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Life

Life learns to use sunlight

3.40 billion yrs ago

Cyanobacteria invent photosynthesis

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In depth

Oxygenic photosynthesis was arguably the single most important invention in the history of life. Cyanobacteria learned to split water using sunlight and use the hydrogen to build sugars, with oxygen as the waste product. That gave life a practically unlimited energy source, independent of sea-floor chemistry, and let the biosphere grow by orders of magnitude. The downside was that the waste product was poisonous to almost everything then alive.

For children

Some tiny bacteria worked out how to use sunlight as food. They took in light, water and air — and breathed out oxygen. It is the same trick plants use today, and it changed the entire planet.

Connects to

Part of Terra Saga — the story of Earth on a timeline. terrasaga.org