About the real reason for the extinction of the dinosaurs, since ancient times, that is, there are many different opinions, but there is not a certain argument, so so far is still an unsolved mystery, here only some of the more well-known statements are described as follows:
I. Meteorite collision:
65 million years ago, a huge meteorite hit the Earth, making the dinosaurs, which had been on Earth for hundreds of millions of years, extinct. The theory was developed by four authors, including Dr. Louis Albarez of the University of California, Berkeley. Dr. Louis Albarez of the University of California, Berkeley, and four other scientists.
The giant meteorite was about 10 kilometers in diameter. The cratered terrain created by the impact was two hundred kilometers in diameter. The energy generated by the impact, when converted to yellow powder, is equivalent to one million billion tons (megaton). The dust spread through the atmosphere to the stratosphere. This caused the Earth to remain in a state of darkness for several months. During this period, many creatures, led by the dinosaurs, became extinct as a result.
II. The Comet Collision Theory:
The Comet Collision Theory is based on the work of the paleontologists David L. Raupp and John B. Kennedy. David Raupp and John Szepkowski. The "comet collision theory" began with the argument that "paleontological extinctions occur every 26 million years", published by the paleontologists David Raupp and John Sepkowski. Louis Albarez summarized this argument. Louis Albarez presented this argument and his theory to the astrophysicist Charles Muller. Mulla later argued that it was the gravitational pull of the Sun's half star, Nemesis, that periodically pushed the comet towards the Earth.
III. Mountain building movement:
The mountain building movement that occurred at the end of the Cretaceous period caused the swamps to dry up, and many of the dinosaurs that called the swamps home could no longer live there. Because of the change in air and plants, herbivorous dinosaurs could not adapt to the new food and became extinct one after another. When the herbivorous dinosaurs became extinct, the carnivorous dinosaurs lost their support and became extinct as well. This process of extinction lasted for 10-20 million years. By the end of the Cretaceous period, the dinosaurs were finally extinct on Earth.
Four. Climate change theory:
As a result of plate shifting, the ocean currents changed, causing dramatic climate changes. The cold climate killed the plants, and the dinosaurs were deprived of food, leading to their demise.
5. Volcanic eruption:
Because of the eruption of volcanoes, carbon dioxide was spewed out in large quantities, causing the earth's rapid greenhouse effect, which led to the death of food. In addition, volcanic eruptions cause the release of large amounts of salts, the ozone layer rupture, harmful ultraviolet radiation on the surface of the earth, resulting in the extinction of living creatures.
VI. Ocean ebb and flow theory:
According to Barker's theory, when the ocean ebbs and the land borders, organisms come into contact with each other, thus causing the extinction of certain types of organisms. For example, the kangaroo, which can survive on an island continent like Europe, was declared extinct on the South American continent when it met another species of animal.
In addition to this eat-and-be-eaten relationship, there is also the problem of transmission of diseases and parasites.
VII. Warm-blooded animals:
Some people think that dinosaurs were warm-blooded animals and therefore could not survive the cold weather of the late Cretaceous period. This is because even if dinosaurs were warm-blooded, their body temperature was still not high, probably about the same as that of a living sloth, and they could only have survived in tropical climates in order to maintain such a body temperature. At the same time dinosaurs had imperfect respiratory organs that could not adequately replenish oxygen, and while they did not have thick fur to avoid loss of body heat, they were prone to losing large amounts of heat from their long tails and feet. What makes warm-blooded animals different from cold-blooded animals is that if their body temperature drops below a certain range, they have to expend physical energy to raise it, and their bodies become weak very quickly. They are too large a body drive to enter a cave to escape the cold, so if the cold days continue for a few days, they may suffer the fate of freezing to death as they run out of energy.
VIII. Autocide said:
Some people believe that the real reason for the extinction of the dinosaurs is because they kill each other - carnivorous dinosaurs to grass-fed dinosaurs for food, meat dinosaurs increased, grass-fed dinosaurs naturally more and more less and finally disappeared, meat dinosaurs due to the lack of meat to eat, kill each other, and finally finally died together.
9. The theory of oppression:
The number of dinosaurs increased dramatically, in the case of limited plants, caused the extinction of herbivorous dinosaurs, and then the carnivorous dinosaurs, which relied on eating herbivorous dinosaurs for a living, also died because of the lack of food. (Question: Why did dinosaurs suddenly increase in number after about 200 million years of ecological equilibrium? This is the key to the theory, and has led many scholars to examine the reasons for the abnormal increase in dinosaur populations).
X. Mammalian prisoners:
In the latter half of the Mesozoic Era, there were mammalian ancestors. According to the fossil record, the mammals at that time were very small and limited in number, and it was not until the later part of the Cretaceous period that their numbers began to increase rapidly. It is assumed that they were omnivorous, feeding mainly on insects, and that these small mammals continued to eat the eggs of the dinosaurs when they found them.
(My opinion: Is this really true? If mammals overcame dinosaurs, then with the increase of mammal fossils, dinosaur fossils should gradually decrease, but in fact there is no such alternation of fossils. In other books, the real increase in mammalian fossils came after the end of the age of the dinosaurs. Moreover, dinosaur fossils disappeared all of a sudden. Therefore, the claim that dinosaurs were wiped out by mammals is not valid).
XI. Species aging theory:
It is believed that the dinosaurs were overly gigantic due to the 100 million to tens of millions of years of prosperity. In addition, the horns and other bones also appeared to be abnormally developed, thus causing great inconvenience in life, which finally led to the extinction of the species.
The most representative of the dinosaurs, Brontosaurus, with a body length of 25 meters and a weight of 30 tons, lost its ability to live due to its oversized body and slowed down its movements. In addition, Triceratops and other dinosaurs were instead on the road to self-destruction due to their ever-growing three horns and the unusually developed bones that protected their heads and other parts of their bodies.
(My opinion: Not all dinosaurs were so large, but there were also small dinosaurs that were only about one meter long. There were also dinosaurs that had bones like deer and could run very fast. But why did these dinosaurs go extinct at the same time? Furthermore, it is assumed that the abnormally developed bones and other parts of the body of a cold-blooded animal had a very favorable function in that they were able to absorb the outside temperature and release heat from the body in order to regulate the temperature of the body. From this, I am skeptical of the claim that dinosaurs became extinct due to the aging of the species).
XII. Alkaloid theory:
This theory is that during the last period of the dinosaurs' existence, that is, the Cretaceous period, flowering plants began to appear, and some of them contained poisonous alkaloids, which caused the dinosaurs to die of poisoning due to massive ingestion. The reason is that mammals are able to distinguish poisonous plants by taste and smell, but dinosaurs did not have this ability.
However, the alkaloid-containing plants did not suddenly appear in the late Cretaceous, but were seen five million years before the dinosaurs went extinct. The theory does not explain why dinosaurs survived during this period.
In addition to the above twelve claims, there are also "infectious diseases", "radiation from the universe or supernova explosion", "not on Noah's Ark", "solar system vibration" and other lesser-known claims, as for the one that is the best argument, it all depends on the idea of each person, there is no certain right and wrong, after all, the mystery of the dinosaur's demise has not yet really solved ah!
The oldest reptile fossils can be traced back to the Paleozoic era of the Pennsylvanian era (31,000,000 years ago - 27,500,000 years ago). The reptiles evolved from amphibians. Amphibians need water for their eggs to develop. Reptiles evolved egg shells that prevented water from escaping. This was a major change that allowed reptiles to live out of water.
By the Mesozoic Era, which lasted from 225 million to 65 million years ago, reptiles dominated the planet, so the Mesozoic Era is also known as the Age of Reptiles. Large reptilian dinosaurs appeared in the early Mesozoic. The herbivorous Leontosaurus and Brontosaurus were the largest terrestrial animals. Tyrannosaurus Rex was a carnivorous dinosaur. There were also ichthyosaurs that lived in the sea and pterosaurs that lived in the air.
Reptiles flourished on Earth for about 150 million years or so. The most well-known of the animals from this era are the dinosaurs. When people think of dinosaurs, they think of a huge, ferocious animal, but there were also small, gentle dinosaurs.
Dinosaurs belonged to the vertebrate reptiles, once produced in the Mesozoic era of the land marshes, neck and tail are long. The hind limbs were longer than the front limbs and had tails. Among them, there are several species of good meat-eating, several species of good grass-eating, huge body size, can be regarded as the largest of the land animals. The body size of the lower species is similar to that of the most ancient crocodiles and beaked heads, and the higher species are slightly similar to birds.
The study of dinosaurs is based on fossils. Paleontologists use their fossils to deduce their morphology and habits. According to paleontologists, dinosaurs were like living animals: some were big, some were small; some walked on two legs; some walked on four legs; some ate plants, some ate animals; some had smooth skin, some had scales or bone plates on their skin. The ****ing similarity is that all dinosaurs, had small brains and laid their eggs on land (as did all reptiles).
(1) Brontosaurus:
Some dinosaurs were very large, like Brontosaurus is an example. During the Jurassic period, the Earth's climate was warm and humid, with verdant forests everywhere, and because of this abundance of plant food, it brought about a boom in herbivorous dinosaurs, and Brontosaurus was active in the plains of what is now North America even after this time.
The weight of Brontosaurus was about thirty-five metric tons to fifty metric tons, and its thick legs were like tree trunks; its long neck, standing upright, was as tall as a seven-story building, and it could be said to be the largest animal ever to have lived on Earth. Although the body of the Brontosaurus is incredibly large, but the temperament is very gentle, usually to the temperate forest plants for food, sometimes into the swamp, due to the buoyancy of the water can reduce the heavy burden of its body, but also to avoid the ferocious carnivorous dinosaurs like Allosaurus as the attack.
(2) Three Horned Dragon:
The bone plates and fragments on the bodies of Stegosaurus and Ceratosaurus could only be used as a passive defense, and there was no way to fight back, and it was only after the appearance of the Horned Dragon that the situation gradually changed. The Three Horned Dragon was the largest of the Horned Dragons, with two spear-like horns on its head and another horn protruding between its eyes and nostrils. With such sharp weapons, even the most fearsome carnivorous dinosaurs would have to give it a miss.
(3) Stegosaurus:
The Stegosaurus, which appeared 150 million years ago, was best characterized by two rows of bony plates that rose up on its back and a tail bearing sharp spines. Stegosaurus was a herbivorous, slow-moving dinosaur, so the plates on its body and the spikes on its tail became its best defense against carnivorous dinosaurs.
(4) Aetosaurs:
The Stegosaurus was protected by bone plates, but it was still vulnerable to attack where the plates could not cover. When the Stegosaurus became extinct, the Armadillo Dragon (Armadillo Dragon), which was clad in bone plates, took its place. The Armadillo was an invulnerable tank, and even the T. rex was helpless against it.
(5) Tyrannosaurus Rex:
The Tyrannosaurus Rex (Tyrannosaurus Rex) was the largest and most brutal of the carnivorous dinosaurs, and it appeared at the very end of the Age of Dinosaurs, about 80 million years ago. The Tyrannosaurus rex's body stood fourteen meters tall and weighed about ten metric tons, and its hind feet were so thick and strong that they could even hold up a rhinoceros each.
Fossils of T. rex show that each of its teeth was as big as an adult's hand, and even its eyes were larger than a human head. Although most of its body was incredibly large, the Tyrannosaurus Rex had a pair of forelimbs that were both small and short, so short that there was no way to even get food into its mouth, and the killer dragons shared the same habits as the Tyrannosaurus Rex, and were very ferocious animals.
[6] Duck Crowned Dragon:
The Duck Crowned Dragon, like the Tyrannosaurus Rex, appeared at the end of the Age of Dinosaurs. The most special part of Duck Crowned Dragon was in its head, its flat and long jawbone, like a duck's beak, so it got a name like Duck Crowned Dragon. In the past, it was thought that Duck Crowned Dinosaur lived a life similar to that of a duck, swimming in the water and living on plants in the water. Later, when scientists studied the fossils of duck-crowned dragons, they found that they did not eat water plants for a living, but fed on trees on the shore, and the goose-crowned dragons had the same habit.
Who first discovered dinosaurs
Mr. and Mrs. Mantell
In Sussex, in southern England, there is a little place called Lewis, where 180 years ago there lived a country doctor named Mantell. Mr. Mantel was full of curiosity about nature and especially loved to collect and study fossils. When he was not practicing medicine, he often took his wife with him to climb the mountains and rivers to find and collect fossils, and his footprints were all over the surrounding ditches and dales where there were rock outcrops. Over time, Mrs. Mantel became a "friend of nature" and an expert fossil collector.
Avian dragons
One day in March 1822, the weather was very cold, but Mr. Mantell went out to see his patients as usual. Mrs. Mantel waited at home for her husband to return, always mentally wondering if he would catch cold. Then Mrs. Mantel could not sit still any longer, so she took one of her husband's clothes and went out to meet him in the direction of his clinic. She was walking along a highway that was being built, with layers of rock exposed by the steep, newly cut walls on either side of the highway. She habitually observed the newly exposed rock formations on either side as she walked, when suddenly something shiny caught her attention. "What is this?" She muttered to herself as she walked up to get a closer look. Woah! It turned out to be some strange looking fossilized animal teeth. These fossilized teeth were so big that Mrs. Mantel had never seen such large teeth before. The excitement of the discovery made Mrs. Mantel forget about giving her husband his clothes. She carefully removed the fossils from the rock formation and brought them home.
Later in the evening, Mr. Mantel returned home. He was stunned when his wife presented him with the newly collected fossils. He had seen many fossilized teeth of ancient animals, but none of them resembled such large, strange teeth.
Shortly thereafter, Mr. Mantel found many more of these teeth and associated fossilized bones near the site where the fossils were found. To find out what kind of animal these fossils belonged to, Mr. Mantel brought them to the French naturalist Gouvier, then one of the world's most famous scholars, for identification.
Truth be told, Gouvier had never seen such fossils before, nor had they been mentioned in any of the books or papers he had read, written by previous scientists. Still, Guevrier made a judgment based on his considerable knowledge of zoology that the teeth were from a rhinoceros and the bones were from a hippopotamus, and that neither of them was too old.
Mr. Mantel was very skeptical of Güvrier's identification, and he thought Güvrier's conclusions were too hasty. He decided to keep examining the evidence. From then on, whenever he could, he traveled to museums around the world to compare specimens and review data.
One day, two years later, he happened to make the acquaintance of a museum scientist working at the Royal Academy Museum in London, who was studying an iguana, a modern lizard that lives in Central America. So Mr. Mantell brought the fossils to the Royal Academy Museum in London and compared them with the teeth of the iguana in the museum's collection, which turned out to be very similar. The delighted Mr. Mantel concluded that the fossils belonged to an ancient reptile similar to the iguana but extinct, and named it "Iguana's Teeth".
Later, with the discovery of more and more fossil material, mankind's understanding of these ancient animals is also more and more in-depth, we know that the so-called "iguana's teeth" this animal is actually a member of a wide variety of dinosaur family; it is true that with the iguana as belongs to the same reptile, but it is related to the real iguana It is indeed a reptile like the iguana, but it is more distantly related to the real iguana than to any other species of dinosaur! However, according to the rules of biological nomenclature, the Latin word for the species name of the earliest scientifically documented dinosaur has not changed, and still means "iguana's teeth". Its Chinese name, however, has been translated as Avocetosaurus.
So remember: Avianosaurus is the earliest recorded dinosaur in the history of science. And don't forget the name Mantell and his nature-loving wife.
Who first discovered dinosaurs
The story of Plot-Garonne-Garonne
The story of Mrs. Mantel's discovery of dinosaurs is indeed a romantic one, and the fact that Mr. Mantel was able to explore the question of dinosaur attribution with a rigorous and factual attitude is indeed the first step in mankind's scientific study of dinosaurs and understanding of them.
But in history, human beings have long discovered dinosaur fossils, only that at that time, due to the limited level of knowledge, it was not yet possible to interpret these fossils correctly.
As early as more than 1,000 years ago during the Jin Dynasty in China, dinosaur fossils were found in Wucheng County, Sichuan Province. However, people at that time did not realize that they were the remains of dinosaurs, but treated them as bones left behind by legendary dragons.
A researcher named Harseltide of the University of Reading, England, based on the clues found in a historical novel, Mr. Milligan's Wife, after a long time of research and going through a large amount of information, has recently announced that he has finally discovered the following facts: In 1677, an Englishman named Proctor Garonne-Garonne compiled a book on the natural history of the county of Oxfordshire. In this book, Plott Garonne describes a huge fossilized leg bone found in a quarry in the parish of Caravella. Plot-Garonne-Garonne has drawn a good illustration of this fossil and points out that this thigh bone is not that of a cow, nor of a horse or an elephant, but belongs to a type of giant larger than them.
While Plot-Garonne-Garonne did not recognize the fossil as that of a dinosaur, or even associate it with a reptile, the specimen he documented in writing and depicted in an illustration has been identified by later paleontologists as the thigh bone of a dinosaur called Megalosaurus, and the discovery of this fossil preceded that of the Mantels' discovery of the avian dragon by 145 years. As a result, Harseltide believes that the province of Plot-Garonne-Garonne should have been the first discoverer and recorder of dinosaur fossils.
The origin of the name "dinosaur"
In fact, the discovery of dinosaur fossils by human beings must have a long history. Long before the Mantels discovered the avian dragon, Europeans knew that there were many huge fossilized skeletons of strange shapes buried in the ground. However, at that time, people didn't know exactly who they belonged to, so they had been mistaken for the "remains of giants". As for us Chinese, as early as 2000 years ago, we began to collect the fossils of large ancient animals unearthed in the ground for medicinal purposes, and called these fossils "dragon bones". Who can be sure that the name "dragon bone" is not connected with the discovery of dinosaur fossils?
Psittacosaurus
But it wasn't until the Mantels discovered an avian dragon and compared it to an iguana that the scientific community tentatively identified it as an extinct lizard-like reptile. As a result, the subsequent discovery of new types of dinosaurs and other ancient reptiles, the names are all related to lizards, such as "lizards like whales", "lizards of the forest" and so on. At the same time, the fossils of these ancient animals that first drew attention to them were often huge, strange and terrifying.
With the discovery and excavation of these terrifying and lizard-like fossils of ancient animals, their species accumulated more and more, and many museum scientists have begun to realize that they should be self-contained in the taxonomy of animals. By 1842, the British paleontologist Sir Owen coined a name for them in Latin, which consisted of two roots, the first meaning "horrible" and the second meaning "lizard". From then on, "horrible lizards" became a collective name for a large group of reptiles that are related to each other to a certain extent, but behave in various ways. We Chinese, with our imagination and our power of generalization, translated the Latin name into "dinosaur".
Mamenchisaurus
Now we know that the dinosaur family was full of terrifying behemoths, but there were also some small, cute little things. If you go to the Beijing Zoo not far west of the Chinese Ancient Zoological Museum to take a look, from the length of less than 1 meter parrot-billed dinosaur to the body of up to 22 meters long Mamenchisaurus, different sizes and forms of various dinosaurs will make you have a more comprehensive understanding of the world of dinosaurs.
Now we also know that dinosaurs were not lizards at all. Although they belong to the reptile, but in the reptile family, dinosaurs and lizards are quite far from each other!
From the dexterous Archaeopteryx to the brutal Tyrannosaurus rex
--Meat-eating theropod dinosaurs
Early Jurassic dominance--Dinosaurus bisognathus
In 1942, a species of dinosaur was found in early Jurassic strata of the United States, in the state of Arizona. Jurassic strata in Arizona, USA, in 1942, a large theropod dinosaur was discovered, which scientists named Dilophosaurus because of a pair of thin, V-shaped bones on top of its head.
The Dilophosaurus
The body of the Dilophosaurus was stout, with a tall skull, well-developed jaws, and a large gaping mouth full of teeth that looked like sharp knives, with small serrations on the front and back edges of the teeth, features that showed that it could have torn apart any prey it caught and then swallowed large chunks of meat into its stomach. In addition, the skull of the dromaeosaurus had holes behind the eyes for better attachment to the muscles that held the jaws in place, so the dromaeosaurus must have had a very powerful bite. Scientists speculate that the dromaeosaurids may have been some of the most brutal and ferocious predators in the early Jurassic ecosystem.
Dinosaurs buried with archaeopteryxes
Dinosaurs had strong hind limbs and sharp claws on their feet that could be used to catch and rip apart their prey. 200 million years ago or so, dinosaurs were often found on the high ground between rivers and lakes or in the jungles, hunting down a wide variety of vegetarian animals. They may have preferred to live in solitude, or they may have waited for the right moment to sneak up on their prey in an undetectable place, or they may even have fed on the carcasses and rotting flesh of animals that had died for various reasons, as modern hyenas do.
The fossil of a double-dragon was also found in Jinning County, Yunnan Province, China.
In August 1987, a dinosaur excavation team from the Kunming City Museum in Yunnan Province unearthed a fossilized Yunnanosaurus belonging to the Archaeopteryx group in Xiyang Township, Jinning County. The news attracted people from all over the world to come and watch. The people here are all Yi compatriots who have never heard of any dinosaurs. But when they saw a piece of fossil, some of them felt that this bone-shaped stone was déjà vu. Some told the excavation team that they had also seen such stones on the slopes of Mugang Ham Village in the Xiyang Township.
The team followed the tipster to Mukpoh hammer village, where a string of dinosaur vertebrae was exposed in a small gully. They decided to excavate here. A few days later, a shocking scene appeared. It turned out that there were two dinosaurs here! And there were two complete dinosaur skeletons twisted together, one of which was a palaeopod dinosaur, while the other was a carnivorous dinosaurs, with the latter's large mouth biting right into the former's tailbone. Scientists according to the fossil of this buried condition speculation, the two dinosaurs may have two causes of death: one is they are in a fight of your death and I live in the two defeated and both died; another may be the ancient foot dinosaur has been dead for many days, the body of the meat has been corrupted and deteriorated, and the hungry beasts foot class just fill up their stomachs, did not expect to eat because of the meat of the corrupted and deteriorated dinosaur feet and poisoned to death. From the calm posture of the two, the latter is even more likely.
The Chinese diplodocus was the largest meat-eating dinosaur of the early Jurassic period, measuring nearly 4 meters in length with a sharp, long mouth. It had a cleft in the front of its upper jaw that allowed the front jawbone to move. Scientists speculate that its favorite food was probably the entrails of other animals, because its pointed beak could reach into the abdominal cavities of dead animals, and the two thin, plate-like crowns on the top of its head could act as a support for the walls of the cavity as the head reached into the belly of the carcass.
Dinosaurs were also members of the circum-Tethys fauna, so the species found around the world are similar. Their fossils have also been found in modern Antarctica, suggesting that Antarctica, which is now freezing, was a warm place for dinosaurs at the time
The Great Extinction
The fossils of dinosaurs have been discovered in recent years, and new species have been found, with a group of scientists delighting in their research, and with a generation of young children and their parents intensely interested in the mysterious creatures of the distant past. The children and their parents are strongly interested in these mysterious ancient creatures. Why is this?
Extinction at the end of the Mesozoic
This is because many dinosaurs were too big compared with us humans, so we all have to think, why did they grow so big? It is also because there are so many different kinds of dinosaurs, and their appearance is so strange that we can't help but wonder how many members there are in this huge family of dinosaurs.
There is a more important reason, that is, so many once vast, angry life on the earth of the dinosaurs, why one does not stay from the earth disappeared, did not leave their descendants, but left us a difficult to solve the mystery. This mystery will always inspire us to explore and seek knowledge.
Now we know that the dinosaurs became extinct 65 million years ago. And at that time, not only ruled the earth for more than 100 million years of various kinds of dinosaurs all extinct, the same tragic fate also at the same time to the earth's land, sea and sky living in a variety of other creatures. In this disaster, the extinction of the serpent-necked dragon and other marine reptiles, pterosaurs and other flying reptiles, colorful lizards and other reptile relatives of the dinosaurs on land, there are chrysanthemums, argillaceous and other marine invertebrates; as for the micro-zooplankton in the ocean, calcareous planktonic foraminifera and calcareous micro-zooplankton was also almost wiped out. After this great catastrophe, about 50% of the living genera and almost 75% of the living species on the earth at that time disappeared from the earth forever.
This was a great extinction, a great catastrophe. As a result of the extinction, the landscape of the living world on Earth changed radically around the time of 65 million years ago. The extinction marked the end of the Mesozoic Era, and the geological history of the Earth entered a new era, the Cenozoic Era.
Scientists have worked tirelessly to analyze and study all the clues that can be found so far, and have put forward a variety of theories to explain this great extinction phenomenon. But so far, they have not found a 100% correct answer about the cause of this extinction.
Perhaps such an answer awaits you.
In the following, we will introduce some of the theories and theories about the cause of the extinction of the dinosaurs, i.e., to provide you with some basic background knowledge, and hopefully to provide you with some inspiration to discover a better explanation.
The theory of asteroid impact
In 1980, in a scientific seminar, American geologist Alvarez and others based on their research results, image vividly declared a paragraph happened 65 million years ago in a thrilling story: a sunny afternoon, the sun shines under the tropical scrubland, many different kinds and forms of dinosaurs calmly as usual or strolling by the lake. usual, either strolling by the lake or foraging in the water; at the edge of the forest, a duck-billed dinosaur that had just hatched an egg was pacing back and forth by the nest; in an open field, a Tyrannosaurus rex was preparing to pounce on a huge Triceratops ......
Suddenly, a loud bang that had never been heard before shattered the quiet of the world. A meteor several kilometers in diameter slammed into the Earth. This collision was a big deal, an explosion equivalent to the power of tens of thousands of atomic bombs occurred in an instant. It was an unanticipated asteroid that collided with the Earth with an impact force of up to 1015 tons of energy generated by the explosion of TNT. Rolling with dust a huge mushroom cloud quickly rose up into the sky before dispersing and eventually enveloping the entire planet. Soon the dinosaurs were invisible to each other, for the black cloud covered the sky and there was no sunlight during the day. This horrible condition lasted for a year or two. The photosynthesis of the plants was interrupted, and as a result, they withered and died in large numbers. Vegetarian plant-eating dinosaurs died one after another. Later, the meat-eating dinosaurs also became extinct due to the loss of food.
This story is the essence of the theory that the great extinction of dinosaurs was caused by the impact of an asteroid on the earth. It has been continuously supported by many scientists since then. Some scientists even believe that the Earth not only experienced a larger planetary impact during this period, but also suffered many smaller, but still seriously life-threatening asteroid impacts in quick succession, among which can be confirmed in the Caribbean Sea and the U.S. state of Iowa found traces of planetary impacts.
Evidence for this hypothesis also comes from the presence of an amino acid in 65-million-year-old sediments found around the world. This amino acid contains high levels of iridium, which is found in large quantities in certain celestial bodies and is not supposed to exist at all on Earth. This iridium-rich layer has been found successively in many parts of North America, Europe and Australia, and was also discovered a few years ago in the Gamba region of Tibet in China.
Some scientists believe that the explosion made all the dinosaurs extinct. But some scientists believe that only 70 percent of the dinosaurs were extinct at the time, while some other dinosaur species barely escaped the disaster, but in the following millions of years and gradually extinct. This latter theory is not without merit, as some dinosaur bones are still found in strata formed after this event 65 million years ago. For example, dinosaur remains have been found in the strata of New Mexico, U.S.A., up to and including 60 million years ago. Fossils of Triceratops have also been found in the Cenozoic tundra of Alaska. These phenomena seem to indicate that some dinosaurs still struggled to live for millions of years after the big bang caused by the asteroid impact on the Earth, before finally going extinct due to a lack of adaptation to the new climate and new environment.
Latest theory -- large-scale undersea volcanic eruptions
Antonio Zigicchi, a renowned Italian physicist, recently suggested that the cause of the dinosaur extinction was probably a large-scale undersea volcanic eruption.
Professor Zigicchi argues that at the end of the Cretaceous period, a series of large-scale volcanic eruptions occurred under the oceans of the Earth, thus affecting the thermal balance of the sea water, and in turn causing changes in the land climate, and therefore affecting the survival of animals such as dinosaurs, which needed a lot of food to survive. His reasoning is that modern undersea volcanic eruptions are well known for their impact on the oceans and the atmosphere, only to a much lesser extent than the undersea volcanic eruptions that occurred 65 million years ago.
Professor Zikicki argued that in the past, the scientific community had known very little about undersea volcanic eruptions, and that there was now a need for in-depth research into this phenomenon, which was seriously affecting the Earth's environment. He cited the example of Greenland, which used to grow dense vegetation, but