In nature, there is a unique creation,nicknamed "water bear". Very few people (with the exception of zoologists and space specialists), knowledgeable people, it amazes with its appearance and its vitality. The creature received the primary name for a clear similarity with a candy or teddy bear. True, he has six legs, and it is difficult to call a “face” cute, but otherwise can be traced clearly. A "water" bear because it is an inhabitant of this environment and cannot live (in the true sense of the word) without moisture.
History of discovery
There is reason to believe that waterSlow bears were precisely those creatures that the microscope maker van Leeuwenhuk saw back in 1702. However, the first official discovery of these unicums was in 1773, when they were described by the German pastor Goetz. Stunned by their appearance, he gave them the name kleiner wasserbär, which translates from German as a small (tiny) water bear. Microscopic creatures were studied and described in more detail by the Italian biologist Lazzaro Spallanzani, and this happened in 1776. Because of the extremely slow mobility of animals, he called them il tardigrado, as a result of which the term Tardigrada, that is, slow moving, became the official scientific name.
Water bear
The first thing to note when studyingSlowgun - the size of the animal. There are about 960 species of sea bears, and their body size varies from 0.1 to one and a half millimeters. Even the largest specimen to consider without a microscope is very difficult. Slow paces are included in the class of invertebrates, have a glassy, translucent body, visually broken into 4 segments constrictions. Due to the presence of chitinous shells and periodic molting of a water bear, they are sometimes compared with insects. Most varieties have four pairs of limbs, but one of the smallest "breeds", only one tenth of a millimeter long, is an exception: it is six-legged. Each paw ends with claws in the amount of 4-6 pieces. The last pair of legs is oriented back.
The “face” of the creature is very unusual and resemblesdust collector on the vacuum cleaner. The mouth is equipped with a kind of stylet, which the water bear pierces the shell of the food. These animals have nervous, digestive, reproductive and nervous systems, however, there are no circulatory and respiratory systems. Instead of blood, the cavity of the whole body is filled with a special fluid, and the skin breathing is slow. They have additional organs of touch in the form of a pair of appendages, and, oddly enough, the eyes, which are the pigment spots on the body in front, but not in the place that can be called the head.
The water bear is color dependent on the habitat. Hue may be in the color range of orange - scarlet or olive - dark green.
Slow paces are heterogeneous, but males are much more rare than females, therefore, there are multiple cases of parthenogenesis (reproduction in the absence of fertilization).
Тихоходки распространены по всему миру от tropics to the polar circle. However, if they can choose, they prefer wet lichens and mosses. The water bear has a passive distribution in the water bear: individuals move due to the flow of water or wind, and are also transferred to birds and animal fur.
Features of nutrition
Slow-moving water bears for the most partlive by moss, small algae and bacteria. Three oceanic species parasitize exclusively on shellfish, larger aquatic invertebrates and sea cucumbers. About one and a half tens species of water bears - frank predators, which diet includes microorganisms and roundworms; such a slug is dangerous even to her own brethren - cannibalism is an everyday matter for her.
Unkillable creature
Most water scientists are interested scientistsits vitality. These creatures are able to maintain their life and ability to reproduce in the widest range of temperatures - from absolute zero (-273 degrees) to unbearable heat at +150. They survive in a hostile environment, for example, in a hydrogen sulfide atmosphere. Radiation is also not an insurmountable barrier for survival for them: after irradiating it at a dose of 570,000 x-ray, half of the water bears survived. For reference: radiation of “only” 500 x-rays is fatal for humans. And the surviving sluggish still could give (and gave) offspring.
Cosmic stability
Most of all, the scientific community is interested inTardigrada's ability to withstand the conditions of space. In 2008, a research team led by the Swedish ecologist Ingmar Jonsson sent an experimental batch of slow-moving animals into orbit around the Earth. One group was placed in a vacuum, the second was simultaneously irradiated with radiation, two were subjected to intensive ultraviolet treatment. The subjects spent 10 days in outer space and were almost completely withered. However, upon returning to more favorable conditions, most of the microscopic creatures returned to life, retaining the ability to reproduce.
Basis of survival
Ability due to which water bearcan tolerate such a wide range of adverse conditions - the ability to fall into anabiosis by controlled anhydrobiosis. In other words, the slug dries itself, leaving a negligible amount of water in its body. In order not to lose them, the sludge forms a kind of wax shell on the surface of the body. In its dried form, the sluggishness activates additional protective functions: sugar molecules prevent cell expansion, start production of antioxidants that resist radiation and prohibit DNA destruction. When water enters the environment, the body of the sluggish starts to absorb it, and all vital functions are restored.
Natural Water Bear Enemies
Несмотря на всю живучесть, водяной медведь отнюдь is not immortal. Successfully counteracting an adverse external factor, he is rather helpless against predators who are not averse to eating. In addition to their own relatives, sluggish animals are attacked by rotifers, ticks, springtails, roundworms and earthworms, larvae of various insects and crayfish. Part of the slug cattle dies, becoming the prey of a carnivorous fungus: its hyphae interlace into loops, in which a water bear gets trapped, after which the mushroom threads grow into it. In addition, there are mushrooms, whose spores are attractive for sluggish in terms of food. However, once in the intestine of a water bear, spores germinate, using the animal as a nutrient medium.
