Geological period since the formation of our planet (about 4 600 million years ago) until the beginning of the palaeozoic period about 570 million years ago.

The duration of this very long period is not shown true to scale by the figure. During the precambrian period the first continents formed and the first larger organisms developed (like the simple marine worm shown by the figure). Because these organisms did not form stable skeletons, almost no fossils from this period remained.