On the origin of feces: how animal poo drove Earth’s greatest evolutionary event

In 540 million years ago, a remarkable event known as the Cambrian explosion transformed life on Earth, marking the rapid appearance of most major animal groups and the development of complex marine ecosystems. While scientists have explored various factors driving this diversification, a new research study argues that the evolution of fecal matter played a crucial role in this evolutionary event.

The study, published in Trends in Ecology & Evolution, suggests that the emergence of coprolites, or fossilized feces, coincided with the Cambrian explosion. Fossilized feces, or coprolites, offer a unique window into the past, providing evidence of ancient diets and the ecological processes that shaped the early marine environments.

As animal diversity increased during the Cambrian, so did the production of fecal pellets, which in turn facilitated the redistribution of organic carbon and nutrients through marine ecosystems. The increased fecal matter contributed to a more efficient nutrient cycling process, known as the biological pump, which transported organic matter from surface waters to deeper marine environments.

This ecological feedback loop resulted in more complex marine communities, larger populations, and more intricate food webs. The improved nutrient availability would have supported the colonization of diverse marine habitats, creating a self-reinforcing cycle of growth and complexity.

The study's findings complement other hypotheses explaining the Cambrian explosion, such as oxygenation, evolutionary innovations, and predator-prey interactions. By highlighting the role of fecal matter in driving ecological processes, this research offers a new perspective on the significance of this evolutionary event and its impact on the development of modern marine ecosystems.