Scientists have found what they believe is evidence for the oldest life on Earth yet discovered. Dr Minik Rosing and colleagues at the Geologisk Museum in Copenhagen tested for the chemical signature of plankton in rocks recovered in west Greenland which date back 3.7 billion years. There were no standard fossils recovered but they did find what they suspect is the plankton's chemical residues.
They were examining microscopic globules of graphite, pure carbon, taken from metamorphic rocks known to be 3.7 billion years old and known to have once been seafloor sediment.