Modern era. Geological periods in chronological order. Geological history of the Earth
At first there was nothing. In the vast outer space, there was only a giant cloud of dust and gases. It can be assumed that from time to time through this substance at great speed rushed spaceships with representatives of the universal mind. The humanoids boredly looked out of the windows and did not even remotely guess that in a few billion years intelligence and life would arise in these places.
The gas and dust cloud eventually transformed into the solar system. And after the luminary appeared, the planets appeared. One of them was our native Earth. It happened 4.5 billion years ago. It is from those distant times that the age of the blue planet is counted, thanks to which we exist in this world.
Stages of the Earth's development
The entire history of the Earth is divided into two huge time periods. The first stage is characterized by the absence of complex living organisms. There were only single-celled bacteria that settled on our planet about 3.5 billion years ago. The second stage began about 540 million years ago. This is the time when living multicellular organisms settled on the Earth. This refers to both plants and animals. Moreover, both seas and land became their habitat. The second period continues to this day, and its crown is man.
Such huge time steps are called eons. Each eon has its own eonoteme. The latter represents a certain stage in the geological development of the planet, which is fundamentally different from other stages in the lithosphere, hydrosphere, atmosphere, and biosphere. That is, each eonoteme is strictly specific and not similar to others.
There are 4 aeons in total. Each of them, in turn, is divided into eras of the Earth, and those are divided into periods. This shows that there is a rigid gradation of large time intervals, and the geological development of the planet is taken as the basis.
catarchean
The most ancient eon is called Katarchaeus. It began 4.6 billion years ago and ended 4 billion years ago. Thus, its duration was 600 million years. Time is very ancient, so it was not divided into eras or periods. At the time of the Katarchean, there was neither the earth's crust nor the core. The planet was a cold cosmic body. The temperature in its bowels corresponded to the melting point of the substance. From above, the surface was covered with regolith, like the lunar surface in our time. The relief was almost flat due to constant powerful earthquakes. Naturally, there was no atmosphere and oxygen.
archaeus
The second aeon is called Archaea. It began 4 billion years ago and ended 2.5 billion years ago. Thus, it lasted 1.5 billion years. It is divided into 4 eras: Eoarchean, Paleoarchean, Mesoarchean and Neoarchean.
Eoarchean(4-3.6 billion years) lasted 400 million years. This is the period of formation of the earth's crust. A huge number of meteorites fell on the planet. This is the so-called Late Heavy Bombardment. It was at that time that the formation of the hydrosphere began. Water appeared on Earth. In large quantities, comets could bring it. But the oceans were still far away. There were separate reservoirs, and the temperature in them reached 90 ° Celsius. The atmosphere was characterized by a high content of carbon dioxide and a low content of nitrogen. There was no oxygen. At the end of the era, the first supercontinent of Vaalbar began to form.
paleoarchaean(3.6-3.2 billion years) lasted 400 million years. In this era, the formation of the solid core of the Earth was completed. There was a strong magnetic field. His tension was half the current. Consequently, the surface of the planet received protection from the solar wind. This period also includes primitive life forms in the form of bacteria. Their remains, which are 3.46 billion years old, have been found in Australia. Accordingly, the oxygen content in the atmosphere began to increase, due to the activity of living organisms. The formation of Vaalbar continued.
Mesoarchean(3.2-2.8 billion years) lasted 400 million years. Most notable was the existence of cyanobacteria. They are capable of photosynthesis and release oxygen. The formation of a supercontinent has been completed. By the end of the era, it had split. There was also a fall huge asteroid. A crater from it still exists on the territory of Greenland.
neoarchean(2.8-2.5 billion years) lasted 300 million years. This is the time of formation of the real earth's crust - tectogenesis. Bacteria continued to grow. Traces of their life are found in stromatolites, whose age is estimated at 2.7 billion years. These lime deposits were formed by huge colonies of bacteria. They were found in Australia and South Africa. Photosynthesis continued to improve.
With the end of the Archean, the eras of the Earth were continued in the Proterozoic eon. This is a period of 2.5 billion years - 540 million years ago. It is the longest of all eons on the planet.
Proterozoic
The Proterozoic is divided into 3 eras. The first is called Paleoproterozoic(2.5-1.6 billion years). It lasted 900 million years. This huge time interval is divided into 4 periods: siderium (2.5-2.3 billion years), riasium (2.3-2.05 billion years), orosirium (2.05-1.8 billion years) , statery (1.8-1.6 billion years).
siderius remarkable in the first place oxygen catastrophe. It happened 2.4 billion years ago. It is characterized by a radical change in the Earth's atmosphere. It contained a large amount of free oxygen. Prior to this, the atmosphere was dominated by carbon dioxide, hydrogen sulfide, methane and ammonia. But as a result of photosynthesis and the extinction of volcanic activity at the bottom of the oceans, oxygen filled the entire atmosphere.
Oxygen photosynthesis is characteristic of cyanobacteria, which bred on Earth 2.7 billion years ago. Prior to this, archaebacteria dominated. They do not produce oxygen during photosynthesis. In addition, at first oxygen was spent on the oxidation of rocks. IN large quantities it accumulated only in biocenoses or bacterial mats.
In the end, the moment came when the surface of the planet was oxidized. And the cyanobacteria continued to release oxygen. And it began to accumulate in the atmosphere. The process has accelerated due to the fact that the oceans also stopped absorbing this gas.
As a result, anaerobic organisms died, and they were replaced by aerobic ones, that is, those in which energy synthesis was carried out through free molecular oxygen. The planet was enveloped in the ozone layer and the greenhouse effect decreased. Accordingly, the boundaries of the biosphere expanded, and sedimentary and metamorphic rocks turned out to be completely oxidized.
All these metamorphoses led to Huron glaciation, which lasted 300 million years. It began in the siderium, and ended at the end of the riasian 2 billion years ago. The next Orosirium period notable for intensive mountain building processes. At this time, 2 huge asteroids fell on the planet. The crater from one is called Vredefort and is located in South Africa. Its diameter reaches 300 km. Second crater Sudbury is located in Canada. Its diameter is 250 km.
Last statheric period notable for the formation of the supercontinent Columbia. It included almost all the continental blocks of the planet. There was a supercontinent 1.8-1.5 billion years ago. At the same time, cells were formed that contained nuclei. That is eukaryotic cells. This was a very important stage in evolution.
The second era of the Proterozoic is called mesoproterozoic(1.6-1 billion years). Its duration was 600 million years. It is divided into 3 periods: potassium (1.6-1.4 billion years), exatium (1.4-1.2 billion years), stenium (1.2-1 billion years).
At the time of the kalimium, the supercontinent Columbia collapsed. And during the time of exatia, red multicellular algae appeared. This is indicated by a fossil find on the Canadian island of Somerset. Its age is 1.2 billion years. A new supercontinent, Rodinia, formed in the walls. It arose 1.1 billion years ago, and broke up 750 million years ago. Thus, by the end of the Mesoproterozoic, there was 1 supercontinent and 1 ocean on Earth, which was called Mirovia.
The last era of the Proterozoic is called neoproterozoic(1 billion-540 million years). It includes 3 periods: Tonian (1 billion-850 million years), Cryogeny (850-635 million years), Ediacaran (635-540 million years).
During the time of Toni, the disintegration of the supercontinent Rodinia began. This process ended in cryogeny, and the Pannotia supercontinent began to form from 8 separate pieces of land formed. Cryogeny is also characterized by complete glaciation of the planet (Snowball Earth). The ice reached the equator, and after they receded, the process of evolution of multicellular organisms sharply accelerated. The last period of the Neoproterozoic Ediacaran is notable for the appearance of soft-bodied creatures. These multicellular animals are called vendobionts. They were branching tubular structures. This ecosystem is considered the oldest.
Life on Earth originated in the ocean
Phanerozoic
Approximately 540 million years ago, the time of the 4th and last eon, the Phanerozoic, began. There are 3 very important eras of the Earth here. The first is called Paleozoic(540-252 million years). It lasted 288 million years. It is divided into 6 periods: Cambrian (540-480 million years), Ordovician (485-443 million years), Silurian (443-419 million years), Devonian (419-350 million years), Carboniferous (359-299 Ma) and Permian (299-252 Ma).
Cambrian considered the lifetime of trilobites. These are marine animals that look like crustaceans. Together with them, jellyfish, sponges and worms lived in the seas. This abundance of living beings is called Cambrian explosion. That is, there was nothing like this before, and suddenly it suddenly appeared. Most likely, it was in the Cambrian that mineral skeletons began to emerge. Previously, the living world had soft bodies. They, of course, did not survive. Therefore, complex multicellular organisms of more ancient eras cannot be detected.
The Paleozoic is notable for the rapid spread of organisms with hard skeletons. From vertebrates, fish, reptiles and amphibians appeared. IN flora at first, algae predominated. During Silurian plants began to colonize the land. At first Devonian swampy shores are overgrown with primitive representatives of the flora. These were psilophytes and pteridophytes. Plants reproduced by spores carried by the wind. Plant shoots developed on tuberous or creeping rhizomes.
Plants began to develop land in the Silurian period
There were scorpions, spiders. The real giant was the Meganevra dragonfly. Its wingspan reached 75 cm. Acanthodes are considered the oldest bony fish. They lived during the Silurian period. Their bodies were covered with dense diamond-shaped scales. IN carbon, which is also called the Carboniferous period, the most diverse vegetation flourished on the shores of the lagoons and in countless swamps. It was its remains that served as the basis for the formation of coal.
This time is also characterized by the beginning of the formation of the supercontinent Pangea. It was fully formed in the Permian period. And it broke up 200 million years ago into 2 continents. These are the northern continent of Laurasia and the southern continent of Gondwana. Subsequently, Laurasia split, and Eurasia and North America were formed. And South America, Africa, Australia and Antarctica arose from Gondwana.
On Permian there were frequent climate changes. Dry times gave way to wet ones. At this time, lush vegetation appeared on the banks. Typical plants were cordaites, calamites, tree and seed ferns. Mesosaurus lizards appeared in the water. Their length reached 70 cm. But by the end of the Permian period, early reptiles died out and gave way to more developed vertebrates. Thus, in the Paleozoic, life reliably and densely settled on the blue planet.
Of particular interest to scientists are the following eras of the Earth. 252 million years ago mesozoic. It lasted 186 million years and ended 66 million years ago. It consisted of 3 periods: Triassic (252-201 million years), Jurassic (201-145 million years), Cretaceous (145-66 million years).
The border between the Permian and the Triassic period is characterized by the mass extinction of animals. 96% of marine species and 70% of terrestrial vertebrates died. A very strong blow was dealt to the biosphere, and it took a very long time to recover. And it all ended with the appearance of dinosaurs, pterosaurs and ichthyosaurs. These sea and land animals were of enormous size.
But the main tectonic event of those years - the collapse of Pangea. A single supercontinent, as already mentioned, was divided into 2 continents, and then broke up into those continents that we know now. The Indian subcontinent also broke away. Subsequently, it connected with the Asian plate, but the collision was so violent that the Himalayas were created.
Such nature was in the early Cretaceous period
The Mesozoic is notable for being considered the warmest period of the Phanerozoic eon.. This is the time of global warming. It began in the Triassic and ended at the end of the Cretaceous. For 180 million years, even in the Arctic there were no stable pack glaciers. Heat spread evenly throughout the planet. At the equator, the average annual temperature corresponded to 25-30 ° Celsius. The polar regions were characterized by a moderately cool climate. In the first half of the Mesozoic, the climate was dry, while the second half was characterized by humid. It was at this time that the equatorial climatic zone was formed.
In the animal world, mammals arose from a subclass of reptiles. It was related to improvement. nervous system and the brain. The limbs moved from the sides under the body, the reproductive organs became more perfect. They ensured the development of the embryo in the mother's body, followed by feeding it with milk. A woolen cover appeared, blood circulation and metabolism improved. The first mammals appeared in the Triassic, but they could not compete with dinosaurs. Therefore, for more than 100 million years, they occupied a dominant position in the ecosystem.
The last era is Cenozoic(beginning 66 million years ago). This is the current geological period. That is, we all live in the Cenozoic. It is divided into 3 periods: the Paleogene (66-23 million years), the Neogene (23-2.6 million years) and the modern anthropogen or Quaternary period, which began 2.6 million years ago.
There are 2 major events in the Cenozoic. The mass extinction of dinosaurs 65 million years ago and the general cooling on the planet. The death of animals is associated with the fall of a huge asteroid with a high content of iridium. The diameter of the cosmic body reached 10 km. This resulted in the formation of a crater. Chicxulub with a diameter of 180 km. It is located on the Yucatan Peninsula in Central America.
Earth's surface 65 million years ago
There was an explosion after the fall. great strength. Dust rose into the atmosphere and covered the planet from the sun's rays. The average temperature dropped by 15°. Dust hung in the air for a whole year, which led to a sharp cooling. And since the Earth was inhabited by large heat-loving animals, they died out. Only small representatives of the fauna remained. It was they who became the ancestors of the modern animal world. This theory is based on iridium. The age of its layer in geological deposits corresponds exactly to 65 million years.
During the Cenozoic, the continents diverged. Each of them formed its own unique flora and fauna. The diversity of marine, flying and land animals has increased significantly in comparison with the Paleozoic. They have become much more advanced, and mammals have taken the dominant position on the planet. In the plant world, higher angiosperms appeared. This is the presence of a flower and an ovule. There were also cereal crops.
The most important thing in the last era is anthropogen or Quaternary, which began 2.6 million years ago. It consists of 2 epochs: the Pleistocene (2.6 million years - 11.7 thousand years) and the Holocene (11.7 thousand years - our time). During the Pleistocene era mammoths, cave lions and bears, marsupial lions, saber-toothed cats and many other animal species that became extinct at the end of the era lived on Earth. 300 thousand years ago, a man appeared on the blue planet. It is believed that the first Cro-Magnons chose for themselves the eastern regions of Africa. At the same time, Neanderthals lived on the Iberian Peninsula.
Notable for the Pleistocene and Ice Ages. For a whole 2 million years, very cold and warm periods of time alternated on Earth. Over the past 800 thousand years, there have been 8 ice ages with an average duration of 40 thousand years. In cold times, glaciers advanced on the continents, and receded in interglacials. At the same time, the level of the World Ocean was rising. About 12 thousand years ago, already in the Holocene, another ice age ended. The climate became warm and humid. Thanks to this, humanity has settled all over the planet.
The Holocene is an interglacial. It has been going on for 12 thousand years. Human civilization has been developing for the last 7 thousand years. The world has changed in many ways. Significant transformations, thanks to the activities of people, have undergone flora and fauna. Today, many animal species are on the verge of extinction. Man has long considered himself the ruler of the world, but the eras of the Earth have not disappeared. Time continues its steady course, and blue planet faithfully revolves around the Sun. In a word, life goes on, but what will happen next - the future will show.
The article was written by Vitaly Shipunov
And the universe. For example, the hypotheses of Kant - Laplace, O.Yu. Schmidt, Georges Buffon, Fred Hoyle and others. But most scientists tend to believe that the Earth is about 5 billion years old.
The unified international geochronological scale gives an idea of the events of the geological past in their chronological sequence. Its main divisions are the eras: Archean, Proterozoic, Paleozoic, Mesozoic. Cenozoic. The oldest interval of geological time (Archaean and Proterozoic) is also called the Precambrian. It covers big period- almost 90% of the total (absolute age of the planet, according to modern ideas, is taken equal to 4.7 billion years).
Within the eras, smaller time intervals are distinguished - periods (for example, the Paleogene, Neogene and Quaternary in the Cenozoic era).
In the Archean era (from the Greek - original, ancient), crystalline rocks (granites, gneisses, schists) were formed. In this era, powerful mountain-building processes took place. The study of this era allowed geologists to assume the presence of the seas and living organisms in them.
Proterozoic era (era early life) is characterized by rock deposits in which the remains of living organisms are found. During this era, the most stable areas, platforms, formed on the surface of the Earth. Platforms - these ancient cores - became the centers of formation.
Paleozoic era (era ancient life) is distinguished by several stages of powerful mountain building, . In this era, the Scandinavian mountains, the Urals, Tien Shan, Altai, Appalachians arose. At this time, animal organisms with a solid skeleton appeared. Vertebrates first appeared: fish, amphibians, reptiles. Ground vegetation appeared in the Middle Paleozoic. Tree ferns, club mosses, and others served as material for the formation of coal deposits.
The Mesozoic era (the era of middle life) is also characterized by intense folding. Mountains formed in areas adjacent to. Reptiles dominated among animals (dinosaurs, proterosaurs, etc.), birds and mammals first appeared. The vegetation consisted of ferns, conifers, angiosperms appeared at the end of the era.
In the Cenozoic era (the era of new life), the modern distribution of continents and oceans takes shape, and intense mountain-building movements take place. Mountain ranges form along the coast Pacific Ocean, in the south of Europe and Asia (, the Himalayas, the Cordillera Coast Ranges, etc.). At the beginning of the Cenozoic era, the climate was much warmer than today. However, the increase in land area due to the rise of the continents led to a cooling. Extensive ice sheets appeared in the north and. This led to significant changes in the flora and fauna. Many animals have died out. Plants and animals appeared close to modern ones. At the end of this era, man appeared and began to intensively populate the land.
The first three billion years of the development of the Earth led to the formation of land. According to the ideas of scientists, at first there was one continent on Earth, which subsequently split into two, and then another division took place, and as a result, five continents have formed by today.
The last billion years of the Earth's history is associated with the formation of folded regions. At the same time, several tectonic cycles (epochs) are distinguished in the geological history of the last billion years: Baikal (end of the Proterozoic), Caledonian (early Paleozoic), Hercynian (late Paleozoic), Mesozoic (Mesozoic), Cenozoic or Alpine cycle (from 100 million years to present tense).
As a result of all the above processes, the Earth acquired a modern structure.
To understand what era it is, you need to look at the decision of the II session of the International Geological Congress, held in 1881. Then scientists argued about our planet. There were several points of view, which brought confusion to science. By a general vote of experts, it was decided that the modern geological era is Cenozoic. It began 66 million years ago and continues to this day.
Features of the Cenozoic
Of course, the modern geological era is not something monolithic and monotonous. It is divided into three Neogene and Quaternary. During this time, the world has changed dramatically. In the early stages of the Cenozoic, the Earth looked completely different from what it is today, including in terms of flora and fauna. However, it was then that several events took place, as a result of which the planet became what we know it to be.
The restructuring of the worldwide system of interconnected sea currents began. It was caused by unprecedented continental drift. Its consequence was the complication of heat exchange between the equatorial and polar basins.
continental drift
In the Paleogene, the Gondwana supercontinent broke apart. An important event that marked the modern geological era was the collision of India and Asia. Africa from the southwest "stuck" into Eurasia. This is how the southern mountains of the Old World and Iran appeared. Geological periods passed slowly, but the map of the Earth inexorably became similar to today's.
The ancient Tethys Ocean, which separated northern Laurasia and southern Gondwana, disappeared over time. Today, only the seas (Mediterranean, Black and Caspian) remained from it. Important events also took place in the Southern Hemisphere. Antarctica broke away from Australia and headed towards the pole, turning into a glacial desert. The Isthmus of Panama appeared, which connected South and North America, finally dividing the Pacific and Atlantic oceans.
Paleogene
The first period that opened the modern geological era is the Paleogene (66-23 million years ago). Has begun new stage development of the organic world. The boundary of the Mesozoic and Cenozoic was marked by the mass extinction of a huge number of species. Most people know this disaster from the extinction of the dinosaurs.
The Mesozoic inhabitants of the Earth were replaced by new mollusks, bony fish and angiosperms. In previous geological periods, reptiles dominated the land. Now they have lost their leading positions to mammals. Of the reptiles, only crocodiles, turtles, snakes, lizards and some other species have survived. The modern appearance of amphibians was formed. Birds dominated the air.
Neogene
The generally accepted sequence of geological eras says that the second period of the Cenozoic era was the Neogene, which replaced the Paleogene and preceded the Quaternary period. It began 23 million years ago and ended 1.65 million years ago.
At the end of the Neogene, the organic world finally took on modern features. Discocyclines, assilins and nummulites became extinct in the sea. The composition of the organic world on land has changed greatly. Mammals have adapted to life in the steppes, dense forests, semi-steppes and semi-deserts, thus colonizing huge territories. It was in the Neogene that proboscis, ungulates, and other representatives of the fauna common today (hyenas, bears, martens, badgers, dogs, rhinos, sheep, bulls, etc.) appeared. Primates emerged from the forests and populated the open spaces. 5 million years ago, the first ancestors of modern man from the genus hominids appeared. In the northern latitudes, heat-loving forms of flora (myrtle, laurel, palm trees) began to disappear.
Formation of modern mountains and seas
In the Neogene, the process of mountain building continued, which determined the modern landscape of the planet. In America, the Cordilleras and Appalachians were formed, in Africa - the Atlas. Mountains appeared in the east of Australia and in Hindustan. Marginal seas (the Sea of Japan and the Sea of Okhotsk) arose in the western Pacific Ocean. Volcanoes were active, volcanic arcs rose from the water.
For some time the level of the World Ocean exceeded the present level, but by the end of the Neogene it fell again. Glaciation swept not only Antarctica, but also the Arctic. The climate became more and more unstable and contrasting, which was especially characteristic of the next Quaternary period.
fauna migration
In the Neogene period, the territories finally united into an integral space. There was a Mediterranean route between Africa and Europe. The Turgai Sea disappeared from the West Siberian Lowland. It separated Europe from Asia. After it dried, migration between different parts of the world was facilitated. Herbivorous horses came from America, and antelopes and bulls came from Asia. Proboscis spread outside of Africa. Cats, which at first were saber-toothed and lived only in America, flooded Eurasia.
The Isthmus of Panama formed 4 million years ago. There was a land connection between the two Americas, which led to an unprecedented migration of animals. The southern fauna throughout the entire Cenozoic was in a state of isolation, actually living on a huge island. Now, species unfamiliar to each other have come into contact. The fauna is mixed. Armadillos, sloths and marsupials showed up in the north. Horses, tapirs, hamsters, pigs, deer and camelids (llamas) colonized South America. Northern animal world enriched. But in South America there was a real disaster. Due to new competitors in the face of ungulates and predators, many rodents and marsupials died out. These controversial events became known as the Great American Exchange.
Quaternary period
It took several billion years for numerous geological eras and periods to replace each other and finally come to the point when the Quaternary period of the Cenozoic began one and a half million years ago. It continues to this day, so it can be considered modern.
All periods and eras of geological history differ from each other in unique features. The Quaternary is also called the anthropogen, since it was during this period of time that the development and formation of man took place. His first ancestors appeared in East Africa. Then they settled in Eurasia, and from modern Chukotka they came to America. People have gone through several stages of development. The last one (homo sapiens) came 40 thousand years ago.
At the same time, it is unique in its climatic jumps. Over the past million years, several ice ages have passed, changing to warming. Climatic troubles have led to the extinction of many heat-loving species of flora and fauna. Animals that adapted to life in the conditions of the ice age (mammoths, saber-toothed tigers) also disappeared.
Holocene
The answer to the question of what era is now has already been found (Cenozoic). At the same time, within its framework, the Quaternary period continues today. It is also divided into parts. The modern division of the Quaternary period is the Holocene epoch. It began 12 thousand years ago. Scientists call it interglacial. That is, this is the period that has come after a significant warming.
At the same time, modern mankind managed to catch several small ice ages. Climatic changes, characteristic of the entire Quaternary period, have been cyclically repeated several times over the past 12 thousand years. At the same time, in terms of its scale, remaining miniature and not so much cardinal. Climatologists note the Little Ice Age, which occurred in 1450-1850. Winter temperatures in Europe have dropped, leading to frequent crop failures and turmoil in the agricultural economy. The Little Ice Age was preceded by the Atlantic Optimum (900-1300). During this period, the climate was noticeably milder, and the glaciers were significantly reduced. It should be remembered here that the Vikings, who discovered Greenland in the Middle Ages, called it a "green country", although today it is not at all "green".
Humanity has fallen victim to a terrible pandemic caused by a mysterious fungus that enters into symbiosis with the human brain. The infected turn into zombies that feed on the meat of living beings, including healthy people. The remaining uninfected people live in several military bases. They're trying to create an antidote. To do this, they are engaged in the study of mutant children born from infected mothers. These children are intelligent like humans, but their eating habits are identical to those of zombies. Children are kept in cells, fed with worms. They are taught by being brought to classes in wheelchairs, shackled hand and foot, under escort of armed soldiers. Classes with them are conducted by Helen Justinov, who treats mutant children like ordinary children. One of her wards, Melanie, literally idolizes the teacher. However, when Helen comes to Melanie's cell and tries to free her from handcuffs (the girl was left in chains for the night as punishment), she almost eats her benefactor.
The next day, Sergeant Eddie Pax takes Melanie in a wheelchair to the lab. Along the way, they see how crowds of zombies are trying to break into the base. Melanie is brought to the laboratory, where Dr. Caroline Caldwell is going to dissect a mutant to make a drug from her brain that gives people immunity against a pathogenic fungus. Justinov bursts into the laboratory, she tries to disrupt the operation. Zombies break through there, having penetrated the guarded perimeter. Melanie frees herself and goes outside. She sees crowds of zombies attacking base personnel. Two soldiers - Sergeants Kieran Gallagher and Eddie Pax - managed to get into an armored van and want to leave the base. Dr. Caldwell is with them. Melanie saves the Justins from the zombies, they also get into the van, which takes them away from the zombies. The military wants to shoot Melanie, but Helen won't let them. She is supported by Dr. Caldwell: Melanie remains her last hope for a vaccine.
So that Melanie does not attack people from hunger, they put a mask on her and shackle her with handcuffs. The van stops in the woods, where people are trying to draw water from a stream. They are attacked by zombies, Pax takes the wagon out of the forest. People are trying to contact the headquarters, but they cannot pick up a radio signal. The van travels to London in search of food.
There are crowds of zombies on the streets of the city. While there is nothing living nearby, they fall into a trance, from which they can be awakened by the smell of a living being, a sudden movement or a loud noise. People smear their bodies with a special cream that fights off the smell of a person, and go to the city, trying not to make sudden movements and not make noise. They go through dense ranks of zombies. At this moment, Caldwell notices a female zombie carrying a stroller, in which you can see the legs of a small child under a pile of rags. Caldwell had not noticed maternal instincts in zombies before. She brakes the stroller, throws the rags aside and sees the rats, which have already eaten most of the child's corpse. The woman involuntarily screams, this sound brings the zombie out of a trance. People have to run, firing back from the zombies. They take refuge in an abandoned building, try to get in touch with the headquarters, again without result. Melanie asks Caldwell where she came from. She says that the military during the raid found a group of mutant children in the maternity hospital. There they also found the corpses of their mothers with their entrails eaten away. Women fall prey to the fungus while already pregnant. Babies infected through the placenta ate their way out. Melanie is one of them.
Pax discovers that there are hordes of zombies around the building. They reacted to the sound and blocked the building. If only they were distracted by a running cat! Melanie asks to go outside. She's hungry, and zombies don't feed on their own kind. Melanie is released. She catches a cat in the alley and satisfies her hunger. Then she goes into some apartment and finds a dog there. Melanie picks up the animal, carries it to the blocked building, and releases it. A crowd of zombies rushes after the dog. The path is clear. People move on. They discover that sprouts are making their way from the bodies of dead zombies. This is the next stage in the development of the fungus. On the branches of the plant boxes with spores. Caldwell says that if these tough boxes break open, the spores will infect all the surviving people.
People discover a mobile laboratory. It is armored, it has a gateway. Pax tries to start the engine. Gallagher goes out in search of food. Melanie also goes hunting. She catches a dove and satisfies her hunger. In one of the buildings, Melanie discovers a group of wild mutant children, they do not have the skills of articulate speech. It becomes clear to Melanie that the kids have tracked down Gallagher. She runs to the lab and informs Pax that Gallagher needs help. But it's' too late. The children lured the sergeant into a trap and killed him. Pax, Melanie and Justinov come to this place. They are blocked by a pack of predatory children. The sergeant is about to open fire, but is stopped by Melanie. She will deal with the predators herself. Melanie confronts the leader of the mutant children, defeats him and takes Pax and Justins away. They return to the lab, where they are rendered unconscious by Caldwell with a sleeping gas. She wants to extract Melanie's brain. But the girl knows how to hold her breath and remains conscious. The doctor persuades Melanie to sacrifice herself for the Justins (Caldwell herself will soon die of blood poisoning), but the girl goes outside, goes to the mutant plant and sets it on fire. Under the influence of high temperature, the spore boxes open. Pax comes out of the lab to look for Melanie. He becomes infected with spores and asks the girl to shoot him. She does his will.
Caldwell is eaten by hungry mutant children, leaving only Justin alive. Helen lives in a sealed lab and trains wild mutant children brought to her by Melanie.
The history of our planet still holds many mysteries. Scientists from various fields of natural science have contributed to the study of the development of life on Earth.
It is believed that the age of our planet is about 4.54 billion years. This entire time period is usually divided into two main stages: Phanerozoic and Precambrian. These stages are called eons or eonoteme. Eons, in turn, are divided into several periods, each of which is distinguished by a set of changes that have taken place in the geological, biological, atmospheric state of the planet.
- Precambrian, or Cryptozoic- this is an eon (time interval of the development of the Earth), covering about 3.8 billion years. That is, the Precambrian is the development of the planet from the moment of formation, the formation of the earth's crust, the proto-ocean and the emergence of life on Earth. By the end of the Precambrian, highly organized organisms with a developed skeleton were already widespread on the planet.
The eon includes two more eonotemes - katarche and archaea. The latter, in turn, includes 4 eras.
1. Katarchaeus- this is the time of the formation of the Earth, but there was still neither the core nor the earth's crust. The planet was still cold space body. Scientists suggest that during this period there was already water on Earth. The Catarchean lasted about 600 million years.
2. Archaea covers a period of 1.5 billion years. During this period, there was no oxygen on Earth yet, deposits of sulfur, iron, graphite, and nickel were being formed. The hydrosphere and the atmosphere were a single vapor-gas shell, which enveloped in a dense cloud Earth. The sun's rays practically did not penetrate through this veil, so darkness reigned on the planet. 2.1 2.1. Eoarchean- this is the first geological era, which lasted about 400 million years. The most important event of the Eoarchean is the formation of the hydrosphere. But there was still little water, the reservoirs existed separately from each other and did not yet merge into the world ocean. At the same time Earth's crust becomes solid, although asteroids are still bombarding the Earth. At the end of the Eoarchean, the first supercontinent in the history of the planet, Vaalbara, is formed.
2.2 Paleoarchaean- the next era, which also lasted approximately 400 million years. During this period, the core of the Earth is formed, tension increases magnetic field. A day on the planet lasted only 15 hours. But the oxygen content in the atmosphere increases due to the activity of bacteria that have appeared. The remains of these first forms of the Paleoarchean era of life have been found in Western Australia.
2.3 Mesoarchean also lasted about 400 million years. In the Mesoarchean era, our planet was covered by a shallow ocean. Land areas were small volcanic islands. But already during this period, the formation of the lithosphere begins and the mechanism of plate tectonics starts. At the end of the Mesoarchean, the first ice age occurs, during which snow and ice form for the first time on Earth. Biological species are still represented by bacteria and microbial life forms.
2.4 Neoarchean- the final era of the Archean eon, the duration of which is about 300 million years. Colonies of bacteria at this time form the first stromatolites (limestone deposits) on Earth. The most important event of the Neoarchean is the formation of oxygen photosynthesis.
II. Proterozoic- one of the longest time periods in the history of the Earth, which is usually divided into three eras. During the Proterozoic, the ozone layer first appears, the world ocean reaches almost its present volume. And after the longest Huron glaciation, the first multicellular life forms appeared on Earth - mushrooms and sponges. The Proterozoic is usually divided into three eras, each of which contained several periods.
3.1 Paleo-Proterozoic- the first era of the Proterozoic, which began 2.5 billion years ago. At this time, the lithosphere is fully formed. But the former forms of life, due to the increase in oxygen content, practically died out. This period is called the oxygen catastrophe. By the end of the era, the first eukaryotes appear on Earth.
3.2 Mesoproterozoic lasted approximately 600 million years. The most important events of this era: the formation of continental masses, the formation of the supercontinent Rodinia and the evolution of sexual reproduction.
3.3 Neo-proterozoic. During this era, Rodinia breaks up into about 8 parts, the super-ocean of Mirovia ceases to exist, and at the end of the era, the Earth is covered with ice almost to the equator. In the Neoproterozoic era, living organisms for the first time begin to acquire a hard shell, which will later serve as the basis of the skeleton.
III. Paleozoic- the first era of the Phanerozoic eon, which began approximately 541 million years ago and lasted about 289 million years. This is the era of the emergence of ancient life. The supercontinent Gondwana unites the southern continents, a little later the rest of the land joins it and Pangea appears. are starting to take shape climatic zones, and the flora and fauna are represented mainly by marine species. Only towards the end of the Paleozoic does the development of land begin, and the first vertebrates appear.
The Paleozoic era is conditionally divided into 6 periods.
1. Cambrian period lasted 56 million years. During this period, the main rocks are formed, the mineral skeleton appears in living organisms. And the most important event of the Cambrian is the appearance of the first arthropods.
2. Ordovician period- the second period of the Paleozoic, which lasted 42 million years. This is the era of the formation of sedimentary rocks, phosphorites and oil shale. The organic world of the Ordovician is represented by marine invertebrates and blue-green algae.
3. Silurian period covers the next 24 million years. At this time, almost 60% of living organisms that existed before die out. But the first cartilaginous and bone fish in the history of the planet appear. On land, the Silurian is marked by the appearance of vascular plants. Supercontinents converge and form Laurasia. By the end of the period, ice melting was noted, the sea level rose, and the climate became milder.
4 Devonian is characterized by the rapid development of various forms of life and the development of new ecological niches. Devon covers a time interval of 60 million years. The first terrestrial vertebrates, spiders, and insects appear. Land animals develop lungs. Although fish still dominate. The kingdom of flora of this period is represented by ferns, horsetails, club mosses and gosperms.
5. Carboniferous period often referred to as carbon. At this time, Laurasia collides with Gondwana and the new supercontinent Pangea appears. A new ocean is also formed - Tethys. This is the time when the first amphibians and reptiles appeared.
6. Permian period- the last period of the Paleozoic, which ended 252 million years ago. It is believed that at this time a large asteroid fell to Earth, which led to significant climate change and the extinction of almost 90% of all living organisms. Most of the land is covered with sand, the most extensive deserts appear that have only existed in the entire history of the Earth's development.
IV. Mesozoic- the second era of the Phanerozoic eon, which lasted almost 186 million years. At this time, the continents acquire almost modern outlines. A warm climate contributes to the rapid development of life on Earth. Giant ferns disappear, and angiosperms appear to replace them. The Mesozoic is the era of dinosaurs and the appearance of the first mammals.
The Mesozoic era is divided into three periods: Triassic, Jurassic and Cretaceous.
1. Triassic period lasted a little over 50 million years. At this time, Pangea begins to split, and the inland seas gradually become smaller and dry up. The climate is mild, the zones are not pronounced. Nearly half of land plants are disappearing as deserts spread. And in the realm of fauna, the first warm-blooded and terrestrial reptiles appear, which became the ancestors of dinosaurs and birds.
2 Jurassic covers a gap of 56 million years. A humid and warm climate reigned on Earth. The land is covered with thickets of ferns, pines, palms, cypresses. Dinosaurs reign on the planet, and numerous mammals have so far been distinguished by their small stature and thick hair.
3 Cretaceous- the longest period of the Mesozoic, lasting almost 79 million years. The split of the continents is practically coming to an end, the Atlantic Ocean is significantly increasing in volume, and ice sheets are forming at the poles. An increase in the water mass of the oceans leads to the formation of a greenhouse effect. At the end of the Cretaceous, a catastrophe occurs, the causes of which are still not clear. As a result, all dinosaurs and most species of reptiles and gymnosperms became extinct.
V. Cenozoic- this is the era of animals and Homo sapiens, which began 66 million years ago. The continents at that time acquired their modern shape, Antarctica occupied South Pole Earth, and the oceans continued to grow. Plants and animals that survived the catastrophe of the Cretaceous period found themselves in a completely new world. Unique communities of lifeforms began to form on each continent.
The Cenozoic era is divided into three periods: Paleogene, Neogene and Quaternary.
1. Paleogene period ended approximately 23 million years ago. At that time, a tropical climate reigned on Earth, Europe was hiding under evergreen tropical forests, and deciduous trees grew only in the north of the continents. It was during the Paleogene period that the rapid development of mammals takes place.
2. Neogene period covers the next 20 million years of the planet's development. Whales and bats appear. And, although saber-toothed tigers and mastodons still roam the earth, the fauna is increasingly acquiring modern features.
3. Quaternary period began more than 2.5 million years ago and continues to this day. Two major events characterize this time period: the ice age and the appearance of man. The Ice Age completely completed the formation of the climate, flora and fauna of the continents. And the appearance of man marked the beginning of civilization.
