The Quaternary period or Anthropogene is the third period of the era, the last, at the moment, period of the history of the Earth. The Quaternary began 2.588 million years ago and continues today. You can get acquainted with the complete geochronological scale of the history of the Earth. The duration of the Anthropogen is unknown, since its change requires a noticeable change in conditions on the planet.

The Quaternary period is divided into two eras: (2.588 million years ago - 11.7 thousand years ago) and (11.7 thousand years ago - today).

The Quaternary period is the shortest geological period of all the distinguished periods in the history of the Earth. However, this period is incredibly rich in events from the field of relief formation and the development of life. By the way, it was in this period that a person appeared who evolved from higher primates that appeared in.

The first epoch of the Quaternary period (Pleistocene) is the time of glacial glaciations. Often, glaciers occupied vast territories, turning thousands of kilometers into glacial deserts. Ice caps covered vast areas of Europe, Asia and North America. During the Great Ice Age of the Earth, glaciers in some places reached two kilometers in height. Glaciation periods were replaced by relatively warm periods of time when glaciers retreated.

Due to the glaciation of the Earth, the forms of life on the planet also changed. Glaciers pushed animals from inhabited places to new lands. Some animals, such as the mammoth and the woolly rhinoceros, adapted to the new conditions, getting a thick coat and a thick layer of subcutaneous fat. Many scientists believe that it was the difficult conditions of the ice age in the Pleistocene that contributed to the faster evolution of man. At the end of the Pleistocene and the beginning of the Holocene, such animals as mammoths, mastodons, saber-toothed cats, giant sloths, big-horned deer, cave bears, cave lions and others became extinct. Scientists attribute this to climate change. Also, the reduction in the ranges of animals and the complete extinction of some species are associated with the actions of human ancestors, who by the beginning of the Holocene had evolved into Homo sapiens. In particular, it is believed that the Cro-Magnons (the ancestors of man) could exterminate not only some species of animals that were hunted for food and skins, but also all that lived at the same time, but could not endure the competition of a stronger species.

The Holocene, which began 11.7 thousand years ago, is characterized by a relatively stable climate. It is considered a typical interglacial epoch. During this period, many animal species became extinct, but in general, changes in fauna and flora are considered insignificant. It is noted that the climate of the Holocene is becoming warmer with time. It is also associated with human activities. From the middle of the Holocene, the formation of human civilization begins.

Currently, the Cenozoic era continues on Earth. This stage of the development of our planet is relatively short when compared with the previous ones, for example, the Proterozoic or Archean. While it is only 65.5 million years.

The geological processes that took place during the Cenozoic shaped the modern appearance of the oceans and continents. Gradually, the climate changed and, as a result, the flora in one or another part of the planet. The previous era - the Mesozoic - ended with the so-called Cretaceous catastrophe, which led to the extinction of many animal species. The beginning of a new era was marked by the fact that the empty ecological niches began to be filled again. The development of life in the Cenozoic era took place rapidly both on land and in water and in the air. The dominant position was occupied by mammals. Finally, human ancestors appeared. People turned out to be very "promising" creatures: despite repeated climate changes, they not only survived, but also evolved, settling all over the planet. Over time, human activity has become another factor in the transformation of the Earth.

Cenozoic era: periods

Previously, the Cenozoic (“era of new life”) was usually divided into two main periods: Tertiary and Quaternary. Now there is another classification. The very first stage of the Cenozoic is the Paleogene ("ancient formation"). It began about 65.5 million years ago and lasted 42 million years. The Paleogene is divided into three sub-periods (Paleocene, Eocene and Oligocene).

The next stage is the Neogene ("new formation"). This epoch began 23 million years ago, and its duration was approximately 21 million years. The Neogene period is divided into Miocene and Pliocene. It is important to note that the emergence of human ancestors dates back to the end of the Pliocene (although at that time they did not even resemble modern people). Somewhere 2-1.8 million years ago, the Anthropogenic, or Quaternary period began. It continues to this day. Throughout the Anthropogen, human development took place (and is happening). The sub-periods of this stage are the Pleistocene (epoch of glaciation) and Holocene (post-glacial epoch).

Climatic conditions of the Paleogene

The long period of the Paleogene opens the Cenozoic era. The climate of the Paleocene and Eocene was mild. At the equator, the average temperature reached 28 °C. In the North Sea area, the temperature was not much lower (22-26 °C).

On the territory of Svalbard and Greenland, evidence was found that plants characteristic of modern subtropics felt quite comfortable there. Traces of subtropical vegetation have also been found in Antarctica. There were no glaciers or icebergs in the Eocene yet. There were areas on Earth that did not lack moisture, regions with a variable humid climate and arid regions.

During the Oligocene period, it became sharply colder. At the poles, the average temperature dropped to 5°C. The formation of glaciers began, which later formed the Antarctic Ice Sheet.

Paleogene flora

The Cenozoic era is the time of the widespread domination of angiosperms and gymnosperms (conifers). The latter grew only in high latitudes. The equator was dominated by rainforests, which were based on palm trees, ficuses and various representatives of sandalwood. The farther from the sea, the drier the climate became: in the depths of the continents savannahs and woodlands spread.

In the middle latitudes, moisture-loving tropical and temperate plants (tree ferns, breadfruit, sandalwood, banana trees) were common. Closer to high latitudes, the species composition became completely different. These places are characterized by typical subtropical flora: myrtle, chestnut, laurel, cypress, oak, thuja, sequoia, araucaria. Plant life in the Cenozoic era (in particular, in the Paleogene era) flourished even beyond the Arctic Circle: in the Arctic, Northern Europe and America, the predominance of coniferous-broad-leaved deciduous forests was noted. But there were also subtropical plants listed above. The polar night was not an obstacle to their growth and development.

Paleogene fauna

The Cenozoic era provided the fauna with a unique chance. The animal world has changed dramatically: the dinosaurs were replaced by primitive small mammals that live mainly in forests and swamps. There are fewer reptiles and amphibians. Various proboscis animals predominated, including indicotheres (similar to rhinoceroses), tapir and pig-like animals.

As a rule, many of them were adapted to spend part of the time in the water. During the Paleogene period, the ancestors of horses, various rodents, and later predators (creodonts) also appear. Toothless birds nest on the tops of trees, predatory diatryms live in the savannas - birds that cannot fly.

Great variety of insects. As for the marine fauna, the flowering of cephalopods and bivalves, corals begins; primitive crayfish, cetaceans appear. The ocean at this time belongs to bony fish.

Neogene climate

The Cenozoic era continues. The climate in the Neogene era remains relatively warm and rather humid. But the cooling, which began in the Oligocene, makes its own adjustments: the glaciers no longer melt, the humidity drops, and the continental climate intensifies. By the end of the Neogene, the zonality approached modern (the same can be said about the outlines of the oceans and continents, as well as about the topography of the earth's surface). The Pliocene marked the beginning of another cold snap.

Neogene, Cenozoic era: plants

At the equator and in the tropical zones, either savannahs or moist forests still prevail. The temperate and high latitudes could boast of the greatest diversity of flora: deciduous forests, mostly evergreen, were widespread here. As the air drier, new species appeared, from which the modern flora of the Mediterranean gradually developed (olive, plane trees, walnut, boxwood, southern pine and cedar). In the north, evergreens no longer survived. On the other hand, coniferous-deciduous forests showed a wealth of species - from sequoia to chestnut. At the end of the Neogene, such landscape forms as taiga, tundra and forest-steppe appeared. Again, this was due to the cold. North America and Northern Eurasia became taiga regions. In temperate latitudes with an arid climate, steppes were formed. Where there used to be savannahs, semi-deserts and deserts arose.

Neogene fauna

It would seem that the Cenozoic era is not so long (in comparison with others): flora and fauna, however, have changed a lot since the beginning of the Paleogene. Placentals became the dominant mammals. At first, the anchitherian and then the hipparion fauna developed. Both are named after characteristic representatives. Anchiterium is the ancestor of the horse, a small animal with three fingers on each limb. Hipparion is, in fact, a horse, but still three-toed. There is no need to think that only relatives of horses and simply ungulates (deer, giraffes, camels, pigs) belonged to the indicated faunas. In fact, among their representatives were predators (hyenas, lions), and rodents, and even ostriches: life in the Cenozoic era was fantastically diverse.

The spread of these animals was facilitated by an increase in the area of ​​savannahs and steppes.

At the end of the Neogene, human ancestors appeared in the forests.

Anthropogenic climate

This period is characterized by alternation of glaciations and warmings. When the glaciers advanced, their lower boundaries reached 40 degrees north latitude. The largest glaciers of that time were concentrated in Scandinavia, the Alps, North America, Eastern Siberia, the Subpolar and Northern Urals.

In parallel with the glaciations, the sea attacked the land, although not as powerful as in the Paleogene. Interglacial periods were characterized by a mild climate and regression (drying of the seas). Now the next interglacial period is underway, which should end no later than in 1000 years. After it, another glaciation will occur, which will last about 20 thousand years. But it is not known whether this will actually happen, since human intervention in natural processes has provoked climate warming. It is time to think whether the Cenozoic era will end in a global ecological catastrophe?

Flora and fauna of Anthropogen

The onset of glaciers forced heat-loving plants to shift south. True, mountain ranges interfered with this. As a result, many species have not survived to this day. During the glaciations, there were three main types of landscapes: taiga, tundra and forest-steppe with their characteristic plants. Tropical and subtropical belts were greatly narrowed and shifted, but still remained. In the interglacial periods, broad-leaved forests dominated the Earth.

As for the fauna, the supremacy still belonged (and belongs) to mammals. Massive, woolly animals (mammoths, woolly rhinos, megaloceros) have become the hallmark of the ice ages. Along with them there were bears, wolves, deer, lynxes. All animals as a result of cooling and warming were forced to migrate. The primitive and the unadapted were dying out.

Primates also continued their development. The improvement of the hunting skills of human ancestors can explain the extinction of a number of game animals: giant sloths, horses of North America, mammoths.

Results

It is not known when the Cenozoic era, the periods of which we examined above, will end. Sixty-five million years by the standards of the universe is quite a bit. However, during this time, continents, oceans and mountain ranges managed to form. Many species of plants and animals have died out or evolved under the pressure of circumstances. Mammals have taken the place of dinosaurs. And the most promising of the mammals turned out to be man, and the last period of the Cenozoic - the anthropogen - is associated mainly with the activities of people. It is possible that it depends on us how and when the Cenozoic era will end - the most dynamic and shortest of the earth's eras.

The Quaternary period of the Cenozoic era was marked by a large-scale glaciation, which had a huge impact on the development of life on the planet. As the glaciers advanced, the climatic barrier of life slowly moved south, the wild vegetation of the Cenozoic also retreated south. In the interglacial epochs, it again returned to its original territories. True, in some regions of the world, the return of vegetation was often blocked by mountain ranges, which predetermined the extinction of many plants in the temperate zone. Their fate was shared by some groups of animals, directly or indirectly dependent on certain types of vegetation.
Many representatives of the animal world managed to adapt to the intensified cold weather, acquiring thick hair. The Pleistocene era is characterized by a wide distribution of saber-toothed cats, marsupials and cave lions. In the Pleistocene, the first people appeared, and many large mammals, on the contrary, began to die out. Cooling alternated with warming. During the ice age, three zones of vegetation were clearly distinguished on the planet: tundra, steppe and taiga. They were located south of the advancing glaciers, in an area 200-320 km wide. Thus, repeated glaciations significantly devastated the flora of the planet, and the return of heat-loving plants from south to north was hampered by mountain ranges that acted as barriers to the settlement of vegetation.
Nevertheless, in the warmest interglacial epochs of the Quaternary period, broad-leaved forests were widespread, dominated by oak, beech, linden, maple, ash, hornbeam, alder, walnut and hawthorn. During a large-scale glaciation, water vapor condensed in the form of snow, but the melting of ice and snow annually produced less water than snow fell. The gradual accumulation of ice reserves on land contributed to lowering the level of the World Ocean. Therefore, in the Quaternary period, special land bridges arose between continental Europe and the British Isles, Asia and North America, the Amur region and Sakhalin, as well as between the Indochina peninsula and the islands of the Sunda archipelago.
These land bridges carried out the exchange of animals and plants. At the same time, it was precisely the absence of a connecting link between Asia and Australia that preserved the life of cloacal and marsupials, which, even in the Tertiary period, were completely replaced by placental mammals on other continents of the planet. In the Quaternary period, various groups of mammals and, in particular, elephants met. The largest of them lived in forests and had a shoulder height of over 4 m. In the Siberian tundra, the cold-loving mammoth Mammuthus primigenius, covered with thick and long reddish hair, occupied a dominant position. During one of the ice ages, mammoths probably crossed the ice of the Bering Strait and settled throughout North America. Skeletons of heavy-weight mastodons are often found today in this region of the world.
Prominent representatives of the fauna of that time are large woolly rhinos, which lived in the tundra next to mammoths during the glaciation era. There was also a resettlement of horses, whose homeland is North America. Moving through Asia and Europe, they gradually settled around the world. It is noteworthy that in North America itself, horses died out by the end of the Pleistocene and returned there only with the European conquerors. It is a pity that we were never able to see them, because these animals had a delightful appearance. Today, many fans of the world of fauna like to put pictures of animals in photo frames and hang them on their walls. But it is better, of course, to insert photos of loved ones there.
Numerous subspecies of the wild horse inhabited the savannas of the European continent as early as the beginning of the Quaternary. Among the ruminant artiodactyls, one can distinguish a huge large-mouthed deer, the distance between the horns of which reached 3 m. Musk oxen, primitive bison and aurochs, the ancestors of modern domestic bulls, bred in large numbers. In the Quaternary period, our planet was also inhabited by numerous predators, among them we can note the huge cave bears Ursus spelaeus, the saber-toothed tigers Machairodus, whose long fangs resembled crooked Turkish scimitars, and the cave lions Pamhera spelaea. The well-known hyenas, wolves, foxes, raccoons and wolverines already lived in the glacial stage.

The Holocene epoch of the Quaternary period is the time of the formation of the modern appearance of the fauna and flora of our planet. The diversity of living organisms today is noticeably less than in past geological epochs. This may have contributed to the intense human impact on the environment. The appearance of the first great apes as early as the Tertiary period ensured their further evolution in the Quaternary period of the Cenozoic. It became possible the appearance of the ancient ancestors of modern man - Driopithecus and Australopithecus. The next stage in the evolutionary ladder is the emergence of a skilled man, the first representative of the genus Homo, and, finally, the species to which the people living now belong, Homo sapiens. From that moment, a completely new life began on the planet.
In connection with the appearance of modern man and the development of human civilization during the Quaternary period, it was proposed to call this stage of the Cenozoic era the anthropogen. During the Holocene era, human civilization spread throughout the world. It has gradually become the most important global factor that has changed the biosphere of our planet. In particular, the emergence of agriculture has destroyed a large number of wild plant species in order to clear crop areas and pastures. In many cases, the activities of people were ill-conceived and destructive to their environment.
Thus, the Quaternary period of the Cenozoic passed already with the participation and significant influence of man on the world around him. As the ice melted, the human civilization settled on the territories freed from under the glaciers. During this period, mastodons, mammoths, saber-toothed tigers and big-horned deer gradually became extinct. A significant role in this process was again played by ancient people who were actively engaged in hunting. They exterminated the mammoth and woolly rhinoceros in Eurasia, as well as mastodons, horses and sea cows in America. Plowing land, widespread hunting, burning forests for pastures and trampling grass stands by domestic animals have reduced the habitats of many representatives of the steppe fauna. Human activities contributed to the expansion of desert areas and the emergence of shifting sands.
The separation and movement of individual continents, as well as the establishment of climatic zonality, led to the isolation of representatives of the biosphere by region. The development of life in the Cenozoic provided the biological diversity on Earth that we can observe today. The result of the long evolution of life on our planet was the appearance of Homo sapiens at the end of the Quaternary period of the Cenozoic. With the end of prehistoric times, man began to create his own history. If about 4 thousand years ago, about 50 million people lived in the world, then already in the first half of the 19th century, the number of people on the planet exceeded one billion. It is human activity that largely predetermined the species composition of the biosphere that exists at the present time. Man also influenced the modern geographical distribution of living organisms on Earth.

The Cenozoic era is the last known to date. This is a new period of life on Earth, which began 67 million years ago and continues to this day.

In the Cenozoic, the transgressions of the sea ceased, the water level rose and stabilized. Modern mountain systems and relief were formed. Animals and plants acquired modern features and spread everywhere on all continents.

The Cenozoic era is divided into the following periods:

• Paleogene;
• Neogene;
• anthropogenic.

Geological changes

At the beginning of the Paleogene period, Cenozoic folding began, that is, the formation of new mountain systems, landscapes, and reliefs. Tectonic processes took place intensively within the Pacific Ocean and the Mediterranean Sea.

Mountain systems of Cenozoic folding:

1. Andes (in South America);
2. Alps (Europe);
3. Caucasus mountains;
4. Carpathians;
5. Median Ridge (Asia);
6. Partial Himalayas;
7. Mountains of the Cordillera.

As a result of global movements of vertical and horizontal lithospheric plates, they have acquired a form corresponding to the current continents and oceans.

The climate of the Cenozoic era

Weather conditions were favorable, warm climate with periodic rains contributed to the development of life on Earth. In comparison with modern average annual indicators, the temperature of those times was 9 degrees higher. In a hot climate, crocodiles, lizards, turtles adapted to life, which were protected from the scorching sun by developed outer covers.

At the end of the Paleogene period, a gradual decrease in temperature was observed, due to a decrease in the concentration of carbon dioxide in the atmospheric air, an increase in the land area due to a drop in sea level. This led to glaciation in Antarctica, starting from the mountain peaks, gradually the entire territory was covered with ice.

Animal world of the Cenozoic era

At the beginning of the era, cloacal, marsupials and the first placental mammals were widespread. They could easily adapt to changes in the external environment and quickly occupied both the water and air environment.

Bony fish settled in the seas and rivers, birds expanded their habitat. New species of foraminifera, mollusks, and echinoderms have formed.

The development of life in the Cenozoic era was not a monotonous process, temperature fluctuations, periods of severe frosts led to the extinction of many species. For example, mammoths, who lived during the glaciation period, could not survive to our times.

Paleogene

In the Cenozoic era, insects made a significant leap in evolution. While developing new areas, they experienced a number of adaptive changes:

• Received a variety of colors, sizes and body shapes;
• received modified limbs;
• species with complete and incomplete metamorphosis appeared.

Huge mammals lived on land. For example, a hornless rhinoceros is an indricotherium. They reached a height of about 5m, and a length of 8m. These are herbivores with massive three-toed limbs, a long neck and a small head - the largest of all mammals that have ever lived on land.

At the beginning of the Cenozoic era, insectivorous animals split into two groups and evolved in two different directions. One group began to lead a predatory lifestyle and became the ancestor of modern predators. The other part fed on plants and gave rise to ungulates.

Life in the Cenozoic in South America and Australia had its own characteristics. These continents were the first to separate from the Gondwana continent, so the evolution here was different. For a long time, the mainland was inhabited by primitive mammals: marsupials and monotremes.

Neogene

In the Neogene period, the first anthropoid apes appeared. After a cold snap and a decrease in forests, some died out, and some adapted to life in an open area. Soon primates evolved to primitive people. This is how it started Anthropogenic period.

The development of the human race was rapid. People begin to use tools to get food, create primitive weapons to protect themselves from predators, build huts, grow plants, tame animals.

The Neogene period of the Cenozoic was favorable for the development of oceanic animals. Cephalopod mollusks - cuttlefish, octopuses, which have survived to our times, began to multiply especially quickly. Remains of oysters and scallops were found among bivalves. Everywhere there were small crustaceans and echinoderms, sea urchins.

The flora of the Cenozoic era

In the Cenozoic, the dominant place among plants was occupied by angiosperms, the number of species of which increased significantly in the Paleogene and Neogene periods. The spread of angiosperms was of great importance in the evolution of mammals. Primates might not appear at all, since flowering plants serve as the main food for them: fruits, berries.

Conifers developed, but their numbers decreased significantly. The hot climate contributed to the spread of plants in the northern regions. Even beyond the Arctic Circle there were plants from the Magnolia and Beech families.

On the territory of Europe and Asia, camphor cinnamon, figs, plane trees and other plants grew. In the middle of the era, the climate changes, colds come, displacing plants to the south. The center of Europe with a warm and humid environment has become a great place for deciduous forests. Representatives of plants from the Beech (chestnuts, oaks) and Birch (hornbeam, alder, hazel) families grew here. Coniferous forests with pines and yews grew closer to the north.

After the establishment of stable climatic zones, with lower temperatures and periodically changing seasons, the flora has undergone significant changes. Evergreen tropical plants have been replaced by species with falling leaves. In a separate group among the monocots, the Cereal family stood out.

Huge territories were occupied by steppe and forest-steppe zones, the number of forests was sharply reduced, and herbaceous plants mainly developed.

Cenozoic era (Cenozoic)

Page 1 of 11

Cenozoic era represents the current era, which began 66 million years ago, going immediately after the Mesozoic. Specifically, it originates on the border of the Cretaceous and Paleogene, when the second largest catastrophic extinction of species occurred on Earth. This era is significant for the development of mammals that replaced dinosaurs and other reptiles, which almost completely died out at the turn of these eras. In the process of development of mammals, a genus of primates stood out, from which humans later arose. If we translate the concept Cenozoic” from Greek, it will look like “New Life”.

Periods of the Cenozoic era, paleography and climate

Main periods of the Cenozoic era- Paleogene, consisting of the Paleocene (66 - 56 million years ago), Eocene (56 - 34 million years ago) and Oligocene (40 - 23 million years ago), Neogene, the sections of which are Miocene ( 23 - 5 million years ago) and the Pliocene (5 - 2.5 million years ago) and the current Quaternary, dividing into the Pleistocene (2.5 million years ago - about 12 thousand years ago .) and the Holocene, originating about 12 thousand years ago. n. and lasting to this day.

During the Cenozoic era, the geographical outlines of the continents acquired the form that exists today. The North American continent moved further and further away from the remaining Laurasian, and now the Eurasian part of the global northern continent, and the South American segment moved further and further away from the African segment of southern Gondwana. Australia and Antarctica retreated more and more to the south, while the Indian segment was more and more “squeezed out” to the north, until, finally, it joined the South Asian part of the future Eurasia, causing the rise of the Caucasian mainland, and also largely contributing to the rise from the water and the rest of the current part of the European continent.

The climate of the Cenozoic era constantly harsh. The cooling was not absolutely sharp, but still not all groups of animal and plant species had time to get used to it. It was during the Cenozoic that the upper and southern ice caps were formed in the region of the poles, and the climatic map of the earth acquired the zonality that we have today. It is a pronounced equatorial belt along the earth's equator, and further in order of distance to the poles - subequatorial, tropical, subtropical, temperate, and beyond the polar circles, respectively, the arctic and antarctic climatic zones.

Let's take a closer look at the periods of the Cenozoic era.

Paleogene

Throughout almost all Paleogene period In the Cenozoic era, the climate was warm and humid, although a constant trend towards cooling could be traced throughout its length. The average temperature in the North Sea area was kept within 22-26°C. But by the end of the Paleogene, it began to get colder and sharper, and at the turn of the Neogene, the northern and southern ice caps were already formed. And if in the case of the northern sea these were separate areas of alternately formed and melting wandering ice, then in the case of Antarctica, a persistent ice sheet began to form here, which still exists today. The average annual temperature in the region of the current polar circles has dropped to 5°C.

But until the first frosts hit the poles, renewed life, both in the sea and ocean depths and on the continents, flourished. Due to the extinction of dinosaurs, mammals completely populated all continental spaces. During the first two Paleogene divisions, mammals diverged and evolved into many different forms. Many different proboscis animals, indicothere (rhinoceros), tapir and pig-like animals arose. Most of them were chained to some kind of water bodies, but many species of rodents also appeared, which also felt excellent in the depths of the continents. Some of them gave rise to the first ancestors of horses and other one and artiodactyls. The first predators (creodonts) began to appear. New species of birds arose, and vast areas of the savannas were inhabited by diatryms - a variety of flightless bird varieties.

Insects multiplied unusually. In the seas, cephalopods and bivalve molluscs multiplied everywhere. Corals grew very strongly, new varieties of crustaceans appeared, but bony fish received the greatest flourishing.

The most widespread in the Paleogene were such plants of the Cenozoic era, like tree-like ferns, all kinds of sandalwood, banana and breadfruit trees. Closer to the equator, chestnut, laurel, oak, sequoia, araucaria, cypress, and myrtle trees grew. In the first period of the Cenozoic, dense vegetation was also widespread far beyond the polar circles. These were mostly mixed forests, but it was precisely coniferous and deciduous broad-leaved plants that prevailed here, the prosperity of which was absolutely no obstacle to the polar nights.

Neogene

At the initial stage Neogene the climate was still comparatively warm, but a slow cooling trend still persisted. The ice heaps of the northern seas began to melt more and more slowly, until the upper northern shield also began to form. The climate, due to cooling, began to acquire an increasingly pronounced continental color. It was during this period of the Cenozoic era that the continents became most similar to modern ones. South America merged with North America, and just at that time, climatic zoning acquired similar features to modern ones. By the end of the Neogene in the Pliocene, the second wave of sharp cooling hit the globe.

Despite the fact that the Neogene was two times shorter than the Paleogene, it was he who was marked by explosive evolution among mammals. It was placental varieties that dominated everywhere. The main mass of mammals was divided into anchitheria, the ancestors of horse-like and hipparion, also horse-like and three-toed, but gave rise to hyenas, lions and other modern predators. All kinds of rodents were diverse at that time of the Cenozoic era, the first distinct ostrich-like ones began to appear. Due to the cooling and the fact that the climate began to acquire an increasingly continental color, areas of ancient steppes, savannahs and light forests expanded, where the ancestors of modern bison, giraffe-like, deer-like, pigs and other mammals grazed in large numbers, which were constantly hunted by the ancient Cenozoic predators. It was at the end of the Neogene that the first ancestors of humanoid primates began to appear in the forests.

Despite the winters of the polar latitudes, tropical vegetation was still rampant in the equatorial belt of the earth. Broad-leaved woody plants were the most diverse. Consisting of them, as a rule, evergreen forests interspersed and bordered on savannahs and shrubs of other woodlands, subsequently it was they who gave diversity to modern Mediterranean flora, namely olive, plane trees, walnuts, boxwood, southern pine and cedar.

The northern forests were also varied. There were no evergreens here, but in the majority chestnut, sequoia and other coniferous-broad-leaved and deciduous trees grew and took root. Later, in connection with the second sharp cooling, vast areas of tundra and forest-steppes formed in the north. The tundras have filled all the zones with the current temperate climate, and the places where until recently tropical forests have grown luxuriantly have turned into deserts and semi-deserts.

Anthropogen (h quaternary period)

AT Anthropogenic period unexpected warmings alternated with equally sharp cold snaps. The boundaries of the glacial zone of the Anthropogen sometimes reached 40° northern latitudes. Under the northern ice cap were North America, Europe up to the Alps, the Scandinavian Peninsula, the Northern Urals, Eastern Siberia. Also, in connection with glaciation and the melting of ice caps, there was either a decline or a re-advance of the sea to land. The periods between glaciations were accompanied by marine regression and a mild climate. At the moment, one of these intervals is taking place, which should be replaced no later than in the next 1000 years by the next stage of icing. It will last approximately 20 thousand years, until it is again replaced by another period of warming. Here it is worth noting that the alternation of intervals can occur much faster, or it can be completely disturbed due to human intervention in earthly natural processes. It is likely that the Cenozoic era could be ended by a global ecological catastrophe similar to the one that caused the death of many species in the Permian and Cretaceous periods.

Animals of the Cenozoic Era during the Anthropogen period, together with vegetation, they were pushed to the south by alternately advancing ice from the north. The main role still belonged to mammals, which showed truly miracles of adaptability. With the onset of cold weather, massive woolly animals appeared, such as mammoths, megaloceros, rhinos, etc. All kinds of bears, wolves, deer, lynxes also bred strongly. Due to alternating waves of cooling and warming, animals were forced to constantly migrate. A huge number of species died out, and did not have time to adapt to the onset of cooling.

Against the background of these processes of the Cenozoic era, humanoid primates also developed. They increasingly improved their skills in the possession of all kinds of useful objects and tools. At some point, they began to use these tools for hunting purposes, that is, for the first time, tools of labor acquired the status of weapons. And since then, a real threat of extermination has hung over various species of animals. And many animals, such as mammoths, giant sloths, North American horses, which were considered by primitive people to be commercial, were completely destroyed.

In the zone of alternating glaciations, the tundra and taiga regions alternated with forest-steppe, and tropical and subtropical forests were strongly pushed to the south, but despite this, most plant species survived and adapted to modern conditions. The dominant forests between periods of icing were broad-leaved and coniferous.

AT present day of the Cenozoic era Man reigns everywhere on the planet. He randomly interferes in all sorts of earthly and natural processes. Over the past century, a huge amount of substances have been released into the earth's atmosphere, contributing to the formation of the greenhouse effect and, as a result, faster warming. It is worth noting that the more rapid melting of ice and the rise in the level of the world ocean contributes to the disruption of the general picture of the climatic development of the earth. Due to future changes, undercurrents may be disrupted, and, as a result, the general planetary intra-atmospheric heat exchange, which may lead to even more massive icing of the planet following the warming that has begun at the moment. It is becoming more and more clear that what will be the duration of Cenozoic era, and how it will eventually end, will now depend not on natural and other natural forces, but on the depth and unceremoniousness of human intervention in global natural processes.

More details and details periods of the Cenozoic era will be considered in the following lectures.