The most important functions of the receipt of substances, their transformation and removal ...
The body of cuisons of mollusks bilateral-symmetric, divided into head and torso. The foot was transformed into a tentacle and a funnel. The sink in primitive forms is outdoor, multi-chamber (Nautilus Pompilius), at the highest representatives - internal reduced, is often absent. On the head is the mouth, surrounded by tentacles, and large eyes. At the tentacles most species are suckers.
fig. one. Octopus structure scheme:
1 - Goryra, 2 - Zhaba Heart, 3 - Kidneys, 4 - Heart,
5 - floor gland, 6 - intestines, 7 - stomach,
8.9 - ink bags, 10 - pancreas,
11 - Mantle Musculature, 12 - Liver, 13 - goiter,
14 - poisonous iron, 15 - skull, 16 - brain,
17 - Head Vienna, 18 - Pipper Muscles,
19 - Sadlotets nerves, 20 - beak, 21 - funnel.
Covers are represented by a single-layer epithelium and a layer of connective tissue. The skin has pigment cells - chromatophores, thanks to which cephalopods can quickly change body color.
The mantle cavity located on the abdominal side opens anal, sexual and excretory holes. To quickly move, the cephalopier use a jet method: with strong muscle contractions, water ejected through a mantle cavity funnel, the return pushes the body in the opposite direction.
Championship - predators. They feed on fish, crustaceans, molluscs dr. Production is grasped by tentacles and is killed by solid horny jaws and poison. In the throat is the language with the Radule. In the throat flows 1-2 pairs of salivary glands, which distinguish enzymes, splitting proteins and polysaccharides. The second rear pair of salivary glands highlights poison. The esophagus passes through the brain, so there should be large particles in the food cashia. Behind the esophagus follow the stomach, the small intestine, the rear, ending with the anal hole. The stomach flows the liver and "pancreas". In the back of the ink bag opens. Its secret is ejected in case of danger through anal hole. "Ink" form in water as it were, a smoke vest that allows a chance to escape from the pursuer.
Respiratory authorities are represented by real habia (claddia) located in the mantle cavity on the sides of the body.
In the circulatory system there is a heart consisting of ventricle and atrial (two or four), in addition there are two so-called "gill hearts", which, rhythmically shrinking, pushed blood through the gills. Oxidized blood returns to the heart. Blood contains a breathing pigment hemocianin, which includes copper. When oxidation, such blood "pigeon".
The excretory system consists of two or four kidneys. Their inner ends open into pericardium, and the outer holes in the mantle cavity.
The nervous system in charts is the most highly organized among all invertebrates. Ganglia form a general ocularity nervous mass protected by a cartilaginous skull. Well developed smell. The organs of the vision are presented in large, difficult to arranged eyes that are capable of accommodation. In contrast to the human eye, accommodation is carried out without a change in the curvature of the lens, but the approximation or removal of the lens relative to the retina.
fig. 2. Ammonite
(reconstruction)
fig. 3.
A - sink,
B - appearance
(reconstruction):
1 - Rostrum.
Channel clams - separation. Fertilization occurs in the mantle cavity of the female. Development direct. Some species take care of the offspring.
Class of ceponodium is divided into two subclasses: Nautiloidea, Coleoidae (Coleoidae).
There were challenges in the Cambrian period of the Paleozoic era. The first cephalopions had an outer straight sink, divided by cameras. The length of such shells reached 4-5 m. From the Devonian period of the Paleozoic era, ammonites are known (Fig. 2). Ammonites had a spiral swirling multi-chain sink, whose revisions were in the same plane. The diameter of ammonite shells reached 2 m. In the chalk period, the Mesozoic era ammonites die off. Ammonites were among the most common animals of the Mesozoic era, their fossil shells serve as guiding forms in geology to determine the age of reservoirs. Belemnites appeared in the TRIASE Mesozoic Era. On the shape of the body, they resembled modern squids (Fig. 3). But their inner shell was conical and multi-chamber. End Rostrums of their shells, which can be found in geological sediments, are called "damn fingers." The length of the body of some types of Belemnitis reached several meters. Belemnites were widespread in the Jurassic Mesozoic era and completely extinct to the middle of the Paleogen of the Cenozoic Era. In the chalk period of the Mesozoic era, flagelons appear, with a complex nervous system and senses, with reactive movement, with internal reduced sink. Colaoids reach the highest flourishing to date.
Description of classes, subclasses and lights of the type of mollusks:
Labor Class (Gastropoda)
Topic: "CHILDRATE MOLLEX".
Purpose: Examine the features of the structure and vital activity of challenges.
Tasks:
Educational: To form knowledge about the biological role of mollusks, their practical human significance, to study the features of the livelihoods of animals of this class.
Educational: Environmental education.
Developing: Develop memory, thinking, imagination.
A type: combined.
Methods: verbal, visual.
Funds: Pictures, equipment, slides.
The form: Frontal, group, individual.
Plan
Habitat foams.
The external and internal structure of the charts (on the example of octopus).
Practical significance.
Speech of students in groups: 1 group - squid, 2 group - Caracatar.
The dimensions of challenges are very different. Among them there are dwarfs, such as Caracatians of whose mantle length less than 1 cm, and there are also giants, to the number of which, first of all, belong to squid, the length of their bodies together with tentacles can reach 18 m.
The following follows the story of the teacher about the structure and features of the octopus. In parallel, students write down the supporting moments in the notebook.
Changs are mollusks - bilateral symmetric animals with an outer or inner sink. In Caracatiet, it has a type of plate lying under the mantle and as a shield covering the body of the mollusk from the back. Squid sink has the form of a thin transparent plate, in shape resembling a Roman sword. The octopuses from the shells remained, and even then not all, cartilage formations in the form of chopsticks or curved plates that support fins.
In Caracatians, the torso is flattered, in squid-cylindrical, pointed to the rear end, spindleless or conical; Octopresses - bag-shaped. All congorative torso is dressed in a skin-muscular bag - mantia, which concludes internal organs. On the sides of the mantle in squid, Caracatians, octopus are plans, which are the most diverse shape and size and serve molluscs for swimming and as steering.
So, the body consists of a torso and head.
Digestive system:The throat is muscular, with two strong jaws resembling a parrot beak and called "beak". In it flows the docks of poisonous salivary glands. In the oral cavity on a special language-shaped protrusion, Radules are placed - a meant, seated with rows of small teeth. With the help of the Radules of the food, which fell into the mouth of the mollusk and moistened with saliva, is transported further into the esophagus. The bottom octopuses use a very strong Radun for drilling the shells of bivalve and buncoullow mollusks and for scratching pieces of meat from under the shells of caught crabs. From the pharynx to the stomach stretches the thin tube - the esophagus piercing on the way to the stomach brain and the liver. Therefore, cephalopod, despite the big appetite, cannot swallow the mining entirely, and forced to crush it into small pieces of "beak" before sending it to the mouth. The eaten pieces of food, then fall into a muscular stomach, where digestive juices produced by the liver and pancreas come. The activity of the enzymes of these glands is very high, and for 4 hours is digested. Unpained food residues enter the intestine and thrown out. The liver performs several functions - produces digestive enzymes, the amino acid suction takes place in it, it is the storage of spare nutrients. On the abdominal side is a ink bag with a duct, which flows into the intestine. The ink bag is available in most chasing.
Respiratory system:Breathe with the help of the gills (one or two pairs located in the mantle cavity).
Circulatory system: The blood system is almost closed, there are additional gill hearts, reinforcing blood flow. Blood is driven by three hearts: the main, consisting of ventricle and two atrial, and two gill. The frequency of heartbeat in the octopus comes up to 50 shots per minute. The skin, muscles have capillaries. Blood poglong has a blue color due to the presence of a hemocyanine hemocyanin respiratory pigment in it containing copper.
Selective system:The excretion authorities serve renal bags, the appendages of gill hearts, the gills themselves.
Nervous system: The central nervous system in the form of a complex arranged brain, surrounded by a cartilage cranial capsule. Ganglia is very close to and form a large brain. 2 large nerves depart from it.
Feeling authorities: On the head, large complex eyes are complex. Their senses are highly developed. The eyes of challenges of mollusks for the complexity of the structure resemble the eyes of fish, and in visual sharpness are not inferior to the eyes of a person. Eyes are usually placed in the deepening of the cartilage head capsule and have a cornea, a frame with a capable of narrowing and expanding the pupil, lens and retina. There is even an eyelid, which can close the eye, except the organ of vision, there are organs of chemical feeling, equilibrium, tactile cells, photosensitive and flavoring.
Sex system, reproduction. Separation. Development direct.
Compilation of the reference scheme:
Features of charts:
horn jaws.
poisonous salivary glands.
ink bag.
brain
eyes
almost closed circulatory system.
separation.
Reflection: Implementation of an interactive task (frontal)
Which of the named mollusks belongs to the cephalopion class:
2. Octopus and squid moves with:
A. Feet. B. Legs and sucks. B. reactive movement. G. The flow of water.
3. The most highly developed among mollusks are:
A. Kalmar. B. Perllove. V. Middi. Snail.
4. Ink iron is available at:
A. All mollusks. B. Chaponogs. V.Rukhonogih. G. bivalve.
5. Which clams of the brain is enclosed in the capsule:
A. Oysters. B. Prudoviki. V. Octopus. Slizni.
Right answers: 1G, 2V, 3A, 4B, 5V.
Self-adjusting, setting accounted for work.
5. Homework: repeat the topic of mollusks, prepare for independent work.
CHONE CLASS (CEPHALOPODA)
Changated - the most highly organized mollusks. They are fairly called the "primates" of the sea among invertebrate animals for the perfection of their adaptations to life in the marine environment and the complexity of behavior. This is mostly large predatory marine animals that can actively swim in the thickness of water. These include squid, octopuses, Caracatians, Nautilosa (Fig. 234). Their body consists of a torso and head, and the leg is converted to the tentacles located on the head around the mouth, and a special motor funnel on the abdominal side of the body (Fig. 234, a). Hence the name happened - cephalopod. It has been proven that part of the fugitive fools is formed at the expense of head appendages.
Most modern charts are missing or rudimentary. Only in the genus nautilus (Nautilus) there is a spiral swirling sink, divided into chambers (Fig. 235).
There are only 650 species to modern charts, and fossil species are about 11 thousand. This is an ancient group of mollusks known to Cambrian. Furious types of cephalopions were predominantly sinks and had an outer or inner sink (Fig. 236).
For chaptions, many progressive features of the organization are characterized due to the active lifestyle of marine predators. At the same time, they preserve some primitive signs indicating their ancient origin.
External structure. Features of the external structure of chasters are diverse due to different ways of life. Their sizes range from several centimeters to 18 m in some squid. Non-definition cephalopods are usually a torpedo-shaped (most squid), benthosses have a bag shape (many octopus), nectobenty - complicated (Caracatar). Planktonal species are small in size, have a pupilly floating body. The shape of the body in plankton champion can be a narrow or similar to jellyfish, and sometimes spherical (squid, octopus). Bent-benthelagic cephalopods have a sink divided by cameras.
The body of the charts consists of head and torso. The foot is modified in tentacles and funnel. On the head is the mouth, surrounded by tentacles, and large eyes. The tentacles are formed by head appendages and foot. These are organ capture organs. At the primitive pinched - the ship (Nautilus), the tentacled by an indefinite amount (about 90); They are smooth, worm-shaped. At the highest charts, the tentacles are long, with powerful muscles and carry large suckers on the inner surface. The number of the tentale is 8-10. Two tentacles have 10 tentacles - culls, longer, with suckers on extended ends,
Fig. 234. CHONEGOGE MOLUME: A - Nautilus Nautilus, b - benthoctopus octopus; 1 - Tentacles, 2 - Flows, 3 - Hood, 4 - Eye
Fig. 235. Nautilus Nautilus Pompilius with a sawn sink (on OUNENA): 1 - Head Hood, 2 - Tentacles, 3 - Funnel, 4 - Eye, 5 - Mantle, 6 - Internal Bag, 7 - Cameras, 8 - Partition Between Shell Cameras, 9 - siphon
Fig. 236. The scheme of the structure of the shells of cipal caps in the Saggital section (from Hescher): A - SEPIA, B - Belosepia, B - Belemnites, G - Spirulirostra, D - Spirula, E - Ostracoteuthis, Well - Ommastrephes, Z - LOLIGOPSIS (B, G, E - fossils); 1 - Prostrakum, 2 - the spinal edge of the siphon tube, 3 - the abdominal edge of the siphon pipe, 4 - a set of chamber fragmocon, 5 - Rostrum, 6 - the cavity of the siphon
Fig. 237. Mantle cavity Caracatizen - Sepia (Pfursheller): 1 - short tentacles, 2 - Capture tentacles, 3 - mouth, 4 - Hole funnels, 5 - Funnel, 6 - cartilage foxes Cufflinks, 7 - Anus, 8 - renal papillas, 9 - gender papilla, 10 - Zhabra, 11 - fin, 72 - Line of cutting mantle, 13 - mantle, 14 - cartilage tubercles Cufflinks, 15 - Mantle gangli
and the remaining eight proveman is shorter (squid, Caracatia). At octopuses that live on the seabed, eight proven of the same length. They serve as octopus not only for the capture of food, but also for moving along the bottom. In males octopus, one tentacle is modified into sexual (hectotil) and serves to transfer sex products into the mantle cavity of the female.
Funnel - a derivative of the legs in charts, serves for the "reactive" method of movement. Through the funnel, water with force is pushed out of the mantle cavity of the mollusk, and its body moves reactive in the opposite direction. At the shoe, the funnel did not grieve on the abdominal side and reminds the legs of crawling clams into the tube. Proof of the fact that the tentacles and funnel of charts are derived legs, serves their innervation from pedal ganglia and embryonic laying of these organs on the abdominal side of the embryo. But, as already noted, part of the fugitive fools - derivatives of head appendages.
The mantle on the abdominal side forms as it were for a pocket - a mantle cavity, which opens out the transverse slit (Fig. 237). From this crack is a funnel. On the inner surface of the mantle there are cartilage protrusions - cufflinks that are tightly included in the cartilaginous deepening on the body of the mollusk, and the mantle is fastened to the body.
The mantle cavity and funnel in the aggregate provide reactive movement. When relaxing the musculature of the mantle, water enters the slot into the mantle cavity, and when it is reduced, the cavity closes on the cufflinks and the water is pushed out through the funnel outside. The funnel is able to bend to the right, left and even back, which provides a different direction of movement. The role of the steering wheel is additionally performed by tentacles and fins - skin folds of the body. Types of movement in charts are diverse. Octopuses are more often moving on the tentacles and less often swim. In addition to the funnel, Caracatians serves a circular fin. Some deep-water octopuses of an umbrella-shaped form have a membrane between tentacles - Umbrell and can move at the expense of its abbreviations, like meduzam.
Sink in modern champion rudimentary or absent. The ancient extinct champions of the sink was well developed. Only one modern genus Nautilus retained the developed shell. Nautilus sink and fossil forms have significant morphofunctional features, in contrast to the shells of other clams. This is not only a protective device, but also a hydrostatic apparatus. Nautilus has spirally twisted shell separated by partitions on the camera. The body of the mollusk is placed only in the last chamber, which opens outwards. The remaining chambers are filled with gas and chamber fluid, which ensures the buoyancy of the body of the mollusk. Through
holes in partitions between the sink cameras passes the siphon - the rear body of the body. Siphon cells are capable of separating gases. When pop-up, the mollusk highlights gases, displacing chamber fluid from the chambers; When lowering on the bottom, the mollusk fills the chambers of the chain by chamber fluid. The propulsion from Nautilus is a funnel, and the sink supports his body suspended in water. Fossils of Naililids had a similar shell, like a modern Nautilus. In fully extinct champion - ammonites also had an outer, spirally swirling sink with cameras, but they had a wavy structure between the cameras, which increased the strength of the sink. That is why ammonites could reach very large sizes, up to 2 m in diameter. In another group of extinct champions - Belemnitis (Belemnoidea), the sink was internal, increasing skin. Bellemnitis on appearance resembled cerebral squids, but there was a conical sink in their body, divided by cameras. The top of the shell ended with the edge - Rostrum. Rostrums of the shells of Belemnitis are often found in chalk sediments, and they are called "damn fingers". In some modern, unpleasant charts, there are rudiments of the inner shell. Thus, the Caracatians on the back under the skin remains a lime plate having a chamber structure (238, b) on a slice. Only in Spirly (Spirula) under the skin there is a completely developed spiral screwed sink (Fig. 238, a), and only a horny plate remained under the skin under the skin. In the females of modern champion - Argonauts (Argonauta), a brood chamber is developed, resembling a spiral shell. But this is only an external similarity. The brood camera is highlighted by the epithelium of the tental, very thin and intended to protect developing eggs.
Pokrov. The skin is represented by a single-layer epithelium and a layer of connective tissue. The skin has pigment cells - chromatophores. The coding is characterized by the ability to quickly change the color. This mechanism is controlled by the nervous system and is carried out by changing the form.
Fig. 238. Rudiments of the sinks in chasing (on Natalie and Dogel): A - Spirula (Spirlau); 1 - funnel, 2 - mantle cavity, 3 - anus, 4 - excretory hole, 5 - glow body, 6 - fin, 7 - sink, 8 - siphon; B - sink sepia; 1 - partitions, 2 - side edge, 3 - siphonal jam, 4 - Rostrum, 5 - Rudiment of the siphon, 6 - rear edge of the forecast
pigment cells. So, for example, Caracatia, swimming over the sandy soil, takes a bright color, and over the stony soil is dark. . For this in its skin, pigment cells with a dark and light pigment alternately are compressed, then expand. If you cut the visual nerves from the mollusk, then it loses the ability to change the color. Due to the connective tissue of the skin, cartilage are formed: in cufflinks, the bases of the supreets, around the brain.
Protective devices. Channel, losing in the process of evolution of the sink, acquired other protective devices. First, the predators of many of them saves fast movement. In addition, they can be protected by tentacles and "beak", which is modified jaws. Large squids and octopuses can join large marine animals, such as coushlots. In selection and small forms, the patrons are developed and the ability to quickly change the color. Finally, some cephalopods, for example, in Caracatin, there is a ink bag, which is opened in the rear. Putting the ink fluid into the water causes a smoke veil that allows mollusk to hide from predators to a safe place. Caracatiet inky gland pigment is used to make a high-quality art carcass.
Internal structure of champion
Digestive system The charts bearing the features of the feeding of animal food (Fig. 239). His food serve mainly fish, crabs and bivalve mollusks. Prey they grab tentacles and kill with jaws and poison. Despite major sizes, cephalopods can only be powered by liquid food, as they have a very narrow esophagus, which passes through the brain enclosed in the cartilage capsule. Channels have tools for food inheritance. For discharges of prey, they serve solid horny jaws, similar to the beak of the parrot. In the sip of food, he is swelled and richly wetted with saliva. In the throat flows 1-2 pairs of salivary glands, which distinguish enzymes, splitting proteins and polysaccharides. The second rear pair of salivary glands highlights poison. The liquid food from the pharynx in a narrow esophagus enters the entodermal stomach, where the ducts of the steam liver, producing a variety of digestive enzymes. Hepatic ducts are seated with small additional glands, the totality of which is called the pancreas. Enzymes of this gland act on polysaccharides,
and, therefore, this iron is functionally different from the pancreas of mammals. The stomach charts is usually with a blind bag-shaped process that increases its volume, which allows them to absorb a large portion of food. Like other predatory animals, they eat a lot and relatively rarely. A thin middle intestine is departed from the stomach, which then goes into the rear, opening anal hole in the mantle cavity. In the back intestine, many cephalopods flows ink bond, the secret of which has a protective value.
Nervous system Charts are the most highly developed among mollusks. Nervous ganglia form a large ocular cluster - brain (Fig. 240), enclosed in a cartilage capsule. There are additional ganglia. The composition of the brain primarily includes: a pair of large cerebral ganglia, innervating heads, and a couple of visceral ganglia, sending nervous chips to the internal organs. On the sides of the cerebral ganglia, additional major optical ganglia are located, innervating eyes. Long nerves are departed from visceral gangglias to two ganglines of the star form, developing in charts due to the function of the mantle in their reactive movement method. In addition to cerebral and visceral pedal ganglia, which are divided into pair ganglia tental (brachial) and funnels (infidibular), in the composition of the brain. The primitive nervous system, similar to the staircase system of sneakers and monoplacora, is preserved only from Nautilus. It is represented by nervous hill, forming a windowless ring without ganglia and a pedal arc. Nervous trenches are covered with nerve cells. Such a structure of the nervous system indicates an ancient origin of charts from primitive shellfish.
Sense organs Charts are well developed. Especially complex development they achieve eyes having the greatest value for orientation in space and prey hunting. Nautilus eyes have a simple structure in the form of a deep eye hole (Fig. 241, a), and the remaining charts are complex eyes - in the form of the eye bubble and resemble the structure of the eyes in mammals. This is an interesting example of convergence between invertebrates and vertebral animals. Figure 241, B depicts the eye Caracatar. From above, the eyeball is covered with a cornea, in which there is a hole in the front chamber of the eye. The connection of the front cavity of the eye with the external environment protects the eyes of chappings from high pressure at large depths. Rainbow shell forms a hole - pupil. Light through the pupil falls on a ball crystal, formed by the epithelial body - the upper sheath of the eye bubble. Accommodation Eyes in charts occurs differently,
Fig. 239. Digestive system of Caracatar sepia officinalis (on reserved and lamps): 1 - Harness, 2 - common salivary duct, 3 - salivary ducts, 4 - rear salivary iron, 5 - esophagus, 6 - Head Aorta, 7 - liver, 8 - Pancreas, 9 - stomach, 10 - blind bag stomach, 11 - small intestine, 12 - liver duct, 13 - direct intestine, 14 - ink bag duct, 15 - anus, 16 - head cartilage capsule (cut), 17 - stavocist , 18 - Nervous Ring (cut)
Fig. 240. Nervous System Champion: 1 - Brain, 2 - Optical Ganglia, 3 - Mantle Ganglia, 4 - Intestinal Ganglia, 5 - Nervous Train in Tentacles
Fig. 241. Eyes of champion: A - Nautilus, b - sepia (according to the General); 1 - cavity of the eye jams, 2 - retina, 3 - visual nerves, 4 - cornea, 5 - lens, 6 - front camera eye, 7 - Rainzing, 8 - eyelash muscles, 9 - vitreous body, 10 - eye-eye processes cartilage capsules, 11 - Optical Ganglia, 12 - Scler, 13 - Holes Camera Eyes, 14 - Epithelial Body
than in mammals: not by changing the curvature of the lens, but by approaching it or removal from the retina (like focusing the camera). Special crustacean muscles are suitable for lens, leading it in motion. The cavity of the eyeball is filled with a vitreous body having a light-strain fuch. The bottom of the eyes is waved with visual - retinal and pigment - cells. This is a retina eye. From it there is a short visual nerve to optical ganglia. Eyes together with optical ganglions are surrounded by a cartilage capsule. In deep-water charts on the body there are glow bodies built by eye type.
Equilibrium authorities - Stavtocists are located in the cartilage brain capsule. The smell bodies are represented by olfactory pits under the eyes or typical asfrades for mollusks at the base of the Glabers - Nautilus. Taste organs are concentrated on the inside of the end of the supreets. Octopuses, for example, with the help of a tental distinguish edible objects from inedible. On the skin of coding many tactile and light-sensitive cells. In search of mining, they are guided by a combination of visual, tactile and taste sensations.
Respiratory system represented by cladids. The majority of modern charts have two, and Nautilus is four. They are located in the mantle cavity on the sides of the body. The water current in the mantle cavity, providing gas exchange, is determined by the rhythmic reduction in the muscles of the mantle and the funnel function through which the water is ejected out. During the reactive method of movement of the water current in the mantle cavity, the respiratory intensity increases.
Circulatory system Chappings are almost closed (Fig. 242). Due to the active movement, they are well developed whole and blood vessels and, accordingly, the parenchymality is poorly expressed. Unlike the other mollusks, they do not suffer in hypochenia - weak mobility. The speed of blood flow is ensured by the work of a well-developed heart consisting of ventricle and two (or four - nautilus) atrial, as well as pulsating vessels. The heart is surrounded by an extensive pericardial cavity,
Fig. 242. Blood Systems of challenges (from Abrikosov): 1 - Heart, 2 - Aorta, 3, 4 - Vienna, 5 - Label vessels, 6 - gill hearts, 7, 8 - Power kidney system, 9 - gill veins
which performs many functions of the organizer. The head aorta is departed from the ventricle of the heart - ahead and an internal aorta - back. The head aorta branches on the arteries supplying the head and tentacle blood. Vessels to internal organs depart from the internal aorta. Blood from the head and internal organs is collected in a hollow vein located longitudinally at the bottom of the body. Hollow vein is divided into two (or four Nautilus) bringing the gill vessels, which form short-range extensions - gill "hearts", contributing to gill blood circulation. Given vessels adjacent to the kidney adjacent to the kidney, forming small blind piercing into the kidney tissue, which contributes to the release of venous blood from the exchange products. In the gill capillaries, blood oxidation occurs, which then enters the gill vessels, flowing into atrium. Partially blood from the capillaries of the veins and the arteries flows into small lacuna, and therefore the circulatory system should be considered almost closed. Blood poglong contains a respiratory pigment - the hemocyanin, which includes copper, so when oxidizing blood pigeons.
Selective system Presented two or four (Nautilus) kidneys. They are opened in the internal ends in the oolocrine bag (pericardium), and external - to the mantle cavity. Selection products come in kidneys from gill veins and from an extensive pericardial cavity. Additionally, the excretory function is performed by pericardial glands formed by the wall, pericardium.
Sex system, reproduction and development. Chulp - separation animals. In some species, sexual dimorphism is well expressed, for example, Argonauta (Argonauta). The female of the Argonaut is larger than the male (Fig. 243) and during the period of reproduction it allocates around the body with the help of special glands on the tentacles, the thin-walled parchment-like pulling chamber to carry eggs similar to a spiral sink. Argonaut male several times less females and has a special elongated sexual tentacle, filled during the period of reproduction by sexual products.
Gonads and sex ducts are not partial. The exclusion is nautilus, which has steady ducts that depart from the unpaired gonad. In males, the seed tube goes into a sperm bag, where spermatozoa glued into special packages - spermatophores. At Caracatin, the spermatophore has a shape of checkers; Its cavity is filled with spermatozoa, and the outlet is closed with a complex cork. During the reproduction period, Karakatitsa, with the help of a floor tentacle, a sperm transfers to the mantle cavity of the female.
Fig. 243. Mollusk Argonauta (Argonauta): A - female, b - male; 1 - Fleet, 2 - Eye, 3 - Sink, 4 - hectoon, 5 - Funnel, 6 - Eye (on the doogle)
Changs are set up eggs usually at the bottom. Some species have concern for offspring. Thus, the female of the Argonaut carries eggs in the brood chamber, and the octopuses guard the masonry of the eggs, which is placed in shelters from stones or in caves. Development direct, without metamorphosis. From eggs are small, quite formed codifications of mollusks.
Modern cephalopions belong to two subclasses: a subclass of Nautilides (Nautiloidea) and the Coleoidea subclass (Coleoidea). Extinct subclasses include: Amplisted Ammonites (Ammonoidea), a subclass of Bactrites (Bactritoidea) and the Belmnoidea subclass (BELEMNOIDEA).
Subclass of Nautiloidea
Modern scientists include one NautiLida detachment. It is represented only by one nautilus, to which only a few species belongs. The distribution area of \u200b\u200bNautilus is limited to the tropical regions of the Indian and Pacific Oceans. Fossils Natailid has more than 2500 species. This is an ancient group of charts, known with Cambrian.
Naililids possess many primitive features: the presence of outer multi-chamber shell, unreasonable funnel, numerous tentacles without suckers, manifestation of metamery (four ktoenidia, four kidneys, four atrium). The similarity of NailTid with lower shellfish is manifested in the structure of the nervous system of heavyness without separable ganglia, as well as in the structure of the colodel.
Nautilus refers to a benthoplagic chart. It floats in the thickness of the water "reactive" in the way, pushing the water from the funnel. The multi-chamber sink ensures the buoyancy of its body and lowering on the bottom. Nautilus has long been the object of fishery due to the beautiful pearl sink. Nautilus's shells made a lot of sophisticated jewelry.
Caloidal subclass (Coleoidea)
Coleoidea translated from Latin means "hard". These are tininess of mollusks, devoid of shells. Colaoids - a prosperous group of modern charts, includes four detachments to which about 650 species applies.
The common features of the subclass are: the absence of a developed shell, a surprised funnel, a tentacle with suction cups.
Unlike Naililid, they have only two khtenidius, two kidneys and two atrium. Coleoidea has a high development of the nervous system and senses. The largest number of species are characterized by the following three detachments.
Sepiida detachment. The most characteristic representatives of the detachment are Caracatians (SEPIA) and Spirula (Spirula) with rudiments of the inner shell. They have 10 tentacles, two of whom ads. These are nectobent animals, keep at the bottom and are able to actively swim.
Tuthida squid. This includes many fishing squids: Todarodes, Loligo, and others. Squids sometimes persist rudiment
shells in the form of a lean plate under the skin on the back. They have 10 sucks, as in the previous squad. These are mostly neconic animals that are actively floating in the thickness of water having a torpedo-shaped body shape (Fig. 244).
Octopoda detachment. This is an evolutionary advanced group of charts without traces of the sink. They have eight sucks. Policy dimorphism is expressed. The males develops a sexual tentacle - hectober. This includes a variety of octopus (Fig. 245). Most octopuses lead the bottom lifestyle. But among them there are nectant and even planktonial forms. The OCTOPODA detachment refers to Argonauta - Argonaut, who has a special brood chamber in whom the female allocates a female.
Fig. 244. Squid Loligo (from Dogel)
Fig. 245. Octopus (male) Ocythoe (on Pelsnera): 1 - Tentacles, 2 - Funnel, 3 - hectober, 4 - Pouch, 5 - End thread
Practical value of cephalopod
Changs of mollusks - fishing animals. Meat Caracatiet, squid and octopus engines are used in food. The world catch of charts currently reaches more than 1600 thousand tons. in year. Caracatians and some octopuses are also mined in order to obtain the ink fluid, from which the natural mascara and the ink of the highest quality is manufactured.
Paleontology and philogenation of charts
The most ancient group of charts consider NailTide, whose fossil shells are already known in Cambrian deposits. Primitive scientists had a low conical sink just with several cameras and with a wide siphon. It is assumed that cephalopods occurred from the ancient crawling shellfish with a simple conical sink and a flat sole, as in some fossil monoplacor. Apparently, substantial aromorphosis in the occurrence of poles was in the appearance of the first partitions and cameras in the sink, which marked the beginning of the development of the hydrostatic apparatus and determined the opportunity to pop up, breaking away from the bottom. Apparently, at parallel, the formation of a funnel and a tental. The shells of the ancient Naililid were diverse in shape: long conical and flat spirally twisted with different numbers of cameras. Among them were giants to 4-5 m (EndoceraS), which led the bottom lifestyle. Nailites have undergone in the process of historical development several periods of heyday and extinction and existed to this day, although it is now available to just one nautilus.
In Devonia, in parallel with Naililids, a special group of charts - Bactrites (Bactritoidea) begins to meet, smaller in size and less specialized than Naillis. It is assumed that this group of charts occurred from the general while unknown ancestors with Nailudi. Bactrites turned out to be an evolutionary promising group. They gave rise to two branches of cephalophals: ammonites and whitening.
The subclass of ammonites (ammonoidea) appeared in Devon and died at the end of the chalk. During the heyday, the ammonites were successfully competed with Naililids, the number of which at this time fell markedly. It is difficult for us to judge the benefits of the internal organization of ammonites only for fossil sinks. But ammonite sink was more perfect,
Fig. 246. Fossil cephalopod: A - ammonite, b - Belemnit
than Nailid: easier and more durable. Partitions between the cameras in ammonites were not smooth, but wavy, and the lines of partitions on the sink zigzag, which increased the strength of the sink. Ammonite sinks were spirally twisted. More often, the spirals of the spirals of ammonites were located in the same plane, and less often had the shape of Turbochiral (Fig. 246, a). According to some body imprints of fossil residues of ammonites, it can be assumed that they had up to 10 tentacles, possibly there were two katyidide, coasty jaws, an ink bag. This suggests that ammonites, apparently, there has been an oligomerization of metairic organs. According to Paleontology, ammonites were environmentally more diverse than Nailways, and among them there were nectonic, benthosses and plankton forms. Most ammonites had small sizes, but giants with the diameter of the shell up to 2 m. Ammonites were among the most numerous marine animals in the mesozoic, and their fossil shells serve as guidelines in geology to determine the age of reservoirs.
Another branch of the evolution of chapports, hypothetically derived from the Bactrites was represented by the Belmnoidea subclass. Belemnites appeared in Triassa, flourished in the chalk period and died out at the beginning of the Cenozoic era. By their appearance, they are closer to the modern subclass of Coleoidea. On the shape of the body, they resemble modern squids (Fig. 246, b). However, Belemnites significantly differed from them by the presence of a heavy shell, which turned the mantle. Bellemnitis sink was a conical, multi-chamber, leather-covered. In geological sediments, the remnants of shells have been preserved and especially their end finger-like Rostrums, which are figuratively called "damn fingers". Belemnites were often very large: their length reached several meters. The extinction of ammonites and whites was probably due to increased competition with bony fish. And here in Cenozoa, a new group of cephalovogo-flames (Coleoidea subclass), devoid of shells, with a rapid reactive movement, with a complex nervous system and the senses and senses. They became the "primates" of the sea and could compete on equalities as predators with fish. This group of charts appeared yet
in chalk, but the highest heyday reached the Cenozoic Era. There is reason to believe that Coleoidea has common roots of origin with whiteness.
Environmental radiation of champion. The ecological radiation of the charts is presented in Figure 247. From primitive shell benthic forms that can emerge due to the hydrostatic apparatus, several ways of ecological specialization have been determined. The most ancient environmental directions were associated with radiation of Naililid and ammonites, which flooded at different depths and formed specialized shell forms of benthopelgic charts. Benthelagic forms are traced to the transition to bentonecton (type of whiteness). They make the sink inner, and its function of the swimming unit is weakening. In return, they develop the main drivers - a funnel. Later, they gave the beginning of the unclean forms. The latter undergo rapid ecological radiation by forming nectocentosny, nectant, bentos and planktonic forms.
The main representatives of necton are squid, but there are also fast-moving octopuses with a narrow torpedo-shaped body, Caracatians. The composition of nectobenthos is mainly among Caracatians, often floating
Fig. 247. Ecological radiation of charts
or lying on the bottom, to Bentonecton - octopuses that are more crawling along the bottom than swimming. The plankton includes umbrella-shaped, or jellies, octopuses, row-shaped squids.
Latin name Cephalopoda.
Challenges Molluscs General Characteristics
The most highly organized animals among invertebrates. This is a relatively small group (about 730 species) of marine predators, the evolution of which is associated with the reduction of the shell. Only the most primitive four-bed mollusks have an outer shell. The remaining biqueboat cephalopods, capable of fast and long-term movements, have only rudiments of sinks that play the role of internal skeletal formations.
Chanitogo is usually large animals, the length of their body is at least 1 cm. Among the deep-sea forms there are giants up to 18 m. Pelagic cephalopions (squid) have a streamlined body shape (similar to the missile), they move most quickly. At the rear end of their body there are fins - movement stabilizers. Bentos forms - octopuses - have a bagpath body, the front end of which forms a kind of parachute due to the affected bases.
External structure
The body of challenges of mollusks consists of head and torso. The foot characteristic of all mollusks is very modified. The back of the leg turned into a crooked tube, leading to the mantle cavity. The funnel is located behind the head on the abdominal side of the body. It is an organ with which the mollusks float. At the pine mollusk from the genus Nautilus, which has retained many the most ancient features of the cephalopod, the funnel is formed by coagulation in a leaf-foot tube having a conventional wide sole. At the same time, the wrapped edges of the legs do not grow. Nautilusi with the help of the leg either slowly crawl along the bottom, either rising and slowly floating carrying by trends. For other challenges of mollusks, the funnel blades are primarily separate, and in adult animals they grow into a solid tube.
Around the mouth, the crown is the tentacles, or hands that are seated with several rows of strong suckers and have a powerful muscles. It turns out that the tentacles of charts, like a funnel, are homologues of a part of the legs. In the germs of development, the tentacles are laid in the abdominal side behind the mouth from the feet of the foot, but then move forward and surround the oral hole. The tentacles and the funnel are innervated from the pedal ganglia. Most of the chartures 8 (in the octopods) or 10 (in ten), in primitive clams from the genus Nautilus - up to 90. The tentacles serve to capture food and movement; The last one is mostly gentle by the dark octopographers that go along the bottom on their nudchaupalts. Suckers on the Shchulpaltsy in many species are armed with chitinov hooks. At the leaders (Karakatitsa, squid), two out of ten supreets are much longer than others and seated on the extended ends of the suckers. This is the casual tentacles.
Mantle and mantle cavity
Mantle covers all the torso charts; On the dorsal stop, it grows with the body, on the abdominal side covers an extensive mantle cavity. The mantle cavity communicates with the external environment with a wide transverse gap, which is between mantle and body and the leading edge of the mantle behind a funnel. The wall of the mantle is very muscular.
The structure of a muscular mantle and a funnel is a device, with which the cephalopions float, and move the rear end of the body forward. This is a kind of "rocket" engine. In two places on the inner wall of the mantle at the base of the funnel there are cartilage protrusions, called cufflinks. When the muscles of the mantle decreases and presses to the body, the front edge of the mantle with the help of the cuffs, as it were, "fastened" to the recesses at the base of the funnel and the gap, leading to the mantle cavity, closes. At the same time, water with force is pushed out of the mantle cavity through a funnel. The body of the animal is discarded at a certain distance back. Then follows the relaxation of the muscles of the mantle, the cufflinks are "disassembled" and the water is absorbed through the mantle slot into the mantle cavity. Again the mantle and the body gets a new push. Thus, the quickly following each other alternately compression and stretching the muscles of the mantle make it possible to float at high speed (squid). The same mechanism creates water circulation in a mantle cavity, providing breathing (gas exchange).
In the mantle cavity there are gills with the structure of typical Ktoenidiev. In most chasing, one pair of Ktoenidiev, and only at the nautilus there are 2 pairs. This is found to divide the class of challenges of mollusks into two subclasses: bikes (dibranchia) and four-chamber (Tetrabranchia). In addition, anal hole is opening into the mantle cavity, a pair of excretory holes, floor holes and holes of the nidenmental glands; Nautilus in the mantle cavity is also placed by Offradia.
Sink
Most of the modern chasing the shells do not have completely (octopus) or it is rudimentary. Well developed thin shell is available at Nautilus. It should be borne in mind that the genus of nautiloslets is very ancient, very little changed since the time of Paleozoic. Nautilus shell is spinning spiral (in the symmetry plane) on the head. Inside, it is divided by partitions on the camera, and the body of the animal is placed only in front of the front, the largest chamber. From the back of the body of Nautilus, the process of siphon, which passes through all the partitions to the top of the shell. With this siphon, the chamber of the shell is filled with gas, which reduces the density of the animal.
For modern biker chipped, the inner underdeveloped shell is characteristic. The most fully spiral shell has been preserved only in a small mollusk Spirly leading a bottom lifestyle. The cuttlefish from the sink remains a wide and thick porous lime plate lying on the dorsal side under the mantle. It carries a reference function. Squid sink is represented by a narrow spinal chitinoid plate. Part of the octopuses has two koloilla sticks under the mantle. Many cephalopods completely lost her sink. Rudiments of the shell play the role of skeletal formations.
The inner cartilage skeleton, carrying the protective and reference function, appears in the chartoprogs. The biker is developed a cartilaginous head capsule surrounding the central nervous system and stavocists, as well as cartilage the bases of the supreets, fins and cufflinks of the mantle. The four-clicks have the only cartilage that supports the nervous centers and the front end of the digestive system.
Digestive system
The mouth is located at the front end of the body and is always surrounded by a ring of sucks. Roth leads to a muscular throat. It is armed with powerful horny jaws similar to the beak parrot. In the back of the pharynx is Radula. The throat of one or two pairs of salivary glands opens in the throat, the secret of which contains digestive enzymes.
The throat goes into a narrow long esophagus, opening into a bag-shaped stomach. In some species (for example, octopus), the esophagus forms a side protrusion - goiter. The stomach has a large blind appendage, which opens the duks usually two-blade liver. From the stomach, a thin (entodermic) intestine, which makes a loop, heading forward, and goes into the rectum. Direct, or rear, the intestine opens with an anal hole, or poroshires, in the mantle cavity.
Inhibit the ink bag dumps in the straight intestine. This pear-like iron highlights the ink fluid, which is thrown through the anal hole and creates a dark cloud in water. Ink iron serves as a protective device that helps its owner hide from persecution.
Respiratory system
Zhabra, or Ctenii, Channels are located symmetrically in the mantle cavity among one or two pairs. They have a peristry structure. The gills epithelium is devoid of cilia, and water circulation is ensured by rhythmic cuts of the muscles of the mantle.
Circulatory system
The heart of the charts is usually from the ventricle and two atrials, only the nautilus is four. Two aorts are departed from the ventricle - the head and abdominal, branching into a series of arteries. It is characterized by a large development of arterial and venous vessels and capillaries, which in the skin and muscles go into each other. The circulatory system becomes almost closed, lacques and sines are less extensive than in other mollusks. Blood from the organs is assembled according to venous sinus vessels in hollow veins, which form blind bumps, walking in the walls of the kidneys. Before entering claddia, bringing the gill vessels (hollow veins) form muscular expansions, or venous hearts, which pulsed and contribute to blood flow into the gills. Blood enrichment with oxygen occurs in gills capillaries, from where the bloodflow is coming to the atrium.
The blood is pigeon-baked blue, as its breathing pigment - hemocyanine - contains copper.
Secondary body cavity and excretory system
In cipaths, like in other mollusks, there is a reduction of the secondary cavity of the body, or the organizer. The most extensive whole, accommodating the heart, stomach, part of the intestines and gonads, is available at primitive four-bedable charts. In the ten-felt biker's whole, reduced more and is represented by two broken areas - pericardial and sex; The octopic biker pericardial whole is reduced even more and accommodates only pericardial glands, and the heart lies outside the agencies.
Outline organs are represented by two or four kidneys. They usually begin with funnels in the pericardial cavity (in some forms of kidneys lose touch with pericardium) and open with excretory holes in the mantle cavity, on the sides of the poroshires. The kidneys are closely associated with blind protrusions of venous vessels through which filtering and removing metabolic products from the blood occurs. Pericardial glands also carry excretory function.
Nervous system
Biker championship exceed the height of the organization of the nervous system of all invertebrate animals. All ganglia, peculiar to these mollusks, come closer and form a brain - the common nervous mass surrounding the beginning of the esophagus. Separate ganglia can be distinguished only at cuts. There is a division of paired pedal ganglia on Ganglia Provecan and Ganglia funnels. Nerves innervating the mantle and forming two large star gangliy in its upper part of the brain are departed from the back of the brain. Sympathetic nerves, innervating the digestive system, waste from buccal ganglia.
Primitive four-chamber nervous system is easier. It is represented by three nerve semirings, or arcs, - the durable and two sublighted. Nervous cells are distributed evenly, without forming ganglionic clusters. The structure of the nervous system of the four-chamber is very similar to such chitons.
Sense organs
In the charts they are highly developed. Tangible cells are located all over the body, especially they are concentrated on tentacles.
The fiction sentence authorities serve special olfactory pits, and the Offradia is only at Nautilus, i.e., four-bedrooms.
All charts have difficult arranged stavocists located in a cartilage capsule surrounding the brain.
The most important role in the life of cephalters, especially in the hunt for prey, eyes play, very large and greater complexity. The most simply arranged the eyes of Nautilus. They constitute a deep eye hole, the bottom of which forms the retina.
The eyes of biker champion are much more complicated. The eyes of Caracatians have a cornea, rainbow, a lens, a vitreous body and a very strongly developed retina. Draw attention to the following features of the eye of the charts. 1. In the cornea, many mollusks have a small hole. 2. Rainbill also forms a hole - pupil leading to the front eye chamber. Pupil can shrink and expand. 3. The spherical lens formed by two controversy halves is not capable of changing curvatures. Accommodation is achieved with the help of special eye muscles, which are removed or approaching a crystal to the retina, as is done when the photographic camera lens is installed on the focus. 4. The retina consists of a huge number of visual elements (1 mm 2 retina falls at Caracatar 105,000, and at Squid 162,000 visual cells).
The relative and absolute size of the eyes in cipaths is greater than that of other animals. So, the eyes of Caracatar only 10 times less than the length of her body. The diameter of the eye of a giant spruit reaches 40 cm, and the deep-water squid is about 30 cm.
Sex system and reproduction
All cephalopods separators, and in some very sharply expressed sexual dimorphism. An extreme example in this regard can serve as a wonderful mollusk from the ect of the boat (Argonauta Argo).
The shoe female is relatively large (up to 20 cm) and has a saccine of special origin, not homologous shell of other clams. This sink is not highlighted by mantle, but foot blades. Sink is thin, almost transparent and spirally twisted. It serves a brood camera in which eggs are cut. Male boat many times less females and has no shell.
Sex glands and sex ducts in most chasal unpaired. For females, the presence of two or three pair and one unpaired nidazenal glands, separating the substance from which the eggs is formed. Sammatov spermatozoa enclosed in sperm of various shapes.
Of great interest is the method of fertilization in chalk classes. The real mating does not happen. In the hawk males, one of the supreets is strongly changed, it turns into a hectochothylized tentacle, or hectotil. With this tentacle, the male pulls out spermatophores from its mantle cavity and transfers them into the mantle cavity of the female. In some chasing, especially the ship described above (Argonauta), hectochothylized tentacle has a complex structure. After filling the tentacle with spermatops, it leaves and floats independently, and then closer to the mantle cavity of the female, where fertilization occurs. Instead of the heated hectoon regenerates a new one.
Large eggs are postponed by groups on various underwater objects (under stones, etc.). Eggs are dressed with a dense shell and very rich in the yolk. The crushing is incomplete, discoomal. Development direct, without metamorphosis. From the egg comes out a small mollusk similar to an adult.
Classification
Cephonic clam class (CEPHALOPODA) is divided into two subclasses: 1. FIRBERCHIA (TETRABRANCHIA); 2. Bunker (Dibranchia).
Subclass four-chamber (Tetrabranchia)
For this purpose, the subclass is characterized by the presence of four gills and a large outer shell separated by partitions on a variety of cameras. The subclass is divided into two detachments: 1. Nautiloidea; 2. Ammonites (ammonoidea).
Nautilids in modern fauna are represented by only one genus - Nautilus, which includes several species. They have a very limited spread in the southwestern part of the Pacific Ocean. Naililids are characterized by many features of a more primitive structure: the presence of a shell, an unreasonable feet funnel, residues of metamers in the form of two pairs of gills, kidneys, atrium, etc. Naililids lived little changed to our time since Paleozoic. These live fossils are the remnants of the once rich fauna of four-chamber challenges. It is known to 2500 fossil species of Nailid.
Ammonites - a fully extinct group of four-sided mollusks that also have a spiral swirling sink. More than 5,000 fossil types of ammonites are known. The rest of their shells are common in Mesozoic sediments.
Dibranchia subclass (Dibranchia)
The bike subclass is characterized by an internal reduced sink (or absence of it); Their respiratory authorities are represented by two gowns. The subclass is divided into two detachments: 1. Tentences (Decapoda); 2. Octopoda.
Detachment Tenntences (Decapoda)
For the tents, the most characteristic presence of 10 tentacles, of which 2 centers, many preserved the rudiment of the shell. Representatives of Craakatitsa (Sepia officinalis), various types of fast floating squids from the genus Ommatostrephes (hundreds of charter's shoes), from the genus Loligo and others.
The rates existed already in Triassa, and possessed the inner, in more developed sink. Founding often in mesozoic sediments from damn fingers "are the balance of the back of the shell of the Mesozoic tensions of Belemnites (Blemnoidea) -telagic animals resembling a squid form.
Octopoda detachment (Octopoda)
Unlike the tenty, it is predominantly benthic animals, with eight tentacles, devoid of shells. Representatives are different types of octopus, as well as Argonauta, etc.
The most important representatives of the clautted clam and their practical importance
Modern cephalopod mollusks are an essential part of the sea and ocean fauna. They are distributed mainly in the southern seas and in the seas with a fairly high salinity. In Russia, most charts in the Far Eastern seas. There are chasonogues and in the Barents Sea. In the Black and Baltic Seas, the cephalopod does not live due to the low salinity of these seas. There are cephalopods at very different depths. Among them are quite a few deep-sea forms. Being predators, cephalopod feed on various marine animals: fish, crustaceans, molluscs, and so. Some of them make great harm, destroying and porting the shoals of valuable fishing fish. Such, for example, Far Eastern squid Ommatostrephes Sloani Pacificus.
Among the charts there are very large forms, up to 3-4 m and more. The largest of famous charts is the deep-water squid (Architeuthis DUX), belonging to the old molluscs. This real giant among cephalopods, and indeed among invertebrates, reaches a length of 18 m, with a length of the tental 10 m and the diameter of each tentacle 20 cm. On similar giants, unfortunately not caught so far in a living form, we know on their remnants , found in the stomachs of the killed tooth whales - coushlots. Many of the teeth whales are feeding with charts, as well as other predators of the seas: sharks, laston-related (seams), etc.
Channels are used in food and man. So, Caracatians and octopuses are used in food by the population of Mediterranean countries. In many countries, Caracatians and squid serve as a fishery.
Channels are the most unusual, the largest and most highly organized of mollusks. A number of unique features are a big activity, a method and speed of movement, an unusually highly developed nervous system, the incarnation of "intelligence", a set of means of protection and attacks - puts challenges of mollusks above all other groups of invertebrates and allows them to compete with spinal animals.
At first glance, the cephalopod - octopuses, Caracatians and squid - do not resemble the rest of the mollusks. They (except Nautilus.) There are no sinks, so typical of soft.
Fig. 22. Squid Wonderful Lycoteuthis Diadema lamp.
The name "cephalopoe" these mollusks were obtained because on the head they have limbs - tentacles, with which many animals can move along the bottom. In addition, it was established that the finiteness of chasisters developed from the legs of an ancient ancestor.
The dimensions of challenges are very different. Among them there are dwarfs, the length of the mantle of which is less than 1 cm and the giants, which belong to squid. The length of their bodies together with tentacles can reach 18 m.
Channel clams - exclusively marine animals. They play a very important role in the life of the ocean. Being predators, they eat a huge amount of crustacean, fish, and, in turn, they themselves serve as food for many marine vertebrates - fish, birds, lastonovy and whales. The most important enemy of charts is a giant teeth whale - Cachelot.
Channel clams - bilateral symmetric animals.
In Caracatians, the torso is flattened, squid - cylindrical, pointed to the rear end, spindle-shaped, octopus - bags. All congorative torso is dressed in a skin-muscular bag - mantia, which concludes internal organs. On the sides of the mantle in squid, Caracatians and pelagic octologists are the fins, which are the most diverse shape and size, and serve molluscs for swimming and as steering. The head of most chasonogues is large, often somewhat wider mantle and separated from her neck interception, but the octopuses have a head with mantia. The head carries the eye, often, especially in deep-water squids, very large, and tentacles, the crown of the surrounding mouth of the mollusk.
The inner surface of the tental (hands) is seated by suction cups. They are located in 1 - 4 (rarely - more) longitudinal rows.
The head side of the head is adjacent, and sometimes a muscular conic tube increases, its base flowing inside the mantle cavity. it funnel, or siphon, the main drivers of the head mollusk, its "jet engine".
Roth hole shapples small. The throat is muscular, equipped with two strong chitinic jaws resembling a parrot beak and called " beak" In the oral cavity on a special linguistic protrusion - odontofore Radules placed - chitinova tape seated by rows of small teeth. With the help of the Radules of the food, which fell into the mouth of the mollusk and moistened with saliva, is transported further into the esophagus. From the pharynx to the stomach stretches a thin tube of the esophagus, piercing on the way to the stomach brain and the liver. Therefore, cephalopod, despite the big appetite, cannot swallow the mining entirely, and they are forced to crush it into small pieces of "beak" before sending it to the mouth. The eaten pieces of food, then fall into a muscular stomach, where digestive juices produced by the liver and pancreas come. The activity of enzymes of these glands is very high, and for 4 hours of food is digested. Suction takes place in a blind stomach process - copume, as well as in the liver. Unpained food residues enter the intestine and thrown out.
In the upper part of the mantle cavity are located gills- one on both sides of the economy.
Blood is driven three hearts – the main thingconsisting of ventricle and two atriality, and two gill. The main heart drives blood over the body, and rhythmic reductions of gill hearts push the venous blood through the gills, from where it enriched with oxygen enters the atrium of the main heart. Heartbeat frequency depends on water temperature. For example, at octopus at water temperature 22 ° C The frequency of the heartbone is 40 - 50 shots per minute.
The cipaths have a circulatory system almost closed: in many places (skin, musculature) there are capillaries through which arteries are transferred to veins.
The blood of challenges of mollusks has a blue color due to the presence of a respiratory pigment in it hemocyanincopper containing. The hemocyanin is produced in special gill glares.
Highly developed blood circulation system makes it possible to achieve gigantic sizes.
Emission bodies serve renal bags, gills of gill hearts and gills themselves. The main product of the shabbing of mollusks - ammonia (more precisely, ammonium ions).
All cepodogs are mollusks - separations. The males of charts usually smallest females, and when ripened one or two hands, they are modified, turning into hetokotil, With the help of which the males during the copulation will carry spermatophores to females seeds.
Speatophores - "Packages" with seed fluid - are difficult to arrange and different species have a different form. Usually, the spermator is a thin, slightly curved tube, in shape resembling a Cossack checker. Spermotoforas are formed in a special department associated with the seed - spermatophore authority; They accumulate in a special storage - a sperm bag. During the pairing of spermatophores through the output channel, it is outwarded, picked up with hectober and transferred to the seed female. In Caracatians and some squids, the seed recipient is located on the rota membrane membrane.
The nervous system in chalp clams is more complicated than the rest of invertebrate animals. According to the degree of complexity, it is not inferior to the nervous system of fish. Ganglia is very closest and essentially form a single nervous mass - a brain, which in intrafanochinny chason, is also concluded in the cartilaginous capsule - skull. According to the relative mass of the brain chasisters, exceeds such fish, but inferior to the brain of birds and mammals.
The brain consists of a fraction, the total number of which at octopus is 64. Optical shares are the largest of them - can be 4/5 of the volume of the brain. According to the subtleties of the senses, the accuracy of perception and complexity of response and behavior of the cephalopy, they are superior to many marine animals. A good memory is characterized by a good memory, and they differ in short-term, intermediate and long-term memory. Octopuses and Cracatites are well trained, and some tasks they decide as successful as rats.
Among the senses of the greatest complexity and perfection were reached. Eyes are usually placed in the deepening of the cartilage head capsule and have a cornea, a rainbow with a soul, crystal and retina, which is capable of narrowing and expanding. There is even an eyelid, as, for example, in squid-onichoteutide, which can close the eyes.
The octopus eye is almost no different from the eye of mammals of animals and man. But there are still differences between them. For example, the cornea of \u200b\u200bthe eye in most chalp clams are not solid, but pierced in front of a small (in Caracatians) or quite wide (at squid) hole. The crystal of the eyes in the puddle is not elliptical, but a round, separated by half a thin epithelial plate. Accommodation of the eye (installation of view on different distances, focusing) in challenges of mollusks is achieved by removing or approaching it to the retina.
No one from the inhabitants of the sea are there are no tearful eyes like in chalk. Only the eyes of Owl, the cats can be competing for them.
And according to the sizes of the eye, the cephalopod mollusks keep the record. The eye of Caracatar is only ten times less than her. At the gigantic squid eyes with the car head. Many deep-water charts have a major part of the head.
On the suction cups of the hands there are tactile and taste receptors. The taste of food cephalopod mollusks is mainly hand. On the rims of the sucker there is a huge amount of mercy-sensitive cells, therefore, each suction cup participates in food tasting.
There are chapatures and sense of smell: squid is papillary, or papillas located on the head of lower eyes, and octopuses have olfactory pits.
In the occipital part of the cartilage skull of chalp clams are two stavocists - equilibrium organs. This is a pair of bubbles filled with liquid and having inside lime pebbles - Statolites. With the slightest change in the position of the body of the Staticites relate to sensitive cells, the walls of the bubble, and the animal is oriented in space.
As for the rumor, it is still unclear whether he has chapal. It is believed that they are blind, and even suggests that deafness is a special adaptation that protects these clams from shock, which can be caused by whale hydrolyators - their worst enemies.
Changage dwells only in the oceans and the polish seas. The content of salts in water should be at least 33 0. Therefore, these mollusks are not found in black or in the Baltic seas. They are extremely numerous in tropical and subtropical waters, but live in moderate waters, and in the polar seas.
Channel clams have long been eaten. In China, Japan and Korea, the use of these animals as food products goes deep into centuries; In Mediterranean countries, it also has a very long history. Antique writers, in particular Aristotle, Plutarch and Pliny, report that in ancient Greece and ancient Rome skillfully cooked octopus was ordinary food. Changs were also used in medicine and perfumery. Of the beautiful shells of nautilos, they made decorations, from the ink liquid Caracatiet sepius made paint and ink.
And so far in the countries of the Mediterranean and Southeast Asia, the cephalopoga is greatly popular. They are harvested in ice cream, fresh, dried and canned form.
Recently, interest in chartoping mollusks increased dramatically. He caused by the unfavorable state of fish stocks and the need to seek additional bioresources that are not used yet by fishing that could fill protein food deficit. Therefore, a whole complex of features puts challenges in the category of valuable fishing animals. According to the main rates of nutritional content - calorie and protein composition - squid and other cephalopions exceed the rest used in food and even some fish and only slightly inferior to beef meat and veal.
To this, the high yield of products should also be added - 80% of the mass of the mollusk is used in food. Moreover, even the internalities of chasters are valuable, as they contain a large number of different substances from which potent drugs can be prepared. Thus, codifications can be used completely, 100%.
Control questions:
What characteristic features of the structure are inherent in mollusks?
What classes shared the type of mollusks?
What are the main signs of the structure are characteristic of the clay clamium?
What building have bivalve mollusks?
What structure have clams of classes of poglong?
What is the meaning of mollusks in nature, human economic activity?
