Complex life may have begun 1.5 billion years earlier than thought

The marine fossils contain the largest macroscopic eukaryotes despite only measuring 11 inches across.

A discovery in northern China has led researchers to believe complex life evolved much earlier than previously thought.

Researchers unearthed ancient marine fossils containing macroscopic eukaryotes – cells that make up most living organisms today. Previous fossils only showed these cells to have been present 400 million years ago when complex life was thought to have started evolving.

Professor Maoyan Zhu and his team of archaeologists who made the discovery in the Yanshan region of Hebei province in China, found the eukaryotic organisms were large enough to be visible without a microscope which indicates that it was the largest life form on the planet at the time.

“Our discovery pushes back nearly one billion years the appearance of macroscopic, multi-cellular eukaryotes compared to previous research,” said Maoyan Zhu. “This is compelling evidence for the early evolution of organisms large enough to be visible with the naked eye. This totally renews current knowledge on the early history of life.”

The size of these macroscopic eukaryotes is a big deal. At only 11 inches across, they were in fact giant organisms of their time and being present much earlier than first thought shows a period in Earth’s history that was not as dormant as believed.

For billions of years, scientists believe life remained single-celled with no signs of evolving at a quick pace and at some point a moment came when these cells began to develop into multi-celled organisms resulting in the complex life of today. It has perplexed experts as to how and when this happened but the discovery by Zhu and his team show that this occurred at a much earlier stage than they thought with life rapidly flourishing around 550 million years ago.

“The fossils provide the most compelling evidence yet reported that by the beginning of the Mesoproterozoic Era, 1,600 million years ago, eukaryotic organisms had evolved macroscopic form, multicellularity with limited cell differentiation, and probably photosynthesis.”

The findings were published in the journal Nature Communications.