The Permian-Triassic Extinction Occur

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Approximately 250 million years ago, the earth underwent the most catastrophic extinction event in its entire history. The mass extinction occurred on the Permian-Triassic border on the geological timescale, and is appropriately nicknamed, “The Great Dying”. It has resulted in the most extinction occurrences, expressed in a %, than any of the other mass extinctions in geological time, as seen in FIGURE 1. The Permian Extinction created a huge setback for Earth’s fauna and its diversity. During the short duration of this event, the earth lost 90-96% of all species (Stanley, 2016). This extinction event occurred due to multiple mechanisms within a mere 1-million-year period, causing intense and uninhabitable living conditions in both the Earth’s …show more content…

This supercontinent formed when two large landmasses collided due to the workings of plate tectonics. During these geological settings, Earth had large regions of shallow seas creating great marine biodiversity. However, the merging of Gondwana and Laurasia reduced the total length of coastal areas. These settings, allowed life to flourish and diversify, but concentrated organisms in the shallow water along the coasts. This deepened the risk of an extinction if these specific areas on Earth’s surface were to be targeted.
The Great Dying is an occurrence caused by multiple mechanisms which weakened a range of ecosystems, making them susceptible to further damage. These different mechanisms build up over time, causing maximum destruction across large regions. The Permian Extinction resulted from a combination of sea-level changes, volcanic activity, alterations of ocean chemistry and asteroid impacts. The outcome of losing over 75% of species, classifying it as a mass extinction, only occurs through the specific timing and order of these …show more content…

The coverage of continental crust from pole to pole, as seen in FIGURE 1, affected the ocean currents and decreased the circulation of water. This “unmixed” water created long-term deep sea anoxia, meaning there is little to no oxygen available to support most life forms. This oxygen-poor environment and a lack of ventilation resulted in the deposit of black shales on the ocean floor. Ocean acidification also incurred with water becoming high in CO2 and of low pH. This caused the selective extinction of calcifying organisms which had thrived since the start of the Paleozoic era, such as the trilobite! In addition to these deadly alterations to the Permian ocean, there were high concentrations of hydrogen sulfide creating a place for sulfur reducing bacteria to flourish. The change to the Panthalassa Ocean’s chemistry proved lethal to marine life and its diversity, and killed off species known for surviving harsh living conditions in the

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