TED-Ed: How a single-celled organism almost wiped out life on Earth - Anusuya Willis

Cyanobacteria, ancient single-celled organisms, were pivotal in Earth's history by introducing free oxygen into the atmosphere through photosynthesis. This led to the Great Oxygenation Event, causing a mass extinction and a global ice age. Over time, life adapted, leading to the evolution of complex organisms. Cyanobacteria also played a role in the development of plant cells through endosymbiosis. Today, they continue to influence Earth's ecosystems by producing oxygen and fixing nitrogen.

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