Is an actinia an animal or a plant? Description and photos of anemone

Any person who saw this amazing creature, first of all, is interested: is the anemone an animal or a plant? Many people are misled by the definition of this creature - "sea anemone": yet most people know that an anemone is a flower. Surprisingly beautiful sea inhabitants, who managed to adapt to life in the form of quite vulnerable organisms, amaze the imagination: they want to carry them away with them, protect and shelter. It's not worth it! First of all, it is not for nothing that sometimes these creatures are called "jellyfish-actinia": they are quite capable of standing, and not only for themselves. And secondly, you are unlikely to succeed in creating suitable living conditions for them. So, being at the resort, just enjoy their views and try not to swim too close to not heal after rather painful burns.

Appearance

It is the appearance of these creatures that gives rise to the age-old question: an actinia is an animal or a plant? And by the way, until the end of the 19th century, they were referred to plant species. However, science does not stand still: it was established that "sea anemones" are animals, in their structure and way of life close to jellyfish and other coelenterates, to which many biologists class marine sponges and ctenophores.

If you explain primitively, then any actinia (photo presented) - this is one solid mouth on the leg. "Petals", similar to the flower - it's the tentacles responsible for the delivery of food. Most often, the "stand" has a flat sole, which "sea anemones" are attached to a rock or hard bottom; But there are species with a pointed limb - they are stuck in the bottom like a bouquet; But there are floating varieties. Observing the behavior of these creatures, you will not begin to be puzzled: an actinia is an animal or a plant? It immediately becomes clear that she is not just an animal - she is a predator.

Anemones of the sea are not polyps

It is also mistaken to say that this is the most beautiful creature - coral. Actinia, no doubt, is very close to polyps, which form fascinating islands. However, the skeleton is not formed, and corals are the skeletons of polyps. In this case, it can not be said that the actinia is "soft", since the substance that fills its space between the cells forms a very thick layer and resembles the cartilage of vertebrates in density.

What do they eat?

Another argument in doubt, anemia - is an animal or plant - its diet. If those who are interested remember, plants feed on water (with substances dissolved in it) and what they can extract from the soil. However, sea anemones prefer a completely different menu. It includes small invertebrates and small fish (if lucky). The way to produce food is also absolutely non-viable: the tentacles paralyze the prey and pull it up to the mouth opening. Someone may object: carnivorous plants are also known . This is so, but they can not boast of a mouth and they dissolve the extraction by enzymes located directly on a leaf plate or in a flower-trap. That is, they do not have organs intended solely for digestion.

Impact on the victim

Even if we assume that the actinia is a plant, then we must seek an explanation for its mode of hunting. In every stalking cage - albeit very, very small - there is a kind of capsule in which a poison is enclosed. And from the outside there is a stinging thread with spines turned back. Visually, under a microscope, this whole device resembles a miniature harpoon. When attacking the anemone, the thread straightens, the needle pierces the body of the victim and releases the poison. Such a complex structure has no plants - they stand much lower in the evolutionary ladder and have a much simpler structure.

By the way, the stinging venom of anemia is dangerous even for such a large organism as a person. Of course, it will not lead to death, but it will provide a burning sensation with itching, and in some cases necrosis also develops. Those who regularly communicate with tender "anemones", almost all polls all have an allergy.

Famous symbiosis

I must say that most of the marine flowers lead a fixed lifestyle. However, the renewal of hunting grounds is what any actinia needs. Movement is usually carried out by means of symbionts. The most famous of them (familiar due to the Soviet touching cartoon) is a hermit crab. The most interesting thing is that this armored inhabitant of the seas himself transfers to his "shell" a deadly creature dangerous for mollusks. For a long time they peacefully coexist: the cancer carries the sea flower from place to place, actinium reflects the attacks being made against it by its natural enemies. However, everything is not so cloudless: the "leg" of the sea "flower" easily dissolves the organics, from which the carapace of the carrier is composed, after which the cancer comes to an end.

The movement of "sea anemones"

Even those actinia, which are intended by nature to "sit" in place, can move. In the end, the small inhabitants of the oceans, as they say in the people, are "not stupid than a locomotive" and eventually realize the danger of some bottom terrain. Accordingly, the ocean flowers are forced to migrate, as their hunting grounds become scanty. What in this case is the average actinia doing? Moving it slowly, but confidently. The sole is separated from the bottom, is pulled out for a small distance, fixed and tightens the rest of the body. However, small varieties (like gonaktinii) can even swim, straightening back the tentacles.

Fish-Actinarian Cooperation

I must say, ocean anemones symbiote not only with hermit crabs. They also travel on other armor (however, for carriers this usually ends equally, even in the case of small varieties). However, the sea anemones can coexist peacefully with fish. Near the Australian coast, the biggest aktiniums on the earth (their "mouth" is often not limited to one and a half meters in diameter) give shelter among their tentacles to amphipriones - very bright fish that feed the "master" with the fallen remnants of food and create additional aeration by the fins. Actinia at the same time are quite able to distinguish their friends from other fish and actively protect them from predatory encroachments.

Reproduction of actinia

Preference is given to the sexual mode, which is another proof that sea flowers are animals, not plants. However, under unfavorable conditions, they can also use budding, in which one begins to remember the delusion about "actinia - plant," and longitudinal or transverse division. This is especially true of small varieties. The same gonaktinia is used to divide transversely. It is extremely interesting to observe this: the first thing is growing a wreath of tentacles along the circumference of the body, and then it separates. The upper half grows to itself a sole, the bottom - "mouth" and one more set was shining. It is noteworthy that the second division does not wait for the end of the first, so the anemone of this species can be girded with several rings of tentacles, predicting the early appearance of several individuals.

To check, an actinia is an animal or a plant - it is possible and by own example. Marine anemones do not regard a person either as an enemy or as a prey. So when people touch, they just fold (if you do not pull them, of course). You can say they are hiding. And the rest of the actinia (photos show this) - a very beautiful and interesting creature, which is curious to even watch.