Class Cephalopods. Variety of cephalopods. Download presentation on cephalopods

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CLASS Cephalopods

The most organized shellfish; Number - about 650 species; Sizes - from 1cm to 5m; Habitats: oceans, seas (in the water column and at the bottom) These mollusks are called cephalopods because their leg has turned into tentacles, which are located on the head around the mouth like a halo. Class of cephalopods (octopus, squid, cuttlefish):

External structure 1. The body is bilaterally symmetrical. 2. Divided by interception into the body and a large head. 3. The leg is modified into a funnel located on the ventral side - a muscular conical tube and long muscular tentacles located around the mouth. 4. Octopuses have eight tentacles, cuttlefish and squid have ten. 5. The inner side of the tentacles is covered with numerous large disc-shaped suckers. 6. The body is dressed on all sides with a mantle. Cephalopods are able to quickly change the color of the body; deep-sea species have organs of luminescence.

Internal structure of an octopus

Digestive system. The mouth opening is surrounded by two thick horny jaws. The tongue is located in a highly developed muscular pharynx. On it is a grater (for grinding food). The ducts of poisonous salivary glands enter the throat. Next come a long esophagus, a muscular sac-like stomach, and a long intestine that ends in an anus.

The duct of a special gland, the ink sac, opens into the hindgut. In case of danger, the mollusk releases the contents of the ink bag into the water and, under the protection of this “smoke screen”, hides from the enemy.

The internal structure of the squid

1. Lens. 2. Vitreous body. 3. Retina Sensory organs In terms of structural complexity and visual acuity, the eyes of cephalopods are not inferior to the eyes of many vertebrates. Among the cephalopods, especially large-eyed ones are found. The diameter of the eye of a giant squid reaches 40 cm. Cephalopods have organs of chemical sense, balance, tactile, light-sensitive and taste cells are scattered in the skin.

Nervous system. In cephalopods, it reaches a high complexity. The nerve ganglions of the central nervous system are very large and form a common peripharyngeal nerve mass - the brain. Two large bodies extend from its posterior section.

What's on the octopus menu? All cephalopods are predators, attacking mainly fish and crustaceans, which they grab with their tentacles and kill with a bite from their jaws and poison from the salivary glands. Some animals of this class eat mollusks, including cephalopods, carrion, and plankton.

Respiratory system. Most cephalopods have one pair of gills, which are located in the mantle cavity. Rhythmic contractions of the mantle serve to change the water in the mantle cavity, providing gas exchange.

Circulatory system. Closed, in many places the arteries, after the release of oxygen to the tissues through the capillaries, pass into the veins. The heart consists of one ventricle and two atria. Large vessels depart from the heart, which are divided into arteries, and those into capillaries. 4. Afferent vessels carry venous blood to the gills. 5 . Before entering the gills, the afferent vessels form muscular extensions - venous hearts, which, by rhythmic contractions, contribute to the flow of blood into the gills.

The spermatozoa of males stick together in packets surrounded by a dense membrane - spermatophores. The eggs are large and rich in yolk. There is no larval stage. Reproduction. Cephalopods are dioecious. Fertilization occurs in the mantle cavity of the female. The copulatory organ is one of the tentacles.

A young mollusk comes out of the egg, its appearance is similar to an adult animal. Reproduction. Female squids and cuttlefish attach eggs to underwater objects, and octopuses guard their clutches and juveniles. They reproduce once in a lifetime, after which they die.

role in our life. Use of cephalopods by humans: 1. Eating. 2. Making a sepia watercolor from an ink bag of cuttlefish.

Cephalopods are distinguished by the most perfect structure and complex behavior among other mollusks.

Slides and text of this presentation

Class Cephalopods

Variety of cephalopods

In the class of cephalopods, the most highly organized mollusks, there are about 650 species ranging in size from 1 cm to 5 m. They live in the seas and oceans, both in the water column and at the bottom. This group of mollusks includes octopus, squid and cuttlefish.
These mollusks are called cephalopods because their leg has turned into tentacles, which are located on the head around the mouth with a corolla.

The external structure of the cephalopod

The body of a cephalopod
bilaterally symmetrical.
It is usually divided by an interception into a trunk and a large head, and the leg is modified into a funnel located on the ventral side - a muscular conical tube and long muscular tentacles located around the mouth.
Octopuses have eight tentacles, cuttlefish and squid have ten. The inner side of the tentacles is covered with numerous large
disc-shaped suckers.
The body is covered with a mantle on all sides.

torso

Having overtaken the prey, the squid grabs it with long trapping tentacles, holds the rest of the tentacles near the mouth and bites off a piece with sharp horny jaws. Then the food is ground in the throat with the help of a special grater - radula. The squid cannot swallow the victim whole and even in pieces because of the narrow esophagus.

The beak of the giant squid reaches a length of 15 cm.

The giant squid architeitis is a genus of oceanic squid. The world's largest mollusk. What are the dimensions of the architects? If with tentacles, then the record is 17.4 m. A squid of this size was thrown ashore in New Zealand in 1887. The one found in 1878 on the coast of Newfoundland turned out to be a little smaller: 16.8 m with tentacles, including 6.1 m - a body with a head and 10.7 m - tentacles.

Places marked on the world map
finds of giant squid.

In most cephalopods, the shell is greatly reduced and is hidden in the body of the animal.
In a cuttlefish, the shell looks like a calcareous plate lying under the integument on the dorsal side of the body. The squid has a small “feather” left from the shell, while the octopus has no shell at all. The disappearance of the shell is associated with the high speed of movement of these animals. Cephalopods have a special internal skeleton formed by cartilage: the brain is protected by a cartilaginous skull, supporting cartilages are at the base of the tentacles and fins.

Suckers on the tentacles of an octopus

Octopus. The octopus has invented a sophisticated method of hunting its prey: it covers it with tentacles and sucks on hundreds of suckers, whole rows of which are located on the tentacles. The suction cups also help it move on slippery surfaces without sliding down. On the tentacle of an octopus, suction cups are clearly visible, located in dense rows.

Slide #10

The best protection from enemies is it an attack or a disguise?

Cephalopods do not give up without a fight: they are well armed. Their tentacles are studded with hundreds of suckers, and many squids also have claws, sharp and curved, like those of cats. There are no teeth, but there is a beak. Horny, hooked, it easily bites through fish skin and crab shells, pierces through even strong shells of bivalve mollusks.
Cephalopods in the process of evolution acquired an even more amazing miracle weapon - an ink bomb. Instead of a piece of living flesh, the squid throws out in front of the opened one to devour it, gnawing a crude fake of its own person. The squid, as it were, splits in two before our eyes and leaves its ethereal double to the enemy, and he quickly disappears.

Slide #11

The imitator octopus disguises itself as a poisonous fish, repeating the contours and color of its body and even the way of movement - swimming parallel to the bottom

Slide #12

Internal structure of a cephalopod

Slide #13

Internal structure of an octopus

Slide #14

Internal structure of an octopus

Slide #15

sense organs

The sense organs are well developed.
According to the complexity of the structure and visual acuity
the eyes of cephalopods are not inferior
eyes of many vertebrates.
Especially found among cephalopods
big-eyed. giant eye diameter
squid reaches 40 cm.
The cephalopods have
organs of chemical sense, balance,
tactile are scattered in the skin,
light-sensitive and taste cells.

Slide #16

Reproduction of cephalopods

Cephalopods are dioecious animals. During reproduction, male cephalopod mollusks take one of their hands out of the mantle cavity, packed in "bags" of sperm and transfer it to the female's spermatheca. The sizes of spermatophores are from 3 mm to 115 cm.

Slide #17

Caring for offspring

Mother octopuses never leave their eggs for a moment. Rinse gently with fresh water. They drive away anyone who encroaches on them. And so - from 1 to 4 months without food.

Slide #18

General signs of cephalopods:

1.no sink,
2. the body is divided into: head, tentacles, funnel;
3. respiratory organs - gills;
4. 3-chambered heart;
5. well developed sense organs;
6.complex nervous system.

Slide #19

Slide #20

The value of cephalopods for humans

Squid is not only canned, but also dried, fried, boiled. Even in ancient Rome, skillfully cooked octopus was a common food. AT recent times"Gastronomic" human interest in cephalopods has increased dramatically, since their meat is a complete protein food that can replace fish. Squids, on the other hand, can be found in thousands of flocks in the sea, they are easy to get with nets. Octopuses are caught one by one - with spears or with the help of "jug traps". In some countries, paint and ink are made from the ink liquid of cephalopods.
In addition, cephalopods are used as laboratory animals.

Medium comprehensive school № 16

Public lesson on the topic:

« »

Prepared by: Biology teacher Kazmukanova B.E.

Date: 11/23/2015

Uralsk-2015

Topic: " Octopus, squid, cuttlefish. Features of their structure. Movement. Food. Behavior. Role in biocenosis and practical value. »

Lesson Objectives:

1. To introduce students to the variety of cephalopods.

2. To reveal the features of the structure and life processes of cephalopods.

3. Show their significance in nature and human life.

Educational:

To study the features of the structure and life of cephalopods.

To reveal the role of cephalopods in nature and practical significance for humans.

Developing:

To develop in students the ability to analyze, compare, justify the structural features of cephalopods in connection with their habitat.

Educational:

To cultivate love for all living things through the disclosure of the role of cephalopods in nature and human life.

Lesson structure

Organizing time 1 minute

Mental attitude 1 min

Updating knowledge 7 min

Learning a new topic 10 min

Pinning a new topic 15 min

Secondary fastening (sheet feedback) 5 minutes

Student message 5 min

Reflection 1 min

Homework 1 min

During the classes

1. Organizational moment (2 min)

Epigraph to the lesson:

My friends! I am very happy!

Enter your friendly class

And for me the reward

Attention of your smart eyes.

I know; every class is a genius

But without labor, talent is not for the future,

Cross the swords of your opinions -

We will write a lesson together.

2. Greeting (psychological attitude)

Guys, in order to tune in to the lesson, let me give a piece of my warmth. I wish that today in the lesson you have good mood. Next, the children say wishes to each other for the lesson.

Guys, please divide into groups. At the very beginning, the students sit in their rows in large groups of desks. Then, with the help of lots, the division into groups takes place.

To do this, I ask you to come to the desk and take the sheets with the indicated drawings, three groups of Squid, Cuttlefish, and Octopus are formed. (Lots in the box)

1. What is the name of the sweet skin of the body in mollusks?

Answer: Mantle

2. Between the body and the mantle is?

Answer: mantle cavity

3. What features appeared in the digestive system of mollusks?

Answer: Oral cavity - pharynx with tongue (covered with sharp denticles - grater ) - esophagus - stomach with gland (liver) - middle and hind intestine - anus.

4. Do mollusks first have a special gland?

Answer: Liver

5. Features of the circulatory system in molluscs?

Answer: The circulatory system is open, they have a two-chambered (in gastropods) and a three-chambered (in bivalves) heart. Most have colorless blood, only cephalopods have blue blood.

6. How is molluscs breathing?

Answer: Mollusks that live on land breathe with lungs, mollusks that live in water breathe with gills under the mantle.

7. Types of gastropods?

Answer: Pea, sharovka, meadow grass, pond snail, coils, grape snail, naked slug

8.Nervous system of molluscs?

Answer: A complex accumulation of nerve nodes forms the brain, nodal type.

9. Types of bivalves?

Answer: Mussels, toothless, oysters, scallops, pearl oysters

10. Main function and importance of bivalves?

Answer: Water filters. An oyster filters 10 liters of water per hour, also food for many fish, delicacies, craft objects (buttons, beads, jewelry, fodder flour), shell rock - porous limestone in construction.

11. What classes are included in the type Mollusks.

Answer: Gastropods, Bivalves and Cephalopods.

3. Learning a new topic

The task of our lesson: to find out not only the structure of cephalopods using the example of three species, but also to talk about what role they play in nature and in human life. Here is the purpose and topic of the lesson: Topic: " Octopus, squid, cuttlefish. Features of their structure. Movement. Food. Behavior. Role in biocenosis and practical significance. »

Student: The legend of the "Kraken" sea monster with tentacles (student's report, ahead of the task on new topic)

In the folklore of the Scandinavian peoples, from time immemorial, the legend of the kraken has been known - a huge monster that lives in the sea and holds the whole earth in its tentacles. In a moment of bad mood, he is engaged in destroying sailors, drawing them into his possessions along with the ship. Legends of a gigantic sea monster have existed among sailors for several centuries. In October 1873, three fishermen - two adults and a twelve-year-old boy - were fishing for herring in the Newfoundland area. Suddenly they noticed a huge object floating by. Deciding that it was a fragment of a ship, the fishermen began to row towards it, and one of them hit it with a hook. The “fragment” came to life, threw out two giant arms above the water - tentacles and wrapped them around the longboat. Then the monster began to sink into the water, dragging the boat with it.

Rybakov was horrified. The boat quickly filled with water. A few more seconds and they would have gone to the bottom. But the twelve-year-old boy - his name was Tom Picot - turned out to be more courageous than grown men. He grabbed an ax and chopped off both tentacles. The boat straightened up. The squid released some kind of dark purple liquid from its body, from which the water around the boat immediately darkened. The boy was ready to continue the fight, but the monster, without resuming the attack, began to sink into the water and disappeared.

Frightened fishermen struggled to drive the boat to the shore. They brought home two stumps of tentacles. These tentacles are one of the most valuable acquisitions of zoological science of that time. From that moment began a real scientific study kraken.

Such a legend has been known to us for a long time, which speaks of the appearance of monsters in the sea with tentacles.

Teacher's story:

And as usual, we move on to systematics. We make taxonomies together with children on cephalopods. And check the slide.

Superkingdom Cellular

Eukaryotic Empire

Kingdom Animals

Subkingdom Multicellular

Type Shellfish

Class Cephalopods

Rod Kalmar

ViewPacific squid

Rod Octopus

Viewcommon octopus

Rod Karatitsa

Viewmedicinal cuttlefish

cephalopods - the most unusual, large, predatory and most perfect of the mollusks. Cephalopods have reached a high degree of development. These animals were named cephalopods because they have tentacles or “arms” on their heads, which are also called “legs”, because molluscs often walk on them along the bottom, like on stilts.

All cephalopods are exclusively marine animals. They live only in the oceans and salty seas.

The sizes of cephalopods are very diverse - from 1 cm to 18 m. The body of cephalopods is bilaterally symmetrical, their shell is underdeveloped and they wear it not outside, but under the skin of the back. The underdevelopment or even disappearance of the shell is associated with the high speed of movement of mollusks.

An interesting way of movement of cephalopods: pumping water through itself, the cephalopod glides in azure waters, like a rocket with the rear end of the body forward in a jet way. The speed in this case can reach 50 km / h.

Nervous system cephalopods are also more perfect than those of other molluscs. The nerve ganglions merged to form a near-pharyngeal nerve mass - the brain, from which two large nerves depart. sense organs cephalopods are very well developed. For example, the eyes are as perfect as the eyes of vertebrates. There are also organs of chemical sense, balance, and tactile, light-sensitive and even taste cells are located in the skin.

breathe cephalopods with gills located in the mantle cavity.

Circulatory system cephalopods are almost closed, and the heart consists of 3 chambers (1 ventricle and two atria).

Cephalopods have many protective adaptations: their tentacles are seated with hundreds of suckers. Four, - six-kilogram squids easily bite through the wire line of spinning.

Cephalopods in the process of evolution have acquired an even more amazing miracle weapon -ink bomb. In a moment of danger, molluscs throw out a jet of inky liquid. The ink spreads in the water in a thick cloud, and under the cover of a "smoke screen" the mollusk safely escapes. Ink is produced by a special organ - the pear-shaped outgrowth of the rectum - the ink sac. Not all contents of the ink sac are ejected at one time. An ordinary octopus can put a "smoke screen" six times in a row, and after half an hour it completely restores all the spent ink. Observations have shown that the ejected ink does not dissolve immediately, not before it hits something.

All cephalopods have cells that are elastic, like rubber, under the skin. They are filled with paint, like watercolor tubes. The scientific name for these cells ischromatophores . Chromatophores contain black, brown, red-brown, orange and yellow pigments. An annoyed octopus can go from ash gray in a second to black and then turn back to gray.

After fertilization the female arranges a nest in a hole or cave and lays several thousand eggs in it, which, with the help of mucus, attaches to the ceiling and walls of the hole in bundles-clusters. And from that moment on, it is already inseparably with the eggs, constantly sorting through them, washing them with fresh water and driving away predators from the nest. "Hatching", depending on the species, can last 12 or more months. All this time, the female does not eat anything, rationally using the supply of nutrients accumulated in the liver. And by the time the octopuses hatch, the female may die altogether.

Now you yourself in groups, using the text of the textbook and additional literature, write down the features of the internal structure of cephalopods in the poster.

Pinning a new topic (10 min)

The first group is Squids, the second group is Cuttlefish and the third group is Octopuses. Further on the slides the tasks are highlighted in groups. 5 minutes for preparation and 3 minutes for presentation.

Peer assessment between groups (cards or stickers)

No. 1 group rates No. 3

No. 2 group evaluates No. 1

No. 3 group evaluates No. 2

Task number 1 group

1. Features of the structure of Squid

2. Movement, nutrition, behavior of squids.

Task number 2 group

1. Features of the structure of Cuttlefish.

2. Movement, nutrition, behavior of cuttlefish.

3. Role in biocenosis and practical significance

Task number 3 group

1. Features of the structure of Octopuses.

2. Movement, nutrition, behavior of octopuses.

3. Role in biocenosis and practical significance

Teacher: Conclusion on this work in groups

5. Communication of students on a new topic (advance task)

Creative task

1. The most unusual mollusk on the whole planet

2. Interesting facts about cephalopods

6.Secondary fastening

Feedback sheet

1. Today we studied in the lesson ...

2.We did well...

3.We want to know more about?

4. Most of all I liked ...

7.Reflection (Signal cards or stickers in the lesson)

Lesson grades, student assessment.

8. Homework

1. Creative task "Drawing-mollusk through my eyes"

2. Compilation of a crossword puzzle, a rebus on the topic "Mollusks".

slide 2

shellfish

Types of shellfish

slide 3

Variety of cephalopods

slide 4

These mollusks are called cephalopods because their leg has turned into tentacles, which are located on the head around the mouth with a corolla.

slide 5

The external structure of the cephalopod

The body of cephalopods is bilaterally symmetrical.

It is usually divided by an interception into a trunk and a large head, and the leg is modified into a funnel located on the ventral side - a muscular conical tube and long muscular tentacles located around the mouth.

Octopuses have eight tentacles, cuttlefish and squid have ten. The inner side of the tentacles is covered with numerous large disc-shaped suckers.

The body is covered with a mantle on all sides.

slide 6

Movement of cephalopods

Slide 7

The beak of the giant squid reaches a length of 15 cm.

Slide 8

Slide 9

In most cephalopods, the shell is greatly reduced and is hidden in the body of the animal.

In a cuttlefish, the shell looks like a calcareous plate lying under the integument on the dorsal side of the body. The squid has a small “feather” left from the shell, while the octopus has no shell at all. The disappearance of the shell is associated with the high speed of movement of these animals. Cephalopods have a special internal skeleton formed by cartilage: the brain is protected by a cartilaginous skull, supporting cartilages are at the base of the tentacles and fins.

Slide 10

Suckers on the tentacles of an octopus

slide 11

Is the best defense against enemies an offense or a disguise?

Cephalopods in the process of evolution acquired an even more amazing miracle weapon - an ink bomb. Instead of a piece of living flesh, the squid throws out in front of the opened one to devour it, gnawing a crude fake of its own person. The squid, as it were, splits in two before our eyes and leaves its ethereal double to the enemy, and he quickly disappears.

slide 12

The imitator octopus disguises itself as a poisonous fish, repeating the contours and color of its body and even the way of movement - swimming parallel to the bottom

slide 13

Internal structure of a cephalopod

Slide 14

Internal structure of an octopus

slide 15

Internal structure of an octopus

slide 16

sense organs

The sense organs are well developed.

According to the complexity of the structure and visual acuity, the eyes of cephalopods are not inferior to the eyes of many vertebrates.

Among the cephalopods, especially large-eyed ones are found. The giant squid eye diameter reaches 40 cm.

Cephalopods have organs:

chemical feeling
equilibrium
tactile are scattered in the skin
photosensitive
taste cells.

Slide 17

Reproduction of cephalopods

Slide 18

Caring for offspring

Mother octopuses never leave their eggs for a moment. Rinse gently with fresh water. They drive away anyone who encroaches on them. And so - from 1 to 4 months without food.

Slide 19

General signs of cephalopods:

lack of sink
body divided into: head, tentacles, funnel
respiratory organs - gills
3 chambered heart
well developed sense organs
complex nervous system

Slide 20

The value of cephalopods

slide 21

The value of cephalopods for humans

Squid is not only canned, but also dried, fried, boiled. Even in ancient Rome, skillfully cooked octopus was a common food. Recently, the “gastronomic” interest of a person in cephalopods has increased dramatically, since their meat is a complete protein food that can replace fish. Squids, on the other hand, can be found in thousands of flocks in the sea, they are easy to get with nets. Octopuses are caught one by one - with spears or with the help of "jug traps". In some countries, paint and ink are made from the ink liquid of cephalopods.

In addition, cephalopods are used as laboratory animals.

slide 22

The value of cephalopods in nature

regulate the abundance of fish and crustaceans
are the food of marine animals, especially cetaceans.

Cephalopods are connected by invisible but strong threads of biological relationships with all the inhabitants of the ocean. They eat a lot of fish and crabs and themselves give food to millions of predators that devour them: here are fish - sharks, moray eels, tuna, mackerel, cod; here and birds - albatrosses, skuas, penguins and sea animals - whales, dolphins, seals.

slide 23

Origin of cephalopods

For four hundred million years ammonites and nautiluses floated serenely on the waves. Then they suddenly died out. It happened eighty million years ago, at the end of the Mesozoic era. Science has not established with accuracy when and how belemnites, the closest relatives of squid and cuttlefish, descended from nautiluses. Two hundred million years ago they already plied the seas

slide 24

The squid originated from the belemnites. The kingdom of dinosaurs had not yet reached its greatness, and squids already lived in the sea. Octopuses appeared later - one hundred million years ago, at the end of the Cretaceous period. Well, cuttlefish are very young (in the evolutionary sense) creatures. They began their development at the same time as horses and elephants - just some fifty million years ago.

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cephalopods

slide number 1

Description of the slide:

Presentation on the topic "Cephalopods" by Filyutkina Lisa 7 "a"

slide number 2

Description of the slide:

Unique cephalopods Class Cephalopods are the most unusual, largest and most highly organized of the mollusks. A number of unique features - great activity, method and speed of movement, an unusually highly developed nervous system, the rudiments of "intelligence", a set of defense and attack tools - puts cephalopods above all other groups of invertebrates and allows them to compete with vertebrate animals.

slide number 3

Description of the slide:

Movement of the cephalopod In squids, cuttlefish, and octopuses, the mantle cavity functions as a jet engine. Through the mantle gap, water is drawn into the mantle cavity, and then, when it contracts, it is forced out through the funnel, the body of the mollusk moves in the opposite direction.

slide number 4

Description of the slide:

Exclusively marine Cephalopods are exclusively marine animals. They play very important role in the life of the ocean. As predators, they eat great amount crustaceans, fish and other organisms and, in turn, serve as food for many marine vertebrates - fish, birds, pinnipeds and whales. The main enemy of cephalopods is a giant toothed whale - a sperm whale.

slide number 5

Description of the slide:

External structure The body of cephalopods is bilaterally symmetrical. It is usually divided by an interception into a body and a large head, and the leg is modified into a funnel located on the ventral side - a muscular conical tube and long muscular tentacles located around the mouth. Octopuses have eight tentacles, cuttlefish and squid have ten. The inner side of the tentacles is seated with numerous large disc-shaped suckers. The body is covered with a mantle on all sides.

slide number 6

Description of the slide:

slide number 7

Description of the slide:

Is the best defense against enemies an offense or a disguise? . Cephalopods do not give up without a fight: they are well armed. Their tentacles are studded with hundreds of suckers, and many squids also have claws, sharp and curved, like those of cats. There are no teeth, but there is a beak. Horny, hooked, it easily bites through fish skin and crab shells, pierces through even strong shells of bivalve mollusks. A cuttlefish can crush with its beak the shell of a large crayfish or the skull of a fish twice as large as itself. Cephalopods in the process of evolution acquired an even more amazing miracle weapon - an ink bomb. The squid, as it were, splits in two before our eyes and leaves its ethereal double to the enemy, and he quickly disappears.

slide number 8

Description of the slide:

Circulatory system A highly developed circulatory system enables cephalopods to reach gigantic sizes. Only in the presence of a system of capillaries is the existence of very large animals possible, since only in this case is a full supply of oxygen and nutrients to the massive organs of giants ensured. The blood of cephalopods has a blue color due to the presence in it of the respiratory pigment hemocyanin, which contains copper. Hemocyanin is produced in special gill glands. The organs of excretion are the renal sacs, the appendages of the gill hearts, and the gills themselves. The main metabolic product of cephalopods, ammonia (more precisely, ammonium ions), is not completely released in many squids, but partially accumulates in the body of mollusks, providing them with neutral buoyancy.

slide number 9

Description of the slide:

slide number 10

Description of the slide:

Digestive System Eaten pieces of food then enter the muscular stomach, which receives the digestive juices produced by the liver and pancreas. The activity of the enzymes of these glands is very high, and in 4 hours the food is digested. Absorption occurs in the caecum of the stomach - the caecum, as well as in the liver. Undigested food remains enter the intestine and are thrown out. The liver is a large brownish oval organ usually located in front of the stomach. It performs several functions - it produces digestive enzymes, absorption of amino acids occurs in it, and it is also a storehouse of reserve nutrients. On the ventral side of the visceral mass lies an ink sac with a duct that flows into the intestine. An ink sac is present in most cephalopods.