Food for Early Animal Evolution

Abstract

Ever since microorganisms first emerged, Earth and the life upon it have engaged in something of a pas de deux. Seldom during this long history have the dance's tempo and the dramatic heights of the jeté leaps exceeded those that occurred near the end of the Proterozoic eon, which spanned the time from 2.5 billion to 541 million years ago. A supercontinent broke apart and then began to reassemble; ice ages twice whitened the planet from pole to Equator; and redox conditions underwent a fundamental shift.