The origin of life on Earth occurred about 3.8 billion years ago, when education ended earth's crust. Scientists have found that the first living organisms appeared in aquatic environment, and only after a billion years did the first creatures come to the surface of the land.

The formation of terrestrial flora was facilitated by the formation of organs and tissues in plants, the ability to reproduce by spores. Animals also evolved significantly and adapted to life on land: internal fertilization, the ability to lay eggs, and pulmonary respiration appeared. An important milestone development was the formation of the brain, conditional and unconditioned reflexes, survival instincts. The further evolution of animals provided the basis for the formation of mankind.

The division of the history of the Earth into eras and periods gives an idea of ​​the features of the development of life on the planet in different time periods. Scientists identify particularly significant events in the formation of life on Earth in separate periods of time - eras, which are divided into periods.

There are five eras:

• Archean;
• Proterozoic;
• Paleozoic;
• Mesozoic;
• Cenozoic.

The Archean era began about 4.6 billion years ago, when the planet Earth only began to form and there were no signs of life on it. The air contained chlorine, ammonia, hydrogen, the temperature reached 80 °, the radiation level exceeded the permissible limits, under such conditions the origin of life was impossible.

It is believed that about 4 billion years ago our planet collided with celestial body, and the result was the formation of the Earth's satellite - the Moon. This event became significant in the development of life, stabilized the axis of rotation of the planet, contributed to the purification of water structures. As a result, the first life originated in the depths of the oceans and seas: protozoa, bacteria and cyanobacteria.

The Proterozoic era lasted from about 2.5 billion years to 540 million years ago. Remains of unicellular algae, mollusks, annelids. Soil is starting to form.

The air at the beginning of the era was not yet saturated with oxygen, but in the process of life, the bacteria that inhabit the seas began to release more and more O 2 into the atmosphere. When the amount of oxygen was at a stable level, many creatures took a step in evolution and switched to aerobic respiration.

Palaeozoic includes six periods.

Cambrian period(530 - 490 million years ago) is characterized by the emergence of representatives of all types of plants and animals. The oceans were inhabited by algae, arthropods, mollusks, and the first chordates (Haikouihthys) appeared. The land remained uninhabited. The temperature remained high.

Ordovician period(490 - 442 million years ago). The first settlements of lichens appeared on land, and the megalograpt (a representative of arthropods) began to come ashore to lay eggs. Vertebrates, corals, sponges continue to develop in the thickness of the ocean.

Silurian(442 - 418 million years ago). Plants come to land, and rudiments of lung tissue form in arthropods. The formation of the bone skeleton in vertebrates is completed, sensory organs appear. Mountain building is underway, different climatic zones are being formed.

Devonian(418 - 353 million years ago). The formation of the first forests, mainly ferns, is characteristic. Bone and cartilaginous organisms appear in water bodies, amphibians began to land on land, new organisms are formed - insects.

Carboniferous period(353 - 290 million years ago). The appearance of amphibians, the sinking of the continents, at the end of the period there was a significant cooling, which led to the extinction of many species.

Permian period(290 - 248 million years ago). The earth is inhabited by reptiles, therapsids appeared - the ancestors of mammals. Hot climate led to the formation of deserts, where only resistant ferns and some conifers could survive.

The Mesozoic era is divided into 3 periods:

Triassic(248 - 200 million years ago). The development of gymnosperms, the appearance of the first mammals. The division of land into continents.

Jurassic period(200 - 140 million years ago). Emergence angiosperms. The emergence of the ancestors of birds.

Cretaceous period(140 - 65 million years ago). Angiosperms (flowering) became the dominant group of plants. The development of higher mammals, real birds.

Cenozoic era consists of three periods:

Lower Tertiary period or Paleogene(65 - 24 million years ago). The disappearance of the majority cephalopods, lemurs and primates appear, later parapithecus and dryopithecus. Ancestor development modern species mammals - rhinos, pigs, rabbits, etc.

Upper Tertiary or Neogene(24 - 2.6 million years ago). Mammals inhabit land, water and air. The emergence of Australopithecus - the first ancestors of humans. During this period, the Alps, the Himalayas, the Andes were formed.

Quaternary or Anthropogene(2.6 million years ago - today). A significant event of the period is the appearance of man, first Neanderthals, and soon Homo sapiens. vegetable and animal world acquired modern features.

Scientists studying the ancient world argue that our ancestors lived much less than modern man. No wonder, because before there was no such developed medicine, there was no such knowledge in the field of our health that allows a person today to take care of himself and portend dangerous diseases.

However, there is another opinion that our ancestors, on the contrary, lived much longer than you and I. They ate organic food, used natural medicines (herbs, decoctions, ointments). And the atmosphere of our planet was much better than now.

The truth, as always, is somewhere in the middle. This article will help to better understand what was the life expectancy of people in different eras.

The ancient world and the first people

Science has proven that the first people appeared in Africa. Human communities did not appear immediately, but in the process of a long and painstaking formation of a special system of relationships, which today are called "public" or "social". Gradually, ancient people moved from place to place and occupied new territories of our planet. And around the end of the 4th millennium BC, the first civilizations began to appear. This moment became a turning point in the history of mankind.

The times of the primitive communal system so far occupy most of the history of our species. It was the era of the formation of man as a social being and as a biological species. It was during this period that the ways of communication and interaction were formed. Languages ​​and cultures were created. Man learned to think and make reasonable decisions. The first rudiments of medicine and healing appeared.

This primary knowledge has become a catalyst for the development of mankind, thanks to which we live in the world that we have now.

Anatomy of an ancient person

There is such a science - paleopathology. She studies the structure of ancient people from the remains found during archaeological excavations. And according to the data obtained during the study of these findings, scientists have found that ancient people got sick just like us, although before the advent of this science everything was completely different. Scientists believed that prehistoric man did not get sick at all and was completely healthy, and diseases appeared as a result of the emergence of civilization. Thanks to knowledge in this area, modern scientists have found that diseases appeared before man.

It turns out that our ancestors were also at risk from harmful bacteria and various diseases. According to the remains, it was determined that tuberculosis, caries, tumors and other diseases were not uncommon among ancient people.

Lifestyle of ancient people

But not only diseases created difficulties for our ancestors. Constant struggle for food, for territory with other tribes, non-observance of any hygiene rules. Only during the hunt for a mammoth from a group of 20 people could return about 5-6.

ancient man completely reliant on himself and his abilities. Every day he fought for survival. About mental development there was no talk. Ancestors hunted and defended the territory they inhabited.

Only later did people learn to pick berries, roots, grow some kind of crops. But from hunting and gathering to agricultural society that marked the beginning new era, humanity has been going on for a very long time.

The lifespan of a primitive man

But how did our ancestors cope with these diseases in the absence of any medicines or knowledge in the field of medicine? The very first people had a hard time. The maximum to which they lived was the age of 26-30 years. However, over time, a person has learned to adapt to certain environmental conditions, and to understand the nature of certain changes occurring in the body. Gradually, the life expectancy of ancient people began to increase. But this happened very slowly with the development of healing skills.

There are three stages in the formation of primitive medicine:

• Stage 1 - the formation of primitive communities. People were just beginning to accumulate knowledge and experience in the field of healing. They used animal fats, applied various herbs to wounds, prepared decoctions from ingredients that came to hand;
• Stage 2 - the development of the primitive community and the gradual transition to their disintegration. Ancient man learned to observe the processes of the course of the disease. I began to compare the changes that occurred in the process of healing. The first "medicines" appeared;
• Stage 3 - the collapse of primitive communities. At this stage of development, medical practice finally began to take shape. People have learned to treat certain ailments effective ways. We realized that death can be cheated and avoided. The first doctors appeared;

In ancient times, people died from the most insignificant diseases, which today do not cause any concern and are treated in one day. A man died in the prime of his life, not having time to live to old age. The average duration of a person in prehistoric times was extremely low. IN better side everything began to change in the Middle Ages, which will be discussed further.

Middle Ages

The first scourge of the Middle Ages is hunger and disease, which still migrated from ancient world. In the Middle Ages, people not only starved, but also satisfied their hunger with terrible food. Animals were killed on dirty farms in complete unsanitary conditions. There was no talk of sterile methods of preparation. In medieval Europe, the swine flu epidemic claimed tens of thousands of lives. In the 14th century, a plague pandemic that broke out in Asia wiped out a quarter of Europe's population.

Medieval lifestyle

What did people do in the Middle Ages? The eternal problems remain the same. Diseases, the struggle for food, for new territories, but to this was added more and more problems that a person had when he became more reasonable. Now people began to wage wars for ideology, for an idea, for religion. If earlier man fought with nature, now he fought with his fellows.

But along with this, many other problems also went away. Now people have learned how to make fire, build themselves reliable and durable dwellings began to observe the primitive rules of hygiene. Man learned to skillfully hunt, invented new methods to simplify everyday life.

Lifespan in Antiquity and the Middle Ages

The miserable state in which medicine was in ancient times and the Middle Ages, many diseases that were incurable at that time, poor and terrible food - all these are signs that characterize the early Middle Ages. And this is not to mention the constant strife between people, about the conduct of wars and crusades that took hundreds of thousands human lives. The average life expectancy still did not exceed 30-33 years. Forty-year-old men were already called "mature husband", and a man of fifty was even called "elderly". Residents of Europe in the 20th century lived up to 55 years.

IN Ancient Greece people did live an average of 29 years. This does not mean that in Greece a person lived to the age of twenty-nine and died, but this was considered old age. And this despite the fact that in those days the first so-called "hospitals" had already been formed in Greece.

The same can be said about Ancient Rome. Everyone knows about the powerful Roman soldiers who were in the service of the empire. If you look at the ancient frescoes, then in each of them you can recognize some god from Olympus. One immediately gets the impression that such a person will live long and remain healthy throughout his life. But the statistics say otherwise. Life expectancy in Rome was hardly 23 years old. The average duration throughout the Roman Empire was 32 years. So the Roman wars weren't all that healthy after all? Or are incurable diseases to blame for everything, from which no one was insured? It is difficult to answer this question, but data taken from more than 25,000 epitaphs on the tombstones of cemeteries in Rome speaks of such figures.

In the Egyptian empire, which existed even before the beginning of our era, which is the cradle of civilization, the SOL was no better. She was only 23 years old. What can we say about the less civilized states of antiquity, if life expectancy even in ancient egypt was negligible? It was in Egypt that people first learned to treat people with snake venom. Egypt was famous for its medicine. At that stage in the development of mankind, it was advanced.

Late Middle Ages

What about the later Middle Ages? In England, from the 16th to the 17th century, plague raged. Average life expectancy in the 17th century. was only 30 years old. In Holland and Germany in the 18th century, the situation was no better: people lived to an average of 31 years.

But life expectancy in the 19th century. began to increase slowly but surely. Russia XIX century was able to increase the figure to 34 years. In those days, in the same England, people lived less: only 32 years.

As a result, we can conclude that life expectancy in the Middle Ages remained at a low level and did not change over the centuries.

Modernity and our days

And only with the onset of the 20th century did humanity begin to equalize the indicators of average life expectancy. New technologies began to appear, people mastered new methods of curing diseases, the first medicines appeared in the form in which we are used to seeing them now. Life expectancy began to increase sharply in the middle of the twentieth century. Many countries began to develop rapidly and improve their economies, which made it possible to increase the standard of living of people. Infrastructure, medical equipment, everyday life, sanitary conditions, the emergence of more complex sciences. All this has led to a sharp improvement in the demographic situation throughout the planet.

The twentieth century heralded a new era in the development of mankind. It was truly a revolution in the world of medicine and in improving the quality of life of our species. For some half a century, life expectancy in Russia has almost doubled. From 34 years to 65. These figures are amazing, because for several millennia a person could not increase his life expectancy even by a couple of years.

But the sharp rise was followed by the same stagnation. From the middle of the twentieth century until the beginning of the twenty-first century, no discoveries were made that radically changed the idea of ​​\u200b\u200bmedicine. Certain discoveries were made, but this was not enough. Life expectancy on the planet has not increased as rapidly as it did in the middle of the 20th century.

XXI Century

The question of our connection with nature has sharply arisen before humanity. The ecological situation on the planet began to deteriorate sharply against the backdrop of the twentieth century. And many are divided into two camps. Some believe that new diseases appear due to our disregard for nature and environment, others, on the contrary, believe that the more we move away from nature, the more we prolong our stay in the world. Let's consider this question in more detail.

Of course, it is foolish to deny that without special achievements in the field of medicine, humanity would have remained at the same level of self-knowledge, its body at the same level as in the middle, and even later centuries. Now mankind has learned to treat such diseases that destroyed millions of people. Entire cities were taken away. Achievements in the field of various sciences such as: biology, chemistry, physics allow us to open new horizons in improving our quality of life. Unfortunately, progress requires sacrifice. And as we accumulate knowledge and improve technology, we inexorably destroy our nature.

Medicine and healthcare in the XXI century

But this is the price we pay for progress. Modern man lives many times longer than its distant ancestors. Today, medicine works wonders. We have learned how to transplant organs, rejuvenate the skin, delay the aging of body cells, and detect pathologies at the formation stage. And this is only a small part of what modern medicine can offer to everyone.

Doctors have been valued throughout human history. Tribes and communities with more experienced shamans and healers survived longer than others and were stronger. States in which medicine was developed suffered less from epidemics. And now those countries in which the healthcare system is developed, people can not only be treated for diseases, but also significantly prolong their lives.

Today, the vast majority of the world's population is free from the problems that people faced before. No need to hunt, no need to make fire, no need to be afraid of dying from a cold. Today man lives and accumulates wealth. Every day he does not survive, but makes his life more comfortable. He goes to work, rests on weekends, has a choice. He has all the means for self-development. People today eat and drink as much as they want. They do not need to worry about getting food when everything is in stores.

Life expectancy today

Average life expectancy today is approximately 83 years for women and 78 years for men. These figures do not go to any comparison with those that were in the Middle Ages and even more so in antiquity. Scientists say that biologically a person has been given about 120 years. So why are older people who turn 90 still considered centenarians?

It's all about our attitude to health and lifestyle. After all, the increase in the average life expectancy of a modern person is associated not only with the improvement of medicine. Here, the knowledge that we have about ourselves and the structure of the body also plays an important role. People have learned to follow the rules of hygiene and body care. A modern person who cares about his longevity, leads a correct and healthy lifestyle, does not abuse bad habits. He knows that it is better to live in places with a clean environment.

Statistics show that in different countries where the culture healthy lifestyle life is instilled in citizens from childhood, the mortality rate is much lower than in states where this is not given due attention.

The Japanese are the longest living nation. People in this country are accustomed to the right way of life from childhood. And how many examples of such countries: Sweden, Austria, China, Iceland, etc.

It took a long time for a person to reach such a level and life expectancy. He overcame all the trials that nature threw him. How much we suffered from illnesses, from cataclysms, from the awareness of the fate that is in store for all of us, but still we moved on. And we are still moving towards new achievements. Think about the path we've traveled through centuries of history of our ancestors and that their legacy should not go to waste, that we should only continue to improve the quality and length of our lives.

About life expectancy in different eras (video)

Palaeozoic.

This era, which began 570 million years ago. years ago, lasted 340 million years. Scientists divide it into six periods. Scientists divide it into six parts.

• 1. The earliest is the Cambrian (lasted 70 million years).
• 2. It was followed by the Ordovician (lasted 60 million years). The first round-mouthed - relatives - appear. They do not yet have jaws, but the structure of the mouth allows them to grab live prey, which is much more profitable than straining silt.
• 3. Silurian (30 million years), the first plants (psilophyte) come to land, covering the shores with a green carpet 25 cm high.
• 4. The next period is the Devonian (60 million years). The land is inhabited by club mosses, ferns, horsetails, mosses. The first insects already live in their thickets.
• 5. The next period is the Carboniferous, or Stone Age (65 million years). In the first vast expanses of land, swampy forests of tree-like ferns, horsetails and club mosses were covered.
• 6. The last period of the era - Perm, or the Permian period (55 million). The climate became cold and drier. wet forests from ferns and club mosses have disappeared.

The era of middle life (Mesozoic).

The Mesozoic era began 230 million years ago and lasted 163 million years. It is divided into three periods: Triassic (35 million years), Jurassic, or Jurassic period (58 million years), and Cretaceous, or Cretaceous period (70 million years).

In the seas, even in the Permian period, trilobites finally died out. But this was not the sunset of the marine invertebrates. On the contrary: each extinct form was replaced by several new ones. During mesozoic era Earth's oceans abounded with mollusks: squid-like belemnites (their fossil shells are called "devil's fingers") and ammonites. The shells of some ammonites reached 3m. In diameter. No one else on our planet, either before or later, had such colossal shells!

The Mesozoic, especially the Jurassic, can be called the kingdom of reptiles. But even at the very beginning of the Mesozoic, when the reptiles were just moving towards their dominance, small, furry, warm-blooded mammals appeared next to them. For a long 100 million years they lived next to the dinosaurs, almost invisible against their background, patiently waiting in the wings.

In the Jurassic, dinosaurs also had other warm-blooded rivals - the first birds (Archaeopteryx). They had a lot more in common with reptiles: for example, jaws dotted with sharp teeth. In the Cretaceous period, real birds also descended from them.

At the end Cretaceous The Earth's climate has become colder. Nature could no longer feed animals weighing more than ten kilograms. A mass extinction began (stretching, however, for millions of years) of dinosaur giants. Now the vacated place could be occupied by animals and birds.

The Triassic weakens
climatic zoning, smoothing
temperature differences Start of movement
continents. Gigantic die out
ferns, tree-like horsetails, club mosses.
Gymnosperms are flourishing.
The emergence of the first bony fish. in the triassic
started Great War two land
tribes - reptiles and animal-like.
Phytosaurus

The World of the Early Triassic 250 million years ago, all the land of the Earth was united into the supercontinent Pangea, located in one

hemisphere.
The climate at that time was almost the same everywhere, without
such fluctuations in temperature as in the modern world.
The area of ​​land that has become Africa in our time,
surrounded both Americas (from the west), Europe (from the north) and
Antarctica (from the south). Modern Asian peninsula
Hindustan was a single whole with Africa, separated
from Asia by a huge bay.

The shallow lagoons of the Triassic seas were home to a variety of marine reptiles, including Askeptosaurus (above),

reminiscent of today's crocodiles, and Placodus, which reached 2.5
m in length and fed on shellfish.

The first mammals evolved from animal-like lizards

Aromorphoses of mammals:
four-chambered heart, loss of the right
aortic arches;
warm-bloodedness;
prolonged gestation of young
mother's body, nutrition of embryos through
placenta;
more developed brain
activity

Aromorphoses of mammals: (continued)

limbs under the body;
perfect lungs;
outer ear;
sweat glands;
differentiated teeth;
diaphragm;
feeding babies with milk;
hair cover.

Plants,
prevailing in
landscapes
triassic period,
included
treelike
ferns (top)
left), cycad (in
center) and horsetail
(right), arising from
the Paleozoic era.
petrified
ferns (lower
figure) were
found in rocks
Antarctica.

10. 220 million years ago, the landscape was dominated by shrubs interspersed with coniferous trees resembling modern ones, and huge

ginkgo plants (on the lower
the figure shows their fossilized leaves).

11.

The first gymnosperms appeared in
end of the Paleozoic. In the Mesozoic they changed
tree ferns and horsetails, which in
drier
climate.
Encephalarthos, cycad tree

12. Ginkgo

Ginkgo (Ginkgo biloba), the only one
a preserved species of the extensive order Ginkgoaceae,
flourished during the Mesozoic era.

13. Oppressive

GREAT (Gnetales; gnetophytes, Gnetophyta),
order (according to other representations, superorder
or class) of extinct and living relict
gymnosperms
Velvichia
Gnetum

14. Conifers

CONIFEROUS, a class of gymnosperms.
Currently widely distributed.
Mostly evergreen trees and
shrubs, usually with acicular (needles)
or scaly leaves and unisexual
strobili (cones). OK. 50 births, ca. 600
types. Many conifers (pine, spruce,
larch, fir, etc.) - valuable
forest species.

15.

In the Jurassic period, the climate, initially humid, in
end dry. There's a movement
continents, the formation of the Atlantic
ocean. The emergence of new groups of mollusks.
The seed ferns are dying out and
first angiosperms appear
plants. Insects flourish and
reptiles. At the end of the period, the appearance
the first bird, Archeopteryx.

16. Asteroceras obtusum - one of the ammonite species that lived in the seas of the Jurassic period. At that time their shells were covered much

more intricate
than the earlier species
patterns.
some shells
grew to three or more
meters.
ate big fish And
were dangerous predators

17. Development of mammals

dimetrodon
megaastrodon
lycanops trinadoxone
the first warm-blooded and viviparous mammals,
similar to modern ones appeared at the beginning of the Jurassic
more than 180 million years ago

18. The middle of the era of dinosaurs (Jurassic period).

Dinosaurs flourished during the Jurassic period
(208-144 million years ago). It is named so because
that in the Jura mountains, located on the territory
France and Sweden, there are stones that
formed at this time.
Some of the dinosaurs of this period were
of impressive size, armed with plates and
spikes.
Among
them
meet:
allosaurus,
Archeopteryx, Brachiosaurus, Diplodocus, Stegosaurus and
other.

19. Allosaurus

Meaning
titles:
"Strange Lizard"
Size: 11m long
Weight: 1.5 tons
Other data:
moved on two
legs, thick neck,
small but
strong upper
limbs, claws
top fingers and
lower
limbs, huge
teeth, strong legs,
strong tail, open in
USA
in 1869

20. Stegosaurus

Name meaning: "Roofing
pangolin"
Size: 9m long
Weight: 6-8 tons
Other information: traveled
four legs, small head,
tiny brain, double on the back
row of plates, spiked tail,
toothless beak-shaped mouth, small
molars, opened in the USA in
1877
Stegosaurus

21. Dinosaurs dominated land, water and air

Development
reptiles went
along the way
idioadaptations

22. One of the largest herbivorous dinosaurs of the Jurassic period - diplodocus (Diplodocus). The long neck allowed him to "comb" food

One of the biggest
herbivorous dinosaurs
jurassic diplodocus (Diplodocus).
Long neck allowed
him to "comb" food from
the tallest conifers
plants. It is believed that
diplodocus lived
small herds and
fed on shoots
trees.

23. Diplodocus holds an important place in the imagination of many British schoolchildren because of this impressive skeleton displayed in

London Natural History Museum (nearby is the skeleton
Triceratops).

24. DISCOVERY OF ARCHEOPTERYX

The remains of Archeopteryx have been found in
fine-grained limestones of southern Germany,
which in the 19th century widely used in
printing lithographs. When in 1860 the workers
quarry split one of the limestone slabs,
then they found in the thickness of the layers the skeleton of a creature,
resembling a bird. These remains were
researched and described by the German
paleontologist Hermann Mayer in 1861,
who named the found creature Archaeopteryx
lithographica.

25. The fossilized bones of Archeopteryx (top picture) allowed paleontologists to solve the problem of the appearance of this unusual bird.

(round inset): this color scheme is only an assumption, but physical
the outlines are scientifically proven.

26. Aromorphoses of birds

four-chambered heart, loss of one of
two aortic arches (left);
warm-bloodedness;
greater brain development and more
complex behavior;
care for offspring.

27.

Cool climate during the Cretaceous
an increase in the area of ​​the oceans and
new land uplift. Go intense
mountain building processes (Alps,
Andes, Himalayas). Parallel begins
evolution of flowering plants and insect pollinators. Carnivorous dinosaurs are dying out
and large reptiles. In the seas are dying
many forms of invertebrates and marine
lizards. Fittest
are birds and mammals.

28. This is how the plain of modern Northwestern Europe could look like at the beginning of the Cretaceous period. Dinosaur in the background - herbivore

reptile, iguanodon (Iguanodon). In the foreground are turtles and
crocodiles similar to modern ones.

29. The number and species diversity of mammals increased, animals appeared, the descendants of which are associated primarily with

one continent -
Australia. These are marsupials, the most primitive of the present
living viviparous mammals and monotremes
(cloacal), or oviparous mammals.
Echidna from Australia is a representative of an unusual
groups of single pass (or
cloacal) mammals.
Like reptiles, these
mammals
lay eggs.
Similar animals lived in
Australia is already 65 million years old
back.

30. During the transition from the early to the middle Cretaceous, the first flowering plants appeared. At the same time, the evolution

huge herbivores
dinosaurs
petrified leaf
magnolias (bottom)
found in rocks
Upper Cretaceous
period in Saxony
(Germany).
Reconstruction
plants (left)
shows that it
very much like
Magnolia grandiflora,
favorite
gardeners.

31. Aromorphoses of flowering plants

flower appearance and rise
pollination efficiency by different
ways;
double fertilization;
the ovule is hidden inside the ovary and
protected from external influences;
seeds develop inside the fruit;
the greatest degree of differentiation
vegetative body.

32. Tyrannosaurus overtaking prey. The largest of the terrestrial predators, it reached 13 m in length and towered 5 m above the ground.

Their short front
limbs he probably
used for
to rise from
lying position.
Remains of a tyrannosaurus rex
discovered in the USA.
Similar creatures lived
also on the territory
Canada and China.

33. By the end of the Cretaceous period, the animal world of the land had reached a great diversity, and its representatives were perfectly adapted to

life in an even
And favorable climate this era. However
disaster was just around the corner
Ankylosaurs of two types:
Euoplocephalus with
clubbed tail and
studded with thorns
Edmontia. These herbivores
lizards could successfully
defend against predators
dinosaurs.

34. DEATH OF THE DINOSAURS One of the most significant events in the history of the Earth occurred ca. 65 million years ago. Died out at this time

some
large groups of vertebrates
including dinosaurs as well
marine (mosasaurs,
plesiosaurs, pliosaurs and
ichthyosaurs) and flying
(pterosaurs) reptiles.
Other vertebrates: frogs,
lizards, crocodiles, snakes,
turtles, mammals and
survived the disaster.

35. conclusion

ANCIENTITY OF THE MESOZOIC ERA - 230 MILLION B.C. YEARS,
DURATION - 165 MILLION YEARS;
IN THE MESOSOIC, REPTILES ACHIEVE HUGE
DIVERSITY FROM ANCIENT TRIASSIC REPTILES TO OURS
DAYS LIVED TURTLES AND TUTTERS;
AFTER THE GREAT FLOWERING OF THE DINOSAURS, THEM COMED
RAPID EXTINCTION;
MAMMALS HAVE BEEN REPLACED, IN THE SECOND
HALF OF THE CRETATS HAVE ARISED MASSUPATES AND PLACENTALS;
THE FIRST BIRDS APPEARED IN THE JURASSIC PERIOD;
IN THE CRETACEETIC PERIOD THE FIRST FLOWERS APPEARED
PLANTS.