An interesting service has appeared on the global network (dinosaurpictures.org), which allows you to see what our planet looked like 100, 200, ... 600 million years ago. A list of events occurring in the history of our planet is given below.
Nowadays
. There are practically no places left on Earth that are not affected by human activity. 
20 million years ago
Neogene period. Mammals and birds are beginning to resemble modern species. The first hominids appeared in Africa. 
35 million years ago
The middle stage of the Pleistocene in the era of the Quaternary period. In the course of evolution, small and simple forms of mammals evolved into larger, more complex and diverse species. Primates, cetaceans and other groups of living organisms develop. The earth is cooling, and deciduous trees are spreading. The first species of herbaceous plants evolve. 
50 million years ago
Beginning of the tertiary period. After an asteroid destroyed the dinosaurs, surviving birds, mammals and reptiles evolved to occupy the vacated niches. A group of cetacean ancestors branches off from land mammals and begins to explore the oceans. 
65 million years ago
Late Cretaceous. Mass extinction of dinosaurs, marine and flying reptiles, as well as many marine invertebrates and other species. Scientists are of the opinion that the cause of the extinction was the fall of an asteroid in the area of the present Yucatan Peninsula (Mexico). 
90 million years ago
Cretaceous period. Triceratops and Pachycephalosaurs continue to roam the Earth. The first species of mammals, birds and insects continue to evolve. 
105 million years ago
Cretaceous period. Triceratops and Pachycephalosaurus walk around the Earth. The first species of mammals, birds and insects appear. 
120 million years ago
Early Cretaceous. The land is warm and humid, and there are no polar ice caps. The world is dominated by reptiles; the first small mammals lead a semi-hidden lifestyle. Flowering plants evolve and spread throughout the Earth. 
150 million years ago
The end of the Jurassic period. The first lizards appeared, primitive placental mammals evolved. Dinosaurs dominate all land. The world's oceans are inhabited by marine reptiles. Pterosaurs become the dominant vertebrates in the air. 
170 million years ago
Jurassic period. Dinosaurs are thriving. The first mammals and birds evolve. Ocean life is diverse. The climate on the planet is very warm and humid. 
200 million years ago
Late Triassic. As a result of mass extinction, 76% of all species of living organisms disappear. Population sizes of surviving species are also greatly reduced. Species of fish, crocodiles, primitive mammals, and pterosaurs were less affected. The first real dinosaurs appear. 
220 million years ago
Middle Triassic. The Earth is recovering from the Permian-Triassic extinction event. Small dinosaurs begin to appear. Therapsids and Archosaurs appeared along with the first flying invertebrates. 
240 million years ago
Early Triassic. Due to the death of a large number of land plant species, there is a low oxygen content in the planet's atmosphere. Many species of corals have disappeared; many millions of years will pass before coral reefs begin to rise above the surface of the Earth. Small ancestors of dinosaurs, birds and mammals survive. 
260 million years ago
Late Perm. The largest mass extinction in the history of the planet. About 90% of all species of living organisms disappear from the face of the Earth. The disappearance of most plant species leads to the starvation of a large number of species of herbivorous reptiles, and then predators. Insects are deprived of their habitat. 
280 million years ago
Permian period. The landmasses merge together to form the supercontinent Pangea. Climatic conditions are deteriorating: polar ice caps and deserts are beginning to grow. The area suitable for plant growth is sharply reduced. Despite this, four-legged reptiles and amphibians are diverging. The oceans abound with various species of fish and invertebrates. 
300 million years ago
Late Carboniferous. Plants develop a developed root system, which allows them to successfully colonize hard-to-reach areas of land. The area of the Earth's surface occupied by vegetation is increasing. The oxygen content in the planet's atmosphere is also increasing. Life begins to actively develop under the canopy of ancient vegetation. Evolving the first reptiles. A wide variety of giant insects appear. 
340 million years ago
Carboniferous (Carboniferous period). There is a mass extinction of marine organisms on Earth. Plants develop a more advanced root system, which allows them to more successfully invade new land areas. The concentration of oxygen in the planet's atmosphere is increasing. The first reptiles evolve. 
370 million years ago
Late Devonian. As plants develop, life on land becomes more complex. A large number of insect species appear. Fish develop strong fins that eventually develop into limbs. The first vertebrates crawl onto land. The oceans are rich in corals, various types of fish, including sharks, as well as sea scorpions and cephalopods. The first signs of a mass extinction of marine life are beginning to appear. 
400 million years ago
Devonian. Plant life on land becomes more complex, accelerating the evolution of terrestrial animal organisms. Insects diverge. The species diversity of the World Ocean is increasing. 
430 million years ago
Silur. The mass extinction wipes out half of the species diversity of marine invertebrates from the face of the planet. The first plants begin to colonize the land and populate the coastal strip. Plants begin to develop a conducting system that accelerates the transport of water and nutrients to tissues. Marine life is becoming more diverse and abundant. Some organisms leave reefs and settle on land. 
450 million years ago
Late Ordovician. The seas are teeming with life, and coral reefs appear. Algae are still the only multicellular plants. There is no complex life on land. The first vertebrates appear, including jawless fish. The first harbingers of mass extinction of marine fauna appear. 
470 million years ago
Ordovician. Marine life becomes more diverse and corals appear. Seaweeds are the only multicellular plant organisms. The simplest vertebrates appear. 
500 million years ago
Late Cambrian. The ocean is simply teeming with life. This period of rapid evolutionary development of many forms of marine organisms was called the “Cambrian Explosion”. 
540 million years ago
Early Cambrian. Mass extinction is taking place. During evolutionary development, marine organisms develop shells and an exoskeleton. Fossil remains indicate the beginning of the Cambrian Explosion.
In the history of the Earth, five major extinctions have been recorded - that is, phenomena of the disappearance of all representatives of a certain biological species. The last major extinction event occurred 65.5 million years ago and marked the death of the dinosaurs. The most massive extinction event occurred about 250 million years ago and led to the disappearance of about 95% of living beings. This phenomenon was called the “Permian mass extinction” and marked the end of the last period of the Paleozoic - the Permian geological period (which, unlike many other geological periods identified in Britain, was identified in 1841 in the area of the Russian city of Perm by the British geologist Roderick Murchison). After Perm, the Triassic began in the history of the Earth - the first period of the Mesozoic.
Over the past hundred-plus years, scientists have cited various causes for the Permian mass extinction.
For example, gradual changes in environmental conditions in the form of changes in the chemical composition of water in the world's oceans and in the atmosphere, changes in ocean currents, etc.
But still, more evidence has been given to the assumption that the Permian mass extinction was catastrophic in nature and was a consequence of either the fall of a large meteorite or increased volcanic activity.
The latest version received support several years ago, when scientists presented the results of a study of sedimentary rocks indicating high volcanic activity for several million years in the area where Siberia is now located. New similar data were presented by a group of Canadian scientists led by Stefan Grasby and published in the journal Nature Geoscience.
In geological layers corresponding in age, Canadian geologists discovered ash deposits - the cenosphere. They are microscopic hollow particles of fly ash that are formed when coal is burned. The same particles appear on Earth as a result of coal-fired power plants.
250 million years ago, these particles could have formed when, during the activity of the Siberian traps, molten matter burst out and passed through coal deposits.
The Siberian traps are one of the largest trap provinces in the world. Traps are a special type of continental magmatism, which is characterized by a huge volume of basalt outpouring in a geologically short time (millions of years) over large areas; the name comes from the Swedish word trappa (ladder), since in areas of trap magmatism a characteristic relief arises: the basalt layer is poorly eroded , and sedimentary rocks are easily destroyed. Traps are developed throughout the East Siberian Platform, in the Khatanga Trough, in the Minusinsk Basin; the magmatism zone also extends on the Eurasian shelf, at the bottom of the Kara Sea. In the area of their development there are the rivers Nizhnyaya Tunguska, Podkamennaya Tunguska, Tyung and others. Siberian traps make up the Putorana plateau. The center of trap magmatism was located in the Norilsk region.
As a result of the eruption of the Siberian traps, traces of which were found by scientists, a huge amount of toxic substances (for example, arsenic and chromium) appeared in the Earth’s atmosphere, which caused a “greenhouse effect” and a decrease in the amount of oxygen in the atmosphere. Ash ended up in the oceans, resulting in a change in the composition of sea water.
It is not surprising that after such a catastrophe, only a small part of living organisms remained on Earth.
According to scientists, they were able to identify three distinct layers of cenospheres over a time period of 500-750 thousand years, with the last of them formed immediately before the Permian mass extinction.
"The evidence is quite compelling," said Gregory Retalleck, a geologist at Oregon State University. Geophysicist Norman Sleep of Stanford University agrees, calling the Canadian team's findings an "extraordinarily major discovery."
As a result of the Permian mass extinction, many species disappeared from the face of the Earth, entire orders and even classes became a thing of the past. The extinction of old forms opened the way for many animals that had remained in the shadows for a long time: the beginning and middle of the Triassic period following Perm was marked by the formation of archosaurs, from which dinosaurs and crocodiles, and subsequently birds, descended. In addition, it was in the Triassic that the first mammals appeared.
Guys, we put our soul into the site. Thank you for that
that you are discovering this beauty. Thanks for the inspiration and the goosebumps.
Join us on Facebook And In contact with
On our planet, living side by side with us are creatures that appeared so long ago that, in comparison with them, humanity is a newborn baby, not even a couple of million years old.
website lists the most outlandish of them. Surprisingly well preserved!
Alligator pike
100 million years
One look at the alligator gar is enough to understand that this creature is not from our era. It is often called a "living fossil" due to its resemblance to an ancestor that lived 100 million years ago. This 3-meter freshwater predator with rows of long, needle-shaped teeth and a body enclosed in thick diamond-shaped scales, although it lives in water, is capable of breathing air.
Giant river stingray
400 Ma
The ancestors of this stingray existed as much as 400 million years ago. Its size can reach 2 meters in diameter, not counting the tail. The long and flexible tail is its main weapon: at the end there are two sharp spikes, one of which has sharp barbs for attack, and the other has deadly poison. The blow of the tail is so strong that it can break through the bottom of the boat.
Crocodile
250 Ma
Crocodiles are close in structure to dinosaurs and lived back in the Jurassic period (more than 250 million years ago), managing to remain almost unchanged to this day. Despite its danger to humans, the crocodile has always been a revered animal, and in Ancient Egypt - one of the gods. The closest living relatives of crocodiles are birds. By the way, crocodile tears actually exist - this is how the crocodiles’ body removes excess salts.
The largest crocodile in the world was caught in the Philippines. Its length was 6.17 meters, it was caught for 3 weeks by 100 people.
Echidna
110 Ma
The echidna resembles either a hedgehog or a porcupine, but in fact it is a close relative of the platypus. These small animals do not grow higher than 30 cm and have hardly changed during the 110 million years of their existence.
Coelacanth
100 million years
Coelacanths were considered extinct in the late Cretaceous period, when suddenly in 1938 a living coelacanth was caught in fishermen's nets. These fish can grow up to 2 meters in length and do not spawn, but produce a couple of dozen fully developed young.
Jellyfish
700 Ma
Jellyfish are found in almost all seas and oceans. There are 200 species of jellyfish: some of them prefer warm waters and live closer to the surface, some prefer colder water and live at the very bottom. The world's largest jellyfish is the arctic cyanide (or lion's mane). The length of the tentacles of these jellyfish can reach 37 meters.
The number of jellyfish even increases over time due to the constant catching of their natural enemies. However, there are also rare species. Jellyfish are 98% water, and one of the species, Turritopsis Nutricula, is the only immortal creature on the planet.
Goblin Shark
125 Ma
The ancestors of this shark existed 125 million years ago. While its larger relatives were dying out, the 3-meter goblin shark lived quietly at a depth of 200 meters, closer to the ocean floor. The goblin shark's long jaws can extend far forward, and it itself has an unusual pinkish color due to blood vessels located close to the skin. Despite its frightening appearance, it does not pose a great danger to people, and it is extremely rare to encounter them.
Hatteria
200 million years
Hatteria, or tuatara, is the oldest reptile on Earth. Hatteria helps scientists study the evolution of two entire species - lizards and snakes. The tuatara has a third eye - the parietal eye. It is not visible under the scales, but it is sensitive to light and heat and is responsible for biorhythms and thermoregulation. Hatterias live in New Zealand and often share burrows with petrels. All day long, while the birds are foraging for food, the hatteria rest in the hole, and when the petrels return, they go out to hunt at night.
The cause of the mass extinction of living beings 250 million years ago was climate cooling. This conclusion was reached by specialists from the Universities of Geneva and Zurich based on a study of ancient marine sediments carried out in the Nanpanjiang River basin in southern China.
We are talking about the so-called “great extinction” at the border of the Permian and Triassic geological periods - the largest in the history of our planet. It is believed that more than 95% of all marine species and more than 70% of terrestrial vertebrate species disappeared then. This phenomenon has not yet found a clear explanation in science. However, as noted in a message posted on the website of the University of Geneva, the findings of a group of researchers led by Urs Schaltegger and Hugo Bucher “completely challenge the scientific theories regarding this phenomenon, based on increasing CO2 in the atmosphere, and pave the way for a new vision history of the Earth's climate."
While working to determine the geological age of minerals contained in volcanic ash to establish a chronology of climate change, scientists became interested in processes that occurred 250 million years ago. They found a "gap" in the sediments consistent with falling sea levels. “The only explanation is that the water was frozen, and an ice age of 80 thousand years was enough to kill a significant part of marine life,” states the University of Geneva.
Experts explain the decrease in temperature on Earth during this period by the penetration of large amounts of sulfur dioxide into the stratosphere, which led to a decrease in solar heat reaching the surface of the planet. “We thus have evidence that the species disappeared during the ice age caused by the first volcanic activity in the Siberian Traps,” explained Urs Schaltegger. This period was followed by the formation of limestone by bacteria, which meant a return to more moderate temperatures.
As for the period of intense climate warming, which was previously considered the cause of the mass extinction of marine species, it, as Swiss scientists have established, occurred only 500 thousand years after the “great extinction.” “This study shows that climate warming is not the only explanation for past global environmental disasters on Earth: it is important to continue studying marine sediments to better understand the planet's climate system,” says the University of Geneva.
While studying sedimentary rocks in the Nanpanjiang River basin, Swiss experts used the uranium-lead dating method. Thus, the age of ancient deposits could be judged with an error of up to 35 thousand years, which “in itself is quite accurate for a period of 250 million years,” stated Urs Schaltegger.
The Permian extinction was one of the largest disasters that occurred in the long history of the Earth. The planet's biosphere has lost almost all marine animals and more than 70% of terrestrial representatives. Have scientists managed to understand the causes of extinction and assess its consequences? What theories have been put forward and can they be believed?
Permian period
To roughly imagine the sequence of such distant events, it is necessary to refer to the geochronological scale. In total, the Paleozoic has 6 periods. Perm is a period on the border of the Paleozoic and Mesozoic. Its duration is 47 million years (from 298 to 251 million years ago). Both eras, the Paleozoic and Mesozoic, are part of the Phanerozoic eon.
Each period of the Paleozoic era is interesting and eventful in its own way. The Permian period saw an evolutionary push that developed new forms of life, and the Permian extinction event that wiped out most of the Earth's animals.
What is the name of the period associated with?
“Perm” is a surprisingly familiar name, don’t you think? Yes, you were not mistaken, it has Russian roots. The fact is that in 1841 a tectonic structure corresponding to this period of the Paleozoic era was discovered. Nakhodka was located near the city of Perm. And the entire tectonic structure today is called the Pre-Ural foredeep.
Mass extinction concept
The concept of mass extinctions was introduced into scientific circulation by scientists at the University of Chicago. The work was carried out by D. Sepkoski and D. Raup. According to statistical analysis, 5 mass extinctions and almost 20 smaller-scale disasters were identified. Information for the last 540 million years was taken into consideration, since there is insufficient data for earlier periods.
The largest extinctions include:
- Ordovician-Silurian;
- Devonian;
- Permian extinction of species (the causes of which we are considering);
- Triassic;
- Cretaceous-Paleogene.
All these events took place in the Paleozoic, Mesozoic and Cenozoic eras. Their periodicity is from 26 to 30 million years, but many scientists do not accept the established periodicity.
The Greatest Environmental Disaster
The Permian extinction is the most massive disaster in the history of our planet. The marine fauna died out almost completely; only 17% of the total number of terrestrial species survived. More than 80% of insect species became extinct, which has not happened during other mass extinctions. All these losses occurred in about 60 thousand years, although some scientists suggest that the period of mass pestilence lasted about 100 thousand years. The global losses that the great Permian extinction brought brought a final line - having crossed it, the Earth's biosphere began evolution.
The restoration of the fauna after the greatest environmental disaster lasted a very long time. We can say that much longer than after other mass extinctions. Scientists are trying to recreate models by which a mass pestilence could occur, but so far they cannot even agree on the number of shocks within the process itself. Some scientists believe that the Great Permian Extinction 250 million years ago had 3 peak shocks, other schools of thought are inclined to believe that there were 8.
One of the new theories
According to scientists, the Permian extinction was preceded by another mass catastrophe. It happened 8 million years before the main event and significantly undermined the Earth's ecosystem. The animal world became vulnerable, so the second extinction within one period turned out to be the greatest tragedy. If it can be proven that two extinctions occurred during the Permian period, then the concept of the periodicity of mass catastrophes will be called into question. To be fair, let us clarify that this concept is disputed from many points of view, even without taking into account the possible additional extinction. But this point of view still holds scientific positions.
Possible causes of the Perm disaster
The Permian extinction is still controversial. Heated controversy revolves around the causes of the environmental cataclysm. All possible grounds are considered as equivalent, including:
- external and internal catastrophic events;
- gradual changes in the environment.
Let's try to look at some of the components of both positions in more detail to understand how likely they are to influence the Permian extinction. Photos of confirming or disproving findings are provided by scientists from many universities as they study the issue.
Catastrophe as the cause of the Permian extinction
External and internal catastrophic events are generally considered to be the most likely causes of the Great Dying:
- During this period, there was a significant increase in volcanic activity in the territory of modern Siberia, which led to a large outpouring of traps. This means that a huge eruption of basalt occurred in a geologically short time. Basalt is poorly eroded, and the surrounding sedimentary rocks are easily destroyed. As evidence of trap magmatism, scientists cite the example of vast territories in the form of flat stepped plains on a basaltic base. The largest trap area is the Siberian Trap, formed at the end of the Permian period. Its area is more than 2 million km². Scientists from the Nanjing Institute of Geology (China) studied the isotopic composition of the rocks of the Siberian traps and found that the Permian extinction occurred precisely during the period of their formation. It took no more than 100 thousand years (before that it was believed that it took a longer period of time - about 1 million years). The activity of volcanoes could provoke the greenhouse effect, volcanic winter and other processes that are destructive to the biosphere.
- The cause of the biosphere catastrophe could be the fall of one or more meteorites with a large asteroid. A crater with an area of more than 500 km (Wilkes Land, Antarctica) is cited as evidence. Also, evidence of impact events was found in Australia (Bedout structure, Northeast of the continent). Many of the samples obtained were later refuted in the process of deeper study.
- One of the possible reasons is considered to be a sharp release of methane from the bottom of the seas, which could lead to the total death of marine animal species.
- What could have led to a catastrophe was the acquisition by one of the domains of living unicellular organisms (archaea) of the ability to process organic matter, releasing large volumes of methane.
Gradual changes in the environment
- Gradual changes in the composition of sea water and the atmosphere, resulting in anoxia (lack of oxygen).
- Increasing dryness of the Earth's climate - the animal world was unable to adapt to the changes.
- Climate change has disrupted ocean currents and reduced sea levels.
Most likely, there was a whole complex of reasons, since the disaster was massive in nature and occurred over a short period.
Consequences of the Great Dying
The Great Permian extinction, the causes of which the scientific world is trying to establish, had serious consequences. Entire units and classes disappeared completely. Most of the parareptiles became extinct (only the ancestors of modern turtles remained). A huge number of arthropod and fish species have disappeared. The composition of microorganisms has changed. In fact, the planet was deserted, at the mercy of fungi that fed on carrion.
After the Permian extinction, the species that survived were those that were best adapted to overheating, low oxygen levels, lack of food, and excess sulfur.
A massive biosphere cataclysm opened the way for new species of animals. The Triassic was the first to reveal archosaurs (the ancestors of dinosaurs, crocodiles and birds) to the world. After the Great Dying, the first species of mammals appeared on Earth. It took from 5 to 30 million years to restore the biosphere.