Earth is home to an abundance of life that is both complex and diverse. Yet, if you look back in time on a geologic scale—millions and even billions of years—life looks much simpler and more homogeneous than it does today. Why is that?

The answer is extinction. Over the course of eons, lifeforms have evolved on Earth only to be completely wiped out, leaving us with only the fossilized traces of their presence. Why did these events happen? How did they transform the progress of evolution? And how was life able to recover after every major extinction event? In Earth’s Great Mass Extinctions, Dr. Rachel Phillips of the University of South Carolina will take you back to the Earth’s distant past to explore how death on a grand scale transformed the nature of life on our astonishing planet.