‘Mass extinction‘ is a very familiar term in wildlife discussions. A species is considered extinct when the last surviving organism or animal dies. And mass extinction is called mass extinction. Over its 4.5 billion year history, this ever-beautiful pattern has seen from tiny single-celled bacteria to complex-brained human species. Observed the diverse fauna that inhabited the earth from the eruption of molten lava on the eve of creation. However, although many species of animals have roamed the earth since the beginning of creation, currently many species have been wiped out from the earth. And one of the biggest drivers behind the extinction of these primitive animal species is the mass extinction caused by natural disasters. Today’s event is about ten such mass extinctions in the history of the world.
Oxygen crisis
Time: 230 million years ago
One of the most important events in the history of life took place approximately 2.5 billion years ago. The bacteria are then able to achieve photosynthesis by using sunlight to break down carbon dioxide and release energy. Unfortunately, a major byproduct of this photosynthesis is oxygen, which poses a threat to some organisms. Those animals that appeared on earth 350 million years ago could not survive in the presence of oxygen. Even today, some bacteria exist on Earth, which die in the presence of oxygen. About 200 million years after bacteria evolved the ability to perform photosynthesis, Earth’s atmosphere accumulated substantial amounts of oxygen. As a result, organisms that cannot tolerate the presence of oxygen die off.
Snow globe world
Time: 700 million years ago
According to some established hypotheses, about 700-650 million years ago, every inch of the Earth was covered with a white sheet of ice. Many photosynthetic species became extinct at that time from the ice-gloved Earth. At that time, so much ice had accumulated in the polar regions that sunlight would be reflected back into space. As a result, the temperature of the earth gradually decreases. Photosynthesis was not possible because of the cold weather and insufficient sunlight. As a result, the food chain collapses and many organisms become extinct. Global glaciation also altered the course of the Earth’s carbon cycle, creating a shortage of sufficient carbon dioxide for photosynthesis.
End-Ediacaran mass extinction
Time: 542 million years ago
Many people may not be familiar with the Ediacaran period. Because, from the scientific community, this era has been identified around 2004. According to the geological timeline, the End-Ediacaran mass extinction occurred about 542 million years ago, at the boundary between the Ediacaran and Cambrian periods. This was followed by the Cambrian period, in which biodiversity developed rapidly. Complex multicellular organisms emerged in marine environments after the End-Ediacaran period. Many erikadans, the ancestors of Earth’s complex, multicellular organisms, were crushed to extinction during this mass extinction.
Cambrian-Ordovician mass extinction
Time: 488 million years ago
The Cambrian-Ordovician mass extinction continued for millions of years on the primitive Earth . Following this mass extinction, the Cambrian period ended and the Ordovician period began. During this time, countless species of marine organisms, such as trilobites, brachiopods, graptolites, conodonts, etc., became extinct. In terms of numbers, 60% of invertebrate species, and 85% of marine species were lost to extinction during that time.
Ordovician mass extinction
Time: 447-443 million years ago
The Ordovician mass extinction , which occurred during the Paleozoic era, consisted of two separate extinctions. One occurred 447 million years ago, and the other 443 million years ago. Then the world’s marine invertebrate population plummeted by as much as 60 percent. Brachiopods, bivalves and corals are notable among them. The cause of the Ordovician extinction still creates a haze of mystery in the scientific community. This is attributed to a supernova explosion near Earth, which experts believe brought harmful gamma rays to Earth. The release of toxic metals from the seabed is also believed to be one of the causes of this mass extinction.
The Devonian mass extinction
Time: 375 million years ago
After the Ordovician mass extinction, the Devonian mass extinction was the second catastrophe of the Paleozoic epoch. The Devonian mass extinction, which occurred about 375 million years ago, was only 65 million years apart from the previous Great Extinction. Together, the two mass extinctions of the Paleozoic era wiped out about 80 percent of aquatic and terrestrial species from the Earth. Scientists believe that the Devonian mass extinction was completed in two stages. In the first step, the ocean environment suddenly starts to become toxic. As a result, a large proportion of marine plants have adapted to land. Since there was no oxygen producer in the sea, there was a severe oxygen shortage. As a result, most of the mariners fell to their death.
Permian mass extinction
Time: 250 million years ago
The Paleozoic era is considered a dark chapter in the history of life. Because, animals have faced three mass extinctions in this era. The Permian mass extinction completed the final nail in the coffin of the Paleozoic era . This Permian mass extinction is referred to as the ‘mother’ of all mass extinctions. About 250 million years ago, 95% of marine and 70% of terrestrial species disappeared in this extinction. This mass extinction was so severe that it took about 10 million years for species on Earth to return to a more or less normal state.
Why did this mass extinction happen? Scientists could not give a definite answer. According to them, about 96% of the species were lost from the Earth due to volcanic eruptions and large meteorites. Eruptions and meteorites combined to cause this cataclysm. At that time, due to the increase in methane content in the air at an excessive rate, there was a great negative impact on the weather-climate. Temperatures beyond the extremes made Earth completely uninhabitable. The combination of these controls wipes out all but a handful of creatures from the earth. This is how the Paleozoic era ends, and the Earth enters the Mesozoic era.
Triassic-Jurassic mass extinction
Time: 200 million years ago
Although the Cretaceous-Tertiary mass extinction ended the dinosaurs’ reign on Earth, their decline began in the Triassic-Jurassic period.Through mass extinction. It was this mass extinction that drew the line in thick spots to their long monopoly on the gray earth. The Triassic-Jurassic mass extinction, which took place about 200 million years ago, basically refers to a series of small mass extinctions. Its period lasted for a long 18 million years, and during this period about 50% of the species that once roamed the earth were lost forever. Scientists blame volcanic eruptions as the reason for this mass extinction, which has been burning like embers for a long time. Then many living species had to be lost in the womb of the universe in the molten lava flow of the volcano. A large number of eruptions increase the amount of methane in the air at an excessive rate, making the climate completely uninhabitable. Unable to withstand this brutal shock of nature, many terrestrial amphibians, archosaurs and therapsids joined the journey to extinction.
Cretaceous-Tertiary mass extinction
Time: 65 million years ago
The last mass extinction on a non-human Earth was the Cretaceous-Tertiary mass extinction. Looking at the timeline, this mass extinction is the longest span of time. Scientists have many signs and proofs of this extinction. Although some species of dinosaurs survived the Triassic-Jurassic mass extinction, they could no longer protect themselves from the Cretaceous-Tertiary mass extinction.
With sufficient evidence at hand, scientists have been able to give a clear and clear understanding of this mass extinction. It was triggered by a huge meteorite or asteroid. The meteors or asteroids, which took the form of fully burning craters due to friction with the Earth’s atmosphere, hit the Earth’s chest with force. The animals of the world were in no way prepared to face the cruel consequences. Whether terrestrial or aquatic, all join in the great journey of extinction. Animals near the explosion could not save themselves, instead the entire atmosphere was filled with dust and poisonous gases. As a result, 75% of the species of the then living world disappeared from the earth.
Man-made mass extinction
All of the above discussions were mass extinctions brought about by natural disasters before humans came to earth. However, many people may not know that many animals have been wiped out by humans. Woolly mammoth, long-toothed tiger, gigantic wombat, beaver have disappeared from the earth only because of humans.
Homo sapiens colonized Australia about 45,000 years ago. At that time, kangaroos weighing up to two hundred kilograms, which were about two meters long, were often seen on the Australian soil. Marsupial lions ruled the continent, which were the largest predators of the time. All the silence of nature would be broken in an instant by the loud footsteps of a flock of birds twice the size of flightless ostriches. Diprotodon, a monstrous animal, roamed fearlessly in the forest. The average weight of each of them was close to two and a half tons. Within a few thousand years of sapiens settling in Australia, almost all giant animals were listed as extinct.
