Our common ancestor
One cell from which everything alive today descends
See it on the timeline →In depth
LUCA, the last universal common ancestor, is reconstructed by looking for genes shared across all three domains of life. The result is a surprisingly detailed profile: an anaerobe living on hydrogen and carbon dioxide, using iron–sulphur chemistry, tolerant of high temperature — in short, something at home beside a hydrothermal vent. All life still shares the genetic code, ATP as energy currency and the ribosome as protein factory. These are so universal they must already have been present in LUCA. Other branches of early life probably existed, but left no descendants.
For children
Somewhere in the early ocean lived one particular cell. It was not the first cell, but it is the last one from which everything alive today descends — bacteria, fungi, trees, blue whales and you. We call it LUCA, and we know it exists because every living thing still runs on the same basic recipes.
Connects to
Part of Terra Saga — the story of Earth on a timeline. terrasaga.org