Hello everyone, do you know the oldest creature in the world that still exists today? The Earth has experienced five mass extinctions, each of which has extincted more than 70% of the organisms, more than 90% of the dead in severe cases, and the most serious is the third time, more than 90% of the organisms are gone. Then the representative of extinct organisms is dinosaurs, the extinction of dinosaurs has not been conclusive, it is estimated that an asteroid hit the earth caused.
At present, the reasons for the extinction of organisms are mainly inferred from objective factors. The extinction caused by subjective factors is difficult to find archaeologically. Although almost all species go extinct at every mass extinction, there are always a few species that survive, and some species have not gone extinct after several mass extinctions. Whether it is high temperature or cold or asteroid hitting the earth, it can survive for billions of years until today. They are the oldest inhabitants of the earth, so they are called living fossils.
The first living fossil.
platypus.
The platypus is one of the most special mammals. Although it is a mammal, it is oviparous. It has no close relatives in this world. There is only one species of platypus. The oldest platypus fossil found so far is found in the Cretaceous strata of Australia, and some people say that platypus lived in the same era as dinosaurs. Then it is inferred that it may have appeared 200 million years ago. Platypus is currently a critically endangered species among endangered species and is at risk of imminent extinction. When the platypus was first discovered in the 18th century, British biologists thought it was a prank, and when they saw the platypus specimen, they thought that who had sewn such a thing in a prank, and he looked for a suture between the mouth and the head on the specimen, and did not find out that there was really such a creature. The average lifespan of platypus is about 11 years in the wild, while the longest in captivity can reach 17 years. They usually live mainly in the water. Feeding on some small fish, shrimp, fish, shellfish, its longest breath holding time is only more than 40 seconds. When it finds food underwater, it does not rely on sight, does not rely on hearing, does not rely on smell, does not rely on taste or even touch. It relies on electromagnetic induction. Mammals have electromagnetic induction in the only way they and dolphins.
And the platypus is also one of the few poisonous mammals, its hind feet on the growth of a thorn, this thorn in its estrus period is poisonous, and the toxicity is very strong, pierced to cats, dogs and dogs will die at once, although people can not die immediately, but will hurt for many months. Known poisonous mammals also include groove-toothed shrews and skunks.
The second living fossil, the beaked lizard,
It is a very old lizard, currently found only in New Zealand, although it is called a lizard, but it is not the same population as all other lizards on the earth today, it is a separate species, and it is a very old species. Its bones, whether it is internal organs, have retained a very ancient state and have not evolved. This lizard is very pronounced as an intersex alien creature. What is a sexually alien organism is a creature that can distinguish male and female without going through the genitals. For example, roosters and hens, people are also sexually alien creatures, and men and women can be distinguished at a glance. Males with beaked lizards can reach up to 60 cm in length, while females are the largest and not half as males. So why the same organism has such a big difference between the sexes, the study found that one of the main reasons is heterosexual selection. It is currently speculated that this beaked lizard first appeared 2.2 billion years ago, which means that it and the ancestors of dinosaurs, the earliest batch of dinosaurs, appeared at the same time. But the dinosaurs are extinct, and it's still there. Moreover, the beaked lizard has not changed at all for more than 200 million years, retaining its most primitive state. The beaked lizard can move its two eyes alone, like a chameleon, and each eye has two retinas inside, one dedicated to seeing things during the day and one specifically for seeing things at night, which is very advanced. It has very good eyesight during the day and night. Another very special thing about the beaked lizard is that it has a real third eye.
And the third eye can still be used, its third eye has a retina, can sense light, and this eye has nerves connected to the brain will transmit information to the brain, exactly what it uses this eye to see, it is not yet known.
The third living fossil. It's speartails
Speartail fish is also called Ratimi fish, Latimai is the name of the person who found this fish, is a staff member of the South African Museum, this fish was originally thought to have been extinct tens of millions of years ago, as a result, in 1938 when the fishermen in South Africa were fishing in the western Indian Ocean, they hit a bunch of fish, one of which was this fish, but the fishermen did not know at the time, Ratimi in the museum collection of specimens, found this fish in the fish market, he is very knowledgeable about fish, but such a fish he has not seen, He felt that this fish must be a new breed or a special species. Immediately find someone to make it into a specimen, and then contact the British experts, at that time there was no network, there was no convenient means of transportation, the British experts came to South Africa after a year, saw the fish specimen was amazed, said that this is definitely a specimen from 200 million years ago.
Because this fish looks exactly like the fish of ancient times. It is now known that this fish may have lived as early as 400 million years ago. That is to say, it has not changed in four hundred million years. For example, it has 8 fins, and now the fish does not have as many fins. Its whole body is a fin, and it has a very large head, up to two meters long, weighing more than 100 kilograms, and the bones of the whole body are very soft, but there are thick scales on the outside, especially hard, like armor. This fish usually lives in the deep sea, but it has a difference with most deep-sea fish, that is, its vision is very good, the deep sea is particularly black and can't see anything, so the fish living in the deep sea basically have their eyes degenerated, but its eyes are particularly good. But also found that this fish and most of the current fish are different from a feature, that is, how it can swim, can swim sideways, upside down to swim.
The fourth living fossil, the horseshoe crab,
It doesn't look very different from modern life on Earth, but it looks almost exactly like the ancient trilobite, especially its larvae look like trilobites.
It's just that the trilobite has been extinct for a long time, and the horseshoe crab can survive, and like most ancient creatures, it has thick armor, which looks very scary, but it is harmless to people. It mainly eats some shell fish and shrimp as food. It is also a sexual alien creature, the female is particularly large, the male is particularly small, the current known horseshoe crab appeared on the earth 450 million years ago, and it looks like this, its fossils seem to have just been set in. The current problem with the horseshoe is that it may not be able to withstand this "sixth mass extinction". It is currently an endangered species that is extinct, mainly due to human persecution. The blood of the horseshoe crab is blue, the blood of most of the creatures on our earth is red, the main component of the blood contains iron ions, and the blood of the horseshoe crab is blue, its blood contains copper ions, in fact, its blood is transparent when it is in its own body, and when it bleeds, it is oxidized and becomes blue.
Research found that the horseshoe crab has no immune system, the horseshoe crab has lived in this earth full of bacteria and viruses for so many years without an immune system can survive, itself is a very incredible thing, and later research learned that it is because its blood is not the same, its blood can trap bacteria and viruses, anything harmful to the body Its blood can be trapped, which ensures that it will never be attacked by the outside bacterial virus and die, this blood is equivalent to its universal immune system. Studies have also found that its blood can be used to find cancer lesions, so the blood of the horseshoe crab is valuable. Later, people began to hunt the horseshoe crab in large quantities and draw its blood. After years of hunting and blood draws, the number of horseshoe crabs is currently decreasing rapidly. Now the most expensive liter of blood can sell for $15,000, also known as liquid gold. And nearly a year of research is preparing to make the blood of horseshoe crabs into a drug to treat AIDS.
The last one is the oldest and most prevalent living fossil on Earth, cyanobacteria.
Cyanobacteria is a very old bacterium. Another ancient bacterium is a close relative, that is, E. coli. The survival range of cyanobacteria is very wide, as long as there is water in the place where there is basically cyanobacteria, like rivers, lakes and seas, it is needless to say, above the iceberg, hot springs have cyanobacteria. Cyanobacteria can withstand very high temperatures, and cyanobacteria are single-celled prokaryotes that are invisible to the naked eye. At present, the fossil of cyanobacteria has been found in the fossils of 2.2 billion years ago, so it has been alive on Earth for at least 2.2 billion years, and it is now believed that blue is likely to be the earliest organism on Earth to obtain photosynthesis and produce oxygen, photosynthesis is very common in most plants, and organisms with chloroplasts can convert light and carbon dioxide and water into glucose, oxygen and water.
Photosynthesis is a mechanism that turns inorganic matter into organic matter through light, and turns light energy into biological energy, which is very magical. And in fact, most of the oxygen on the earth is not produced by plants, but through cyanobacteria, so fewer plants may not directly affect the composition of the earth's atmosphere, but if cyanobacteria are gone, humans and all organisms that need oxygen will face extinction.