View full lesson: http://ed.ted.com/lessons/how-a-single-celled-organism-almost-wiped-out-life-on-earth-anusuya-willis

There’s an organism that changed the world. It caused the first mass extinction in Earth’s history … and also paved the way for complex life. How? Anusuya Willis explains how cyanobacteria, simple organisms that don’t even have nuclei or any other organelles, wrote a pivotal chapter in the story of life on Earth.

Lesson by Anusuya Willis, animation by Augenblick Studios.