Sentences with phrase «microbial life starting»
Scientists have discovered a rich fossil record of animal evolution going back more than 600 million years and a much richer one of microbial life starting almost 4 billion years ago.
http://www.hhmi.org/ Not exact matches
Oxygen seems an obvious place to start, but we know Earth hosted microbial life when it had no detectable oxygen in its atmosphere during the Archaean period — 4 to 2.5 billion years ago.