Evolution By efakjisrjfos 45,000 BCE primordial soup (creation of life before everything else) 35,000 BCE The oldest known fossils are prokaryotic (3.5 billion years old) 20,000 BCE The oldest unicellular eukaryotic fossils (2 billion years old) 16,000 BCE The oldest multicellular eukaryotic fossils(1.6 billion years old) 540 BCE The oldest known animal fossils (570-540 million years old) Jan 1, 1953 The creation of the Primordial soup theory Jan 1, 1980 discovery of ribozymes