Although life was beginning to appear during the latter part of the Precambrian Era, the first fossil record is from the Burgess shale deposits in Yoho National Park. Wonderful Life by Stephen Jay Gould is a bestseller description of this time.

The four main Eras of Earth history may also be labeled by their dominant life form.

Era mya life Precambrian 2.5 b - 570 m unicelled Paleozoic 570 m - 225 m fishes Mesozoic 225 m - 65 m dinosaurs Cenozoic 65 m - present mammals

Human history begins about 7 million years ago.