Type of intestinal development. Coelenterates

In this article we will consider the features of the type of intestinal. What animals do it apply to it? Why are they combined into this type? So, coelenterates - It is the living in the aqueous medium of multicellular invertebrate animals. These include jellyfish (or scamphoid), coral polyps and hydra (hydraulic). Their body, in a schematic simplification, a pouch resembling a bag, formed from the outer and inner layers of cells and is characterized by radial symmetry.

There are intestine-haired from primitive multicellular consisting of cells of two types. They live exclusively in water, both salty and fresh. Intestine variables differ in order whether they are prone to change the place of residence. Jellyfish are free, and move rather quickly, but coral polyps are attached forms that can live with colonies or one. Freshwater hydra is an intermediate form - it usually leads a sedentary lifestyle, but is capable of moving, though very slow.

Structure of intestinal

1. In the intestine-haired there is only one "entrance", that is, the mouth cavity, and there is no "output". The mouth, scribbled by tentacles, leads to the blind accomplished gastral (intestinal) cavity - Hence the name.

2. The body consists of two cell layers: etoderma (Motor cells with flagellas) and entoderms (digestive, forming floodplains). Between them lies a non-cellular layer mesoglya.

3. Diffuse nervous system Formed ukish-winged for the first time in the process of evolution. Nervous cells are chaotic arranged throughout Etoderma and with each other in contact with the process.

4. Jellyfish Nervous cells are collected in nodes - gangliaForming a nervous ring.

5. The respiratory and excretory gauge bodies do not have.

Power supply

1. Intestinal - predatory Animals. Food for them is a variety of live trifle, which a water medium is packed.

2. Coral polyps are capable of eating two types. For heterotrophone Type they capture food with their brightly colored tentacles, but conditional " autotrophs " They help to be symbiotic algae living inside polyps.

3. digest food intestine-haired as inside a garbage cavity (the so-called intra-band digestion) and in Entoderma cells ( intracellular digestion).

4. Imaginary food is sent to where he came from - through the oral cavity to the external environment.

The reproduction of intestine-pilot

1. Implemented reproduction Intestine in two ways: clever and polov. Moreover, many representatives of these two options can replace each other - alternating generations.

2. Internally, peculiar separation of floors, however, exist among them and hermaphrodites, for example, ceriant and hydraulic corals.

3. There are species with direct development, but there are also intestinal passing through lichwater stages.

The meaning of the intestinal

1. At any predator, there is its predator - intestinal carrier are food for marine inhabitants. For example, butterfly fish with pleasure essay coral polyps. Jellyfish also serve as food fishes and sea turtles. Multiple views of the jellyfish do not face and man in Asia has long been in honor of the conference, Stomolofus Meleagry and others.

2. Coral thickets - a house for a variety of living organisms. There is always food and shelter here.

3. Coral polyps filter water and thereby cleaned it.

4. Corals are involved in calcium cycle, form sedimentary rocks, fantastically beautiful coral reefs and islands.

5. From corals manufactures building materials. The product of their firing is lime.

6. Red and black corals have been used by a person as a jewelry for thousands of years.

Intestine trades are considered the first real multicellular animals. In the process of their individual development, two germinal leaves are formed - Entoderma and Etoderma. For comparison, the larvae of sponges are not formed such germ sheets. In the body of intestinal carrier, you can allocate fabrics and even organs.

Intestinal seeds were seen earlier and are being considered now in many textbooks in the rank. type. However, in modern literature of terrestrial, more and more often consider the non-systematic rank by the group and the two types are united under this title, whose representatives live in our time, is the type of stringing and type of comb. The old idea of \u200b\u200bthe intestinal sex did not include the skids. In this case, the intestinal and stringing - this is the same. The stringing attributes hydroid, scamphoid, coral polyps and some other classes. Given below the description is predominantly applied to the cutting.

All intestine water animals, most of which live in the seas and oceans. Small part dwells in freshwater reservoirs.

Estimate - radial symmetric animals. This distinguishes them from more complex organized animals with bilateral symmetry. In the case of radial (or radial) symmetry through the body, many planes can be carried out that separate it into two symmetrical halves. In the case of bilateral symmetry, only one can be plane.

The radial symmetry of the animal suggests that he is still saving food from which side to him. Such symmetry is beneficial for sitting lifestyle. The lifestyle of many intestinal carriers is such and is. However, among them there are mobile radially symmetric forms (jellyfish).

For intestinal (ardent), two vital forms are characterized - polyp and jellyfish. Polyp Leads attached lifestyle, often forms colonies, but there are single forms. Jellyfish - Mobile life form, according to the general structure of the structure, resembles a slightly blended polyp, which will turn over the mouth and tentacles down. In the life cycle of many intestinal, alternation of life forms occurs: the polyps form jellyfish, which are multiplied by sexually, after which young polyps are formed, which, having put adults, multiply by the kill (for use of the method), and form jellyfish. However, a number of seven-transfer species are represented by only one life form.

In the intestine-haired there is a tentacle surrounding mouth, who serve them for catching, capturing and premises in the mouth of food. All animals of this type are predators (food serve arthropods, single-celled, small fish, etc.). Also, the tentacles can serve as movement bodies.

In the process of evolution, a number of progressive features appeared in the structure of intestinal trap in comparison with the colonial simplest and sponges. So they had an intestinal cavity. Food is partially digested in it, and not exclusively in cells, like sponges. If the sponges have the channels and cavities just pumped the water from which the cells were captured by food particles, then in the intestinal cavity in essence turned into a digestive system.

Intestinal cavity has only one oral hole. Removing untapped food residues occurs through it.

In intestinal two cell layers - etoderma (external) and entoderma (interior). They can be considered types of fabrics. Although cell varieties are more. Between ectoderma and entoderma there is an intercellular layer mesoglyaconsisting of a centered substance. Meduse mezoglya has stronger than.

In Etoderma most skin-musical cells. there is crazy cellswhich "shoot" when protection or attack. In the intestine-haired no muscle tissue, but ectoderma cells and entoderms have muscular processeswhich are located between these layers. Their nervous system reduced and relaxation determines the agreed movement of the parts of the body of the animal and its movement in space.

Entoderma mainly make up cells responsible for digesting food as well secretoryMixing in the intestinal cavity of a substance for extracellular digestion.

The unity of the organism reactions to the irritants of the external environment is carried out thanks to the nervous system. In the intestinal transparent, unconditional reflex appears. The nervous system is diffuse (mesh). Her cells are located all over the body at the base of Etoderma. But jellyfish can observe nervous components, photosensitive organs and equilibrium organs.

Intestines can reach quite large sizes. But still, they have no respiratory organs and allocations. Twinelayer provides contact with an external environment to almost all cells, which allows them to absorb and allocate directly into the surrounding water.

In the body of intestine happiness intermediate cellscapable of sharing and turn into all other types of cells. This causes a big ability to regeneration (restoration of lost parts of the body) in these animals.

Invertebrates are ancient invertebrates, multicellular animals. The first radial creatures, which, from other living creatures, distinguishes the presence of complete symmetry. Such a structure is beneficial to the fact that the animal is still from what side the food floats to it.

They received their name, thanks to the unusual structure. They have a two-layer body, between the layers of which there is a certain cavity, called intestinal. It contains a river hole, surrounded by tentacles to capture food.

Representatives of this group have no respiratory bodies, blood circulation, as well as an excretory system. They have an unusual nervous system, the basis of which is nervous plexus (Plexus).

If we talk about the digestive system, then the intestine animals have a river hole and an intestinal cavity formed in the process of evolution. But, due to the closetness of the digestive system, undigested waste of life, they also remove through the oral cavity.

A considerable part of these marine animals uses a sexual way of reproduction. In their body there are plankton, or crawling larvae. They produce them to an external, water environment where their merger occurs. Many individuals alternate with each other (binding) and a sexual way of reproduction.

An interesting feature of the intestinal transfer is their ability to regenerate, due to the presence of special intermediate cells in the body, which can be divided and transformed into various types of cells required by the body.

In total, in the group presented, the group has about 9,000 species. Some individuals, due to their sizes (about 2 millimeters), are barely distinguishable. Others achieve more than 2 meters and have a tentacle, more than 15 meters long (Cyania's jellyfish).

All intestinal can be divided into:

• Hydroid. It feeds such a kind of both plankton and small animals. Multiplied by the kill and has the simplest structure of the body, compared with its relatives;
• Scifoid. Simply put - jellyfish;
• Corals.

Intestinal plays a rather significant role in nature. They are involved in the regulation of the number of small fish and crustaceans. Forming coral reefs around the islands, preventing the passage of ships and dangerous predators to the shores. Reefs are asylum for marine inhabitants and their food.

Separate individuals, such as jellyfish, can cause strong burns that sails themselves with the lucky.

Some species actively use in their lives and man. For example, dead corals are used as building materials and in the jewelry industry. And the special kind of jellyfish is "Ropile", the Japanese, with pleasure, eat in food.

Option 2.

Now animals are very diverse, as well as different in the structure, diet, habitats and features. But the first animals did not have any functions or properties that would allocate them among the rest of the animal world. And yet, the first changes appeared after infusories, in the type of intestinal. What do they imagine? What are their main distinguishing features? And does he carry a role for himself?

Main characteristic

Their bodies have 2 layers - ectoderma and entoderm, they are also the top and bottom layers. The upper layer consists of nervous, skin-muscular, blinking, intermediate and genital tissues. The lower layer includes digestively - muscular and glandular tissues. There is another 1 extra layer called mezoglyey. It does not have a cellular structure. Its task in connecting two main layers. Have a radiation symmetry.

The mouth is arranged in such a way that the tentacles are located around the oral cavity. It is also worth noting the presence of an intestinal cavity, hence the name of the type. Their nervous system diffusion. Nutrition or intramilly or intracellular. One of the main and most important features of intestine-grades is the ability to regenerate. Regeneration is the ability to restore tissue after a certain injury. Nobody has no regeneration to intestinal regeneration. Intestines feed on plankton, mainly, but can eat fish. Inboard themselves can also be used in food. For example, turtles.

What is the benefit of intestinal people?

Despite the fact that intestinal - is one of the first types of animals, people still use them. For example, to obtain materials for the structure or in jewelry. We use some representatives to eat. It was all a positive effect on humanity, and there is a negative one.

Jellyfish are one of the representatives of this type that can cause bores to people. If you deepen at this moment, that is, poisonous jellyfish. The most dangerous of them is considered to be jellyfish, called the sea axis. There may still be such a case that reefs consisting of corals will interfere with the ships sailing further. The same reefs, by the way, serve as a house for marine animals.

• Dike - message report

  Dicuity relate to rodent detachment and is a mammal animal. Usually, dickered in large quantities can be found in the subtropical and tropical climatic zone in countries in Africa and Asia

• Report Health and Healthy Lifestyle (Message)

  What does health mean, everyone knows. In one joke it says that health - when every day hurts elsewhere. In fact, health - when you do not hurt anything.

• Lake Seliger - message report

  In the Novgorod and Tula regions there is a unique place - Lake Seliger. In fact, the lake is not quite accurate for Seliger. Located on the Valdai hill, a complex of small lakes is connected to one large natural monument.

• Cheetah - message report

  Everyone knows that cheetahs are the fastest cats in the world. When pursuit of prey, they can develop speed for about 115 km per hour in 2 seconds. These predators live in most countries in Africa.

Vladimir - Russian city. It is part of the Golden Ring of Russia and is considered his goal. The population of the city is about 350 thousand people.

Intestine, like sponges, first appeared on Earth more than 500 million years ago. They possess multicellular organisms and most different forms. Estimate include marine anemones, jellyfish and corals.

general characteristics

The body of the intestinal happiness has a shape of a bag with a hole that is surrounded by tentacles. They can be treated up like polyps or down like jellyfish. In intestinal and sponges, a radially symmetric body, that is, parts of the body are located around the central axis.

Food

The inner cavity in the body of intestinal transparents is communicated with the surface with a single opening that serves to receive food and emissions of untapped residues. Around the hole are tentacles, which are captured, paralyzed and tighten the prey.

Habitat

Inhabitant inhabitants in warm tropical seas; Some of them are motionless lifestyles, others are free. So, hydroids can be immobile (polyps), and floating (jellyfish); The class of scamiffoids is only jellyfish, and the class of coral polyps includes only fixed forms - polyps living separately or in colonies. Intestine-haired are multicellular organisms that are characterized by a simple structure and radial symmetry. This building is very convenient for animals that are not able to move freely: and food, and enemies can appear from anywhere, so it is important to be ready for an attack or defense on any side.

The body of all intestinal carrier consists of one inner cavity communicating with the surface with the help of the hole - the walls of which perform respiratory functions, serve to receive food and remove recycled products.

The mouth is surrounded by tentacles with nettle, or blinking, cells. When a small animal concerns one of them, the tubular fiber containing a poisonous liquid is ejected out. Hundreds of such threads are sacrificed, and the tentacles pull it, paralyzed, into the oral cavity. Thus, the intestinal-haired are predators; Their prey becomes small fish and crustaceans. Due to the specifics of the body structure, there is a well masked well on the bottom and become a sudden cape for their victims.

The type of intestinal structure (the main types of two - polyps and jellyfish) during the development of the animal is able to change: the larva can be fixed, in the form of a polyp, and an adult individual - mobile, like a jellyfish; Conversely, the larva is a movable, and an adult animal is a fixed form of a polyp, like corals.

The walls of the body's body consist of two rows of cells: one external, it is called ectoderma, and another internal - entoderma. Between two rows of cells - a jelly-like layer with plenty of water.

Ektoderm makes oblong muscular cells, and entoderm - rounded. A fracturing movement characteristic of jellyfish is ensured by the activity of these two series of cells, which are stretched and compressed. Such movements allow jellyz to move forward: compression pushes water from under an umbrella outward, and the jellyfish gets a jet push as a rocket.

The remaining cells were transformed into the nervous and the grid envelop the surface of the body, endowing the jellyfish by the senses.

Intestines are divided into three large classes: hydroids, scoffoid and coral polyps.

There are 2,700 types of hydroids; They are small, multiply only by killing and there are two forms - polyps and jellyfish. Live isolated as a hydra, or in colonies, like hydrants.

The class of scamphoid includes jellyfish of bright colors with large umbrellas; They live only isolated. There are about 250 species of scamphoid: the largest representative of this class is arctic cyania, the umbrella of which in diameter is more than 2 m.

Coral polyps - the class of intestinal with the largest amount of species - 6500 species. It is found only in the form of polyps, they can be single, like acti or maritime anemones, but more often live with colonies like corals and Madporrows.

The most popular from coral polyps is a red coral - with distant antiquity known in China and Japan; In Europe, he began to be widely used for the manufacture of jewelry even before our era. For residents of Tibet in the XIII century BC, the red coral was a broken coin. In addition, various healing properties were attributed to corals at the end of the XIX century: coral powder was considered panacea from many diseases.

Views

Noble, or red, coral, meets mainly in the Mediterranean Sea at a depth of 20 to 200 m in colonies with a height of 10-14 cm. Other representatives of this species living in the Japanese Sea reaches 1 m in height and weigh about 40 kg.

Thousands of years, noble coral was used to make small ornamental products and decorations. He is found even in the burials of the IV century to our era.

We visible part of the coral is an external skeleton, very tough and fragile, formed by small polyps. They constitute branched colonies that resemble small trees, especially when they move with their tentacles, similar to colors.

Hydra lives in fresh water. Because of its six thin tentists, the length of which is six times the size of the hydra itself is six times, it is quite reminded by algae. Looking but it is difficult to imagine that this innocent animal was identified in Greek mythology with a monstrous snake about nine heads who grew again, every time they were cut off.

The structure of the jellyfish is interesting to the fact that this animal is 95% consists of waters, and organic matter is only 5% of the total mass. If a big medus is thrown into land, it completely "melts", and after a few hours there will be no anything else in the sand, except for a small wet span.

Ksenia is a very beautiful coral, similar to a tree, sparkling with his faded tentacles.

The sea feather, unlike his conorgan's relatives, the external skeleton is soft and flexible, which makes it look like an elegant goose feather. He radiates a bright blue-green color, because of what the Latin name Rennatula phosphorea received, translated into Russian meaning "phosphorus".

Anemone Vrukozo is an acting of medium-sized (about 3 cm) with a characteristic stitched leg. In case of danger, she hides his tentacles in his mouth and becomes like a solid ball.

Gorgonarian Unitella Cavolini is a very rare coral found in the Mediterranean Sea. He lives in big colonies, and its branched "crown" reaches 70 cm long. Unfortunately, the beauty of this coral attracts the attention of poachers.

In the Mediterranean Sea, you can meet the carofillu Klava - the livingly interruption of the marador with a thin transparent body.

Type of terrestrial

The type of shepherds includes lower multicellular animals, the body of which consists of two layers of cells and has a radiation symmetry. Live in marine and fresh reservoirs. Among them are free-peeling (jellyfish), seating (polyps), attached forms (hydra).

The body of the intestinal formation is formed by two layers of cells - ectoderm and entoderm, between which the mesoglya is located (non-cellular layer). Animals of this type are viewed at one end of the bag. The hole serves as a mouth, which is surrounded by a purecker. Roth leads to a blind digestive cavity (garbage cavity). Food digestion occurs both inside this cavity and individual Entoderma cells - intracellularly. Unpained food residues are highlighted through the oral hole. In the intestine-haired, the nervous system of diffuse type appears for the first time. It is represented by randomly scattered in ectoderm by nerve cells, which come into contact with their processes. Floating jellyfish occurs the concentration of nerve cells and the nervous ring is formed. The reproduction of intestinal transparents is carried out both with an intimate and sexual way. Many intestinal separation, but there are also hermaphrodites. The development of one-haired direct, and in others - with a larvae stage.

The type distinguish three classes:

1. Hydroid

2. Medusa

3. Coral polyps

Hydroid class

His representative - freshwater hydra. The body is a length of up to 7 mm, tentacles - up to several cm.

The main mass among a large number of different types of hydra cells is the coating and muscle cells, forming a coating tissue. Muscular fabric as such is absent, its role is also performed by skin-muscular cells.

In Etoderma there are cutting cells that are preferably located on the tentacles. With their help, the hydra is protected, and also delays and paralyzes production.

The nervous system is primitive, diffuse. Nervous cells (neurons) are evenly located in Mesogle. Neurons are touched by heavy, but do not form clusters. Sensitive and nerve cells provide perception of irritation and transfer it to other cells.

No respiratory system, Hydra breathe through the body surface. There is no circulatory system.

The glands of the adhesive cells are concentrated mainly in the ectoderm of the soles and tentacles. Also synthesized enzymes that contribute to digesting food.

The digestion in the hydra is occurring in a gastral cavity in two ways - intra-freeway, with the help of enzymes and intracellular. Entoderma cells are capable of phagocytosis (seizure of food particles from a gastric age). Part of the anti-organo-muscular cells of the Entoderma is equipped with flagellas in constant motion, which suggest particles to cells. They organize false peasants, thereby capturing food. Imaginary food residues are removed from the body through the oral hole.

Between all these cells there are small undifferentiated intermediate cells, which can turn into any other cell types, regeneration (the process of restoring lost or damaged parts of the body) is due to these cells.

Reproduction:

· Palm (vegetative). In the summer, under favorable conditions, there is a binding.

· Paul. In the fall, with the onset of unfavorable conditions. Sex glands are formed in the form of tubercles in Etoderma. In hermaphroditic forms, they are formed in different places. The sementers are developing closer to the mouth of the pole, and the ovaries closer to the sole. Fertilization cross. The fertilized egg (zygote) dresses with dense shells and falls to the bottom, where and winter. A young hydra comes out of the next spring.

Scifoid class

The class of scamphoid jellyfish is found in all seas. There are views of jellyfish, adapted to live in large rivers flowing into the sea. The body of the scaffolding has the appearance of a rounded umbrella or bell, on the bottom concave side of which the oral skeleton is placed. The mouth leads to the derivative of the dermis - the throat, which opens in the stomach. Radial channels forming a gastral system differ from the stomach.

Due to the free lifestyle of the jellyfish, the structure of their nervous system and senses is becoming more difficult: clusters of nerve cells appear in the form of nodules - ganglia, the equilibrium organs are stampets, photosensitive eyes.

The scaffolding has blinking cells located on the tentacles around the mouth. Their burns are very sensitive even for a person.

Reproduction:

Medusa separation, male and female sex cells are formed in the Entoderm. The fusion of genital cells in some shapes occurs in the stomach, in the other in the water. Medusa combine in the features of development and their own and hydroid signs.

Among the jellyfish there are giants - Fizaria or Portuguese boat (from 3rd and more in diameter, tentacles up to 30 m).

Value:

· Es eaten

· Some jellyfish are deadly and poisonous for a person. So, for example, with the bite of the root, significant burns may occur. When the crusal bite is disturbed by the activities of all human body systems. The first meeting with the crossed is not dangerous, the second is fraught with the consequences due to the development of anofiloxy. Bite tropical jellyfish leads to death.

Class coral polyps

All representatives of this class are the inhabitants of the seas and oceans. Mostly in warm waters. There are both single corals and colonial forms. Their bag-shaped body with the help of the sole is attached to underwater subjects (in single forms) or directly to the colony. The characteristic feature of corals is the presence of a skeleton, which can be either lime, or consist of a rog-like in-Va and is located either inside the body or outside (there is no skeleton from actinium).

All coral polyps are divided into two groups: eight-beam and six. The first is always eight proveman (sea feathers, red and white corals). At the sixth number, the tentacle is always a multiple of six (Actinia, Mad Paren corals, etc.).

Reproduction:

Coral polyps are separate animals, fertilization occurs in water. The zygota develops a larva - I planned. I planned attached to various underwater objects, turns into a polyp, which already has a mouth and a whisk of a supreet. The colonial forms in the future there is a congestion, and the kidneys are not separated from the parent organism. Polypov colonies are involved in the formation of reefs, atolls, coral islands.