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The Great Oxidation Event -

The Great Oxidation Event, also known as the Oxygen Crisis and the Oxygen Catastrophe, occurred about 2,300 million years ago, during the Paleoproterozoic era.

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The Great Oxidation Event -

Back then, our planet’s atmosphere had just 0.03% of today's oxygen levels. However, the levels started to rise, leading to new life developing, but also driving much of Earth’s life to extinction.

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The Great Oxidation Event -

Scientists theorize that the culprit might have been one of Earth's earliest prokaryotic organisms, called cyanobacteria. These organisms started to photosynthesize and release oxygen.

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End-Botomian mass extinction -

During this period, not one, but two extinction intervals occurred, approximately 513 to 509 million years ago.

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End-Botomian mass extinction -

The Cambrian Period is pretty important. This was when organisms made the transition from unicellular to multicellular, including hard-shelled animals (e.g. trilobites). Until, of course, mass extinction wiped about 83% of these from Earth.

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End-Botomian mass extinction -

The reason, however, still puzzles scientists to this day, with several theories put forward, including "sea-level change, marine anoxia, carbon isotope excursions, and eruptions of LIPs (large igneous provinces)," according to the University of Leeds.

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Ordovician–Silurian extinction events -

The Ordovician–Silurian extinction events, also known as the Late Ordovician mass extinction, were two events that occurred somewhere between 450 and 440 million years ago. These are considered one of the largest extinction events on Earth.

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Ordovician–Silurian extinction events -

The events were responsible for the extinction of 85% of all marine species on Earth. Trilobites, graptolites, bryozoans, brachiopods, and conodonts were virtually wiped out from our planet.

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Ordovician–Silurian extinction events -

The first event is believed to have been due to cooling and widespread glaciation. The second event is usually attributed to warming and decreased oxygen levels, possibly linked to volcanism. Though all these are just theories.

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Lau event -

The Lau event, also known as the Lau/Kozlowskii extinction, occurred during the Silurian period, around 420 million years ago. It was responsible for the extinction of 23% of all marine animals. Some species, such as graptolite, saw a reduction as high as 70%.

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Lau event -

It is believed that the deoxygenation of the ocean and the "proliferation of sulfidic ocean conditions," contributed to the mass extinction.

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Late Devonian extinction -

This mass extinction is believed to have been a combination of eight to 10 events that lasted between two to four million years to 20-25 million years. It occurred during the Devonian period and was responsible for the extinction of 70-80% of all animal species! Though it affected mostly marine life.

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Late Devonian extinction -

It is thought that these events were mostly caused by low levels of oxygen in the oceans. The reasons why the levels dropped are still up for debate.

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Carboniferous rainforest collapse -

This extinction event occurred around 307 million years ago and had a huge impact on Earth’s flora and overall landscape.

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Carboniferous rainforest collapse -

The reason why these "coal forests" (this is where most of the coal extracted years later comes from) were wiped out is still unknown. There are, of course, numerous theories, ranging from climate change to volcanism.

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Permian–Triassic extinction event -

The Permian–Triassic extinction event, also known as End-Permian Extinction, the Great Dying, and the P–T event, is considered Earth’s most brutal mass extinction event. It occurred about 251.9 million years ago.

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Permian–Triassic extinction event -

The event wiped out between 77 and 96% of all invertebrate marine species from Earth. On land, 70% of all vertebrate species went extinct, as well as numerous insect species.

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Permian–Triassic extinction event -

Unlike other mass extinction events, scientists can’t find evidence that it was preceded by an atmospheric or oceanic change, calling it "geologically instantaneous."

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Triassic–Jurassic extinction event -

Also known as the end-Triassic extinction, the event occurred between the Triassic and Jurassic periods, about 201 million years ago. It led to the extinction of 34% of marine genera, as well as up to 20% of marine families. In total, about 76% of marine and terrestrial species on Earth were wiped out.

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Triassic–Jurassic extinction event -

Climate change, including the acidification of the ocean and an increase in CO2 in the atmosphere (possibly linked to volcanic activity), might be to blame.

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Cretaceous–Paleogene extinction event - This event, which occurred around 65 million years ago, was caused by an asteroid impact. The result? About 75% of all life on Earth went extinct, including dinosaurs.

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Cretaceous–Paleogene extinction event -

The impact took place at the tip of the Yucatán Peninsula in Mexico. Then, a prolonged period of cold and darkness, known as "impact winter," followed. It is estimated that larger animals were unable to survive this period.

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Eocene–Oligocene extinction event -

The end of the Eocene period and the beginning of the Oligocene, about 33.9 million years ago, was marked by this event which led to the extinction of 66% of all species in Europe and Asia.

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Eocene–Oligocene extinction event -

This mass extinction event was due to Earth’s cooling. The climate was likely affected by numerous things, including less CO2 in the atmosphere and changes in ocean circulation.

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Pliocene–Pleistocene boundary extinction -

Around 2.6 million years ago, most giant marine fauna, such as the megalodon (a giant shark), disappeared from our oceans. In fact, it is estimated that about 36% of marine genera became extinct.

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Pliocene–Pleistocene boundary extinction -

One of theories put forward by scientists is that particles from a supernova (exploding star) entered Earth, leading to mutations and cancers that affected mostly larger animals.

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Holocene extinction -

The Holocene extinction, also known as the Anthropocene extinction, is arguably a mass extinction event caused by human activity. Many scientists agree this is currently undergoing.

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Holocene extinction -

The time frame by which this is occurring is also different from previous mass extinctions, with the species extinction rate being between 100 to 1,000 times higher than it would naturally occur. "For example, 477 vertebrates have gone extinct since 1900, rather than the nine that would be expected at natural rates," explains The Guardian.

Sources: (Grunge)

See also: How to eat to save the planet

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