Complex Life May Be a Billion Years Older Than We Thought

The origins of complex, nucleated cellular life – everything from amoebas to humans – may date back a lot further in Earth's history than we thought.

A new study tracing the earliest steps toward complex life suggests that this transformation from simpler ancestors began almost 3 billion years ago – long before our planet had the oxygen levels needed to support a thriving eukaryotic biosphere.

That's almost a billion years earlier than some estimates place the rise of complex cells, pointing to a surprisingly long, drawn-out evolutionary buildup rather than a rapid leap in complexity.

There are many ways to group life on Earth, but possibly the most basal distinction is between prokaryotes and eukaryotes.

Prokaryotes , a group that includes bacteria and archaea, were the first lif