Flora and fauna of the Mesozoic era. Brief information about the Mesozoic era

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general information

The Mesozoic era lasted approximately 160 million years.

years. It is usually divided into three periods: Triassic, Jurassic and Cretaceous; the first two periods were much shorter than the third, which lasted 71 million years.

In biological terms, the Mesozoic was a time of transition from old, primitive to new, progressive forms. Neither four-beam corals (rugoses), nor trilobites, nor graptolites crossed that invisible boundary that lay between the Paleozoic and Mesozoic.

The Mesozoic world was much more diverse than the Paleozoic, fauna and flora appeared in it in a significantly updated composition.

2. Triassic period

Periodization: from 248 to 213 million years ago.

The Triassic period in the history of the Earth marked the beginning mesozoic era, or era " average life". Before him, all the continents were merged into a single giant supercontinent Panagea. With the onset of Trias, Pangea again began to split into Gondwana and Laurasia, and the Atlantic Ocean began to form.

Sea levels around the world were very low. The climate, almost universally warm, gradually became drier, and vast deserts formed in the inland regions. Small seas and lakes evaporated intensively, because of which the water in them became very salty.

Animal world.

Dinosaurs and other reptiles have become the dominant group of land animals. The first frogs appeared, and a little later land and sea turtles and crocodiles. The first mammals also arose, and the variety of mollusks increased.

New species of corals, shrimp and lobsters have formed. By the end of the period, almost all ammonites had become extinct. Marine reptiles, such as ichthyosaurs, established themselves in the oceans, and pterosaurs began to master the air environment.

The largest aromorphosis: the appearance of a four-chambered heart, complete separation of arterial and venous blood, warm-bloodedness, mammary glands.

Vegetable world.

Below was a carpet of clubmosses and horsetails, as well as palm-like bennettites.

Fauna and flora in the Mesozoic. The development of life in the Triassic, Jurassic and Cretaceous periods

Jurassic period

Periodization: from 213 to 144 million years ago.

Back to top jurassic the giant supercontinent Pangea was in the process of active decay. South of the equator, there was still a single vast mainland, which was again called Gondwana. Later, it also split into parts that formed today's Australia, India, Africa and South America.

The sea flooded a significant part of the land. There was intense mountain building. At the beginning of the period, the climate was everywhere warm and dry, then it became more humid.

Terrestrial animals of the northern hemisphere could no longer move freely from one continent to another, but they still spread freely throughout the southern supercontinent.

Animal world.

The abundance and diversity of sea turtles and crocodiles has increased, and new species of plesiosaurs and ichthyosaurs have appeared.

The land was dominated by insects, the forerunners of modern flies, wasps, earwigs, ants and bees. The first Archeopteryx bird appeared. Dinosaurs dominated, evolving into many forms, from giant sauropods to smaller, swifter predators.

Vegetable world.

The climate became more humid, and all the land was overgrown with abundant vegetation. The forerunners of today's cypresses, pines and mammoth trees appeared in the forests.

The largest aromorphoses were not revealed.

Cretaceous period

Mesozoic Biological Triassic Jurassic

Periodization: from 144 to 65 million years ago.

During the Cretaceous period, the "great split" of the continents continued on our planet. The huge land masses that formed Laurasia and Gondwana gradually fell apart. South America and Africa were moving away from each other, and the Atlantic Ocean was getting wider and wider. Africa, India and Australia also began to move apart, and giant islands eventually formed south of the equator.

Most of the territory of modern Europe was then under water.

The sea flooded vast areas of land.

The remains of hard-covering planktonic organisms formed huge strata of Cretaceous deposits on the ocean floor. At first, the climate was warm and humid, but then it became noticeably colder.

Animal world.

In the seas, the number of belemnites has increased.

The oceans were dominated by giant sea turtles and predatory marine reptiles. Snakes appeared on land, and new varieties of dinosaurs arose, as well as insects such as moths and butterflies. At the end of the period, another mass extinction led to the disappearance of ammonites, ichthyosaurs and many other groups of marine animals, and all dinosaurs and pterosaurs died out on land.

The largest aromorphosis is the appearance of the uterus and intrauterine development of the fetus.

Vegetable world.

The first flowering plants appeared, forming a close "collaboration" with insects that carried their pollen.

They began to spread rapidly throughout the land.

The largest aromorphosis is the formation of a flower and fruit.

5. Results of the Mesozoic era

The Mesozoic era is the era of middle life. It is named so because the flora and fauna of this era are transitional between the Paleozoic and Cenozoic. In the Mesozoic era, the modern outlines of the continents and oceans, modern marine fauna and flora are gradually formed.

The Andes and Cordilleras, mountain ranges of China and East Asia were formed. The basins of the Atlantic and Indian oceans formed. The formation of depressions has begun Pacific Ocean. There were also serious aromorphoses in the plant and animal worlds. Gymnosperms become the predominant division of plants, and in the animal kingdom, the appearance of a four-chambered heart and the formation of a uterus are of the same importance.

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Mesozoic era

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Cretaceous period

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Reasons for the extinction of dinosaurs. The Cretaceous is the last period of the Mesozoic era. Characteristics of vegetation and animals, their aromorphoses.

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Development of life in the Mesozoic era

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History of the study of dinosaurs.

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Silurian period of the Paleozoic era

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Mesozoic era

Mass Permian extinction. Causes of the extinction of dinosaurs and many other living organisms at the turn of the Cretaceous and Paleogene. Beginning, middle and end of the Mesozoic. Animal world of the Mesozoic era.

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Mesozoic era

The Mesozoic era (252-66 million years ago) is the second era of the fourth eon - the Phanerozoic. Its duration is 186 million years. The main features of the Mesozoic: the modern outlines of the continents and oceans, modern marine fauna and flora are gradually formed. The Andes and Cordilleras, mountain ranges of China and East Asia were formed. The basins of the Atlantic and Indian oceans formed. The formation of the Pacific Ocean depressions began.

Periods of the Mesozoic Era

Triassic period, Triassic, - the first period of the Mesozoic era, lasts 51 million years.

This is the time of the formation of the Atlantic Ocean. The single continent of Pangea again begins to break into two parts - Gondwana and Laurasia. Inland continental water bodies begin to dry up actively. The depressions remaining from them are gradually filled with rock deposits.

New mountain heights and volcanoes appear, which show increased activity. A huge part of the land is also occupied by desert zones with weather conditions unsuitable for the life of most species of living beings. Salt levels in water bodies are rising. During this time period, representatives of birds, mammals and dinosaurs appear on the planet. Read more about the Triassic period.

Jurassic period (Jura)- the most famous period of the Mesozoic era.

It got its name thanks to the sedimentary deposits of that time found in the Jura (mountains of Europe). The average period of the Mesozoic era lasts about 56 million years. The formation of modern continents begins - Africa, America, Antarctica, Australia. But they are not yet in the order to which we are accustomed.

Deep bays and small seas appear, separating the continents. The active formation of mountain ranges continues. The Arctic Sea floods the north of Laurasia. As a result, the climate is humidified, and vegetation forms on the site of deserts.

Cretaceous (Cretaceous)- the final period of the Mesozoic era, occupies a time period of 79 million years. Angiosperms appear. As a result of this, the evolution of representatives of the fauna begins. The movement of the continents continues - Africa, America, India and Australia are moving away from each other. The continents of Laurasia and Gondwana begin to disintegrate into continental blocks. Huge islands are formed in the south of the planet.

The Atlantic Ocean is expanding. The Cretaceous period is the heyday of flora and fauna on land. In connection with the evolution flora, fewer minerals enter the seas and oceans. The number of algae and bacteria in water bodies is reduced. Read in detail - Cretaceous period

The climate of the Mesozoic era

The climate of the Mesozoic era at the very beginning was the same on the entire planet. The air temperature at the equator and the poles was kept at the same level.

At the end of the first period of the Mesozoic era, a drought reigned on Earth for most of the year, which was briefly replaced by rainy seasons. But, despite the arid conditions, the climate became much colder than it was during the Paleozoic period.

Some species of reptiles have fully adapted to cold weather. Mammals and birds would later evolve from these animal species.

In the Cretaceous, it gets even colder. All continents have their own climate. Tree-like plants appear, which lose their foliage during the cold season. Snow begins to fall at the North Pole.

Plants of the Mesozoic Era

At the beginning of the Mesozoic, the continents were dominated by club mosses, various ferns, the ancestors of modern palms, conifers and ginkgo trees.

In the seas and oceans, the dominance belonged to the algae that formed the reefs.

The increased humidity of the climate of the Jurassic period led to the rapid formation of the plant mass of the planet. The forests consisted of ferns, conifers and cycads. Tui and araucaria grew near water bodies. In the middle of the Mesozoic era, two belts of vegetation formed:

1. Northern, dominated by herbaceous ferns and ginkgo trees;
2. Southern.

   Tree ferns and cicadas reigned here.

In the modern world, ferns, cycads (palm trees reaching a size of 18 meters) and cordaites of that time can be found in tropical and subtropical forests.

Horsetails, club mosses, cypresses and spruce trees practically did not have any differences from those that are common in our time.

The Cretaceous period is characterized by the appearance of plants with flowers. In this regard, butterflies and bees appeared among insects, thanks to which flowering plants could quickly spread across the planet.

Also at this time, ginkgo trees begin to grow with foliage falling in the cold season. Coniferous forests of this time period are very similar to modern ones.

They include yews, firs and cypresses.

The development of higher gymnosperms lasts throughout the Mesozoic era. These representatives of the terrestrial flora got their name due to the fact that their seeds did not have an outer protective shell. The most widespread are cycads and bennettites.

In appearance, cycads resemble tree ferns or cycads. They have straight stems and massive feather-like leaves. Bennettites are trees or shrubs. Outwardly similar to cycads, but their seeds are covered with a shell. This brings plants closer to angiosperms.

In the Cretaceous, angiosperms appear. From this moment begins a new stage in the development of plant life. Angiosperms (flowering) are at the top rung of the evolutionary ladder.

They have special reproductive organs - stamens and pistil, which are located in the flower bowl. Their seeds, unlike gymnosperms, hide a dense protective shell. These plants of the Mesozoic era quickly adapt to any climatic conditions and actively develop. Per short term angiosperms began to dominate the entire Earth. Their various types and forms have reached modern world- eucalyptus, magnolias, quince, oleanders, walnut trees, oaks, birches, willows and beeches.

Of the gymnosperms of the Mesozoic era, now we are only familiar with coniferous species - fir, pine, sequoia and some others. The evolution of plant life of that period significantly overtook the development of representatives of the animal world.

Animals of the Mesozoic Era

Animals in the Triassic period of the Mesozoic era actively evolved.

A huge variety of more developed creatures was formed, which gradually replaced the ancient species.

One of these types of reptiles became pelycosaurs similar to animals - sailing lizards.

On their backs was a huge sail, similar to a fan. They were replaced by therapsids, which were divided into 2 groups - predators and herbivores.

Their paws were powerful, their tails were short. In terms of speed and endurance, therapsids far surpassed pelycosaurs, but this did not save their species from extinction at the end of the Mesozoic era.

The evolutionary group of lizards, from which mammals would later emerge, are the cynodonts (dog teeth). These animals got their name due to powerful jaw bones and sharp teeth, with which they could easily chew raw meat.

Their bodies were covered with thick fur. Females laid eggs, but newborn cubs fed on mother's milk.

At the beginning of the Mesozoic era, formed the new kind pangolins - archosaurs (ruling reptiles).

They are the ancestors of all dinosaurs, pterosaurs, plesiosaurs, ichthyosaurs, placodonts, and crocodylomorphs. Archosaurs, adapted to the climatic conditions on the coast, became predatory thecodonts.

They hunted on land near water bodies. Most thecodonts walked on four legs. But there were also individuals who ran on their hind legs. In this way, these animals developed incredible speed. Over time, thecodonts evolved into dinosaurs.

By the end of the Triassic period, two species of reptiles dominated. Some are the ancestors of the crocodiles of our time.

Others have become dinosaurs.

Dinosaurs are not like other lizards in body structure. Their paws are located under the body.

This feature allowed the dinosaurs to move quickly. Their skin is covered with waterproof scales. Lizards move on 2 or 4 legs, depending on the species. The first representatives were fast coelophyses, powerful herrerasaurs and huge plateosaurs.

In addition to dinosaurs, archosaurs gave rise to another type of reptile that is different from the rest.

These are pterosaurs - the first pangolins that can fly. They lived near water bodies, and ate various insects for food.

The fauna of the sea depths of the Mesozoic era is also characterized by a variety of species - ammonites, bivalves, shark families, bony and ray-finned fish. The most outstanding predators were the underwater lizards that appeared not so long ago. Dolphin-like ichthyosaurs had high speed.

One of the giant representatives of ichthyosaurs is Shonisaurus. Its length reached 23 meters, and its weight did not exceed 40 tons.

Lizard-like notosaurs had sharp fangs.

Plakadonts, similar to modern newts, searched the seabed for mollusk shells, which they bit with their teeth. Tanystrophei lived on land. Long (2-3 times the size of the body), slender necks allowed them to catch fish standing on the shore.

1 more group sea ​​lizards Triassic period - plesiosaurs. At the beginning of the era, plesiosaurs reached a size of only 2 meters, and by the middle of the Mesozoic evolved into giants.

The Jurassic period is the time of the development of dinosaurs.

The evolution of plant life gave impetus to the emergence different types herbivorous dinosaurs. And this, in turn, led to an increase in the number of predatory individuals. Some types of dinosaurs were the size of a cat, while others were as large as giant whales. by the most giant specimens are diplodocus and brachiosaurus, reaching a length of 30 meters.

Their weight was about 50 tons.

Archeopteryx is the first creature to stand on the border between lizards and birds. Archeopteryx did not yet know how to fly long distances. Their beaks were replaced by jaws with sharp teeth. The wings ended in fingers. Archeopteryx were the size of modern crows.

They lived mainly in forests, and ate insects and various seeds.

In the middle of the Mesozoic era, pterosaurs are divided into 2 groups - pterodactyls and rhamphorhynchus.

Pterodactyls lacked a tail and feathers. But there were large wings and a narrow skull with a few teeth. These creatures lived in flocks on the coast. During the day they hunted for food, and at night they hid in the trees. Pterodactyls ate fish, shellfish and insects. To take to the skies, this group of pterosaurs had to jump from high places. Ramphorhynchus also lived on the coast. They ate fish and insects. They had long tails, which had a blade at the end, narrow wings and a massive skull with teeth of different sizes, which were convenient for catching slippery fish.

The most dangerous predator of the deep sea was Liopleurodon, which weighed 25 tons.

Huge coral reefs were formed, in which ammonites, belemnites, sponges and sea mats settled. Representatives of the shark family and bone fish develop. New species of plesiosaurs and ichthyosaurs, sea turtles and crocodiles appeared. Saltwater crocodiles have flippers instead of legs. This feature allowed them to increase their speed in the aquatic environment.

In the Cretaceous period of the Mesozoic era, bees and butterflies appeared. Insects carried pollen, and flowers gave them food.

Thus began a long-term cooperation between insects and plants.

The most famous dinosaurs of that time were predatory tyrannosaurs and tarbosaurs, herbivorous bipedal iguanodons, quadrupedal rhinoceros-like Triceratops and small armored ankylosaurs.

Most of the mammals of that period belong to the subclass Allotherium.

These are small animals, similar to mice, weighing no more than 0.5 kg. The only exceptional species is repenomamas. They grew up to 1 meter and weighed 14 kg. At the end of the Mesozoic era, the evolution of mammals takes place - the ancestors of modern animals are separated from allotheria. They were divided into 3 types - oviparous, marsupial and placental. It is they who at the beginning of the next era replace the dinosaurs. From the placental species of mammals, rodents and primates appeared. Purgatorius became the first primates.

From the marsupial species, modern opossums originated, and the egg-laying species gave rise to platypuses.

The air space is dominated by early pterodactyls and new types of flying reptiles - Orcheopteryx and Quetzatcoatl. These were the most gigantic flying creatures in the entire history of the development of our planet.

Together with representatives of pterosaurs, birds dominate the air. In the Cretaceous period, many ancestors of modern birds appeared - ducks, geese, loons. The length of the birds was 4-150 cm, weight - from 20 g. up to several kilograms.

Huge predators reigned in the seas, reaching a length of 20 meters - ichthyosaurs, plesiosaurs and mososaurs. Plesiosaurs were very long neck and small head.

Their large size did not allow them to develop great speed. The animals ate fish and shellfish. Mososaurs replaced saltwater crocodiles. These are giant predatory lizards with an aggressive character.

At the end of the Mesozoic era, snakes and lizards appeared, the species of which have reached the modern world without changing. Turtles of this time period also did not differ from those that we see now.

Their weight reached 2 tons, length - from 20 cm to 4 meters.

By the end of the Cretaceous period, most reptiles begin to die out en masse.

Minerals of the Mesozoic era

A large number of deposits of natural resources are associated with the Mesozoic era.

These are sulfur, phosphorites, polymetals, building and combustible materials, oil and natural gas.

On the territory of Asia, in connection with active volcanic processes, the Pacific belt was formed, which gave the world large deposits of gold, lead, zinc, tin, arsenic and other types of rare metals. In terms of coal reserves, the Mesozoic era is significantly inferior to Paleozoic era, but even during this period several large deposits of brown and hard coal were formed - the Kansk basin, Bureinsky, Lensky.

Mesozoic oil and gas fields are located in the Urals, Siberia, Yakutia, Sahara.

Phosphorite deposits have been found in the Volga and Moscow regions.

To the table: Phanerozoic eon

01 of 04. Periods of the Mesozoic Era

The Paleozoic era, like all major eras on the geological time scale, has ended mass extinction. The Permian Mass Extinction is considered the largest loss of species in the history of the Earth. Almost 96% of all living species were destroyed due to the large number of volcanic eruptions that led to massive and relatively rapid climate change during the Mesozoic era.

The Mesozoic era is often referred to as the "Age of the Dinosaurs" because it is the time period in which the dinosaurs evolved and eventually became extinct.

The Mesozoic era is divided into three periods: Triassic, Jurassic and Cretaceous.

02 of 04. Triassic period (251 million years ago - 200 million years ago)

Fossil of Pseudopalatus from the Triassic period.

National Park Service

The beginning of the Triassic period was rather poor in terms of life forms on Earth. Because there were so few species left after the Permian mass extinction, it took a very long time for repopulation and biodiversity to increase. The relief of the Earth also changed during this period of time. At the beginning of the Mesozoic era, all the continents were united into one large continent. This supercontinent is called Pangea.

In the Triassic period, the separation of the continents began due to plate tectonics and continental drift.

When animals began to emerge from the oceans again and colonize the almost empty land, they also learned to burrow to protect themselves from change. environment. For the first time in history, amphibians such as frogs appeared, and then reptiles such as turtles, crocodiles and, ultimately, dinosaurs.

By the end of the Triassic period, birds also appeared, splitting off from the dinosaur branch in the phylogenetic tree.

Plants were also few. In the Triassic period, they began to flourish again.

Development of life in the Mesozoic era

Most land plants at that time were conifers or ferns. By the end of the Triassic, some of the ferns had developed seeds for reproduction. Unfortunately, another mass extinction ended the Triassic period. This time, about 65% of the species on Earth did not survive.

03 of 04. Jurassic (200 million years ago - 145 million years ago)

Plesiosaurus from the Jurassic period.

Tim Evanson

After the Triassic mass extinction, there was a diversification of life and species to fill the niches that were left open. Pangea broke into two large parts - Laurasia was a land mass in the north, and Gondwana was in the south. Between these two new continents was the Tethys Sea. The varied climates on every continent have allowed many new species to appear for the first time, including lizards and small mammals. Nevertheless, dinosaurs and flying reptiles continued to dominate on earth and in the sky.

There were many fish in the oceans.

Plants bloomed for the first time on earth. There were numerous extensive pastures for herbivores, which also made it possible to feed predators. The Jurassic period was like the Renaissance for life on Earth.

04 of 04. Cretaceous period (145 million years ago - 65 million years ago)

Fossil Pachycephalosaurus from the Cretaceous period.

Tim Evanson

The Cretaceous period is the last period of the Mesozoic era. Favorable conditions for life on Earth continued from the Jurassic to the early Cretaceous. Laurasia and Gondwana began to expand even more, and eventually formed the seven continents that we see today. As the landmass expanded, the climate on Earth was warm and humid. These were very favorable conditions for the flourishing of plant life. Flowering plants began to multiply and dominate the land.

Since plant life was plentiful, the herbivore population also increased, which in turn led to an increase in the number and size of predators. Mammals also began to separate into many species, as did the dinosaurs.

Life in the ocean developed in a similar way. Warm and humid climate supported high levels seas. This contributed to the increase in the biodiversity of marine species.

All the tropical regions of the Earth were covered with water, so the climatic conditions were largely ideal for a variety of life.

As before, these almost ideal conditions would have to end sooner or later. This time, it is believed that the mass extinction that ended the Cretaceous period and then the entire Mesozoic era was caused by one or more large meteors crashing into the Earth. The ash and dust thrown into the atmosphere blocked the sun, slowly killing all the lush plant life that had accumulated on land.

Likewise, most of the species in the ocean also disappeared during this time. As there were fewer and fewer plants, the herbivores also gradually died out. Everything died out: from insects to large birds and mammals and, of course, dinosaurs. Only small animals that were able to adapt and survive in conditions of small amounts of food were able to see the beginning of the Cenozoic era.

Sources

Mesozoic deposits- sediments, sediments formed in the Mesozoic era. Mesozoic deposits include the Triassic, Jurassic and Cretaceous systems (periods).

In Mordovia, only Jurassic and Cretaceous sedimentary rocks are present. In the Triassic period (248 - 213 Ma) the territory of Mordovia was dry land and no sediments were deposited. In the Jurassic period (213-144 million years) there was a sea throughout the entire territory of the republic, in which clays, sands, less often nodules of phosphorites, and carbonaceous shales accumulated.

Jurassic deposits come to the surface on 20 - 25% of the area (mainly along river valleys), with a thickness of 80 - 140 m. Deposits of minerals are associated with them - oil shale and phosphorites. In the Cretaceous period (144 - 65 million years) the sea continued to exist, and deposits of this age come to the surface on 60 - 65% of the territory in all regions of the Republic of Mordovia.

Represented by 2 groups - Lower and Upper Cretaceous. On the eroded surface of the Jurassic deposits (oil shales and dark clays), Lower Cretaceous deposits occur: phosphorite conglomerate, greenish-gray and black clays and sands with a total thickness of up to 110 m. Upper Cretaceous deposits consist of light gray and white chalk, marl, flask and compose the Cretaceous mountains in the southeastern regions of the Republic of Mordovia.

Thin layers are marked by green glauconite and phosphorite-bearing sands. In other layers there are concretions and nodules of phosphorites, petrified remains of organisms (belemnites, popularly called "devil's fingers"). The total thickness is about 80 m.

Mesozoic era

The Atemarskoye and Kulyasovskoye chalk deposits, the Alekseevskoye deposit of cement raw materials are confined to the Upper Cretaceous deposits.

[edit] Source

A. A. Mukhin. Alekseevsky cement plant quarry. 1965

Mesozoic era

The Mesozoic era began about 250 and ended 65 million years ago. It lasted 185 million years. The Mesozoic era is divided into the Triassic, Jurassic and Cretaceous periods with a total duration of 173 million years. The deposits of these periods constitute the corresponding systems, which together form the Mesozoic group.

The Mesozoic is known primarily as the era of the dinosaurs. These giant reptiles obscure all other groups of living beings.

But don't forget about others. After all, it was the Mesozoic - the time when real mammals, birds, flowering plants appeared - that the modern biosphere actually formed.

And if in the first period of the Mesozoic - the Triassic, there were still many animals from the Paleozoic groups on Earth that could survive the Permian catastrophe, then in the last period - the Cretaceous, almost all those families that flourished in the Cenozoic era were already formed.

The Mesozoic era was a transitional period in the development of the earth's crust and life. It can be called the geological and biological Middle Ages.
The beginning of the Mesozoic era coincided with the end of the Variscinian mountain-building processes, it ended with the beginning of the last powerful tectonic revolution - Alpine folding.

In the Southern Hemisphere in the Mesozoic, the disintegration of the ancient continent of Gondwana ended, but on the whole, the Mesozoic era here was an era of relative calm, only occasionally and briefly disturbed by slight folding.

The early stage in the development of the plant kingdom, the paleophyte, was characterized by the dominance of algae, psilophytes, and seed ferns. The rapid development of more highly developed gymnosperms, which characterizes the “vegetative Middle Ages” (mesophyte), began in the Late Permian era and ended by the beginning of the Late Cretaceous era, when the first angiosperms, or flowering plants (Angiospermae), began to spread.

From the Late Cretaceous, the Cainophyte began - the modern period in the development of the plant kingdom.

This made it difficult for them to settle. The development of seeds allowed plants to lose such a close dependence on water. The ovules could now be fertilized by pollen carried by the wind or insects, and water thus no longer predetermined reproduction. In addition, in contrast to the unicellular spore with its relatively small supply nutrients, the seed has a multicellular structure and is able to provide food for a young plant for longer early stages development.

Under adverse conditions, the seed can remain viable for a long time. Having a strong shell, it reliably protects the embryo from external dangers. All these advantages gave seed plants a good chance in the struggle for existence. The ovule (ovum) of the first seed plants was unprotected and developed on special leaves; the seed that arose from it also did not have an outer shell.

Among the most numerous and most curious gymnosperms of the beginning of the Mesozoic era, we find the cycads (Cycas), or sagos. Their stems were straight and columnar, similar to tree trunks, or short and tuberous; they bore large, long and usually feathery leaves
(for example, the genus Pterophyllum, whose name in translation means "pinnate leaves").

Outwardly, they looked like tree ferns or palm trees.
In addition to cycads, bennettitales (Bennettitales), represented by trees or shrubs, have become of great importance in the mesophyte. Basically, they resemble true cycads, but their seed begins to acquire a strong shell, which gives Bennettites a resemblance to angiosperms.

There are other signs of adaptation of the bennettites to the conditions of a more arid climate.

In the Triassic, new forms come to the fore.

Conifers quickly settle, and among them are firs, cypresses, yews. Of the Ginkgoaceae, the genus Baiera is widespread. The leaves of these plants had the shape of a fan-shaped plate, deeply dissected into narrow lobes. Ferns have captured damp shady places along the banks of small reservoirs (Hausmannia and other Dipteridacea). Known among the ferns and forms that grew on the rocks (Gleicheniacae). Horsetails (Equisetites, Phyllotheca, Schizoneura) grew in swamps, but did not reach the size of their Paleozoic ancestors.
In the middle mesophyte (Jurassic period), the mesophytic flora reached the climax of its development.

The hot tropical climate in what is today the temperate zone was ideal for tree ferns to thrive, while smaller fern species and herbaceous plants favored temperate zone. Among the plants of this time, gymnosperms continue to play a dominant role.
(primarily cicadas).

The Cretaceous period is marked by rare changes in vegetation.

The flora of the Lower Cretaceous still resembles in composition the vegetation of the Jurassic period. Gymnosperms are still widespread, but their dominance ends by the end of this time.

Even in the Lower Cretaceous, the most progressive plants suddenly appeared - angiosperms, the predominance of which characterizes the era of new plant life, or cenophyte.

Angiosperms, or flowering (Angiospermae), occupy the highest rung of the evolutionary ladder of the plant world.

Their seeds are enclosed in a strong shell; there are specialized reproductive organs (stamen and pistil), collected in a flower with bright petals and a calyx. Flowering plants appear somewhere in the first half of the Cretaceous, most likely in a cold and arid mountain climate with large temperature fluctuations.
With the gradual cooling that marked the chalk, they captured more and more new areas on the plains.

Quickly adapting to new environment they have evolved at an astonishing rate. Fossils of the first true angiosperms are found in the Lower Cretaceous rocks of West Greenland, and a little later also in Europe and Asia. Within a relatively short time, they spread throughout the Earth and reached a great diversity.

From the end of the Early Cretaceous, the balance of power began to change in favor of angiosperms, and by the beginning of the Upper Cretaceous, their superiority became widespread. Cretaceous angiosperms belonged to evergreen, tropical or subtropical types, among them were eucalyptus, magnolia, sassafras, tulip trees, Japanese quince trees (quince), brown laurels, walnut trees, plane trees, oleanders. These thermophilic trees coexisted with the typical flora of the temperate zone: oaks, beeches, willows, birches.

For the gymnosperms, it was a time of surrender. Some species have survived to this day, but their total number has been descending all these centuries. A definite exception is conifers, which are found in abundance today.
In the Mesozoic, plants made a great leap forward, surpassing animals in terms of development.

Mesozoic invertebrates were already approaching modern ones in character.

A prominent place among them was occupied by cephalopods, to which modern squids and octopuses belong. The Mesozoic representatives of this group included ammonites with a shell twisted into a "ram's horn", and belemnites, the inner shell of which was cigar-shaped and overgrown with the flesh of the body - the mantle.

Belemnite shells are popularly known as "devil's fingers". Ammonites were found in the Mesozoic in such quantities that their shells are found in almost all marine sediments of this time.

Ammonites appeared as early as the Silurian, they experienced their first heyday in the Devonian, but reached their highest diversity in the Mesozoic. In the Triassic alone, more than 400 new genera of ammonites arose.

Particularly characteristic of the Triassic were the ceratids, which were widely distributed in the Upper Triassic marine basin of Central Europe, the deposits of which are known in Germany as shell limestone.

By the end of the Triassic, most ancient groups of ammonites die out, but representatives of phylloceratids (Phylloceratida) have survived in Tethys, the giant Mesozoic Mediterranean Sea. This group developed so rapidly in the Jurassic that the ammonites of this time surpassed the Triassic in the variety of forms.

In the Cretaceous, cephalopods, both ammonites and belemnites, are still numerous, but in the course of the Late Cretaceous, the number of species in both groups begins to decline. Among the ammonites at this time, aberrant forms with an incompletely twisted hook-shaped shell (Scaphites), with a shell elongated in a straight line (Baculites) and with a shell irregular shape(Heteroceras).

These aberrant forms appeared, most likely, as a result of changes in the course of individual development and narrow specialization. The final Upper Cretaceous forms of some ammonite branches are distinguished by sharply increased shell sizes. In the genus Parapachydiscus, for example, the shell diameter reaches 2.5 m.

The mentioned belemnites also acquired great importance in the Mesozoic.

Some of their genera, such as Actinocamax and Belenmitella, are important as guide fossils and are successfully used for stratigraphic subdivision and accurate age determination of marine sediments.
At the end of the Mesozoic, all ammonites and belemnites became extinct.

Of the cephalopods with an outer shell, only the genus Nautilus has survived to this day. Forms with an internal shell are more widely distributed in modern seas - octopuses, cuttlefish and squids, remotely related to belemnites.
The Mesozoic era was a time of unstoppable expansion of vertebrates. Of the Paleozoic fishes, only a few passed into the Mesozoic, as did the genus Xenacanthus, the last representative of Paleozoic freshwater sharks known from freshwater deposits of the Australian Triassic.

Sea sharks continued to evolve throughout the Mesozoic; Most modern genera were already present in the seas of the Cretaceous, in particular, Carcharias, Carcharodon, lsurus, etc.

Ray-finned fish, which arose at the end of the Silurian, originally lived only in freshwater reservoirs, but with the Permian they begin to enter the seas, where they multiply unusually and from the Triassic to the present day retain their dominant position.
The reptiles, which became truly the dominant class of this era, were most widespread in the Mesozoic.

In the course of evolution, a variety of genera and species of reptiles appeared, often of very impressive size. Among them were the largest and most bizarre land animals that the earth had ever worn.

As already mentioned, by anatomical structure the oldest reptiles were close to labyrinthodonts. The oldest and most primitive reptiles were clumsy cotylosaurs (Cotylosauria), which appeared already at the beginning of the Middle Carboniferous and became extinct by the end of the Triassic. Among cotylosaurs, both small animal-eating and relatively large herbivorous forms (pareiasaurs) are known.

The descendants of cotilosaurs gave rise to the whole diversity of the world of reptiles. One of the most interesting groups reptiles that developed from cotylosaurs were animal-like (Synapsida, or Theromorpha), their primitive representatives (pelycosaurs) have been known since the end of the Middle Carboniferous. In the middle of the Permian period, pelycosaurs, known mainly from North America, die out, but in the Old World they are replaced by more progressive forms that form the Therapsida order.
The carnivorous theriodonts (Theriodontia) included in it are already very similar to primitive mammals, and it is no coincidence that the first mammals developed from them by the end of the Triassic.

During the Triassic period, many new groups of reptiles appeared.

These are turtles, and ichthyosaurs ("lizard fish") well adapted to marine life, resembling dolphins in appearance, and placodonts, clumsy armored animals with powerful flattened teeth adapted for crushing shells, and also plesiosaurs living in the seas, which had a relatively small head, more or less elongated neck, broad body, flipper-like paired limbs and short tail; Plesiosaurs vaguely resemble giant shellless tortoises.

In the Jurassic, plesiosaurs, like ichthyosaurs, flourished. Both of these groups remained very numerous in the Early Cretaceous, being extremely characteristic predators of the Mesozoic seas.
From an evolutionary point of view, one of the most important groups of Mesozoic reptiles were thecodonts, medium-sized predatory reptiles of the Triassic period, which gave rise to the most diverse groups - crocodiles, dinosaurs, flying pangolins, and, finally, birds.

However, the most remarkable group of Mesozoic reptiles were the well-known dinosaurs.

They evolved from thecodonts as early as the Triassic and occupied a dominant position on Earth in the Jurassic and Cretaceous. Dinosaurs are represented by two groups, completely separate - saurischia (Saurischia) and ornithischia (Ornithischia). In the Jurassic, among the dinosaurs, real monsters could be found, up to 25-30 m long (with a tail) and weighing up to 50 tons. Of these giants, the most famous forms are Brontosaurus, Diplodocus and Brachiosaurus.

And in the Cretaceous period, the evolutionary progress of dinosaurs continued. Of the European dinosaurs of this time, bipedal iguanodonts are widely known, in America, four-legged horned dinosaurs (Triceratops) Styracosaurus, etc.), somewhat reminiscent of modern rhinoceroses, were widely used.

Relatively small armored dinosaurs (Ankylosauria), covered with a massive bone shell, are also interesting. All these forms were herbivorous, as were the giant duck-billed dinosaurs (Anatosaurus, Trachodon, etc.), which moved on two legs.

In the chalk they flourished and carnivorous dinosaurs, the most remarkable of which were such forms as Tyrannosaurus rex, whose length exceeded 15 m, Gorgosaurus and Tarbosaurus.

All these forms, which turned out to be the greatest land predatory animals in the entire history of the Earth, moved on two legs.

At the end of the Triassic, the first crocodiles also originated from thecodonts, which became abundant only in the Jurassic (Steneosaurus and others). In the Jurassic, flying lizards appeared - pterosaurs (Pterosauria), also descended from thecodonts.
Among the flying lizards of the Jura, the most famous are the rhamphorhynchus (Rhamphorhynchus) and the pterodactyl (Pterodactylus), of the Cretaceous forms, the relatively very large Pteranodon (Pteranodon) is the most interesting.

Flying pangolins become extinct by the end of the Cretaceous.
In the Cretaceous seas, giant predatory mosasaur lizards, exceeding 10 m in length, became widespread. Among modern lizards, they are closest to monitor lizards, but differ from them, in particular, in flipper-like limbs.

By the end of the Cretaceous, the first snakes (Ophidia) also appeared, apparently descended from burrowing lizards.
By the end of the Cretaceous, the mass extinction of characteristic Mesozoic groups of reptiles, including dinosaurs, ichthyosaurs, plesiosaurs, pterosaurs and mosasaurs, occurs.

Representatives of the bird class (Aves) first appear in the Jurassic deposits.

Brief information about the Mesozoic era

The remains of Archeopteryx (Archaeopteryx), a widely known and so far the only known first bird, were found in Upper Jurassic lithographic shale, near the Bavarian city of Solnhofen (Germany). During the Cretaceous, bird evolution proceeded at a rapid pace; genera characteristic of this time were ichthyornis (Ichthyornis) and hesperornis (Hesperornis), which still had serrated jaws.

The first mammals (Mattalia), modest animals not exceeding the size of a mouse, descended from animal-like reptiles in the late Triassic.

Throughout the Mesozoic, they remained few in number, and by the end of the era, the original genera had largely died out.

The most ancient group of mammals were triconodonts (Triconodonta), to which the most famous of the Triassic mammals Morganucodon belongs. Appears in jura
a number of new groups of mammals - Symmetrodonta, Docodonta, Multituberculata and Eupantotheria.

Of all these groups, only the Multituberculata (multi-tubercular) survived the Mesozoic, the last representative of which dies out in the Eocene. Polytuberculates were the most specialized of the Mesozoic mammals, convergently they had some similarities with rodents.

The ancestors of the main groups of modern mammals - marsupials (Marsupialia) and placental (Placentalia) were Eupantotheria. Both marsupials and placentals appeared in the Late Cretaceous. The most ancient group of placentals are insectivores (lnsectivora), which have survived to this day.

Aeon. The Mesozoic consists of three periods - Cretaceous, Jurassic and Triassic. The Mesozoic era lasted for 186 million years, starting from 251 million years ago and ending 66 million years ago. In order not to get confused in eons, eras and periods, use the geochronological scale, which is located as a visual clue.

The lower and upper boundaries of the Mesozoic are defined by two mass extinctions. The lower limit is marked by the largest extinction in the history of the Earth - the Permian or Permian-Triassic, when about 90-96% of marine animals and 70% of land animals disappeared. The upper limit is marked by perhaps the most famous extinction - the Cretaceous-Paleogene, when all dinosaurs died out.

Periods of the Mesozoic Era

1. or Triassic period. It lasted from 251 to 201 million years ago. The Triassic is known for the fact that during this period the mass extinction ends and the gradual restoration of the animal world of the Earth begins. Also in the Triassic period, Pangea, the largest supercontinent in history, begins to break apart.

2. or Jurassic. It lasted from 201 to 145 million years ago. Active development of plants, marine and land animals, giant lizard dinosaurs and mammals.

3. or Cretaceous period. It lasted from 145 to 66 million years ago. The beginning of the Cretaceous period is characterized by the further development of flora and fauna. Large reptile dinosaurs reigned on earth, some of which reached 20 meters in length and eight meters in height. The mass of some dinosaurs reached fifty tons. The first birds appeared in the Cretaceous period. At the end of the period there was a Cretaceous catastrophe. As a result of this catastrophe, many species of plants and animals disappeared. The biggest losses were among the dinosaurs. At the end of the period, ALL dinosaurs died out, as well as many gymnosperms, many aquatic reptiles, pterosaurs, ammonites, as well as from 30 to 50% of the species of all animal species that could survive.

Animals of the Mesozoic Era

Apatosaurus

Archeopteryx

Askeptosaurus

Brachiosaurus

Diplodocus

sauropods

ichthyosaurs

Camarasaurus

Liopleurodon

Mastodonsaurus

Mosasaurs

Nothosaurs

Plesiosaurs

sclerosaurus

Tarbosaurus

tyrannosaurus rex

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The Mesozoic era is a period in the geological history of the Earth from 251 million to 65 million years ago. It is at this stage in the history of the Earth that the formation of the main contours of modern continents and mountain building takes place. on the periphery of the Pacific, Atlantic and Indian oceans. Favorable climatic conditions and the division of land contributed to important evolutionary events in the life of the biosphere - by the end of the Mesozoic, the main part of the species diversity of the Earth's life approached its modern state. Today we can judge the natural and climatic conditions, tectonic processes, the composition of the atmosphere, the animal and plant kingdom of the Mesozoic era by a lot of geological evidence. As is known, the closer the events are to the modern period of history, the more interesting and extensive information about the past can be gleaned from the geological record of the Earth.
If for previous epochs the main data were obtained through the study of precipitation rocks modern continents, then already for the second half of the Mesozoic and beyond, scientists have important indications for the seas and oceans. The Paleozoic era ended with the Hercynian stage of folding. The folded systems formed in the Paleozoic at the site of the North Atlantic, Ural-Tien Shan and Mongolian-Okhotsk geosynclines contributed to the connection of the northern platforms into a huge single massif - Laurasia. This continent stretches from the Rocky Mountains of North America to the Verkhoyansk Range in northeast Asia.

The Southern Hemisphere had its own huge platform - the mainland Gondwana, uniting South America, Antarctica, Africa, Hindustan and Australia. At a certain period in the history of the Earth, Laurasia and Gondwana were one whole - the supercontinent Pangea. But it was in the Mesozoic era that the gradual disintegration of Pangea and the process of formation of modern continents and oceans began. Therefore, the Mesozoic is often called a transitional period in the development of the earth's crust, a real geological Middle Ages.

This era is best remembered as the era of the dinosaurs. It lasted about half as long as the Paleozoic era, but was rich in events. It was a time when plants, fish, mollusks, and especially reptiles, reached enormous sizes, as if everything on Earth was then on megavitamins. Dinosaurs were buried in giant ferns and huge trees, while pterosaurs (flying reptiles) cruised the sky. Climatic conditions were warm throughout.

While geologists can only guess at what forces caused the supercontinent Pangea to break up into Laurasia and Gondwana at this time, the example of Antarctica suggests magma "hot spots" causing fractures throughout the globe. In some areas, dinosaurs and plants became isolated for millions of years and acquired special features, depending on their habitats, as well as local food and temperature conditions. Even small mammals have begun to get under the feet of carnivorous dinosaurs like Tyrannosaurus Rex as an occasional snack.

During the Mesozoic Era, more modern forms of insects, corals, marine organisms, and flowering plants began to develop. Everything was really wonderful, when suddenly the dinosaurs and many other animals became extinct. Many scientists believe that this was due to a collision with a large asteroid and the resulting atmospheric smoke, volcanic eruptions and mostly inclement weather observed in subsequent years. The sun couldn't break through the ash and smoke, the water was polluted, and Earth certainly wasn't a big resort.

The Mesozoic era is divided into three periods: Triassic, Jurassic and Cretaceous.

Mesozoic - an era of tectonic, climatic and evolutionary activity. There is a formation of the main contours of modern continents and mountain building on the periphery of the Pacific, Atlantic and Indian oceans; the division of the landmass contributed to speciation and other important evolutionary events. The climate was warm throughout the entire time period, which also played an important role in the evolution and formation of new animal species. By the end of the era, the main part of the species diversity of life approached its modern state.

Encyclopedic YouTube

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✪ The history of the development of life in the Mesozoic era. Part 1. Video lesson in biology Grade 11

✪ Dinosaurs (says paleontologist Vladimir Alifanov)

✪ Dinosaurs and other ancient animals (a selection of esters)

Subtitles

Geological periods

• Triassic period (251.902 ± 0.024 - 201.3 ± 0.2)
• Jurassic period (201.3 ± 0.2 - 145.0)
• Cretaceous period (145.0 - 66.0).

Tectonics and paleogeography

Compared to the vigorous mountain building of the Late Paleozoic, Mesozoic tectonic deformations can be considered relatively mild. The main tectonic event was the breakup of the Pangea supercontinent into a northern part (Laurasia) and a southern part (Gondwana). Later, they also broke up. At the same time, the Atlantic Ocean was formed, surrounded mainly by passive continental margins (for example, the east coast of North America). The extensive transgressions that prevailed in the Mesozoic led to the emergence of numerous inland seas.

By the end of the Mesozoic, the continents practically took on their modern shape. Laurasia divided into Eurasia and North America, Gondwana - into South America, Africa, Australia, Antarctica and the Indian subcontinent, the collision of which with the Asian continental plate caused intense orogeny with the rise of the Himalayan mountains.

Africa

At the beginning of the Mesozoic era, Africa was still part of the Pangea supercontinent and had a relatively common fauna with it, dominated by theropods, prosauropods and primitive ornithischian dinosaurs (by the end of the Triassic).

Late Triassic fossils are found everywhere in Africa, but are more common in the south than in the north of the continent. As is known, the time line separating the Triassic from the Jurassic period was drawn according to the global catastrophe with the mass extinction of species (Triassic-Jurassic extinction), but the African layers of this time remain poorly understood today.

Early Jurassic fossil deposits are distributed similarly to those of the Late Triassic, with more frequent outcrops in the south of the continent and fewer deposits towards the north. During the Jurassic period, such iconic groups of dinosaurs as sauropods and ornithopods increasingly spread across Africa. Paleontological layers of the middle Jurassic in Africa are poorly represented and also poorly studied.

Late Jurassic strata are also poorly represented here, with the exception of the impressive collection of Jurassic Tendeguru fauna in Tanzania, whose fossils are very similar to those found in the paleobiotic Morrison Formation in western North America and date from the same period.

In the middle of the Mesozoic, about 150-160 million years ago, Madagascar separated from Africa, while remaining connected to India and the rest of Gondwana. Fossils from Madagascar have included abelisaurs and titanosaurs.

In the early Cretaceous, a part of the land that made up India and Madagascar separated from Gondwana. In the Late Cretaceous, the divergence of India and Madagascar began, which continued until the modern outlines were reached.

Unlike Madagascar, the African mainland was tectonically relatively stable throughout the Mesozoic. And yet, despite the stability, significant changes occurred in its position relative to other continents as Pangea continued to fall apart. By the beginning of the Late Cretaceous, South America separated from Africa, thus completing the formation of the Atlantic Ocean in its southern part. This event had a huge impact on global climate by changing ocean currents.

During the Cretaceous, Africa was inhabited by allosauroids and spinosaurids. The African theropod Spinosaurus turned out to be one of the largest carnivores that lived on Earth. Among the herbivores in the ancient ecosystems of those times, titanosaurs occupied an important place.

Fossil deposits from the Cretaceous are more common than those from the Jurassic, but often cannot be radiometrically dated, making their exact age difficult to determine. Paleontologist Louis Jacobs, who has spent considerable time fieldwork in Malawi, argues that African fossil deposits "need more careful excavation" and are bound to prove "fertile ... for scientific discoveries."

Climate

During the last 1.1 billion years in the history of the Earth, there have been three successive ice age-warm cycles, called the Wilson cycles. Longer warm periods were characterized by a uniform climate, a greater diversity of flora and fauna, and a predominance of carbonate sediments and evaporites. Cold periods with glaciations at the poles were accompanied by a decrease in biodiversity, terrigenous and glacial sediments. The reason for the cyclicity is considered to be the periodic process of connecting the continents into a single continent (Pangaea) and its subsequent disintegration.

The Mesozoic era is the warmest period in the Phanerozoic history of the Earth. It almost completely coincided with the period of global warming, which began in the Triassic period and ended already in the Cenozoic era with a small ice age which continues to this day. For 180 million years, even in the polar regions there was no stable ice cover. The climate was mostly warm and even, without significant temperature gradients, although there was climatic zoning in the northern hemisphere. A large amount of greenhouse gases in the atmosphere contributed to the even distribution of heat. The equatorial regions were characterized by a tropical climate (the Tethys-Pantalassa region) with average annual temperature 25-30°C. Up to 45-50°N the subtropical region (Peritethys) extended, then the moderately warm boreal belt lay further, and the polar regions were characterized by a moderately cool climate.

The Mesozoic had a warm climate, mostly dry in the first half of the era and humid in the second. Slight cooling in the late Jurassic and the first half of the Cretaceous, a strong warming in the middle of the Cretaceous (the so-called Cretaceous temperature maximum), at about the same time the equatorial climatic zone appears.

Flora and fauna

Giant ferns, tree horsetails, and club mosses are dying out. In the Triassic, gymnosperms, especially conifers, flourish. In the Jurassic, seed ferns die out and the first angiosperms appear (then represented only by tree forms), which gradually spread to all continents. This is due to a number of advantages - angiosperms have a highly developed conducting system, which ensures the reliability of cross-pollination, the embryo is supplied with food reserves (due to double fertilization, a triploid endosperm develops) and is protected by shells, etc.

In the animal kingdom, insects and reptiles flourish. Reptiles occupy a dominant position and are represented by a large number of forms. In the Jurassic period, flying lizards appear and conquer the air. In the Cretaceous period, the specialization of reptiles continues, they reach enormous sizes. Some of the dinosaurs weighed up to 50 tons.

The parallel evolution of flowering plants and pollinating insects begins. At the end of the Cretaceous, cooling sets in, and the area of ​​near-water vegetation is reduced. Herbivores are dying out, followed by carnivorous dinosaurs. Large reptiles are preserved only in the tropical zone (crocodiles). Due to the extinction of many reptiles, a rapid adaptive radiation of birds and mammals begins, occupying the vacant ecological niches. In the seas, many forms of invertebrates and sea lizards are dying out.

Birds, according to most paleontologists, evolved from one of the groups of dinosaurs. The complete separation of arterial and venous blood flow determined their warm-bloodedness. They spread widely over land and gave rise to many forms, including flightless giants.

The emergence of mammals is associated with a number of large aromorphoses that arose in one of the subclasses of reptiles. Aromorphoses: a highly developed nervous system, especially the cerebral cortex, which provided adaptation to the conditions of existence by changing behavior, moving limbs from the sides under the body, the emergence of organs that ensure the development of the embryo in the mother's body and subsequent feeding with milk, the appearance of a coat, complete separation of circulatory circles, the emergence of alveolar lungs, which increased the intensity of gas exchange and, as a result - general level metabolism.

Mammals appeared in the Triassic, but could not compete with dinosaurs and for 100 million years occupied a subordinate position in the ecological systems of that time.

: in 86 tons (82 tons and 4 additional). - St. Petersburg. , 1890-1907.

The Mesozoic era began about 250 and ended 65 million years ago. It lasted 185 million years. The Mesozoic is known primarily as the era of the dinosaurs. These giant reptiles obscure all other groups of living beings. But don't forget about others. After all, it was the Mesozoic - the time when real mammals, birds, flowering plants appeared - that the modern biosphere actually formed. And if in the first period of the Mesozoic - the Triassic, there were still many animals from the Paleozoic groups on Earth that could survive the Permian catastrophe, then in the last period - the Cretaceous, almost all those families that flourished in the Cenozoic era were already formed.

In the Mesozoic, not only dinosaurs arose, but also other groups of reptiles, which are often mistakenly considered dinosaurs - aquatic reptiles (ichthyosaurs and plesiosaurs), flying reptiles (pterosaurs), lepidosaurs - lizards, among which were aquatic forms - mosasaurs. Snakes originated from lizards - they also appeared in the Mesozoic - the time of their occurrence is generally known, but paleontologists argue about the environment in which this happened - in water or on land.

Sharks flourished in the seas, they also lived in freshwater reservoirs. Mesozoic - the heyday of two groups cephalopods- ammonites and belemnites. But in their shadow, the nautiluses, which arose in the early Paleozoic and still exist, lived well, the squids and octopuses familiar to us arose.

In the Mesozoic, modern mammals arose, first marsupials, and then placental. In the Cretaceous period, groups of ungulates, insectivores, predators and primates already stood out.

Interestingly, modern amphibians - frogs, toads and salamanders - also arose in the Mesozoic, presumably in the Jurassic period. So, despite the antiquity of amphibians in general, modern amphibians are a relatively young group.

Throughout the Mesozoic, vertebrates sought to master a new environment for themselves - air. The reptiles were the first to fly - first small pterosaurs - rhamphorhynchus, then larger pterodactyls. Somewhere on the border of the Jurassic and Cretaceous, reptiles rose into the air - small feathered dinosaurs capable, if not of flight, then certainly of planning, and the descendants of reptiles - birds - enantiornis and real fan-tailed birds.

A real revolution in the biosphere occurred with the advent of angiosperms - flowering plants. This entailed an increase in the diversity of insects that became pollinators of flowers. The gradual spread of flowering plants has changed the face of terrestrial ecosystems.

The Mesozoic ended with the famous mass extinction, better known as the "extinction of the dinosaurs." The reasons for this extinction are not clear, but the more we learn about the events that took place at the end of the Cretaceous, the less convincing the popular hypothesis of a meteorite catastrophe becomes. The biosphere of the Earth was changing and the ecosystems of the Late Cretaceous were very different from the ecosystems of the Jurassic period. Great amount species died out throughout the Cretaceous period, and not at all at its end - but they simply did not survive the catastrophe. At the same time, there is evidence that in some places a typical Mesozoic fauna still existed at the very beginning of the next era - the Cenozoic. So for the time being, it is not possible to unambiguously answer the question about the causes of the extinction that occurred at the end of the Mesozoic. It is only clear that if some kind of catastrophe happened, it only pushed the changes that had already begun.

I present to your attention a small collection of fossilized mineralized wood that I have formed over many years of gathering. Something was found by me, something was donated (to all those who gave low bow and health, may the hand of the giver not be impoverished), something was bought. It should be said right away that wood appeared a very long time ago. The earliest of known to science fossil woody plants were discovered in 2011 in the Canadian province of New Brunswick, where between 400 and 395 million years ago... >>>