The name of this period speaks for itself, since during this geological time period the conditions were created for the formation of coal and natural gas deposits. However, the Carboniferous period (359-299 million years ago) was also notable for the appearance of new land vertebrates, including the earliest amphibians and lizards. The Carboniferous became the penultimate period (542-252 million years ago). It was preceded by , and , and then it was replaced by .

Climate and geography

The global climate of the Carboniferous period was closely related to its. During the preceding Devonian period, the northern supercontinent Laurussia merged with the southern supercontinent Gondwana, creating the huge supercontinent Pangea, which occupied most of the southern hemisphere during the Carboniferous. This had a marked effect on air and water circulation patterns, resulting in much of southern Pangea being covered by glaciers and a general trend toward global cooling (which, however, had little effect on coal formation). Oxygen made up a much higher percentage of the Earth's atmosphere than it does today, which influenced the growth of terrestrial megafauna, including dog-sized insects.

Animal world:

Amphibians

Our understanding of life during the Carboniferous period is complicated by the Romer Gap, a 15-million-year period of time (360 to 345 million years ago) that has yielded virtually no fossil information. However, we do know that by the end of this rupture, the earliest Late Devonian fish, which had only recently evolved from lobe-finned fish, had lost their internal gills and were on their way to becoming true amphibians.

By the late Carboniferous, such important genus from the point of view of evolution were represented as Amphibamus And Phlegethontia, which (like modern amphibians) needed to lay eggs in water and constantly moisturize their skin, and therefore could not go too far onto land.

Reptiles

The main feature that distinguishes reptiles from amphibians is their reproductive system: reptile eggs can withstand dry conditions better and therefore do not need to be laid in water or wet soil. The evolution of reptiles was driven by the increasingly cold, dry climate of the Late Carboniferous period; one of the earliest identified reptiles Hylonomus ( Hylonomus), appeared about 315 million years ago, and the giant (almost 3.5 meters in length) Ophiacdon ( Ophiacodon) evolved several million years later. By the end of the Carboniferous, reptiles had migrated well to the interior of Pangea; these early discoverers were descendants of archosaurs, pelycosaurs, and therapsids from the subsequent Permian period (archosaurs would go on to give rise to the first dinosaurs almost a hundred million years later).

Invertebrates

As noted above, the Earth's atmosphere contained an unusually high percentage of oxygen during the Late Carboniferous period, reaching an astonishing 35%.

This feature was useful for terrestrials such as insects, which breathed using air diffusion through their exoskeleton rather than using lungs or gills. Carboniferous was the heyday of the giant dragonfly Meganeura ( Megalneura) with a wingspan of up to 65 cm, as well as the giant Arthropleura ( Arthropleura), reaching almost 2.6 m in length.

Sea life

With the disappearance of the distinctive placoderms (plate-skinned fishes) at the end of the Devonian period, the Carboniferous is not well known for its fish, except that some genera of lobe-finned fishes were closely related to the very first tetrapods and amphibians to colonize land. Falcatus, a close relative of the Stethekants ( Stethacanthus), was probably the most famous carboniferous shark, along with the much larger Edestus ( Edestus), which is known for its distinctive teeth.

As in previous geological periods, small invertebrates such as corals, crinoids, and crinoids lived in abundant quantities in Carboniferous seas.

Vegetable world

The dry, cold conditions of the late Carboniferous period were not particularly favorable for flora, but this did not prevent such hardy organisms as plants from colonizing every available one. Carbone witnessed the very first plants with seeds, as well as bizarre genera such as Lepidodendron, with a height of up to 35 m, and the slightly smaller (up to 25 in height) Cigallaria. The most important plants of the Carboniferous period were those that lived in the carbon-rich "coal swamps" near the equator, and millions of years later they formed the vast coal deposits used by humanity today.

Carboniferous or Carboniferous period. Is the fifth period of the era. Lasted from 358 million years ago to 298 million years ago, that is, for 60 million years. To avoid getting confused about eons, eras and periods, use the geochronological scale, which is located, as a visual clue.

Carboniferous received the name “Carboniferous” due to the fact that strong coal formation is found in the geological layers of this period. However, this period is not only characterized by increased coal formation. Carboniferous is also known for the formation of the supercontinent Pangea and the active development of life.

It was in Carboniferous that the supercontinent Pangea appeared, which is considered the largest in size that has ever existed on Earth. Pangea was formed by the union of the supercontinent Laurasia (North America and Eurasia) and the supercontinent Gondwana (South America, Africa, Antarctica, Australia, New Zealand, Arabia, Madagascar and India). As a result of the connection, the old ocean, Rhea, ceased to exist, and a new ocean, Tethys, arose.

The flora and fauna underwent significant changes in the Carboniferous. The first coniferous trees appeared, as well as cycads and cordaite plants. The animal world experienced rapid flourishing and species diversity. This period can also be attributed to the heyday of land animals. The first dinosaurs appeared: primitive reptiles cotilosaurs, animal-like animals (synapsids or theromorphs, considered the ancestors of mammals), herbivorous edaphosaurs with a large crest on their back. Many species of vertebrates appeared. In addition, insects also flourished on land. During the Carboniferous period, dragonflies, mayflies, flying cockroaches and other insects lived. Several species of sharks are found in the Carboniferous, some of which reached 13 meters in length.

Animals of the Carboniferous Period

Arthropleura

Tuditanus punctulatus

Baphetidae

Westlothian

Cotilosaurus

Meganeura

Real-size model of Meganeura

Nautiloids

Proterogyrinus

Edaphosaurus

Edaphosaurus

Eogyrinus

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From 360 to 286 million years ago.
At the beginning of the Carboniferous period (Carboniferous), most of the earth's land was collected into two huge supercontinents: Laurasia in the north and Gondwana in the south. During the Late Carboniferous, both supercontinents steadily moved closer to each other. This movement pushed upward new mountain ranges that formed along the edges of the plates of the earth's crust, and the edges of the continents were literally flooded by streams of lava erupting from the bowels of the Earth. The climate cooled noticeably, and while Gondwanaland "swimmed" across the South Pole, the planet experienced at least two glaciations.

In the Early Carboniferous, the climate over most of the earth's land surface was almost tropical. Huge areas were occupied by shallow coastal seas, and the sea constantly flooded the low-lying coastal plains, forming vast swamps there. In this warm and humid climate, virgin forests of giant tree ferns and early seed plants became widespread. They released a lot of oxygen, and by the end of the Carboniferous, the oxygen content in the Earth's atmosphere almost reached modern levels.
Some trees growing in these forests reached 45 m in height. The plant mass increased so quickly that the invertebrate animals living in the soil simply did not have time to eat and decompose the dead plant material in time, and as a result it became more and more numerous. In the humid climate of the Carboniferous period, this material formed thick deposits of peat. In swamps, peat quickly sank under water and became buried under a layer of sediment. Over time, these sedimentary layers turned into coal-bearing strata
cabbage soup deposits of sedimentary rocks layered with coal formed from the fossilized remains of plants in peat.

Reconstruction of a coal swamp. It is home to many large trees, including sigillaria (1) and giant club mosses (2), as well as dense stands of calamites (3) and horsetails (4), ideal habitat for early amphibians such as Ichthyostega (5) and Crinodon (6). . Arthropods are swarming all around: cockroaches (7) and spiders (8) scurry in the undergrowth, and the air above them is plowed by giant meganeura dragonflies (9) with a wingspan of almost a meter. Due to the rapid growth of such forests, a lot of dead leaves and wood accumulated, which sank to the bottom of the swamps before they could decompose, and over time turned into peat and then coal.
Insects are everywhere

At that time, plants were not the only living organisms that colonized land. Arthropods also emerged from the water and gave rise to a new group of arthro-nodes, which turned out to be extremely viable, insects. From the moment insects first appeared on the stage of life, their triumphal march began, but
planet. Today there are at least a million species of insects known to science on Earth, and, according to some estimates, about 30 million more species remain to be discovered by scientists. Truly our time could be called the era of insects.
Insects are very small and can live and hide in places inaccessible to animals and birds. The bodies of insects are designed in such a way that they easily master any means of movement - swimming, crawling, running, jumping, flying. Their hard exoskeleton is the cuticle (consisting of a special substance - chitin) -
passes into the oral part, capable of chewing hard leaves, sucking plant juices, and also piercing the skin of animals or biting prey.

HOW COAL IS FORMED.
1. The coal forests grew so quickly and lushly that all the dead leaves, branches and tree trunks that accumulated on the ground simply did not have time to rot. In such “coal swamps,” layers of dead plant remains formed deposits of water-soaked peat, which was then compressed and turned into coal.
2. The sea advances on land, forming deposits on it from the remains of marine organisms and layers of silt, which subsequently turn into clay shales.
3. The sea recedes, and rivers deposit sand on top of the shale, from which sandstones are formed.
4. The area becomes more swampy, and silt is deposited on top, suitable for the formation of clayey sandstone.
5. The forest grows back, forming a new coal seam. This alternation of layers of coal, shale and sandstone is called a coal-bearing strata

Great Carboniferous Forests

Among the lush vegetation of the Carboniferous forests, huge tree ferns, up to 45 m high, with leaves longer than a meter, prevailed. In addition to them, giant horsetails, club mosses and recently emerged seed-bearing plants grew there. The trees had an extremely shallow root system, often branching above the surface
soil, and they grew very close to each other. The area was probably littered with fallen tree trunks and piles of dead branches and leaves. In these impenetrable jungles, plants grew so quickly that the so-called ammonifiers (bacteria and fungi) simply did not have time to cause decay of organic remains in the forest soil.
In such a forest it was very warm and humid, and the air was constantly saturated with water vapor. The many creeks and swamps provided ideal spawning grounds for countless insects and early amphibians. The air was filled with the buzzing and chirping of insects - cockroaches, grasshoppers and giant dragonflies with wingspans of almost a meter, and the undergrowth was teeming with silverfish, termites and beetles. The first spiders had already appeared, and numerous centipedes and scorpions were scurrying across the forest floor.

Fragment of a fossilized Aletopteris fern from a coal-bearing strata. Ferns thrived in the damp, humid Carboniferous forests, but they were ill-adapted to the drier climate that developed during the Permian period. When germinating, fern spores form a thin, fragile plate of cells - prothallium, in which male and female reproductive organs are developed over time. Prothallium is extremely sensitive to moisture and dries quickly. Moreover, male reproductive cells, sperm secreted by prothallium, can reach the female egg only through a film of water. All this interferes with the spread of ferns, forcing them to stick to moist habitats, where they are still found today.
Plants of coal swamps

The flora of these huge forests would seem very strange to us.
Ancient clubmoss plants, relatives of modern clubmosses, looked like real trees - 45 m high. Heights of up to 20 m reached the top of giant horsetails, strange plants with rings of narrow leaves growing directly from thick jointed stems. There were also ferns the size of good trees.
These ancient ferns, like their living descendants, could only exist in humid areas. Ferns reproduce by producing hundreds of tiny spores in a hard shell, which are then carried by air currents. But before these spores can develop into new ferns, something special must happen. First, tiny fragile gametophytes (plants of the so-called sexual generation) grow from the spores. They, in turn, produce small calyces containing male and female reproductive cells (sperm and eggs). To swim to the egg and fertilize it, sperm need a film of water. And only then can a new fern, the so-called sporophyte (asexual generation of the plant’s life cycle), develop from the fertilized egg.

Meganeura were the largest dragonflies ever to live on Earth. Moisture-saturated coal forests and swamps provided shelter for many smaller flying insects, which served as easy prey for them. The huge compound eyes of dragonflies give them almost all-round visibility, allowing them to detect the slightest movement of a potential victim. Perfectly adapted to aerial hunting, dragonflies have undergone very little changes over the past hundreds of millions of years.
Seed plants

Fragile gametophytes can only survive in very wet places. However, towards the end of the Devonian period, seed ferns appeared, a group of plants that managed to overcome this disadvantage. Seed ferns were in many ways similar to modern cycads or cyathea and reproduced in the same way. Their female spores remained on the plants that gave birth to them, and there they formed small flask-shaped structures (archegonia) containing eggs. Instead of floating sperm, seed ferns produced pollen that was carried by air currents. These pollen grains germinate into female spores and release male reproductive cells into them, which then fertilize the egg. Now plants could finally colonize the arid regions of the continents.
The fertilized egg developed inside a cup-shaped structure called an ovule, which then developed into a seed. The seed contained reserves of nutrients, and the embryo could quickly germinate.
Some plants had huge cones up to 70 cm long, which contained female spores and formed seeds. Now plants could no longer depend on water, which previously required male reproductive cells (gametes) to reach eggs, and the extremely vulnerable gametophytic stage was excluded from their life cycle.

Warm Late Carboniferous swamps abounded in insects and amphibians. Butterflies (1), giant flying cockroaches (2), dragonflies (3) and mayflies (4) fluttered among the trees. Giant two-legged centipedes feasted in the rotting vegetation (5). Labiopods hunted on the forest floor (6). Eogyrinus (7) is a large amphibian, up to 4.5 m long, which may have hunted like an alligator. And the 15-centimeter microbrachia (8) fed on the smallest animal plankton. The tadpole-like Branchiosaurus (9) had gills. Urocordilus (10), Sauropleura (1 1) and Schincosaurus (12) looked more like newts, but the legless dolichosoma (13) looked a lot like a snake.
Time for amphibians

The bulging eyes and nostrils of the first amphibians were located at the very top of the wide and flat head. This “design” turned out to be very useful when swimming on the water surface. Some of the amphibians may have been lying in wait for prey, half submerged in water - in the manner of modern crocodiles. They may have looked like giant salamanders. These were formidable predators with hard and sharp teeth with which they grabbed their prey. A large number of their teeth are preserved as fossils.
Evolution soon gave rise to many different forms of amphibians. Some of them reached 8 m in length. The larger ones still hunted in the water, and their smaller counterparts (microsaurs) were attracted by the abundance of insects on land.
There were amphibians with tiny legs or no legs at all, something like snakes but without scales. They may have spent their entire lives buried in the mud. Microsaurs looked more like small lizards with short teeth, with which they split the covers of insects.

A Nile crocodile embryo inside an egg. Such eggs, resistant to drying out, protect the embryo from shocks and contain enough food in the yolk. These properties of the egg allowed reptiles to become completely independent of water.
First reptiles

Towards the end of the Carboniferous period, a new group of four-legged animals appeared in the vast forests. Basically, they were small and in many ways similar to modern lizards, which is not surprising: after all, these were the first reptiles on Earth. Their skin, more waterproof than that of amphibians, gave them the opportunity to spend their entire lives out of water. There was plenty of food for them: worms, centipedes and insects were at their complete disposal. And after a relatively short time, larger reptiles appeared and began to eat their smaller relatives.

Everyone has their own pond

The need for reptiles to return to water to reproduce has disappeared. Instead of laying soft eggs that hatched into floating tadpoles, these animals began laying eggs in a hard, leathery shell. The babies that hatched from them were exact miniature copies of their parents. Inside each egg there was a small bag filled with water, where the embryo itself was located, another bag with the yolk, which it fed on, and, finally, a third bag where feces accumulated. This shock-absorbing layer of liquid also protected the embryo from shock and damage. The yolk contained a lot of nutrients, and by the time the baby hatched, it no longer needed a pond (instead of a pouch) to mature: it was already old enough to get its own food in the forest.
rum If you moved them up and down, you could warm up even faster - let's say, like you and I warm up when running in place. These "flaps" became larger and larger, and the insect began to use them to glide from tree to tree, perhaps to escape predators such as spiders.

FIRST FLIGHT
Carboniferous insects were the first creatures to take to the air, and they did this 150 million years before birds. Dragonflies were the pioneers. They soon became the “kings of the air” of the coal swamps. The wingspan of some dragonflies reached almost a meter. Butterflies, moths, beetles and grasshoppers then followed suit. But how did it all start?
In the damp corners of your kitchen or bathroom, you may have noticed small insects called scale insects (right). There is a species of silverfish with a pair of tiny flap-like plates protruding from their bodies. Perhaps some similar insect became the ancestor of all flying insects. Maybe it spread these plates in the sun to quickly warm up in the early morning.

Once upon a time, the waters of the World Ocean covered the entire planet, and the land appeared on its surface as separate islands. Scientists indicate these islands with great accuracy. How? Through coal seams scattered throughout the globe, even in polar countries. Each area where coal is found was then an island, around which the waves of the World Ocean boiled. By the extent of the coal deposits, one can determine the approximate size of the forests that covered the islands. And by the thickness of the coal seams they know how long they grew here. Millions of years ago, these island forests captured enormous reserves of energy from the sun's rays and buried them with them in the stone graves of the Earth.

They did a great job, these primeval forests. Coal reserves around the globe amount to trillions of tons. It is believed that with the extraction of two billion tons per year, humanity will be provided with fossil coals for millennia! And Russia ranks first in the world in terms of coal reserves.

Natural engravings imprinted by nature itself, depicting the vegetation of forests of past periods, have been preserved in the ground. Pieces of coal, shale, and brown coal often contain strikingly clear imprints of plants that are their contemporaries.

Sometimes nature preserved parts of plants in amber; inclusions of animal origin were also found in it. Amber was highly valued in the ancient world as jewelry. Caravans of ships followed him to the shores of the foggy Baltic. But what is amber itself? The Roman writer and naturalist Pliny conveys a touching Greek legend about its origin: the frozen tears of girls, daughters of Apollo, inconsolably mourning the death of their brother Phaethon...

The origin of amber was not known in the Middle Ages either, although the demand for it increased greatly. He used it to make rich monastic rosaries.

The secret of amber was revealed by M.V. Lomonosov: “Amber is a product of the plant kingdom.” This is the frozen resin of coniferous trees that once grew in the places where amber is now mined.

Using a microscope, remains of pollen and spores of ancient plants were discovered in rock layers.

Finds from different layers are compared with each other and with modern plants and thus study the plant world of distant times. “Nature reveals many underground secrets in this way,” - this is how one can say about this in the words of M. V. Lomonosov.

Most often they are not at all similar to our plants, sometimes they resemble them to some extent and yet are sharply different. It was a different plant world, and only sometimes, mainly in tropical countries, are plants found - a living reminder of ancient times.

From the prints it is possible to reconstruct forest landscapes of the Carboniferous period and later. “We can even recreate these landscapes with such completeness,” writes German researcher Karl Müller in the book “The World of Plants. An experience of space botany,” as if nature had handed over to us a collection of all the plants of that time.”

… The forests of the Carboniferous period rose straight out of the water; they occupied low-lying shores and swampy plains inside the islands. Nothing like modern forests of any latitude on earth with their life forms and colors.

In the middle of the Carboniferous period, giant forms of clubmosses developed - lepidodendrons and sigillaria, whose powerful trunks, up to two meters in diameter, reached 20-30 meters in height. They have narrow bristle-like leaves scattered along the trunk. Somewhat lower were giant horsetails - calamites.

Lepidodendrons and sigillaria settled on muddy banks, where other plants without such branched roots with vertical outgrowths for breathing were suffocating.

Real ferns with wide pinnately divided plates - fronds - also appeared. But their position was much more modest than that of club mosses and horsetails. They did not produce such gigantic forms, but they surpassed mosses and horsetails in diversity: from tree-like to delicate herbaceous. Their thin dark brown trunks with thickenings and scars from fallen leaves, overgrown with green mosses, raised bunches of huge, beautifully dissected leaves, like magnificent fans, to the then eternally gloomy sky. Climbing species of ferns entwined the trunks of tree species and mixed below with the grassy cover of ferns.

Above the gentle arch of the green canopy stretched a dark sky with heavy clouds. Frequent showers, thunderstorms, evaporation, warm and even temperatures created conditions extremely favorable for the development of ferns. Luxurious bush-like forms grew under the tree ferns. The soil, where mosses and algae had rotted, was covered with herbaceous ferns. But these forests presented a monotonous and dull picture: only about 800 plant species have been discovered so far, including more than 200 species of ferns.

In prints on coal there are often traces of real trees - cordaites, the ancestors of gymnosperms. These are tall trees with long, strap-like leaves collected in dense bunches. Cordaites grew on the edges of swamps, preferring them to muddy swamps.

In the southeast of North America, on the Mississippi River, swamp cypress forests rose in the peat bogs flooded by its waters. Trees felled by a storm or rotted over time fell to the ground and, together with ferns and mosses, slowly decomposed with poor air access.

There was silence in the forests. Only occasionally will a huge, clumsy amphibian rustle among the ferns. It crawls slowly under the foliage, hiding from the daylight. Yes, somewhere in the heights a rare insect will fly - a novelty of that period, with wings up to 70 centimeters in span. No birds singing, no grasshoppers chirping.

Before the appearance of ferns and mosses, there were no fertile soils on Earth. There were clays and sands, but they were not yet soil in our modern understanding, because they did not contain humus. In coal forests, the accumulation of plant residues and the formation of a dark layer - humus - begins. Together with clays and sands, it gave rise to fertile soils.

In brown coal deposits there are whole trees, with bark and leaves. A piece of fossil coal under a microscope revealed the anatomical structure of these plants. It turned out to be the same as that of modern conifers. Consequently, brown coal was formed later, when conifers took a dominant position on Earth, pushing aside pteridophytes. This could happen with an increase in land mass and climate change towards greater dryness: from island to continental.

Above the thick layers of coal in our largest coal basins - Kuznetsk, Donetsk, Moscow Region and others - the lights of big cities sparkle, the laughter of children and the songs of youth are heard, trains run, airplanes fly. There is an inexhaustible search by man for a better life... And once upon a time there were marshy shores of small sea bays, covered with the vegetation of the humid tropics. This was learned from a microscopic section of petrified wood, made in the form of a thin section. Petrified trunks from the Donetsk basin turned out to lack the growth rings typical of northern trees.

Such rings form in the wood of modern temperate trees because they grow vigorously in spring and summer, but stop growing in winter. And in the cross section you can immediately distinguish the wide summer layers of wood from the narrow winter ones. The wood of many tropical plants does not have growth rings. This means that in those distant times, in the territory of the modern Donetsk basin, there was even warm and humid weather all year round, as in humid equatorial forests.

In the northern regions of the USSR, in ancient stone layers of the earth, the remains of laurels, magnolias, cypresses, that is, the Mediterranean flora, are found. On Spitsbergen, where only small herbs and shrubs currently grow, remains of plane trees and walnuts are found.

Lush palm trees once grew in the lower reaches of the Volga. Mediterranean vegetation flourished on the shores of the modern Baltic Sea. Tree ferns, laurels, famous mammoth trees, palm trees - everything that we now see in botanical gardens grew under our sky.

Greenland is even more amazing. Under the solid ice, magnolia, oaks, and grapes were found in the ground. In India, on the contrary, the flora of the Carboniferous period was characterized by low growth, coarse dense leaves, and the development of shrubs and grasses. And this is evidence of a colder and drier climate.

“In ancient times, there were great heat waves in the northern regions,” wrote M.V. Lomonosov, “where elephants could be born and reproduce, as well as ordinary plants near the equator, it was possible to stay.”

What explanation does science give for these amazing facts? Once upon a time, all the continents made up a single continent, which then split into parts that moved apart in different directions. The movement of continents caused a shift in the earth's axis. Together with it, the positions of the points of the North and Skin poles lying on it changed, and, consequently, the equator.

If we agree with this theory, then in the Carboniferous period the equator did not pass where it passes now, but further north: through Central Europe and the Caspian Sea. And the entire Donetsk basin was in a strip of humid equatorial forests, which is confirmed by its fossil vegetation. The subtropics went far to the north, and the point of the North Pole then lay somewhere off the eastern coast of America. On the continents of the Southern Hemisphere - Australia, Africa, South America, which were not yet separated at that time, the climate was cold. This explains the absence of tropical vegetation in the Carboniferous terrestrial strata on the continents of the Southern Hemisphere.

It is believed that the Carboniferous forests grew more than two hundred million years ago and that in the next, Permian, period, the dominance of ferns ended. Carboniferous forests died for various reasons. In some places, the sea flooded forests on the sunken parts of the earth's surface. Sometimes they died, captured by swamps.

In many cases, climate change has caused their demise. The sun in their heyday never burned with its rays: they were softened by heavy clouds hanging low over the forest. Now the sky became cloudless and the sun sent burning rays to the plants. For ferns these conditions were unbearable, and they became noticeably smaller, taking refuge only in the shade of the more hardy gymnosperms.

With their death, the Middle Ages began for the forests of the Earth, leaving their traces in the stone book of our planet.

The climate on Earth, in connection with the processes of mountain building, became more diverse. Mountain ranges stood as a wall in the path of moist sea winds and fenced off the interior spaces of the continents, turning them into deserts.

On the territory of the European part of the USSR, a majestic mountain range - the Ural Mountains - rose from the bottom of what was then the Ural Sea. Now we know it as decrepit, dilapidated, but in the days of its youth the Urals were mighty, and eternal snow crowned its peaks. In place of the Donetsk Sea, a mountain range appeared - Donetsk, completely smoothed by time.

Central Europe gradually moved from the equator zone to the zone of subtropical steppes and deserts, and then to the temperate zone. In a drier and colder climate, people from the cold countries of the Southern Hemisphere, where warming has begun, felt great.

In the dry and hot climate of the early Middle Ages, the most ancient coniferous araucaria and interesting gymnosperms - ginkgo - developed. In appearance, this plant appears to be an ordinary broad-leaved tree. But its “leaf” is a wide bipartite fan-shaped needle with a forked arrangement of veins. There were no longer any lepidodendrons, no sigillarias, no cordaites; Only the seed ferns survived.

The climate has changed again: it has become wetter and milder. Along the shores of the tropical seas that covered the southern regions of the USSR and washed the Far East and Turkestan, gymnosperm forests grew luxuriantly, especially the so-called cycads and bennetites. But they did not remain masters of the situation for long, and now only fossil finds testify to them. In Mexico they found a layer 600 meters thick; at one time it was a whole forest of Bennettites. We found their remains in the vicinity of Vladivostok and Turkestan.

Darwin encountered fossilized conifers in the Cordillera at an altitude of more than 2000 meters; eleven of them stood in the form of trees, although petrified, and thirty to forty others had already turned into white lime spar, and their stumps stuck out above the ground. Once upon a time they extended their branches over the very ocean, which at that time approached the foot of the Cordillera. They were nurtured by volcanic soil that rose above sea level. Then the area became the seabed again and the waves rolled over the tops of the flooded trees. The sea dragged sand, gravel, pebbles onto them, and lavas from underwater volcanoes lay on top. Hundreds of millennia passed... The seabed rose again and was exposed. Valleys and ravines cut it apart. An ancient grave was opened, and the hidden monuments of the past appeared on the surface of the earth. The soil that once nourished them, and they themselves turned to stone.

Many conifers have survived to this day, having endured violent upheavals of mountain formations, climate changes and, most importantly, surviving even with the advent of the most advanced flora - angiosperms.

In just half a million years, this group of plants captured the entire globe from the poles to the equator, settled everywhere and gave rise to the highest number of species in the entire long history of plants on Earth.

From a geological point of view, half a million years is a short period. The victory of the angiosperms, compared with the entire history of vegetation over hundreds of millions of years, and perhaps more than a billion, is like a flood that suddenly engulfed our entire planet. Like an explosion of new plant species!

But what ensured such a victory for the angiosperms? Many reasons: amazing flexibility in adapting to different living conditions, different climates, soils, temperatures. The appearance and development simultaneously with angiosperms of pollinating insects: butterflies, flies, bumblebees, bees, beetles. The birth of a perfect flower with a green calyx and a bright corolla, with a delicate aroma, with ovules protected by the ovary.

But the main thing is different. The fact is that angiosperms on land fulfill their cosmic role in nature better than all other green plants. Their crown, branches, leaves are widely spread in the air and receive solar energy and carbon dioxide on several floors. No other group of plants had such capabilities.

Green algae in the World Ocean, which for the first time caught the sun's ray with the help of chlorophyll grains, multicellular algae, mosses and lichens, ferns, gymnosperms, angiosperms - all links of the great green chain on Earth eternally serve a single goal: to catch the sun's ray. But angiosperms improved in this direction better than other plants.

We have turned over only a few pages from the chronicle, but they are also vivid witnesses to the panorama of forests on our planet, forever moving in space and time.

Carboniferous period (Carboniferous)

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According to geochronological scale Carboniferous period, or, as it is more often called - carbon, is the penultimate period of the Paleozoic era, occurring after the Devonian and before the Permian. It began 358 million years ago, lasted about 60 million years and ended 298 million years ago. Carboniferous was notable for the fact that it was during this period that huge accumulations of coal deposits were deposited in the earth's crust, and the outlines of the ancient supergiant continent of Pangea first appeared on the globe.

Main subsections of the Carboniferous period, its geography and climatic features

The Carboniferous period is usually divided into two superdivisions: Pennsylvanian and Mississippian. The Pennsylvanian is in turn divided into the Upper and Middle Carboniferous, the Mississippian equally corresponds to the Lower. The Upper Carboniferous includes the Gzhel and Kasimov stages, the Middle is subdivided into the Moscow and Bashkir, and the Lower Carboniferous consists of three stages - Serpukhovian, Visean and ends it, like the entire Carboniferous as a whole - Tournaisian.

Carboniferous period (Carboniferous)	Super departments	Departments	tiers
	Pennsylvanian	Upper carbon	Gzhelsky
			Kasimovsky
		Medium carbon	Moscow
			Bashkir
	Mississippian	Lower Carboniferous	Serpukhovsky
			Visean
			Tournaisian

Throughout the Carboniferous, the southern continent of Gondwana moved closer and closer to the more northern Laurasia, which ended with their partial reunification by the end of the Carboniferous period. Before the collision, under the influence of tidal forces, Gondwana turned clockwise so that its eastern part, which later provided the basis for the creation of India, Australia and Antarctica, moved south, and its western part, from which present-day Africa and South America later emerged, ended up on north. The result of this turn was the formation of the Tethys Ocean in the eastern hemisphere, and the disappearance of the old Rhea Ocean. Simultaneously with these processes, the smaller continental elements of the Baltic and Siberia converged, until, finally, the ocean between them completely ceased to exist, and these continents collided. All this continental restructuring was accompanied by the emergence of new mountain ranges and violent volcanic activity.

By the beginning of the Carboniferous period, the coastal mountain landscape, which did not allow moist air masses to pass to the territory of the continents, and which caused heat and drought in large parts of the land in the Devonian, due to the advance of the seas, was washed away and collapsed into the abyss of water. As a result, a warm and humid climate, akin to the current tropical one, was established throughout the continents, which contributed to the further development and prosperity of organic life on the planet.

Sedimentation in the Carboniferous period

Sedimentary deposits of the seas in the Carboniferous period were formed from clay, sandstone, limestone, shale and rocks of volcanic activity. Clay, sandstone and small amounts of other rocks accumulated on land. In some areas of land, namely in places where carbon forests grew, the main sedimentary rocks at this stage were coal, after which this period was named.

Intense mountain-building processes, accompanied by active volcanic activity, caused the release of huge masses of volcanic ash into the atmosphere of the planet, which, distributed over land, served as an excellent fertilizer for Carboniferous soils. This created the preconditions for primeval forests, finally breaking away from wet swamps, lagoons and other coastal areas, to move deeper into the continents. Carbon dioxide, actively released from the bowels of the earth during volcanic processes, also contributed to the increasing growth of greenery. And along with the forests, land and living creatures moved deeper into the continents.

Rice. 1 - Animals of the Carboniferous Period

But it’s still worth starting with the ancestors of all living things - the oceanic, sea depths and other bodies of water.

Underwater animals of the Carboniferous period were even more diverse than in the Devonian. Foraminifera of various species became widely developed, and later, by the middle of the period, Schwagerina spread. Basically, they were the main source of limestone accumulation. Among the corals, there was a displacement of the tabulaids by chaetetids, of which almost none remained by the end of the Carboniferous period. Brachiopods have also developed unusually. Among them, the most noticeable are productides and spirepherides. In some places, the seabed was completely covered with sea urchins. Also, large areas of the bottom plains are overgrown with thickets of crinoids. Conodonts are also especially numerous at this time. Cephalopods in the Carboniferous were mainly represented by a group of ammonoids with a simple structure of partitions, which included, for example, goniatites and agoniatites, whose lobed lines and shell sculpture underwent a number of evolutionary improvements, becoming much more complex. But nautiloids did not take root in the Carboniferous. By the end of the period, almost all of them disappeared, only some varieties of nautiluses remained, which have safely survived to this day. All kinds of gastropods and bivalves also received an impetus in their development, and the latter populated not only the depths of the sea, but also moved to freshwater inland rivers and lakes.

During the Carboniferous period, almost all trilobites died out; just a few periods ago, they reigned supreme over the entire territory of the aquatic world and witnessed the emergence of terrestrial life. This happened for two main reasons. The body structure of trilobites was flawed and retarded in development compared to other inhabitants of the depths. The shells could not protect their soft bellies, and over time they never grew organs of attack and defense, which is why they often became prey for sharks and other underwater predators. The second reason was the unusually expanded and multiplied mollusks, which ate the same food as they did. Often, the passing army of mollusks destroyed everything edible in its path, thereby dooming the hapless and helpless trilobites to starvation. Some species of trilobites held on to existence until the last, having learned, like today's armadillos, to curl up into a hard chitinous ball. But by that time, many predatory fish of the Carboniferous period had developed their jaws to such an extent that it was not difficult for them to bite through some chitinous ball.

And on land at that time there was a paradise for insects. And despite the fact that many of their ancient species, which descended from branching varieties of Ordovician trilobites, became extinct in the Upper Carboniferous, this served as a surge in the emergence of an even greater diversity of insects. While various scorpions and crustaceans were breeding in the puddles and swamp slush, their renewed relatives were intensively exploring the airspace. The smallest flying insects were 3 centimeters long, while the wingspan of some Stenodicty and Meganeuron dragonflies reached 1 meter (Fig. 2). It is noteworthy that the body of the ancient meganeura dragonfly consisted of 21 segments, 6 of which were on the head, 3 on the chest, 11 on the abdomen, and the terminal segment was very similar to the awl-shaped tail of distant relatives - trilobites. The insect had many pairs of segmented legs, with the help of which it both walked and swam beautifully. Meganeuras were born in water and for some time led the life of trilobites, until the molting process began, after which the insect was reborn in its new dragonfly-like appearance.

Rice. 2 - Meganeura (insect of the Carboniferous period)

Not only dragonflies, but also the first termites, and Eurypterus gave rise to ants, evolved from extinct ancient Orthoptera. But be that as it may, almost everything insects of the Carboniferous period could reproduce only in water, and therefore were tied to sea coasts, inland rivers, seas, lakes and swampy areas. For insects living near small bodies of water, drought turned into a real disaster.

Meanwhile, the depths of the sea were filled with a host of species of predatory fish and sharks (Fig. 3). Of course, they were still far from the sharks of modern times, but be that as it may, for the seas of those times they were real killing machines. Their reproduction sometimes reached the point where they had nothing to eat, since they had already exterminated all the living creatures in the area. Then they began to hunt each other, which forced them to acquire all sorts of sharp spines for protection, to grow additional rows of teeth for a more effective attack, and some even began to change the structure of their jaws, turning their heads into all kinds of swords, or even into saws. This entire army of predators, as a result of active reproduction, led to overpopulation of the seas, as a result of which predators of the Carboniferous period, like the current locusts, destroyed all mollusks with relatively soft shells, single corals, trilobites and other inhabitants of water basins.

The danger of dying from the jaws of sharks served as another incentive for the relocation of aquatic life to land. Other species of enamel-scaled lobe-finned fish that lived in freshwater bodies also continued to come to land. They were excellent at jumping along the coast, feeding on small insects. And, in the end, life finally spilled out onto the vast expanses of land.

Rice. 3 - Carboniferous Shark

Ancient amphibians could so far only live at the water's edge, since they still laid eggs in reservoirs for reproduction. Their skeletons were not yet completely bone, but this did not prevent some varieties from growing up to 5 meters in size. As a result, the multiplied stegocephals began to produce varieties. Many were similar in structure to newts and salamanders. Legless snake-like species also appeared. Amphibians are different in that their skull, not counting the mouth, had not 4, but 5 holes - 2 for the eyes, 2 for the ears and 1 in the middle of the forehead - for the parietal eye, which later, as unnecessary, turned into the pineal gland and became an appendage of the brain. The backs of amphibians were naked, and soft scales grew on their bellies.

Flora of the Carboniferous Period(Fig. 4) consisted of ferns, mosses and arthroplastes that had already developed significantly at the beginning. Towards the end of the period, the first horsetails began to appear.

Some lycophytes reached a height of up to 40 m with a 2-meter width of the initial trunk. Their wood did not yet contain growth rings; often it was simply an empty trunk, branched from above by a dense crown. Horsetail leaves sometimes reached a meter in length, and plant buds developed at their ends. At that time, this type of propagation was very justified, and the plants developed with enormous intensity. There were extremely many species of club mosses; there were also club-moss-shaped lepidodendrons, the trunk of which was delimited into rhomboid sections and stiglaria, with hexagonal demarcations. The trunk had no branches at all; only sporongia grew on it for reproduction.

The arthropods gave rise to two main varieties - calamites and cuneate. Wedge-leaved plants grew in coastal areas in water, holding onto it with the help of stem branches in the lower part. Their leaves grew directly from the stem, rarely alternating with kidney-shaped spore-containing structures. They first appeared in the Middle Carboniferous, but could not survive the Permian period, during which they all became extinct.

Rice. 4 - Plants of the Carboniferous period

Calamites had a tree-like structure and reached 30 meters in height. Some of them, in the second half of the Carboniferous period, began to grow lateral branches from the stem, and their wood acquired rings. Many coastal or swampy areas were so overgrown with these plants that they turned into an impassable thicket, the flesh up to the crowns clogged with fallen, dead predecessors. Sometimes dozens of them fell into the swampy slurry, settling there to the bottom and becoming increasingly compressed.

Ferns also multiplied abundantly. In general, during the humid and warm season Carboniferous climate Reproduction using spores gave amazing results. The forests grew to such an extent that the dead plants were no longer able to fall to the ground, there was simply no room for this, and they remained sticking out between living plants. Over time, the interior forest began to resemble a giant tree sponge. The bacteria could no longer cope with such an amount of wood, and therefore the slowly compressed and settling wood remained in its original form, turning into coal concentrate over the years. And new plants, meanwhile, grew right on top of their “compressed” ancestors, which led to gigantic accumulations of anthracite.

By the end of the Carboniferous period, with the appearance of the first horsetails, the earth was covered with grass. Ferns gave rise to tree-like forms, which subsequently began to reproduce by seeds. But not so many gymnosperms are known from the Carboniferous; the competition from the clubmoss, pteridophytes and arthropods was too enormous. But their advantage was that they had an extensive root system, much more efficient and extensive than others. Carboniferous plants, as a result of which they could grow at a considerable distance from the reservoir. Subsequently, these plants began to move further and further away from the water, populating ever larger areas of land.

Also during the Carboniferous, the first mushrooms and bryophyte-type plants began to appear.

Minerals of the Carboniferous Period

The main mineral resource of the Carboniferous period is coal. Over 60 million years, so much woody sedimentary rocks have accumulated that the “black gold” will last for many more tens, if not hundreds of years. Also, half of all earthly oil reserves can be attributed to the Carboniferous. Deposits of bauxite (Severo-Onezhsk), copper ores (Dzheskazgan) and lead-zinc deposits (Karatau ridge) were formed in small quantities in certain areas of the earth.