Ancient ‘seaweed’ fossils offer fresh look at life on earth

A fresh look at fossils of the oldest known complex life form, found near Beijing more than two decades ago, could rewrite the history of evolution, according to a new study led by Chinese scientists.

The “eukaryote” organisms lived in shallow seawater more than 1.5 billion years ago and could grow to the length of a foot and the width of a palm. They looked like seaweed and probably carried out photosynthesis, researchers said.

The 160 specimens had stayed in the home of their discoverer, retired Tianjin geologist Zhu Shi­xing, for more than two decades but were re-examined by an international team with new technology. The results were published in the journal Nature Communications on Tuesday.

“The fossils remained in drawers because nobody believed that life could grow so big in a period so early. It completely toppled our understanding of the early history of life,” said Professor Zhu Mao­yan, the team’s lead scientist at the Chinese Academy of Sciences’ Nanjing Institute of Geology and Palaeontology in Jiangsu province.

Phil Donoghue, a professor of palaeobiology at the University of Bristol in Britain told Agence France-Presse the discovery was a “big deal”. “They are not the oldest eukaryotes, but they are certainly the oldest demonstrably multicellular eukaryotes.”

The researchers said the discovery advanced the rise of complex life forms by nearly one billion years. Back then, volcanic eruptions, a toxic atmosphere and the near-absence of oxygen prevented life from evolving into large and sophisticated forms. Though the earliest life appeared as early as four billion years ago, researchers thought life remained single-celled until 600 million years ago.

Zhu said the Chinese fossils, discovered in the Yanshan area in Hebei province, suggested a possible “Eden” for life on earth 1.56 billion years ago.