Science Weekly: Fossil pushes reset on evolutionary timeline


(Graphic by Brett Ferrin and Autumn Mariano)
(Graphic by Brett Ferrin and Autumn Mariano)

Shuhai Xiao, a geobiologist from Virginia Tech worked with collaborators from the Chinese Academy of Sciences to help determine how, why and when multi-celled organisms evolved from their single-celled ancestors.

The researchers looked at phosphorite rocks from the Doushantuo Formation in South China. Researchers successfully recovered three-dimensionally preserved multicellular fossils that showed cell-to-cell adhesion, differentiation and cell death.

This is all similar to the complexities of eukaryote cells that make up plants and animals. The fossils dated 600 million years ago, 60 million years prior to the appearance of skeletal animals.

The discovery was published in the journal Nature on Sept. 24, 2014, and sets the evolution of life timeline back to 600 million years.

Xiao said this discovery will opens up a new door for researchers to shine some light on the timing and evolutionary steps that were taken by multicellular organisms that would eventually go on to dominate the Earth in a very visible way.

In previous discoveries these fossils have been interpreted as bacteria, single-celled eukaryotes, algae and sponges. This new discovery counteracts those established interpretations.

While some hypotheses have been discredited, some other interpretations, such as multicellular fossils being transitional forms related to animals, are still on the table.

Xiao hopes to reconstruct the complete life cycle of the fossils in the future.

Information compiled from