Animal ancestors may have survived ‘snowball Earth’

Chemical fossils push back the date for animal life to at least 635 million years ago

By Rachel Ehrenberg, 13:58 PM February 4, 2009

A new analysis of ancient chemical fossils has rocked the cradle of early animal evolution, bumping back compelling evidence of animal life to at least 635 million years ago.

The findings, published in the Feb. 5 Nature, suggest that the ancient ancestor of fully formed animals survived a massive glaciation that enshrouded the Earth in ice at the end of the aptly named Cryogenian period. Debate continues over how much of the planet was frozen during two ice ages, each possibly a “snowball ...

Source URL:‘snowball-earth’