Sea anemones are common in the coastal waters of all seas of the world. Most of these animals, varied in shape and color, live on the coral reefs of the tropical zone.
Type - CoelenteratesClass - Hydroid
Family - Actiniaria
Basic data:
DIMENSIONS
Length: from a few centimeters to a meter and even more in diameter.
REPRODUCTION
Asexual: division or budding.
Sexual: by releasing eggs and sperm into the water where free-swimming larvae develop or by internal fertilization.
LIFESTYLE
Habits: Some individuals lead a sedentary lifestyle on the seabed or other solid base.
Food: depending on the species, from plankton to medium-sized fish.
RELATED SPECIES
Sea anemones, together with corals, belong to the hydroid class, which unites about 6,500 species.
Brightly colored sea anemones with thin tentacles are one of the most beautiful marine inhabitants. For careless fish and other small sea animals that, through their carelessness, ended up very close, the embrace of the sea anemone’s burning tentacles means inevitable death.
FOOD
Sea anemones do not feed on plant or animal food. They capture food using tentacles. Small species reveal tentacles that are overgrown with small hairs. The movement of water caused by the influx brings microorganisms into the mouth. Large species grab fish and crustaceans, which they kill with the poison of miserable cells. Sea anemone has peculiar organs. The muscular pharynx leads from the oral opening to the gastric cavity. When food enters it, digestive juice begins to secrete from the openings of the glands. Then the nutrients enter the tissues.
DESCRIPTION OF ANEMONE
Sea anemones are a group of soft-bodied animals that are associated with polyps. Sea anemones and corals belong to the class of coral polyps. Like all other coelenterates, they have a very simple body structure. It is based on one outer and one inner layer of cells. The inner layer, or endoderm, limits the gastric cavity of the body, which has one opening. Through it, the sea anemone receives food and excretes waste. The outer layer, or ectoderm, consists of a large number of thin tentacles that grow around the mouth opening located at the top of the body. The tentacles have a myriad of tiny cells that serve to protect themselves and capture prey. Sea anemones have limited mobility, so they spend their entire lives attached to the seabed, rocks and coral. The disc on the underside of the anemone's sole secretes a sticky substance (the so-called cement), which allows it to stay on the rocks despite sea currents, ebbs and flows. Anemones cannot walk, but with the help of muscle contractions they can move their tentacles.
REPRODUCTION
Sea anemones can reproduce in several ways. They rarely reproduce by budding. More often, sea anemones are divided into several parts. In other species, part of the sole is separated, from which a new sea anemone grows. Some reproduce sexually. There are individuals that, being hermaphrodites, secrete both eggs and sperm. Other species are dioecious. Eggs and sperm are released in huge quantities into the water, where fertilization occurs. In this case, larvae hatch from fertilized eggs, which then settle to the bottom and develop to the size of adult organisms.
FEATURES OF THE DEVICE
Sea anemones are one of the best examples of animal symbiosis, which brings mutual benefit to two organisms, which often belong to different systematic types. Sea anemones are armed with stinging cells that can spray paralyzing poison. Some types of sea anemones often stick to the shell of a hermit crab. The hermit crab, with the help of sea anemones, protects itself from enemies who are scared away by the burning tentacles of the sea anemone, and it, in turn, feeds on the remains of its food. Numerous species of small coral fish live among the tentacles of sea anemones. The most famous of them is the clown fish. These fish protect their bodies from the pathetic tentacles of sea anemones with a layer of mucus. The coexistence of clownfish and sea anemones benefits both sides: the sea anemones provide the fish with reliable shelter, and in exchange they feed very brave hunters. DID YOU KNOW THAT...
- Some sea anemones dig holes in bottom sandy sediments or in sand, and there they wait for prey.
- Sea anemones of the genus Tealia are difficult to notice. They are perfectly camouflaged, covering themselves with sand and fragments of shells.
- Sea anemones are not always small. Species living off the coast of Australia can be more than a meter in diameter.
- From an evolutionary point of view, sea anemones are very primitive. They do not have a brain, and the nerve fibers make up a network of sea anemones that connect the sense organs directly to the muscles.
- The scientific name of some sea anemones - Anemonia - comes from the name of the anemone flower.
WATCHING ANEMONE
Several species of sea anemones live on the coast of the Baltic and North Seas. Very common are sea anemones of the genus Tealia, small green or brown sea anemones that live in the tidal zone. At high tide you can see their tentacles open. The largest sea anemones are found only at great depths. It has many delicate pink or white tentacles. In the Black Sea, you can mainly see the reddish-brown or greenish horse anemone (Actinia equina), which is attached to the stones.CHARACTERISTIC FEATURES OF ANEMONES
Sole: the underside of the body secretes a cement-like substance with which sea anemones attach to the soil.Tentacles: they grab prey and bring it to the mouth; have stinging cells.
Mouth opening: contains microscopic hairs. Thanks to them, water circulates around the body.
Slime: needed to catch prey.
PLACES OF ACCOMMODATION
Sea anemones live in almost all seas of the world, most often in tropical waters.
PRESERVATION
The sea anemone Nematostella vectensis, which lives in a salty environment, is rare in Europe today due to drainage and pollution of waters. Some tropical species are at risk of extinction due to the destruction of coral reefs.
sea anemone– lat. Actiniaria, a member of the phylum Coelenterata, belongs to the class Coral Polyps. Anemones or sea anemones are solitary invertebrate animals.
Structure
Sea anemones have a large number of smooth tentacles. The number of tentacles is a multiple of six. The number of septa of the gastrovascular cavity is also a multiple of six. The appearance of tentacles occurs gradually. In sea anemones, many planes of symmetry can be drawn, with the presence of a large number of tentacles and partitions.
Animal characteristics:
Height: the average height of sea anemones is 2 – 4 cm.
Diameter: The average diameter of sea anemones is 3 – 7 cm.
Color: Sea anemones come in colorful shapes of different colors, mostly red and green, less often brown. Colorless sea anemones are also found.
Movement and nutrition
Movement is very slow and is carried out thanks to the muscular sole. Sea anemones are able to settle on the shells of hermit crabs and live in symbiosis with them. Cancer plays the role of a vehicle. They mainly feed on mollusks, crayfish, small fish and other marine invertebrates, therefore sea anemones are predatory animals.
Reproduction and habitat
Sea anemones are dioecious animals. The formation of the gonads occurs in the septa or tentacles. Sea anemones are found in the northern seas, and they can also be seen in the Black Sea.
Sources:
B.N. Orlov - Poisonous animals and plants of the USSR, 1990.
About animals included in the order Actiniaria. The name of the animals comes from the name of an earthly flower, anemone.
If you check the classification, sea anemones are included in the class Anthozoa, a phylum of cnidarians and a subclass of six-rayed corals. This animal is known to the world because of its symbiotic relationship with fish.
Sea anemones benefit from their association with fish - improved gas exchange and nutrition (food that remains after the fish eat).
The same symbiosis has developed between sea anemones and crabs of the genus Lybia. Boxer crabs use the stinging polyps of sea anemones to protect themselves from predators. The crabs pick up sea anemones and hold them as a shield. Anemones, in turn, thanks to crabs gain mobility, because they cannot move independently.
Here are some interesting facts about sea anemone:
Sea anemones, like all other cnidarians, have mesoglea in their body - a jelly-like substance. Anemones have a close relationship with corals, hydra and jellyfish.
Sea anemones can decorate any aquarium. For commercial purposes, sea anemones are considered as aquarium collection. Thus, the sea anemone trade is increasing.
These sea creatures have an amazing range of color diversity. Their vitreous bodies are always bright and delicate.
Sea anemone size.
The diameter can reach 1.8 - 3 cm. The largest sea anemones have a span of 2 meters. The smallest ones barely reach 4 mm.
The sea anemone's mouth functions like an anus. Capture function and prey catching. The location of the mouth is the center of the disc cavity. And several tentacles located around the mouth.
Sea anemones are harmless and harmless animals. The sea anemone is not dangerous to humans. However, some sea anemone species have a toxin that can cause burns to humans.
Sea anemones feed on fish, shellfish and small sea animals. Peaceful sea anemones are calm individuals: they eat everything that floats in the water. However, they distinguish between edible food and inedible food.
- Next to sea anemones live those fish and shellfish that are insensitive to their poison.
- For large and predatory fish, sea anemones serve as a place of camouflage and shelter.
This animal, the sea anemone, has a completely different way of life from other cnidarians. They have the disadvantage of free swimming, as for example jellyfish do. They differ from corals in that they do not live in colonies or groups, but individually - they prefer to live alone.
Life cycle of sea anemone. The polyp arises from Planula after the egg, fertilized by sperm, begins its division.
Asexual reproduction is also characteristic of sea anemones. In some species of sea anemones, division is the result
asexual reproduction.
Most sea anemones live in one place permanently. However, they may move to another place if it is not suitable for them to live in. They move if predators harass them or the location encounters prolonged dryness. To get to a new place they use crawling-like movements.
Sea anemone can be eaten. It is used as a delicacy in southwestern Spain and southern Italy.
Sea anemones are often served battered or marinated in vinegar.
The animal sea anemone really looks like a flower. They were called anemones, but to some it resembles an aster. Explorers of the deep sea have counted one and a half thousand different species of anemones.
When cut into pieces, sea anemones demonstrate their remarkable ability to reproduce and regenerate.
In one row, all tentacles of an anemone are identical in color, structure and length. however, they may differ from row to row.
Sea anemones are large coral polyps that, unlike other corals, have a soft body. Sea anemones belong to a separate class of coral polyps, and they are also related to jellyfish. They are also called sea anemones because they have such a beautiful appearance that they look like flowers.
Features of the appearance of sea anemones
The body consists of a cylindrical leg and a bunch of tentacles. The leg consists of circular and longitudinal muscles, thanks to which the sea anemone can stretch, shorten and bend. At the bottom of the leg there is a sole or pedal disc.
Mucus is released from the sea anemone's leg, which hardens, and the sea anemone sticks to the substrate. Other sea anemones have wide legs, with their help they cling, like an anchor, to loose soil, and the sole with a bladder acts as a fin. These types of sea anemones swim upside down.
At the upper end of the body is an oral disc, which surrounds a row or rows of tentacles. In one row the tentacles are the same, but in different rows they may differ in color and size. The tentacles are equipped with stinging cells, from which thin poisonous threads fly out. The mouth opening may be oval or round in shape.
Sea anemones are fairly primitive creatures that do not have complex sensory organs. The anemone's unequal system consists of a group of sensory cells located on the sole, base of the tentacles and around the mouth opening. These nerve cells respond to various stimuli, for example, cells near the mouth are able to distinguish substances, but do not respond to mechanical influence, and cells on the sole do not respond to chemical influence, but are sensitive to mechanical influence.
Most sea anemones have a naked body, but sea trumpet anemones have a chitinous cover, their leg looks like a tube, which is why they are called “tubular”. The bodies of some sea anemones are covered with grains of sand and various building materials, which make the cover more durable.
The color is so diverse that even representatives of the same species can have different shades. Sea anemones can be all the colors of the rainbow: pink, red, green, orange, white and the like. Often the edges of the tentacles have a contrasting color. The body sizes of anemones vary over a wide range.
The body height of the smallest one, gonactinia, is 2-3 mm, the largest is the carpet anemone, with a diameter of up to 1.5 meters, and the height of the metridium sea anemone reaches 1 meter.
Distribution and habitats of sea anemones
Sea anemones live in all oceans and seas. Most of these animals are concentrated in subtropical and tropical zones, but they are also found in the polar regions. For example, in the seas of the Arctic Ocean lives the sea pink or the senile metridium.
The habitats are quite diverse: from the depths of the ocean to the surf zone. Few species of sea anemones live at ocean depths of more than 1000 meters. Although sea anemones are mostly marine animals, certain species can live in fresh water. There are 4 species of sea anemones in the Black Sea, one species lives in the Sea of Azov.
Anemone lifestyle
Anemones that live in shallow water often have microscopic algae in their tentacles, which gives them a green tint and supplies them with nutrients. These sea anemones live in illuminated places and are active mainly during the day, as they depend on the photosynthesis of algae. And certain species cannot tolerate light at all. Sea anemones that live in the tidal zone have a clear diurnal regime, which is associated with the time of drying and flooding of the territory.
All sea anemones can be divided into 3 types according to their lifestyle: swimming, sessile and burrowing. Most sea anemones are sessile, the burrowing ones include the genera Haloclava, Edwardsia and Peachia, and only the genus Minyas is swimming.
Sea anemones are attached to the bottom using the so-called “sole”. Sedentary sea anemones, contrary to their name, are capable of moving slowly. As a rule, they begin to move if something does not suit them, for example, lighting or lack of food. Sea anemones move in several ways. Some species arch their body and attach themselves to the ground with their oral disc, then tear off their leg and move it to a new place. Sessile jellyfish move in a similar way. Other species move their sole, alternately tearing off sections of it from the ground. And the third way is that sea anemones lie on their sides and crawl like worms, while different parts of the leg contract.
In fact, burrowing sea anemones do not burrow that often. They sit most of their lives, and they are called burrowers because they can burrow into the ground, and only the corolla of the tentacle remains visible from the outside. In order to dig a hole, the sea anemone acts in a rather interesting way: it takes water into the oral cavity, and alternately pumps it to one end of the body, and then to the other, so it goes deeper, like a worm, into the ground.
Sessile small gonactinia is sometimes capable of swimming; during swimming, it rhythmically moves its tentacles, its movements are similar to contraction of the dome. Floating species float passively on the water with the help of pneumocystis, and move with the help of the current.
Relationships between sea anemones and other marine inhabitants
Sea anemones lead a solitary lifestyle, but if conditions are favorable, then these polyps unite in colonies, forming beautiful flowering gardens. Basically, sea anemones do not show interest in their relatives, but some of them have a quarrelsome disposition. When these anemones touch a relative, they attack it with stinging cells, which cause tissue necrosis.
But sea anemones often get along well with other species of animals. The most striking example of symbiosis is the life of sea anemones and clown fish. The fish take care of the polyps, clearing them of food debris and various debris, and the sea anemones eat the remains of the clown fish’s prey. And shrimp often find shelter from enemies and food in the tentacles of sea anemones.
Sea anemones are beneficial organisms. They live in tropical and subtropical waters. The relationship between adamsia sea anemones and hermit crabs is even better established. Only young Adamsia live independently, and then hermit crabs find them and attach them to their shells. In this case, the sea anemone is attached with its oral disc forward, thanks to which it gets food particles from the soil churned up by cancer. And sea anemone protects crayfish from enemies. Moreover, when a crayfish changes its home, it transfers the sea anemone to a new shell. If the cancer has not found its sea anemone, it tries to take it away from its fellow.
Feeding sea anemones
Some sea anemones send everything that touches their tentacles into the oral cavity, even pebbles and other inedible objects, while others spit out what cannot be eaten.
Polyps feed on various animal foods. Some species filter water and extract organic debris from it, while others hunt larger prey - small fish. For the most part, sea anemones feed on algae.
Anemone reproduction
Reproduction in sea anemones can occur sexually and asexually. Asexual reproduction occurs due to longitudinal division, in this case two individuals are produced from one individual. This method of reproduction is found in the most primitive sea anemones, gonactinia. A mouth is formed in the middle of the leg of these sea anemones, after which the animal splits into two independent organisms. Since sea anemones are capable of asexual reproduction, they have a high ability to regenerate tissue: sea anemones quickly restore lost body parts.
Most sea anemones are dioecious. But there are no differences between male and female sea anemones. In certain species of sea anemones, both female and male reproductive cells can simultaneously form.
The process of fertilization in sea anemones can occur in the gastric cavity or in the external environment.
In the first week of life, anemone larvae move freely in the water, due to which they are carried over long distances by the current. In some species, larvae develop in special pockets that are located on the bodies of the mother.
The sea anemone received its second name - sea anemone - for its extraordinary beauty. This sea creature really does look like a beautiful flower. Unlike other coral polyps, the sea anemone has a soft body. According to the biological classification, sea anemones are a type of coelenterates, a class of coral polyps. They are closely related to jellyfish.
The sea anemone has a soft body compared to other corals.
Description of sea anemone
To determine whether an anemone is an animal or a plant, it is necessary to study the features of its structure. Sea anemone belongs to the animal kingdom. Its body has a cylindrical shape. On top it is decorated with a corolla of tentacles.
External features
Sea anemones come in a variety of colors. In nature there are varieties of all colors and shades. Many varieties have contrasting tentacle colors, which makes these animals even more attractive.
The sizes of these coelenterates are also strikingly diverse:
- the height of the gonactinium does not exceed 3 mm;
- the diameter of the carpet anemone reaches 1.5 m;
- The height of the Metridium salami species can be up to 1 m.
Body structure
The main part of the body - the leg - consists of muscles that are located in a ring and longitudinally. Thanks to the contractions of these muscles, the polyp can bend and change its length. On the lower part of the leg there is a so-called sole. Its surface is structured differently in different species. Some “root” in loose soil with the help of their soles, while others secrete a special substance with which they attach to hard surfaces. In the genus Minyas, the sole is equipped with a pneumocystis - a special bladder that acts as a float and allows the sole to float upward.
The muscle fibers of the leg are surrounded by the intercellular substance mesoglea, which has a dense cartilaginous consistency and gives the body elasticity.
On the upper part of the body there is an oral disc, around which tentacles are located in several rows. In one row all the tentacles are the same, but in different rows they can differ significantly in appearance and structure. Each tentacle is equipped with stinging cells that release thin poisonous threads.
The oral disc leads into the pharynx, and from there a passage opens into the gastric cavity - a primitive resemblance to the stomach. The nervous system of the sea anemone is very simple, it is represented by clusters of sensory neurons around the oral disc and in the sole area:
- nerve cells around the sole react only to mechanical impact;
- accumulations around the mouth opening and tentacles distinguish the chemical composition of the substances.
Habitats
Sea anemone is a coelenterate organism distributed throughout the world. Most species can be found in tropical latitudes, but some species live even in the polar regions, where the ambient temperature is very low. The species Metridium, or sea pink, lives in the Arctic Ocean.
The depth of the animal’s habitat is also striking in its diversity. Sea anemone can live both in the surf zone, where it falls on land at low tide, and in the very depths of the seas and oceans. Some species have adapted to survive at depths of more than 1000 meters. In the waters of the Black Sea, 4 species of these polyps were found, and in the Sea of Azov - 1 species.
Shallow-water inhabitants often rely on photosynthesis as microscopic algae take up residence in their tentacles. These species are common in places with good lighting and are active during daylight hours.
Other varieties, on the contrary, do not like bright light and tend to go deeper.
Lifestyle and nutrition
Sea anemone feeds on organic food. These polyps can catch and perceive their prey in different ways:
- some species swallow everything, including small pebbles and debris;
- some sea anemones throw out all the inedible objects that they come across;
- the largest and most predatory ones catch and kill small fish that happen to be nearby;
- some polyps live in symbiosis with algae and feed on them.
A “hungry” sea anemone opens its tentacle-rays wide and catches everything that floats past it. After the sea anemone has had enough, it rolls its tentacles into a ball and hides them. The same reaction is observed when it dries out or when danger approaches.
All sea anemones are usually divided into three varieties:
- sessile;
- floating;
- burrowing.
Sessile species are so named rather arbitrarily because they are able to move slowly. Polyps begin to move when they have little food, too little or too much light. Movement can be carried out in several ways:
- “somersaults” - when sea anemones stick to the ground with their mouth and tear off the leg, moving it to another place;
- alternately tearing off one or the other part of the sole from the soil;
- crawling, contracting different muscles of the body.
Burrowing sea anemones sit most of the time, buried in the ground so that only the corolla remains outside. In order to make a hole for itself, the animal takes water into the gastric cavity and pumps it, thus going deeper into the soil.
Floating species float on the water and surrender to the force of the current. They can move their tentacles rhythmically or use pneumocystis.
Polyps begin to move when they have little food, too little or too much light. Reproduction methods
Reproduction of sea anemones occurs in different ways. In the asexual method, the body of the polyp is divided longitudinally to form two individuals. The exception is Gonactinia - the most primitive species, which is divided transversely. In the middle of the polyp's stalk, a second mouth opening is formed, then two separate individuals are formed.
Some organisms reproduce by budding from the lower part of the stalk to form several new individuals.
These coelenterates are mostly dioecious, although it may be impossible to distinguish males and females from each other based on external characteristics. Sexual reproduction occurs in the following way:
- In the thickness of the intercellular substance, germ cells are formed.
- Fertilization can occur in the gastric cavity or in water.
- As a result, planulae (larvae) are formed, which are freely carried over long distances by the current.
Sea anemones can reproduce both sexually and asexually. Interaction with other organisms
Although sea anemones are a type of solitary polyp, in some situations these organisms can aggregate and form giant colonies. Most sea anemones are indifferent to their own kind, although some species can be very aggressive and quarrelsome.
Sea anemones can coexist very closely with other species of marine animals and plants. A common example is the symbiosis with the clownfish. The sea anemone “eats up” the prey after the fish, and the fish, in turn, cleans the polyp of debris and food debris.
Often small shrimps act as symbionts: they hide from enemies among the tentacles of the sea anemone and at the same time cleanse them of organic residues and debris.
Adamsia sea anemones can only live in symbiosis with hermit crabs, which attach polyps to their shells. In this case, the sea anemone is positioned in such a way that its oral disc is directed forward and food particles fall into it. Cancer, in turn, receives reliable protection from predators. By changing the shell, the hermit will transfer the sea anemone to the new “home”. If cancer somehow loses “its” polyp, it can even take it away from a relative. This existence benefits both species.
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