1 Calories Burned For SparkPeople 28 Day Bootcamp (Boot Camp) DVD: 12-Minute Cardio Burst Workout. 2  Calories Burned For SparkPeople 28 Day Bootcamp (Boot Camp) DVD: 12-Minute Short Cardio Sculpt Workout.
Anther occurred when the Cretaceous period became the Tertiary about 65 million years ago, when 75 percent of species disappeared. This article is about the first mass extinction at the end of the Ordovician geological period 440 million years ago, when about 86 percent of species were killed.
Clues from the fossil record give us information about what species went extinct and when, but how the extinction happened in the first place has been a puzzling question for scientists. One of the biggest theories involves a series of volcanic eruptions, which took place about 250 million years ago in Siberia. According to Smithsonian's Mass Extinction, these eruptions spewed enough lava to bury the continental US under a layer 1,000 feet deep. Wikimedia Commons Part of the Siberian traps.