass, which contains moving boxes. They are probably involved in the processes of digestion, respiration, and waste removal. Sponges may have a different shape and color. Generally they are very diverse, the most valuable kinds of sponges can be found at great depths at a distance of 80-130 km from the shore.
Despite the fact that modern industry produces a lot of substitutes for sponges from sponge rubber and foam rubber, a natural material no less. The fact that tenderness and hygroscopicity are all artificial products of this kind are much inferior to natural sponges. About 50 years ago, world production of sea sponges was equal to 300 tons per year and was estimated at about $ 4 million. More recent data on fisheries for dressing sponges are not available, their price on the world market is still high.
Sponges are among the most low-organized multicellular representatives. The porous body of the sea sponge is permeated by a network of canals, lined by flagellated cells that are driven through the channels of seawater and extract from it the food particles. The space between the channels is filled with a gelatinous mass and a prisoner in her supporting skeleton is elastic, Horny threads of the substance of spongin or needles of silica or calcium carbonate. The value is only the skeleton.
The most widely used from ancient times to the present day have a toilet sponge, the skeleton of which is devoid of mineral needles. Fishing toilet sponges is in temperate, subtropical and partly tropical seas in shallow water. The diver pulls the sponge from a rock or other substrate and placing them in a grid, which is then lifted by means of ropes to the boat. Sometimes using a dredge or iron the cat, but this way of production a lot of damaged sponges. The extracted sponge soaked in fresh water, and then perekinut long legs to separate from the skeleton into the soft tissue. Washed and dried the sponges are sorted by size, shape and softness, after which they go on sale.
The skeletons of deep-sea sponge “Venus basket” sold in Japan as jewelry and trinkets are quite expensive. To get delicate with the depth of the sponge without damaging it, you can only use special fishing gear from thin bamboo poles with hooks. To load the tackle on the bottom, its weight stones. Raised sponge hung on the branches of trees, where under the influence of rain and sun, they are cleaned from soft tissues.
How sponges eat?
Maybe it’s hard to believe, but sponges are animals! This is one of the most bizarre members of the animal world and are more like plants than animals.
There are over five thousand different species of sponges. They can be of various colors, starting with green, brown, yellow, red and orange to white. They may have a fan shape, dome, ball and socket.
Some sponges branched like trees. Other open flat masses of spongy tissue on the surface of underwater rocks, large shells and pieces of wood. Some of them are quite small, less than two centimetres in length. Others, on the contrary, large: up to a meter in height or width.
Adult sponges never move about from place to place. And despite the fact that the sponge is an animal, it will not react to your touch. Sponges have no head, no mouth. It has neither eyes, nor ears, nor any other senses. Also, the sponges no heart, stomach, muscle and nervous system. If a living sponge is cut in half, all you will see is a slimy mass with holes or channels penetrating it through and through.
Isn’t it, it doesn’t make her look like an animal? And you can perfectly understand why even scientists very long time to recognize her as an animal.
So what makes a sponge an animal? The way she eats. Sponge catch their food. She does not, like green plants, food for herself and eats small plants and animals that live in the water beside her.
How does she do it? The spongy walls resemble a sieve, or a filter that ottsezhivajut small plants and animals from the water. Water is impounded and is discharged from the sponge by using a constantly-moving little similar to hlystika filaments, called flagella. Flagellated cells capture food. Around the base of the flagella is a sticky surface, to which the food sticks. Some part of the food is digested there, and the remaining food “travelling” by sponge cells spread to other areas.