How do we know about the existence of dinosaurs if no one has ever seen them? Thanks to the discovery of many fossil skeletons.

From them you can understand how dinosaurs were structured and how these ancient reptiles lived.

Imprints in the rocks

By studying fossil remains in rocks, scientists have discovered many interesting things. For example, they found that the first living creatures appeared in the sea over 3 billion years ago.

Restoring the skeleton - the work of a paleontologist

Scientists who study prehistoric animals are called paleontologists. They are the ones who search for fossilized bones on all continents. The bones, carefully cleared of layers, are cataloged and then sent to laboratories where skeletons are recreated from them. If individual parts are missing, they are replaced with copies molded from plaster or plastic.

Here is a restored Triceratops skeleton in a paleontological museum. Now anyone can see how big and strong he was. From the teeth we can understand what he ate, and from the size of the bones we can draw conclusions about his weight, method of movement, and even lack of dexterity.

Municipal Budgetary Educational Institution "General Educational School No. 35" of the Kiselevsky Urban District

The work was completed by: Evgeniy Tarasov, student of class 2 “B” of Municipal Budgetary Educational Institution “Secondary School No. 35” of the Kiselevsky Urban District

Head: Natalya Vladimirovna Dontsova, teacher of Municipal Budgetary Educational Institution “Secondary School No. 35” of Kiselevsky Urban District

2015

Introduction

1. Relevance of the problem

   Purpose of the study

   Research objectives

   Research hypothesis

   Research methods

   Work plan

Research results

1. Before the dinosaurs

   Who are dinosaurs

   How we learned about dinosaurs

   Who named the dinosaurs

   Types of dinosaurs

   How did dinosaurs reproduce?

   Disappearance of the Dinosaurs

Conclusion

Literature

Chapter 1. Introduction

1.1 Research problem and its relevance

I wanted to learn as much as possible about the planet's past. One of the most mysterious periods for researchers is the era of dinosaurs - the largest creatures that ever existed on this planet.

Many years have passed since the first fossilized remains of dinosaurs were discovered.What reason caused the mass death of these giants, who dominated the Earth for about one hundred and forty million years? Was it allowed?scientiststhis riddle? I decided to find an answer to this question

This is how the topic of my research appeared “Dinosaurs and their extinction».

1.2 Purpose of the study:
studying the theory of the appearance of dinosaurs, hypotheses about their disappearance

1.3 Research objectives:

1. collect information about the origin of dinosaurs;

2. get acquainted with their most prominent representatives;

3. explore and analyze hypotheses about the extinction of dinosaurs;

Object of study : varieties of dinosaurs.
Subject of study: life of dinosaurs on planet Earth.

1.4 Research hypothesis:

dinosaurs became extinct due to a global catastrophe.

1.5 Research methods:

access to encyclopedic dictionaries, deduction, comparison, generalization.

1.6 Work plan

1. Find out who dinosaurs are.

2. Find out how they lived and what they ate.

3. Find out how people learned about dinosaurs.

4. Find out what they looked like and why they disappeared.

Chapter 2. Research results

2.1 Before the dinosaurs

Life on Earth appeared 4.6 billion years ago. Its long history is divided into several periods, during which an amazing variety of living organisms appeared and died out. At first, warm seas covered most of the Earth, and single-celled bacteria, including blue-green algae, appeared there. In the Paleozoic era, more complex plants and animals appeared in the seas - worms, jellyfish, and mollusks, which flourished in the warm seas and served as prey for fish. In the first half of the Paleozoic, plants and animals populated the land. Amphibians evolved from lobe-finned fish, among which were both predators and vegetarians. Amphibians gave rise to reptiles that were able to reproduce outside of water. Ancient reptiles became the ancestors of turtles, lizards, crocodiles, dinosaurs and mammals. Dinosaurs have been the rulers of the world for many millions of years.

2.2 Who are dinosaurs?

Dinosaurs were very special reptiles. The first dinosaurs appeared approximately 230 million years BC. "Dinosaur" means "terrible lizard". Some were the size of chickens, others the size of airliners. These creatures have achieved the greatest success of all the animals on Earth. They dominated for about 150 million years during the Mesozoic era, populating all continents. The Mesozoic era is divided into the Triassic, Jurassic and Cretaceous periods. Like modern reptiles, dinosaurs had scaly skin and laid eggs. The first dinosaurs were carnivores; herbivores appeared later. Dinosaurs are divided into two orders: saurian and ornithischian, depending on the structure of the pelvic bones. They and their ancestors, the trackodonts, were the only reptiles whose legs were located directly under the body. Modern reptiles have legs spread apart.

When it comes to dinosaurs, our imagination paints grandiose pictures. I learned that dinosaurs ruled the water, land and sky, and were herbivores and predators. Bloodthirsty tyrannosaurs, peace-loving giants diplodocus, winged pterosaurs and giant inhabitants of the deep sea - pliosaurs.

Although we usually think of dinosaurs as one group of animals, they can actually be clearly divided into two types.

The first group included lizard-breeds, which included “beast-footed” (carnivorous theropods) and huge “lizard-footed” (herbivorous sauropods)

Herbivorous sauropod Carnivorous theropod

The second order includes ornithischian dinosaurs. Most herbivorous dinosaurs were ornithischians.

2.3 How did we learn about dinosaurs?

Everything that is known today about dinosaurs has been learned by people by examining fossils of plants, animals, or their parts—in other words, fossils—that are found during excavations or by accident.

Some places where dinosaur remains were found are called “burials” or “burial grounds” because a huge number of bones, including entire skeletons, were found there.Of course, remains can be discovered completely by accident, but in most cases, an expedition of paleontologists (scientists who excavate extinct plants and animals) arrives at a certain place and begins to look for pieces of bones in the ground. Theystumble upon a pile of petrified bones. Scientists are studying such findings in detail. They have to collect information bit by bit, recreate the conditions of the primitive world from fossils.

Quite a lot is known about where dinosaurs lived. Dinosaur fossils are found in rocks, and these rocks themselves can tell us what the climate was like - hot or cold, rainy or dry, how far it was from the sea, what plants looked like and what other animals lived at that time. Scientists obtain this information by studying the geological structure of places where dinosaur remains are found, i.e. all this can be learned from the rocks. For example, geologists who find cracked pieces of clay next to the skeleton of a dinosaur understand that there was once a dry reservoir there.

2.4 Who named the dinosaurs?

The English scientist Richard Owen (1804–1892) found a large number of huge bones. The animals whose skeletons he discovered seemed very scary to him, and he called them “terrible lizards,” or dinosaurs. Since then they have been called that.

2.5 Types of dinosaurs

800 is the number of dinosaurs known to science. Here are the most amazing among them.

1. Ouranosaurus – herbivorous, length 9 meters, weight 2 tons. The dorsal ridge regulates body temperature.

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2.Triceratops – herbivorous, length 9 meters, weight 6 tons.

3. Brachiosaurus – herbivorous, length 23 meters, weight 50 tons. With the help of its long neck it could eat leaves from tall trees.

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4. Compsognathus – predator, length 60 cm, weight 2-3 kg. One of the smallest dinosaurs.

Carnivorous, or carnivorous, dinosaurs were powerful animals. They walked upright on their hind legs,and their forelimbs were much shorter and ended in clawed fingers.

Allosaurus - "strange lizard", "different lizard"

Length - 11-12 m, height - up to 4.5 m, weight - 1.5-2 t

Tyrannosaurus

Tyrannosaurus was one of the largest land predatory dinosaurs

ever living on our planet.

Business cardthisdinosaur is the power of his jaws. In terms of bite force, he had no equal.

Large carnivores, such as Gigantosaurus or Tyrannosaurus, had a huge head on a short neck and very strong, sharp teeth the length of a human arm.

Almost all predatory reptiles had a massive tail extended back, which helped maintain balance when running.

2.6 How dinosaurs reproduced

I decided to find out how dinosaurs reproduced?

I read in a book that thanks to excavations, people learned that dinosaurs laid eggs. As it turned out, some of the fossilized eggs even contained embryos.

2.7 Disappearance of dinosaurs

Dinosaurs began to die out approximately 65 million years ago. At the same time, huge aquatic and flying reptiles disappeared. Why did this happen? Probably, sudden changes in environmental conditions led to climate fluctuations and changes in vegetation. Herbivores died and carnivores were left without food. There are several hypotheses. Some scientists link the extinction of dinosaurs

Firstly: with the fall of a huge meteorite to Earth.

65 million years ago, a giant meteorite fell to Earth, causing fires everywhere and raising huge clouds of dust into the air, obscuring the Sun and plunging our planet into cold and darkness. This killed many species of plants - the main food of dinosaurs. Only small creatures, mammals and birds, were able to survive in such terrible conditions. As a result, dinosaurs disappeared, and with them all flying and most marine reptiles.

Secondly : with volcanic eruption

The accumulation of ash in the atmosphere changed the climate, the air became unsuitable for breathing due to the abundance of toxic gases.

Third : with climate cooling

The separation of Antarctica and Australia led to a cooling of warm waters and provoked a sharp climate change with large temperature jumps, especially on the continents. This hypothesis is the least reliable.

Chapter 3. Conclusion

At the conclusion of my work, I concluded that dinosaurs became extinct, but, apparently, not without a trace. For example, there are many similarities between dinosaurs and birds. Today, many paleontologists believe that dinosaurs were the ancestors of birds. The skeleton of Archeopteryx, the first known bird, was very similar to the skeleton of the predatory lizard-hipped dinosaur Compsognathus. Many scientists consider Archeopteryx to be a small carnivorous dinosaur with feathers. Dinosaurs are also related to crocodiles, which survived the great extinction at the end of the Cretaceous period. Crocodiles and dinosaurs were very similar, they had common ancestors - thecodonts. Dinosaurs disappeared, and their “brothers” today differ little from their ancestors. Their way of life has hardly changed in 150 million years.

Hard work to find and study new and previously found remains allows scientists to move forward, partially lifting the veil of secrecy, confirm or refute various hypotheses. Each additional drop of information gained from research can significantly influence existing views.

I discovered the secret of centuries gone by, I learned how and when dinosaurs appeared. My virtual journey into their unknown world, which still holds many mysteries and secrets, has ended. I hope that you have expanded your knowledge and want to learn even more. Thank you for your attention!

Literature

M. Avdonina, “Dinosaurs”. Complete encyclopedia, M.: Eksmo, 2007.

L. Cambournac, “Dinosaurs”. Children's Encyclopedia, M, "Swallowtail", 2006.

K. Clark, "These Amazing Dinosaurs and Other Prehistoric

animals", Publishing house "Makhaon", 1998.

When the dinosaur bone was first described in 1676, it was thought to belong to an elephant or perhaps some kind of giant. More than a century later, scientists realized that such fossils were the remains of creatures called megalosaurs. They were depicted as stocky, overgrown lizards. Then, in 1842, leading anatomist Richard Owen recognized megalosaurs as part of a whole new group of animals, which he called dinosaurs, i.e., "terrible lizards."

Since then, nearly 700 different species of dinosaurs have been described, with new ones being discovered every month. Our ideas about them have also changed radically. The dinosaurs we know today are very different from the ones you read about in books as a child.

Myth #1: All dinosaurs were big

The word "dinosaur" tends to conjure up images of a giant, and of course many of them were really big. Tyrannosaurus, for example, reached 12 meters in length and weighed 5 tons. Most likely, he was not even the largest of the carnivores. But herbivorous sauropods grew to titanic sizes. The huge Argentinosaurus is known only from a few bones found, but its size is estimated to be up to 30 meters long and weigh 80 tons. It was larger than any mammal on earth, with the possible exception of some whales. But dinosaurs were truly unique. No other group of land animals before or after them was able to reach such sizes.

But not all dinosaurs were giants. The horned dinosaur Protoceratops was the size of a sheep. Velociraptor reached the size of a golden retriever. In the famous film "Jurassic Park" they were created much larger to make the plot more terrifying. In recent years, many small species have been discovered, no larger than a cat, rabbit or quail. These small species were probably more common than the giants. Most likely, the fact is that the massive bones of the Tyrannosaurus rex are better preserved and easier to detect.

Myth #2: All dinosaurs were scaly

When dinosaurs were first discovered, it seemed obvious that they were somehow related to crocodiles and lizards, and therefore must be scaly. And many dinosaurs did live up to this idea. But in the 1970s, paleontologists suggested that some of them might have been feathered, like their avian relatives.

Although it was considered a fake at the time, a small carnivorous dinosaur was discovered in 1997 that was not covered in scales. Since then, feathers have been found on herbivorous ornithopods, fanged generalodontosaurs, and many carnivorous species, including tyrannosaurids. This means that the T-Rex was most likely covered in feathers rather than scales.

Myth #3: All dinosaurs were green or brown

Early ideas about dinosaurs were based on monochromatic coloring, which included depressing shades of gray, green and brown. If the Mesozoic era really was that boring, it's no wonder everyone died out. But in reality their color was brighter, even garish. Researchers have identified traces of melanin on dinosaur feathers. The same pigment gives color to scales, bird feathers and our hair. Analyzes show that dinosaurs had a variety of colors, including black, white and ginger. Some ornithopods even boasted an iridescent sheen to their feathers.

In addition, some dinosaurs had patterns consisting of spots and stripes, light bellies and dark backs. This coloration probably served as camouflage to help dinosaurs hide from predators or prey. But bright colors and noticeable patterns could also serve to attract the attention of the opposite sex.

Myth #4: Dinosaurs were bad parents

Most reptiles simply bury their eggs and move on, preferring to let the offspring fend for themselves. However, this behavior is very risky. A sea turtle, for example, must lay thousands of eggs so that only a few can survive. Previously, scientists believed that dinosaurs used the same principle of dealing with offspring. But now we know that these are myths.

Dinosaurs' living relatives, birds and crocodiles, guard both eggs and young. This suggests that dinosaurs did the same. And now there is evidence. During an expedition in the Gobi Desert, scientists found a dinosaur on top of a clutch of eggs. It was assumed that he died during the attack on the nest. This species was called oviraptor, that is, “one who steals eggs.” However, several more skeletons were later found on top of the clutch of eggs. It turned out that the oviraptor did not eat the eggs, he guarded them.

Myth #5: Dinosaurs were doomed to extinction

The extinction of dinosaurs has long been attributed to their inability to adapt to changing conditions. In fact, they lived for over 100 million years, and their remains have been found in North and South America, Asia, Europe, Africa and Antarctica.

Although some argue that their species was in decline, fossils show that dinosaurs remained widespread and diverse until 66 million years ago, when an asteroid hit Earth (in what is now Mexico). Debris from the collision rose into the sky and blotted out the sun, plunging the world into darkness. The extinction of the dinosaurs was not nature's deliberate plan. It became a cosmic accident. If the asteroid had moved just a fraction of a degree, dinosaurs, not humans, would still rule the planet.

Myth #6: All dinosaurs went extinct

The asteroid destroyed many species of dinosaurs, and the rest disappeared later. But some small, feathered dinosaurs may have survived. They were direct descendants of their carnivorous cousins. These feathered relatives not only survived, but thrived, evolving into tens of thousands of bird species.

The word “dinosaur,” which translates as “terrible lizard,” appeared in 1842, when humanity was just trying to figure out what kind of bones were being discovered during excavations. It was then that the science of paleontology was born. The history of dinosaurs has since been rewritten several times, and at the moment there are many versions about their origin, formation and extinction. Let's consider the most common and relatively official option.

The birth of dinosaurs

Attempts to explain in simple language the history of dinosaurs in a film or cartoon have been made more than once, but the events that preceded their appearance on our planet were practically not covered anywhere. As you know, the ancestors of these creatures are reptiles and birds. In particular, crocodiles existing at the moment have the most similar features to ancient monsters. About 300 million years ago, when lizards in our familiar form already existed, a serious changing of the climate. The rainforests were largely destroyed, and the remnants of life huddled in the remaining small enclaves. This gave the first impetus to the enormous diversity of species, as each population developed independently of each other and tried to adapt to the conditions in which it existed. And they differed greatly in different regions. This is how the ancestors of dinosaurs appeared, scientists called archosaurs.

First types

The history of dinosaurs, at least in the form in which modern man imagines them, began approximately 200-245 million years ago. There is practically no exact data about the features and differences of these creatures in comparison with later samples, but one thing can be stated for sure:

• They were bipedal (dinosaurs with four legs appeared a little later, although the reverse situation would have seemed logical).
• The creatures were quite large, mostly reaching 2-4 meters in height.
• They were all cold-blooded. Because of this, the need for food, despite its impressive size, was not too great.
• At the initial stages of development, most likely, there were no flying species of these dinosaurs.

In general, humanity knows very little about this period. Most of the information is guesswork and theories based on various findings and indirect data. So things could have been completely different.

The Last Dinosaurs

The size of the “terrible lizards” gradually increased, and this continued until approximately the end of the Jurassic period (this was about 145 million years ago). In the middle of their life cycle, dinosaurs reached enormous sizes (up to 12 meters in height and 1 ton of net weight). During the “reign” of these monsters, no other species could simply even conditionally lay claim to dominance on the planet. Even later, in the Cretaceous period (65 million years ago), creatures began to become smaller. According to some reports, they developed the rudiments of feathers, and even warm-blooded species arose. Based on available information, the number of predators has decreased significantly, and, accordingly, the number of herbivores has increased. As a result, rare hunters have truly become real “killing machines.” They moved quickly, could cope with most opponents, had no shortage of food and were rightly considered at that time the pinnacle of evolution.

Mass extinction

The situation with the disappearance of this type of living creatures is well shown in the cartoon “The History of Dinosaurs.” Of course, the information there is more aimed at children, but active volcanoes, drought, lack of food and other similar problems could really cause the complete extinction of the prehistoric rulers of the planet. According to the official version, it all started with a huge meteorite that fell somewhere in the region of what is now Mexico. Upon impact, a large amount of dust rose into the atmosphere, sharply reducing the temperature on the surface (a similar situation is called “nuclear winter” and could become a reality if countries try to solve their problems with nuclear weapons). Along the way, the impact on the Earth activated dormant volcanoes. As a result, the simultaneous impact of several factors at once led to the fact that dinosaurs simply did not have time to adapt and, within a short period, almost completely died out. Most likely, some individuals remained, but they could not survive in the new world, in which other dominant species appeared. Many people think that this particular dinosaur story is for children. Allegedly, in reality everything was completely different. Unfortunately, in the future, scientists disagree in their opinions, and no one can yet come up with a clear theory about how everything really happened.

A lot of intriguing and mysterious things are shown in the “History of Dinosaurs” documentaries from popular science channels. True, they cannot be called documentary, since there are no documents, but everything there was reconstructed very competently. Nevertheless, every year more and more discoveries are made that radically change the understanding of dinosaurs as such. Let's see what interesting facts the modern history of dinosaurs reveals to us.

• Despite the fact that dinosaurs were considered to be almost a mistake of nature (too small a brain, too much weight, a strictly limited diet, etc.), they managed to dominate the planet for more than 130 million years. The history of man as such, if we take our more or less intelligent ancestors, at best, dates back 100 thousand years. So it is not a fact that in the distant future some new species will not be considered a mistake by modern humans.
• Tyrannosaurus, known in many films and literature as the most terrible and huge dinosaur, in fact was not one. There were even larger creatures, however, unlike this predator, they were still not hunters.
• The history of dinosaurs is still silent about why the tyrannosaurus even needs its small arms. Judging by the structure of the skeleton, he simply could not reach them anywhere. What makes it even more mysterious is the fact that these arms had very well developed muscles.
• Stegosaurus plates were used primarily not for protection from predators, but for heat dissipation. That is, they played the role of a natural radiator, in one case cooling a huge dinosaur, and in another helping it more efficiently accumulate heat, which is extremely important for any cold-blooded creature.

Results

The history of dinosaurs is gradually acquiring new data, some of which contradict each other or do not fit into existing theories. For example, it is believed that dinosaurs and people could not have existed in the same period of history. Although there are very interesting finds - stones on which ancient people quite reliably depicted the interaction between man and the “terrible lizard”. So far no one can say how everything really happened. We are not able to fully understand even our own history, let alone what happened long before the appearance of man as such.