Protected depths of the Far East. Living Earth - Know Your Home Shellfish are so named because

Slide 14

Akantster

Acanthaster planci or crown of thorns, a large star, 40-50 cm in diameter, is often found on coral reefs of the Pacific and Indian oceans. It is generally accepted that all starfish are completely harmless to humans, but careless handling of acanthaster can cause serious trouble. Numerous short rays extend from the wide flattened disk of the acanthaster. However, young stars have a five-rayed structure typical of most stars, and the number of rays increases only as the star grows. Acantaster is one of the few stars that has not only a large number of rays, but also numerous madrepore plates, the number of which also increases with age. In the largest stars of this type, the number of rays can reach 18-21, and madrepore plates - 16. The entire dorsal surface of the disk and rays is armed with hundreds of large and very sharp needles 2-3 cm long, sitting on movable legs, the ends of which are shaped like a spear tip . For its shape, abundance and sharpness of thorns, this star was called the “crown of thorns”. The color of the crown of thorns can vary from bluish or greenish-gray tones to violet-purple and crimson. Acantaster feeds on coral polyps. The stars crawl among the reefs, leaving behind a white stripe of calcareous coral skeletons with their soft tissues completely eaten away. The variable coloration of the crown of thorns camouflages it well among the bright and varied colors of the coral reef, and the star is not easy to notice at first glance. The crown of thorns is notorious among the inhabitants of many tropical islands. It is impossible to pick it up without receiving stinging injections from sharp needles. Pearl collectors on Tongarewa Atoll in the central Pacific Ocean often have to deal with these stars. The miner writes that if a diver accidentally steps on one of these terrible creatures, the needles pierce the foot and break off, infecting the blood with poisonous secretions. Local residents believe that someone who has received such a wound should immediately use a stick to turn the star over with its mouth side up and press its foot to its mouth. They claim that the star attaches itself to the leg with force and sucks out needle fragments and poison, after which the wounds quickly heal.

In the 60s In our century, on many coral reefs of the islands of the western Pacific Ocean, catastrophic increases in the number of Acantasters were discovered, which led in a number of places to the local destruction of coral reefs. Concerns arose for the fate of some islands, since the living coral reefs that served them as protection from ocean waves began to collapse after the death of the corals. It was necessary to develop urgent measures to combat the acanthaster. The most effective way to destroy stars was by injecting formaldehyde into the star's body with a syringe by scuba divers. In this way, for example, on the reef of the island of Guam, a team of scuba divers destroyed more than 2.5 thousand acanthasters in 4 hours. Various hypotheses have been proposed to explain the reasons for the extraordinary increase in the number of stars. But, apparently, these outbreaks of reproduction of acanthasters are similar to similar outbreaks that periodically occur in some other animals (for example, locusts, silkworms, lemmings, etc.) and then die out (their reasons are not yet fully understood). In the same way, to date, the number of acanthasters has decreased everywhere to the usual norm, and in the areas of coral reefs destroyed by them, restoration and growth of corals has begun.

Slide 15

Anzeropoda

Anseropoda placenta is distributed along the Atlantic coast of Western Europe and in the Mediterranean Sea. Anseropod is a star burrowing into the sand, about 10 cm in diameter, distinguished by an extremely flattened body, the pale pink or bluish surface of which is completely covered with bunches of very small needles. The texture of the surface and the insignificant thickness of the anseropod's body resembles a wafer. Its body is so thin that the upper and lower sides seem to be pressed tightly against each other, without room for any internal cavities. Nevertheless, the anzeropod manages to swallow whole small crabs and hermit crabs, as well as small mollusks and echinoderms.

Slide 16

Patiria comb

Patiria pectinifera, which has the appearance of a regular pentagon, an exceptionally impressively colored small star, is common in the littoral zone of the Sea of ​​Japan. The upper side of this star has bright orange spots scattered against a background of rich pure blue, while the oral side is a uniform fawn color.

Slide 17

Culcita New Guinea

New Guinea Culcita (Culcita novaeguineae) looks like a small pillow. Cultsita is remarkable not only for its unusual shape for stars, but also because in its body cavity a small so-called pearl fish, Carapus, also known under the older name Fieraster, is sometimes found. Karapus usually stays close to some sea cucumbers and, in case of danger, uses their aquatic lungs as a temporary shelter. Apparently, the carp penetrates the culcite when, in case of danger, its usual host is not nearby. But the carp can probably penetrate into the body cavity of a star only by crawling through its mouth into its stomach and then drilling through its wall. It is not yet known whether the fish will be able to escape from such an unusual shelter again.

Slide 18

Linkia

Linckia laevigata is very common in tropical shallow waters of the Pacific and Indian Oceans. It is a bright blue star with five long, almost cylindrical arms. This star and other species of the genus Linckia are very characterized by a special type of asexual reproduction that is not found in other stars. Linkia have the ability to periodically autotomize, that is, spontaneously break off their rays. This process begins with the separation of skeletal plates from each other, most often at a certain distance from the disk. Then the separated part of the arm begins to crawl away from the mother, while still connected to it by soft tissues and skin. Over the course of three to four hours, these tissues stretch more and more (sometimes up to 5 cm) and finally rupture, after which the severed arm begins an independent life. After some time, a new star begins to develop at the site of the break in such an arm, as a result of which the so-called cometary shape of a star is first formed with a group of tiny rays at the end of a single large arm. Subsequently, new rays grow and the star acquires a normal appearance. The mother star grows a new one in place of the severed arm. In places where links are numerous, both comet stars and stars that regenerate one or more arms are often found. If the tip of an autotomized hand is also cut off, sometimes regeneration can begin at both ends and thus two young stars can form, connected by a thick section of the mother's hand.

Slide 19

Asterias

Asterias (Asterias forbesi) has been studied in the most detail and comprehensively, and therefore, using the description of this starfish, one can trace the life of the most typical sea stars. Asterias is a small five-rayed star, the distance between the ends of the opposite rays usually does not exceed 20 cm, but most often stars with a diameter of about 10 cm are found. The color of A. forbesi varies from orange-red to greenish-black tones. A. forbesi feeds mainly on oysters and mussels, but also eats other mollusks, small crustaceans, worms and dead fish, and on occasion attacks living ones, especially sick ones or those entangled in a net. When there is a lack of food in Asterias, cases of cannibalism have also been noted - larger stars eat smaller individuals of their species. Asterias causes great harm to oyster farms. Therefore, American scientists P. Galtsov and V. Luzanov specially devoted a number of years to studying the biology of this star and developing measures to combat it. According to these authors, the gluttony of Asterias is so great that one medium-sized star can destroy several one-year-old oysters every day. At the same time, A. forbesi is very prolific and, under favorable conditions, reproduces in enormous quantities, literally devastating and ruining oyster beds. In the 20s last century, starfish annually destroyed an average of about 500 thousand bushels of oysters off the Atlantic coast of the United States (a bushel is a measure of volume, about 35 liters), which caused losses amounting to about half a million dollars a year. Asterias breeding usually occurs several times during the summer. In this case, even a slight increase in water temperature can serve as a stimulus for the start of reproduction. Stars of both sexes raise their bodies above the bottom at the ends of their rays and sweep their reproductive products into the water through paired holes at the base of each ray. The remnants of the gonads degenerate after the release of reproductive products; in the fall, the formation of new gonads begins, which grow rapidly and by the beginning of next summer are again filled with mature eggs and sperm. The larvae, after three to four weeks of free existence in the water, settle and turn into tiny stars with a diameter of about 1 mm, which soon begin to feed on the young mollusks and other animals that have recently settled to the bottom. Young stars eat each other, as a result of which their numbers greatly decrease in the first month after settling. During their life in plankton, larvae do not travel far from the place where eggs are laid, and the most massive settling of juveniles usually occurs precisely where adult stars are especially numerous.

Slide 21

Astrometis

Astrometis sertulifera prefers to settle in places protected from bright light. This small five-rayed star lives in the shallow waters of the Pacific coast of North America, from California to Vancouver Island. The length of the rays of astrometis usually does not exceed 8 cm. Its dorsal surface is painted in an unusual dark green color and is seated with numerous spines with bright red tips and dark blue or purple bases. The lower surface of the star is straw yellow, and the ambulacral legs are a bright canary color. The bases of the dorsal spines are surrounded by rosettes of numerous small pedicellariae, and larger single pedicellariae are scattered over the surface of the body. According to Jennings' observations, the main purpose of pedicellariae is to protect the delicate skin gills located between the spines. When the surface of the skin is irritated by small crustaceans or other animals crawling onto the star, the papules contract and retract, and the pedicellariae begin to open and close their forceps until they manage to grab the animal that caused the irritation or a foreign particle that has landed on the skin. Pedicellariae can keep captured small crustaceans without releasing them for more than two days. The pedicellariae hold everything they grasp so firmly that it is possible, for example, to lift a star out of the water by the pedicellariae grasping the hairs on the skin of the hand.

Slide 22

Pizaster

Pisaster (Pisaster brevispinus) Very interesting observations were made over this large, predatory five-rayed star. Crawling along the bottom, this star unmistakably stops over the place where one of the mollusks from the genera Saxidomus and Protothaca is located. After this, the star begins to tear up the soil, throwing sand and small pebbles up to 2 cm in size with its legs. This work continues for two or three days, and digging occurs only at night, and during the day the star lies motionless at the site of its excavations. In the end, the star digs a hole equal in diameter to the size of its body (up to 70 cm) and a depth of about 10 cm. Having reached the mollusk, which always ends up in the very center of the hole, just opposite the star’s mouth, the star sticks to the top with its legs located near the mouth shells. Then she lifts, leaning on the ends of the rays, the central part of her body and pulls the mollusk out, after which she deals with it in the usual way for asteriids, opening the shell and sticking her stomach into its cavity. Sometimes stars of the same species from different habitats differ significantly from each other in biology, in particular in their feeding patterns and associated behavior. Thus, pizasters, living off the coast of California, eat mainly flat urchins of the genus Dendraster, and further north, in the Puget Sound, they crawl among the settlements of these urchins, not paying attention to them, and feed on mollusks, digging them up, as described above. Accordingly, the reaction of Dendraster in both regions to the proximity of this star is different. California hedgehogs immediately begin to bury themselves in the sand when a dangerous star creeps near them, and hedgehogs from Puget Sound do not react to stars even at a distance of several centimeters and begin to bury themselves only when disturbed by a star accidentally creeping towards them.

Many other animals also develop defensive reactions to the touch or proximity of predatory stars. Mostly this is a reaction to escape from the star. X. Feder very colorfully describes such a reaction in the large gastropod mollusk abalone (Haliotis). Upon contact with the pizazster, the mollusk lifts the shell on its thick leg and begins to rapidly turn it 180° in one direction or the other. Having freed itself with such shaking movements from the star’s legs attached to the shell, the mollusk turns and crawls away from the predator in a “gait resembling a gallop.” At the same time, its leg sharply contracts and extends, producing movements more characteristic of a leech or a moth caterpillar than a large snail. Gastropod limpets (Astaea) react in a similar way to predatory stars.

Slide 23

Pycnopodia

Pycnopodia (Rusnopodia helianthoides), living on rocky areas of the bottom covered with thickets of brown algae, off the northeastern coast of the Pacific Ocean from California to the Aleutian Islands, is a real giant among starfish. This star has virtually no dorsal skeleton, and its numerous rays are extremely flexible and mobile. The largest stars reach 80 cm in diameter and a mass of 4.5 kg. When such a star crawls, spreading its two dozen rays along the bottom, its body occupies an area of ​​about 0.5 m. The red-brown surface of the body is covered with numerous groups of gray-violet branched papules, between which clusters of pedicellaria are scattered. The well-known expert on sea stars, W. Fisher, describes the behavior of Pycnopodia as follows: “It feeds mainly on sea urchins, hermit crabs and other animals that it manages to catch, attacks large sea cucumbers and eats dead or weakened fish. She catches the latter with her rays, almost as mobile as the arms of an octopus. Excited by the proximity of food, it moves very quickly and is more active than any other star I have ever observed. As this star crawls quickly with its thousands of writhing legs, it makes an imposing impression, and its numerous pom-poms of tenacious pedicellariae and its wide, flexible body make it a formidable weapon of destruction. In the fight against a resisting fish or crab, it can activate more than 15 thousand legs with suction cups. Pycnopodia swallows large sea urchins Strongylocentrotus whole, and after some time throws out the clean shell of the urchin, devoid of spines. After a battle with a sea urchin, the legs of the pycnopodia are abundantly planted with pedicellariae of the urchin, which stand out clearly with their purple color against the light yellow background of the legs. Sometimes pycnopodia even fall into the fishing rods of fishermen, grabbing bait from fish or shellfish meat.” Pycnopodia is interesting not only because of its large size and predatory mode of feeding. This star has secondarily developed some features of bilateral symmetry in addition to those inherited by the stars from their ancestors. The pycnopodium begins its life at the bottom in the form of a small five-rayed star, which soon grows a sixth ray, which, as a rule, occupies a strictly defined position in relation to the interradius with the madrepore plate. A further increase in the number of rays occurs through the formation on both sides of the sixth ray of more and more pairs of symmetrical rays, the number of which can eventually reach 24. Bilateral symmetry also appears in the physiology of the star. The pycnopodia usually moves by directing forward the same specific rays, and uses these same rays primarily to turn over into a normal position if it is placed with its mouth side up.

Slide 24

Evasterias

Evasterias (Evasterias troschelii) Using this star as an example, the way in which starfish manage to open bivalves and eat them has been well studied. Euasterias lives in shallow waters off the Pacific coast of North America. The locking muscle of bivalves of the genus Protothaca was cut, and then their valves were tightened with a rubber belt, which was a kind of dynamometer. By observing how stars eat such mollusks, it was possible to establish that a star with rays 20 cm long can stretch the valves with a force of more than 5 kg. In this case, the star only needs to open the doors a little. Even into a gap a few tenths of a millimeter wide, she is able to insert her stomach, which stretches like rubber. In mussels, at the point where the thin byssal threads emerge from the shell, with which the mollusk is attached to the substrate, there is an unclosable gap about 0.1 mm wide. To push its stomach inside the shell, such an insignificant hole is enough for the star, and in order to feast on the mussel, it does not even have to waste effort on opening the shell. To find out how long a star can stretch its outward-turned stomach, the stars were offered mussels placed inside plastic tubes at different distances from their ends. It turned out that the star is capable of destroying a mussel located 10 cm from the hole, extending its stomach to a distance equal to half the length of the beam, and in some cases to its entire length. It has not yet been definitively clarified whether elasterias secrete any substances that are toxic to mollusks and cause relaxation of the locking muscle. For a number of species, it has been proven that the star opens the shell only through mechanical force. But it is possible that some stars use both methods simultaneously.

Slide 25

Blood star

Blood star (Henricia sanguinolenta), named for its rich red color, is common in the Arctic and North Atlantic Ocean. This star feeds exclusively on various types of sea sponges. At the same time, she can recognize through chemoreception the types of sponges she prefers, even while being at a considerable distance from them.

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Lesson type - combined

Methods: partially search, problem presentation, reproductive, explanatory and illustrative.

Target: mastering the ability to apply biological knowledge in practical activities, use information about modern achievements in the field of biology; work with biological devices, tools, reference books; conduct observations of biological objects;

Tasks:

Educational: the formation of cognitive culture, mastered in the process of educational activities, and aesthetic culture as the ability to have an emotional and value-based attitude towards objects of living nature.

Educational: development of cognitive motives aimed at obtaining new knowledge about living nature; cognitive qualities of a person associated with mastering the fundamentals of scientific knowledge, mastering methods of studying nature, and developing intellectual skills;

Educational: orientation in the system of moral norms and values: recognition of the high value of life in all its manifestations, the health of one’s own and other people; environmental consciousness; nurturing love for nature;

Personal: understanding of responsibility for the quality of acquired knowledge; understanding the value of adequately assessing one’s own achievements and capabilities;

Cognitive: ability to analyze and evaluate the impact of environmental factors, risk factors on health, the consequences of human activities in ecosystems, the impact of one’s own actions on living organisms and ecosystems; focus on continuous development and self-development; the ability to work with various sources of information, transform it from one form to another, compare and analyze information, draw conclusions, prepare messages and presentations.

Regulatory: the ability to organize independent completion of tasks, evaluate the correctness of work, and reflect on one’s activities.

Communicative: the formation of communicative competence in communication and cooperation with peers, understanding the characteristics of gender socialization in adolescence, socially useful, educational and research, creative and other types of activities.

Technologies : Health conservation, problem-based, developmental education, group activities

Types of activities (content elements, control)

Formation in students of activity abilities and abilities to structure and systematize the subject content being studied: collective work - study of text and illustrative material, compilation of a table “Systematic groups of multicellular organisms” with the advisory assistance of student experts, followed by self-test; pair or group performance of laboratory work with the advisory assistance of a teacher, followed by mutual testing; independent work on the studied material.

Planned results

Subject

understand the meaning of biological terms;

describe the structural features and basic life processes of animals of different systematic groups; compare the structural features of protozoa and multicellular animals;

recognize organs and organ systems of animals of different systematic groups; compare and explain reasons for similarities and differences;

establish the relationship between the structural features of organs and the functions they perform;

give examples of animals of different systematic groups;

distinguish the main systematic groups of protozoa and multicellular animals in drawings, tables and natural objects;

characterize the directions of evolution of the animal world; provide evidence of the evolution of the animal world;

Metasubject UUD

Cognitive:

work with different sources of information, analyze and evaluate information, transform it from one form to another;

draw up theses, various types of plans (simple, complex, etc.), structure educational material, give definitions of concepts;

carry out observations, perform elementary experiments and explain the results obtained;

compare and classify, independently choosing criteria for the specified logical operations;

build logical reasoning, including establishing cause-and-effect relationships;

create schematic models highlighting the essential characteristics of objects;

identify possible sources of necessary information, search for information, analyze and evaluate its reliability;

Regulatory:

organize and plan your educational activities - determine the purpose of the work, the sequence of actions, set tasks, predict the results of the work;

independently put forward options for solving assigned tasks, anticipate the final results of the work, choose the means to achieve the goal;

work according to plan, compare your actions with the goal and, if necessary, correct mistakes yourself;

master the basics of self-control and self-assessment for making decisions and making informed choices in educational, cognitive and educational and practical activities;

Communicative:

listen and engage in dialogue, participate in collective discussion of problems;

integrate and build productive interactions with peers and adults;

adequately use verbal means for discussion and argumentation of one’s position, compare different points of view, argue one’s point of view, defend one’s position.

Personal UUD

Formation and development of cognitive interest in the study of biology and the history of the development of knowledge about nature

Techniques: analysis, synthesis, inference, translation of information from one type to another, generalization.

Basic Concepts

General characteristics of the phylum Echinodermata; taxonomy of echinoderms: classes Sea lilies, stars, urchins, class Holothuria, class Ophiura.

During the classes

Updating knowledge ( concentration when learning new material)

Select all correct answers.

1. Mollusks are so named because

A. have an unsegmented body B. have a shell

B. their body is soft D. they move with the help of a muscular leg

2. Eyes are characteristic of representatives of classes

A. bivalves B. gastropods C. cephalopods D. everyone has eyes

3. Respiratory organs of mollusks:

A. body integument B. lungs C. gills D. heart

4. The grape snail belongs to the class

A. bivalves B. cephalopods C. gastropods

5. Cephalopods move

A. with the help of a muscular leg B. with the back end of the body forward

B. in a reactive way D. using tentacles

6. The absence of a head in bivalves is explained by the fact that they

A. have a bivalve shell B. lead a sedentary lifestyle

B. live in water D. move using their legs

7. The octopus releases the contents of the ink sac

A. in case of danger B. during the breeding season

B. during feeding D. in muddy water

8. The internal cartilaginous skeleton of cephalopods develops in connection

A. with the need for support for the muscles B. with the disappearance of the shell

B. with active movement D. with the development of suckers on the tentacles

9. Contraction of the muscle connecting the shell to the body of the gastropod provides:

A. absorption of food B. retraction of the mollusk body into the shell

B. exit of the mollusk body from the shell D. respiration process

C. Divide the shellfish into groups

10. Divide mollusks into groups leading an active or sedentary lifestyle

Groups Representatives

A. active lifestyle 1) mussel 2) pearl barley 3) oyster 4) slug

B. sedentary lifestyle 5) cuttlefish 6) pond snail 7) toothless

8) octopus 9) reel 10) pearl oyster

Learning new material(teacher's story with elements of conversation)

CLASSES: SEA CILLIES, SEA STARS, SEA URCHINES, HOLOTHURIA, BRITISH

1.What makes it possible to combine such dissimilar animals into one type?

2.Are echinoderms found in your area?

General characteristics. TO typeechinoderms, numbering more than 6,500 species, includes animals that live in the seas and oceans, both at great depths and in shallow waters.

The body of echinoderms, from 5 mm to 5 m in length, has ray (radial) symmetry, a calcareous skeleton, often with numerous needles, spines, etc. All echinoderms have a water-vascular system with which they can move, and representatives of some species - touch and even breathe. Slow movement along the bottom is carried out when tube legs, often with suction cups at the ends, are filled with liquid. The body shape of echinoderms is very diverse. There is no division of the body into sections. Echinoderms are usually dioecious. They have a high ability to regenerate.

TypeEchinoderms. Lessonbiology

Class Sea lilies. Among sea lilies there are sessile and free-swimming forms. The mouth opening of these echinoderms opens in the upper part of the body. All crinoids feed on small planktonic organisms. They breathe through the surface of the body. There are usually 5 tentacles, but they can branch up to 200 or more processes.

Sea lily

Starfish class. These are sedentary animals with from 5 to 50 rays. Their mouth opening is on the underside of the body. Sea stars feed mainly on dead animals, as well as mud and sedentary animals. Some predatory starfish destroy commercial mollusks. The stomach of these echinoderms can evert out through the mouth opening and envelop the prey.

Among the starfish there are both hermaphrodites and dioecious ones. Reproduction is asexual and sexual.

The fertility of sea stars can vary: per individual from several tens to 200 million eggs. In the shallow waters of the northern seas, starfish freeze in winter and thaw in spring.

Marinestars

Class Sea urchins. Freely moving animals with a hard shell covered with movable spines. Representatives of some species can move along the bottom with their help. The mouth is equipped with a gnawing apparatus and is located on the underside of the body. They feed on algae, sessile animals, and mud. One female lays up to 20 million eggs.

Some species of sea urchins take care of their offspring: they carry eggs and young on their bodies.

NauticalhedgehogVseaGreece

Class Holothuria, or Sea Cucumbers. The body of these animals shrinks greatly when touched and becomes like a cucumber. Sea cucumbers, which are classified as sea cucumbers, are edible; they are caught and even specially bred. The body length of holothurians usually ranges from a few millimeters to 2 m. The mouth is located at the anterior end of the elongated body. Holothurians feed mainly on animals living on the surface of silt, plants and their remains.

Almost all sea cucumbers are dioecious, but hermaphrodites are also found. Some species of these echinoderms show care for their offspring. One female lays up to 77 million eggs.

Holothurians live in the seas at various depths and are little sensitive to salinity. An amazing feature of them is their adaptability to protection from enemies and other dangers. By strongly contracting, the sea cucumbers eject their entrails through the anus, which are subsequently restored.

Galaturia, ornauticalcucumber

ClassBrittle stars. Flat, freely moving echinoderms, up to 10 cm in diameter and with long, sometimes branching rays. Brittle stars move by lifting their body above the ground with the help of rays. By extending branched rays, brittle stars catch and capture small planktonic organisms, filtering the water.

Brittle stars are mostly dioecious, but some are hermaphrodites and reproduce asexually.

There are brittle stars living on other echinoderms (hedgehogs, lilies), as well as on sponges and corals. Some of the brittle stars can glow. Many have developed the ability to regenerate.

Ophiura. Redsea.

Echinoderms are capable of regeneration after self-mutilation with tentacles and rays.

Sea cucumber meat contains 100 times more iodine than any other marine invertebrate, and 10 thousand times more than beef. In addition, the body of sea cucumbers contains chlorine and sulfur, phosphorus and calcium, manganese and magnesium, cobalt and many other elements necessary for the human body to develop normally.

Starfish are the longest-lived echinoderms: they live up to 20 years. Some of them can survive after starvation for up to 1.5 years or freezing in shallow water.

Independent work

1.Make a general description of the type Echinoderms according to plan

Habitat

Symmetry:

Body shape and size

Features of the external structure

Features of the internal structure

Sense organs

Circulatory system

Digestive system

Excretory system

Nervous system

Reproduction method

2.Fill out the table

3.Fill out the diagram

Answer the questions

Why did echinoderms manage to populate all seas and oceans in deep and shallow waters?

By what characteristics did the phylum of echinoderms and its classes get their names?

What is the significance of echinoderms?

Resources

Biology. Animals. 7th grade textbook for general education. institutions / V.V. Latyushin, V.A. Shapkin.

Active formsAndbiology teaching methods: Animals. Kp. for the teacher: From work experience, -M.:, Education. Molis S. S.. Molis S. A

Work program in biology 7th grade for teaching materials V.V. Latyushina, V.A. Shapkina (M.: Bustard).

V.V. Latyushin, E. A. Lamekhova. Biology. 7th grade. Workbook for the textbook by V.V. Latyushina, V.A. Shapkina “Biology. Animals. 7th grade". - M.: Bustard.

Zakharova N. Yu. Tests and tests in biology: to the textbook by V. V. Latyushin and V. A. Shapkin “Biology. Animals. 7th grade” / N. Yu. Zakharova. 2nd ed. - M.: Publishing house "Exam"

Presentation hosting

They raise many questions, among which the following are of particular interest: “What does a starfish eat?”, “For whom does it pose a mortal threat?”

Stars on the seabed

These extraordinary decorations of the seabed have existed on the planet for quite a long time. They appeared about 450 million years ago. There are up to 1600 types of stars. These animals inhabit almost all seas and oceans of the earth, the water of which is quite salty. Stars do not tolerate desalinated water; they cannot be found in the Azov and Caspian Seas.

Animals can have rays from 4 to 50, sizes range from a few centimeters to a meter. The lifespan is about 20 years.

The sea inhabitants do not have a brain, but on every ray there is an eye. The organs of vision resemble insects or crustaceans and distinguish between light and shadow well. Many eyes help animals hunt successfully.

Stars breathe almost through their skin, so it is very important for them to have a sufficient amount of oxygen in the water. Although some species can live at decent depths of the ocean.

Structural features

It is interesting how starfish reproduce and feed. Biology classifies them as invertebrate echinoderms. The starfish does not have blood as such. Instead, the star's heart pumps sea water enriched with certain microelements through its vessels. Pumping water not only saturates the animal's cells, but also by forcing fluid into one place or another helps the star move.

Starfish have a ray structure of the skeleton - rays extend from the central part. The skeleton of sea beauties is unusual. It consists of calcite and develops inside a small star from almost a few calcareous cells. What and how starfish feed largely depends on the characteristics of their structure.

These echinoderms have special pedicellaria on their tentacles in the form of tweezers at each tip of the outgrowth. With their help, the stars hunt and clean their skins from debris clogged between the needles.

Cunning hunters

Many people are interested in how starfish eat. A brief description of the structure of their digestive system can be found below. These amazing beauties create the impression of complete security. In fact, they are sea predators, voracious and insatiable. Their only drawback is their low speed. Therefore, they prefer a stationary delicacy - mollusk shells. The starfish eats scallops with pleasure, and is not averse to eating sea urchins, sea cucumbers, and even fish that carelessly swim too close.

The fact is that the starfish has practically two stomachs, one of which can turn outward. An unwary prey, captured by the pedicellariae, is transferred to the mouth opening in the center of the rays, then the stomach is thrown over it like a net. After this, the hunter can release the prey and slowly digest it. For some time, the fish even drags its executioner along with it, but the victim can no longer escape. Everything that a starfish eats is easily digested in its stomach.

She acts somewhat differently with shells: she slowly approaches the dish she likes, entwines the shell with her rays, places her mouth opening opposite the slit of the shell and begins to move the shells apart.

As soon as even a small gap appears, the external stomach is immediately pushed into it. Now the sea gourmet calmly digests the owner of the shell, turning the mollusk into a jelly-like substance. This fate awaits any eaten victim, no matter whether the starfish feeds on a scallop or a small fish.

Features of the structure of the digestive system

The predator does not have any devices for capturing prey. The mouth, surrounded by a ring lip, connects to the stomach. This organ occupies the entire interior of the disc and is highly flexible. A gap of 0.1 mm is enough to penetrate the shell doors. In the center of the aboral side, a narrow, short intestine opens, extending from the stomach. What a starfish eats largely depends on the unusual structure of its digestive system.

Love of the stars at the bottom of the ocean

Most starfish are heterosexual. During love games, individuals are so busy with each other that they stop hunting and are forced to fast. But this is not fatal, because in one of the stomachs these cunning creatures try to deposit nutrients in advance for the entire duration of mating.

The gonads are located in stars near the base of the rays. When mating, the female and male individuals connect the rays, as if merging in a tender embrace. Most often, eggs and male reproductive cells end up in sea water, where fertilization occurs.

If there is a shortage of certain individuals, stars can change sex to maintain the population in a certain area.

These eggs are most often left to their own devices until the larvae hatch. But some stars turn out to be caring parents: they carry eggs and then larvae on their backs. For this purpose, in certain species of starfish, during mating, special sacs for eggs appear on their backs, which are well washed with water. There she can remain with the parent until the larvae appear.

Reproduction by division

A completely extraordinary ability of starfish is reproduction by fission. The ability to grow a new ray arm exists in almost all animals of this species. A star grabbed by a beam by a predator can throw it away like a lizard's tail. And after a while, grow a new one.

Moreover, if a small particle of the central part remains on the beam, after a certain time a full-fledged starfish will grow from it. Therefore, it is impossible to destroy these predators by cutting them into pieces.

Who are starfish afraid of?

Representatives of this class have few enemies. Nobody wants to mess with the poisonous needles of sea celestials. Animals are also able to secrete odorous substances to scare away particularly voracious predators. In case of danger, the star can bury itself in silt or sand, becoming almost invisible.

Among those who feed on starfish in nature, large seabirds predominate. On the shores of warm seas they become prey for seagulls. In the Pacific Ocean, cheerful sea otters are not averse to feasting on the star.

Predators harm underwater plantations of oysters and scallops - what the starfish eats. Attempts to kill animals by cutting them into pieces led to an increase in the population. Then they began to fight them, bringing the stars ashore and boiling them in boiling water. But there was nowhere to use these remains. There have been attempts to make fertilizer from animals that also repels pests. But this method was not widely used.

OCTOPUS

He lives at the very bottom
At a terrible depth -
Many-armed,
multi-legged,
Nogoruky,
Armed.
Goes to sea without boots
Octopus Kalmarych Octopus!
(G. Kruzhkov)
Octopuses do not have a hard skeleton. Its soft body has no bones and can bend freely in different directions. The octopus was named so because eight limbs extend from its short body. They have two rows of large suction cups, which the octopus can use to hold prey or attach to rocks at the bottom.
Octopuses live near the bottom, hiding in crevices between rocks or in underwater caves. They have the ability to change color very quickly and become the same color as the ground.
The only hard part of an octopus's body is its horny beak-like jaws. Octopuses are true predators. At night they get out of their hiding places and go hunting. Octopuses can not only swim, but also move along the bottom by rearranging their tentacles. The usual prey of octopuses are shrimp, lobsters, crabs and fish, which they paralyze with poison from the salivary glands. With their beak they can break even the strong shells of crabs and crayfish or shells of mollusks. Octopuses take their prey to a shelter, where they slowly eat it. Among octopuses there are very poisonous ones, the bite of which can be fatal even to humans.
Octopuses often build shelters from stones or shells, using their tentacles like hands. Octopuses guard their home and can easily find it even if they have gone far away. For a long time, people have been afraid of octopuses (octopuses, as they called them), writing terrible legends about them. The ancient Roman scientist Pliny the Elder talked about a giant octopus - polypus, which stole fishing catches. Every night the octopus climbed onto the shore and ate the fish lying in the baskets. The dogs, smelling the octopus, started barking. The fishermen who came running saw the octopus defending itself from the dogs with its huge tentacles. The fishermen had difficulty coping with the octopus. When the giant was measured, it turned out that its tentacles reached a length of 10 meters, and its weight was about 300 kilograms.
MYSTERY
Don't you know me?
I live at the bottom of the sea,
Head and eight legs -
That's all I am... (octopus).

STARFISH

A star fell from the sky,
She fell into the ocean.
And now it's there all year round
Slowly crawling along the bottom.
(V. Moroz)
The starfish is a predator that lives on the ocean floor. Typically these animals are shaped like a star with five rays. Brightly colored sea stars crawl slowly along the bottom or burrow into the mud. They feed on mollusks, sea cucumbers, brittle stars and sea urchins. The starfish's mouth is located on the underside of its body, so in order to eat its prey, the starfish crawls on top of it.
Starfish have the amazing ability to open the shells of oysters or mussels with their strong rays. Some stars don't even need to open their shells completely. They turn their stomach inside out through their mouth and push it into the hole in the shell. The shellfish is digested right in the shell. Having digested the prey, the star retracts its stomach.
In case of danger, starfish, like lizards, can throw away part of their body. But a new lizard will not grow from a discarded tail. In a starfish, on the contrary, a new animal grows from any part of its body. Scientists conducted experiments - they cut a starfish into several parts. After some time, each part turned into a starfish.
Starfish are relatives of sea urchins. The starfish Asterias even has a calcareous skeleton, and small needles stick out from under the skin. Another species of starfish, accancasters, are similar to sea urchins - their arms and backs are covered with long and poisonous spines. Accancasters cause great damage to coral colonies by eating them.
Some starfish feed on their relatives. For example, crossasters. These huge starfish have 12 arms and grow to almost half a meter in diameter. They are able to move quickly along the bottom and catch up with slower starfish. Crossasters themselves may feel safe because they have poisonous bodies.

SEA URCHIN

Like a cactus on the window
The sea urchin grows on the bottom.
A flounder swam by
I poured some water on him.
(Yu. Parfenov)
It turns out that hedgehogs live not only on land. There are also sea urchins. They are not relatives of land urchins, but belong to the class of invertebrate animals such as echinoderms.
The outside of the sea urchin's body is covered with a shell from which numerous spines protrude. The needles are very thin and sharp, with serrations at their ends. If such a needle sticks into a person’s skin, it is very difficult to remove it. Sea urchins are poisonous, and if injected, a person will feel a burning pain.
With the help of needles, sea urchins not only protect themselves from enemies, but also move, as if on stilts, along the seabed. The spear-bearing sea urchin moves at high speed, one might even say that it does not walk, but runs.
Small fish use sea urchin spines for protection. They make themselves a safe hiding place between the needles. In gratitude for the fact that the hedgehog protects them, the fish clean its shell. These fish acquire the same color as the color of their “host” - the sea urchin. At night, the fish leave their shelter for a short time, and in case of danger they hide again between the needles.
Despite their terrifying appearance, sea urchins are often defenseless. Their main enemy is starfish. They can stick their stomach between the needles and digest the hedgehog from the outside.
Large snails living in the Mediterranean Sea have invented an unusual way of hunting sea urchins. They spit on their prey! The saliva of these snails contains hydrochloric acid, which paralyzes the hedgehog and corrodes its shell.
Some predatory fish release a strong stream of water from their mouths at the hedgehog. The sea urchin turns over with its unprotected belly up and becomes easy prey.
MYSTERY
Looks like a prickly ball
Lives deep at the bottom.
(Sea urchin)

JELLYFISH

Transparent jellyfish
Floats quietly.
If you touch a jellyfish -
It'll burn you like an electric shock!
(N. Migunova)
Jellyfish are close relatives of sea anemones and corals. Unlike these animals, they do not spend their entire lives attached to rocks, but rather swim freely in the sea.
Jellyfish have a translucent, umbrella- or bell-shaped body, similar to jelly. These animals swim by rhythmically contracting their umbrella and pushing water out from under it. They capture prey using tentacles.
The tentacles of jellyfish contain stinging cells that can burn the enemy or even paralyze him. The venom contained in the stinging cells of the small cross jellyfish can cause fatal burns in humans.
Another jellyfish, the sea wasp, is also dangerous to humans. It looks like an inverted deep bowl, from which twenty tentacles 10 meters long stretch down. They contain large amounts of poison.
Jellyfish feed on plankton, small crustaceans and fish.
Jellyfish come in different sizes, from a few millimeters to several meters. The largest jellyfish lives in the northern seas - the polar jellyfish. The length of its tentacles reaches 30 meters, and the diameter is two meters.
Jellyfish about the sea
Writes poetry
But only about this
Nobody will know
She has no hands
To hold a pen,
She has no mouth
To read out loud.
The jellyfish composes for herself,
Her silent muse is sad.
(I. Zhukov)
Jellyfish live not only on the surface of the ocean, but also in the depths of the sea. Deep-sea jellyfish can glow in the dark. Small crustaceans swim into the light of this living lantern, right into the tentacles of the insidious jellyfish.
Other jellyfish are also glowing. The umbrella and tentacles of the pelagia jellyfish glow with a yellow-orange light. If many Equiorian jellyfish living off the Pacific coast of America rise to the surface, it seems that the whole sea is burning with red fire.