Some half a billion years ago, life on Earth went through a huge transformation. In what is called the Ediacaran period, after billions of years of single-celled organisms, large multicellular organisms emerged in the fossil record.
These traces of the oldest complex ecosystems have been found in only a handful of locations around the world. The fossils were made by soft-bodied creatures covered by sand, creating impressions of their squashed remains imprinted into rock.
