Sea urchins and starfish. Presentation on the topic "Sea urchins and starfish". Features of the structure of the digestive system

lesson type - combined

Methods: partially exploratory, problem presentation, reproductive, explanatory-illustrative.

Target: mastering the skills to apply biological knowledge in practical activities, to 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 a cognitive culture, mastered in the process of educational activities, and aesthetic culture as an ability to have an emotional and value attitude towards objects of wildlife.

Developing: development of cognitive motives aimed at obtaining new knowledge about wildlife; cognitive qualities of the individual associated with the assimilation of the basics of scientific knowledge, mastering the methods of studying nature, the formation of 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; ecological consciousness; education of love for nature;

Personal: understanding of responsibility for the quality of acquired knowledge; understanding the value of an adequate assessment of one's own achievements and capabilities;

cognitive: the 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, convert it from one form to another, compare and analyze information, draw conclusions, prepare messages and presentations.

Regulatory: the ability to organize independently the execution of tasks, evaluate the correctness of the work, reflection of their activities.

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

Technology : Health saving, problematic, developmental education, group activities

Activities (elements of content, control)

Formation of students' activity abilities and abilities to structure and systematize the studied subject content: collective work - study of the text and illustrative material, compilation of the table "Systematic groups of multicellular organisms" with the advisory assistance of expert students, followed by self-examination; pair or group performance of laboratory work with the advisory assistance of a teacher, followed by mutual verification; independent work on the studied material.

Planned results

subject

understand the meaning of biological terms;

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

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

to establish the relationship between the features of the structure of organs and the functions that they perform;

give examples of animals of different systematic groups;

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

characterize the direction of evolution of the animal world; give evidence of the evolution of the animal world;

Metasubject UUD

Cognitive:

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

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

make observations, set up elementary experiments and explain the results obtained;

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

build logical reasoning, including the establishment of 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 their educational activities - determine the purpose of the work, the sequence of actions, set tasks, predict the results of work;

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

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

own the basics of self-control and self-assessment for making decisions and making a conscious choice in educational and cognitive and educational and practical activities;

Communicative:

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

integrate and build productive interaction with peers and adults;

adequately use speech 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

Receptions: analysis, synthesis, conclusion, transfer of information from one type to another, generalization.

Basic concepts

General characteristics of the type Echinoderm; taxonomy of echinoderms: classes Sea lilies, stars, hedgehogs, Holothuria class, Ophiura class.

During the classes

Knowledge update ( concentration of attention when learning new material)

Select all correct answers.

1. Mollusks are so named because

A. have a non-segmented body B. have a shell

C. 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. all have eyes

3. Respiratory organs of molluscs:

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

4. 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

C. in a reactive way D. with tentacles

6. The absence of a head in bivalves is due to the fact that they

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

B. live in water D. move with their feet

7. The octopus releases the contents of the ink bag

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

V. in the process of feeding G. in troubled 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

V. with active movement G. with the development of suckers on the tentacles

9. The contraction of the muscle connecting the shell to the body of the gastropod mollusk provides:

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

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

C. Divide the shellfish into groups

10. Divide the mollusks into groups leading a mobile or sedentary lifestyle

Groups Representatives

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

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

8) octopus 9) coil 10) pearl

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

CLASSES: SEA LILYS, SEA STARS, SEA URGUNS, HOLOTHURIANS, OFIURES

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

2. Are there echinoderms in your area?

General characteristics. To typeechinoderms, numbering more than 6500 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 long, has radial (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 the tubule legs are filled with liquid, often with suction cups at the ends. The body shape of echinoderms is very diverse. There is no division of the body into sections. Echinoderms usually have separate sexes. They have a high ability to regenerate.

TypeEchinoderms. Lessonbiology

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

Sea lily, Sea Lily

Class Starfish. These are sedentary animals, having from 5 to 50 rays. Their mouth opening is on the underside of the body. Starfish feed mainly on dead animals, as well as silt and sedentary animals. Some predatory starfish destroy pro thought mollusks. The stomach of these echinoderms can invert through the mouth opening and envelop the prey.

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

The fecundity of sea stars can be different: for one 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. Free-moving animals with a hard shell covered with movable spines. Representatives of some species can use them to move along the bottom. The mouth is equipped with a gnawing apparatus and is located on the underside of the body. They feed on algae, sedentary animals, silt. One female spawns up to 20 million eggs.

In sea urchins of certain species, care for offspring is observed: they bear eggs and juveniles on the body.

NauticalhedgehoginseaGreece

Class Holothuria, or Sea cucumbers. The body of these animals shrinks strongly when touched and becomes like a cucumber. Sea cucumbers related to holothurians are edible, they are caught and even specially bred. The body length of holothurians is usually 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 holothurians have separate sexes, but there are hermaphrodites. Some species of these echinoderms take care of their offspring. One female spawns up to 77 million eggs.

Holothurians live in the seas at various depths and are not very sensitive to salinity. Their amazing feature is their ability to protect themselves from enemies and other dangers. Strongly squeezing, holothurians throw out their insides through the anus, which are subsequently restored.

Galaturia, ornauticalcucumber

ClassOfiury. Flat, free-moving echinoderms, up to 10 cm in diameter and with long, sometimes branching rays. The brittle stars move, lifting the body above the ground with the help of rays. Stretching branched rays, brittle stars catch and capture, filtering water, small planktonic organisms.

The ophiurs are mostly dioecious, but there are also hermaphrodites, and they reproduce asexually.

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

Ofiura. Redsea.

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

Trepang meat contains 100 times more iodine than any other marine invertebrate, and 10,000 times more than beef. In addition, the body of trepangs contains chlorine and sulfur, phosphorus and calcium, manganese and magnesium, cobalt and many other elements necessary for the human body for normal development.

Sea stars are long-lived among echinoderms: they live up to 20 years. Some of them can survive after starving for up to 1.5 years or freezing in shallow water.

Independent work

1.Make a general description of the type of Echinoderm according to the 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 in the table

3.Fill in the chart

Answer the questions

Why did echinoderms manage to populate all the seas and oceans at depths and shallow waters?

On what grounds did the type of echinoderms and its classes get their names?

What is the meaning of echinoderms?

Resources

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

Active Formsandbiology teaching methods: Animals. Kp. for the teacher: From work experience, —M.:, Enlightenment. Molis S. S. Molis S. A

Work program in biology grade 7 to the teaching materials of 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. Shapkin "Biology. Animals. 7th grade". - M.: Bustard.

Zakharova N. Yu. Control and verification work in biology: to the textbook by V. V. Latyushin and V. A. Shapkin “Biology. Animals. Grade 7 "/ N. Yu. Zakharova. 2nd ed. - M.: Publishing house "Exam"

Presentation Hosting

10. SEA urchins, stars, lilies and holothurians

To what amazing animals live at the bottom of the sea! They don't have a right or left side. They can crawl in all directions and in each direction they move forward. They are called echinoderms. There are thousands of lime plates in their body. This external skeleton protects animals that are slow in their movement. Many, like sea urchins, are still protected by a mass of needles sticking out in all directions. The sea urchin calmly crawls along the bottom, not being afraid of voracious predators. It has the shape of a slightly flattened ball, on which there are five rows of thin transparent sucker legs. With the help of these legs, the sea urchin slowly crawls along the bottom with its mouth down.

The starfish is either a pentagon or a five-pointed star. There are also multiple stars. Along the lower surface of the rays of the star protrude five rows of the same transparent sucker legs, like those of a hedgehog. But the hedgehog is a peaceful animal, and the star is a predator. In pursuit of prey, she must move quickly. Her mobile rays come to her aid. Quickly bending and unbending its rays, the star moves in search of food. Often she attacks animals that are larger than her size, which she cannot swallow. Then the star throws out the stomach, envelops the caught prey with it, digests it, and then draws the stomach into the body. There are enemies and the starfish. A predatory fish will catch it, bite off one or more rays. Another animal would have died from such an operation. But the star not only survives, it quickly grows new rays to replace those torn off. This ability to repair damaged body parts perfectly protects the starfish from death.

Swaying on a thin stem, similar to a flower, a sea lily lives at the bottom of the sea. This is not a plant, but an animal, but only it grows to the ground. At great depths, where waves do not reach, there is no need for strong supports. You can live on a thin leg. Spreading its arms, which serve it not to grasp the passing prey, but to create a current of water that drives small organisms floating in the water into its mouth, the sea lily feels great at the bottom of the sea.

Echinoderms also include bag-shaped holothurians or, as they are also called for their body shape, sea cucumbers. By the presence of small calcareous bodies in the skin, along five rows of legs, we see that holothurians are relatives of sea urchins, stars and lilies. They crawl on rocks, dig in sand and silt. There are always many remains of dead animals and plants in the silt. They feed on holothurians. Among the holothurians there is a very valuable breed in terms of commercial use, called trepang. Trepang lives at the bottom of our Far Eastern seas. In China, trepang is valued as a tasty dish. Large batches of these holothurians in dried form are sent to China and other countries of the Far East.

Echinoderms are very ancient animals. In the deepest layers of the earth, you can find the imprints of sea urchins, lilies and stars. Among them there are forms that are not among those living today. But there are also those who live today.

Echinoderms are real marine animals, they are not at all not only in fresh water, but even in slightly salty seas.

To there are no fish in the sea! In some, the body, like a torpedo, is elongated. Others are flat and lie at the bottom of the sea. There are fish long like snakes and round like balls. All this variety of forms is connected with the way of life of fish. Once upon a time, fish were not the same as they are now. The living conditions in the seas changed, and the appearance and organs of the body of fish changed. They became more diverse and more and more different breeds appeared. Fish began to live not only in warm seas, but also in cold ones.

Some fish eat where they live. Others hunt for fleeing prey. Still others make huge journeys in search of food. Fry often live in the surface layer of water, and adults at great depths. Herrings spend their whole lives in the water column, and lay their eggs on the bottom. Most fish live their entire lives in the sea. Some enter to spawn in rivers. It is difficult to describe the diversity of the fish population of the sea.

The fish are of great commercial importance. Fishing is the richest branch of the national economy. Thousands of ships come from the sea, loaded with a rich catch. Hundreds of factories on the shore freeze, salt, smoke fish or make canned food from it. Fish meat is very tasty and nutritious, fish oil saves children from rickets - it contains a lot of vitamins. Heads and bones are used to make fishmeal, a good pet food. Even the skin of fish finds use.

We hear a lot of stories about sharks. These are excellent swimmers, voracious predators. One appearance of them causes a commotion in the school of fish. The body of a shark, elongated in length, is like a torpedo. It is wider at the head than at the tail, and easily cuts through the water. The strong tail serves as the main organ of movement. The shark can reach speeds of up to 20 kilometers per hour. Usually sharks have a size of 2-4 meters. Sharks are predatory. You have to be very nimble or inconspicuous (disguised) to escape from the sharp teeth of a voracious fish. It happens that sharks attack humans. There are real giants among sharks, reaching 30 meters in length, but these sharks are peaceful inhabitants of the sea. They feed on small crustaceans that develop in huge numbers in the seas. Such a shark will swim into a huge flock of crustaceans and sip water. All this little thing remains in her mouth. Each crustacean weighs a milligram (1/1000 of a gram), and millions and billions of these crustaceans are quite capable of feeding a giant shark.

Other fish predators, hunting for food, resort to cunning. Quietly lies at the bottom among the stones a fish called "sea devil". A mustache moves on his head. Some fish will pounce on an imaginary worm and end up in the huge mouth of the sea devil. And you don’t have to swim, and food goes into your mouth by itself!

To disguise yourself, to become invisible, is very beneficial in that ongoing war that is being waged in the depths of the sea. Among the stones, quite pressed to the bottom, lies a flat fish flounder. The upper part of her body is painted to match the color of the surrounding soil. She is not visible at all. Moreover, the flounder will swim from sandy to rocky soil and its color and location of spots on the body will immediately change. On sandy soil, the pattern is small, on rocky soil it will become spotty. The skin of the flounder has special colored cells that can rise to the surface or sink into the depths of the skin. With the help of these cells, the pattern and color of the flounder's skin quickly changes when it gets from one soil to another. This is how a defenseless flounder is saved from its enemies. A shark swam, darted in different directions, examined the bottom with a keen eye and found nothing. Everything hid, disguised itself, as if the turbulent life had not been here a minute ago.

Among the branches of corals, colorful small fish swim, somewhat reminiscent of butterflies in their color and body shape. Variegated, brightly colored, they catch the eye in the aquarium, but become completely invisible among a variety of corals. Military cloakers could learn a lot from coral reef fish. What military science has come to has developed in these fish for a long time in the struggle for existence.

What is this strange phenomenon? Like a flock of sparrows fluttered from the wave and scattered in different directions. They flew several tens of meters, barely touched the wave and quickly flew on. Some of them even flew onto the deck of the ship. These are wonderful silvery fish, whose pectoral fins have turned into wings. How many progenitors of these flying fish died from generation to generation until their fins developed into wings, allowing them to fly away from the chase for a hundred meters. This is beneficial to them also because the enemy loses the direction of the chase. But the wing of a fish is not the wing of a bird, but of an airplane. A flying fish does not flap its wings. Fleeing from the pursuer, the fish quickly swims, working with its tail, to the surface of the sea. Wings-fins are pressed to the sides of the body, the whole body is directed upwards. Finally, the fish reached the surface. Like a real hydroplane, it quickly takes off, then spreads its wings against the oncoming air flow and takes off. She flies in the air like a glider. "Motor" - her tail, he worked in the water. If you need to fly further, the fish will touch the wave, pick up speed again and take off again.

OCTOPUS

He lives at the bottom
At a terrible depth -
many-armed,
many-legged,
Nogoruky,
Armed.
Walks in the sea without boots
Octopus Kalmarych Octopus!
(G. Kruzhkov)
Octopuses do not have a hard skeleton. Its soft body has no bones and can freely bend in different directions. The octopus was named so because eight limbs extend from its short body. They have two rows of large suction cups, with which the octopus can hold prey or attach to the stones at the bottom.
Octopuses live at the bottom, hiding in crevices between stones 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 the body of octopuses is the horny beak-like jaws. Octopuses are real predators. At night, they get out of their hiding places and go hunting. Octopuses can not only swim, but also, by rearranging their tentacles, walk along the bottom. 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 even break the strong shells of crabs and crayfish or mollusk shells. The octopus takes the prey to the shelter, where they slowly eat it. Among the octopuses there are very poisonous ones, the bite of which can be fatal even for humans.
Often, octopuses build shelters from stones or shells, while wielding their tentacles as if they were hands. Octopuses guard their home and can easily find it even if they are far away. Since ancient times, people have been afraid of octopuses (octopuses - as they called them), writing terrible legends about them. The ancient Roman scientist Pliny the Elder spoke about a giant octopus - a polypus that stole fishing catches. Every night the octopus got out on the shore and ate the fish lying in the baskets. The dogs, smelling the octopus, started barking. The fishermen who came running saw how the octopus defended itself from the dogs with its huge tentacles. The fishermen struggled 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
Are you not familiar with 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 got 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 at the bottom of the ocean. Usually these animals are shaped like an asterisk with five rays. Brightly colored starfish slowly crawl along the bottom or burrow into the silt. They feed on molluscs, holothurians, brittle stars and sea urchins. The mouth of a starfish is located on the underside of the body, therefore, in order to eat prey, a starfish crawls on top of it.
Starfish have an amazing ability to open the shells of oysters or mussels with their strong rays. Some stars don't even need to fully open their shells. They turn their stomach inside out through their mouths and push it into the hole in the shell. The mollusk is digested right in the shell. Having digested the prey, the star draws the stomach back.
In case of danger, starfish, like lizards, can throw off 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 the body. Scientists conducted experiments - they cut a starfish into several parts. Each part after a while turned into a starfish.
Sea stars are relatives of sea urchins. The starfish asterias even has a calcareous skeleton, and small needles stick out from under the skin. Another variety of starfish, acancasters, are similar to sea urchins - their rays and backs are covered with long and poisonous spines. Acancasters cause great damage to coral colonies by eating them.
Some starfish feed on their relatives. For example, crossovers. These huge starfish have 12 rays 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 at the bottom.
The flounder swam
Poured him with water.
(Yu. Parfenov)
It turns out that hedgehogs live not only on land. There are also sea urchins. They are not relatives of land hedgehogs, but belong to the class of invertebrate animals such as echinoderms.
Outside, the body of the sea urchin is covered with a shell, from which numerous needles protrude. The needles are very thin and sharp, with notches at their ends. If such a needle sticks into the skin of a person, it is very difficult to remove it. Sea urchins are poisonous, and, having pricked, a person will feel a burning pain.
With the help of needles, sea urchins not only protect themselves from enemies, but also move, like on stilts, along the seabed. The spear-bearing sea urchin moves at great speed, one might even say that it does not walk, but runs.
Small fishes use sea urchin spines for protection. They make 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 "master" - the sea urchin. At night, the fish briefly leave their shelter, and in case of danger they again hide between the needles.
Despite their intimidating 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! In the saliva of these snails there is hydrochloric acid, which paralyzes the hedgehog and corrodes its shell.
Some predatory fish release a strong jet of water into the hedgehog from their mouths. The sea urchin rolls over with its unprotected belly up and becomes easy prey.
MYSTERY
Looks like a spiny ball
Lives deep at the bottom.
(Sea urchin)

JELLYFISH

transparent jellyfish
Floats a little.
Touch the jellyfish -
How electric it will burn!
(N. Migunova)
Jellyfish are close relatives of sea anemones and corals. Unlike these animals, they do not spend their whole lives attached to stones, but swim freely in the open sea.
Jellyfish have a translucent body in the shape of an umbrella or a bell, similar to jelly. These animals swim by rhythmically contracting the umbrella and pushing water out from under it. They capture prey with the help of tentacles.
On the tentacles of jellyfish are stinging cells that can burn the enemy or even paralyze him. The poison contained in the stinging cells of a small cross jellyfish can cause fatal burns in humans.
Another jellyfish, the sea wasp, is also dangerous for humans. It looks like an inverted deep bowl, from which twenty tentacles 10 meters long stretch down. They contain a large amount of poison.
Jellyfish feed on plankton, small crustaceans and fish.
Jellyfish come in different sizes, from a few millimeters to several meters. The largest polar jellyfish lives in the northern seas. Its tentacles are up to 30 meters long and 2 meters in diameter.
Jellyfish about the sea
Poems composes,
But only about this
Nobody will know
She has no hands
To hold a pen
She doesn't have a mouth
To read aloud.
The jellyfish composes for itself,
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 are able to glow in the dark. In the light of this living lantern, small crustaceans swim, right into the tentacles of the insidious jellyfish.
Other jellyfish also glow. The umbrella and tentacles of the pelagia jellyfish burn 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 blazing with red fire.

slide 2

Sea hedgehog flat

The sea urchin (Echinarachnius parma) lives in soft ground where it can move in all directions. This brownish or lilac hedgehog, covered with greenish needles, has a low shell with a rather thin edge, the diameter of which reaches 10 cm. With the help of needles, it digs soil on itself and can disappear from view in 10-15 minutes. These hedgehogs have been found at depths up to 1625 m and in some places form large aggregations. Representatives of this species are found in the northern and northwestern parts of the Atlantic Ocean, then in the southern part of the Chukchi Sea and in the northern regions of the Pacific Ocean along the Asian coast south to Posyet Bay and the coast of Japan, and along the American coast to Puget Sound, including the Aleutian Islands . Interestingly, young hedgehogs Echinarachnius parma select black heavy grains of iron oxides from sand and fill diverticula (outgrowths) of the intestines with them. By doing this, they make their body heavier, since the density of such grains is 2.5 times greater than the density of the hedgehogs themselves. In this way, they resist washing them out of the ground. Adult hedgehogs do not accumulate heavy grains.

slide 3

Strongylocentrus purple

Strongylocentrus purple (Strongylocentrotus purpuratus), according to Irwin, makes a large number of holes in the steel piles of the port facilities of the Pacific coast of California. This medium-sized hedgehog is covered with numerous strong, long, purple-colored needles, which it rotates to drill holes for itself. Obviously, his teeth help him in this work.

slide 4

Hedgehog sea red-green

Red-green sea hedgehog (Sphaerechinus granularis) This species, distributed mainly in the littoral zone, is very beautiful. Its large, up to 13 cm in diameter, shell has a purple color, with lighter zones on the ambulacras and a greenish apical field. On the shell are purple or purple needles with white ends. The hedgehog often climbs into the crevices between the rocks, but he never makes minks. Like many shallow water animals, it often covers itself with pieces of algae, shells, or other objects. It usually crawls slowly among thickets of algae, feeding on them. Sometimes collects detritus with small organisms in it. Its poisonous globiferous pedicellariae are a protective device against the attack of the main enemies - starfish. The hedgehog manages to escape if only one star attacks, but even poisonous pedicellaria cannot save it if several predators attack at the same time.

slide 5

Tripneus

Tripneustes (Tripneustes ventricosus) Fishermen on the island of Martinique catch it on coral reefs that border a large lagoon in the Atlantic Ocean. It is obtained either by divers or from rafts using a bamboo stick split at the end. The collected hedgehogs are opened on the shore, the caviar is taken out of the shell and boiled in a cauldron over low heat until it looks like a thick mass of beeswax color, after which it is again laid in the peeled shell of the hedgehogs. Shells of hedgehogs with boiled caviar are sold by peddlers by the piece. Every year, the Creole population consumes such a large number of hedgehogs that in some places on the island their shells form whole mountains.

slide 6

sea ​​shore hedgehog

Sea hedgehog (Psammechinus miliaris) It can be found along the European coast of the Atlantic Ocean from Norway to Morocco. It is fairly common on oyster banks and in surf spots. He is not afraid of strong waves, since with the help of coarse short needles he makes a depression in the ground, where he hides. The diameter of its shell is not more than 50 mm, its color is greenish, the needles are green with a purple tip. Feeding on all kinds of animal food (hydroids, sessile polychaetes, young oysters, etc.), it, like starfish, harms oyster farms. This hedgehog is so omnivorous that in the aquarium it ate ascidians, dead fish, caviar, raw meat, crayfish, dead crabs, soft parts of mollusks, bryozoans, worms, hydroids, sponges, various algae, including calcareous ones. There are cases when this hedgehog lived in an aquarium for three years. When feeding in captivity, food is placed directly on the animal's shell, then he quickly begins to move it into his mouth with the help of legs and needles.

Slide 7

Sea rock hedgehog

The sea rock urchin (Paracentrotus lividus), distributed from the coast of Great Britain to Africa, including the Mediterranean Sea, is the most famous rock driller. It forms often huge aggregations on sloping rocky surfaces and in seagrass beds. It can be found from the littoral to a depth of 30 m. It is curious that the Mediterranean race of these hedgehogs differs somewhat in behavior from the behavior of the Atlantic race. So, individuals living in the Atlantic Ocean settle in the recesses of the rocks, made by them with the help of needles and teeth. On the contrary, in the Mediterranean Sea they never drill rocks, but settle on slightly inclined surfaces and cover themselves with pieces of shells, sea grass and other objects. The drilling of shelters is obviously associated with the great destructive power of the ocean surf. Sometimes sea urchins are walled up in shelters, as the diameter of the entrance to the hole becomes smaller than the diameter of the urchin's body. Fleeing from the waves, the little hedgehog makes a refuge in the rock and stays there for a long time. His body grows, he expands the depression around him, but the entrance to it remains the same, and after a while the hedgehog becomes a prisoner of his house, eating only what the waves bring him into the mink. These hedgehogs are herbivorous, they eat various algae and sea grass. Their shell reaches a diameter of 7 cm. Its color varies from dark purple to greenish-brown. According to some observations, males and females differ in color: males are darker, females are brighter. Sexual dimorphism is also manifested in the outline of the shell, which is flatter in females. Sexual products are swept into the water in small portions during the summer. For many animals, this hedgehog is dangerous. Its pedacellaria are poisonous. An extract of 30 pedicellaria quickly killed a crab 4-5 cm long. However, other echinoderms, as well as humans, were immune to this poison. Caviar of a rocky sea urchin is eaten. Its main fishery is carried out in the Mediterranean Sea.

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Edible sea hedgehog

Edible sea hedgehog (Echinus esculentus) harvested off the coast of Portugal, in some areas of Great Britain, in the North Sea. It is distributed from the Barents Sea to the coasts of Spain and Portugal, prefers to settle in coastal waters from the littoral to a depth of 40 m, less often up to 100 m, but there is a known case of its being at a depth of 1200 m. The appearance of this hedgehog is very beautiful. It has a large, up to 16 cm in diameter, spherical reddish shell, covered with short, thin, reddish needles with purple tips and a large number of pedicellaria, with the help of which the animal keeps the shell clean and also gets its own food. This hedgehog is omnivorous. His intestines are always densely packed with various algae, especially seaweed, as well as the remains of various small animals: barnacles, hydroid polyps, bryozoans, and even the remains of other sea urchins. This makes it easy to keep in an aquarium. In a calm state, he can sit for a long time at the bottom of the aquarium, stretching up a whole forest of ambulacral legs. With the help of legs, needles and pedicellaria, it delivers food to the mouth. It is curious that when moving, this hedgehog often uses the teeth of an Aristotelian lantern. In this case, the teeth sink into the substrate, close and lift the hedgehog, then it moves forward with the help of needles. Moving on ambulacral legs, he can walk 15 cm in 1 minute.

Slide 9

Heterocentrotus

Heterocentrotus (Heterocentrotus mammillatus) has very thick, coarse needles that help it dig caves in coral polypnyak. He does this mainly with the needles of the oral side, the ends of which are equipped with thin teeth. This mink is so small that the animal in it can hardly turn. Sometimes a growing hedgehog remains walled up in a cave and feeds only on what the sea surf brings to its shelter, so the minks of this hedgehog are literally licked.

Slide 10

Colocentrotus

Colobocentrotus (Colobocentrotus atratus) has adapted well to life in a strong surf zone. Its shell is low, oval, armed with short polygonal needles. Spatulate needles are located along the edge of the oral side. The flat mouth surface of the carapace, together with spatulate marginal needles directed obliquely downwards, and numerous ambulacral legs create such a powerful suction disk that the hedgehog can only be unhooked from the rock with a knife. The flattened aboral surface of the shell, armed with short polygonal needles, perfectly resists the action of waves. This hedgehog feeds on various organisms living next to it, such as calcareous algae. The commensal of this hedgehog can be considered the planaria Ceratoplana colobocentroti, which hides under its shell to stay in the surf. Among its cohabitants are the small crab Proechinoecus dimorphicus and one species of molluscs.

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Sea hedgehog heart-shaped

The sea urchin (Echinocardium cordatum) lives in the temperate latitudes of the Atlantic and Pacific Oceans from the littoral to a depth of 230 m. This hedgehog lives by burrowing into the sandy soil, where it makes moves, strengthening their walls with mucous secretions. It burrows into the ground with the help of lateral needles to a depth of approximately 20 cm. When the hedgehog sits in the ground, it is connected to the surface by a vertical passage cemented with mucus. Through this passage, thanks to the movements of the needles, which cause the water cycle in the mink, fresh water enters it, containing oxygen necessary for breathing. The cystic forelegs of the animal are strongly elongated, protruding outward through a vertical passage (tube). The sticky outgrowths of these legs quite quickly collect the required amount of food from the ground surface and, being pulled back into the mink, transfer food particles to the needles on the upper lip, which direct them into the mouth. At the same time, the hind legs are stretched a few centimeters back into the posterior tube and contribute to better removal of excrement. Hedgehogs in search of food slowly crawl in the ground, pushing off with paddle-like abdominal spines. In this case, the back tube crumbles, and the upper (breathing) tube is made anew. Hedgehogs rarely appear on the surface of the ground, as they risk being carried away by the waves of the tide.

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Hedgehog heart-shaped purple

Purple heart-shaped hedgehog (Spatangus purpureus) makes not very deep moves. He lives more often on a broken shell and deepens only 5 cm from the surface, does not construct a respiratory passage. This large hedgehog, reaching a length of 12 cm, has a purple shell and lighter, sometimes even white, curved spines on the dorsal side. It is distributed in the northern part of the Atlantic Ocean along the European coast to the Azores and the Mediterranean Sea. It occurs up to a depth of 900 m. This hedgehog breeds in the summer months, like most of its fellows, lays eggs in the water, where they pass through the larval stage of Echinopluteus, characterized by a long posterior process.

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Sea stars (Asteroidea)