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 spaceships with representatives of the universal mind rushed through this substance at great speed. 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 of a 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 are 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 the plant world, algae predominated at first. During Silurian plants began to colonize the land. At the beginning 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. AT 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 the 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. This was due to the improvement of the nervous system and 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

After the fall, there was an explosion of great force. 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 the blue planet conscientiously 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

The Phanerozoic eon is a part of geological time, starting about 542 million years ago and continuing to the present. Compared to the previous one (part of the geological history of the planet, including such eons as,), Phanerozoic is also famous for its abundance of worlds.

Eras and periods

Phanerozoic is divided into three eras, which in turn consist of periods:

Palaeozoic

Mesozoic era

Cenozoic era

Geography

During the Phanerozoic, the continents drifted and eventually coalesced into a single supercontinent known as Pangea, and then split into the current parts of the world.

Some scientists believe that the Phanerozoic eon began shortly after the collapse of a hypothetical supercontinent at the end of the global ice age. During the early Paleozoic era, there were a significant number of relatively small continents. By the end of the Paleozoic, the continents had come together to form the supercontinent Pangea, which included most of the earth's landmass.

The Mesozoic era was characterized by the dramatic division of Pangea into the northern continent of Laurasia and the southern continent of Gondwana. By the end of the era, the continents had practically taken on their current form. Laurasia became North America and Eurasia, and Gondwana split into South America, Africa, Australia, Antarctica, and the Indian subcontinent.

The Cenozoic era is the geological time interval during which the continents took their current positions. Australia and New Guinea broke away from Gondwana. Antarctica is located above the South Pole. The Atlantic Ocean expanded, and a little later South America joined North America.

Climate

During the Phanerozoic eon, the Earth's climate varied between conditions that supported global continental glaciation and rather tropical conditions with no permanent ice caps even at the poles. The difference in global average temperatures between full ice ages and non-glacial periods is estimated to be around 10º C, although much larger changes have been observed at high latitudes, and smaller at low latitudes.

The evolution of CO2-consuming (and oxygen-producing) organisms in the Precambrian led to the creation of the atmosphere as it is today, although for most of the Phanerozoic it had CO2 levels much higher than today. Similarly, the Earth's average temperature has often been warmer than it is at present.

A life

Before the Paleozoic period, there was no atmosphere, as there is today. When the amount of oxygen began to increase, the ozone layer formed. At high altitude, oxygen molecules are destroyed by the ultraviolet radiation of the sun. These oxygen molecules join together to create ozone.

A thick layer of ozone exists at an altitude of 15 to 35 kilometers. This layer ensures that harmful radiation from the sun does not reach the earth's surface. The thicker the ozone layer, the less dangerous ultraviolet radiation reaches the Earth. Before this protective function developed, animals primarily used. Consequently, the Phanerozoic flora and fauna were able to colonize the land. Early plants grew on land during the Silurian (about 430 million years ago). These were vascular plants such as ferns. Several species arose very quickly.

They appeared in the Devonian, and reptiles appeared in the Carboniferous period. At the border of the Triassic and Jurassic (200 million years ago), mammals first appeared and, finally, birds. Mammals became the dominant animals after the extinction of the dinosaurs at the end of the Cretaceous period (66 million years ago).

is the totality of all forms of the earth's surface. They can be horizontal, inclined, convex, concave, complex.

The height difference between the highest peak on land, Mount Chomolungma in the Himalayas (8848 m), and the Mariana Trench in the Pacific Ocean (11,022 m) is 19,870 m.

How was the relief of our planet formed? In the history of the Earth, two main stages of its formation are distinguished:

• planetary(5.5-5.0 million years ago), which ended with the formation of the planet, the formation of the core and mantle of the Earth;
• geological, which began 4.5 million years ago and continues to this day. It was at this stage that the formation of the earth's crust occurred.

The source of information about the development of the Earth during the geological stage is primarily sedimentary rocks, which in the vast majority were formed in the aquatic environment and therefore occur in layers. The deeper the layer lies from the earth's surface, the earlier it was formed and, therefore, is more ancient with respect to any layer that is closer to the surface and is younger. This simple reasoning is based on the concept relative age of rocks, which formed the basis for the construction geochronological table(Table 1).

The longest time intervals in geochronology are − zones(from Greek. aion- century, epoch). There are such zones as: cryptozoic(from Greek. cryptos- hidden and zoe- life), covering the entire Precambrian, in the deposits of which there are no remains of skeletal fauna; phanerozoic(from Greek. phaneros- explicit, zoe- life) - from the beginning of the Cambrian to our time, with a rich organic life, including skeletal fauna. The zones are not equal in duration, so if the Cryptozoic lasted 3-5 billion years, then the Phanerozoic lasted 0.57 billion years.

Table 1. Geological table

Era. letter designation, duration	The main stages of the development of life	Periods, letter designation, duration	major geological events. The shape of the earth's surface	Most Common Minerals
Cenozoic, KZ, about 70 Ma	dominance of angiosperms. The rise of the mammalian fauna. The existence of natural zones close to modern ones, with repeated displacements of boundaries	Quaternary, or Anthropogenic, Q, 2 million years	General uplift of the territory. repeated glaciations. The appearance of man	Peat. Alluvial deposits of gold, diamonds, precious stones
		Neogene, N, 25 Ma	The emergence of young mountains in the areas of Cenozoic folding. The revival of mountains in the regions of all ancient foldings. Dominance of angiosperms (flowering) plants	Brown coals, oil, amber
		Paleogene, P, 41 Ma	Destruction of the Mesozoic mountains. Wide distribution of flowering plants, development of birds and mammals	Phosphorites, brown coals, bauxites
Mesozoic, MZ, 165 Ma		Cretaceous, K, 70 Ma	The emergence of young mountains in the areas of Mesozoic folding. Extinction of giant reptiles (reptiles). Development of birds and mammals	Oil, oil shale, chalk, coal, phosphorites
		Jurassic, J, 50 Ma	Formation of modern oceans. Hot, humid climate. The rise of reptiles. dominance of gymnosperms. Appearance of primitive birds	Coals, oil, phosphorites
		Triassic, T, 45 Ma	The greatest retreat of the sea and the rise of the continents in the entire history of the Earth. Destruction of pre-Mesozoic mountains. Vast deserts. First mammals	rock salts
Paleozoic, PZ, 330 Ma	The flowering of ferns and other spore plants. Time for fish and amphibians	Permian, R, 45 Ma	The emergence of young mountains in areas of Hercynian folding. Dry climate. The emergence of gymnosperms	Rock and potash salts, gypsum
		Carboniferous (Carboniferous), C, 65 Ma	Widespread swampy lowlands. Hot, humid climate. Development of forests from tree ferns, horsetails and club mosses. The first reptiles The heyday of amphibians	Abundance of coal and oil
		Devonian, D, 55 million years	Reduction of the seas. Hot climate. First deserts. The appearance of amphibians. Numerous fish	Salt, oil
	The appearance of animals and plants on Earth	Silurian, S, 35 Ma	The emergence of young mountains in the areas of the Caledonian folding. The first land plants
		Ordovician, O, 60 Ma	Decrease in the area of ​​marine basins. Appearance of the first terrestrial invertebrates
		Cambrian, E, 70 Ma	The emergence of young mountains in the areas of Baikal folding. Flooding of vast areas by the seas. The rise of marine invertebrates	Rock salt, gypsum, phosphate rock
Proterozoic, PR. about 2000 Ma	Origin of life in water. Bacteria and algae time		Beginning of the Baikal folding. Powerful volcanism. Bacteria and algae time	Huge reserves of iron ores, mica, graphite
Archean, AR. over 1000 million years			Ancient folding. Intense volcanic activity. Time of primitive bacteria	Iron ores

The zones are divided into era. In the cryptozoic, there are Archean(from Greek. archaios- primordial, ancient aion- century, era) and Proterozoic(from Greek. proteros- earlier, zoe - life) era; in the Phanerozoic Paleozoic(from Greek ancient and life), Mesozoic(from Greek. tesos - middle, zoe - life) and Cenozoic(from Greek. kainos- new, zoe - life).

Eras are divided into shorter periods of time - periods established only for the Phanerozoic (see Table 1).

The main stages in the development of the geographical envelope

The geographical envelope has come a long and difficult path of development. There are three qualitatively different stages in its development: pre-biogenic, biogenic, and anthropogenic.

pre-biogenic stage(4 billion - 570 million years) - the longest period. At this time, the process of increasing the thickness and complicating the composition of the earth's crust took place. By the end of the Archean (2.6 billion years ago), a continental crust about 30 km thick had already formed over vast expanses, and in the Early Proterozoic, protoplatforms and protogeosynclines separated. During this period, the hydrosphere already existed, but the volume of water in it was less than now. Of the oceans (and then only by the end of the early Proterozoic) one took shape. The water in it was salty and the salinity level most likely was about the same as now. But, apparently, in the waters of the ancient ocean, the predominance of sodium over potassium was even greater than now, there were also more magnesium ions, which is associated with the composition of the primary earth's crust, the weathering products of which were carried into the ocean.

The Earth's atmosphere at this stage of development contained very little oxygen, and there was no ozone screen.

Life most likely existed from the very beginning of this stage. According to indirect data, microorganisms lived already 3.8-3.9 billion years ago. The discovered remains of the simplest organisms are 3.5-3.6 billion years old. However, from the moment of its inception to the very end of the Proterozoic, organic life did not play a leading, determining role in the development of the geographical envelope. In addition, many scientists deny the presence of organic life on land at this stage.

The evolution of organic life to the pre-biogenic stage proceeded slowly, but nevertheless, 650-570 million years ago, life in the oceans was quite rich.

Biogenic stage(570 million - 40 thousand years) lasted during the Paleozoic, Mesozoic and almost the entire Cenozoic, with the exception of the last 40 thousand years.

The evolution of living organisms during the biogenic stage was not smooth: eras of relatively calm evolution were replaced by periods of rapid and deep transformations, during which some forms of flora and fauna died out and others became widespread.

Simultaneously with the appearance of terrestrial living organisms, soils began to form in our modern understanding.

Anthropogenic stage began 40 thousand years ago and continues today. Although man as a biological species appeared 2-3 million years ago, his impact on nature for a long time remained extremely limited. With the advent of Homo sapiens, this impact has increased significantly. It happened 38-40 thousand years ago. From here the anthropogenic stage in the development of the geographic envelope takes its countdown.

Life on Earth originated over 3.5 billion years ago, immediately after the completion of the formation of the earth's crust. Throughout time, the emergence and development of living organisms influenced the formation of relief and climate. Also, tectonic and climatic changes that have taken place over the years have influenced the development of life on Earth.

A table of the development of life on Earth can be compiled based on the chronology of events. The entire history of the Earth can be divided into certain stages. The largest of them are the eras of life. They are divided into eras, eras - into - into eras, eras - into centuries.

Ages of life on earth

The entire period of the existence of life on Earth can be divided into 2 periods: the Precambrian, or Cryptozoic (primary period, 3.6 to 0.6 billion years), and Phanerozoic.

Cryptozoic includes the Archean (ancient life) and Proterozoic (primary life) eras.

Phanerozoic includes the Paleozoic (ancient life), Mesozoic (middle life) and Cenozoic (new life) eras.

These 2 periods of development of life are usually divided into smaller ones - eras. The boundaries between eras are global evolutionary events, extinctions. In turn, eras are divided into periods, periods - into epochs. The history of the development of life on Earth is directly related to changes in the earth's crust and the planet's climate.

Era of development, countdown

It is customary to single out the most significant events in special time intervals - eras. Time is counted backwards, from ancient life to the new. There are 5 eras:

1. Archean.
2. Proterozoic.
3. Paleozoic.
4. Mesozoic.
5. Cenozoic.

Periods of development of life on Earth

The Paleozoic, Mesozoic and Cenozoic eras include periods of development. These are smaller periods of time, compared to eras.

Palaeozoic:

• Cambrian (Cambrian).
• Ordovician.
• Silurian (Silur).
• Devonian (Devonian).
• Carboniferous (carbon).
• Perm (Perm).

Mesozoic era:

• Triassic (Triassic).
• Jura (Jurassic).
• Cretaceous (chalk).

Cenozoic era:

• Lower Tertiary (Paleogene).
• Upper Tertiary (Neogene).
• Quaternary, or anthropogen (human development).

The first 2 periods are included in the Tertiary period lasting 59 million years.

Table of the development of life on Earth

era, period	Duration	Live nature	Inanimate nature, climate
Archean era (ancient life)	3.5 billion years	The appearance of blue-green algae, photosynthesis. Heterotrophs	The predominance of land over the ocean, the minimum amount of oxygen in the atmosphere.
Proterozoic era (early life)	2.7 Ga	The appearance of worms, mollusks, the first chordates, soil formation.	The land is a stone desert. Accumulation of oxygen in the atmosphere.
The Paleozoic era includes 6 periods:
1. Cambrian (Cambrian)	535-490 Ma	development of living organisms.	Hot climate. The dry land is deserted.
2. Ordovician	490-443 Ma	The emergence of vertebrates.	Flooding of almost all platforms with water.
3. Silurian (Silur)	443-418 Ma	Exit of plants to land. Development of corals, trilobites.	with the formation of mountains. The seas prevail over the land. The climate is varied.
4. Devonian (Devonian)	418-360 Ma	The appearance of fungi, lobe-finned fish.	Formation of intermountain depressions. The predominance of a dry climate.
5. Carboniferous (carbon)	360-295 Ma	Appearance of the first amphibians.	The sinking of the continents with the flooding of territories and the emergence of swamps. The atmosphere contains a lot of oxygen and carbon dioxide.
6. Perm (Perm)	295-251 Ma	Extinction of trilobites and most amphibians. The beginning of the development of reptiles and insects.	Volcanic activity. Hot climate.
The Mesozoic era includes 3 periods:
1. Triassic (Triassic)	251-200 Ma	Gymnosperm development. The first mammals and bony fishes.	Volcanic activity. Warm and sharply continental climate.
2. Jurassic (Jurassic)	200-145 Ma	The emergence of angiosperms. The spread of reptiles, the appearance of the first bird.	Mild and warm climate.
3. Cretaceous (chalk)	145-60 Ma	The appearance of birds, higher mammals.	Warm climate followed by cooling.
The Cenozoic era includes 3 periods:
1. Lower Tertiary (Paleogene)	65-23 Ma	The flowering of angiosperms. The development of insects, the appearance of lemurs and primates.	Mild climate with the allocation of climatic zones.
2. Upper Tertiary (Neogene)	23-1.8 Ma	The emergence of ancient people.	Dry climate.
3. Quaternary or anthropogen (human development)	1.8-0 Ma	The appearance of man.	Cooling.

The development of living organisms

The table of the development of life on Earth involves the division not only into time intervals, but also into certain stages of the formation of living organisms, possible climatic changes (ice age, global warming).

• Archean era. The most significant changes in the evolution of living organisms are the appearance of blue-green algae - prokaryotes capable of reproduction and photosynthesis, the emergence of multicellular organisms. The appearance of living protein substances (heterotrophs) capable of absorbing organic substances dissolved in water. In the future, the appearance of these living organisms made it possible to divide the world into flora and fauna.

• Mesozoic era.

• Triassic. Distribution of plants (gymnosperms). An increase in the number of reptiles. The first mammals, bony fish.
• Jurassic period. The predominance of gymnosperms, the emergence of angiosperms. The appearance of the first bird, the flowering of cephalopods.
• Cretaceous period. Spread of angiosperms, reduction of other plant species. The development of bony fish, mammals and birds.

• Cenozoic era.
  • Lower Tertiary period (Paleogene). The flowering of angiosperms. The development of insects and mammals, the appearance of lemurs, later primates.
  • Upper Tertiary period (Neogene). The development of modern plants. The appearance of human ancestors.
  • Quaternary period (anthropogen). Formation of modern plants, animals. The appearance of man.

Development of conditions of inanimate nature, climate change

The table of the development of life on Earth cannot be presented without data on changes in inanimate nature. The emergence and development of life on Earth, new species of plants and animals, all this is accompanied by changes in inanimate nature and climate.

Climate Change: Archean Era

The history of the development of life on Earth began through the stage of the predominance of land over water resources. The relief was poorly outlined. The atmosphere is dominated by carbon dioxide, the amount of oxygen is minimal. Salinity is low in shallow water.

The Archean era is characterized by volcanic eruptions, lightning, black clouds. The rocks are rich in graphite.

Climatic changes during the Proterozoic era

Land is a stone desert, all living organisms live in water. Oxygen accumulates in the atmosphere.

Climate change: the Paleozoic era

During various periods of the Paleozoic era, the following occurred:

• Cambrian period. The land is still deserted. The climate is hot.
• Ordovician period. The most significant changes are the flooding of almost all northern platforms.
• Silurian. Tectonic changes, the conditions of inanimate nature are diverse. Mountain building occurs, the seas prevail over the land. Regions of different climates, including areas of cooling, were determined.
• Devonian. Dry climate prevails, continental. Formation of intermountain depressions.
• Carboniferous period. The sinking of the continents, wetlands. The climate is warm and humid, with a lot of oxygen and carbon dioxide in the atmosphere.
• Permian period. Hot climate, volcanic activity, mountain building, drying up of swamps.

In the Paleozoic era, mountains formed. Such changes in the relief affected the world's oceans - the sea basins were reduced, a significant land area was formed.

The Paleozoic era marked the beginning of almost all major deposits of oil and coal.

Climatic changes in the Mesozoic

The climate of different periods of the Mesozoic is characterized by the following features:

• Triassic. Volcanic activity, the climate is sharply continental, warm.
• Jurassic period. Mild and warm climate. The seas prevail over the land.
• Cretaceous period. Retreat of the seas from the land. The climate is warm, but at the end of the period, global warming is replaced by cooling.

In the Mesozoic era, the previously formed mountain systems are destroyed, the plains go under water (Western Siberia). In the second half of the era, the Cordilleras, the mountains of Eastern Siberia, Indochina, partly Tibet, formed the mountains of the Mesozoic folding. A hot and humid climate prevails, contributing to the formation of swamps and peat bogs.

Climate change - Cenozoic era

In the Cenozoic era, there was a general uplift of the Earth's surface. The climate has changed. Numerous glaciations of the earth covers advancing from the north have changed the appearance of the continents of the Northern Hemisphere. Due to such changes, hilly plains were formed.

• Lower Tertiary period. Mild climate. Division into 3 climatic zones. Formation of continents.
• Upper Tertiary period. Dry climate. The emergence of steppes, savannahs.
• Quaternary period. Multiple glaciation of the northern hemisphere. Climate cooling.

All changes during the development of life on Earth can be written in the form of a table that will reflect the most significant stages in the formation and development of the modern world. Despite the already known methods of research, even now scientists continue to study history, make new discoveries that allow modern society to find out how life developed on Earth before the appearance of man.

GEOCHRONOLOGY (geological reckoning), the doctrine of the chronological sequence of formation and age of rocks that make up the earth's crust. Distinguish:

Relative geochronology uses the principle of sequential rock formation; the so-called. stratigraphic scale with divisions - eonoteme, erathem, etc., which serves as the basis for creating a geochronological scale (sequence of time intervals) with the corresponding divisions - eon, era, period, etc. (see table).

For absolute geochronology, calculated in thousands and millions of years and establishing a radiometric age, the radioactive decay of a number of elements is used, which proceeds at a constant rate and does not change under the influence of external conditions. Absolute geochronology was proposed at the beginning of the 20th century. P. Curie and E. Rutherford. Depending on the final decay products, lead, helium, argon, calcium, strontium and other methods of absolute geochronology, as well as radiocarbon (14 C) are distinguished. In addition, as methods of absolute geochronology, thermoluminescent methods are used (measurement of the physical properties of some crystals, it makes it possible to date the time > 60 thousand years) and paleomagnetic methods.

Cryptozoic eon

PRECAMBRIAN, the most ancient strata of the earth's crust, the formation of which preceded the Cambrian period, and the corresponding period of time, which is 6/7 of the geological history of the Earth. The duration of St. 3.5 billion years. It is subdivided into Archaean and Proterozoic with a boundary between them 2600 million years ago. In the Precambrian, life originated, an oxygen atmosphere arose, but there was no skeletal fauna. The vegetation of the early Precambrian is evidenced by the remains of algal structures (in the form of stromatolites, oncoliths, etc.), organic carbon in carbonate deposits (3.5-4 billion years ago). At the level of 2-2.5 billion years, traces of the vital activity of animals appear, and in the Late Precambrian - their first remains. Several epochs of increased tectono-magmatic activity have been established in the Precambrian. Precambrian deposits are associated with the richest deposits of iron, copper and manganese ores, gold, uranium, and polymetals.

Archean era(>3500 - 2600 Ma)

Approximately 3.5 billion years ago, the formation of the primary continental crust ends, 4-3.5 billion years ago, a mountainous relief of volcanic origin appears. The land is represented by Gondwana and Laurasia. The atmosphere has a much lower density than the modern one, and consists mainly of methane, ammonia, hydrogen, water vapor, hydrogen sulfide, carbon monoxide and dioxide, oxygen is practically absent. The water in the ocean was probably slightly brackish with a predominance of SiO 2 , Fe, Mn, HCO3-, CO2, washed out from the granite layer of the crust and accumulating on the ocean floor in the form of quartzite, jespelite (ferruginous quartzite), limestones, dolomites. There is a climatic zone.

By the beginning of the Archean, the chemical stage ends and the biological stage of the evolution of the biosphere begins. The remains of bacteria and algae (2.7-3.5 billion years) were found in the shales of the North. America, Center. Africa, Australia, in even more ancient rocks Zap. Australia (3.5 billion years) discovered stromatolites (remains of cyanobacteria).

Proterozoic era(2600-570 Ma)

Early (2600-1650 million years): cyanobacteria are actively developing, thanks to the vital activity of which an oxygen environment begins to form. The first multicellular algae appear.

Late (1650-570 million years): the appearance of free oxygen in the atmosphere, the beginning of the formation of the ozone screen. The salinity of oceanic waters is increasing, reaching the present day. The first multicellular animals appear (sponges, jellyfish, worms, archaeocyates) found in the South. Australia.

Riphean (1650-680 million years): the climatic zonality that was outlined earlier is preserved. The oceans are relatively shallow, the predominance of land over the sea, organic life is concentrated in water (on land there are separate colonies of bacteria and fungi).

Vend (680-570 Ma)

PHANEROZOIC AEON

(Phanerozoic) (from the Greek phaneros - explicit and zoe - life), the largest stage of geological history, covering the Paleozoic, Mesozoic and Cenozoic eras, the duration of 570 million years. It was distinguished in 1930 by the American geologist J. Chadwick along with the Cryptozoic eon.

PALEOZOIC ERATEMA(ERA) (Paleozoic) (from paleo... and Greek zoe - life) Beginning 570 ± 20 million years ago, duration 340 ± 5 million years. Includes 6 geological systems. It is characterized by 2 main epochs of folding: Caledonian (Great Britain, Scandinavian Peninsula, Svalbard, Kazakhstan, etc.) and Hercynian (Central Europe, Urals, Appalachians). At the beginning of the Paleozoic erathem, there was a rapid spread of organisms with a hard skeleton that had not been encountered before (chiolites, gastropods, brachiopods, archaeocyates, trilobites, etc.). From vertebrates, fish, amphibians, and reptiles appear. The flora at the beginning of the Paleozoic erathem was represented mainly by algae, psilophytes and later by club mosses, arthropods, etc. Of the minerals, the main role is played by coal, oil, oil shale, phosphorites, salts, cuprous sandstones, etc.

Early Paleozoic stage (Cambrian, Ordovician, Silurian) - Caledonian folding, as a result of which mountain structures arose in most of the British Isles, the northwestern part of Scandinavia, the western part of the Center. Kazakhstan and others. The climate is characterized by the predominance of warm conditions. The exit of living organisms to land is constrained by a lack of oxygen in the atmosphere (1/3 of the current amount)

THE CAMBRIAN SYSTEM (PERIOD) (from Cambria, Cambria - the Latin name for Wales) The Cambrian period began 570 million years ago, lasting 80 million years. Marine sediments of the Lower Cambrian are widespread - the result of extensive transgressions of the sea; in the Middle Cambrian until the beginning of the Late Cambrian regression occurred in many places. In the Upper Cambrian, lagoonal red-colored rocks were first established. The main tectonic structures were formed at the end of the Riphean.

In the Cambrian period, skeletal organisms appeared for the first time in geological history. The Early Cambrian is characterized by trilobites and archaeocyates; there were brachiopods, molluscs, sponges, coelenterates, worms, ostracods, echinoderms; at the end of the Cambrian period, tabulates and graptolites, as well as trilobites, are common. The flora is represented by blue-green and red algae and primitive higher plants. Of the minerals of the Cambrian period, phosphorite deposits are significant in Kazakhstan, Mongolia, China, etc.

ORDOVICAN SYSTEM Beginning of the Ordovician period 490 ± 15 million years ago, duration 65 million years. In the early and early Middle Ordovician - the maximum expansion of marine spaces. As a result of the manifestation of the Taconian phase of the Caledonian folding at the end of the Ordovician period, mountain structures of Kazakhstan, Scotland, etc. were formed.

Representatives of almost all types of invertebrates (radiolarians, foraminifers, graptolites (primitive hemichordates), trilobites, etc.) existed in the water bodies of the Ordovician period, the first vertebrates appeared - jawless fish-like ones; dominated by bacteria, various algae, psilophytes. In the deposits of the Ordovician period, the most significant are oil shale (Baltic), phosphorites, iron and manganese ores.

SILURIAN SYSTEM. Started 435 million years ago, duration 30 million years. It is divided into 2 departments. The largest landmass in the Silurian system is the mainland Gondwana. The beginning of the Silurian period was characterized by global marine transgression, the end - by the completion of the Caledonian folding.

In the Silurian, all the main classes of invertebrate organisms were formed, the first primitive vertebrates (jawless and fish) appeared, the first terrestrial flora - psilophytes. By the end of the period, the number of trilobites is greatly reduced (they ate nautiloids). Main minerals: copper pyrite ores, phosphorites, manganese and iron ores, gypsum and salt.

Late Paleozoic stage (Devonian, Carboniferous, Permian) Hercynian folding. As a result of the Hercynian folding, folded structures of the Zap. Europe (the so-called Hercynian Europe), the Urals, Tien Shan, Altai, Kunlun, and others, the climate becomes drier and more continental.

Some representatives of animals are dying out (trilobites, graptolites), others are sharply reducing their living space and numbers (echinoderms, nautiloids, corals), completely new representatives appear to replace them. The flowering of brachiopods, ammonites. Widespread fish, crustacean scorpions (lagoons). The first animals come to land. Algae (blue-green, red, characeae) dominate in the ocean, and higher plants (psilophytes, club mosses, horsetails, ferns) dominate on land.

DEVONIAN SYSTEM. It began 400 million years ago and lasted about 55 million years. It is subdivided into 3 departments and 7 tiers. The beginning of the period was characterized by the retreat of the sea and the accumulation of thicknesses of thick continental (red-colored) deposits in connection with the completion of the Caledonian folding; The climate is continental, arid. The middle of the period is the era of immersions; increase in marine transgressions, intensification of volcanic activity; climate warming. The end of the period is the reduction of transgressions due to the beginning of the Hercynian folding.

Armored and lobe-finned fishes developed in the seas (in the late Devonian, stegocephals originated from them), ammonites, foraminifers, brachiopods (brachiopods), ostracods, and corals appeared; on land - at the end, mites and spiders appear, the first great-ferns (Archaeopteris flora), pragymnosperms, articular-stem. Plants have a skin with stomata, the body differentiates into a stem, roots, leaves) The main minerals are oil and gas, rock and potassium salts, cuprous sandstones.

COAL SYSTEM. Began 345 million years ago; duration 65 million years. Subdivided into 3 or 2 sections. At the beginning of the period, the sea flooded a significant part of the continents; at the end, a significant glaciation occurred in the Southern Hemisphere. In the Carboniferous period, intense tectonic movements took place - the Hercynian folding.

The land was settled by the first terrestrial vertebrates - stegocephals, large insects, cotylosaurs appeared; among the plants, tree-like ferns, club mosses (lepidodendrons, sigillaria, calamites) prevailed, the first conifers appeared. On the coastal plains deposits of peat and coal were formed. In the marine fauna, the flowering of four-rayed corals, large rhizopods (fusunilids - up to 1-2 cm, foraminifera order), bryozoans, various mollusks and ancient fish (selachia). During the Carboniferous period, the largest coal basins of the world were formed: Donetsk (Ukraine), Kuznetsk, Tunguska (Russian Federation), Appalachian (USA), Ruhr (Germany), etc.

PERM SYSTEM. Started 280±10 million years ago, duration 45 million years. The Permian system was identified in 1841 by the English geologist R. Murchison in the Urals and the Russian Plain (on the territory of the former Perm Province, hence the name). It is divided into lower and upper sections. The Permian period was characterized by intense tectonic movements associated with the last phases of the Hercynian folding and extensive sea regressions. Within the boundaries of modern continents, continental conditions prevailed, in which coal-bearing, salt-bearing and red-colored deposits were formed.

Among the terrestrial plants, arthropod ferns and gymnosperms predominated; among animals - amphibians, primitive reptiles, insects, foraminifers, corals (rugoses), bivalves, gastropods and cephalopods, bryozoans, brachiopods, marine arthropods, sea lilies lived in the seas; from vertebrates - cartilaginous shark-like fish. The sediments of the Permian system contain coal, oil and gas, rock and potassium salts, cuprous sandstones, and phosphorites.

MESOZOIC ERATEM(ERA) (Mesozoic) (from Meso... and Greek zoe - life). Beginning 235 million years ago, duration about 170 million years. It is divided into 3 systems (periods): Triassic, Jurassic and Cretaceous. There is an intense manifestation of folding, mountain building and magmatism. Laurasia and Gondwana break apart - the formation of modern continents. Characteristic is the dominance of reptiles (dinosaurs, ichthyosaurs, pterosaurs, etc.), sometimes reaching enormous sizes. Numerous insects, birds, and mammals appeared. The invertebrates were dominated by ammonites and belemnites, which became extinct by the end of the era. The flora is renewed, the ginkgo and cycads flourish, peat deposits are formed.

TRIASIC SYSTEM (from the Greek trias - trinity) It began 235 ± 10 million years ago, the duration was 50 million years. It is divided into 3 departments. The renewal of marine and terrestrial fauna is characteristic. In the seas, ammonoids (ceratites), pelecypods, and gastropods played the main role among invertebrates; belemnites, bony fishes, appeared for the first time, the number of cartilaginous fishes is declining. The flourishing of reptiles - large reptiles (dinosaurs) is characteristic, the first mammals appeared (oviparous and marsupials). The flora was dominated by ferns, cycadophytes, ginkgoes and conifers. The main minerals of the Triassic period are coals, oil, diamonds, uranium, copper-nickel ores.

JURASSIC SYSTEM Beginning 185 ± 5 million years ago, duration 53 million years. It is divided into 3 departments. In the early Jurassic, a significant renewal of the composition of ammonites took place in the marine basin, belemnites reached their peak; Sponges and colonial corals (reef structures) are common. Developed fish. Among the terrestrial fauna, flying lizards (rhamphorhynchus, pterodactyls, pteranodons) and birds appeared. Individual representatives of reptiles have reached enormous sizes. Mammals are few and primitive. The terrestrial vegetation is dominated by gymnosperms: ginkgos, cycads, bennettites, and conifers; there are many ferns, horsetails, etc. Of the minerals, the most significant are deposits of oil and gas, coal, oolitic iron ores, phosphorites, etc.

CHALKET SYSTEM. Beginning 132-137 million years ago, duration 66 million years. Wide development and then extinction of the last ammonites and belemnites, many species of large reptiles; common toothy birds, the first placental mammals, bony fish, large reptiles. Ferns and gymnosperms are typical among plants; angiosperms appear in the second half of the Cretaceous. The sediments of the Cretaceous period are represented by deposits of writing chalk, oil, sedimentary iron ores, etc.

Cenozoic erathema(ERA) (Cenozoic) (from Greek kainos - new and zoe - life). Beginning 66 million years ago. It is subdivided into Paleogene, Neogene and Quaternary (Anthropogenic) systems (periods). It is characterized by intense mountain-building movements associated with Alpine folding and created the highest mountain ranges on the periphery of the Pacific Ocean, in southern Europe and in Asia; at the end of the Neogene - the beginning of the Anthropogenic time, a sharp change in climate occurred, accompanied by a powerful continental glaciation that covered vast areas in Eurasia and the North. America.

In the organic world, the dominant position is occupied by mammals; animals and plants are close to modern. At the beginning of the Anthropogen, the first primitive people appear.

PALEOGENIC SYSTEM (from paleo... and Greek genos - birth, age). Beginning 66 ± 3 million years ago, duration 41 million years. It is divided into 3 divisions: Paleocene, Eocene and Oligocene. In the Paleogene period, large tectonic movements took place with the formation of mountain structures (Cordillera, Andes). Maximum transgression at the end of the Eocene. The climate is uniformly warm.

By the beginning of the Paleogene period, mammals (primitive placental, cloacal, marsupials) were widely developed, insects, rodents, primates, etc. appeared; many groups of reptiles died out, amphibians and bony fish existed. Of marine organisms, foraminifera, nannoplankton, radiolarians, diatoms, etc. are of great importance for the correlation of strata. In the plant world, angiosperms and gymnosperms predominated. The deposits of the Paleogene period are rich in brown coal, oil and gas, phosphorites, bauxites, potassium salts, iron and manganese ores, etc.

NEOGENE SYSTEM (from neo... and Greek genos - birth, age). Beginning 23.5-25 million years ago, duration 22-23 million years. It is divided into 2 divisions: Miocene and Pliocene. During the Neogene period, as a result of Alpine folding, the mountains of the Caucasus, the Alps, and the Himalayas were formed.

In the Neogene system, flora and fauna become close to modern ones. The rise of placental mammals (carnivores, herbivores, primates). Appearance of the great apes. The Neogene system is rich in deposits of oil, gas, brown coal, salts, bauxites.

QUATERNARY SYSTEM, Anthropogenic system (period). The duration is estimated from 700 thousand years to 2.5-3.5 million years. It is divided into Pleistocene and Holocene. When dismembering the system, mainly bio- and climatostratigraphic methods are used. During the Quaternary period, the relief, climate, vegetation and fauna took on a modern look; the development of glaciations is characteristic (especially in the Northern Hemisphere). The formation of man is connected with the Quaternary period.

PLEISTOCENE (from the Greek pleistos - the largest and kainos - new), the lower section, corresponding to the longest era of the Quaternary period. It is characterized by a general cooling of the Earth's climate and the periodic occurrence of extensive continental glaciations in the middle latitudes.

HOLOCENE (from the Greek holos - whole, complete and kainos - new) (post-glacial epoch), the modern geological epoch, which is the last, unfinished segment of the Quaternary (Anthropogenic) period of geological history, and the corresponding deposits. The beginning of the Holocene coincides with the end of the last continental glaciation in northern Europe.