Early ecosystems were more complex than previously believed

An organism from 555 million years ago has shown that Earth's first ecosystems were more complex than previously believed.

Computer simulations have allowed scientists to work out how the puzzling organism with no known modern relatives fed, revealing that some of the first large, complex organisms on Earth formed ecosystems that were very complex.

The international team of researchers from Canada, the UK and the USA, including Dr Imran Rahman from the University of Bristol, UK studied fossils of an extinct organism called Tribrachidium, which lived in the oceans some 555 million years ago.

Using a computer modelling approach called computational fluid dynamics, they were able to show that Tribrachidium fed by collecting particles suspended in water. This is called suspension feeding and it had not previously been documented in organisms from this period of time.

Tribrachidium lived during a period of time called the Ediacaran, which ranged from 635 million to 541 million years ago. This period was characterised by a variety of large, complex organisms, most of which are difficult to link to any modern species.

It was previously thought that these organisms formed simple ecosystems characterised by only a few feeding modes, but the new study suggests they were capable of more types of feeding than previously appreciated.

Simon Darroch from Vanderbilt University said that the study demonstrates that, contrary to the expectations, some of the first ecosystems were actually quite complex.

The study appears in Science Advances.