Ancient molecules unlock secret of how first animals appeared on Earth

17 Aug 2017

Sample of the extracted molecules that have led to this latest groundbreaking discovery. Image: ANU

By analysing samples of ancient molecules, researchers believe they have solved the mystery of how the first animals appeared on Earth.

The appearance of the first animals on Earth was a pivotal moment in our planet’s history, but from time immemorial, their origin has remained a complete mystery.

Now, however, new research published by a team from the Australian National University (ANU) appears to pinpoint the reason in what it is calling a groundbreaking discovery, quite literally.

Future Human

In a paper published to Nature, the team led by Prof Jochen Brocks revealed that it began by crushing ancient sedimentary rocks found in central Australia, and extracting the ancient molecules of organisms found within them.

Dated to around 650m years ago, the molecules showed that this period saw the rise of algae, which triggered the most profound ecological revolutions in Earth’s history.

“Before all of this happened, there was a dramatic event 50m years earlier called ‘Snowball Earth’,” Brocks said.

“Huge glaciers ground entire mountain ranges to powder that released nutrients and, when the snow melted during an extreme global heating event, rivers washed torrents of nutrients into the ocean.”

The burst of energy for evolution

With high levels of nutrients in the oceans that were rapidly cooling as a result of the melting ice, the perfect conditions were created for the rapid spread of algae.

“These large and nutritious organisms at the base of the food web provided the burst of energy required for the evolution of complex ecosystems, where increasingly large and complex animals, including humans, could thrive on Earth,” Brocks added.

This isn’t the first time that Australia has unearthed secrets about our ancient past as, just last month, an international team of researchers revealed an incredible find on the continent, suggesting that the first humans arrived there around 10,000 years earlier than was previously thought.

In a paper published to Nature, the researchers said they dated artefacts in Madjedbebe, Northern Australia to 65,000 years ago, despite previous theories suggesting anywhere between 47,000 and 60,000 years.

Colm Gorey was a senior journalist with Silicon Republic