Ancient animal waste may have helped fuel the development and diversification of early marine ecosystems. Tiny pellets of fossilized waste may preserve evidence of a major transformation in early animal life. An international study led by Flinders University proposes that excrement helped reshape ancient oceans during one of evolution’s most important turning points. Their analysis suggests that growing quantities of animal waste redistributed organic matter and nutrients, helping marine ecosystems become more complex. Primitive sea animals deposited fossilized pellets known as ‘coprolites’ throughout early Cambrian environments.