Every living organism, from trees to whales to bacteria, shares a common ancestor that lived billions of years ago.

This microscopic life form, known as Last Universal Ancestor (LUCA), existed long before complex cells evolved. It is considered an organism, a simple, single-celled life form that lived billions of years ago and is the common ancestor of all life on Earth.

Many scientists think the earliest life may have emerged near deep-sea hydrothermal vents, where chemical energy and mineral-rich conditions could support simple organisms. However, the exact environment of life’s first ancestor remains uncertain.

Over immense spans of time, its descendants spread and diversified, eventually giving rise to all life on Earth, including you.