The reasons for the extinction of dinosaurs briefly. Dinosaurs: how did they become extinct? When did the dinosaurs go extinct?

Dinosaurs are extinct! This is perhaps the only fact about them that all scientists agree on. But there is still debate about the reasons for the disappearance of giant lizards. The popular belief is that their mass death was caused by the collision of a giant asteroid with the Earth. However, there are many other interesting proposals that may complement the generally accepted theory or consider alternative views. Today we will talk about why dinosaurs became extinct.

When did the dinosaur extinction occur?

It should be noted that the extinction was not instantaneous, as some films and television shows usually present to us. Even if we start from the theory of the collision of the Earth with an asteroid, then after that all the dinosaurs did not die immediately, but the process had already been started...

Extinction began at the end of the so-called "Cretaceous"(about 250 million years ago) and lasted about 5 million years (!). During this period, many species and plants disappeared.

However, dinosaurs were the dominant species on Earth for quite a long time - about 160 million years. During this period, new species disappeared and appeared, dinosaurs evolved, adapted to climate change and were able to survive several mass extinctions, until something happened that led to their gradual and final death.

For reference: “Homo sapiens” lives on Earth for only 40 thousand years.

Who survived the extinction?

Climate changes on Earth during the Cretaceous period reduced the diversity of life, but the descendants of many of those species today delight us with their presence. These include crocodiles, turtles, snakes and lizards.

Mammals also did not suffer much, and after the complete disappearance of dinosaurs they were able to occupy a dominant position on the planet.

One may get the impression that the death of living beings on Earth was selective, and that precisely those conditions were formed in which dinosaurs could not survive. At the same time, the remaining species, although they suffered greatly, could continue to exist. These thoughts greatly excite the minds of fans of various conspiracy theories.

By the way, the word “dinosaur” is literally translated from Greek as “terrible lizard.”

Versions of dinosaur extinction

To date, it is still not known for certain what exactly killed the dinosaurs. There are many hypotheses, but not enough evidence. Let's start with the asteroid version, which was greatly popularized and largely distorted by the media and film makers.

Asteroid

In Mexico there is the Chicxulub crater. It is believed that it was formed precisely after the fall of that ominous asteroid that triggered the mass extinction of the dinosaurs.

The asteroid itself caused enormous destruction in the area of ​​its impact. Almost all life in this area was destroyed. But the rest of the inhabitants of the Earth suffered from the consequences of the fall of this cosmic body. A powerful shock wave passed across the planet, clouds of dust rose into the atmosphere, dormant volcanoes awoke, and the planet was enveloped in dense clouds that practically did not let in sunlight. Accordingly, the amount of vegetation, which was a source of food for herbivorous dinosaurs, decreased significantly, and they, in turn, allowed predatory dinosaurs to survive.

By the way, there is an assumption that at that time two celestial bodies fell on our planet. A crater was found at the bottom of the Indian Ocean, the appearance of which dates back to the same time.

Those who like to refute everything question this hypothesis. In their opinion, the asteroid was not large enough to trigger a series of cataclysms. In addition, both before this event and after, other similar cosmic bodies collided with the earth, but they did not provoke mass extinctions.

The version that this asteroid brought microorganisms to the planet that infected dinosaurs also exists, although it is not so likely.

Cosmic radiation

Continuing the theme that it was space that killed all the dinosaurs, it is worth considering the assumption that it led to this gamma ray burst close to the solar system. This happens due to a collision of stars or a supernova explosion. The flow of gamma radiation damaged the ozone layer of our planet, which led to climate change and mutations.

Volcanic activity

We have already mentioned that the asteroid could provoke the awakening of dormant volcanoes. But this could have happened without his participation, and the consequences would still have been sad.

A significant increase in volcanic activity has led to ash in the atmosphere has partially limited the amount of sunlight. And then - the onset of volcanic winter, a decrease in the number of plants and a change in the composition of the atmosphere.

Skeptics have something to say in this case too. Many scientists believe that the changes caused by abnormal volcanic activity were gradual, and dinosaurs had a high ability to adapt, which helped them survive the vagaries of nature. So why couldn't they adapt this time? Unanswered question.

Sharp decline in sea levels

This concept is called "Maastricht regression". The only connection between this event and the extinction of the dinosaurs is that everything happened around the same period. In addition, previous great extinctions were sometimes accompanied by changes in water levels.

Food problems

There are two options: either due to climate change, dinosaurs simply could not find enough food for themselves, or plants appeared that killed the dinosaurs. It is believed that they spread on Earth flowering plants, containing alkaloids that poisoned dinosaurs.

Change of magnetic poles

This phenomenon happens periodically on our planet. The poles change places, but the Earth remains for some time without magnetic field. Thus, the entire biosphere becomes defenseless against cosmic radiation: organisms die or mutate. Moreover, everything can last for thousands of years.

Continental drift and climate change

This hypothesis suggests that dinosaurs, for some reason, could not survive climate changes that were caused by continental drift. Everything happened rather prosaically: temperature fluctuations, death of plants, drying up of rivers and reservoirs. It is obvious that the movement of tectonic plates was accompanied by increased volcanic activity. Poor dinosaurs were simply unable to adapt.

Interestingly, rising temperatures may have influenced the formation of dinosaurs in eggs. As a result, only young of the same sex could hatch. A similar phenomenon is observed in modern crocodiles.

Epidemic

Insects preserved in amber can tell scientists a lot of interesting things about ancient times. In particular, it was possible to find out that many dangerous infections began to appear precisely during the extinction of the dinosaurs.

We already know that dinosaurs could adapt to climate change, but their underdeveloped immunity could not protect them from a deadly disease.

Theory of controlled evolution

It should be immediately noted that this theory is popular in conspiracy circles. These guys believe that some other intelligence is using our planet as a platform for experiments. Probably this “mind” studied the features of evolution using the example of dinosaurs, but the time has come to clear the experimental site in order to begin the same research, but with mammals in the leading role.

Thus, extraterrestrial intelligence immediately clears the Earth of dinosaurs and begins a new stage of the experiment, the main object of which is us - people! Just some kind of REN-TV. But we have to admit, conspiracy theorists skillfully present everything and do a good job of refuting other theories.

Dinosaurs vs mammals

Small mammals could easily destroy the toothy giants. Scientists do not rule out fierce competition between them. Mammals turned out to be more advanced in terms of survival, it is easier for them to get food and adapt to the environment.

The main advantage of mammals was the difference between their method of reproduction and the method of reproduction of dinosaurs. The latter laid eggs, which could not always be protected from the same small animals. In addition, the small dinosaur needed a huge amount of food to grow to the required size, and food became increasingly difficult to obtain. Mammals were carried in the womb, fed with mother's milk, and then did not need too much food. Moreover, there were always dinosaur eggs under our noses, which could be capitalized unnoticed.

Coincidence of factors

Many scientists are inclined to believe that one should not focus on any one reason, because dinosaurs were very tenacious and over millions of years withstood many surprises from nature. Most likely, climate change, food problems, and competition with mammals are to blame. It is possible that the asteroid became a kind of control shot. All this together created exactly the conditions in which dinosaurs could not survive.

Are humans at risk of extinction?

Dinosaurs lived on Earth for millions of years, people - only a few tens of thousands. During this relatively short period, we were able to create a reasonable society. But this hardly protects us from extinction.

There are quite a wide number of versions of the disappearance of humanity, ranging from global disasters and epidemics, and ending with the same cosmic threat in the form of asteroids and star explosions. However, people today can easily cease to exist - the reserves of nuclear weapons on Earth are more than enough for these purposes... True, some people can still be saved if we have time

For more than 15 years, the University of Tübingen, one of the oldest educational institutions in Germany, has operated the Children's University, where the most curious can get answers to any complex questions from real professors. In order for as many children as possible to learn what modern science is studying, scientists published their lectures in the form of books. Now they are also in Russian. If your child 7-8 years old and older is interested in volcanoes, dinosaurs or knights' castles, these books are a godsend. This time - about dinosaurs for children.

At the beginning of the Mesozoic era, our Earth looked completely different from what it does now. At that time, there was only one continent on the planet - Pangea, washed by a giant ocean. On this palm- and fern-covered supercontinent, new creatures appeared about 243 million years ago - small reptiles that moved deftly on two limbs. We call them dinosaurs.

Dinosaurs looked very different: some wore shells, others had spines, others had horns, and others had long protrusions on their spines that resembled a sail. Some dinosaurs walked on two legs, others walked on four. Some ate meat, others ate plants, and others were omnivores.

About 150 million years ago, these hardy lizards, perfectly adapted to the conditions of their habitat, were the real masters of our planet. And it seemed that nothing threatened them...

The brachiosaurus was as tall as a bell tower and weighed as much as twenty elephants. Supersaurus was more than 30 meters long, which is the height of a 10-story building. The earth shook under the steps of this monster. It seemed that he had no one and nothing to fear. The Tyrannosaurus was a real monster: a head the size of a calf, in its mouth there were sharp, long, curved teeth. The Tyrannosaurus had the strongest muscles; even the best runner in the world could not compare with it in speed. None of the modern animals, be it a tiger, a lion or an elephant, would have the slightest chance of coping with him. But who then managed to defeat him?

And yet the fact remains: dinosaurs ceased to exist. During the Late Cretaceous period, many millions of years before the appearance of humans, dinosaurs began to decline in numbers, and about 65 million years ago they completely disappeared.

Many scientists and adventurers went in search of dinosaurs. Over the past century, expeditions have scoured the planet's jungles and other impenetrable areas in hopes of finding at least one surviving fossil monster. But none of these attempts were successful. But the remains of dinosaurs were found in a variety of places. Thus, according to American paleontologist Peter Dodson, 3,000 almost complete dinosaur skeletons are stored in US museums alone. And among them there is not a single one younger than 65 million years old.

It would seem that dinosaurs had no equal in their ability to survive, and they inhabited the planet for an incredibly long time. However, at some point they gave way to another species, whose representatives previously trembled with fear as soon as they saw a dinosaur on their way. These animals, no larger than a cat, benefited when the dinosaurs went extinct. Apparently, their body was covered with fur, and they themselves resembled either squirrels or shrew mice.

Their babies did not hatch from an egg, like dinosaurs, but emerged from the mother's womb, after which the mother fed them with milk. For this feature, scientists called them mammals (mammal is an outdated name for milk) and separated them into a separate class of animals, to which humans also belong.

Why did these small, easily vulnerable animals spread throughout the planet, while strong, powerful dinosaurs, on the contrary, became extinct? To answer this question, you must first remember that the extinction of certain species is completely normal and even useful. Anyone who is at least a little familiar with the history of life on Earth understands that modern species of animals did not always live on it: they arose in the process of evolution and someday may disappear. As, for example, this happened with mammoths about ten thousand years ago.

And they are just one of many extinct species. Some species die out without surviving even a couple of million years, while others live on Earth for hundreds of millions. Species leave to make way for others.

In the modern world, humans are primarily responsible for the extinction of species. People hunt, trade rare animals or plants, and destroy their habitat. Every hour three species of plants or animals disappear on the planet; Accordingly, every month the Earth irreversibly loses more than 2,000 species.

What animals were on Earth during the time of dinosaurs?

Apparently, four billion years ago our entire planet was completely covered by ocean. It was here that the first living organisms originated. These were tiny bacteria, green algae and fungi.

And only after many millions of years small fish appeared in the sea. In the Mesozoic era, when dinosaurs already walked on land, the sea still remained more populated, fish of all shapes and sizes frolicked in it: some were as huge as a truck, others had spines growing on their fins, and others were encased in shells. And even then, sharks roamed the ocean.

However, in the Mesozoic era, the land was inhabited by a wide variety of animal species. But she herself looked completely different from how she does now. The five continents familiar to us did not exist, but there was a single giant supercontinent, which scientists called Pangea. Just then, in the Mesozoic, Pangea began to slowly split into two continents: the northern - Gondwana and the southern - Laurasia.

Most of the animals of that era became extinct, but we know of their many descendants. Even before the appearance of dinosaurs, the first beetles and bugs were already crawling on the ground, centipedes reached two meters in length, and dragonflies could boast of wings that were not inferior in size to those of an eagle. Among the few creatures whose appearance has not changed to this day are representatives of the cockroach order, one of the most successful animals in the entire history of life on Earth (this is unlikely to surprise anyone who happened to encounter them in an apartment), because they have existed for more than 300 million years.

Of course, at the beginning of the Mesozoic era, when dinosaurs dominated the planet, nothing foreshadowed that cockroaches would prevail in evolution. A career guidance consultant, if one had existed in those days, would have advised many species to retrain as reptiles, that is, reptiles. After all, it was in front of them at that time that a brilliant future opened up.

Over millions of years, amphibians—that is, those that could live on both land and water—evolved into reptiles, the first vertebrates that no longer needed water. They had a strong skeleton and laid eggs on land. The first of them were relatively small, ate insects and lived in old stumps. But they began to grow quickly.

To get a little idea of ​​what dinosaurs looked like, you can look at a crocodile: the same large mouth, strong chewing muscles, sharp teeth, and a powerful tail. However, crocodiles are not descendants of dinosaurs: both of them descended from the same group of reptiles - archosaurs.

Archosaurs were among the first to try to live on land. Pretty soon there were a few rebels among them, early mammals who began to evolve in a completely different direction. But at that moment no one could have said what this would lead to.

Our knowledge of ancient animals, and especially dinosaurs, comes from professional and amateur scientists who have discovered many remains of extinct organisms over the past 200 years.

Although we are used to talking about dinosaur bones that were dug out of the ground, strictly speaking, these are no longer bones, but stones. But why did animal bones become stones?

The corpses of animals quickly became prey: predators attacked their meat first, then worms and bacteria got to work. Therefore, there was soon nothing left of the soft tissues, be it internal organs, brain or skin.

Even bones and teeth sooner or later begin to decompose in the sun. Although, of course, they are much harder and more durable than other parts of the body, and bacteria will take much longer to destroy them.

But if dinosaur bones fell into the river and ended up under a layer of silt, they were inaccessible to bacteria and thus preserved to this day. Gradually, water began to penetrate into the smallest pores of the bones, filling them with minerals that were formed from salts dissolved in water. Thanks to these substances, over millions of years the bones turned into stones or, as scientists would say, fossils.

Sometimes paleontologists specifically examine the soil in the place where there was a river bed in prehistoric times. After all, this is where you can find dinosaur skeletons.

How do scientists manage to determine with great accuracy how many millions of years old a particular fossil is? It's actually not that difficult. Quite a lot of waste accumulates on Earth: sand dust, lava, plant remains, and animal skeletons. The entire planet's trash settles in layers of sediment.

The deposits of each such layer have their own characteristic features. Let's imagine that hundreds of years later scientists will excavate the site of modern America. At some point, they're bound to start finding lots of Coca-Cola cans and CDs. If there is also a dollar with an engraved date nearby, then we can conclude: if the same Coca-Cola can is found elsewhere on Earth, then the entire layer in which it was found most likely dates back to the 20th century. That is, once they have established the age of a particular layer on any part of the planet, scientists know what time the same layer in any other place on Earth dates back to.

By studying the remains of plants and animals, scientists learn what our planet looked like in prehistoric eras, what the climate was like then: cold or warm, wet or dry, and whether summer and winter were very different from each other. Sometimes they can determine with a high degree of accuracy what the weather was like at one time or another, even if it was millions of years ago. The thing is that both animals and plants are perfectly adapted to their habitat, and their remains can tell us a lot about the nature of that time.

For example, if there are corals in some ancient layer of the earth, then we can say that at the time when the layer was formed, the water was quite warm, because corals can only live in warm water.

So paleontologists have established that there were periods on Earth when the level of carbon dioxide in the air was significantly higher than today. Carbon dioxide is released when burned, and its levels in the atmosphere are now of great concern to environmentalists. Environmentalists fear that carbon emissions from cars and power plants could make the Earth too warm.

But in reality everything is not so simple. Indeed, thanks to paleontologists, we know that in the Cretaceous period the saturation of air with carbon dioxide (carbon dioxide) was higher than in our era. Dinosaurs, by the way, only benefited from this. Since plants need carbon dioxide to grow, ferns, conifers, and cycads (a group of ancient plants that looked like palm trees) reached enormous sizes in those days. And the dinosaurs grew up with them.

Why did dinosaurs become so huge?

The first dinosaurs were relatively small, no larger than a brown bear. Unlike their ancestors, slow amphibians, they could move quite quickly, even the shell with spines did not hinder them much. They owed their mobility primarily to the structure of their body: their paws were located not on the side of the body, but under it (this distinguishes dinosaurs from other reptiles). They walked on their hind legs and were primarily carnivores, feeding on reptiles, amphibians and mammals.

By the time dinosaurs appeared on Earth, mammals had already settled very well on it. Thanks to their coat and ability to maintain a constant body temperature, they were well adapted to the rather cool climate of the next ice age.

But with the beginning of the Mesozoic, the Earth became warmer. At this time, the giant Pangea had already begun to slowly break apart and the warm waters of the ocean rushed into the continent. The ice caps at both poles began to melt, the rains became more frequent, and the temperature crept up. On average during that period it was six degrees warmer than today.

These changes were to the taste of cold-blooded reptiles. After all, the speed of their movement directly depends on the ambient temperature - in the cold they are extremely slow. In addition, with a large amount of solar energy, reptiles no longer need such abundant nutrition as mammals. Those constantly need food to maintain their body temperature; The mammalian body can be compared to a stove, into which firewood must be thrown every now and then so that the fire does not go out.

Of course, this is not the only reason why mammals in the Mesozoic era had to give up the leading place to reptiles, but it was one of the most significant.

Among reptiles, dinosaurs have benefited the most from warming. The number of slow-moving turtles, lizards and crocodiles that walked on four legs did not increase much. At the same time, active bipedal lizards quickly strengthened their positions.

True, their development was also not uniform. For example, the first carnivorous dinosaurs did not have enough food to survive, they devoured each other and eventually almost completely died out. Only those who switched to plant food survived.

To grind food in the stomach, they learned to swallow a couple of stones with food each time, since they did not yet know how to chew. And only some of the last dinosaurs acquired massive teeth to grind tough leaves.

The dinosaurs' necks began to lengthen and grow until these giant lizards could easily reach trees and eat leaves right from them. During the Jurassic period, temperatures throughout the planet increased, vegetation became more lush, which means dinosaurs became more obese.

New species of dinosaurs, such as apatosaurs, brachiosaurs and ultrasaurs, spread throughout the planet. In order not to remain hungry, dinosaurs were forced to eat food for twenty hours a day. If they got hot, they went for a swim. And from time to time they dozed off, basking in the sun.

As for the diversity of species, dinosaurs truly had no equal in this. By 2018, about 1000 genera and about 1200 species are already known. It is believed that the total diversity could reach more than 1500 genera and 2100 species! Scientists have divided these diverse animals into two orders - lizards and ornithischians, differing primarily in the structure of the pelvis.

Thanks to the efforts of paleontologists, a large number of dinosaur eggs were found. They are about the size of a football and quite strong, so the hatchlings had to work hard with their beaks to hatch.

In many nests, many eggs were found lying nearby. This suggested that dinosaurs hatched eggs like birds, and then, like birds, carefully and patiently cared for their offspring. This, by the way, is one of the evidences that dinosaurs were quite advanced creatures.

The larger the size of herbivorous dinosaurs reached, the more interesting they were to their other brothers. Thus, a new group of dinosaurs gradually formed and returned to eating meat. And they became more dangerous than all the dinosaurs that lived before them.

These new predators began hunting herbivorous dinosaurs. The largest and most prominent of them was the Tyrannosaurus rex. Presumably it was comparable in size to a one-story house and weighed no less than an elephant. Tyrannosaurus had a giant skull and a small brain. His front paws were extremely small and, most likely, were hardly used. The situation with the teeth was completely different: curved, with small serrations, and on each one it was possible to impale a whole rabbit.

Reptiles lived not only on land, but also in water and even in the air. Ichthyosaurs, similar to giant dolphins, roamed the sea. Mighty pterosaurs flew through the air - their skin resembled the skin of bats.

How these giant animals learned to fly we can only guess. Perhaps the bravest of them once climbed a tree or a rock and jumped from there like squirrels. Only the lightest or those with feathers on their legs and torso managed to survive. And then they passed on the ability to fly to their descendants.

Millions of years ago, the Earth belonged to ancient giants - dinosaurs. They reigned for a long period and suddenly disappeared in a short period of time by historical standards. What were these animals? Why did dinosaurs become extinct?

Giants of Earth's distant past

The name "dinosaur" translates as "terrible lizard." The honor of giving a name to the found remains of huge prehistoric animals belongs to the English paleontologist Richard Owen.

The ancient giants existed millions of years ago and inhabited the entire Earth, including the territory of modern Antarctica. In those distant times, it was part of a single continent along with India, Africa and Australia and had a warm climate. A most valuable discovery was found here - the remains of a lizard that lived millions of years ago. Why did the dinosaurs, which so densely populated the planet in ancient times, become extinct? What force could destroy all the giants without a trace? This is one of the mysteries of our time.

Beginning the Study of Dinosaurs

The bones of these animals were found back in the ancient world. Then they believed that these were the remains of the great heroes of the Trojan War, left on the battlefield. In medieval Europe there was a different point of view - dinosaur bones were mistaken for the skeletons of giants (the Bible mentions them) who died during the Flood. As for the eastern countries, in accordance with their mythological ideas, they believed that these were the bones of legendary dragons.

This continued until the middle of the 19th century, until scientists made an attempt to classify the gigantic remains found. And scientists from two European countries were the first to do this.

British and French contributions to dinosaur research

English scientists were the first to undertake the hard work of describing and classifying the giants of the prehistoric world. Back in the 17th century, Oxford professor Plott first described the bone of a megalosaurus, which was then mistaken for the remains of a giant who died during the Flood. At the beginning of the 19th century, the outstanding French zoologist Georges Leopold Cuvier made a great contribution to the study of dinosaurs. He was the first to classify the fossil remains as a flying reptile and gave the name pterodactyl. After him, English scientists described a plesiosaur, a mesosaur and an ichthyosaur.

Systematic research and description of the bones of prehistoric animals found by that time began in 1824 in England. Then Megalosaurus, Iguanodon, and Hyleosaurus were described and named. In 1842, Owen noticed their similarities and differences from modern reptiles and identified them as a separate suborder, giving them a common name - dinosaurs.

Now we already know quite a lot about the giants of antiquity, but one of the important questions remains unanswered: “Why did dinosaurs become extinct?”

The time of existence of terrible lizards is the Mesozoic era

Today, the remains of the most ancient dinosaurs date back approximately 230 million years. One of the earliest lizards is the Staurikosaurus.

According to scientists, dinosaurs appeared in the Late Triassic, reigned on Earth during the Jurassic period and suddenly disappeared at the end of the Cretaceous. This happened 65 million years ago. The era of dinosaurs is the Mesozoic. It is characterized as a very interesting time in which many important events took place. First of all, this is the period of dinosaurs, who then reigned on the planet. But it was in the Mesozoic that modern flowering plants, birds and mammals appeared - those that surround us now. In addition, this is a time of enormous changes in the face of the planet. First, in the Triassic period, the giant continent of Pangea split into Laurasia and Gondwana. Then the latter, in turn, split into modern Africa, South America, the Hindustan Peninsula, Australia and Antarctica.

At the end of the Cretaceous period, another important event occurred - the disappearance of the giant owners of the planet. Why did dinosaurs become extinct? This question has not received a definitive answer since then.

The era of dinosaurs - the Mesozoic - is characterized by a warm and mild climate. At that time there were no such temperature changes as there are now. The climate on the entire planet was approximately the same. The fauna was diverse.

Reptiles were widespread, and the first mammals appeared. The heyday of the planet's fauna occurred in the Jurassic and Cretaceous periods. Jurassic dinosaurs are best known to modern man. At this time, huge reptiles appear, represented by a wide variety of species: flying, sea, terrestrial, herbivores and predators.

Types of dinosaurs - from small to large

The famous reptiles of antiquity trace their ancestry to archosaurs. They appeared at the end of the Triassic period and quickly became the leading form of life. Now they are represented by modern crocodiles. Then, millions of years after the Permian mass extinction, dinosaurs diverged from them. There are several hypotheses about where exactly the terrible lizards first appeared. According to one of them, this happened in South America.

During the most famous period of dinosaurs - the Jurassic - these reptiles acquired gigantic proportions. Scientists count a huge number of species of giants of the prehistoric world - more than a thousand. They, in turn, are united into 500 genera and are divided into two groups: lizard and ornithischian. In addition, they can be divided into herbivores (sauropods) and carnivores (theropods), as well as terrestrial, semi-terrestrial, aquatic and flying.

The biggest

Huge dinosaurs are of greatest interest to modern people. Today it is difficult to imagine that giants up to 20 meters high and up to 40 long once roamed the Earth. The largest herbivore dinosaur is the Seismosaurus. Its length reached 40 meters, and its weight was close to 140 tons. Amphicelia is another giant herbivore. It is possible that its length was up to 60 meters. It is impossible to prove this now, since the only vertebra of this reptile was lost.

Predatory dinosaurs were also huge in size. For a long time, the Tyrannosaurus rex was considered the largest and most dangerous of them. According to recent studies, the giant laurels among the predators of the Mesozoic era passed to the Spinosaurus. He is about 18 meters tall, has huge long jaws like a crocodile, and weighs 14 tons - this is his appearance. However, the other predatory dinosaurs were not much inferior to the Spinosaurus and Tyrannosaurus.

Small and dangerous

Among the ancient reptiles there were also individuals of modest size. Compsognathus is the smallest of the carnivorous dinosaurs. It weighed a little more than two kilograms, and the average length of an individual was 100 centimeters. Armed with sharp teeth and three long claws on its front paws, it posed a serious danger to small animals.

Heterodontosaurus is another representative of small dinosaurs. Scientists conventionally classify it as a herbivore, but the presence of fangs suggests that it was more likely an omnivore.

As can be seen from the above, the types of dinosaurs were very diverse.

The Mystery of the Disappearance of Dinosaurs

The mystery of the death of dinosaurs has been of interest not only to scientists for the second century. Today it has been possible to establish the approximate time of their extinction, but one can only guess about its reasons. There are a huge number of hypotheses about what happened. There are some among them that most researchers of the world of dinosaurs agree with, but there are also many completely fantastic assumptions.

First of all, it must be said that similar mass extinctions of species have already happened in the history of our planet. Scientists count five such events, when up to 96% of all life on Earth disappeared.

Around 65-66 million years ago, at the end of the Cretaceous period, an unprecedented extinction of life occurs again. It is most famous for the reason that the dinosaurs that reigned on land and sea disappeared completely. For some reason they were unable to adapt to the changed conditions. What has changed so much and what is the reason for the changes that have occurred? Why did ancient reptiles become extinct, but mammals that already existed in the era of dinosaurs survived and began to reign on the planet?

Possible reasons for the great extinction include:

• the fall of a huge meteorite or asteroid;
• epidemic;
• comet collision;
• increased volcanic activity, which led to the release of ash and a change in the Earth's illumination (drop in temperature);
• a sharp change in the planet’s magnetic field;
• gamma-ray burst;
• extermination of eggs and offspring of pangolins by widespread predatory mammals;
• an experiment carried out on the animal and plant world of the Earth by an alien civilization.

This is only a small part of the versions of the death of dinosaurs. They all have many flaws, and most lack actual evidence. None of these theories can explain the entire complex of events that occurred.

Domestic scientists have put forward a biosphere version of the death of dinosaurs, which convincingly proves how this could have happened. In their opinion, this happened due to two events: climate change and the appearance of flowering plants. A new type of vegetation replaced all old forms.

New insects appeared that fed on flowering plants, which led to the extinction of previous species. Turf appeared, which prevented soil erosion and the leaching of nutrients into the seas and oceans. As a result, they became impoverished, which is why most of the algae died. This led to the extinction of marine life. Further along the food chain, flying lizards, closely associated with bodies of water, began to die out. On land, dinosaurs' competitors were small predatory mammals that destroyed the offspring of giants. Cold weather and the constant struggle for survival further aggravated the plight of the dinosaurs. Under such conditions, they lost their evolutionary advantage. The old species continued to exist for some time, but new ones no longer appeared.

The main disadvantage of the biosphere version is the fact that practically nothing is known about the real physiology of dinosaurs.

Where can you see dinosaurs?

Despite the fact that the terrible lizards disappeared millions of years ago, they can still be seen today. To do this you need to visit the dinosaur museum.

There are paleontological institutions that store the bones of ancient lizards. And in Australia a special dinosaur museum has been opened. Here you can see not only a collection of fossils, but also admire sculptures of lizards in the garden.

There are many different theories of the creation of the world and its development. And they are similar in only one thing: dinosaurs really existed. Moreover, this can be confirmed by a whole range of evidence. However, no one can still say with certainty why dinosaurs became extinct. There are only a number of hypotheses that explain the possible reasons for the extinction of an entire population of these creatures.

Dinosaurs are classified as land vertebrates that lived in the Mesozoic era until the very end of the Cretaceous period. Their ancestors are considered to be reptiles, which are similar in structure to modern lizards. The appearance of dinosaurs on Earth is considered the result of a mutation of reptiles due to climate change.

Based on this and other knowledge about dinosaurs, various hypotheses began to emerge about why they disappeared.

Asteroid impact

This hypothesis is based on the assumption that at the end of the Mesozoic era a huge asteroid fell on Earth. The dust that rose after the fall did not settle for a long time. The sun's rays scattered in it, which led to cold weather and almost complete darkness. The lack of sunlight significantly slowed down or completely stopped processes important for the inhabitants of the planet (for example, photosynthesis).

Most plants and animals became extinct or were rebuilt to new living conditions. And dinosaurs were no exception. A complete restructuring of the entire marine and terrestrial habitat began. This version is confirmed by layers of clay found in all corners of the world, in which platinum elements, including iridium, significantly predominate. This substance is rarely found in the earth's crust, but it is an integral part of meteorites.

Glaciers

One of the reasons for the extinction of dinosaurs is considered to be the onset of the Ice Age. The cooling occurred at the end of the Cretaceous period, but many scientists are inclined to believe that this phenomenon was observed much later. Not a single life form existing at that time was prepared for such drastic climate changes.

There is no clear answer to the question of what influenced the movement of glaciers. And if we compare the chronology of this event with biblical texts, we can assume that instead of glaciers there was a massive flood.

Volcanic activity

This version is rather the reason explaining the onset of the Ice Age and, as a consequence, the extinction of dinosaurs.

It is assumed that at the end of the Cretaceous period, most of the volcanoes on Earth began to show excessive activity. This led to shifts in the earth's crust. Volcanic dust and ash influenced the temperature change. But such a process had to take place not spontaneously, but gradually, so all the giant lizards could not die.

Natural selection

In the modern world, no one is surprised by statements that many species of plants and animals are on the verge of extinction. Everyone understands perfectly well that this is mainly influenced by anthropogenic factors.

However, it can be assumed that the dinosaurs were killed not by climate change, but by a neighboring population. It is only in R. Kipling’s “The Jungle Book” that animals say to each other: “You and I are of the same blood.” In life, the strongest population survives - this is the essence of natural selection.

Epidemic

Based on Charles Darwin's theory of evolution, bacteria and microbes appeared before all other forms of life on Earth. The processes of evolution did not bypass them, and these microorganisms mutated. Thanks to such statements, a new hypothesis was born about why giant lizards became extinct.

Any living organism adapts to changing environmental conditions, but not all inhabitants of the Earth can live with different bacteria on the principles of mutualism (“mutually beneficial cohabitation”). Therefore, the version that the dinosaurs were destroyed by an epidemic has the right to life. It is quite possible that most of the epidemics that at one time destroyed a huge number of people also destroyed the dinosaurs millions of years ago.

The proof of this theory can only be knowledge about some properties of microorganisms. The fact is that bacteria survive under a wide variety of environmental conditions. In severe frosts, they do not die, but simply curl up into a cyst. This shell allows microbes to live for a huge number of years in the so-called sleep mode. As soon as conditions again become suitable for the life of microorganisms, they “wake up” and begin to multiply.

Hunger

One of the most unfounded versions of the death of dinosaurs is considered to be a lack of food. There is a theory that someday there will not be enough resources on the planet for everyone, and this will lead to the end of the world. Although such assumptions are easy to prove through simple calculations, they concern the future.

It can be assumed that dinosaurs survived all climate changes, but the plants they ate did not survive. But this only explains the death of herbivorous mammals. Where then did the lizard-pelvic predators go?

Change in Earth's gravity

One of the most recent versions suggests that giant lizards disappeared due to an increase in the Earth's gravitational force. The theory is based on the fact that planets gradually increase in size. This means that their mass and force of attraction also increase. This circumstance could well have affected the mobility of dinosaurs, as well as other creatures.

To understand why this happens, we can recall an example of such a phenomenon as complete weightlessness in outer space on ships. That is, the lower the force of gravity, the easier it is to move. The weight of the dinosaurs was too high, and their bodies might not actually be able to adapt to such changes. Every day it became harder and harder for them to move, which significantly hampered their search for food and their life processes in general.

Are dinosaurs still alive?

While some scientists are puzzling over the reasons for the disappearance of dinosaurs, others put forward hypotheses that these creatures did not become extinct at all, and find confirmation of this!

Such hypotheses were initially based on the fact that some legends of different peoples were confirmed. And many legends spoke about magical creatures - dragons, which in ancient times people began to destroy. They found their salvation in caves and rocks located very far from human settlements. All descriptions of magical creatures are similar to descriptions of dinosaurs.

At the moment, information is increasingly appearing about chupacabras and other strange creatures living in the mountains, forests and under water. And there is already a lot of evidence of their existence. For example, the monster Nessie, who lives in Loch Ness.

A life form similar to the Loch Ness monster was seen in the Jökulsau au Dal river (Iceland) and in Lake Winderwin (England). Eyewitnesses claim that the monster looks like prehistoric reptiles, it has a huge body and a long neck and fins. The first mention of this creature is in the records of Roman legionnaires, who were at war with the Celts at that time. It is possible that the monster is a direct descendant of dinosaurs.

In 1915, the German submarine I-28 blew up the English steamer Iberia. In the logbook, the sailors noted that the ship sank too quickly and exploded at a depth of 1000 meters. The wreckage of the ship floated to the surface of the water. Among them, the crew saw a strange creature that looked like a crocodile with four flippers.

The length of the sea monster was about 20 meters. Cryptozoologists drew attention to this fact. After a thorough study of the issue, they concluded that, most likely, the monster is none other than a mosasaurus, considered long extinct.

But the most striking evidence that not all dinosaurs died is the tuatara. It is often confused with a common lizard. However, scientists have proven that this is not a descendant of one of the dinosaur species, but a real three-eyed dinosaur.

Dinosaurs are huge lizards, the height of which reached a 5-story building. Their remains are found deep in the earth, which is why scientists say that dinosaurs lived on Earth millions of years ago. The last dinosaurs went extinct about 65 million years ago. And they appeared 225 million years ago. Judging by the remains of the bones of these lizards, scientists conclude that there were more than 1000 varieties of such animals. Among them were large and medium-sized, bipedal and quadrupedal, as well as those that crawled, walked, ran, jumped or flew in the sky.

Why did these giant animals become extinct? There are several theories about their death.

Why dinosaurs became extinct: scientific research facts

Since the death of dinosaurs occurred a very long time ago, we can only build hypotheses based on known scientific facts:

• The extinction of the dinosaurs proceeded very slowly and took millions of years. This period was called “glacial” by paleontologists.
• Over the course of these millions of years, the climate has changed. In the previous era, there were no ice caps on Earth, and the water temperature at the ocean floor was +20ºC. Climate change has caused a decrease in overall temperature and the appearance of significant icing.
• In addition to climate, the composition of the atmosphere changed. If at the beginning of the Cretaceous period the air contained 45% oxygen, then after 250 million years it was only 25%.
• During this period of time, a planetary catastrophe occurred. It is confirmed by the presence of iridium, an element that is located deep in the earth’s core and is also found in asteroids and comets. Iridium is found in deep layers of soil throughout the planet.
• There are indirect witnesses of the collision of the Earth with an asteroid - huge craters. The largest are in Mexico (80 km in diameter) and at the bottom of the Indian Ocean (40 km).
• Along with dinosaurs, some species of lizards (sea and flying) became extinct.

When and how dinosaurs went extinct: theories of disaster

Habitat change

Our planet is changing very slowly but steadily. The climate is changing, new species of animals appear and old species disappear. They find themselves not adapted to life in new conditions.

Cold snap

The average air temperature dropped from 25ºC to +10ºC. The amount of precipitation has decreased. The climate has become colder and drier. Dinosaurs, like other lizards, were not adapted to life in cool conditions.

It is known that most lizards are cold-blooded. When the air temperature drops, they cool down and become numb. However, this theory cannot explain why those reptiles that were warm-blooded and could hibernate became extinct.

Another theory is more viable - as a result of climate change, there is less grass vegetation - ferns, which were eaten by non-predators. Judging by the size of dinosaurs, they needed substantial thickets of food to feed them. As a result of a decrease in the amount of food, gradual extinction began. Herbivores died because they lost food. And the predatory ones - because there were few herbivores (which they ate).

Planetary catastrophe: collision with an asteroid or explosion of a star

Traces of a collision with a celestial body were discovered on the island of Yucatan - a huge crater covered with stones and soil. When the asteroid collided with the earth, a powerful explosion should have occurred, which would have lifted tons of soil, stone and dust into the air. The dense suspension blocked the sun for a long time and caused a cold snap. As a result, not only dinosaurs, but also a number of other reptiles became extinct. This theory is confirmed by the remains of iridium in the soil of the Cretaceous period.

The explosion of a star relatively close to our planet could be the cause of a significant increase in radiation. However, it is not clear why the colossal emissions of radiation left other animals alive. Why dinosaurs became extinct still remains a mystery that haunts the minds of scientists.

Despite many theories, scientists are making computer simulations and reconstructions of what happened many millions of years ago. This is what the film will talk about.