Svetlana Galitskaya
Children's project “Why dinosaurs became extinct”

Text presentation by the student, accompaniment of the presentation, independent experimentation on topic: "Why did dinosaurs become extinct??"

Section: "My first educational and research project»

(natural science direction)

Yudin Danil,

MADO TsRR-d/s No. 16 "Cockerel"

Tbilisi district,

Tbilisskaya village

Scientific supervisors:

Galitskaya Svetlana Petrovna,

senior teacher,

Skryabina Irina Georgievna,

teacher

MADO TsRR-d/s No. 16 "Cockerel"

Tbilisskaya village

« Why did dinosaurs become extinct?»

Danil Yudin

MADOOU TsRR – d/s No. 16 "Cockerel"

annotation

My parents instilled in me a love of learning new and interesting things in the world around me. What I like most is listening to my mother read, studying and looking at illustrations, watching TV shows and films on the topic « Dinosaurs» .

I asked my parents a question:

- Why did dinosaurs go extinct?, but the frogs, snakes, lizards and turtles that lived with them did not. It would be funny if Diplodocus looked into our window now, what would we do then?

Hypothesis: reason for disappearance dinosaurs- This climate change in the surrounding world, to which dinosaurs couldn't adapt.

Target: explore possible causes of extinction dinosaurs, choose one that is most suitable.

Object of study: dinosaurs.

Tasks:

1. Structural features dinosaurs.

2. Learn extinction hypotheses dinosaurs.

3. Conduct a survey among children in your group, preschool teachers, and parents « Why did dinosaurs become extinct??»

4. Find the answer to your question « Why did dinosaurs become extinct??»

A long time ago…

A long time ago, our planet Earth was just a ball of fire, its surface covered with volcanoes and deserts. Under such conditions, life on the planet was impossible.

The first signs of life appeared in the ocean 3 billion years ago - these were bacteria and algae, then animals like worms and jellyfish appeared, then sea sponges, mollusks with hard shells and the first fish. Plants developed on land - moss, ferns, and the first insects appeared.

250 million years ago reptiles appeared - dinosaurs, which translated means "terrible lizard".

Fossils…

Scientists learned about the existence of ancient animals from fossils remains: after death torso dinosaur covered with sand by the wind or filled with water and mud, for example, during a landslide or earthquake. Over millions of years, the sand hardened and turned the bones into minerals as hard as rocks. Paleontologists - seekers, very carefully dug up the found remains, and then studied and collected from them entire skeletons of various dinosaurs. Searchers carried out excavations in different countries planets: in Germany, South Africa, China, Mexico, India.

What were they like...

To this day, more than a thousand species of reptiles have been studied. Dinosaurs unusual and very various:

Some of them were no larger than a chicken, while others weighed as much as 20 elephants;

Some are herbivores, while others are predators;

Some knew how to swim perfectly, while others could fly;

Some were toothy and had more than a thousand teeth in their mouths, some chewed vegetation with only two teeth.

Limbs dinosaurs were located directly under the body to make it easier to move without swaying from side to side.

Some were able to move with large leaps on their hind limbs, while their front limbs were very short.

Their bodies were covered with scaly and sealed skin.

They laid eggs protected by a strong shell, and some knew how to build nests.

What actually happened...

65 million years ago dinosaurs have simply disappeared from our planet. To explain this, scientists from many countries have studied and are now studying the reasons for their disappearance; history knows of assumptions about worldwide disasters:

The first is the hypothesis of W. Alvarez about the collision of planet Earth with a giant comet. The fall should have left huge craters, but scientists never discovered them.

The second is about an asteroid falling into the ocean, then died out would have been all the inhabitants of the ocean, but this did not happen.

The third is about the explosion of a distant star similar to the Sun, but astronomers have not found traces of such a star in the solar system.

The fourth is the hypothesis of J. Cove, about a volcanic eruption, but there were not volcanoes all over the earth.

Not one of the hypotheses has ever been proven by scientists.

Conclusion…

Summarize, dinosaurs died gradually due to several events - a volcanic eruption, an earthquake, and a comet fall, all of which affected the Earth's climate. After this, the plants began to change, the herbivores had nothing to eat, they began to die, and after them, having no food for themselves, predators began to die.

Life on Earth is designed in such a way that some animals die out, while others appear again. This suggests that wildlife and the surrounding world are closely related.

Giraffe - brachiosaurus,

Rhinoceros - Triceratops,

A bat is a flying lizard,

Crocodile – geosaurus and others.

- I want to remind everyone:

Let's protect nature, preschoolers!

We must not forget about her for a minute.

After all, birds, animals, fields and rivers,

This is all for us forever!

« Why did dinosaurs become extinct?»

Danil Yudin

MADOOU TsRR – d/s No. 16 "Cockerel"

Educational and research project

Educational Job: "What is a volcano?"

Goal and tasks: introduce the legend of the origin of the name "Volcano". Look at illustrations depicting volcanic eruptions, discuss how the eruption affects the surrounding nature and wildlife. To promote the development of skills to independently express one’s point of view and reason.

I spit fire and lava, This is a mountain,

I am a dangerous giant, There is a hole at the top,

I am famous for my evil fame, It’s hot inside!

What is my name? Sometimes it releases lava

(Volcano) There's no way to control her

What do you think a volcano is?

A mountain with a hole at the top through which magma pours out, smoke rises and stones fly. A volcano is a fire-breathing mountain.

What does the mountain look like?

On a cone, on a triangle.

What does a volcano erupt?

Hot lava pours out of the volcano. Gas, ash, and hot stones are released into the atmosphere.

"About ancient god Volcano".

“There lived a god named Vulcan. And he liked blacksmithing case: stand at the anvil, hit the iron with a heavy hammer, fan the fire in the forge. He built himself a forge inside a tall mountain. And the mountain stood right in the middle of the sea. When Vulcan worked with his hammer, the mountain trembled from top to bottom, and the roar and roar echoed far around. From the hole at the top of the mountain, hot stones, fire and ash flew with a deafening roar. “The volcano is working!”– people said with fear, and went to live away from this place.

Since then, people began to call all fire-breathing mountains volcanoes.”

Research: "Experience "Eruption".

Goal and tasks: to cultivate interest in cognitive and research activities, strong-willed qualities - perseverance, determination, independence. Acquaintance with a natural phenomenon - a volcanic eruption. Expand the prospects for the development of search and cognitive activity by including the child in thinking, modeling and transformative actions.

Material:

1. On a tray - a jar of baking soda, a jar of food grade citric acid, a jar of red gouache, a jar of water mixed with soap. "Test", teaspoon, napkin.

2. Layout "Habitat dinosaurs» - plastic trees and figures dinosaurs, a volcano mountain with a crater, made of construction foam and painted with gouache.

Experience progress:

1. Place one teaspoon of baking soda into the crater of the volcano.

2. Add one teaspoon of food grade citric acid.

3. Mix carefully.

4. Add a little red gouache.

5. Carefully pour in a teaspoon of water mixed with a soap solution - 3-4 tablespoons.

6. Observe the seething - the eruption of lava from the crater of a volcano.

Questioning.

Children from the preparatory group were asked to answer the question « Why did dinosaurs become extinct?» :

Disasters:

1. Asteroid impact.

2. Collision with a comet.

3. Nova Explosion solar system.

4. Volcanic eruption.

Lack of food.

Diseases dinosaurs.

Changing of the climate:

1. Ocean cooling.

2. Changes in seasonal air temperature.

3. Increased icing of the North and South Poles.

Bibliography.

1. « Dinosaurs» Joachim Oppermann, translation from German by V. F. Polezhaeva, 1994. Artist Manfred Gorbeck, editor A. V. Gura. typesetting and films of the Russian text were made by the publishing house "Word", 1993.

2. Collection cards "In the World of Wildlife", publisher LLC International Masters Publishers, 2011-2012.

3. N. N. Malofeeva Encyclopedia of preschoolers - M.: ZAO "Rosman-Press", 2008. – 200 p., 2006.

4. "Who? Where? Why?» Illustrated encyclopedia for little ones why check/ translation from English by V. V. Stepanova. – M.: AST: Astrel, 2010. – 173, p.: illustrations LLC "Publishing house Astrel", 2009.

5. A fun encyclopedia. Dinosaurs [Text]/Claude Bogaer; translation from French by P. Buntman; [artist G. Regalado]. – M.: Labyrinth Press, 2012.

6. Matthews Rupert "Atlas dinosaurs» /Translation from English by V.V. Naidenov. - Smolensk: Rusich, 2002. – 64 p.: illustrations.

7. Rublev S. “New atlas of animals for children. – Rostov n/d.: Vladis: M.: RIPOL classic, 2009.-48p.

8. "Animal Atlas"/Translation from French c. V. Naydenova. - Smolensk: Rusich, 2011.-48p. Computer layout: E. Mikhalkina. Text: L. Cambournak.

9.Larousse "My first encyclopedia", edition in Russian by Sergey Dmitriev, translation from French by Natalia Speranskaya, 1994, edition "Perseus", "Veche", AST, 1994.

10. Encyclopedia "Living World" Leslie Colvin and Emma Spear. Translation from English by G. I. Rozhkova. Publishing House LLC "ROSMAN-PRESS", 2001.

11. Everything about everything. Ginny Johnson "Ancestors dinosaurs» /translation from English by A. Blaze; design by I. Salnikova; illustrations by N. Hussain. – M.: "Premiere", "Astrel", AST, 2000. – 40 p.

12. Discs VVS collection Vol.2 LLC "Media Alliance" 420107 Kazan, st. Petersburgskaya, 496, 2012.

13. www.dinosaur.ru – website about Dinosaurs.

14. http://ru.wikipedia.org – Wikipedia about Dinosaurs.

15. Bondarenko T. M. “Environmental activities for children 6-7 years old”.

About 66 million years ago, at the boundary of the Cretaceous and Paleogene periods, one of the five “great mass extinctions” known to science occurred, during which 80% of living creatures living on Earth died. The scale is amazing: almost all types of dinosaurs disappeared almost instantly, and the surviving animals underwent radical changes. However, scientists are still at a loss as to what caused this. There are dozens of theories explaining the extinction of dinosaurs, but none of them can be called 100% reliable. Let's find out about the 10 most popular versions in scientific circles.

10. Asteroid

One of the well-known theories is that the extinction of dinosaurs occurred due to the collision of the Earth with a huge asteroid

One of the most famous theories is that the extinction of dinosaurs occurred due to the collision of the Earth with a huge asteroid. Scientists have recorded incredible high level iridium content in sedimentary rocks corresponding to the Cretaceous-Paleogene period. Iridium is rarely found in the earth's crust, but is one of the main minerals in asteroids. There was only one problem: if such a gigantic cosmic body fell to Earth, it means there must be a crater somewhere. And it was found in 1990 near the Yucatan Peninsula (Mexico). The crater was named Chicxulub, its diameter is 180 kilometers, and the original depth, according to scientists, reached 18-20 kilometers. It is believed that it was formed after a collision with an asteroid with a diameter of about 10 kilometers. The impact energy was equal to 100 teratons in TNT equivalent (the most powerful thermonuclear device in history had a power of only 0.00005 teratons).

It is believed that the impact caused a devastating tsunami 100 meters high that penetrated deep into the continents. A shock wave also passed across the surface of the planet, and high temperatures led to forest fires around the world. A huge amount of soot was released into the atmosphere. The concentration of carbon monoxide in the air has increased hundreds of times. The surface of the Earth was closed from the direct rays of the Sun for many years by soot and dust clouds. Due to the lack of light, photosynthesis in plants slowed down significantly, which led to a decrease in oxygen content in the atmosphere. And by the time the clouds cleared, all the dinosaurs had already disappeared.

9. Global Firestorm

One theory suggests that after the asteroid hit the Earth, a real firestorm began that engulfed the entire planet.

While most scientists agree that the Earth collided with an asteroid, they cannot agree on what exactly caused the extinction. One theory suggests that after the impact, a real firestorm began that engulfed the entire planet. The point is that during the collision, the smallest particles of rock were thrown high up. Gradually they formed grains of sand that began to fall into the atmosphere. There they became hot from friction with air, the temperature reached 1500°C. The sky turned bright red, and the entire planet was drowned in flames from fires spreading across the entire land. The researcher who developed this theory compared what was happening then with the consequences of dropping megaton bombs on every 7 square kilometers of the Earth's surface. Only animals that managed to hide in holes or under water had a chance of surviving the fiery tsunami.

8. The most powerful hurricanes

According to scientists from the Massachusetts Institute of Technology, a powerful hurricane could have caused the extinction of dinosaurs.

Scientists from the Massachusetts Institute of Technology were able to simulate on a computer another scenario for the extinction of dinosaurs. In their opinion, the cause could have been a powerful hurricane. Theoretically, it was caused by the heating of a large area of ​​water in the ocean (about 100 square kilometers) to a temperature of +50°C after a meteorite impact. Under such conditions, hurricanes would arise whose speed reached 1,100 kilometers per hour. For comparison: the most powerful hurricane in history is dated October 12, 1979. The wind speed then reached 350 kilometers per hour - only 30% of the above number.

Dinosaurs could still survive powerful hurricanes, but the fatal circumstance for them was that the wind rose to a height of up to 75 kilometers. Soon the ozone layer was destroyed, and the deadly solar radiation literally incinerated almost all life on the planet. Its restoration took several decades.

7. Gradual extinction due to competition from mammals

Mammals turned out to be more adapted to life; it was easier for them to find food and tolerate environmental changes

Less dramatic is the theory that claims that dinosaurs did not die out instantly, but gradually, over several million years. The likely reason was fierce competition with mammals. The latter turned out to be more adapted to life; it was easier for them to find food and endure environmental changes.

The main difference between mammals and fossil lizards is the method of reproduction. Cold-blooded dinosaurs were known to lay eggs. Mammals gave birth to live young and then nursed them. Newborn dinosaurs were small, so for growth and development they needed a colossal amount of food, which became increasingly difficult to obtain. Finally, mammals carried children in the womb, while lizard eggs were vulnerable to predators who loved to feast on them. Everything is natural: a less developed and adapted to external conditions form of life gave way to a more advanced one.

6. Continental drift

Initially, all the continents made up a single giant continent called Pangea

Dinosaurs, according to scientists, lived in the Mesozoic era (248-65 million years ago). The Mesozoic, in turn, is divided into the Triassic, Jurassic and Cretaceous periods. Initially, all the continents made up a single giant continent called Pangea. During the Jurassic period, Pangea gradually “broke” in half, and land parts began to move away from each other. By the time of the extinction of the dinosaurs, the continents had moved even further apart. The contours of the continents began to resemble modern ones.

Continental drift could have caused the extinction of dinosaurs, because their habitats changed dramatically, as did climatic conditions. The vegetation has changed, and it has become more difficult for herbivorous lizards to get food. With their numbers declining, hard times also came for the carnivorous dinosaurs.

5. Changes in sea levels

Each period of mass extinction coincides with times of dramatic changes in global sea levels

There have been 5 mass extinctions in Earth's history. Professor Madison from the University of Wisconsin believes that sea level changes were their “main culprit.” The earth was formed 4.5 billion years ago, but liquid water appeared on it much later. Interestingly, each period of mass extinction coincides with times of dramatic changes in global sea levels. New land areas emerged from under the water, while the usual habitats of animals were flooded. Accordingly, the vegetation and climate of these territories also changed. The lizards were unable to adapt to such drastic changes.

4. Diseases

Many dangerous infections began to appear around the time of the extinction of the dinosaurs.

While examining the remains of mosquitoes and ticks forever stuck in amber, Dr. George Poinar of the University of Oregon made an unexpected important discovery: It turns out that many dangerous infections began to appear around the time of the extinction of the dinosaurs. Perhaps the mighty dinosaurs disappeared from the face of the Earth due to a plague epidemic.

This disease would be devastating for them. The fact is that dinosaurs did not have a developed immune system, and they reproduced quite slowly. Infected individuals would quickly infect all their relatives with a fatal disease. Mammals were able to survive due to a more developed immune system.

3. Comet

Comets are composed primarily of ice, dust, rocks, organic compounds, they are smaller in size, so they develop high speed

According to a theory presented to the world in 1980, the death of the dinosaurs was caused by a comet hitting the Earth. This cosmic body consists mainly of ice, dust, rocks, and organic compounds, while asteroids are made only of stone and metal. Comets are also smaller, so they can reach higher speeds.

Critics disagree: in their opinion, the comet could not have been so large that its collision would have formed the Chicxulub crater. However, computer modeling showed them to be wrong. If the comet was moving at great speed, a crater of similar diameter could still form. Interestingly, in this situation, many times more dust and debris would rise into the atmosphere than during a collision with an asteroid.

2. Vulcan

For millennia, the Earth was surrounded by a continuous layer of dense clouds with a high sulfur content, which did not allow sunlight to pass through.

Another theory says that the extinction of lizards was caused by the eruption of volcanoes belonging to the Deccan Traps (one of the largest volcanic formations on the planet). This area is located on the territory of modern India. During an eruption, sulfur would be released into the air for 10 thousand years. And the total volume of gases and dust entering the atmosphere was 10 times greater than in the case of a collision with an asteroid. For millennia, the Earth was surrounded by a continuous layer of dense clouds with a high sulfur content, which did not allow sunlight to pass through. The result was the oxidation of water in the world's oceans (accompanied by the death of the vast majority of its inhabitants) and sharp warming caused by the greenhouse effect.

This theory received further confirmation in 2009. Then, undersea oil drilling off the coast of India discovered massive eons of ancient solidified lava filled with sediment. The lava contained fossils dating back to the period of extinction of the dinosaurs.

1.Combination of different reasons

Dinosaurs that survived natural disasters may have disappeared a little later due to disease or climate change

Many of the events listed above could have occurred almost simultaneously - that is, in a relatively small period of time on the scale of the epochs of the Earth's existence. Researchers debate what exactly led to the death of dinosaurs, but few deny this fact. For example, there is evidence that the collision of an asteroid or comet with our planet and powerful volcanic eruptions occurred at approximately the same time. Moreover, the fall of a celestial body to Earth could trigger the start of fires on all land areas.

The dinosaurs that miraculously survived these catastrophes could have disappeared a little later due to disease or climate change. Competition from mammals may also have played a big role. This version seems to be the most likely: most likely, the dinosaurs were simply very unlucky. They might have survived each cataclysm separately, but not all at once.

Introduction

Life on Earth arose about 3 billion years ago; it began with tiny single-celled creatures, and about 225 million years ago, dinosaurs appeared on Earth in the process of evolution. They inhabited the Earth for approximately 160 million years, i.e. over a period 50 times longer than the period from the appearance of man to the present day. Not all types of dinosaurs existed at the same time: some species died out, others arose.

Dinosaurs were well adapted to their environment. Some of them were herbivores, others were carnivores, so there was enough food for everyone. Dinosaurs had very tough skin, some species had huge massive bodies and long necks, while others were no larger than a turkey. Dinosaurs reproduced by laying eggs with a hard shell that well protected the embryo during development.

How did it happen that dinosaurs, which dominated the Earth for so long, suddenly disappeared 65 million years ago? The answer to this question interests many, which is why there are many hypotheses about the reasons for the mass extinction of dinosaurs. We'll look at some of them.

Searching for traces of the past

The first dinosaur bone was found by the English naturalist Robert Plot in 1677. At that time, no one had any idea that animals that were different from modern ones once existed on Earth. The discovery of the Raft was considered the bone of an old elephant or even some kind of giant. The first documented dinosaur tracks were discovered in 1802 in Connecticut (USA) by the peasant Plinyo Moody. On a stone slab found in his field, there were prints of three fingers, which were attributed to ... “the claws of the raven released from Noah’s ark after the Flood.”

The word "dinosaurs" was first used by Richard Owen on August 2, 1841. The term is derived from the Greek deinos - terrible and sauria - lizard, so dinosaur means "terrible lizard". After studying many fossil remains, Owen came to the conclusion that these animals had much in common with each other and were the largest in size among all reptiles. The first images of ancient monsters, made from found fragments, immediately appeared, and life-size sculptures of dinosaurs began to entertain visitors to major exhibitions.

From the middle of the 19th century. Amateurs and professionals began searching for dinosaur remains all over the world. Violent passions flared up in the Far West of the United States between 1870 and 1890. The expeditions of two outstanding American paleontologists, Edward Cope and Othniel Marsh, discovered huge dinosaur cemeteries in the Rocky Mountains (Canada). The most expensive expedition was organized by the Berlin Academy of Sciences to Tendaguru (Africa) in 1907. It cost 200 thousand German marks. Over 1,500 people discovered more than 250 tons of fossil remains over 3 years of work. During their study, scientists came to the conclusion that among the lizards there were small, medium, large and simply huge lizards. The body length of dinosaurs ranged from 20 cm to 30 m. In total, there are currently about 1 thousand species of dinosaurs.

The most ancient dinosaurs were land predators, then herbivores appeared. Some of them switched to life in water. Ancient dinosaurs were bisexual, but scientists still do not know for sure how males differed from females. It is assumed that among horned dinosaurs, males had longer and more massive horns, which could be used as tournament weapons. Male duck-billed dinosaurs had a longer crest on their heads than females. It is even assumed that some forms, differing in morphological characters and sizes and described as different species and genera, represent males and females belonging to the same species.

Dinosaur groups

Based on the type of food they eat, dinosaurs are divided into predators that walked on two legs, herbivores and scavengers. They lived alone or in groups, in both warm and cold climates. Some hunted, which required not only muscular, but also intellectual effort. The anatomical features (massive hind limbs, huge body and vestigial forelimbs) of giant predatory dinosaurs created a serious problem: if they fell, they were not able to get back to their feet, because. they could neither lean on their weak forelimbs nor tuck their hind legs under their heavy body.

The distribution of dinosaurs into groups does not depend on their size, mode of movement and nutrition.

Based on the structure of the pelvic bones, dinosaurs are divided into two orders: Lizard-pelvic (Saurischia) And ornithischian (Ornitschia). The differences between them are as follows. The pelvis of four-legged animals consists of three pairs of bones: the pubis, the ilium and the ischium. In lizard-pelvic dinosaurs, the ilia point upward where they connect to the sacrum, the ischia point downward and backward, and the pubis point forward and downward. In ornithischian dinosaurs, the ischial and ilium bones are arranged in the same way, and the pubic bones have two branches directed in different directions: one forward and the other backward, parallel to the ischial bones. The significance of these differences is not clear.

The differences between groups of dinosaurs in the structure of the jaws and teeth and the associated differences in nutrition are easier to explain. In lizard-hipped dinosaurs, the teeth were located along the edge of the jaw in one row, which reached the end of the muzzle. Each conical or chisel-shaped tooth sat in a separate cell. Ornithischian dinosaurs had a toothless predentary bone in the front part of the lower jaw; front teeth were often absent in the upper jaw. Many ornithischians had a horny beak, like turtles. In addition, the lateral teeth were moved inward from the edge of the jaw, and their arrangement was multi-rowed. This displacement of the teeth is due to the fact that the cheeks were located outside the jaws. This made it possible to hold food in the mouth while chewing. Lizard-hipped dinosaurs did not chew.

All ornithischians were herbivores and walked on either two or four legs. Among the lizards there were both herbivores and predators, which, for the most part, were bipedal.

Like all archosaurs, dinosaurs had a diapsid type of skull with two, and not one, like other reptiles, temporal sockets behind the eye sockets. This made the skull lighter, freed up space for the development of powerful jaw muscles, contributed to better action of the jaws when feeding, and also contributed to the improvement of the hearing aid.

Another characteristic feature, characteristic of dinosaurs, was the structure of the pelvic girdle and the placement of the limbs, which ensured greater mobility of the animals. Unlike other archosaurs and most reptiles, dinosaurs' hind legs were straight and moved in a vertical plane when walking, like birds and mammals. Most other reptiles (for example, crocodiles, lizards, turtles) have paws widely spaced to the sides. In the pelvic girdle, dinosaurs had a complex sacrum of five fused vertebrae and a perforated acetabulum, into which the head of the femur entered. These anatomical features made dinosaurs the most mobile of the land inhabitants of the Mesozoic.

A – four-radial pelvis with free space below;
B – triradiate pelvis with pubic bones directed forward

One of the amazing features of some large herbivorous dinosaurs, both lizard-hipped (diplodocus, brachiosaurs) and ornithischians (stegosaurs, ankylosaurs), not present in any other animals, was the presence of a second brain (this is reflected in the generic name of one of them: "Diplodocus" translated from Greek means "two minds"). The volume of the brain inside the fused sacral vertebrae of the pelvic girdle was 10–100 times greater than the volume of the brain. The question arises, which brain, the hindbrain or the forebrain, was the main one? It is believed that the hindbrain coordinated the work of the limbs, the forebrain coordinated food activity and sensory organs. This “decentralization” of brain functions, some researchers believe, was one of the reasons for the extinction of dinosaurs.

Hypotheses about the causes of the mass extinction of dinosaurs

From the Triassic to the Late Cretaceous, dinosaur diversity increased. It seemed that nothing foreshadowed their disappearance without a trace. But at the end of the Cretaceous period, the entire prosperous group of planetary owners died out. The extinction of species is a natural evolutionary process. It usually occurs slowly and unevenly. But the speed with which the largest group of reptiles disappeared is amazing.

Hypotheses about how this happened can be divided into two groups:

– hypotheses explaining extinction by external, including extraterrestrial, causes;
– hypotheses linking extinction to internal, biological factors.

Hypothesis 1

The first group includes the hypothesis that on the territory of India, in the Deccan region, lava oozed abundantly from a giant fault 400 km long and there was unbearable heat. Volcanoes released huge amounts of carbon dioxide into the hot air. It was almost impossible to breathe such air. Clouds of ash and sulfur, escaping from the vents of volcanoes, rose high into the sky and enveloped the entire Earth. The atmosphere was poisoned by poisonous volcanic gases, and the soil by endless acid rain. Plants died from lack of light, followed by herbivores, and then predators. It started to get colder on Earth. Then the ash settled, and the cold was replaced by heat again. Carbon dioxide (then there was 10 times more of it in the atmosphere than today) created the “greenhouse effect”. Heat was retained near the surface of the Earth, and the air began to warm up, rains became rare, lakes and swamps dried up, and many rainforests were replaced by deserts. The drying out of coastal shallow waters with their rich fauna and the increase in the overall salinity of the Ocean led to the extinction of 95% of marine animal species. And then a new emission of ash darkened the sky again, and the cold returned to the planet. Such sharp climate changes continued for more than 600 thousand years. As a result, only species less specialized than dinosaurs, such as mammals, survived.

Hypothesis 2

Another common version of the death of the Cretaceous giants is the fall of a huge meteorite near the village of Chicxulub (Mexican island of Yucatan). A meteorite that weighed thousands of billions of tons left behind a crater 200 km across! The power of the impact was comparable to the explosion of so many atomic bombs, which is 10 thousand times greater than the current world supply. A monstrous air wave destroyed most of the land species of plants and animals, earthquakes swept across the planet, and giant tsunami waves circled the Earth several times.

This hypothesis appeared in 1970. Its factual basis is evidence from the geological record: in many areas of the world, in marine and continental sediments, a small layer of clays with an unusually high content of platinum group elements was discovered, in particular iridium, rare in the earth's crust, but widespread in meteorites element. Such a layer is believed to have formed only if the sediments were "diluted" by large amounts of meteorite material. Having estimated how much such a meteorite could weigh, scientists turned their attention to an ancient crater near the village of Chicxulub. The time level of the layer exactly coincides with the time when the last dinosaurs, as well as other groups of terrestrial and marine animals and plants, disappeared.

The dust raised as a result of the explosion made the atmosphere almost opaque to sunlight for several years. The photosynthetic activity of green plants, which are the initial link in the food pyramid, has sharply decreased. Further, as if in a chain, the extinction of various groups of marine and terrestrial organisms occurred.

Hypothesis 3

It is believed that rapid climate change, which led to mass extinction of species, could be caused by continental drift and changes in the direction of winds and sea currents. On the continents, the change of seasons sharply became apparent: hot summers began to give way to cold winters, when herbivorous dinosaurs were deprived of green food. Dinosaurs were unable to adapt to seasonal temperature changes. However, there are no facts confirming such a catastrophic acceleration of the drift of continental plates.

Location and directions of continental drift during the Cretaceous period

Hypothesis 4

In the middle of the Cretaceous period, the largest restructuring of the planet's vegetation in the history of the Earth took place: angiosperms (flowering) plants and grass appeared, and cereals became increasingly widespread. For herbivorous animals that ate more primitive plants, the transition to another diet required a significant restructuring of the entire enzymatic digestive system. It is possible, although very doubtful, that they were unable to overcome this physiological conflict.

Hypothesis 5

Recently, scientists have put forward a new hypothesis for the extinction of dinosaurs - at least some carnivorous species. Prehistoric lizards fell victim to the discrepancy between the energy needs of their gigantic organism and the objective possibilities of satisfying them. Experts from the British Zoological Society link this version with the answer to the question of why nature did not create, say, a lion or a tiger the size of an elephant. Such a huge carnivorous creature would not be able to hunt fast enough to replenish its energy needs in time, they believe. According to scientists, evolution should ultimately lead to the fact that carnivores with a body weight of more than 1 ton, living on the surface of the Earth, will lose the right to exist due to energy deficiency. However, it is doubtful that this shortage occurred suddenly and led to the extinction of all dinosaurs in a historically short time.

Hypothesis 6

Perhaps the dinosaurs lost the fight for survival with new, rapidly emerging species of mammals and birds. However, this hypothesis lacks factual material to substantiate.

Hypothesis 7

As a result of any catastrophe on a planetary scale, the destruction of the ozone layer could occur, and ultraviolet rays could cause a sharp increase in the rate of mutations in organisms. Perhaps common parts of the dinosaur genomes were unstable to such mutations, which led to the rapid extinction of all their species. Species with stable genomes survived.

Conclusion

A meteorite near the village of Chicxulub and a powerful eruption in the Deccan are the main “suspects” in the case of the death of dinosaurs, which occurred at the turn of the Cretaceous and Tertiary periods 65 million years ago. But for more than 20 years now, scientists have not reached a final “verdict.” The controversy flared up with renewed vigor in March 2004, when Hertha Keller from Princeton University (USA) stated that she had evidence of the “innocence” of the meteorite. She claims that the Chicxulub stone fell to Earth long before the death of the lizards.

The sediments at the site of the famous crater contain fossilized remains of tiny marine animals that went extinct along with the dinosaurs. This layer appeared after the cosmic catastrophe, and its formation took approximately 300 thousand years. According to G. Keller, one Deccan eruption would be quite enough to destroy the dinosaurs, and a meteorite - Chicxulub or otherwise - could be only the last straw that overflowed the cup.

A proponent of the “meteorite” hypothesis, Dutchman Jan Smith, believes that Hertha Keller misinterpreted the results of samples taken in the crater. In his opinion, after the meteorite hit, the crash site was covered by a powerful tidal wave - a tsunami - and went under water, and it took only a few weeks for such a layer of sediment to form.

According to geologist Vincent Courtillot, the death of ancient lizards was not as catastrophic and fleeting as is usually imagined. The latest fossils from that time show that the giant reptiles died out gradually over hundreds of thousands of years. And this is difficult to explain using the “meteorite” hypothesis. Over the past 260 million years, there have been four mass extinctions on Earth, each time preceded by unprecedented volcanic eruptions.

Not everyone agrees with this opinion. Geologist Eric Byufto is confident that for each case of animal extinction it is possible to select a suitable meteorite crater. Well, then, why should all such disasters on Earth have the same cause? Byufto does not argue with the fact that numerous species of animals became extinct regularly, and these dramas were not necessarily associated with sudden catastrophic changes. However, the extinction of animals 65 million years ago was so massive that it is more correct to assume

that it was caused by some powerful and fleeting impact, for example, the fall of a large meteorite. Well, besides, says Byufto, it is difficult to imagine that dinosaurs, who inhabited the entire Earth from the equator to the poles, became victims of sharp climate fluctuations, but, for example, crocodiles calmly survived the boundary of the Cretaceous and Tertiary periods.

So, the time for the final verdict is postponed. Scientists still have to examine meteorite craters again and again, carefully study fossils and, finally, find out why crocodiles survived the dinosaurs...

Literature

1. Laura Cambournac. Dinosaurs and other extinct animals. – M.: Makhaon, 2006. – 123 p.

3. Illustrative encyclopedia: dinosaurs / D. Burney; Artist D. Sibbick; Per. from English I.N. Alcheeva, N.N. Nepomnyashchy. – M.: AST Publishing House LLC: Astrel Publishing House LLC, 2002. – 222 p.: ill.

4. Relatives of dinosaurs / Trans. from English S. Freyberg. – M.: Astrel Publishing House LLC: AST Publishing House LLC, 2002. – 56 p.: ill. – (Secrets of living nature).

5. Dinosaurs. Complete encyclopedia /Trans. from English M.Avdoni-noy. – M.: Publishing house EKSMO-Press, 2000. – 256 p.

65 million years ago, the asteroid "Heavenly Hammer", whose official name at its location is "Chicxulub", struck the Earth, causing a global environmental disaster, and tore out a page called "Dinosaurs" from the history of the planet. Today, the latest scientific data make it possible to draw up a protocol of that “doomsday” with a high probability. Death came without warning, literally falling out of the blue...

A colossal rock fragment measuring ten kilometers across came from the icy depths of space. At a speed of 150 thousand kilometers per hour, it escaped from the asteroid belt between Mars and Jupiter, where it had peacefully moved in an elliptical orbit around the Sun for billions of years. When the asteroid crossed the orbit of the blue planet, which was at that moment in fatal proximity, it was captured by its gravitational field, slowed down and changed its trajectory...

The solar wind licked and rounded the surface of the giant stone with cosmic dust and frozen gases that had become stuck on during long journeys. Evaporating, they stretched out in a long trail, and now the alien was already visible in the sky even during the day, frozen there as a harmless luminous comma. However, accelerated by the planet’s gravity, it swallowed the last 400 thousand kilometers in an instant. The Earth was reliably protected from smaller guests by a dense, humid atmosphere, where they sometimes burned, sometimes were crushed into small meteor showers, without having time to cause much damage. But for an asteroid of this size, it didn’t matter whether there was atmospheric protection...

Leaving a blinding plasma trail in the clear sky, the “Heavenly Hammer” crashed into the earth’s firmament at a speed of 72 thousand kilometers per hour, or 20 kilometers per second. The fatal geometry of the collision - at an acute angle to the surface - aggravated the already severe consequences of the impact. The earth's crust, especially thick under the continents, withstood the onslaught and even sprung somewhat, throwing the asteroid back.

But in these thousandths of a second, its entire mass, which is two thousand billion tons of stone, has already been converted into energy equal to the simultaneous explosion of five billion atomic bombs dropped on Hiroshima. Matter turned into a mess of atoms - plasma, a ball of energy released at one point; a flare brighter than the sun illuminated even near space. In the colossal temperature of the explosion (> 10,000 ° C), billions of tons of earthly rock evaporated; a hellish prominence broke through the atmosphere of the doomed planet and stopped only somewhere halfway to the Moon.

From the flash, within a radius of several thousand kilometers from the epicenter, it almost instantly disappeared, all organic matter and some inorganic matter evaporated.

...the first hours

The shock wave, at a speed of 7,000 kilometers per hour, rushed in different directions from the explosion site and circled the globe many times. The wall of incredibly thick dust whipped up by it scattered in concentric circles over thousands of kilometers, suffocating all living things.

At the site of the collision, a so-called “astrobleme” or “star wound” arose - an impact crater with a diameter of 200 kilometers and a depth of 40 kilometers. Its vertical walls, which rose up for several minutes, again collapsed into the boiling magma below. The fall of multibillion-dollar masses of rock caused a colossal explosion of pressure of five gigapascals, as if water had been splashed onto a white-hot frying pan. A hot prominence was thrown high into the atmosphere, containing, in addition to liquid and gaseous stone, megatons of evaporated sea salt and millions of cubic kilometers of water in the form of superheated steam, because half of the crater was located in the Atlantic Ocean.

When the upward movement stopped, the hot materials of the explosion fell onto the surface of the planet within a radius of 7000 kilometers from the epicenter, covering the Northern and South America; a fiery shower ignited vast areas of virgin forests, and the atmosphere began to fill with impenetrable smoke, the likes of which the world had never known.

As a result of the asteroid impact, vibrations arose in the molten semi-liquid core of the planet, generating a tsunami in the oceans more than one kilometer high, which spread from the epicenter in all directions at a speed of 1000 kilometers per hour, broke through hundreds of kilometers deep into the continents, crumbled and washed away all coastal regions.

In parallel to this, vibrations in the bowels of the planet launched a murderous scenario on land: super-strong earthquakes (or rather, “planetquakes”) with a force of at least thirteen shook the globe, collapsing and smashing everything to dust. We are not familiar with such earthquakes today. Shocks of such force were guaranteed to knock down even 80-ton colossi such as the Brontosaurus (in other conditions very stable creatures); they fell into cracks that opened up everywhere and died under collapsing rocks, which is now being discovered during excavations.

... first days

There was no escape from “quick death” in the first moments and hours after the impact, even in the most remote corner of the globe. It turned out that this was only the beginning of a planet-wide hell; life at great distances simply received a reprieve. The survivor was doomed to die in the fire of endless forest fires, thickening the already impenetrable smog with a smoke screen. The “Heavenly Hammer” hit a kilometer-thick layer of limestone and dolomite, a huge mass of these rocks evaporated, and a terrible poisonous cocktail of a mixture of carbon dioxide and sulfur dioxide was brewed in the atmosphere, as in a huge retort.

... the first weeks... months... years...

The cataclysm has entered its “slow” phase. A few days later, the entire sky above the planet was covered with a funeral shroud - a black cloud (however, it would only be seen as black from below). When passing through the atmosphere, the asteroid ripped a colossal “hole” in it, in which a vacuum arose for several minutes. Based on the principle of traction in a chimney, millions of tons of products from the first explosion rushed into this hole, “sucked” by a giant pump to a height of 40 kilometers.

The hole into space had already closed by that moment, and everything remained in the atmosphere. The second explosion after the crater collapse created a second layer of contamination. Everything gradually dispersed around the globe, the water turned into ice crystals, filling the stratosphere at different levels. From the outside, the planet seemed wrapped in a thick cotton blanket, impenetrable to sunlight; A completely dark night reigned on the surface without the slightest hint of a change in time of day. Today this phenomenon is called “nuclear winter”, which would be the consequence of a global nuclear war.

After a brief spike in temperatures due to the asteroid explosion, planet-wide fires, and magma breaking through to the surface, temperatures everywhere quickly dropped to at least 20°C below normal. The surviving plants, including ocean microalgae, stopped growing, the process of photosynthesis was interrupted, and oxygen ceased to flow into the atmosphere. Due to a sharp reduction in evaporation, precipitation almost ceased; the infrequent rains became a poisonous shower, adding to the agony of the survivors.

The heaviest of the survivors, the herbivorous lizards, were the first to die. The predators received a short reprieve, but even for them the short time of abundance, the “feast in the darkness,” quickly ended, because soon there was no one left to eat. Due to the rapid mixing of the ocean, the upper layers of water, rich in oxygen and life, were absorbed by “dead” water of great depths; all the “little things” died out, the food chain collapsed, the sea giants left the historical arena forever.

Almost all those who survived this phase of the disaster died of hunger and cold over the next months, because the black cloud did not disappear, as happens with rain clouds after a rainstorm; it remained in the atmosphere for years, decades, maybe even centuries! The Great Dying took a long time.

Yucatan Sky Hammer Anvil

Today the place of that terrible event is called by the beautiful Spanish-Creole name “Yucatan”. It is known for its wonderful beaches, palm groves, exotic flavor, it is washed by the gentle waves of the Atlantic Ocean - and there are no visible traces of tragedy. The movement of continental plates has long healed the wound inflicted by the asteroid on the Earth; now this place is covered by a kilometer-thick layer of rocks. Is this really the tomb of “Planet of the Lizards”?

The hypothesis of the disappearance of the colossi of antiquity with the participation of a cosmic object is only one of eighty existing theories. This is supported by the discovery of unusually high concentrations of iridium, a rare earth element found only in the Earth's mantle, in the Italian Apennines. It is present almost everywhere on Earth in precisely the layer of clay that corresponds to the time of the death of the dinosaurs.

The theory is also supported by the small oval granules of black glass tektites found almost everywhere, which are a product of the fusion of microportions of sand under the influence of very high temperatures. In layers of clay with a high iridium content there are up to twenty thousand of them per cubic centimeter! This could only happen as a result of a gigantic ejection of deep matter high into the atmosphere, from where they returned to the earth in the form of precipitation.

Their global distribution confirms that the cataclysm that killed the dinosaurs was not a local emergency, but a worldwide event that affected the entire planet. These two finds - iridium and tektites - became the basis for the theory of the American scientist, laureate Nobel Prize Luis Alvarez, which caused a furor in scientific circles in the 80s: dinosaurs became extinct due to an asteroid impact that provoked hyperactive volcanic activity on the planet.

A little later, a curious incident brought evidence of this hypothesis. In 1981, Mexican geologist Antonio Camargo, on behalf of the Pemex oil concern, undertook geological measurements to localize probable underground deposits. He did not find oil, but he discovered a strange anomaly in the Earth’s magnetic field on a circular underground formation invisible from the surface. It was an astrobleme, a colossal crater.

The geologist came to the only correct conclusion: we are talking about the place where a celestial body fell about 65 million years ago. He reported his discovery at a scientific congress in Los Angeles and... created a storm of indignation! “Scientific luminaries”, often being ossified bureaucrats and opponents of everything that does not coincide with their opinion, immediately rejected the point of view of the “non-specialist”; Pemex even threatened to fire him so that he would search for specific oil, and not mythical lizards.

Fortunately, the report was carefully listened to and recorded by a Texas journalist. In his newspaper article, he recalled the hypothesis of another scientist, Luis Alvarez. The story became public and aroused the interest of the scientific world. So the individual pebbles formed a completely realistic picture of the event. The location of the asteroid impact was clearly established: the Chicxulub crater, Yucatan Peninsula, Mexico.

Latest Research

In order to piece together the Big Impact puzzle as accurately as possible, scientists intend to take the crater seriously. To this end, several months ago a group of geophysicists, geologists, paleontologists and impact specialists began a complex project. Among other things, wells are being drilled to a depth of 1,800 meters; The extracted drill cores are expected to be deciphered using modern methods.

Today's capabilities make it possible to reconstruct with high probability what exactly happened on that day and how. However, all this will take years, according to mineralogists at the Potsdam Center for Earth Geology (Germany), which is responsible for a comprehensive analysis of the crater.

It took life on Earth millions of years to recover from that knockout. Scientists suggest that two-thirds of the earth’s inhabitants died that time; only creatures with a body weight of no more than twenty kilograms, who could still find food sufficient to gain time, managed to survive. Mosses and ferns were the first to return to the devastated regions, followed by other plants, insects and animals.

Those who adapted to a new phenomenon, the cold, had advantages, say, wool. This is exactly what the “weaklings” of that era had - today we call them mammals. The first of them appeared about 200 million years ago, were the size of a mouse, and in the world of giant lizards they were content with the role of universal prey, forced to hide and adapt. New conditions became the beginning of “their era.”

How great is the danger of a new collision between the Earth and an asteroid? According to experts, it is only a matter of time. Scientists have calculated that today a much smaller asteroid would cause such a chain of oscillations in the bowels of the Earth that the resulting tsunamis would wash away the coastal, usually densely populated regions of the planet within a few hours without a trace.

The meteorite that struck fifteen million years ago between present-day Munich and Stuttgart and left a 25-kilometer crater was only one kilometer across, but even this “baby” completely destroyed the then Europe, changing the very geographical contours of the continent. A space object of the caliber of the Yucatan guest would completely destroy today's civilization.

"Big Five" asteroids

There is a version that the source of constant meteorite danger for the Earth is the supposed invisible satellite of our star “Nemesis”. This absolutely black star moves in an orbit passing along the outer perimeter of the Solar system, and from time to time it captures cosmic bodies that are dangerously close with its colossal gravitational field, throwing them inside our system, where they then collide with one or another planet.

Today, experts agree that the development of life on Earth was determined by five proven collisions of the Earth with space objects, each of which radically changed the conditions of existence on the planet: 65, 200, 240, 360 and 440 million years ago.

So what is still known about the mysterious planet "Nemesis"?

Nemesis (Nibiru) is a dark cosmic body: a protostar, in the depths of which thermonuclear reactions have not begun, and by now has already cooled down, or vice versa, a star that has quickly used up its supply of thermonuclear fuel and by now has also cooled down.

One of the reasons for the hypothesis about the existence of Nemesis was the Stone Age rock paintings depicting two suns.

According to a theory actively discussed in the 1970s and 1980s, the star Nemesis revolves around the Sun in a wide orbit. Approaching the Solar System, Nemesis should create gravitational disturbances in the orbits of the planets, the Earth's magnetic field, and even bring down icy planetoids from the so-called Oort cloud onto the Earth.

It is interesting that the Nemesis hypothesis and its “fatal” name were initially required in order to explain the cyclical periods of mass death of almost all life on our planet. This means that further evidence of the existence of Nemesis in reality could have extremely important consequences for our understanding of not only the history of the Earth, but also our own destinies in the future.

The newly discovered brown dwarf is reported to be just 60 AU (astronomical units) (1 AU = distance from the Sun to Earth) from us and is currently moving towards the constellation Sagittarius. Due to periodic gravitational disturbances in the Oort Cloud, a Spanish team of astronomers calculated that G1.9 travels in an elliptical orbit as it approaches the Sun.

You might ask why astronomers have never discovered this object before. In fact, they discovered it a long time ago. G1.9 was first identified as a "supernova remnant" in 1984 by Dave Green of the University of Cambridge, then after more detailed study with the NRAO Very Large Telescope in 1985, it was found to be unusually small for a supernova.

In 2007, X-ray observations from NASA's Chandra X-ray Observatory revealed that the object was much larger than the last time it was seen! It increased in size by 16%. Puzzled by this observation, Very Large Array repeated its observations 23 years ago and became convinced that it had increased in size. Knowing that a supernova doesn't expand as quickly unless it just explodes, they explained that G1.9 should be a "very young" supernova - no more than 150 years old. But no information about a visible supernova has been found corresponding to this historical period (time Civil War in USA).

Spanish astronomers tracked this object with great interest because they were expecting its appearance. Gravity anomalies have been appearing in the Oort Cloud for some time, suggesting that disturbances were caused by a number of objects with significant mass. G1.9 was recorded to have increased in size even further. This is exactly what they expected, and it proves that an object (Planet X, Nibiru, Nemesis) has approached Earth.

Object G1.9 [top right] is currently positioned toward the center of our Galaxy, Sagittarius, which glows brightly in this infrared spectrum image. Due to the bright background, G1.9 is not visible in normal wavelengths of light.

The image [above] shows evidence that the object grew in size over a period of 23 years. On the left, a blue spherical object was detected in the radio range in 1985 by the Very Large Array. The image on the right shows the same observation point taken in 2008. Obviously the object is larger.

In this image [above] we see the original 1985 photo of the radio emission from the VLA compared to the 2007 photo, this X-ray image taken by the Chandra Observatory.

The image above was provided by the Starviewer team. It shows the object G1.9 on the left and the famous brown dwarf, Gilese 229A on the right. We look for emissions in the microwave range (Starviewer says) that indicate radiated heat from each source. The dark red area is the hottest. Note that the G1.9 has a solid heat output similar to the Gilese 229A. The Starviewer team says this suggests that if G1.9 is truly a supernova, as previously thought, we might expect the spherical region to be larger as hot gas and emissions from the exploding star would be concentrated in the surrounding body .

An example of an infrared scan of the Cygnus-Loop supernova ejecta is below.

There is scientific evidence that the G1.9 brown dwarf is the real cause of climate change. Back in July 2010, Dr. Paul Clark published articles on Science.com regarding this issue, and nearly 700 scientists signed a report on climate change.

StarViewer Team, published the results of her research back in 2009 in a number of journals, as well as on your website. The collected evidence met with an extremely negative reaction in astronomical circles, which in every possible way prevented the acceptance of the discovery and demanded more evidence.

In its statement, Starviewer wrote that NASA would never allow this information to be made public. NASA is fooling people, distracting their attention with all sorts of nonsense, while a small group of scientists is trying to tell the world what is happening and the reason for it.

In their article, Spanish astronomers openly accused NASA scientists of concealing information that there is another massive object in our solar system (twice the size of Jupiter) - a brown dwarf star (official name G1.9), which affects orbits of the planets known to us. That is, in essence, our Solar system is binary. Spanish astronomers claim that all this has long been known to NASA, which is simply leading everyone by the nose, hiding this information from ordinary people.

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 assumptions that may complement the generally accepted theory or are considered 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.

What an asteroid collision with Earth looked like

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 during that period two celestial bodies. 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 environment.

After the dinosaurs came the age of mammals

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