Precambrian

Precambrian is the first Era you will meet in the game, therefore there are no requirements for this era. There are 4 Organisms in this era.

Organisms
After unlocking Spriggina, you will unlock the Technologies.

Trivia

 * This era, Cambrian, and Ordovician are the eras with least organisms, having 4 each.
 * This era spans from 4.6 billion years to 541 million years ago.
 * This era is separated to 3 parts: Hadean(4.6 to 4.0B years ago), Archean (4.0 to 2.5B years ago) and Proterozoic (2.5B to 541M years ago).