Life on earth is what makes the planet special and habitable and there are times life on earth has been hit with threats like extinction and it almost wiped out life on earth, but happily, life remained. These threats occur in one in a million years, and they are events that cannot be easily forgotten. 

Today there is ongoing research and development geared towards making life on earth multi-planetary to save us from a massive extinction level. 

Here are a few times, life on earth almost went extinct; 

The Permian Extinction.

This event took place 252 million years ago, it took about 10 million years for the planet to fully recover from it. 96% of all marine life and 70% of all land-based species disappeared - an unprecedented rate of species loss. This mass extinction was so extreme that it is often referred to as “the great dying,” and it dramatically reshaped all corners of life on Earth. It's the only mass extinction event known to have affected insects, some of the most resilient creatures on the planet.

There are many theories regarding the cause of this great dying - volcanic eruptions, earthquakes, increases in atmospheric methane, an asteroid, and even acid rain, etc. Researchers worldwide continue to explore all the possibilities.

The Cretaceous extinction that wiped out the dinosaurs.

This is one of the most famous mass extinction events of all. It killed all dinosaurs on earth and was directly responsible for the rise of mammals. More so 70% of all species were killed during this event. Nonavian dinosaurs, pterosaurs, ammonites and other large marine reptiles that dominated the oceans were all killed.

The most popular theory behind what caused this extinction was an asteroid impact that was powerful enough to change the Earth’s homeostasis. There are a lot of geological proofs to back this claim.

This impact filled the air with debris, causing a tremendous degradation of the atmosphere and killing nearly every animal over 55 pounds - including the dinosaurs. 

The Great Oxygenation almost suffocated the world.

This event occurred 2.5 billion years ago, and it's widely believed to be the first-ever mass extinction event. There was very little oxygen in the atmosphere. Life was relatively easy, and it evolved beyond simple bacteria, most of which were anoxic - Anoxic bacterias don’t need oxygen to survive, more so oxygen is highly toxic to them.

Then came the evolution of cyanobacteria, a new type of life that could harness the sun's energy - photosynthesis. And this affected Anoxic bacterias. This new way of survival for cyanobacteria's had great consequences, filling the environment with a waste byproduct of the process: oxygen. Then the atmosphere began to fill up with oxygen, suffocating most anoxic bacterias on the planet. 

The effects of oxygen in the atmosphere nearly wiped out the cyanobacteria themselves. When chemicals in the atmosphere reacted with oxygen, it altered the composition of the air and this led to one of the worst global cooling events in Earth’s history - resulting in oceanic freezes across the planet and the near-death of all remaining life.


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