The Ordovician-Silurian extinction (440 to 450 million years ago) was the first “great extinction” that occurred about 450 million years ago. It is considered the second largest extinction in history if measured by the number of species destroyed with 85% of fish species and 60% of biological species destroyed. The most accepted cause of extinction is a gamma-ray burst of a near-Earth star that caused a sharp drop in atmospheric carbon dioxide. This created an ice age that lasted 0.5 – 1.5 million years. Lower sea levels combined with the cold of glacial ice brought about a mass extinction in the Ordovician period. Late Devonian Extinction: Over 365 million years ago, one of the five largest and most feared mass extinctions in Earth’s biological history. It happened about 360 million years ago, killing 70% of all living things. Archaeological evidence indicates that this mass extinction could last up to 20 million years. Although it is one of the scariest mass extinctions in the world, its cause is still an unsolved mystery. Permian-Triassic extinction: about 253 million years ago is likened to the bloodiest massacre in Earth’s history. This terrible extinction event wiped out 95% of all species on earth. The main reason is due to the extremely strong tectonic movement of the Earth’s crust. Magma eruptions from fault plates engulfed the entire Earth’s surface in a sea of ​​fire. The increase in dust and carbon dioxide causes the greenhouse effect to warm the Earth. Changes in ocean currents cause great impacts on the ecosystem, ocean circulation becomes stagnant, lack of oxygen. Life now becomes extremely fragile. Triassic-Jurassic Extinction: About 201 million years ago was an extinction that took place about 199.6 million years ago that completely wiped out half of all living things on Earth. It is still not certain what caused the disaster. Scientists predict that a large volcanic eruption has occurred. However, studies have shown quite accurately the time when the extinction took place and the meteor impact that created Lake Manicouagan (Canada). This evidence proves that it is possible that the collision was the direct cause of this extinction. The Cretaceous – Paleogene extinction occurred about 66.5 million years ago, marking the end of the Mesozoic and the beginning of the Cenozoic with the Paleogene period. About 75% of species went extinct after this terrible event. Scientists theorize that this extinction event was caused by one or more simultaneous disasters, such as the powerful impact of meteorites (creating the Chicxulub craters in Mexico, Boltysh in Ukraine). or due to a drop in sea level, powerful volcanic eruptions creating the phenomenon of “Deccan traps” that seriously destroy the Earth’s biosphere. Currently, humans are in the early stages of the latest mass extinction, which is happening much faster than any other species. Since 1970, vertebrate populations have decreased by an average of 68% and now more than 35,000 species are considered endangered. In the 20th century alone, as many as 543 species of terrestrial vertebrates became extinct. Since the beginning of the industrial revolution in 1760, humans have been a major factor in Earth’s current environmental crisis. From greenhouse gas emissions and ozone depletion to deforestation, plastic waste and the illegal animal trade, humans have been proactively depriving the world of some species and threatening many others. Please watch the video: Strange and Unique Natural Phenomena in the World. Source: Strange story VN&TG

Climate change is one of the main causes of extinctions worldwide. 5 mass extinctions Dinosaurs became extinct in the Jurassic, more than 200 million years ago. * Ordovician-Silurian Extinction: About 440 million years ago The first mass extinction on Earth occurred at a time when organisms such as corals and shellfish filled the world’s shallow waters but had yet to venture to land. Life itself has begun to spread and diversify, first appearing around 3.7 billion years ago. But about 440 million years ago, a climate change caused sea temperatures to shift, and much of the life in the ocean died out. At the end of the Ordovician, mass glaciations covered the southern supercontinent, Gondwana. According to a study published in the journal Oceanology, glaciation on this scale has stripped away high proportions of the world’s water and dramatically lowered global sea levels, depriving the world of vital habitats. species, destroying the food chain and reducing fertility, according to a study published in the journal Oceanology. However, not all scientists agree with this. According to National Geographic, other theories suggest that the toxic metal may have dissolved into seawater during periods of oxygen depletion, wiping out marine life. Other scientists suggest that a gamma-ray burst from a supernova ripped through a giant hole in the ozone layer, allowing deadly ultraviolet radiation to kill life below. According to APS News, there is a Another theory is that volcanoes are the cause. * Late Devonian Extinction: Over 365 million years ago The Devonian period witnessed the rise and fall of many prehistoric marine species. Although by this time animals had already begun to evolve on land, most of life was swimming through the oceans. Until vascular plants, such as trees and flowers, have the potential to cause a second mass extinction. According to the BBC, as plants develop roots, they inadvertently transform the land they inhabit, turning rocks and rubble into soil. This nutrient-rich soil then runs into the world’s oceans, causing algae to bloom on a massive scale. These blooms essentially created giant “dead zones,” areas where algae take oxygen from the water, suffocating marine life and wreaking havoc on the marine food chain. Species that could not adapt to reduced oxygen levels and lack of food died. However, this theory is still being debated, and some scientists believe that volcanic eruptions are responsible for the drop in oxygen levels in the ocean, according to a study in the journal Geology. A species of sea monster that has been wiped out from the world’s oceans is the 10 m long armored fish called Dunkleosteus . * Permian-Triassic extinction: ~253 million years ago This extinction event is the largest event that has ever occurred on Earth. It wiped out about 90% of all species on the planet and wiped out the reptiles, insects and amphibians that roamed the land. What caused this catastrophic event was a period of rampant volcanism. According to the Sam Noble Museum in Oklahoma, in the ocean, rising levels of carbon dioxide dissolve into the water, poisoning marine organisms and depriving them of their oxygen-rich water. Rising sea temperatures also reduce oxygen levels in the water. Corals are one of the hardest hit groups of marine life – it takes 14 million years for oceanic reefs to rebuild as they once were. * Triassic-Jurassic Extinction: About 201 million years ago The Triassic period was the time when dinosaurs began to inhabit the world. Unfortunately, many volcanoes were also erupting at that time. While it’s still not clear exactly why this fourth mass extinction occurred, scientists suggest that massive volcanic activity occurred in an area of ​​the world now covered by the Atlantic Ocean. cover . Similar to the Permian extinction, volcanoes released huge amounts of carbon dioxide, causing climate change and devastating life on Earth. Global temperatures rise, ice melt, sea levels rise and acidification. As a result, many marine and terrestrial species became extinct; These include large prehistoric crocodiles and several species of flying pterosaurs. All dinosaurs were killed in the fifth mass extinction. Scientists estimate that many species that can fly, burrow or dive into the depths of the ocean survive. For instance, the only true descendants of dinosaurs living today are modern-day birds – more than 10,000 species are thought to have descended from survivors. Is the 6th going? According to The Conversation, scientists define a mass extinction when about three-quarters of species die out in a short geological time, i.e. less than 2.8 million years. Currently, humans are in the early stages of the latest mass extinction, which is happening much faster than any other species. According to the International Union for Conservation of Nature (IUCN), since 1970, populations of vertebrate species have decreased by an average of 68% and now more than 35,000 species are considered threatened with extinction. During the 20th century, as many as 543 species of terrestrial vertebrates became extinct, according to a research paper in the journal PNAS. Since the beginning of the industrial revolution in 1760, humans have been a major factor in Earth’s current environmental crisis. From greenhouse gas emissions and ozone depletion to deforestation, plastic piling and the illegal animal trade, humans have been proactively depriving the world of some species and threatening many others. Ecotourism is an industry that drives conservation efforts around the world, but it is on the verge of collapse since global travel restrictions were introduced. Without tourist income, conservationists are having a hard time protecting vulnerable species from poaching, while the COVID-19 pandemic is intensifying. The New York Times reported. Rhinos in Botswana, feral cats in South America and tigers in India have all been targeted in the past year. In the context of the current pandemic, the wildlife market has become the focus of attention for not only being environmentally irresponsible but also potentially endangering human health through infectious diseases. from animals to humans – such as the COVID-19 pandemic. These markets, which trade in live exotic animals or products derived from them, are found all over the world. For example, bear farms in Asia trap 20,000 Asian black bears for bile, leading to a decline in wild populations. Another potential solution to combat extinction could be the cloning of species. In February 2021, scientists revealed they had successfully cloned a black-footed ferret from an animal that died more than 30 years ago. Native to North America, these small mammals were thought to be extinct until a small colony was found in the early 1980s, where they were engaged in breeding and reintroduction programs. across America. The cloning process is similar to that of Dolly the sheep in the early 1990s.