A pink sponge, photographed at an aquarium today, is not unlike one of the first life forms that appeared in the Precambrian era. Photograph by Joel Sartore, National Geographic Photo Ark The ...

A team of researchers has identified the earliest known ecdysozoan fossil, which originated from the Precambrian era.

Hadean Era (4,550-3,850 mya) The Precambrian's oldest era ... asteroids -- forms from interstellar gas and dust. Prelude to life (4,550-3,900 mya) Planet Earth is very hot at its formation.

During the Proterozoic era, oxygen produced by photosynthesizing ... suggest complex multicellular life evolved as far back as 900 mya. More extensive Precambrian finds, particularly those ...