GENERAL GEOLOGY

Detailed explanation-1: -Scientists have debated until now what made Earth’s oceans so inhospitable to life that some 96 percent of marine species died off at the end of the Permian period. New research shows the “Great Dying” was caused by global warming that left ocean animals unable to breathe.

Detailed explanation-2: -What causes mass extinctions? Past mass extinctions were caused by extreme temperature changes, rising or falling sea levels and catastrophic, one-off events such as huge volcanic eruptions or an asteroid hitting Earth.

Detailed explanation-3: -The second period of extinction, during the Devon Age, happened around 359 million years ago. A relentless meteor shower is believed to be one of the causes of mass extinction. Other causes include a drastic decrease in oxygen levels globally, the increased activity of tectonic plates, and climate change.

Detailed explanation-4: -End Ordovician Crisis Considered to be the second largest ‘extinction’ event, after the Permian extinction. This event occurred approximately 450-440 million years ago. This event, as with the Devonian crisis interval appears to not be a time of increased extinction but rather decreased speciation (or origination).