Sea Spider - the mysterious inhabitant of the depths

Sea spiders are often called multicolored animals. They refer to the Helitserov class, the type of these creatures is the Arthropods. It is also permissible classification according to which the term "Helicer" is defined as a subtype from which the marine spiders are separated into a separate class. There are several other scientific names for this class - Pantopods, Piknonids and others.

Some general information

The concept of "sea spider" includes more than 1300 different species from a dozen families. They live in the seas around the world. You can meet marine arthropods at different depths. Some species prefer the lower littoral (tidal part of the shore), others descend to the abyssal (deep zone). In saline and slightly saline waters, the multiculus are much more common than in desalinated internal seas. In the coastal areas, spiders settle in thickets of algae and on the ground.

Deep-sea and littoral species of spiders differ in the structure of the body, and in size. In deep layers of water the marine spider will be larger, it has much longer and thinner legs, on which there may be long hairs. These devices reduce the immersion speed. A spider does not just float, but it seems to float in the water. To sink to the bottom, it is compact enough for him to fold his long limbs under the calf.

Coastal forms are more compact. Their legs are thicker and shorter, but they have developed bumps and thorns, necessary for hunting and protection.

Features of the structure

Any marine spider, both deep-sea and coastal species, has a typical structure. The body is divided into two (department). Their name is segmented prosoma and non-segmented opisome. Millet is characterized by a cylindrical or disk-like shape.

The body of the marine spiders has less limbs and is covered with a chitinous cuticle. There is a division into the cephalothorax and abdomen (is rudimentary). In the cephalothorax from 7 to 9 segments, 4 of them fused together. The fused part of the cephalothorax is called the head segment. The remaining segments can be either fused or dissected. In front of the head segment is a proboscis cylindrical or ovoid. On the lateral parts of the trunk are fixed two pairs of limbs: chelifory and palp. On the ventral side of the head part the third pair of limbs (ten-segmented egg-bearing legs) is fixed. One of the features of the structure of marine spiders is that the 3 front pairs of legs do not reach the ground and do not participate in walking.

The walking legs of a marine spider are fixed on the lateral processes of the head segment of the trunk. Most often there are 4 pairs, but some representatives have 5-6 pairs.

Digestive system

The sea spider has a digestive system in the form of a slightly differentiated through tube with diverticula. Diverticulum in this case is a process of the intestine, which comes into every leg. Digestion in these arthropods is combined. Joint and intracellular form are used together.

Ration

It is not hard to guess what sea spiders eat. Most of them are predators. In their diet, sedentary and inactive invertebrates. These can be polychaetes, bryozoans, infusorians, sea anemones, coelenterates and nudibranchs, small echinoderm starfish. The extraction is held by claws on chelifory. They also come off pieces of food and go into the mouth.

Gigantomania

Not so long ago a giant sea spider was found in the waters of the Antarctic. Studying the individual, scientists drew attention to a mysterious phenomenon, which was called polar gigantism. For some reason, not yet known, the icy waters of Antarctica turn ordinary species of marine spiders into giants. Perhaps, for the increased growth corresponds to the amount of oxygen, which in cold water is more than in warm water.

It has been established that not only spiders, but also some mollusks, crustaceans and echinoderms, suffer from gigantomania in the Arctic waters. Studies continue.

«Starfish and spider»

Do you think we will continue to discuss the structure and life of marine animals? But you are wrong! In this section, we'll talk about an exciting book that explains the success principle of various companies and organizations. Some of them are traditional, like spiders: their legs grow from the trunk, there is a head and eyes. They can function, having lost a part of a leg or having lost an eye, but having remained without a head - will die.

The starfish is another matter, although its body parts look ordinary, but they have absolutely different functions: the head and the brain have no head and brain at all, and the main organs are repeated in each limb. Moreover, if the limb is cut off from the star, it will be restored. Even if you cut the sea beauty into several parts, it will not die, and after a while the halves will become independent animals. In fact, with the example of this unique animal, companies that function like decentralized networks can be considered.

The book "Starfish and the Spider" is a vivid example of what is reasonable in nature and many laws of development are useful in other areas of human activity.