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.
An extinction event (also known as a mass extinction or biotic crisis) is a widespread and rapid decrease in the amount of life on Earth.Such an event is identified by a sharp change in the diversity and abundance of multicellular organisms. This extinction event lasted perhaps as long as 20 million years, and there is evidence for a series of extinction pulses within this period. 2  OrdovicianâSilurian extinction events (End Ordovician or O-S): 450â440 Ma at the Ordovician-Silurian transition.