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 ...

The Precambrian encompasses 86 percent of the history of Earth. As its name implies, this includes all of geological time prior to the Cambrian period. Hadean Era (4,550-3,850 mya) The Precambrian ...

A lot has happened in that time. Earth formed and oxygen levels rose in the foundational years of the Precambrian. The productive Paleozoic era gave rise to hard-shelled organisms, vertebrates ...

Geologists have found that an ancient meteorite hit Scotland 200 million years later than previously thought, which has ...

the supercontinents of Gondwana 2 and Nuna (Columbia), as well as the geology of the Precambrian era. Earth scientists in the department also closely monitor global issues, such as energy security.

More extensive Precambrian finds ... that skeletonized creatures of the Cambrian period, long thought by scientists to be the first multicellular animals, had predecessors. Debate continues ...