What civilizations existed on earth before people? History of the development of planet earth A mysterious find is direct evidence of the existence of an “elder race”
On Earth, even before the appearance of man, events took place over millions of years that changed our planet. The seas repeatedly attacked the land, eroding and destroying it; Mountain ranges rose from the waters of the sea. They, in turn, were washed away by rain and snow waters, rivers cutting into their slopes, and worn away by glaciers descending from mountain peaks. At the bottom of the seas, on islands and continents, volcanoes erupted molten lava, covering vast areas and changing the face of the Earth beyond recognition. Winds in the deserts scattered mountain ranges into dust, transported and deposited powerful layers of sand that accumulated over vast areas of our planet. But how could a person find out what was happening on Earth before his appearance?
All the changes that the globe has undergone since the formation of the earth’s crust on it to the present day are studied by historical geology. She finds out where in the past there were seas and where there was land, where volcanic eruptions occurred, where mountains rose. Historical geology establishes not only the events that took place many millions of years ago on Earth, but also their sequence: what happened before and what happened later. Rocks as monuments of past events Observing the surrounding nature, man noticed that every event occurring on Earth leaves a trace, a memory of itself in the form of certain mineral accumulations that turn into rocks.
On land, thanks to the work of rain and flowing waters, clay-sand sediments containing small pebbles, and often shells of freshwater mollusks, accumulate. Winds in deserts, destroying mountain ranges, contribute to the accumulation of thick layers of dune sands, different in composition from sands washed by water. In salty lakes, in dry and hot climates, rock salt accumulates; in the seas off the coast, pebbles and sand accumulate, and further, in the open sea, calcareous and clayey sediments, which subsequently turn into limestones and shales.
Each volcanic eruption produces a huge amount of mineral material. Volcanic ash, compacting and caking, turns into volcanic tuff; When lavas solidify, they form various volcanic rocks: basalt, obsidian (volcanic glass), etc. Thus, each rock arose as a result of certain events that took place on Earth. The characteristics of rocks, their mineralogical composition, structure, and nature of occurrence provide geologists with material to determine the conditions under which rocks were formed. Observing the changes taking place on the Earth in our time and studying how various sediments are formed, we can conclude that in the distant past our Earth changed in general under the influence of the same processes that are occurring now.
But in different places on the globe these processes proceeded differently. Near Moscow in ravines, on the slopes of river valleys, 
directly under the soil one can observe thicknesses of peculiar red-brown coarse loams with many rounded stones - boulders of various sizes and composition. The boulders consist of crystalline rocks: granites, gneisses, quartzites, etc. These rocks are not found in bedrock near Moscow, but are widespread in Finland, on the Kola Peninsula. Scientists have found that boulders and ancient boulder loams are deposits of a huge glacier that once advanced onto the Russian Plain from Finland. Destroying and abrading rocks made of granites, gneisses and other crystalline rocks, the glacier took fragments with it and dragged them many kilometers to the south. Melting and gradually disappearing, the glacier deposited these worn-out fragments along with clayey and sandy sediments in the form of boulder loams - moraines. Where the edge of the glacier was located for a long time, entire banks of terminal moraines accumulated.
Many of us watched Jurassic Park and admired the gigantic monsters recreated by technology. However, our knowledge of dinosaurs is often limited to what is presented in this nostalgic film. We publish 13 facts that will surprise you.
Walt Disney insisted on an anatomically incorrect depiction of the T-Rex
In the 1940 cartoon Fantasia, the Tyrannosaurus rex is depicted with three toes on its forelimbs. In fact, tyrannosaurs only have two fingers. The famous cartoonist added one more, as it looks scarier and more familiar to the human eye.
Dinosaurs ruled the Earth for 160 million years
Reptiles lived on Earth before dinosaurs appeared. About 300 million years ago, global warming occurred, which caused an evolutionary explosion among reptiles. The first dinosaurs appeared on Earth during the Mesozoic era about 230 million years ago, and the mass extinction of these giant reptiles occurred 65 million years ago. For comparison, the oldest remains of Homo sapiens are only 200 thousand years old.
The extinction of the dinosaurs was not instantaneous
Experts believe that dinosaurs were already on the verge of extinction when the asteroid hit Earth. According to the biosphere hypothesis, the extinction of dinosaurs predetermined the emergence of flowering plants, which significantly changed food chains in ecosystems and gradual climate change caused by continental drift.
41% of Americans believe that dinosaurs and humans existed in the same era
41% of American adults believe that dinosaurs and humans lived side by side. Of course this is not true. But next to humans on Earth live birds, which are direct descendants of dinosaurs. Most researchers are inclined to believe that birds descended from theropod dinosaurs from the group of maniraptors.
The word "dinosaur" appeared in the 19th century
In 1824, the president of the Royal Geological Society, William Buckland, gave a report on the discovery made in 1815 in Great Britain. These were several giant bones. Buckland classified the find as the remains of a giant predatory lizard and called it a megalosaurus - "a huge lizard." In the two decades following Buckland's report, biologists found other remains of colossal size. In 1842, the English biologist Richard Owen noted the similarities between the described new species of lizards and their differences from modern reptiles. He separated these into a special suborder, calling it Dinosauria (Latin for “terrible lizard”).
Velociraptors in Jurassic Park are Wrong
Velociraptors in the film “Jurassic Park” are huge bloodthirsty lizards that hunted in packs and most often attacked people. In fact, velociraptors were only 50 -80 cm tall and never hunted in packs. But the closest relatives of these dinosaurs, Deinonychus, were twice the size of velociraptors and often gathered in groups to hunt. The film's scriptwriter, Michael Crichton, based his writing on the reconstruction of Deinonychus.
Dilophosaurus did not spit venom
Another mistake in Jurassic Park: screenwriter Michael Crichton explained the weakness of the Dilophosaurus's jaws by saying that it hunted by hitting its prey with poisonous saliva sprayed over a long distance. This was done solely for dramatic effect: the Dilophosaurus was not at all poisonous.
T-Rex was a scavenger
Many people are accustomed to thinking that Tyrannosaurus is the most bloodthirsty hunter of the Jurassic period. However, scientists have long debated its diet. Some paleontologists have defended the idea that the royal T-Rex was actually a scavenger, since, in their opinion, its teeth were not adapted for hunting. However, scientists have now concluded that tyrannosaurs could feed on both fresh meat and carrion at the same time. Younger dinosaurs had to hunt for food, and older dinosaurs took prey from the young.
Some lizards weighed 60 tons
The largest dinosaur is considered to be Dreadnoughtus from the genus of titanosaurs. Its length was about 26 meters and its weight was 59.3 tons. This is equivalent to the weight of a dozen African elephants or seven T-Rexes. The giant lizard was named after the largest warships of the early twentieth century. This dinosaur was discovered in 2014. It is assumed that the discovered Dreadnoughtus died when an ancient river flooded: under the weight of the animal, the soil turned into a kind of quicksand and absorbed the colossal reptile.
The brain of a stegosaurus is very light
It is widely believed that the brain of Stegosaurus was the size of a walnut. Indeed, in 2013, paleontologist Lawrence Witmer said in a Facebook post that he and his colleagues had come up with a new unit for measuring dinosaur brains—the walnut—and it was misunderstood in the press. What the scientist actually meant was that the brain of a stegosaurus (which is actually the size of a dog) looks like a walnut on the scale of these animals. Indeed, it is very light: 70 grams per 2 tons of live weight. However, in the spinal canal of the stegosaurus there is an expansion filled with nervous tissue. Scientists called it the dinosaur's "second brain." It is now believed that this expansion is responsible for supplying the nervous system with glycogen.
Sauropods swallowed rocks
It is known that sauropods (herbivorous dinosaurs, including brachiosaurs and diplodocus) swallowed small pebbles to improve digestion. Birds and crocodiles inherited this tradition from their distant ancestors.
Dinosaur eggs aren't always white
Dinosaur eggs are usually white. However, in 2015, scientists discovered pigments that colored the shell blue and green. The pigments biliverdin and protoporphyrin are found in the eggs of some ancient orders of birds. The eggs of the dinosaur species Heyuannia huangi had a camouflage color similar to the color of the eggs of modern emu ostriches.
Soft tissue can last for millions of years
In 1981, amateur paleontologists discovered the remains of a dinosaur that was later named Scipionyx samniticus (Scipio's claw). The find became famous because of the unique preservation of the fossilized soft tissue and internal organs such as muscle and intestine, as well as the internal structure of some muscle and bone cells.
The science
Life existed before the appearance of the Earth and, perhaps, was outside the solar system, say scientists.
Two geneticists applied knowledge of computer science and biology and came to the conclusion that organic life first appeared long before our planet.
Alexey Sharov from the National Institute on Aging in Baltimore, USA and theoretical biologist Richard Gordon applied Moore's scientific law to make a mathematical calculation.
Moore's Law states that the complexity of computers increases exponentially, meaning the number of transistors on a chip doubles every 2 years. Geneticists replaced transistors with nucleotides - the building blocks of DNA and RNA and calculated when life arose on Earth
The results showed that life appeared about 10 billion years ago, much earlier than the estimated age of the Earth - 4.5 billion years ago.
How is this possible? Scientists explained that when our solar system was formed, organisms similar to bacteria or simple nucleotides from older parts of the galaxy fell to Earth along with comets, asteroids and other inorganic space debris.
In science, this process is called panspermia.
While many may be skeptical of this idea, scientists believe that contamination by bacterial spores from space is the most plausible hypothesis for the emergence of life on Earth.
“We are 99 percent sure that life appeared before the Earth, 1 percent remains for some ridiculous accident that we did not take into account,” Sharov explained.
The emergence of life on Earth
How did life originate on earth? There are several theories about this.
Development of life on Earth
The Earth has existed for just over 4.5 billion years. The beginning was quite brutal, with meteorites constantly falling on the Earth. When this period ended, the Earth cooled and a crust formed on its surface.
There were no continents as such - only the world ocean with small islands. Erosion, sedimentation, and volcanic activity eventually created small primordial continents that grew until they reached their present size 2.5 billion years ago.
Throughout history, the earth has undergone many geological and biological changes.
Brief stages of life on Earth:
- 3.8 billion years ago the first form of life appeared - prokaryotes
- 2.1 billion years ago multicellular life forms appeared
- 1.5 billion years ago eukaryotes appeared - cells containing a nucleus
- 200 million years ago a view appeared Homo Sapiens(reasonable person)
And would it be the same as it is today if we did not exist at all?
Imagine for a moment that the last 125 thousand years of Earth's history were recorded somewhere on film - a thin, old-fashioned tape tucked between two metal reels. Every second, a certain amount of film is unwound from one cassette and wound onto another. Now imagine that it is possible to stop the film, intervene in this process and change the direction of movement. Let's rewind.
Gradually, with each new turn of the reel, our current reality is removed. Every minute, an area of natural forests and wooded areas the size of 10 football fields is restored. Every year, an area slightly larger than Denmark becomes forested again. It only takes 150 years to rewind in order for everything that was lost to be restored. At the same time, clusters of cities recede like the ebb of a concrete mass. Mega-cities shrink to the size of regular cities, then shrink to the size of villages and villages, and then green swaths of untouched and uncultivated land reappear. Existing rivers are freed from dams. The ozone layer is being restored. The remains of the planet's estimated 108 billion people are being removed from the earth, and fossil fuels, gems and metals, and other mined minerals are being returned to their original place. Tons of planet-polluting debris, including sulfur dioxide and carbon dioxide, are being sucked out of the atmosphere.
Finally, we find ourselves at a point that seems unimaginably far from us - 125 thousand years ago. In geological terms, it may feel like yesterday, but the length of time between then and now represents the entirety of human existence on the planet. By rewinding the film to this point, we have eliminated virtually all traces of human impact on the Earth. And what happened?
125 thousand years ago, the Earth was in the middle of the Eemian interglacial period, which lasted 15 thousand years and represented a temperature phase between longer and colder ice ages. Suddenly the whole world became warm and green. In the northern hemisphere, continental snow cover has retreated south almost to the level of Germany in Europe and Illinois in North America.
“It was a little warmer then than it is today, and sea levels were probably a little higher and at their highest,” said Ian Tattersall, curator of anthropology at the American Museum of Natural History in New York City. American Museum of Natural History).
One of the beneficiaries of such warming was Homo sapiens- a reasonable person. Our species first appeared approximately 200 thousand years ago in eastern Africa; 125 thousand years ago the population of this species was probably somewhere between 10-100 thousand individuals. They obtained food for themselves, hunted and made their first raids, leaving the homes of their ancestors.
However, we were not alone. “There were at least three lineages of hominids at that time,” says Tattersall, an expert on early human evolution. — Homo sapiens existed in Africa ( Homo sapiens); Homo erectus settled in the eastern part of Asia ( Homo erectus), which subsequently became extinct; and Neanderthals lived in Europe.”
Other members of the human race, both unknown and partially known to us, struggled to survive in other parts of the planet. “Nobody knows what happened in Africa,” says Tattersall. “There were hominids in Africa that looked completely different from modern Homo sapiens.”
Large animals also existed in abundance in the world - whales in the ocean and giant herds of herbivores on land. “I think if it were possible to teleport to that world, you would immediately notice the megafauna,” says environmental historian Jed Kaplan of the interdisciplinary department of environmental studies at the University of Geneva in Switzerland. of Geneva "s Institute for Environmental Sciences). - You would find huge herds of animals moving around the world. There would be woolly mammoths that inhabited the Arctic. And you would undoubtedly be able to see bison. In Europe you would find large cats, and in America there would probably be many horses, and also a large number of bears, wolves, and also many herd animals.”
Going beyond nature
But then, without any warning, everything changed. Or, to be precise, first human beings changed, and then the same thing happened to the world around them. “Something terrible happened at the very moment when people began to behave in modern ways, and this began 100 thousand years ago,” Tattersall notes. “And it was at that time that human beings, in a certain sense, went beyond the boundaries of nature, found themselves in opposition to it and began to do all the stupid things that we are very familiar with today.”
Reading through the list of nonsense that Tattersall talks about is sobering. Just 2 thousand years before the birth of Christ, the world population was several tens of millions. In 1700 after the Birth of Christ, there were already 600 million people on the planet; and today their number slightly exceeds 7 billion and continues to increase, according to experts, by 220 thousand people per day. And those are just human beings. According to the FAO, the global cattle population is 1.4 billion, and in addition, at any given time there are approximately a billion more pigs and sheep, as well as 19 billion chickens, or almost three for every person.
According to the data we have, we are using more energy today than ever before. In the 20th century alone, its consumption increased 16 times. According to information published in 2009 in the International Journal of Oil, Gas and Coal Technology, approximately 944 billion barrels of oil - or 135 billion tons - have been extracted from the Earth's interior since 1870. In 2011 alone, the United States produced more than a billion tons of coal, and China produced 3 times that amount.
We also radically changed the landscape. Agriculture, coupled with the use of fire, has subjugated the environment almost everywhere and reshaped it. In many regions, cultivated land has replaced natural vegetation. Between 30% and 50% of the earth's surface is currently used in one way or another for human benefit, and we consume more than half of the available fresh water supplies.
Especially rice production has flattened all ecosystems. “People are creating small dams,” says Earl Ellis, an environmental scientist at the University of Maryland. “And that changes the whole movement of sediment in the river basins.” The goal is to create wetlands in many places suitable for rice cultivation. As a result, a large number of areas became flatter. It makes an impression."
There are very few places left in the modern world that look the way they would if there was no human intervention at all. “There are very few landscapes left untouched, especially in Europe,” Kaplan points out. “There are practically no forests left where you could see large dead trees just lying on the ground. This is incredibly rare."
Just from the moment when man began to oppose himself to the still preserved nature, people spread throughout the world, like seeds driven by gusts of wind, and as a result, about 125 thousand years ago they settled in the Middle East, 50 thousand years ago - in South Asia , 43 thousand years ago - in Europe, 40 thousand years ago - in Australia and in both Americas in the period from 30 thousand to 15 thousand years ago. The last intensively populated territory was New Zealand, and this happened about 700 years ago.
Wherever people went, they brought animals with them - some deliberately (dogs, cats, pigs), and others by accident (rats). Introducing alien species into a delicately balanced ecosystem can have serious and irreversible consequences, Ellis argues, especially for rats: “Their impact on the ecosystem is very large. All living creatures that create nests for themselves on the ground or in any other place accessible to rats are doomed.”
Of course, we ourselves are effective killers. As you know, many species of animals have been exterminated by hunting or persecution, and the most famous example in this regard is the dodo (their last confirmed sighting was recorded in 1662). Also extinct: Steller's sea cow (1768), nilgai (ca. 1800), Mauritian blue pigeon (1826), great auk (1852), sea mink (ca. 1860), Falkland wolf (1876), passenger pigeon (1914), and also Caribbean monk seal (1952). Many other species have also disappeared within our memory. Human beings march across the planet, and behind them, one after another, waves roll in, destroying the megafauna. The reasons for this are still debated, but many point the finger at us. “I actually believe that human beings have contributed to the extinction of numerous megafaunal species,” Kaplan notes.
For example, 15 thousand years ago, human beings penetrated through Siberia to North America. “This is an unprecedented period of extermination,” said Bill Ruddiman, a climate scientist at the University of Virginia. “This required the emergence of something completely new, and this new thing turned out to be human beings.”
“The American West, the plains there, had a diversity that was much richer than what is today Serengeti National Park,” Ruddiman notes. — It was an amazing place. In addition to mammoths and mastodons, there were saber-toothed tigers, horses, camels, and giant ground sloths - all of these species became extinct within a fairly short period of time. The most reliable evidence suggests that this happened approximately 15 thousand years ago.”
Today, the wide—and mostly empty—spaces of the American West have changed dramatically from what they looked like 125,000 years ago.
The destruction of large animals by humans has had an impact on the landscape, which is noticeable almost everywhere. “Vast spaces used to remain semi-open, they became so as a result of the presence of large numbers of grazing animals, feeding on grass and branches, as well as predators,” Kaplan notes. — It is important to remember that landscapes are also shaped by animals. Huge herds of bison trampled small trees and thus left the space open - of course, not to the same extent as man who used fire, but this influence was undoubtedly noticeable.
water world
In addition, we have devastated the oceans. According to a study published in 2010, the UK fishing fleet must work 17 times harder today than in the 1880s to catch the same amount of fish. FAO estimates that more than half of the world's coastal fisheries are overfished.
Whale hunting has also changed the oceans beyond recognition. During the 20th century, some whale species were on the verge of extinction, and their populations have not yet been restored. A controversial study published in the journal Science claims that the whale population was significantly larger before the hunt began than previously thought. According to this study, there were once 1.5 million humpback whales in the world, not 100 thousand, as experts from the International Whaling Commission believe. The same can be said about minke whales, polar whales and sperm whales.
We have also changed the climate. In May of this year, the content of carbon dioxide in the atmosphere exceeded 400 ppm for the first time in millions of years; 125 thousand years ago its content was 275 ppm. This increase is partly due to the use of fossil fuels, but also to the decline of forests, which for millions of years acted as a virtually bottomless carbon sink.
This impact left a noticeable imprint on the ice on our planet. All over the world, glaciers began to shrink, and in some places they disappeared altogether. The US National Snow and Ice Data Center, organized at the University of Colorado in Boulder, monitors approximately 130 thousand glaciers around the world. Some of them are increasing, but many more are decreasing. In general, we can say that for every glacier increasing in size, there are at least 10 shrinking ones. When it was created in 1910, Glacier National Park in Montana contained 150 glaciers. Today their number does not exceed 30, and all of them have shrunk in size. In 2009, the Chacaltaya glacier in Bolivia disappeared, and at one time it was the highest place in the world with ski lifts. The ice cover in the polar latitudes is destroyed, and ice floes the size of cities break off from it. In July this year, a 30-kilometer crack in the Pine Island glacier in Antarctica resulted in the formation of an iceberg the size of New York City.
As a result of rewinding the time tape, all traces of human influence on planet Earth disappear. Now, just for fun, let's play another game - remove Homo sapiens altogether. Imagine if, 125,000 years ago, a small number of our ancestors in eastern Africa were wiped out by some catastrophe—a deadly virus or perhaps a natural disaster. And now let's fast forward the tape. What would our planet look like today if there were no modern human beings on it?
In some ways, the answer seems obvious: it would have looked much the same as it did 125,000 years ago. “We would have a continuously existing biosphere, and it would be something that is even difficult for us to imagine. That is, there would be forests, savannas and the like - and so on across the entire surface of the planet, says Jan Zalasiewicz, a geologist at the University of Leicester in the United Kingdom. - No roads, no fields. No cities. Nothing like that." Large animals would exist in abundance on Earth, and there would be many whales and fish in the seas.
However, this could not continue for long, says Ruddiman. If human beings had gone extinct 125,000 years ago, we would be entering a new ice age today. Glaciers would increase in size and move forward. This in itself is a controversial idea, and one for which Ruddiman has been criticized. Today, however, ten years after he first expressed it, many climate scientists agree with him.
“If you take away human influence, there will be significantly more ice in the seas, and the tundra in the Arctic Circle will also increase in area,” he notes. “The boreal forests would recede and, most importantly, ice cover would increase in many northern regions—the northern Rocky Mountains, the Canadian Arctic Archipelago, parts of northern Siberia.” These are the earliest stages of the onset of the Ice Age. And that’s the single most significant change.”
Or maybe everything would have turned out differently. It is possible that our place could be taken by another human species, for example, Neanderthals, Homo erectus, or some hitherto unknown species, and it would begin to determine everything that happens on the planet instead of us.
Tattersall has doubts. “Having established themselves on Earth, would they follow our example? he asks. “Would they be a substitute for Homo sapiens, which would suggest that there is a certain kind of inevitability about what happened to us?” I think it’s unlikely.”
However, there is a great counter-argument to this.
“There's also this concept called convergent evolution, which is that if we hadn't come along and done it, someone else would have,” says David Grinspoon, the museum's curator of astrobiology. of Nature and Science in Denver, Colorado. “In that case, there would be selective pressure on other species, which would push them towards the same development path that we have taken, where there is feedback between a large brain, language and abstract thinking, as well as the development of agriculture.” If the scenario was literally that Homo sapiens goes extinct and the overall landscape remains, then perhaps something similar would happen. It wouldn't be exactly the same because there's a lot of randomness, and it would probably take longer."
In short, all this would have happened anyway. Perhaps the formation of the modern version of the Earth and our place on it was inevitable. Remove Homo sapiens from this equation, restore forests and megafauna, and then, maybe in 100 thousand years, we will again get the same result - our greatest works, our achievements and our mistakes. Or at least something similar.
“I would love to have a magic crystal or some version of an alternate world viewfinder,” Grinspoon admits. “It would be great to know.”
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.
Our planet is believed to be about 4.54 billion years old. This entire time period is usually divided into two main stages: Phanerozoic and Precambrian. These stages are called eons or eonothema. Eons, in turn, are divided into several periods, each of which is distinguished by a set of changes that occurred in the geological, biological, and atmospheric state of the planet.
- Precambrian, or cryptozoic is an eon (time period in 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 eonothems - catarchaean and archaean. The latter, in turn, includes 4 eras.
1. Katarhey- this is the time of the formation of the Earth, but there was no core or crust yet. The planet was still a cold cosmic body. Scientists suggest that during this period there was already water on Earth. The Catarchaean 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, and deposits of sulfur, iron, graphite, and nickel were being formed. The hydrosphere and atmosphere were a single vapor-gas shell that enveloped the globe in a dense cloud. The sun's rays practically did not penetrate through this curtain, so darkness reigned on the planet. 2.1 2.1. Eoarchaean- This is the first geological era, which lasted about 400 million years. The most important event of the Eoarchean was 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, the 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, formed.
2.2 Paleoarchean- the next era, which also lasted approximately 400 million years. During this period, the Earth's core is formed and the magnetic field strength increases. A day on the planet lasted only 15 hours. But the oxygen content in the atmosphere increases due to the activity of emerging bacteria. Remains of these first forms of Paleoarchean life have been found in Western Australia.
2.3 Mesoarchean also lasted about 400 million years. During the Mesoarchean era, our planet was covered by a shallow ocean. The 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 first formed on Earth. Biological species are still represented by bacteria and microbial life forms.
2.4 Neoarchaean- 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 was 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 appears for the first time, and the world ocean reaches almost its modern volume. And after the long Huronian 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 previous forms of life practically died out due to an increase in oxygen content. This period was called the oxygen catastrophe. By the end of the era, the first eukaryotes appear on Earth.
3.2 Meso-Proterozoic 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 approximately 8 parts, the superocean 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. Climatic zones begin to form, and the flora and fauna are represented mainly by marine species. Only towards the end of the Paleozoic did land development begin and the first vertebrates appeared.
The Paleozoic era is conventionally divided into 6 periods.
1. Cambrian period lasted 56 million years. During this period, the main rocks are formed, and a mineral skeleton appears in living organisms. And the most important event of the Cambrian is the emergence 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 bony fishes in the history of the planet appear. On land, the Silurian is marked by the appearance of vascular plants. Supercontinents are moving closer together and forming Laurasia. By the end of the period, ice melted, sea levels rose, and the climate became milder.
4. Devonian period is characterized by the rapid development of diverse life forms and the development of new ecological niches. The Devonian covers a time period of 60 million years. The first terrestrial vertebrates, spiders, and insects appear. Sushi animals develop lungs. Although, fish still predominate. The flora kingdom of this period is represented by propferns, horsetails, mosses and gosperms.
5. Carboniferous period often called carbon. At this time, Laurasia collides with Gondwana and a new supercontinent Pangea appears. A new ocean is also formed - Tethys. This is the time of the appearance of the first amphibians and reptiles.
6. Permian period- the last period of the Paleozoic, ending 252 million years ago. It is believed that at this time a large asteroid fell on 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, and the most extensive deserts appear that have ever existed in the entire history of the development of the Earth.
IV. Mesozoic- the second era of the Phanerozoic eon, which lasted almost 186 million years. At this time, the continents acquired almost modern outlines. A warm climate contributes to the rapid development of life on Earth. Giant ferns disappear and are replaced by angiosperms. 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 just over 50 million years. At this time, Pangea begins to break apart, and the internal seas gradually become smaller and dry out. The climate is mild, the zones are not clearly defined. Almost half of the land's plants are disappearing as deserts spread. And in the kingdom of fauna the first warm-blooded and land reptiles appeared, which became the ancestors of dinosaurs and birds.
2. Jurassic covers a span of 56 million years. The Earth had a humid and warm climate. The land is covered with thickets of ferns, pines, palms, and cypresses. Dinosaurs reign on the planet, and numerous mammals were still distinguished by their small stature and thick hair.
3. Cretaceous period- the longest period of the Mesozoic, lasting almost 79 million years. The separation of the continents is almost ending, 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 the greenhouse effect. At the end of the Cretaceous period, 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. At this time, the continents acquired their modern shape, Antarctica occupied the south pole of the Earth, and the oceans continued to expand. Plants and animals that survived the disaster of the Cretaceous period found themselves in a completely new world. Unique communities of life forms 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 this time, a tropical climate reigned on Earth, Europe was hidden under evergreen tropical forests, only deciduous trees grew in the north of the continents. It was during the Paleogene period that mammals developed rapidly.
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 emergence 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.
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