Presentation on the topic whale shark. Presentation on the topic "sharks". Features of the organization of cartilaginous fish
General characteristics of the Shark Superorder: 1) the skeleton consists of cartilage; 1) the skeleton consists of cartilage; 2) 5 or 6 gill openings; 2) 5 or 6 gill openings; 3) the heart consists of two chambers, one ventricle and one atrium; 3) the heart consists of two chambers, one ventricle and one atrium; 4) sharks have 2 small holes on their heads - squirters; 4) sharks have 2 small holes on their heads - squirters; 5) live in the water column; 5) live in the water column; 6) the head of sharks ends in an elongated snout - rostrum; 6) the head of sharks ends in an elongated snout - rostrum; 7) the large mouth is located on the underside of the head and looks like a transverse slit; 7) the large mouth is located on the underside of the head and looks like a transverse slit; 8) the jaws are armed with several rows of sharp teeth; 8) the jaws are armed with several rows of sharp teeth; 9) sharks do not have a swim bladder; 9) sharks do not have a swim bladder; 10) the skin is covered with scales with jagged spines covered with enamel. 10) the skin is covered with scales with jagged spines covered with enamel.
Hammerhead shark (Sphyma mokarran) The largest hammerhead shark, recognizable by its outstanding size (up to 6.1 m) and very high dorsal fin. The largest hammerhead shark, recognizable by its outstanding size (up to 6.1 m) and very high dorsal fin.
Whale shark (Rhicodon typus) Its size often exceeds 10 m, there is evidence of 18-meter and even 20-meter specimens, although such individuals are extremely rare. Its size often exceeds 10 m, there is evidence of 18-meter and even 20-meter specimens, although such individuals are extremely rare.
Frilled shark (Chlamydoselachus anguineus) The frilled shark is found at a considerable depth (meters), in the bottom layers of water. The frilled shark is found at a considerable depth (meters), in the bottom layers of water.
The presentation was prepared by Pavel Dekhtyarenko, a student of grade 7 “B”. List of websites and books used for the presentation: Dunaeva Yu.A./Sharks and Rays. – St. Petersburg; “A.V.K. - Timoshka", Nikishov A.I. Biology. Animals: textbook. For 7th grade students. general education textbook institutions - M.: VLADOS, 2011.
Description of the presentation by individual slides:
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When fish appeared in the seas Fish appeared about 500 ml. years ago. They were the first vertebrates. The fish did not have jaws or fins, and in appearance the animals resembled modern tadpoles.
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The most ancient sharks They appeared on Earth about 400 million years ago. Sharks were among the very first vertebrates to “acquire” jaws with sharp teeth. And even then, in the prehistoric period, they were just as ferocious and bloodthirsty as in our time
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Shark teeth Sharks have powerful jaws with double rows of sharp teeth. When the outer row of teeth wears out, they are replaced by the inner row of teeth, and new ones begin to grow in the back. During their life, a thousand teeth are replaced.
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Shark skeleton The skeletons of all sharks are made of cartilage, which, for example, is also the material for our ears. Therefore, sharks are strong and very flexible. The lack of a bony skeleton, however, makes them especially vulnerable, which is another reason not to make sweeping generalizations about sharks.
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Senses of sharks Sharks have an excellent sense of smell - they can smell blood at a distance of hundreds of meters. Sharks practically do not feel pain, because their body produces a certain “opium” that dulls pain.
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Adaptation Sharks are amazingly adaptable. For example, if there is not enough oxygen, they can “shut down” part of the brain and use less energy. Sharks can also regulate the salinity of water by developing special means. Shark vision is several times better than that of cats. In dirty water they can see up to 15 meters away.
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Shark scales Sharks do not have regular scales, they have placoid scales or dermal teeth. They resemble teeth much more than regular scales. The enamel crown, which is the tooth-like part, attaches the dermal tooth to the skin. This armed to the teeth skin reduces friction in the water and increases the speed of movement of sharks.
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It’s interesting that... A variety of objects were found in the stomachs of sharks - for example, bottles, jute bags, postal parcels, shells and grenades, spinning rods and even a large African tam-tam. There are known cases of sharks attacking yachts and fishing boats.
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Also... Sharks don't have a swim bladder. They maintain their position in the water because the water washes over their fins. If they stop moving, they will drown. They don't have brakes, so they won't be able to stop quickly.
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Sharks These are the largest fish. Some weigh more than an elephant and are longer than a bus, but not all sharks are so huge. Most sharks are predators. They hunt other living creatures and kill them to satisfy their hunger.
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Young sharks All sharks are fish, but they do not spawn. Some sharks lay eggs covered with durable shells. Others give birth to fully formed babies that developed inside the mother shark's body and fed on her. Newborn baby sharks must feed and protect themselves from the very beginning. Small sharks are eaten by many predators, including sharks.
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Let's look at the largest sharks. The largest sharks in the world today continue to simultaneously amaze and terrify with their size. These underwater inhabitants are extremely interesting creatures. It would be a misconception to consider them exclusively marine predators. Among them there are species that feed only on plankton and krill, and some of the sharks live in freshwater.
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Mako shark is capable of reaching high speeds in a throw - more than 70 kilometers per hour. She jumps out of the water 6 meters, which makes her one of the most agile and dangerous sea predators. The average body size is 3.2 - 3.5 meters. The mako shark poses a danger to humans, but in most cases attacks on people were provoked. The embryos of these sharks attack each other in the womb and find out which of them can survive. They develop tiny but sharp teeth.
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Fox shark reaches more than 6 meters in length. Most of the length of its body is occupied by an elongated caudal fin. When hunting, they use their tail as a whip and with its help they first drive and then stun their prey. The fox shark can jump completely out of the water. Its large size makes it outwardly formidable, but in fact it does not pose a danger to humans, since it is quite shy.
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Sixgill shark 5.4 meters - maximum recorded length. On average, the size of this shark is 3-4 meters. It does not pose a danger to humans, but it has a negative attitude towards touch and tries to move away from divers into the depths. Despite its apparent slowness and clumsiness, during a hunt, the sixgill shark is capable of making swift dashes after an escaping prey.
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The giant hammerhead shark got its name due to its impressive body size. Maximum length – 6.1 meters. The average size of a hammerhead shark is 3.5 meters. It rarely attacks people, but is a potentially dangerous marine predator. This shark is named for its strange hammer-shaped head. The shark's eyes are located on the outer edges of the hammer, with large nostrils slightly receding from them. While swimming, the fish turns its head from side to side, looking for and sniffing out prey.
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Tiger shark The body size of this species reaches an average of 5 meters, but can be more than 7 meters. Like the white shark, this species is the most dangerous to humans. Parts of human bodies are often found in the stomachs of these marine predators. To protect people from attacks, tiger sharks are hunted in some countries.
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Pelagic largemouth shark It is also one of the most poorly studied species. This deep-sea inhabitant was discovered quite recently - in 1976. The maximum size of a caught individual reached 5.70 meters. Scientists have discovered only 60 largemouth sharks.
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White shark It is often called the “killer shark”. It impresses not only with the enormous power of its jaws, but also with its size. Some specimens can reach 6 meters in length, although they are generally smaller. The white shark is an endangered species, with only 3,500 individuals left in the world. White sharks prey on sea lions and other marine mammals. They attack people more often than other sharks. Up to 50 cases are reported annually, 6 of which are fatal.
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Greenland polar shark Belongs to the largest sharks in the world, living in northern waters. Its size can reach 6-7 meters, and its weight can be one and a half tons. Because of its slowness, according to scientists, it uses special tactics during the hunt - it catches seals when they are sleeping peacefully in the water. The polar shark is one of the slowest fish on Earth. Its speed does not exceed 2.7 kilometers per hour, which is due to the low temperature of its habitat.
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Giant (gigantic) shark Males are slightly smaller than females, the size of the latter reaches 9.8 meters. Due to mass extermination, large specimens are now extremely rare. The giant shark feeds on plankton, krill and small fish. It is not dangerous to humans, although it looks menacing when it opens its mouth wide. The giant shark allows divers to get close to it. But you should not touch it because of the sharp scales that can injure the skin.
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Whale shark On average, the body length of a whale shark reaches 12-14 meters. To feed itself, this gigantic sea creature has to consume approximately 200 kilograms of plankton and small fish every day. The largest recorded weight of a whale shark was 36 tons. Lives in warm tropical waters.
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Megalodon If we consider extinct species, then the undisputed winner in the ranking of the largest sharks in the world will be Megalodon. Fossil remains suggest that it reached at least 16 meters in length and could weigh about 50 tons. This super predator fed on cetaceans and large fish. It was distributed everywhere and, due to its size, had no enemies.
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The dwarf lantern shark is the smallest shark. Its length is approximately 20 cm. It is rarely seen and little is known about it, as it is a deep-sea shark. Like all lantern sharks, its belly and fins have luminous areas, which it uses for camouflage at shallow depths and for hunting at greater depths. Of course, she only hunts very small creatures - she is small herself.
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20 interesting facts about sharks 1. The smallest shark (deep-sea small shark) is only 15-17 centimeters long, and the largest shark reaches 20 meters (Whale shark). 2. All sharks are predators with sharp teeth, but there are three types of sharks that feed only on plankton - whale, giant and largemouth. 3. Despite their bloodthirstiness and terrifying appearance, sharks very rarely attack people (more people die from lightning strikes). 4. In some countries, shark is eaten. In China, shark fin soup has been prepared for many centuries, and in some countries Hakarl (rotten shark meat) is considered a delicacy. 5. Shark teeth are as strong as steel.
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6. When a tiger shark closes its mouth, its teeth are hidden in its gums, and when it prepares to attack, its teeth extend like the claws of Wolverine. 7. On average, a shark lives 20-30 years, but there are some species (for example, the spotted spiny shark) whose age can reach 100 years. 8. A white shark can survive brain damage that would kill any other creature. 9. Sharks don't have a swim bladder like other fish to stay afloat, but they do have massive oily livers that do the job. 10 The pregnancy of a giant shark lasts about two years. 11. Sharks do not breathe through their noses, but they smell them very well and can smell one drop of blood. 12. Sharks have both upper and lower eyelids, but they never blink. 13. The hammerhead shark can view space 360 degrees.
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14. The bull shark, unlike other sharks, lives in fresh waters. 15. Only teeth make up the bone tissue of a shark; the rest of the skeleton consists entirely of cartilage. 16. In New Zealand there is a species of shark called the Swell Shark. This shark can bark like a dog. 17. In a young shark, the liver makes up 20% of its total mass, and in an adult it is only 6%. 18. A shark’s stomach consists of two sections. One section works like a regular stomach and digests food, and the other section works as a warehouse, i.e. This is how a shark can store food reserves even for weeks. 19. The scales of any shark have exactly the same shape as its teeth. 20. And the last interesting fact about sharks for today. Some sharks are viviparous, i.e. They don’t rush the game, but a baby shark is born immediately. This makes them different from other fish.
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Encyclopedia “Where? What? When?" – Moscow: “Makhaon”, 2015. “Everything about everything” - Moscow: “Makhaon”, 2007. “New Encyclopedia for Schoolchildren” - Moscow: “Machaon”, 2004. http://top10a.ru/top-10-samye-bolshie-akuly-v-mire.html
The ancestors of modern sharks appeared in the oceans about 350 million years ago. The earth then looked completely different than it does now: the continents and oceans had not yet acquired the shapes we are familiar with. Ancient sharks swam where today they sow wheat and build cities. Therefore, fossil remains of sharks are sometimes discovered thousands of kilometers from the sea. Paleontologists - scientists who study ancient forms - most often find shark teeth. Fossil shark teeth are amazing in their size. The largest - 15 cm long and weighing 340 g - belonged to a monster, in whose mouth a man could fit standing up to his full height, and it reached 13 meters in length! The shark sees the world in black and white and is quite hard of hearing. Everyone knows: sharks are predators. The shark attacks everything that seems possible prey: fish, turtles, seabirds and mammals, its fellow sharks, and once sharks attacked an elephant that had entered the sea off the coast of Kenya. A whole horse was found in the stomach of a captured great white shark. In the stomach of another shark, a tiger shark, are the head and front part of the body of a crocodile, the hind leg of a sheep, three seagulls, two sealed one-kilogram cans of green peas and a tin of cigarettes.
- STUDY
- INTERESTING
- DATA
- ABOUT SHARKS
- READING
- TEXT
- Is the sand shark dangerous?
- What does a sand shark look like?
- Describe it in the words of the text.
- What does the sand shark eat?
- Read sentences with interrogative
- and an exclamation point.
- GLAZED –
- become motionless.
- DRAWING
- ILLUSTRATION
- TO TEXT
- PREDATORY FISH
- ZANDER
- BURBOT
- PERCH
- ACNE
- WHO ARE THEY?
- THANK YOU!
- GOOD LUCK!
Presentation on the topic “A little about sharks” on biology in powerpoint format. This presentation for 7th grade students tells a very interesting story about the life of sharks. The work contains 31 slides and a large number of illustrations. Author of the presentation: Delmukhametova L.I.
Fragments from the presentation
- The first traces of sharks are found in the Devonian period (320-265 million years ago.
- There are currently more than 250 known species of sharks
Shark sizes
- The whale shark reaches a length of 14 m and weighs about 13 tons.
- Dwarf glowing shark - 7.5 cm in length
Cartilaginous fish
Sharks have no real bones, only cartilage. In some shark species, so much calcium is deposited in the cartilage that it becomes almost as hard as bone.
Sharkskin
- The shark's tough skin is covered in rows of placoid scales. Placoid scales are dermal teeth. All teeth are directed back. The skin resembles sandpaper.
- The nurse shark's dermal teeth are large and grow so often that it is difficult to insert a harpoon into the shark.
- The tensile strength of shark skin is 500 kg. per square centimeter
Teeth
- Sharks' teeth are arranged in even rows in their mouths, sometimes with 1000 or more teeth in a row. The most common are triangular teeth.
- Behind each tooth there are several more teeth lying in deep pits.
- A huge number of powerful sharp teeth in the shark's mouth helps them grab and tear their prey.
- Large sharks (tiger) have huge jaws.
- A shark can easily swallow an adult human.
How does a shark swim
- A shark does not have a swim bladder. A shark can only stay afloat by moving non-stop.
- The shark moves not only with the help of its tail: they have another engine - a “jet”. By forcefully pushing water out of the gill slits, they move forward.
Sense organs
- Sharks' ears are located inside the head, hidden behind an entire labyrinth, which gives sharks a sensitive mechanism that allows them to detect and interpret any sounds underwater. And since sound travels much further and faster underwater, sharks are able to detect sounds from a distance of a couple of kilometers.
- For many years, there was a theory that sharks have very poor eyesight. The shark tracks prey using its olfactory organs. About 30 meters from the prey, the shark is guided by sight alone
- Recently, theories have become popular according to which sharks have a highly developed sense of taste. According to them, sharks determine from the first bite how high-calorie the caught prey is, how much energy they will receive after absorbing it, etc.
- Sharks' sense of smell is 1000 times more acute than that of humans.
- The lateral line allows the shark to react to any movement of the water.
- Sharks have special pores on their heads that lead to organs called ampullae of Lorenzini. Ampoules react to changes in pressure and temperature.
How do sharks eat?
All sharks are carnivores. Their stomach can digest everything they manage to swallow. The stomach can become greatly stretched and even turn inside out. Sharks can store food in their stomachs “in reserve” for more than a month.
Breath
When a shark opens its mouth to draw in water, the gill slits close. Water washes over the gill filaments, carbon dioxide is released from the blood, and oxygen is absorbed by it.
Shark Vitality
- A “dead” shark often behaves just like a living one; one fisherman, for example, lost his arm, which was bitten off by a gutted shark.
- There is a known case when a fisherman caught a shark, ripped open its belly, released its intestines and threw it back into the sea. When he again cast the hook with the shark's entrails attached to it, he caught it... the same shark!
Shark fishing
- The salted, smoked meat of many types of sharks is very tasty.
- Liver is rich in vitamin A.
- Glue is made from cartilage and skin.
- Shark meat, which is not eaten by humans, is processed into livestock feed.
- Leather is used to produce various products.
- Shagreen - shark skin. Borazo is the most expensive leather. 1 sq. see this skin costs 1 dollar. When processing this skin, the placoid scales are preserved.
- Fat is used in the manufacture of cosmetics.
- Jaws and teeth are used as souvenirs.
- Pancreatin is obtained from the pancreas.
- THE SHARK FISHING IS CURRENTLY DOWN, ALTHOUGH IT IS NOT COMPLETELY EXHAUSTED. IN THE FUTURE IT MAY RESUME WITH NEW POWER, MAINLY FOR THE SAKE OF SHARK MEAT.
- The great white shark, whale shark and basking shark are listed in the Red List of the International Union for Conservation of Nature (IUCN)
- There has been a shark circus in the Hawaiian Islands since time immemorial. Hawaiian "gladiators" fought sharks.
- On the Hawaiian, Marshall, and Salamon Islands, human sacrifices were made to sharks.
