Animal and plant world of the Triassic period. Mesozoic

Mesozoic era.

Triassic.

The Triassic period on Earth lasted about 45 million years. Approximately 220 million years have passed from its beginning to the present day. In the Triassic, land prevailed over the sea. There were two continents. Merged between the North Atlantic and Asian continents formed the Northern land. In the southern hemisphere lay the former Gondwana. Asia joined with Australia and New Zealand. All of Southern Europe, the Caucasus and the Crimea, Iran, the Himalayas and North Africa were flooded by the Tetke ocean. Large mountain ranges did not reappear at this time, but the mountains that had formed in previous periods were still high. There were frequent volcanic eruptions. The climate of the Triassic period was harsh and dry, but warm enough. Deserts in the Triassic are numerous.

Of the plants, gymnosperms noticeably predominated: sago, coniferous and ginkgo. Of the seed ferns, glossopteris continued to exist. At the end of the period, peculiar ferns appeared, especially numerous in the subsequent Jurassic period, the leaves of which, in terms of venation, resembled the leaves of seed plants. Triassic horsetails are much closer to modern horsetails than Paleozoic ones.

Great changes have taken place in the life of the inhabitants of the continents. The predominance of land over the sea, which began in the Permian period, and the progressive drying of many fresh water bodies in the Triassic period, led to the fact that many freshwater fish now moved to the seas, and only lungfish, close to the present, still lived in the surviving freshwater basins. At the end of the Triassic, the stegocephalians became extinct. These were the last representatives of the labyrinth-toothed stegocephalians, so named because the enamel on their teeth had a complex folded structure. All stegocephalians, fleeing from the dry climate and from competition with reptiles, became aquatic, and some even moved to live in the sea. Most of them were very large animals. For example, in Mastodonsaurus, the length of the skull reached 1 m.

At the beginning of the Triassic period, the direct ancestors of modern frogs lived. These protobatrachus are small, 10 cm long, animals, in general structure, they are more like toads than real frogs. Their skin is bumpy, their hind legs are more adapted for swimming than for jumping.

Reptiles have changed especially; whole skulls finally died out. In the second half of the period, the first turtles appeared, which, unlike modern ones, still had teeth in the sky, while the jaws were dressed with a horny beak.

In the Triassic period, they developed intensively, but at the end of it the last animal-like reptiles had already died out. Of these, herbivorous and already completely toothless stahleckers reached the size of a large rhinoceros. The smaller size was a predatory belezodont about 1.5 m.

Particularly interesting are the small animal-like reptiles Ictidosaurs, close to mammals. So, caromis, an animal the size of a rat, is already a real mammal in the structure of its skull, and only additional bones in its lower jaw indicate that this animal is still a reptile.

Of the other reptiles in the Triassic period, the trunk-headed ones developed, the closest relatives of the modern New Zealand tuatara, which, although similar to ordinary lizards, differ from them in their structure. Tuatara in its structure still retains many ancient features. In her skull there are two temporal (zygomatic) arches, and not one, like in lizards. Her upper jaw hangs down in the form of a small beak. The teeth on the jaws do not sit in separate cells, but in a common groove. In addition to the usual ribs, "abdominal ribs" also develop on the belly. The biconcave vertebrae resemble the vertebrae of fish. Among the trunkheads in the Triassic lived stenaulorhynchuses - large burrowing animals, possibly feeding on roots. In the seas, along the coasts of the continents, there were long-snouted proboscis - fighters of sea mollusks. In a place with them, several resembling sea ​​turtles placodonts, in which real millstones for crushing shells formed in the sky instead of small teeth. Related to placodonts, notosaurs also led an aquatic lifestyle. These long-necked animals could still use their paws (flippers) to walk on the ground. Plesiosaurs, common marine reptiles of the following periods, evolved from notosaurs. In northern waters, the first fish lizards, or ichthyosaurs, appeared. They were not yet as well adapted to swimming in the sea as their descendants, in which the tail became like a fish. The most remarkable thing is that ichthyosaurs did not lay eggs like ordinary reptiles, but gave birth to live young, like mammals. From the Triassic, the flowering of a group of cellular reptiles began. The most ancient forms of them were relatively small carnivores. Instead of the usual movement on four legs, these animals adapted to walking on two legs, and therefore their hind legs became much longer than their front ones. Such was Saltoposuchus, an animal larger than 1 m. By the end of the Triassic, some cellular reptiles switched to an aquatic lifestyle. They again began to walk on four legs and in appearance somewhat resembled crocodiles, which were still absent at that time. The length of such a crocodile-like prestosuchus was at least 5 m. The first dinosaurs, not yet very large in size, appeared mainly on the Northern land. Some of them were not small, up to 1m in length, and led a predatory lifestyle. They walked on their hind legs, which were longer than their front ones. In some ways, dinosaurs resembled birds: the bones of their skeleton were hollow, filled with air, and the first toe on the hind legs was turned back.

Other dinosaurs, such as Plateosaurus, were much larger, reaching 6 m in length. The difference in the structure of the front and hind legs is small, their teeth are blunt. These were the ancestors of the herbivorous giants of the Jurassic period.

It is not surprising that with the abundance of animal-like reptiles in the Triassic, we also find here real mammals. The most ancient mammal known to us, the size of a marmot, is called the tritylodont. It belongs to the group of many tubercular mammals, so called because they had numerous tubercles on their molars in two or three rows. They didn't have fangs. One pair of incisors in the upper jaw and a single pair in the lower were enlarged. Many tuberculate teeth ate plant food. They probably still laid eggs, and did not give birth to live Cubs, as well as modern Australian monotreme mammals: platypus and echidna. Modern egg-laying mammals are toothless, but the embryos of the platypus have the rudiments of teeth of a multi-tubercular type. Therefore, many tuberculates are considered the closest relatives of the Australian monotremes, which still retain many features characteristic of reptiles.

At the bottom of the Triassic sea lived numerous six-ray corals, close to modern ones. Bivalves and gastropods were abundant, replacing brachiopods. Often came across new sea ​​urchins and lilies. But numerous ammonites reached a special diversity in this period. At the same time, the first belemnites appeared - animals close to modern cuttlefish, also related to cephalopods. Under their skin, they had a calcareous skeleton in the form of a plate ending in a sharp spike. This spike is usually preserved as a fossil and is called the "devil's finger".

In the sea, in addition to shark fish, quite a lot of bony fish already lived, whose ancestors moved here from fresh water. met here lobe-finned fish and relatives of modern sturgeon fish, as well as armored pikes and silt fish North America. In terms of the structure of the scales, tail and internal organs, these fish still differed from real ones. bony fish.

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The Triassic period began 250 million years ago and ended 200 million years ago. The Permian-Triassic extinction wiped out 90% of the planet's marine species and about 70% of its terrestrial species. However, the planet did not become a desert. The remaining species continued to diversify and fill newly discovered ecological niches. This led to the emergence of many new animal species, including the first dinosaurs and small mammals.

Pangea was a giant supercontinent at the beginning of this period, but tectonic forces began to roll the continent around. By the end of this period, Pangea had split into two separate supercontinents: the supercontinent Laurasia in the northern hemisphere and the supercontinent Gondwana in the southern hemisphere. During these times the climate was dry and hot, and there were probably almost no glaciers. Scientists believe that the polar regions were not covered by ice caps at all, and the climate was temperate and humid, which allowed animals such as reptiles to spread over large areas.

With regard to life during this time, scientists distinguish three different categories: animal species left over from a global extinction event that continued to evolve during this period; new species of life emerged a short time appeared but suddenly died out, and there were those groups of life that not only succeeded, but continued to dominate the rest of the era.

The terrestrial flora included ferns, horsetails, glossopterids, ginkgophytes, lycophytes, and cyclodophytes. In the southern hemisphere, seed ferns called Glossopteris spread, and the northern hemisphere was invaded by Bennettitales, coniferous trees and ferns. In the ocean, corals continued to develop and eventually became similar to today's corals - forming massive coral reefs on the ocean floor. Marine reptiles, including nasosaurs, pachyplerosaurs, and sauropterygia flourished. Ichthyosaurs were particularly successful in dispersing throughout the world's oceans and eventually reached gigantic proportions by the end of this period. The fish and ammonites that were able to survive the last extinction event also continued to thrive.

There were also several groups of fauna or flora that arose during the Triassic period and became dominant during this time. One such group was the Temnospondylia. They were one of the most large groups amphibians that appeared during the Carboniferous and were able to survive extinction. These included offshoots: stereospondyls, tupilacosaurs, mastodosaurs, microfoli, and tabanchua. The therapods became another successful group. Therapods appeared during the Triassic and developed well during this period. Etosaurs were another group that developed successfully during this period. Unfortunately, they became extinct during the extinction event that occurred at the end of this period.

At the end of the Triassic, there was mass extinction, known as the Triassic-Jurassic extinction event. This mass extinction killed almost a quarter of all marine families and may have killed off half of all marine genera. Majority marine reptiles ceased to exist - with the exception of plesiosaurs, ichthyosaurs and conodonts. Although molluscs, brachiopods, and gastropods were not completely wiped out, their populations suffered greatly. Several species of reptiles, synapsids, krutrarsans, labyrinthine amphibians and many primitive dinosaurs were destroyed. However, some of the species were able to adapt and continued to dominate during the Jurassic.

These mass extinctions at the end of the Triassic period vacated many ecological niches. This not only allowed dinosaurs to expand their habitat, but also to thrive. Thanks to open ecological niches, dinosaurs increased in size, their population increased, their species became more diverse. Thus began the age of the dinosaurs. Conifers and Cycads will continue to dominate the next period as well.

Scientists are not sure what caused this extinction event in late period, but many believe it is due to massive volcanic eruptions that coincided with the breakup of the supercontinent Pangea. However, not all scientists share this opinion. Other scientists believe that this extinction was caused by an asteroid impact that created the crater that now contains the Manicouagan reservoir in Quebec, Canada.

From 248 to 213 million years ago.
The Triassic period in the history of the Earth marked the beginning mesozoic era, or "era of middle life". Before him, all the continents were merged into a single giant supercontinent Pangea. With the onset of the Triassic, Pangea began to gradually split. The climate in those days was even throughout the globe. Even at the poles and at the equator weather were much more similar than today. Toward the end of the Triassic, the climate became drier. Lakes and rivers began to dry up quickly, and vast deserts formed in the interior of the continents.
When the continents joined together during the Permian period, forming the supercontinent Pangea, huge land masses crawled on top of each other and swallowed up a significant part of the coast of the World Ocean. Then, during the Triassic period, the climate warmed up, and many of the surviving shallow seas dried up, and the remaining water became very salty. Many old forms marine life disappeared, and new species of animals took their place.

The rise of invertebrates.

New mollusks, such as oysters, appeared in the seas. They burrowed into the bottom sand, passed water through their shells and filtered out food particles from it. There are also many new
gastropods (snails and their relatives). With the lowering of the water level in the shallow seas, their rocky shores became more and more exposed. New types of mollusks, such as limpets and littorinas, found shelter here. There were also new varieties of corals, shrimp and lobsters.
In the Triassic, the first "real" sea urchins, similar to modern ones, also appeared. Ammonites still lived in the seas. At the end of the Triassic, they almost all died out, and those who survived "lasted" until the Jurassic, when their new heyday came.

During the Triassic period, it was hot and dry inside the continents. There were vast barren deserts where there were very few plants. However, near the coast came across fertile land, rich in all kinds of vegetation.
1 Lystrosaurus
2 rhynchosaurus
3 ginkgo
4 araucaria
5 yew
6 cycad
7 tree fern
8 bennettit
9 club
10 horsetail

From sharks to "fishing rods".

Farther from the coast, the most highly organized fish species lived in the open sea. sharks and bony fish disputed each other's booty. Over time, they developed jaws capable of chewing through the shells of crabs and the shells of mollusks like mussels.
The largest predators of the Triassic seas were newly emerged aquatic reptiles. Lizard-like nothosaurs fished with their sharp teeth. Dolphin-like ichthyosaurs could catch up with any prey due to their outstanding speed qualities. Large placodonts, similar to newts, crawled along the seabed, looking for shells, and then crushed them with powerful flat teeth.
The tanystropheus had a long and thin neck, twice as long as its torso. It was a terrestrial animal and probably used its graceful neck as a fishing rod. Standing at the water's edge, the tanystropheus could reach out to fish that swam underwater at a considerable distance from the shore.

Cynognathus, a representative of cynodonts ("dog-toothed" reptiles). It was a strong wolf-sized animal with many of the characteristics of a mammal. Scientists have no doubt that cynognathus had hair: when studying its fossil remains, pits were found on its muzzle, from which a mustache grew. This means that it is possible that these animals were warm-blooded, because the hairline has so far been found only in warm-blooded mammals.
Triassic herds.

At the beginning of the Triassic period, the animal world was the same throughout the entire territory of the earth's land. Various species could freely spread throughout Pangea, because there were no large water barriers in their path. Many animals that lived on Earth during the Permian period became extinct by the beginning of the Triassic, possibly due to
climate change. But some of the animal-like reptiles still survived, and other species in large numbers. Huge herds of herbivorous listrosaurs basked in the silt along the banks of lakes and rivers. These were real "behemoths" of the Triassic world. Their fossils have been found in places as far apart as China, India, South Africa, and even Antarctica. In the early Triassic, the first frogs foraged side by side with them. Later they were joined by the first land and aquatic turtles and also crocodiles. Very soon, aquatic turtles and crocodiles invaded warm seas. There they quickly multiplied and spread throughout the oceans.

The first dinosaurs were small, slender animals. At first, many of them looked more like birds than dinosaurs. The saltop ("leaping foot") was no larger than a cat, and the halticosaurus reached almost 6 m from head to tail. Between these two extremes, there were many animals of various sizes.
"Dog-toothed" and "ruling" reptiles.

On land, there were still cynodonts ("sooakozubye") - sharp-legged predatory reptiles that attacked herds of sluggish herbivorous animals. However, there was also a new group reptiles - it is called archosaurs, that is, "ruling reptiles." The first archosaurs were small animals that hunted small game along the banks of lakes and rivers. Subsequently, much larger animals developed from them.
In the middle of the Triassic, another group of reptiles akin to the archosaurs arose. These were herbivorous rhynchosaurs, that is, "beaked reptiles." Their muzzle ended in a rather strange beak, which they used as tongs when grabbing food. Their jaws and teeth were well adapted for cutting and chopping hard plants. When the mouth of Rhynchosaurus was closed, the lower jaw fit exactly into the groove of the upper jaw, like a penknife when it is folded and the blade is inserted into the handle.

The lizard-like reptile Icarosaurus lived in the early Triassic in North America. Icarosaurus had wings, so to speak, with variable geometry. They were formed by patches of skin tightly stretched over long ribs. When Icarosaurus climbed trees, it folded its wings along its body. And during the flight, its ribs instantly moved apart and the wings straightened in both directions. They acted as a parachute, on which the animal smoothly descended to the ground.
From thecodonts to dinosaurs.

Toward the end of the Triassic period, many land animals that appeared at its beginning became extinct. Their place was taken by new reptiles that developed during the Triassic. Approximately 225 million years ago, a group of reptiles arose, which were called thecodonts ("mesh-toothed"). At first they were clumsy squat animals, a bit like crocodiles. They led an aquatic lifestyle and swam with the help of a powerful tail, while rowing with their hind legs, which were much larger than their front ones. When the early tecodonts emerged from the water onto land, their strong hind legs quickly adapted to walking on hard ground.
Thecodonts soon became excellent walkers and runners. Most of the time they moved on land on four legs. However, they had the ability to turn into true sprinters. To do this, thecodonts took a kind of "starting posture": they leaned back, leaning on their overdeveloped hind limbs, and rushed forward on two legs, balancing on the run with their long tail. Over the next 20 million years, thecodonts evolved into the first dinosaurs on Earth.

This diagram shows internal structure nautilus. It is possible that ammonites also had a similar internal structure.
Two more major breakthroughs.

At the end of the Triassic period, two more important events occurred in the evolution of life on Earth. One of them happened on land and was marked by the appearance of the first mammals. The second occurred in the air and was associated with the advent of pterosaurs ("winged reptiles").

This typical ammonite fossil is a flat, twisted shell with a well-defined spiral shape. The surface of the shell is dotted with patterned ribs "pointing to the places where the partitions used to be. Looking at the petrified ammonite, it is difficult to imagine that these are the remains of an animal - close relative modern octopus and squid. However, if we compare it with another living cephalopod, the nautilus, this relationship immediately becomes apparent.
.Pioneers of aeronautics.

Some vertebrates have already tried to take to the air. One of the "pioneers" was a small lizard that lived in the Permian period and was named by scientists Wesheltisaurus. However, she did not have real wings. She glided from tree to tree on a kind of webbed wing stretched between impossibly long ribs. Pterosaurs improved on this design and became the first vertebrates to achieve full-fledged flight, being themselves heavier than air. They developed a completely different wing structure that allowed them to fly much better than all their predecessors.

Amazing ammonites

Ammonites, which first appeared on Earth in the Devonian period, are the most studied and most common marine fossils. They belong to the group of cephalopods and, therefore, are the predecessors of modern octopuses and squids. Ammonites reached their peak in terms of their abundance and diversity in the Permian period. Then 245 million years ago, at the end of this period, they almost completely disappeared in a mass extinction. But getting rid of the ammonites was not so easy. Some of them managed to survive until the Triassic period and, thanks to their propensity for long-distance wanderings across the ocean, soon spread again throughout the world.
By the middle of the Mesozoic, they reached a new peak of evolutionary prosperity. Ammonites were so common in the Mesozoic seas, and their fossils are found in such abundance in the rocks of that era, that they played a very important role in developing a system for identifying (identifying) all marine deposits of the Mesozoic era. Yet such prosperity could not last forever, and in the end Cretaceous all ammonites suddenly disappeared from the face of the Earth - along with many other marine animals, including belemnites, pliosaurs, ichthyosaurs and plesiosaurs.
From straight shells to swirling
The first cephalopods, the so-called nautilo-ideas, had long conical shells. Inside the shells were gas chambers separated by partitions. Nautiloids developed a very primitive way of drawing in and pushing water, and they used the jet ejected to create a kind of jet thrust. In the millions of years since then, cephalopods, including the ammonites, have perfected this method and made it their main mode of transportation. Throughout Paleozoic era(570-225 million years ago) nautiloids were the most common marine predators. Then new, more highly organized cephalopods appeared, including ammonites, in which a shell of a completely different shape developed - curled, flat and often with a rather complex relief pattern.
Partitions and seams
Like modern nautilus, the ammonite shell was broken up into a series of internal chambers. Each of them was separated from the next by a partition. The animal itself was placed in the latest of the newly formed chambers. The places where the septa were attached to the shell are often clearly visible on ammonite fossils. They are called seam lines. Such lines form quite complex patterns on the shells of ammonites that lived in the Jurassic and Cretaceous periods. Scientists use these patterns to classify the vast number of ammonite fossils discovered over the years.
Ballast and buoyancy
The ammonite shell served as a ballast (stabilizing) mechanism, just as modern nautiluses use their own multi-chamber shells. The animal filled the free chambers with water and emptied them again with the help of a special organ - it is called a siphon. Pumping and pumping out water, the ammonite regulated the buoyancy of its own body, as submarines do. When the animal wanted to dive deeper, it filled its "ballast compartments" with water. When it wanted to float to the surface or simply rise higher, it emptied them.
The disappearance of ammonites
The incredible abundance of ammonite fossils turned out to be somewhat misleading, forcing scientists at one time to draw not entirely correct conclusions about their distribution in past eras. Until very recently, experts believed that ammonites inhabited all primitive seas without exception. However, then it was found that not all of their varieties lived all over the globe. At different types there were different areas, which, in all likelihood, was due to a number of physical factors, for example, with the temperature of the water or with the percentage of salt in the drink (salinity). The displacement of the continents at the end of the Cretaceous period led to grandiose climate change and general transformation (transformation) natural environment affecting the oceans as well. Probably, the ammonites this time failed to adapt to the new living conditions and completely died out.

The degree of twisting of ammonite shells is different. This was usually in the form of a single spiral, but later some species developed partially untwisted shells, a bit like a question mark with whorls. The shells of even later varieties looked like snail shells in shape.

Triassic

The Triassic was a time of extensive land development. Only in some places did the sea advance on land: in Caspian lowland, on the plains of Germany, in the north - in the region of the Svalbard islands. The sea also expanded in the center southern mainland Gondwana - where the Mozambique Channel is now. It was the beginning of the formation of the Indian Ocean depression in the Gondwanan mainland.

Hot clouds of volcanic ash swirled over the Siberian platform: numerous volcanoes sparkled from the middle reaches of the Angara to the northern outskirts of the platform, from the Lena in the east to the Yenisei in the west. Throughout this vast area, volcanic rocks have intruded into ancient Paleozoic strata.

For tens and hundreds of kilometers stretch ancient cracks filled with solidified magma that rose from the depths of the earth over 150 million years ago.

In many places we find layers of the Triassic sedimentary rocks. These are mainly variegated marls, sandstones and limestones. They occur in Siberia - in the Verkhoyansk-Okhotsk mountains and in the Ussuri river basin; come out in the lower Volga region, near Lake Baskunchak, in Transcaspia, in the Crimea, in the Caucasus.

On the Crimean coast, the thickness of Triassic sandstones and shale reaches several thousand meters.

The layers of this period contain numerous remains of animals and plants. They tell us about the life that once boiled in the seas and on land of the Triassic continents.

Various types of mollusks filled the shallow waters of the seas. Algae covered the bottom with a dense green carpet. Sea urchins crawled in their thickets.

The first belemnites appeared - mollusks with an inner shell. Their elongated bodies quickly swam in the clear water, really resembling an arrow (“belemnon” in Greek means “arrow”). Belemnites moved with the help of a jet of water, which they threw out with force, thus receiving a push in reverse side. The inner shell of the belemnites was dressed on top with a skin cover. Parts of this shell have survived to our time. On the banks of rivers, in ravines, and in other places where Mesozoic layers protrude to the surface, smooth stone sticks, pointed at one end, are often found now. In the people they are called thunder arrows or "devil's fingers". These sticks are the fossilized remains of belemnites, cone-shaped processes from the inside of their shells.

Belemnite.

During the Triassic, there were again changes in climatic conditions on the ground.

Young mountain ranges that formed along the ocean coasts and fenced off the land from moist sea winds created conditions for a sharp continental climate. Tree-like ferns and horsetails began to gradually disappear, the land was covered with cycads and conifers, better adapted to changing climatic conditions.

Reptiles found abundant food in the forests. They have reached a significant diversity, increased in size.

... What a massive bone lies under the glass of the showcase in the museum hall, where the fossil remains of the Triassic time are collected! What animal did it belong to?

Our "time machine" instantly takes us to the edge of the Triassic forest, through which a large river flows.

Tree-like horsetails grow in small groups near the water. They are already living out their lives, they were replaced by forests of primitive coniferous gymnosperms. Spreading leaves of cycads hung over the water.

A huge amphibian lies on the sand, lazily spreading its paws, lowering the lower part of its wide, flat head into the water.

Near the horsetails, a reptile with a long tail and disproportionately small front paws lurked, lying in wait for prey. In its appearance, it resembles a large lizard standing on its hind legs. This is a cellular lizard - the ancestor of birds and "terrible lizards" - dinosaurs that will appear on Earth after millions of years. Scientists called him "cell-toothed" because each tooth was in a special cell.

In the middle of the clearing, a plateosaurus walking on its hind legs froze in a wary pose. Its massive body resting on the tail reaches 5 meters in length. Turning his small head on a long neck to the river, he looks at the crocodile-like belodont crawling out of the water onto the shore ...

Plateosaurus at the edge of the Triassic forest.

The Triassic period lasted about 30 million years - the time of cephalopods, primitive conifers and pangolins. Cold-blooded reptiles - lizards - inhabited the coasts of the seas, forest thickets, began to penetrate into desert spaces in the depths of the continents.

Millions more years will pass - and the lizards will become the rulers of the Earth. They will take possession of all the land, the waters of the seas, they will rise into the air. But for the time being, they have to be content with the rather modest role that they had to play among many other animals that lived on Earth in the Triassic period of its history.

From the book Breeding Dogs by Harmar Hillery

"Furious period". Most dogs go through a frenetic period. In dwarf breeds, it is barely noticeable; in middle-aged breeds, this period can be funny. But when it comes to puppies large breeds, in particular such as bloodhound and mastiffs, violent period

From the book Dogs and their breeding [Breeding dogs] by Harmar Hillery

Furious Period Most dogs go through a furious period. In dwarf breeds, it is barely noticeable; in middle-aged breeds, this period can be funny. But when it comes to puppies of large breeds, such as Bloodhound and Great Danes in particular, the furious period

From the book Breeding Dogs author Sotskaya Maria Nikolaevna

Neonatal period or neonatal period In the first minutes after birth, the respiratory center is activated, which, until the end of life, regulates the supply of oxygen to the body and the removal of carbon dioxide, and the lungs expand with the first breath. Respiratory rate

From the book Journey to the Past author Golosnitsky Lev Petrovich

Transitional period The second period is a transitional period (21–35 days). Its beginning marks the emergence of an interest in meat and other solid foods. At the same time, the puppy develops chewing movements - until now, the only response to any irritation of the oral cavity was sucking. AT

From the book Before and After Dinosaurs author Zhuravlev Andrey Yurievich

Juvenile period The fourth period of puppy development begins after 12 weeks. During this period, the formation of typological abilities takes place. Before it starts, all puppies behave very similarly - they are contact, playful, easily excitable and practically do not have a bright

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Cambrian period In many places, sedimentary Cambrian rocks, formed over 400 million years ago, come to the surface of the earth. These are mainly sandstones, limestones and shale - a hard rock of dark gray or black color,

From the author's book

Silurian period The ancient history of England is captured in the name of this period. Fierce wars waged Ancient Rome seeking to enslave other peoples. The Celtic tribe of the Silures, led by the brave leader Caradoc, staunchly fought back from the Roman conquerors. But

From the author's book

Devonian period Already many hundreds of millions of years have passed since life arose on Earth in the form of microscopic lumps of protein matter. Countless generations of living beings have succeeded each other. A rich and diverse world of plants and animals inhabits the waters

From the author's book

Carboniferous period towards the end Devonian period flowing waters washed away, strongly smoothed the mountain ranges that rose along the ocean coasts. Wet sea ​​winds began to freely sweep over the continents. The sea began to attack the land again. shallow

From the author's book

Permian period At the end of the last century, much in the history of life on Earth was still unclear and mysterious. One of the great mysteries was the Permian - following the Carboniferous - period, the last period of the ancient era. Scientists have established a slender

From the author's book

Jurassic ... The night was coming to an end. The narrow crescent of the moon disappeared behind the patterned wall of the forest, and the bright path that trembled on the waves went out. The pre-dawn breeze brought with it the coolness of the sea. The surf roared monotonously and deafly. But then the sky in the east began to turn pale, turn pink,

From the author's book

Cretaceous period In the lower reaches of the Volga, in the Ukraine near Kharkov and in other places, there are thick layers of white writing chalk. Take a look at a grain of chalk under a microscope. You will see that half of it consists of the smallest shells covered with holes and their fragments. inhabitants

From the author's book

Tertiary period This was one of the most turbulent and eventful periods in the history of the Earth. Alpine mountain building, which began back in the Mesozoic era, manifested itself with extraordinary force. In the roar of earthquakes, in the roar of volcanoes, the mountain ranges of the Alps were born in the Tertiary

From the author's book

Chapter IX From the greatest extinction to the Mesozoic realignment (Triassic, Jurassic and Cretaceous periods: 248 - 65 million years ago) I am an ichthyosaur, plesiosaur, pliosaurus, ferocious; I cut the water; streamlined, silent, fast and light, like a shadow of blue - the toothy blue itself! Bye

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Chapter X Among the tailed, humpbacked and feathered (Triassic, Jurassic periods and the Early Cretaceous era: 248 - 99 million years ago) And the pine, marked by princely grandeur, knows no equal in nobility, and in autumn for many centuries it was not possible to change the color of the needles, all as green as

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Chapter XIII The Planet of the Apes (the end of the Neogene and Quaternary: 5 million years ago - the modern period) Never in its history has humanity been so stuck at a crossroads. One way is hopeless and completely hopeless. The other leads to complete extinction. God give us

The Mesozoic consists of three periods: Triassic, Jurassic, Cretaceous.

in the triassic most of the land was above sea level, the climate was dry and warm. Due to the very dry climate in the Triassic, almost all amphibians disappeared. Therefore, the flowering of reptiles began, which were adapted to drought (Fig. 44). Among plants in the Triassic, strong development reached gymnosperms.

Rice. 44. Various types of reptiles of the Mesozoic era

Of the Triassic reptiles, turtles and tuatara have survived to this day.

The tuatara, preserved on the islands of New Zealand, is a real "living fossil". Over the past 200 million years, the tuatara has not changed much and retained, like its Triassic ancestors, a third eye located in the roof of the skull.

Of reptiles, the rudiment of the third eye is preserved in lizards agamas and batbats.

Along with undoubted progressive features in the organization of reptiles, there was one very significant imperfect feature - unstable body temperature. In the Triassic period, the first representatives of warm-blooded animals appeared - small primitive mammals - tricodonts. They originated from ancient animal-toothed lizards. But tricodonts the size of a rat could not compete with reptiles, so they did not spread widely.

Yura named after a French city located on the border with Switzerland. In this period, the planet is "conquered" by dinosaurs. They mastered not only land, water, but also air. Currently, 250 species of dinosaurs are known. One of the most characteristic representatives of dinosaurs was a giant brachiosaurus. It reached a length of 30 m, weight 50 tons, had a small head, a long tail and neck.

In the Jurassic period, various types of insects and the first bird appear - archeopteryx. Archeopteryx is about the size of a crow. His wings were poorly developed, there were teeth, a long tail covered with feathers. In the Jurassic period of the Mesozoic, there were many reptiles. Some of their representatives began to adapt to life in the water.

The rather mild climate favored the development angiosperms.

Chalk- the name is given because of the powerful Cretaceous deposits formed from the remains of the shells of small marine animals. In this period, angiosperms arise and spread extremely rapidly, gymnosperms are forced out.

The development of angiosperms during this period was associated with the simultaneous development of pollinating insects and insect-eating birds. In angiosperms, a new reproductive organ arose - a flower that attracts insects with color, smell and nectar reserves.

At the end of the Cretaceous, the climate became colder, and the vegetation of the coastal lowlands perished. Together with the vegetation, herbivores died, carnivorous dinosaurs. Large reptiles (crocodile) survived only in the tropical zone.

Under the conditions of a sharply continental climate and a general cooling, warm-blooded birds and mammals received exceptional advantages. The acquisition of live birth and warm-bloodedness were those aromorphoses that ensured the progress of mammals.

During the Mesozoic period, the evolution of reptiles developed in six directions:

1st direction - turtles (appeared in the Permian period, have a complex shell, fused with ribs and breast bones);

5th direction - plesiosaurs (sea lizards with a very long neck, making up more than half of the body and reaching a length of 13-14 m);

6th direction - ichthyosaurs (lizard fish). Appearance similar to fish and whale, short neck, fins, swim with the help of the tail, legs control the movement. Intrauterine development - live birth of offspring.

At the end of the Cretaceous period, during the formation of the Alps, climate change led to the death of many reptiles. During the excavations, the remains of a bird the size of a dove, with the teeth of a lizard, which had lost the ability to fly, were discovered.

Aromorphoses that contributed to the appearance of mammals.

1. The complication of the nervous system, the development of the cerebral cortex had an impact on the change in the behavior of animals, adaptation to the living environment.

2. The spine is divided into vertebrae, the limbs are located from the abdominal part closer to the back.

3. For intrauterine bearing of cubs, the female has developed a special organ. The babies were fed with milk.

4. Hair appeared to preserve body heat.

5. There was a division into a large and small circle of blood circulation, warm-bloodedness appeared.

6. Lungs have developed with numerous bubbles that enhance gas exchange.

1. Periods of the Mesozoic era. Triassic. Yura. Bor. Tricodonts. Dinosaurs. Archosaurs. Plesiosaurs. Ichthyosaurs. Archeopteryx.

2. Aromorphoses of the Mesozoic.

1. What plants were widespread in the Mesozoic? Explain the main reasons.

2. Tell us about the animals that developed in the Triassic.

1. Why is the Jurassic period called the period of the dinosaurs?

2. Disassemble the aromorphosis, which is the cause of the appearance of mammals.

1. In what period of the Mesozoic did the first mammals appear? Why weren't they widespread?

2. Name the types of plants and animals that developed in the Cretaceous period.

In what period of the Mesozoic did these plants and animals develop? Opposite the corresponding plants and animals, put the capital letter of the period (T - Triassic, Yu - Jurassic, M - Cretaceous).

1. Angiosperms.

2. Tricodonts.

4. Eucalyptus.

5. Archeopteryx.

6. Turtles.

7. Butterflies.

8 Brachiosaurs

9. Tuataria.

11. Dinosaurs.