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 as a flying reptile and give 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.
This question has worried scientists for one and a half hundred years, representing one of the greatest mysteries of our planet: why did dinosaurs become extinct? The mystery of the death also interests several generations of observers far from science. At the moment, a whole pantheon of hypotheses has been erected, which in fact are nothing more than myths. Because they cannot stand any criticism. Our job is to push aside the mythology and provide readers with the most realistic reason possible.
Five Great Extinctions
Before directly turning to the events of the end of the Mesozoic, let's look at time on a different scale. In the history of the Earth, there are at least 5 time points where significant extinctions of species of living beings occurred. These are the so-called “great extinctions”: Ordovician-Silurian, Devonian, Permian-Triassic, Triassic-Jurassic and Cretaceous-Paleogene (under consideration). Let's leave the first two for now (due to the lack of sufficiently highly developed organisms, as well as the remoteness) and briefly compare the last three.The Permian-Triassic (the end of the Paleozoic era, about 251 million years ago) is considered the largest, because up to 96% of all species disappeared during it. At the same time, reptiles, already coming to the fore, successfully survive and evolve.
The Triassic-Jurassic extinction (about 199.6 million years ago) was not as large-scale, but killed up to 75% of species. Reptiles easily survive it and continue to develop, including existing dinosaurs. Moreover, the latter become the dominant form of life in the Jurassic period.
Finally, in the Cretaceous-Paleogene (the end of the Mesozoic era, about 66 million years ago), about 75% of all species disappeared. A significant part of land animals, the most developed animals that reigned supreme at that time (primarily dinosaurs and sea lizards) do not survive!
All three extinctions have major differences, but the Cretaceous one stands out unprecedentedly because of this last fact. None of the various species of dinosaurs that inhabit almost all land zones of the planet have adapted to the changed conditions. Has not evolved. Complete disappearance. How could this happen?
Highly adaptable dinosaurs
A separate publication will be devoted to this in detail, but here we outline the general conclusions. There are a number of criteria by which you can make them.Since the Jurassic period, dinosaurs have reigned supreme on land. They not only establish themselves at the top of food chains, but also occupy vast areas of continents. Dinosaurs are spreading throughout the globe, showing phenomenal migration abilities and adaptability to radically new environmental conditions.
The ability of evolutionary transformation of the body is truly amazing. Even the differences between genera that are relatively close (for example, Psittacosaurus and Triceratops) indicate this. Not to mention the sub-orders. Neither mammals nor birds have even come close to undergoing such metamorphoses for many millions of years. The same applies to the variability in the sizes of “terrible lizards”.
The niche of unsuccessful species is quickly occupied by more successful ones. All this indicates the highest adaptability among the most developed creatures of the late Mesozoic. They were the ones who had the greatest chance of surviving a serious disaster. They disperse, change and become fixed.
Highly developed lizards are the central victim of events
The image shows the state of the continents of our planet at the time of the extinction of the dinosaurs. The model was built by American geologist Christopher Scotese.
How were the various organisms affected? Some plants disappear, but this does not affect the general trend of their development. Angiosperms continue to take root on land. No significant damage was caused to insects either. A number of mollusks are dying out, including cephalopod ammonites and belemnites, but fish are only slightly affected. Amphibians, for the most part, safely continue to occupy their ecological niches. Among the birds, the most progressive survive, having already occupied the air at the end of the Cretaceous. Mammals were not significantly affected and have been developing rapidly since the beginning of the Cenozoic, occupying the niche of dinosaurs.
Now let's turn to reptiles: dinosaurs, sauropterygians and mosasaurs - dominant in the seas - are dying out, as well as pterosaurs. However, lizards and other lepidosaurs survive. Along with crocodiles and turtles.
Based on the results of the calculations, a lot of questions arise: why, with the exception of the class of reptiles, do all the most developed animals that came or are coming to the fore in the Mesozoic experience a “cataclysm”? Why do dinosaurs and sauropterygians go extinct, but crocodiles, turtles and lepidosaurs survive? How are egg-laying birds, descended from terrible lizards, saved? None of them can be explained by a catastrophe of planetary proportions. However, we will still consider the proposed causes of extinction.
The fall of one or more asteroids is a legend
Currently one of the most popular hypotheses in the scientific community. The special colorfulness, not least of all, contributes to its spread among the masses. It is assumed that 66 million years ago, an asteroid invaded the Earth from outer space. Upon impact with the surface, it caused atmospheric pollution with dust particles, crustal activity, and possibly major volcanic eruptions. The rising particles saturated the atmosphere so densely that they obscured the Sun for an extended period. The combination of all factors has given rise to dramatic climate change. Presumably, this led to the complete extinction of dinosaurs and a number of other organisms described above.The formalized idea was first expressed by American physicist Luis Alvarez in 1980. In recent years, the Chicxulub crater on the Yucatan Peninsula (Mexico) has been actively promoted as a crash site. Under the influence of criticism, recognizing the inconclusiveness of the theory, supporters also proposed a version of multiple impacts: several asteroids in different parts of the planet with a short time interval.
We will not list all the shortcomings of the hypothesis (starting with the ongoing debate about the correspondence of the time of the fall and the beginning of extinction), because even the key ones will be enough. Let's say the fall really happened.
Parametric refutation
First, let's pay attention to the size of the objects: on the general map, the red arrow points to the circumference of the Chicxulub crater (click to enlarge).
As we can see, on a planetary scale it is an extremely small formation: the area of the Chicxulub crater is about 25,500 square kilometers, and the area of the Earth is about 51,007,2000 square kilometers. For comparison, the area of the island of Madagascar alone is as much as 587,040 square kilometers.
What size was the asteroid itself then? In order to see it on the upper border of the Yucatan Peninsula, you need to use multiple magnification.
Yes, this point in the center of the crater circle is our promoted “giant”. The diameter of the Chicxulub meteorite is only about 10 km, and the diameter of the Earth is 12,742 kilometers. Thus, the diameter of our planet is 1272 times greater than the diameter of this very asteroid! And the mass, accordingly, is many orders of magnitude. What happens if a microscopic grain of sand falls on a person?
The consequences of the fall of such a small cosmic body will not affect the planet in any way. At most, this could cause pollution in a small radius or a tsunami that could drown a small island. The same goes for multiple asteroids, even if they fell in different parts of the globe. No noticeable effect.
Experimental refutation
However, we will not stop there and refute the theory in a completely different way. Have similar bodies fallen in the history of our planet? Yes, repeatedly. One of the latest occurred about 35 million years ago: at least three large meteorites fell simultaneously or with a short time interval.The first of them fell in Siberia and formed the famous Popigai crater, whose diameter is about 100 kilometers. The diameter of the asteroid itself is up to 8 km. These numbers are comparable to Chicxulub's estimates. The crater is shown in the photo below.
At the same time or with a short interval, a second one falls in eastern North America and forms the Chesapeake crater. Its diameter is from 40 to 80 km. It is mostly underwater, so we present a three-dimensional reconstruction. 
Finally, the third fell in Toms Canyon, near the present city of Atlantic City (New Jersey, USA). The diameter of its crater is about 20 km.
What is the result? No global reactions at this time point. Despite such a massive bombardment (there are signs that there were many more than three meteorites), no cataclysms or mass extinctions occurred 35 million years ago. Which pushes back the asteroid version again.
In general, it is worth noting that, with the exception of Chicxulub, none of the craters with a diameter of over 40 km were formed in close proximity to the marks of the great extinctions. Meteors of small size and mass (relative to the planet) have fallen, are falling and will continue to fall without causing significant damage. There was no collision with a truly giant asteroid, which could have led to an orbital shift and incredible crustal fractures at the end of the Cretaceous period. And, even if this happened, the cataclysm would completely destroy most forms of life (if not all along with the atmosphere). Let's move on.
Active volcanism is a myth
The essence of the theory is an increase in volcanic activity at the end of the Cretaceous in certain points of the planet. The so-called Deccan Traps (India) appear especially often in the literature: a plateau covered with basalt covers up to 2000 meters thick, which were formed from 60 to 68 million years ago as a result of a series of prolonged eruptions. Presumably, a significant release of gases and ash affected the atmosphere. Climatic conditions have changed towards cooling.This hypothesis as the cause of the extinction of highly developed reptiles is being rejected even faster. Firstly, the process described would be protracted, which would allow dinosaurs to easily adapt to changing conditions, as crocodiles or lizards did. Secondly, one or more small volcanic zones could not significantly affect the atmosphere of an entire planet (going back to asteroids). In order to refute this theory from a completely different angle, let’s turn to the weather.
Cold snap and other climate changes - a statue without a pedestal
Global climate changes could only be consequences of other influences, the presence of which is refuted in this work.However, we, of course, will not stop there and will separately present data from climate studies at the point of extinction. First, let's turn to atmospheric temperature, which, as stated, would certainly be affected by a catastrophe on a global scale with an abundance of emissions and other derivatives.
Based on careful analysis, the graph by Christopher Scotese and colleagues shows that there were no climatic jumps at the Cretaceous-Paleogene boundary (labeled K/T in the figure, click to enlarge). There are not even small changes. This further illustrates the fact that no long-term impacts similar to superglobal volcanism occurred. Serious cooling began many millions of years later, at the end of the Eocene. Note also that the Jurassic-Cretaceous boundary is marked by a cooling of 10 degrees, which dinosaurs easily survived.
Let us now turn to an alternative compilation by another scientist, Nasif Nakhle. In addition to verified temperature estimates, it shows a graph of changes in atmospheric carbon dioxide (purple). It is traditionally a sign of active volcanism, and also reflects other complex processes on the Earth's surface. 
As we can see, no sharp jumps or transitions are observed at the time of the Cretaceous-Paleogene event. From approximately the beginning of the Cretaceous period, carbon dioxide concentrations gradually decreased and did not have a significant effect on animals. In addition, this refutes the existence of factors directly related to this gas. By the end of the Cretaceous, the concentrations were approximately similar to those in the mid-Jurassic.
Food shortages or mass poisonings are an illusion
There are unfounded speculations that herbivorous dinosaurs might not have had enough food at the end of the Cretaceous, which led to their death. Predatory dinosaurs are deprived of their prey and die as a result. A more elegant version talks about the poisoning of herbivorous dinosaurs by flowering representatives of the flora, many of which contained alkaloids. It is believed that these substances were poisonous to ancient reptiles. Accordingly, predators suffer the same fate.In fact, dinosaurs had an incredibly varied diet. There was no rigid dinosaur-dinosaur food chain: for example, small theropods hunted mammals, lizards and insects, while ornithopods feasted on pine needles, roots and mushrooms. Thus, the lack of food for some did not affect others. Taking into account, in addition, the territorial distribution.
As for alkaloids, dinosaurs eagerly consumed flowering plants for many millions of years, and this only had a positive effect on digestion.
Viral or bacterial epidemic is a fiction
As stated above, dinosaurs and other advanced reptiles were so diverse that they could not have been infected by one type of virus or bacteria. In addition, due to the zonality of any epidemic of non-intelligent animals, the natural transfer and spread of the disease throughout the planet was impossible.Supernova explosion - a fairy tale
It is based on the explosion of a supernova at a relatively short distance from the solar system. The emission of particles could reach the Earth and affect inhabiting creatures. However, there is no evidence that the planet was subjected to massive radiation during that time period. But even if this happened, it would affect all animals without exception. Moreover, genetically, crocodiles or birds are located not far from dinosaurs.Mammals or other factors caused irreparable damage to egg laying - fable
The version has nothing to do with reality, because the lizards were very diverse. The laying of eggs, depending on the species, was located in special places: from small depressions to sky-high rocks.However, most dinosaurs were very fertile. The loss of some eggs was provided for by nature and did not affect the population. The eggs of some dinosaurs were eaten by other genera from the moment of their origin, and this did not in any way affect the overall development.
Let us add that lizards, crocodiles, and turtles also lay eggs, but survive safely. And some extinct animal species did not lay them at all. The combination of these factors does not provide any basis for this statement.
Falling sea levels are a fiction
If marine animals could have suffered in some way as a result, then this does not explain the disappearance of land reptiles throughout the globe.Now let's move on to a more original version.
The coincidence of several natural factors is the sum of zeros
Some scientists suggest that several of the above events took place at once. Their combination led to such catastrophic consequences. One of the main proponents of this trend for many years has been Princeton University professor Hertha Keller. She believes that at the height of the Indian volcanic eruptions (Deccan Traps), at least two large meteorites fell.According to her model, the first, previously mentioned Chicxulub, fell 300,000 years before the Cretaceous-Paleogene boundary and could not be the cause of the extinction of dinosaurs. At the extinction point, a collision occurred with a second asteroid, approximately 2 times larger. According to her calculations, he should have left a crater 250-300 km in diameter. It was this object that led to a large-scale anomaly of rare earth metals (which will be discussed in detail later). Several other much smaller meteorites could have fallen at the same time.
By coincidence, this coincided with the most intense phase of Indian eruptions, and in total led to a sharp jump in climate. The combination of these factors was the cause of such mass extinctions. Moreover, it is important to note that Hertha Keller attributes the leading role to the “Deccan Volcanic Outburst”.
Now let's begin to refute this hypothesis. As we showed earlier, all the impacts cited by Keller either did not take place at all, or did not go beyond the usual framework, or were exclusively local in nature. The sum of insignificant events at individual points on the planet could not lead to a catastrophe on a planetary scale, even with an incredible coincidence in time.
Separately, let’s say a few words about the asteroid component. We agree that the Chicxulub crater most likely formed before the extinction and could not have been its cause. At the same time, the second asteroid proposed by Hertha Keller did not exist at all. To date, there are no suitable craters with a diameter of 250 km at this time point. As an interesting addition, we offer one of Hertha Keller's compilations (click to enlarge).
On the right is a geochronological scale with the percentage of extinct organisms. Known craters are placed in the center, sorted by diameter. The supposed Keller crater is marked in black. On the left side there are periods of increased volcanic activity.
Although this is only current data, it can already be noted that there is no direct connection between volcanism, asteroids and mass extinctions.
Paleocene dinosaurs or survivors of the cataclysm - wishful thinking
There are still suggestions that some dinosaurs and other extinct animals could actually have safely survived the events at the Cretaceous-Paleogene boundary. According to this version, their extinction occurred tens or even hundreds of thousands of years later, already in the deep early Cenozoic.One of its main defenders is the American geologist James Fassett. He devoted a considerable part of his time to the study of North American geological formations. As evidence to date, Fassett cites a number of fossils of duck-billed dinosaurs that were discovered in the lower Paleocene layers of the Ojo Alamo Formation (New Mexico, USA). Among them there are predominantly single bones.
Similar finds have also been made by other paleontologists in the Hell Creek Formation (USA). According to the authors, they were located in rocks formed 40,000 years later than the Cretaceous-Paleogene boundary.
The main argument of James Fassett is a set of 34 bones from the same Ojo Alamo, which by all indications belong to an individual hadrosaurid. According to him, they were found in rocks formed several hundred thousand years later than the Cretaceous-Paleogene boundary. Here is a photo of these fossils from the excavation site. Below, the discovered skeletal details are highlighted in black.
In fact, no Paleocene dinosaurs existed. No species survived the Cretaceous-Paleocene event. Finding objects in overlying rocks is quite common for our living planet. Both the single fossils and this small assemblage of hadrosaurids ended up in higher strata as a result of erosion and other destructive geological processes. These may include rivers, winds, earthquakes, landslides and a huge number of other natural factors.
For example, a stormy river could tear a piece of rock from the shore and wash its contents in another place, not necessarily distant. Thus, the fossil ends up in another geological niche, where millions of years later it is recovered by paleontologists. This can be called natural reburial of fossils.
A group of scientists who examined this formation in detail in their work completely agrees with this argument "No definitive evidence of paleocene dinosaurs in the San Juan Basin". In general, Ojo Alamo is a mixture of many rocks, which may be the result of local disasters. It is by no means a sufficient basis for research.
In addition, in relation to it, Fassett has an incorrect dating (Naashoibito block), which is also mentioned in the publication: those rocks that are shown as Paleocene actually belong to the late Maastrichtian.
Evidence of surviving dinosaurs requires showing large burials with nearly complete skeletons in various formations around the world. Nothing of the sort happened.
The answer is the theory of controlled evolution.
So, options for natural disasters do not stand up to criticism. What are the true reasons for the extinction of dinosaurs?Having studied the issue for a long time, we propose a version that fully explains the death of the dinosaurs: our planet has been an experimental site for another intelligence for a long time. 66 million years ago, as part of a long evolutionary experiment, dinosaurs and other highly developed dinosaurs were destroyed.
We called the source of influence the directing mind (NR). It is likely that all or part of the other great extinctions were also initiated by the latter.
Purpose of the experiment
It consists of two parts. Firstly, HP has been studying evolutionary processes as part of scientific research for a long time. The research results then receive practical application outside our planet.In parallel, the “earth experiment” is a game and at the same time a film, which can be watched for an unusually long time. If people play computer strategies, then HP manipulates living beings. If humanity watches films, the plot of which cannot be influenced, then full interactivity is available to HP.
Intervention in natural processes occurs periodically when course correction is required. Periods of non-intervention can last for tens of millions of years, as long as everything goes according to the established plan.
Why dinosaurs?
Everything is very simple. As part of the experiment, highly developed lizards ceased to be necessary, while they did not provide significant maneuver to other species. There were no natural evolutionary turns. They dominated on land and in water, not giving them the opportunity to turn around. Without extermination they would have continued to dominate for many eras after.In addition to a number of indirect ones, the main task was to free up the niche of dinosaurs for mammals, which at that moment were of greatest interest to the NR. This class of creatures led a secretive existence under the heel of lizards for many millions of years. It was necessary to free the sea-land first for the push of mammals.
What about belemnites?
You may ask, why did a number of other organisms disappear? The answer is also simple: dinosaurs were the primary, but by no means the only goal. A whole list of animals was completely destroyed.In particular, the so-called lagging or dead-end species, according to HP, die in order to free up more space and food for the advanced ones. For example, hesperorniformes and similar toothed birds are destroyed. They got along well with the ancestors of modern birds and could survive for millions of years. The absence of ammonites and belemnites gives more space to those remaining in the seas.
As a result of the operation, a sudden disruption of the food chain could lead to additional extinction of some unaffected genera, but on a significantly smaller scale. Within the limits allowed by the plan.
The essence of HP and the method of destruction
The incredibly low moral level is striking: for the sake of mercantile goals, huge populations are being swept away. They are nothing more than inanimate objects in the hands of a manipulator. Complete disregard for the life of living beings, reflecting composure and special ruthlessness.Despite the significant difference with us in the period of existence and accumulated knowledge, HP is by no means omnipotent. The mechanism of evolution is not subject to it, otherwise the very fact of control would not be required. He guides, but cannot predict details and look far ahead.
The operation was performed in a very short period of time. Most likely, from one to several days. Firstly, the long stay of the equipment on the planet and its repeated use could lead to undesirable consequences for many species not included in the blacklist. Undesirable factor of randomness. Secondly, the animal placement scheme was drawn up and delays could lead to migrations or even intraspecific changes. And these are unnecessary actions and departure from the plan, which is not typical for HP.
Since the level of technology is many orders of magnitude higher than human technology, we can only guess about the details. And ways to destroy dinosaurs.
Iridium - the key to information?
However, of particular interest are the layers of iridium that are found literally all over the world. High concentrations occur at the end of the Mesozoic era.The metal is incredibly rare in natural deposits, suggesting an unearthly origin. It is very likely that these are the results of emissions from HP devices or a by-product of the weapons used during the operation. Confirmation of the theory of controlled evolution. The photo below shows an inch layer of iridium 16 km from the town of Trinidad (US state of Colorado).
The following photograph shows a section of rock from the San Diego Museum of Natural History (USA), a visually noticeable line of which contains an iridium concentration tens of times higher than normal. It was found in Wyoming.
What are the properties of the phenomenon that affected our planet at the Cretaceous boundary? Maps of iridium anomalies will be very revealing. We present to your attention an illustration from the scientific work of Phillip Kleiss, Wolfgang Kiessling and Walter Alvarez (2002).
Here: double white circle - the vicinity of Chicxulub; white circles – an anomaly is present, but concentrations are unknown; the rest are areas with an iridium anomaly. The size of these reflects the concentration (1 ppb is 0.0000001% of the material).
In total, this is about 30% of the potential zones, but it is already clear here that the points are distributed throughout the planet. About 55% are still being studied. This does not take into account the fact that new ones arise periodically.
Currently, the largest number of points are located in North American and Eurasian territories. This is primarily due to the fact that the main paleontological and geological research is carried out mainly in technically equipped countries with a traditionally strong scientific base. Or next to them. Accordingly, work is carried out very rarely in the oceans. The second reason is the level of accessibility of the Late Maastrichtian layers.
Another strike on asteroids
It has been noted that the supposed foreign origin of iridium microparticles is one of the arguments of supporters of the asteroid version. In fact, the current base proves the opposite. Points of various concentrations are scattered throughout the map, and have no direct connection with the supposed epicenter - Chicxulub.Attempts to explain the spread of the anomaly by incredible sea currents dragging dust masses across the entire Earth, or by phenomenal air currents, come up against real facts: many thousands of kilometers from Chicxulub, concentrations comparable to nearby ones are found. At the same time, about 15% of the studied points on the M/P boundary do not contain signs of an anomaly at all (only half as many do contain them). No uniform distribution. Moreover, some of the latter are located a short distance from those where the signs are present.
Apparently, there was not complete coverage of the planet, but a certain zonation. We have an assumption that it may well be connected with the habitat of exterminated NR species.
There is also no evidence of a massive fall of asteroids: in particular, there are no craters similar to Chicxulub in the well-studied European zone, where considerable clusters are visible. This is what the complete map from the same work looks like.
Black triangles are places of potential anomalies, circles are places with recorded signs, squares are places without recorded signs.
Another blow to volcanism
Iridium concentrations at the M/P boundary are significantly higher than the statistical average. Although there have been plenty of time periods with active volcanism in the history of the planet, analogues of such a global anomaly outside the points of great extinctions have not been recorded. In particular, neither in the Jurassic-Cretaceous interval, nor in the 66 million years following the extinction. This refutes the theory of catastrophic volcanism at the end of the Mesozoic.Thus, 66 million years ago, some areas of the planet were strewn with microparticles, while others were free. There is virtually no doubt that this picture is associated with the Cretaceous-Paleogene extinction. The only question is whether this is a direct component of the HP weapon or only a consequence of its use.
Hopefully further excavations and fossil studies will provide more details.
Three milestones
In addition to the extinction of dinosaurs, there are two more great mysteries in the history of the Earth - the origin of life and the emergence of intelligence. Unexplained by known hypotheses, they fit perfectly into the theory of controlled evolution, creating a complete picture of the manipulation of life over hundreds of millions of years. But about them in detail in the following publications.As it cooled, it condensed into trillions of glass droplets a quarter of a millimeter in diameter. They rushed to the surface of the Earth with enormous speed and heated the upper layers of the atmosphere so much in some places that fires broke out on the ground. “The intense heat from the re-entering ejecta created a heat effect on the planet,” Johnson says. “Now you have a stove.”
Soot from the fires, combined with dust from the impact, blocked the light of the Sun's rays and plunged the Earth into a long, dark, wintry darkness.
Over the next few months, tiny particles fell to the surface, obscuring the entire planet in a layer of asteroid dust. Nowadays, paleontologists can see this layer preserved in the fossil record. This is the Cretaceous-Paleogene boundary, a turning point in the history of our planet.
In 2015, Johnson walked 200 kilometers of exposed Cretaceous-Paleogene strata in North Dakota in search of fossils. “If you look underneath the layer, you can see dinosaurs,” he says. “But if you look higher, there are no dinosaurs.” 
In North America, before the Chicxulub impact, fossils paint a picture of lush forests with rivers flowing between them and a dense undergrowth of ferns, aquatic plants and flowering shrubs.
Then the climate was warmer than now. There were no ice caps at the poles, and some dinosaurs roamed the northern lands of Alaska and far south in the Seymour Islands of Antarctica.
“The world was as biologically rich and diverse as anything we see around us today,” Durda says. - But subsequently, and especially near the crash site, the environment became similar to the lunar one. Deserted and barren."
Scientists deduced the consequences of the asteroid fall by studying the Cretaceous-Paleogene layer, which was found in 300 places around the world. 
“Unlike any other geological process, an asteroid impact occurs instantly. All this did not extend over hundreds or tens of millions of years. It all happened instantly,” Johnson says. “Once we have identified the debris layer in the asteroid’s impact crater, we can go lower and higher and compare what happened before and after.”
Closer to the impact site, animals and plants died either from scorching temperatures, wild winds, earthquakes, tsunamis or boulders falling from the sky. Further, even on the other side of the globe, species suffered from a chain reaction such as lack of sunlight.
In regions where wildlife was not destroyed by fires, temperatures destroyed food for animals and acid rain spoiled water supplies. To make matters worse, the debris in the air caused the surface of the Earth to become as dark as an unlit cave, putting an end to photosynthesis and destroying food chains.
As the vegetation disappeared, the herbivores had nothing to eat. If the herbivores die, there is nothing left for the carnivores to eat. It became impossible to survive. Everything that was not burned died of starvation. 
Fossils show that nothing larger than the raccoon survived. Small creatures have a chance because there are usually more of them, they eat less and can reproduce and adapt faster.
Freshwater ecosystems, in principle, fared better than land ones. But in the ocean everything went to pieces, all food chains collapsed.
While the long winter stopped photosynthesis, its impact was greater in the hemisphere that was entering the growing season. “If you're in early summer in the northern hemisphere, for example, and you have your lights turned off during the growing season, there are problems.”
Fossils indicate that North America and Europe were the best after this hell. This suggests that winter was beginning in the northern hemisphere when the asteroid fell.
But even in the worst-hit areas, life soon began to creep back.
“Mass extinction is a double-edged sword. At one end: what killed the life. At the second end: what abilities did plants and animals need to survive, develop and recover?
Recovery took a long time. It took hundreds, if not thousands of years to restore ecosystems. Scientists estimate that it took three million years for organic material in the oceans to return to normal.
Just like after a forest fire today, ferns quickly colonized the burned areas. In ecosystems that escaped the invasion of ferns, thickets of algae and mosses predominated.
In areas that escaped the worst of the devastation, some species survived to repopulate the planet. Sharks, crocodiles and some species of fish survived in the oceans.
The extinction of the dinosaurs meant that new ecological niches were opened up. “It was the migration of mammalian species into these empty ecological niches that led to the abundance of mammals that we see in the modern world,” Durda says. 
When scientists drill into the crater this spring, they will again try to get a clearer picture of how the crater formed and the consequences of the fall for the climate.
"We'll be able to do better analysis from inside the crater," Johnson says. “We are learning a lot about the distribution of energy and especially about what happens to the Earth when something of this size falls on it.”
Scientists will also look at minerals and cracks in the rocks and try to understand what might have lived there. Drilling will help us understand how life was restored.
“By watching life come back, we can find answers to a couple of questions,” says Galik. - Who returned first? What kind was this? When did evolutionary diversity appear and how quickly?
Although many species and individual organisms perished, other forms of life began to thrive in their absence. This dual picture of disaster and opportunity has been repeated many times throughout the history of the Earth's falls.
In particular, it is likely that if the asteroid had not hit the Earth 66 million years ago, the course of evolution would have been completely different - and humans might not have appeared. "Sometimes I say that the Chicxulub crater was the crucible of human evolution," Kring says. 
He also suggested that large asteroid impacts could have helped life originate.
When the asteroid fell, the intense heat caused intense hydrothermal activity in the Chicxulub crater that could last for 100,000 years.
And it could have allowed thermophiles and hyperthermophiles - exotic single-celled organisms that thrive in hot, chemically enriched environments - to establish themselves inside the crater. Drilling will test this idea.
Since its birth it has been regularly bombed. In 2000, Kring suggested that these impacts created underground hydrothermal systems like those that may have formed in the Chicxulub crater.
These hot, chemically rich, humid places may have given rise to the first forms of life. If this is true, then heat-tolerant hyperthermophiles were the first forms of life on Earth.
Why did dinosaurs become extinct?
Dinosaurs, which conveniently went extinct about 65 million years ago, were eerie creatures - thick-skinned, armored, all teeth and claws. For example, Tyrannosaurus rex, the largest land predator of all time, could easily bite a rhinoceros or an elephant in half with one subtle movement of its terrible jaws. And the weight of herbivorous lizards with columnar legs reached 30 and even 50 tons. And it is no coincidence that paleontologists, having unearthed the heavy bones of another antediluvian reptile, called it a seismosaur, that is, a lizard that shakes the earth. The length of this monster, according to cautious estimates by scientists, was 48–50 meters.
For nearly two hundred million years, magnificent reptiles were the absolute masters of all three elements: agile ichthyosaurs, reminiscent of modern dolphins, swam in the primeval seas, multi-ton diplodocus walked the earth, and toothy pterodactyls looked out for prey in the sky. (By the way, the wingspan of these flying monsters could sometimes reach 16 meters, which is quite comparable to the dimensions of a modern combat fighter.)
Tyrannosaurus rex skull
And then suddenly the giant lizards began to rapidly die out, they were replaced by inconspicuous, small and unremarkable creatures leading a predominantly nocturnal lifestyle. Scientists already knew about sudden and catastrophic changes in the composition of the planetary biota at the end of the Cretaceous period in the 18th century, and since then this mysterious phenomenon has often been called the “Great Dying.”
What happened? Usually textbooks paint such a simple picture. A large and prosperous group of reptiles (both predatory and herbivorous), which populated all the ecological niches of the planet, suddenly and unexpectedly died - instantly and everywhere. And since these giants had no serious competitors at that time (mammals huddled on the margins of evolution and subsequently simply occupied an empty house), it is logical to look for some external reason. For example, a climate cataclysm (sharp cooling or, conversely, warming), a supernova explosion, accompanied by deadly fluctuations in the gamma-ray background, or a change in the magnetic poles, which temporarily deprived the planet of its protective shell.
For some time now, the asteroid hypothesis has become very popular. Allegedly, at the end of the Cretaceous period, a huge meteorite crashed onto the Earth, throwing billions of tons of dust into the stratosphere, which screened the surface of the planet, which led to the death of green plants, and after them, the rest of the fauna. In addition, the fall of such a meteorite could provoke a revival of terrestrial volcanism, which significantly aggravated the situation. It should be noted that serious paleontologists do not particularly support this point of view.
Where did the asteroid hypothesis come from? In the mid-1960s, in geological deposits dating back to the Cretaceous-Cenozoic period (approximately 67 million years ago), scientists discovered a layer of blue clay with an abnormally high content of the rare metal iridium (20 times more than the average in the earth's crust). Subsequently, many similar anomalies were found (in some of them the iridium concentration was 120 times higher than the background), and all of them turned out to be the same age - they lay on the Cretaceous-Cenozoic boundary.
Since there is very little iridium in the earth’s crust, and it is found in abundance in meteorite matter (primarily in iron meteorites, which are considered fragments of planetary cores), the American physicist Alvarez associated the iridium anomaly with the fall of an asteroid. He estimated its diameter at 10–12 kilometers and even indicated the location of the disaster - the Yucatan Peninsula, where he managed to find an impressive crater about 150 kilometers in diameter.
The fall of such an asteroid would greatly shake our planet: a tsunami wave of monstrous force and height would devastate the coasts tens and hundreds of kilometers inland, and a huge dust cloud would eclipse the sun for a long time. A six-month absence of sunlight would destroy green plants (photosynthesis processes would stop), and then (along the food chain) animals - both land and sea.
Since Alvarez put forward his impact hypothesis in 1980. impact- “blow”), a lot of time has passed. Today, several dozen iridium anomalies are known, and in geological deposits of very different ages, but it has not been possible to connect them with the mass death of flora and fauna. Moreover, geologists have at their disposal a number of craters much more impressive than the notorious Yucatan. The diameter of some of them reaches 300 kilometers, but nothing serious has happened to the planetary biota (and this has been reliably established). Which is quite natural, since the biosphere is by no means a children’s construction set, the elements of which can be shuffled and folded at random, but a stable homeostat that can effectively withstand various kinds of disturbances.
The famous Russian paleontologist K. Yu. Eskov notes:
In this sense, the situation with the Eltanin asteroid (about 4 km in diameter), which fell in the late Pliocene, about 2.5 million years ago, on the shelf between South America and Antarctica, is very indicative; the remains of an asteroid were recently recovered from a crater formed on the seafloor. The consequences of this fall look quite catastrophic: kilometer-long tsunamis threw marine fauna inland; It was then that very strange burials of fauna with a mixture of marine and land forms appeared on the Andean coast, and purely marine diatoms suddenly appeared in the Antarctic lakes. As for the distant, evolutionarily significant consequences, they simply did not exist (traces of this impact are contained within one stratigraphic zone), i.e., absolutely no extinctions followed all these terrible perturbations.
Thus, the picture that emerges is quite interesting. As soon as iridium anomalies began to be purposefully searched for, it immediately became clear that their strict connection with the mass death of dinosaurs (or any other organisms) was nothing more than an illusion. The fossil remains of Mesozoic dinosaurs clearly indicate that the catastrophic Cretaceous-Paleogene extinction scenario is no good, since some groups of dinosaurs disappeared long before the iridium anomaly, while others sank into oblivion much later. The process lasted for hundreds of thousands and millions of years, so there can be no talk of any rapidity.
Therefore, the asteroid hypothesis, as well as all other “impact” scenarios, can be archived with peace of mind, since they assume the immediate destruction of flora and fauna. Meanwhile, even the mass death of marine organisms at the end of the Cretaceous period (much more rapid than the extinction of dinosaurs) was instantaneous only by geological standards and lasted for a considerable period - according to various estimates, from 10 to 100 thousand years. As for reptiles, they did not become extinct overnight.
K. Yu. Eskov writes:
How so?! It’s very simple: the extinction of dinosaurs continued throughout the Late Cretaceous at a more or less constant rate, but starting from a certain point this decline ceased to be compensated by the emergence of new species; old species die out - and new ones do not appear to replace them, and so on until the complete destruction of the group. (An analogy: a country is losing a war not because the enemy began to inflict unprecedentedly high losses on it at the front, but for another reason - in the rear, tank and aircraft factories stopped due to lack of raw materials.) In other words, at the end of the Cretaceous there was no catastrophic extinction dinosaurs, but the failure of new ones to replace them (this, you see, noticeably changes the picture). This means that we can talk about a rather long natural process.
Alternative versions are no more convincing - for example, the hypothesis of a sudden change of magnetic poles or a supernova explosion near the solar system. Of course, magnetic polarity reversal is a very unpleasant thing, since streams of charged high-energy particles flying from the Sun are deflected in the magnetic field lines, forming onion scales of radiation belts. If our planet’s thick magnetic “coat” is torn off, then hard radiation will begin to freely reach the Earth’s surface.
But, firstly, the leapfrog of the magnetic poles is by no means an exotic, but a natural periodic process, and data from special studies, as a rule, do not reveal a relationship between global biosphere crises and changes in terrestrial magnetism. And secondly, the biosphere as a whole is a flawlessly adjusted homeostat that easily resists any outside interference.
A supernova explosion is a cataclysm on a galactic scale. If such an event occurs in the vicinity of the solar system (according to astronomers, this happens once every 50–100 million years), then the streams of X-ray and gamma radiation will not only destroy the ozone layer, but will also sweep away part of the earth’s atmosphere, provoking the so-called “effect highlands,” which not all organisms can survive. However, even in this case, extinction will most likely not be sudden, but will stretch over tens and hundreds of millennia. In addition, hard radiation and the effect of high altitudes should primarily affect the population of land and shallow waters, but in reality, as we know, the situation was exactly the opposite: the flora and fauna of the open sea, including microscopic ones, suffered the most, and of the inhabitants of land For some reason, only dinosaurs became victims of the Great Dying.
This amazing selectivity is generally the most vulnerable point of all impact hypotheses: indeed, why did dinosaurs become extinct, but crocodiles survived and lived safely to this day? Perhaps the unprecedented popularity of various kinds of “impact” versions is mainly due to the successes of observational astronomy over the past 20–30 years.
Since we are busy debunking idle myths, it is necessary to say a few words about the fauna of the Mesozoic. In almost any textbook you can read that the Mesozoic era was the era of dinosaurs, and the Cenozoic is the age of mammals that replaced them. Meanwhile, this is a typical scientific prejudice.
Few people know that mammals were contemporaries of dinosaurs (they appeared on Earth almost simultaneously - at the end of the Triassic) and happily coexisted with them for 120 million years. Moreover, if you sort through the fossil remains of all Mesozoic creatures, you will find that the number of mammal species significantly exceeded the number of dinosaur species. True, our distant ancestors, who vaguely resembled South American opossums, were at that time small and timid creatures, leading a predominantly nocturnal lifestyle.
With certain reservations, the term “Great Extinction” itself can be called a pseudo-scientific myth. And if we are talking about scale, then the Permian-Triassic extinction should be called great - a grandiose biosphere cataclysm that happened at the turn of the Paleozoic and Mesozoic. It was generally the largest in the history of our planet: if at the end of the Cretaceous about a quarter of families disappeared into oblivion, then during the Permian-Triassic extinction, 50% of families, 70% of genera and 90% of species disappeared from the face of the Earth. In addition, all marine ecosystems have changed radically. It would be worth noting that all attempts to link the Late Permian crisis with the asteroid impact ended in absolute failure - no traces of the impact impact could be found in the corresponding horizons.
So what caused the extinction of the dinosaurs? One of two things: either climatic changes at the boundary of the Cretaceous and Cenozoic, or purely “natural” reasons - a radical restructuring within ecosystems and a change in communities.
Let's figure it out in order. We are accustomed to the fact that the planetary climate is characterized by pronounced latitudinal zonality: tropical rainforests grow on the equator, to the south and north of them lie savannas, periodically moistened, where countless herds of ungulates graze, and even further to the north and south there is a strip of sun-scorched deserts and semi-desert. The subtropics give way to temperate forests - deciduous and coniferous, and they gradually give way to the cold tundra, where almost nothing grows. Well, at the poles there is eternal frost and eternal ice.
But it was not always so. The Mesozoic is a classic example of a thermal era, when there was no latitudinal zonation, and the global climate resembled the current subtropical Mediterranean type. In the high latitudes and even at the pole it was warm and quite comfortable, but at the same time it was not too hot at the equator. In short, the temperature gradient - both seasonal and daily - was barely perceptible. But at the end of the Cretaceous, the thermoera was replaced by a cryoera with latitudinal temperature differences.
Dinosaurs were cold-blooded (poikilothermic) animals. Not being able to regulate their body temperature “from the inside,” they were entirely dependent on their environment, but in the even climate of the Mesozoic, this did not cause them much trouble. If the outside heat comes in in abundance, and the impressive dimensions do not allow it to cool down overnight (most dinosaurs were large creatures), then maintaining a high body temperature will not be difficult. And all this without any participation of their own metabolism, on which mammals spend 90% of the energy they consume through food.
This curious phenomenon was called inertial homeothermy (warm-bloodedness), and many scientists believe that thanks to this valuable quality, dinosaurs became the rulers of the Mesozoic. And when the climate changed radically at the end of the Cretaceous, the giant lizards disappeared.
It would seem that we have found the answer, but again something doesn’t add up. Why did dinosaurs become extinct, while other reptiles - also cold-blooded - continue to exist to this day? Why did the Cretaceous crisis affect mainly marine inhabitants, while land creatures survived it calmly? Why did some groups of dinosaurs begin to actively die out long before the fateful calendar date, while others slowly lived out their lives in the Paleogene?
Perhaps it makes sense to look for the answer elsewhere - in the structure of ecosystems? Let us remind the reader about the inconspicuous Mesozoic mammals, which lived side by side with lizards for 120 million years, without interfering with them in any way. These small insectivorous creatures, similar to modern opossums or hedgehogs, occupied their own ecological niche, which no one encroached on. But in the Cretaceous period the situation changed radically.
K. Yu. Eskov describes these events as follows: evolution spurred the sluggish metabolism of primitive mammals and created a “phytophage in a small size class” on this new metabolic basis. (Herbivorous dinosaurs were very large animals.) And if a small phytophage appeared, then a predator would certainly arise, which would not limit itself to hunting close relatives, but would grab everyone within its power. Therefore, a baby dinosaur - a small, defenseless lizard that does not have inertial homeothermy - will instantly become a tasty prey for such a 24-hour active predator.
The version is undoubtedly interesting, but it does not answer all the tricky questions. And here genetics, understood in the broad sense of the word, will come to our aid. Let's talk about marginality as the antipode of narrow specialization, because this is how the organic world develops.
Let us once again remember the Mesozoic mammals, who voluntarily gave up the world to magnificent reptiles and vegetated on the sidelines of evolution. Huddled in remote corners, they were the real outcasts, since they occupied those few ecological niches that the ruling class ignored with magnificent negligence.
The food supply of herbivorous dinosaurs were gymnosperms and ferns, which were widespread in the Devonian. The angiosperm, or flowering, flora, which appeared at the beginning of the Cretaceous period, was forced to settle in the margins, since gymnosperms dominated. Thus, flowering plants were just as marginal as small Mesozoic mammals. They had no choice but to occupy empty lands where there were no established communities of gymnosperms: landslides, burnt areas, river banks, that is, such biotopes that are usually called “disturbed.” And the species themselves that settle in such conditions are called “coenophobic” by biologists, that is, they are afraid of communities and prefer to exist separately.
However, the tactical loss ultimately turned out to be an important strategic advantage. Firstly, the flowering plants that had settled on the “bad” lands no longer allowed gymnosperms there, and secondly, they had a flower, which played a decisive role in the struggle for existence. If gymnosperms, for the reproduction of their own kind, relied entirely on the wind, which passively carried their pollen, and therefore were forced to settle in clusters, then flowering plants actively attracted insects, which increased their viability by an order of magnitude.
The existence of flowering plants did not depend on the elements, and the angiosperm flora could afford the luxury of living in scattered wastelands. In addition, a new type of flora has learned to form herbaceous forms that not only effectively counteract erosion, but also quickly take over vacant land.
The change in plant communities turned into a real disaster. Contrary to popular belief, not only dinosaurs became extinct, but also 25% of the Mesozoic families of invertebrates - cephalopods and bivalves, single-celled radiolarians, diatoms, foraminifera and other representatives of planktonic organisms. Their calcium shells formed enormous deposits, which is why this period of the geological record was called the Cretaceous.
Thus, yesterday's inconspicuous outcasts - flowering plants and mammals - crushed the dominant fauna and flora of the Mesozoic.
The onset of flowering plants is now commonly called the great angiospermization (from lat. angiospermae- "angiosperms"). When the new type of flora began to decisively predominate, what always happens when the foundation is destroyed: the building simply collapsed. After all, the plant kingdom is precisely the foundation on which the floors of herbivorous animals and predators stand, and they are connected to each other not only by food chains, but also by more complex relationships.
Dinosaurs tried to master a new diet - they developed beaks and powerful dental batteries for grinding highly abrasive food. However, this did not work out well for them, especially in cereal pasture systems, where they obviously lost to ungulates. In addition, herbaceous flowering forms form turf, which reduces erosion and the runoff of organic matter into fresh waters and the oceans, which has dealt a severe blow to marine invertebrate communities.
The thing is that the overwhelming majority of the creatures that inhabited the planet in the Late Cretaceous moved too far along the path of narrow specialization. For the time being, this gave them excellent chances of survival, but every advantage sooner or later turns into a disadvantage. Attachment to gymnosperm communities eventually played a cruel joke on the lizards: when the flowering plants went on the offensive, taking away one territory after another from the previous masters of life, the mammals easily joined the newly formed communities. But dinosaurs were unable to do this and found themselves in an evolutionary dead end, since their adaptive resources had long been wasted. And for marginalized mammals, this turn of events was only to their advantage. Having survived an explosion of speciation under new conditions, they populated the entire planet.
Of course, not only such large taxa as a class of animals or a phylum of plants can be marginal. Individual biological species, as a rule, also do not exhibit complete uniformity across the entire set of characteristics. Moreover: the higher the genetic diversity of a species or population, the greater its adaptive potential. Such a community will almost always find a way to prolong its existence under changed conditions. And even with a stable and measured life, intraspecific marginals can play an important role.
For example, winged individuals are rarely found in populations of wingless water striders. There are very few of them - only 4%. They have genetic differences, but at the same time they can interbreed with their wingless companions and produce offspring. It turned out that these flying degenerates are capable of migrating over fairly long distances, thus ensuring genetic continuity between the water-dwelling population of all water bodies. Four percent of the marginalized population is more than enough to accomplish this task.
It must be said that almost every biological species has, just in case, an emergency reserve in the form of a rare genotype or an unusual form, which allows it to survive difficult times. Let us repeat once again: the genetic diversity of a species or population is the key to its evolutionary success, so the marginalized should be treated not only with respect, but also with care.
So, the emergence and widespread distribution of flowering plants at the end of the Early Cretaceous (about 30 million years before the death of dinosaurs) not only radically changed the structure of continental communities, but also destroyed the Mesozoic dinosaurs, which had lost their plasticity, hopelessly stuck in dead ends of evolution. Of course, climatic disturbances could also play a role, but the key event, the starting point, was almost certainly this fact - the onset of angiosperms.
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From the author's bookDinosaurs master the air The modern world is replete with flying creatures - insects, birds, bats; there are others who, although not real flyers, are no longer quite land dwellers - tree frogs, squirrels, woolly wings, lizards - “flying dragons”.
Dinosaurs ruled our planet for 130 million years - 100 times longer than the human race has existed on Earth. And 65 million years ago, dinosaurs went extinct. But 65 million years ago, dinosaurs weren't the only ones who had it bad. Then, in general, difficult times came on Earth. Life on the planet was in mortal danger. Flying reptiles have disappeared. Waterfowl reptiles have become extinct in the oceans, as have shellfish and starfish. Even most of the small animals - plankton - became extinct.
Nobody knows for sure. But there are a great many theories. Most of them suggest that there were some strong changes in the climate of our planet, which damaged many living organisms, not just dinosaurs. The latest and most popular theory claims that dinosaurs and other animal species became extinct due to one terrible universal catastrophe: 65 million years ago, the Earth collided with an asteroid, and a terrible explosion occurred.
: In addition to dinosaurs, flying reptiles and a large number of marine inhabitants became extinct 65 million years ago.
By examining clay deposits in layers of the Earth's crust dated to have been deposited 65 million years ago, scientists have found high levels of iridium in these rocks. Iridium is rarely found on Earth, since during the formation of our planet, iridium, as a heavy element, sank deep underground and is found mainly near the earth's core. Iridium only reaches Earth from space when meteorites and asteroids fall from the sky. Scientists have found iridium in ancient clay deposits around the world. Here is their conclusion: the iridium fell from a cloud of dust that was thrown into the atmosphere when the asteroid collided with the Earth. Here's what could have happened.
Related materials:
The emergence of dinosaurs
Dinosaur extinction hypothesis
An asteroid with a diameter of 10 kilometers or more flew from space into the Earth's atmosphere at a speed of at least 100,000 kilometers per hour. Having crashed into the Earth, it formed a crater with a diameter of 160 kilometers. Tons of crushed rocks and soil (a mixture of asteroid and Earth rocks) flew high into the sky from the explosion. Hurricanes arose from the passage of the fireball through the atmosphere and the explosion in the atmosphere, which carried the dust that shot up into the sky throughout the Earth. The sky was clouded with a huge dust cloud. The sun darkened and day became night. The darkness continued for months. The average daily temperature dropped from plus 19 to minus 10 degrees Celsius. The mass death of plants and animals caught in the darkness and cold began.
Following the herbivores, predators that fed on herbivores began to die out. In the end, the cloud sank to the ground, leaving a memory of itself in the form of a large admixture of iridium. Many scientists, however, are skeptical about this theory. Why then, they ask, did birds, crocodiles, turtles, snakes and most mammals survive, as well as insects, shellfish, ocean fish, and many plants? This theory is also questionable because the extinction of dinosaurs occurred very slowly - over millions of years, and not during one giant cataclysm.
Interesting fact: The asteroid that caused global catastrophe and led to the extinction of the dinosaurs may have collided with Earth in the Yucatan Peninsula.
There are scientists who argue that iridium could be mixed with sedimentary rocks during the eruptions of numerous volcanoes, when lava erupts from the deep bowels of the earth. Volcanic eruptions could throw so much ash into the atmosphere that it would obscure the sun as much as dust from an asteroid explosion. This could also be the reason for the extinction of dinosaurs.
