What kinds of sea cucumbers are there on the earth?

The magical seabed waves are gentle, and algae flourish under rocks and on the fine honey sand bottom covered with leafy algae. There is an echinoderm, that is, sea cucumber. Sea cucumber is one of echinoderms with the greatest economic value, and there are about 900 species in the world, ranging from shallow sea to more than 8000 meters deep sea. There are about 100 species in China's sea area, ranging from Bohai Bay and Liaodong Peninsula in the north to Nansha Islands in the south, especially Xisha Islands, with more than 20 species. There are some world-famous species in China, such as sea cucumber with black body and black chest; White ginseng, a kind of snake with rough meat, is often a submerged fish in cloaca; Radiant anal ginseng, short and blunt body, smooth back; Japanese ginseng (southern waters) is a large, thick and tender sea cucumber with a length of 1 m and a width of1cm. Most sea cucumbers are green or slightly green and look like cucumbers. Their English translation is called sea cucumber. But some are worms, some are like buckets, and some are like carrots.

Sea cucumbers like dark living environment and often hide under coral reefs. They usually inhabit the sediments in the intertidal zone and the lower part of the subtidal zone, and move slowly by the expansion and contraction of the tube feet and muscles, feeding on organic debris, copepods, radiolarians and other microorganisms in the sediments.

Sea cucumber is muscular and can stretch and curl freely. Sea cucumber moves slowly, and it is difficult to escape the attack of carnivores who can dehydrate and swim. Sea cucumbers make their homes on the sand at the bottom of the sea, and you can find their hiding places along the tracks of sea cucumbers. When it was removed, it was not easy to find a rock. When you try to catch it, its body suddenly contracts, which is the basic action of its defense. This action is quite effective against natural enemies.

The body color of sea cucumber is in harmony with the color of the surrounding sediments. This can play a certain role in dealing with natural enemies, and can also guard against sudden attacks by human beings. However, sea cucumber does not rely entirely on the protective color of its own body, but also relies on strength to forcibly push away the sediment to cover its own body as a cover. Sediments are also food for sea cucumbers. Of course, here refers to the fine nutritious sand containing organic matter and bacteria. The sea cucumber swallows these fine sands, passes through the long digestive tract, absorbs nutrients and discharges sediment.

Although sea cucumber belongs to the same family as starfish, it is slightly more delicate than starfish. It can't stand the high temperature above 20℃, but it also has a clever way to deal with it-sleeping in summer. In the relatively long days from summer heat to cold dew every year, when the water temperature exceeds 20℃, the sea cucumber quietly moves deeper into the sea, and many individuals gather together like partners in trouble, lurking under the seabed rocks, with their backs up, shrinking, unable to eat or move, and entering the summer sleep state. This can reduce metabolic rate, conserve body energy and tide over difficulties. When the water temperature drops below 20℃, they wake up from a deep sleep and regain their usual vitality.

The sea, like a starfish, has a strong regenerative ability. Even if its body is cut into two or three sections and put back into the sea, each section will produce a complete sea cucumber. Sea cucumber has another trick that starfish don't have. When it encounters enemy injury, strong stimulation or seawater pollution, it will forcibly expel silt-filled internal organs from the anus or mouth. Throw it at and confuse the enemy, and take the opportunity to escape. If you don't need to use it twice in the future, you will slowly grow new internal organs. This phenomenon is called sewage discharge.

Sea cucumber was named by ancient China people. "Its sexual warming; Enough enemy participation ",hence the name. Sea cucumber is an echinoderm, also known as sea cucumber, which grows on rocks or seaweed at the bottom of the ocean. There are more than 800 kinds of sea cucumbers, and only more than 20 kinds are edible. The varieties of sea cucumbers vary from place to place. China's Xisha Islands and Hainan Island are rich in Plum Blossom Ginseng and Wuyuan Ginseng. Fujian and Zhejiang produce soap ginseng and light ginseng; The northern sea cucumber is only Stichopus japonicus, which is a relatively precious edible sea cucumber variety.

Observing the shape of sea cucumber from the aquarium, its shape is quite ugly. Its slender and round body is covered with meat and fat, and its surface is covered with things like meat spines. No wonder people call it "sea cucumber" vividly. On the other hand, sea cucumber is ugly, but its survival history is surprising. It appeared earlier than primitive fish and began to exist in Precambrian more than 600 million years ago. After systematic study by paleontologists, the bone fragment fossils of sea cucumber have become an important basis for stratigraphic paleontologists to divide strata and study paleogeology, and even become the standard fossils of Jurassic. More than ten years ago, paleontologists in China discovered the skeleton fragments of sea cucumber in the Permian strata in Huaying Mountain, Sichuan and Changxing, Zhejiang (more than 200 million years ago).

Sea cucumbers live in the depths of the sea and can't swim. They just crawl on the seabed by stretching their legs and muscles. The crawling speed is quite slow, 1 hour can't walk 3 meters. It was born with no eyes and no sharp weapon to scare the enemy. In this way, for hundreds of millions of years, in the ocean world where the law of the jungle prevails, how did they survive so far?

An unusually calm period

As we all know, some animals on land have the habit of hibernating. In the cold winter, the water-cooled grass withered and it was difficult to feed, so we had to hide in the nest and rely on the nutrients in the body to survive. Sea cucumbers, on the other hand, choose to sleep in summer when food is abundant. Take Stichopus japonicus as an example. When the water temperature reaches 20℃, it quietly moves to the dark of the deep-sea reef, hiding at the bottom of the stone, with its back facing down. Sleep for three or four months. During this period, you can't eat or move, and your whole body shrinks and hardens until after autumn, when you wake up and resume your activities.

Strange, why do sea cucumbers hibernate in summer?

Oceanographers explained that on weekdays, sea cucumbers feed on small creatures, which are sensitive to the temperature of seawater. When the sea surface is heated, they will go upstream, and when the sea surface is cold, they will dive back to the bottom of the sea. After summer, when the sea surface gets warmer, the small creatures living in the sea will go to the upper waters to breed once a year, but the sea cucumbers living at the bottom of the sea can't follow them and are forced to stop eating. Have to hide under the stone to rest and maintain.

Special and wonderful protection technology

Facing the dangerous underwater environment and all kinds of vicious and cunning enemies, sea cucumber protects itself in a special way. Wind and waves will involve poorly attached sea cucumbers in dangerous situations. But sea cucumbers can predict the weather. When the storm came, it hid in a crack in the stone. When fishermen found that there were no sea cucumbers on the seabed, they knew that a storm was coming and quickly closed their nets and returned.

When insidious and cunning sailboats and greedy and ferocious sharks sneak up on us, the alert sea cucumber quickly sprays long sticky intestines and branch-like scuba into the body cavity, so that the strong enemy can have a full meal, but it escapes without a trace with the recoil of discharging dirt. Of course, an empty sea cucumber without an inner cavity will not die, and new internal organs will be born in about 50 days.

Sea cucumber not only has the unique skill of decontamination and confusing the enemy, but also has the function of "being in two places at once" like a starfish. Cut the sea cucumber into several sections and put it into the sea. After 3 ~ 8 months, each section will grow into a complete live ginseng. Some sea cucumbers also have the ability to cut themselves. When the sea cucumber feels that the external environment is not suitable, it can cut itself into several sections, and each section will grow into a new individual in the future. When fishermen catch sea cucumber, if they don't add salt and alum in time, it will dissolve into a pool of water.

An interesting and strange phenomenon

Sea cucumber and light fish live in harmony. This kind of light fish, also called diving fish, is small and smooth, and often drills into the body cavity of sea cucumber to find food or avoid enemies. The movement of the light fish in and out of ginseng is fast and funny: first, it explores the anus of sea cucumber with its small head, then curls it into the tail, then straightens its body, and then wriggles backwards until it completely drills into the parasite. It is found that there are more than seven light fish living in a sea cucumber. Light fish regard ginseng as a comfortable apartment during the day and come out to find some small crustaceans and other animals to satisfy their hunger at night. Unfortunately, when sea cucumber became the host, it not only didn't get any benefits, but also damaged its internal organs. However, we live in harmony with each other and never part. All sea cucumbers near the coast have almost no light fish lurking and parasitic, while sea cucumbers living in the deep sea generally have one or more light fish lurking in their bodies.

A few years ago, people were surprised to find that a small pure iron ball with a diameter of only 0.002 mm was hidden under the skin of sea cucumber. So far, people can't explain what benefits this small iron ball has for sea cucumbers.

References:

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Interviewee: Really collapsed-Senior Manager Level 6 3-22 20:44

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Exaggerated, in our Dalian, only two of 10 people may not have eaten sea cucumber, and the reason why these two people don't eat sea cucumber is because they look "really sorry for the audience". Yes, sea cucumber has always been the most delicious dish on our table, and it is also a necessary dish for guests and friends. Even some qualified "people who eat ginseng" have to take it every day because it has the function of "diet therapy" to enhance immunity, strengthen yang and nourish yin. And these people are developing rapidly in Dalian at present. Eating is eating, but we can keep the sea. How many people know what kind of sea cucumber we eat? What kind of marine environment does sea cucumber grow in? What are the unknown living habits?

To this end, we specially interviewed Professor Chang Yaqing from Dalian Fisheries College. Maybe after reading the following article, when you eat sea cucumber again, you will say to it, "You look like a cucumber, so interesting!" Sea cucumber, an echinoderm, existed on the earth a long time ago. Paleontologists in China discovered the bone fragments of sea cucumber (the remains of embryonic bones in the inner dermis) in the Permian strata of Huaying Mountain in Sichuan and Changxing in Zhejiang (more than 200 million years ago). This ancient invertebrate gradually spread all over the ocean during the changes of the Milky Way. Now it has reached 900 species, ranging from shallow water to more than 8000 meters deep sea. No wonder fishermen by the sea often say, "Where there is sea water, there will be sea cucumbers."

Stichopus Dalian

China is rich in sea cucumber resources, with about 140 species and about 20 edible species, of which 10 species has high economic value. Produced in Bohai Bay and Liaodong Peninsula in the north and Nansha Islands in the south. The South China Sea is rich in black and black milk ginseng, which looks like plum ginseng in pineapple and white ginseng in snake order. It has snake-shaped stripes on its back and radial anal ginseng, with short and blunt body and smooth back. Stichopus japonicus (also known as Apostichopus japonicus) is abundant in the northern coastal areas, mainly distributed in the coastal areas of Liaoning, Shandong and Hebei. That is to say, what we Dalian people usually eat should be called sea cucumber. As early as the late Qing Dynasty, Zhao Xuemin recorded the sea cucumber in Compendium of Materia Medica: "The sea cucumber produced in Liaodong is black and brown, and its meat is waxy and prickly, so it is called Liaoshen or Stichopus japonicus. Its quality is the best, its medicine temperature is non-toxic, and it has the effects of tonifying kidney, strengthening yang, promoting blood circulation and treating diarrhea and ulcer. "

Stichopus japonicus is generally about 20 cm long and 4 cm in diameter. The body is cylindrical, with 4 6 rows of verrucous feet (meat spines) of different sizes and irregular arrangement, which may be the origin of the name of Stichopus japonicus. Stichopus japonicus usually lives in a harbor with no fresh water injection, lush algae and stable waves. The bottom material is rocky or hard, and the water depth is generally 3 5 cm, and a few can reach 50 meters. Most young individuals live in the intertidal zone. Generally, small individuals live in shallow water, while large individuals live in deep water. Every summer when the water temperature is high, they move to deep water.

Stichopus japonicus has strong vitality and can cope with it calmly at -2℃ and 30℃. The lower the temperature, the slower the growth of Stichopus japonicus, but the quality of Stichopus japonicus is enhanced (the quality enhancement is manifested in the thickness of body wall, the length of thorns and the number of thorns). This is also the reason why the nutritional value of sea cucumber is getting higher and higher and more valuable as the coast goes north. Therefore, it is not difficult to understand why Stichopus japonicus in the northern islands of the Yellow Sea, such as Zhangzidao and Island, are so popular. There have been rumors that people on the island have seen five rows of sea cucumbers. If it is true, it fully explains the physiological characteristics of Stichopus japonicus.

In fact, five rows of spiny fish are not uncommon on the far east coast of Russia. Professor Chang said that the quality of stichopus japonicus in the northern coast of Russia and Japan is much better than that in Dalian. It is not unusual to see six rows of sea cucumbers on the far east coast of Russia. Therefore, Professor Chang tried and successfully carried out the cross breeding of China Stichopus japonicus in Russian coastal areas, hoping to further improve the quality of Stichopus japonicus through "transnational marriage" and maximize its economic value.

Stichopus japonicus loves summer sleep.

Stichopus japonicus not only looks strange, but also has different hobbies. Contrary to snakes, bats, frogs, hedgehogs, bears and other animals with hibernation habits, Stichopus japonicus likes to sleep in summer. After spawning, when the water temperature rises above 20℃, Stichopus japonicus quietly moves to the dark or hidden place on the reef in the deep sea, hiding under the rock with stable water flow, shrinking its body, thinning its digestive tract, and even stopping eating, and sleeping for three or four months. During this period, they can't eat or move, and their whole bodies shrink and harden. They didn't wake up until the autumnal equinox, when the water temperature dropped.

Professor Chang said that Stichopus japonicus in different sea areas of Dalian entered the summer sleep at different times. For example, Stichopus japonicus in Jinzhou went into hiding at the end of June, and Stichopus japonicus in the northern part of the Yellow Sea began to sleep in the middle and late July.

Professor Chang said that there are two explanations for the strange summer sleep phenomenon of Stichopus japonicus. Some people think that it is caused by "biological rhythm": Stichopus japonicus is a temperate species, which has formed an inadaptability to high temperature in the long-term evolution process, so when the temperature rises, Stichopus japonicus relies on rest to maintain its physical strength. Another view is that summer sleep is restricted by the completion of sexual activities. After laying eggs, Stichopus japonicus consumes most of its energy and needs a long rest, so it chooses summer sleep, which is somewhat similar to what people often say about "confinement" and "maternity leave".

Ecological Restoration of Sea Cucumber

Summer dormancy may be a unique physiological feature of Stichopus japonicus, but its ecological restoration is possessed by all sea cucumber species.

How does sea cucumber repair the ecology? In fact, it is very simple, that is, it is done by "eating". Sea cucumbers that feed on sediments rely on tentacles to clean, scrape or grab loose sediments and precipitated particles on the substrate surface, mainly including organic debris, decaying debris of animals and plants, feces of other animals and even their own feces. Sea cucumbers swallow a lot of sediment, and each sea cucumber can swallow 68g of sediment per hour, which is 5070kg a year.

In this way, unconsciously, sea cucumber cleaned up the underwater world and played a role in restoring ecology. Therefore, sea cucumbers also have the reputation of "sea porters" and "sea cleaners". Unexpectedly, the ugly sea cucumber can not only satisfy the pursuit of human health, but also have such great significance in ecological research. Maybe we should give them a "lifetime contribution award".

Super self-protection consciousness

The self-protection of sea cucumber is mainly realized by vomiting intestine, self-cutting and discoloration.

When the sea cucumber is in unfavorable environmental conditions, such as sea water pollution, high water temperature or some strong stimulation, the protection technology adopted is to quickly eject the intestine and dendritic scuba into the body cavity. Empty sea cucumbers without internal organs will not die, and new internal organs will be born in about 50 days; A body that is cut into several segments will also grow new individuals in each segment. This ability is actually the nature of echinoderms, and it has a strong regenerative ability after losing some organs or parts of the body.

However, Professor Chang stressed that the fact that sea cucumber has the ability to regenerate does not mean that it can be regenerated anytime and anywhere. If someone is whimsical, buy a sea cucumber and cut it into several pieces, expecting to have a few sea cucumbers, it is tantamount to waiting for him, which can only make people laugh.

The body color of sea cucumber changes with the change of environment. Generally, the body color of sea cucumber is similar to the surrounding environment. Sea cucumbers living near reefs will turn pale blue, sea cucumbers living near brown algae will turn brown, and sea cucumbers growing around green algae will turn green. Professor Chang's graduate student once found a pure white sea cucumber in Fujiazhuang sea area of Dalian, but Professor Chang said it was the result of genetic variation, not the change of the color of the celestial sphere.

Although sea cucumber has a strong sense of self-protection and amazing "self-protection" ability, it will inevitably be infringed by nature and human beings. In fact, there are very few animals that eat sea cucumbers in the underwater world, and their biggest enemy is probably more and more "cannibals". Professor Chang finally said: "Reasonable fishing, scientific layout and scientific breeding may be the only way to solve the problem."

Answer: MLF Q&Q- magic apprentice level 1 3-22 2 1: 12

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About 10000 species. A few years ago, people were surprised to find that a small pure iron ball was stored under the skin of sea cucumber, and the diameter of this small iron ball was only 0.002 mm. So far, people can't explain what benefits this small iron ball has for sea cucumber.

The magical seabed waves are gentle, and algae flourish under rocks and on the fine honey sand bottom covered with leafy algae. There is an echinoderm, that is, sea cucumber. Sea cucumber is one of echinoderms with the greatest economic value, and there are about 900 species in the world, ranging from shallow sea to more than 8000 meters deep sea. There are about 100 species in China's sea areas, ranging from Bohai Bay and Liaodong Peninsula in the north to Nansha Islands in the south, especially Xisha Islands, with more than 20 species. There are some world-famous species in China, such as sea cucumber with black body and black chest; White ginseng, a kind of snake with rough meat, is often a submerged fish in cloaca; Radiant anal ginseng, short and blunt body, smooth back; Japanese ginseng (southern waters) is a large, thick and tender sea cucumber with a length of 1 m and a width of1cm. Most sea cucumbers are green or slightly green and look like cucumbers. Their English translation is called sea cucumber. But some are worms, some are like buckets, and some are like carrots.

Sea cucumbers like dark living environment and often hide under coral reefs. Usually, it lives in the sediments in the intertidal zone and the lower part of the subtidal zone. It uses the expansion and contraction of the tube feet and muscles to move slowly, and feeds on organic debris, copepods, radiolarians and other microorganisms in the sediments.

Sea cucumber is muscular and can stretch and curl freely. Sea cucumber moves slowly, and it is difficult to escape the attack of carnivores who can dehydrate and swim. Sea cucumbers make their homes on the sand at the bottom of the sea, and you can find their hiding places along the tracks of sea cucumbers. When it was removed, it was not easy to find a rock. When you try to catch it, its body suddenly contracts, which is the basic action of its defense. This action is quite effective against natural enemies.

The body color of sea cucumber is in harmony with the color of the surrounding sediments. This can play a certain role in dealing with natural enemies, and can also guard against sudden attacks by human beings. However, sea cucumber does not rely entirely on the protective color of its own body, but also relies on strength to forcibly push away the sediment to cover its own body as a cover. Sediments are also food for sea cucumbers. Of course, here refers to the fine nutritious sand containing organic matter and bacteria. The sea cucumber swallows these fine sands, passes through the long digestive tract, absorbs nutrients and discharges sediment.

Although sea cucumber belongs to the same family as starfish, it is slightly more delicate than starfish. It can't stand the high temperature above 20℃, but it also has a clever way to deal with it-sleeping in summer. In the relatively long days from summer heat to cold dew every year, when the water temperature exceeds 20℃, the sea cucumber quietly moves deeper into the sea, and many individuals gather together like partners in trouble, lurking under the seabed rocks, with their backs up, shrinking, unable to eat or move, and entering the summer sleep state. This can reduce metabolic rate, conserve body energy and tide over difficulties. When the water temperature drops below 20℃, they wake up from a deep sleep and regain their usual vitality.

The sea, like a starfish, has a strong regenerative ability. Even if its body is cut into two or three sections and put back into the sea, each section will produce a complete sea cucumber. Sea cucumber has another trick that starfish don't have. When it encounters enemy injury, strong stimulation or seawater pollution, it will forcibly expel silt-filled internal organs from the anus or mouth. Throw it at and confuse the enemy, and take the opportunity to escape. If you don't need to use it twice in the future, you will slowly grow new internal organs. This phenomenon is called sewage discharge.

Sea cucumber was named by ancient China people. "Its sexual warming; Enough enemy participation ",hence the name. Sea cucumber is an echinoderm, also known as sea cucumber, which grows on rocks or seaweed at the bottom of the ocean. There are more than 800 kinds of sea cucumbers, and only more than 20 kinds are edible. The varieties of sea cucumbers vary from place to place. China's Xisha Islands and Hainan Island are rich in Plum Blossom Ginseng and Wuyuan Ginseng. Fujian and Zhejiang produce soap ginseng and light ginseng; The northern sea cucumber is only Stichopus japonicus, which is a relatively precious edible sea cucumber variety.

Observing the shape of sea cucumber from the aquarium, its shape is quite ugly. Its slender and round body is covered with meat and fat, and its surface is covered with things like meat spines. No wonder people call it "sea cucumber" vividly. On the other hand, sea cucumber is ugly, but its survival history is surprising. It appeared earlier than primitive fish and began to exist in Precambrian more than 600 million years ago. After systematic study by paleontologists, the bone fragment fossils of sea cucumber have become an important basis for stratigraphic paleontologists to divide strata and study paleogeology, and even become the standard fossils of Jurassic. More than ten years ago, paleontologists in China discovered the skeleton fragments of sea cucumber in the Permian strata in Huaying Mountain, Sichuan and Changxing, Zhejiang (more than 200 million years ago).

Sea cucumbers live in the depths of the sea and can't swim. They just crawl on the seabed by stretching their legs and muscles. The crawling speed is quite slow, 1 hour can't walk 3 meters. It was born with no eyes and no sharp weapon to scare the enemy. In this way, for hundreds of millions of years, in the ocean world where the law of the jungle prevails, how did they survive so far?

An unusually calm period

As we all know, some animals on land have the habit of hibernating. In the cold winter, the water-cooled grass withered and it was difficult to feed, so we had to hide in the nest and rely on the nutrients in the body to survive. Sea cucumbers, on the other hand, choose to sleep in summer when food is abundant. Take Stichopus japonicus as an example. When the water temperature reaches 20℃, it quietly moves to the dark of the deep-sea reef, hiding at the bottom of the stone, with its back facing down. Sleep for three or four months. During this period, you can't eat or move, and your whole body shrinks and hardens until after autumn, when you wake up and resume your activities.

Strange, why do sea cucumbers hibernate in summer?

Oceanographers explained that on weekdays, sea cucumbers feed on small creatures, which are sensitive to the temperature of seawater. When the sea surface is heated, they will go upstream, and when the sea surface is cold, they will dive back to the bottom of the sea. After summer, when the sea surface gets warmer, the small creatures living in the sea will go to the upper waters to breed once a year, but the sea cucumbers living at the bottom of the sea can't follow them and are forced to stop eating. Have to hide under the stone to rest and maintain.

Special and wonderful protection technology

Facing the dangerous underwater environment and all kinds of vicious and cunning enemies, sea cucumber protects itself in a special way. Wind and waves will involve poorly attached sea cucumbers in dangerous situations. But sea cucumbers can predict the weather. When the storm came, it hid in a crack in the stone. When fishermen found that there were no sea cucumbers on the seabed, they knew that a storm was coming and quickly closed their nets and returned.

When insidious and cunning sailboats and greedy and ferocious sharks sneak up on us, the alert sea cucumber quickly sprays long sticky intestines and branch-like scuba into the body cavity, so that the strong enemy can have a full meal, but it escapes without a trace with the recoil of discharging dirt. Of course, an empty sea cucumber without an inner cavity will not die, and new internal organs will be born in about 50 days.

Sea cucumber not only has the unique skill of decontamination and confusing the enemy, but also has the function of "being in two places at once" like a starfish. Cut the sea cucumber into several sections and put it into the sea. After 3 ~ 8 months, each section will grow into a complete live ginseng. Some sea cucumbers also have the ability to cut themselves. When the sea cucumber feels that the external environment is not suitable, it can cut itself into several sections, and each section will grow into a new individual in the future. When fishermen catch sea cucumber, if they don't add salt and alum in time, it will dissolve into a pool of water.

An interesting and strange phenomenon

Sea cucumber and light fish live in harmony. This kind of light fish, also called diving fish, is small and smooth, and often drills into the body cavity of sea cucumber to find food or avoid enemies. The movement of the light fish in and out of ginseng is fast and funny: first, it explores the anus of sea cucumber with its small head, then curls it into the tail, then straightens its body, and then wriggles backwards until it completely drills into the parasite. It is found that there are more than seven light fish living in a sea cucumber. Light fish regard ginseng as a comfortable apartment during the day and come out to find some small crustaceans and other animals to satisfy their hunger at night. Unfortunately, when sea cucumber became the host, it not only didn't get any benefits, but also damaged its internal organs. However, we live in harmony with each other and never part. All sea cucumbers near the coast have almost no light fish lurking and parasitic, while sea cucumbers living in the deep sea generally have one or more light fish lurking in their bodies.

A few years ago, people were surprised to find that a small pure iron ball with a diameter of only 0.002 mm was hidden under the skin of sea cucumber. So far, people can't explain what benefits this small iron ball has for sea cucumbers.

Respondent: 56408923- probationary period level 1 3-22 2 1: 13.

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Sea cucumber was named by ancient China people. "Its sexual warming; Enough enemy participation ",hence the name. Sea cucumber is an echinoderm, also known as sea cucumber, which grows on rocks or seaweed at the bottom of the ocean. There are more than 800 kinds of sea cucumbers, and only more than 20 kinds are edible. The varieties of sea cucumbers vary from place to place. China's Xisha Islands and Hainan Island are rich in Plum Blossom Ginseng and Wuyuan Ginseng. Fujian and Zhejiang produce soap ginseng and light ginseng; The northern sea cucumber is only Stichopus japonicus, which is a relatively precious edible sea cucumber variety.

Observing the shape of sea cucumber from the aquarium, its shape is quite ugly. Its slender and round body is covered with meat and fat, and its surface is covered with things like meat spines. No wonder people call it "sea cucumber" vividly. On the other hand, sea cucumber is ugly, but its survival history is surprising. It appeared earlier than primitive fish and began to exist in Precambrian more than 600 million years ago. After systematic study by paleontologists, the bone fragment fossils of sea cucumber have become an important basis for stratigraphic paleontologists to divide strata and study paleogeology, and even become the standard fossils of Jurassic. More than ten years ago, paleontologists in China discovered the skeleton fragments of sea cucumber in the Permian strata in Huaying Mountain, Sichuan and Changxing, Zhejiang (more than 200 million years ago).

Sea cucumbers live in the depths of the sea and can't swim. They just crawl on the seabed by stretching their legs and muscles. The crawling speed is quite slow, 1 hour can't walk 3 meters. It was born with no eyes and no sharp weapon to scare the enemy. In this way, for hundreds of millions of years, in the ocean world where the law of the jungle prevails, how did they survive so far?

An unusually calm period

As we all know, some animals on land have the habit of hibernating. In the cold winter, the water-cooled grass withered and it was difficult to feed, so we had to hide in the nest and rely on nutrients in the body to survive. Sea cucumbers, on the other hand, choose to sleep in summer when food is abundant. Take Stichopus japonicus as an example. When the water temperature reaches 20℃, it quietly moves to the dark of the deep-sea reef, hiding at the bottom of the stone, with its back facing down. Sleep for three or four months. During this period, you can't eat or move, and your whole body shrinks and hardens until after autumn, when you wake up and resume your activities.

Strange, why do sea cucumbers hibernate in summer?

Oceanographers explained that on weekdays, sea cucumbers feed on small creatures, which are sensitive to the temperature of seawater. When the sea surface is heated, they will go upstream, and when the sea surface is cold, they will dive back to the bottom of the sea. After summer, when the sea surface gets warmer, the small creatures living in the sea will go to the upper waters to breed once a year, but the sea cucumbers living at the bottom of the sea can't follow them and are forced to stop eating. Have to hide under the stone to rest and maintain.

Special and wonderful protection technology

Facing the dangerous underwater environment and all kinds of vicious and cunning enemies, sea cucumber protects itself in a special way. Wind and waves will involve poorly attached sea cucumbers in dangerous situations. But sea cucumbers can predict the weather. When the storm came, it hid in a crack in the stone. When fishermen found that there were no sea cucumbers on the seabed, they knew that a storm was coming and quickly closed their nets and returned.

When insidious and cunning sailboats and greedy and ferocious sharks sneak up on us, the alert sea cucumber quickly sprays long sticky intestines and branch-like scuba into the body cavity, so that the strong enemy can have a full meal, but it escapes without a trace with the recoil of discharging dirt. Of course, an empty sea cucumber without an inner cavity will not die, and new internal organs will be born in about 50 days.

Sea cucumber not only has the unique skill of decontamination and confusing the enemy, but also has the function of "being in two places at once" like a starfish. Cut the sea cucumber into several sections and put it into the sea. After 3 ~ 8 months, each section will grow into a complete live ginseng. Some sea cucumbers also have the ability to cut themselves. When the sea cucumber feels that the external environment is not suitable, it can cut itself into several sections, and each section will grow into a new individual in the future. When fishermen catch sea cucumber, if they don't add salt and alum in time, it will dissolve into a pool of water.

An interesting and strange phenomenon

Sea cucumber and light fish live in harmony. This kind of light fish, also called diving fish, is small and smooth, and often drills into the body cavity of sea cucumber to find food or avoid enemies. The movement of the light fish in and out of ginseng is fast and funny: first, it explores the anus of sea cucumber with its small head, then curls it into the tail, then straightens its body, and then wriggles backwards until it completely drills into the parasite. It is found that there are more than seven light fish living in a sea cucumber. Light fish regard ginseng as a comfortable apartment during the day and come out to find some small crustaceans and other animals to satisfy their hunger at night. Unfortunately, when sea cucumber became the host, it not only didn't get any benefits, but also damaged its internal organs. However, we live in harmony with each other and never part. All sea cucumbers near the coast have almost no light fish lurking and parasitic, while sea cucumbers living in the deep sea generally have one or more light fish lurking in their bodies.

A few years ago, people were surprised to find that a small pure iron ball with a diameter of only 0.002 mm was hidden under the skin of sea cucumber. So far, people can't explain what benefits this small iron ball has for sea cucumbers.