In ancient times, there was Gou Jian who lived on the grass and tasted the gall, while Han Xin was humiliated by his crotch. Now there is a lung fish who swallows its tail to survive. But in fact, in ancient and modern times, Gou Jian and Han Xin can’t compare with our heroes today! Today, we will take you to know about this “cruel living fossil” 400 million years ago – lung fish!
Dipnomorpha is a freshwater fish that lives on the other side of the Atlantic Ocean in South America. After 400 million years of biological evolution and elimination, there are only six species of wild lungfish, including Australian lungfish, American lungfish, longlungfish, protopteris, Shihua lungfish and East African lungfish. The common fish we see on TV and on the Internet are African lungfish, which are mainly distributed in the watersheds near the equator of Africa.
Lung fish can grow up to 1-2 meters, which belongs to the larger species of freshwater fish. Its appearance is similar to catfish, but it is not like catfish. Its whiskers grow on both sides of the lips. Lung fish’s “whiskers” grow on the fins, so it is also called “paired fins”. The paired fins of lung fish have the strength to support their bodies. After the observation of researchers, they found that lung fish really can Walk on all fours! Of course, this is also related to the fact that the buoyancy of water appropriately reduces its own gravity.
“Special function” of lung fish
1. Lungfish live a long life
If we talk about the history of lungfish, it’s really three days and three nights! In fact, lungfish is a kind of creature that lived on the earth earlier than dinosaurs. Its earliest fossil record can be traced back to the early Devonian. In the early Devonian, lungfish mostly grew into one shape – long in size, with neat scales and a pair of paired fins like leaves. As time goes on, lungfish living in different environments have undergone a variety of changes. In the late Devonian, lungfish grew into one shape In the Devonian and Carboniferous, the group of lungfish had been “brothers and strangers”! Their head length, spine structure and tooth plate structure have shown high specificity. The living area has gradually changed from ocean to fresh water.
By the 19th century, lung fish had been served on the table by local people, but at that time, because of its pink meat quality, it was often mistaken as a kind of salmon. It was not until Australian Museum curator Kraft discovered the lung of “salmon” when eating “salmon” that lung fish was able to “redress the injustice”.
As the saying goes, “the king of thousands and the turtle of 80000 years”, the tortoise is often regarded as the representative of longevity, because they often stay in one place and do not move. Some of the life habits of lungfish are similar to that of the tortoise, and they can stay in one place for several months and do not move as much as possible. As a result, lungfish has become the freshwater fish with the longest life record – 90 years. The world record was set by an Australian lungfish living in the Chicago aquarium. It is affectionately known as “grandfather”.
2. Fins function as limbs
When it rains, African aborigines walking along the river bank will see a strange scene – a fish is walking along the edge of the muddy river bed on all fours! Actually, that’s the copula of the lungfish. African lungfish and South American lungfish are evolved from the subclass lungfish. The paired fins of African lungfish degenerate, like two thin and long whips, while the paired fins of South American lungfish degenerate into two short appendages, like two chicken legs.
Some paleontologists and evolutionists have discovered a new continent in lungfish. By comparing lungfish with living quadrupeds, they found that the bones of lungfish appendages are very similar to the formation of human early limbs. Connected to the body is a large bone, similar to the humerus of the human arm or the femur of the thigh, followed by two parallel bones, similar to the ulna and radius of the human arm or the tibia and fibula of the lower leg. At the top of the bone is connected with many small branches, these small bones through the fascia connection to form the fin we see! This kind of structure has to remind us of the palm and the sole of the foot. How can such an amazing discovery not inspire biologists! After all, a large number of biologists hold the view that humans may have evolved from fish.
3. It can breathe with both lungs and gills
The biggest secret to help lungfish live to the age of 100 is actually its body structure. The body structure of lungfish is more like amphibian than other fish nowadays. Its heart is like human heart, with two ventricles but no atrium. The arterial and venous blood of lung fish exchange here.
Lungfish have two respiratory systems, one is the lung and the other is the gill. The two respiratory systems can work simultaneously and separately. When a lungfish sinks underwater, it mainly breathes with its gills, but after half an hour, it needs to surface and breathe fresh air with its lungs, otherwise it may become the first “drowned fish” in biological history!
Both South American lungfish and Australian lungfish have a pair of lungs, while African lungfish only have one lung. Don’t underestimate this lung. Dissection shows that the lung of lungfish almost occupies the whole body cavity.
The two lungs of American lungfish are connected with the esophagus and glottis respectively, and the gills and gill blood vessels degenerate. In fact, the two lungs of lungfish are their swim bladders. The swim bladders of common fish can only be used to help float and sink and maintain balance. The opening between the swim bladders of lungfish and the esophagus is called the inner nostril, through which the air and carbon dioxide enter and exit, and exchange in the alveoli. The exchange of hypoxic blood and hyperoxic blood can be realized Here, as it flows through the ventricles, the arterial cones have valves that separate the blood from the lungs from the gills.
When some scholars analyzed the anatomical structure and body fluid composition of lungfish, they found that lungfish had epiglottic cartilage and pituitary structure, and the secretion of lens protein, hormone components, bile salts and other body fluids from pituitary were very similar to the structure and body fluid components of amphibians. This seems to provide a more complicated basis for human evolution.
2、 The strongest feature, dry season can drill into the soil dormancy
As we all know, the living environment in Africa and South America is relatively poor. In addition to the predation of all kinds of organisms in tropical rainforests, fish also suffer from natural disasters – dry season. Once the dry season comes, the sun’s baking will consume the water into the small rivers. Freshwater fish can’t escape the nightmare of water loss except running around. The secret of lung fish’s longevity is that they can survive in the dry season and use their lungs. When the water in the swamp dries up gradually, lungfish will dig a deep hole in their head and even fins to bury themselves. The skin of lungfish will secrete a special kind of mucus, which will become firm as time goes on, like a protective shell, which is firm and can exchange air with the outside world.
It maintains a very special shape, like a ring, end to end. It maintains this posture, does not eat, does not drink, has been insisting for six months, during which it completely uses its lungs to breathe, when it “builds” its own strong shell, it will specially leave a hole in the mouth that goes straight to the outside world to absorb the fresh air from the outside world. Under the perfect conditions of laboratory construction, lungfish can maintain the state of “summer sleep” for four years! I have to say that if this kind of state similar to “freezing” can be realized in medicine, will many patients with incurable diseases have the hope of “living”?
In fact, even if lungfish don’t move like this, it’s not enough to rely on their own fat accumulation during the rainy season to maintain a six-month summer sleep. At the end of the dry season, biologists dug lung fish out of their own muddy nests and dissected them to find that the stomach of lung fish actually has its own body tissue! It turns out that when the lung fish’s own fat accumulation is not enough to support their consumption, the lung fish will devour their tail, from the caudal fin to the muscle, nibbling bit by bit, in order to meet their body’s energy needs. I have to praise “cruel man”!
After six months of dry season, rain fell again on the land of Africa, the dry river bed was moistened, and the lungfish woke up from the soil and lived a normal life again.
3、 The lungfish finally failed to escape the clutches of the African aborigines
Our flower growers have a long history of food culture, which is broad and profound. After watching it patiently, our friends can no longer help asking, “what is a lung fish? Can you eat it? ” Xiao Bian wants to tell you! Lung fish not only can eat, but also special! No! Good! Eat!
Welcome to today’s egg segment: lung fish canteen.
Do you remember what I told you in the previous article, when a lungfish sleeps in the summer, it will leave a small hole for itself to communicate with the outside world and breathe fresh air? This small hole can make Enron sleep lung fish suffered a big disaster! Smart African aborigines are using this small hole in the soil to find traces of lungfish and dig it out of the deep buried soil! It’s just like the people on the beach chasing the sea.
The most important feature of African cuisine is that they are good at maintaining the original flavor of the ingredients, which has been brought into extraordinary play in the process of cooking lung fish!
They dug out the lung fish. Instead of scraping the scales to remove the internal organs, they would put the lung fish into a basin of clean water. The “naive” lung fish thought that the rainy season was coming ahead of time, and happily carried out material exchange inside and outside the body. After the internal dirty things of the lung fish had been emptied, the African aborigines put the lung fish into the already mixed flour paste, sprinkled with salt, cumin and other spices Put on the fire and bake on the spot!
Oh, that’s sweet! The children next door are crying! However, this lung fish has not entered our country. If it comes to our country, we will fry it and treat it well!