Earth's first ecosystems were more complex than previously thought, study finds

November 27, 2015, University of Bristol
Computer simulations have allowed scientists, led by Dr Imran Rahman of the University of Bristol, UK to work out how this 555-million-year-old organism with no known modern relatives fed. Their research reveals that some of the first large, complex organisms on Earth formed ecosystems that were much more complex than previously thought. Credit: M. Laflamme

Computer simulations have allowed scientists to work out how a puzzling 555-million-year-old organism with no known modern relatives fed, revealing that some of the first large, complex organisms on Earth formed ecosystems that were much more complex than previously thought.

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, , 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.

Dr Simon Darroch, an Assistant Professor at Vanderbilt University, said: "For many years, scientists have assumed that Earth's oldest complex organisms, which lived over half a billion years ago, fed in only one or two different ways. Our study has shown this to be untrue, Tribrachidium and perhaps other species were capable of suspension feeding. This demonstrates that, contrary to our expectations, some of the first ecosystems were actually quite complex."

Co-author Dr Marc Laflamme, an Assistant Professor at the University of Toronto Mississauga, added: "Tribrachidium doesn't look like any modern species, and so it has been really hard to work out what it was like when it was alive. The application of cutting-edge techniques, such as CT scanning and , allowed us to determine, for the first time, how this long-extinct organism fed."

Such simulations have allowed scientists, led by Dr Imran Rahman of the University of Bristol, UK to work out how this 555-million-year-old organism with no known modern relatives fed. Their research reveals that some of the first large, complex organisms on Earth formed ecosystems that were much more complex than previously thought. Credit: I.A. Rahman

Computational is a method for simulating fluid flows that is commonly used in engineering, for example in aircraft design, but this is one of the first applications of the technique in palaeontology (following up previous research carried out at Bristol).

Dr Rahman, a Research Fellow in Bristol's School of Earth Sciences said: "The computer simulations we ran allowed us to test competing theories for feeding in Tribrachidium. This approach has great potential for improving our understanding of many ."

Co-author Dr Rachel Racicot, a postdoctoral researcher at the Natural History Museum of Los Angeles County added: "Methods for digitally analysing fossils in 3D have become increasingly widespread and accessible over the last 20 years. We can now use these data to address any number of questions about the biology and ecology of ancient and modern organisms."

The study is published today in the journal Science Advances.

Explore further: Computer simulations reveal feeding in early animal

More information: 'Suspension feeding in the enigmatic Ediacaran organism Tribrachidium demonstrates complexity of Neoproterozoic ecosystems' by Imran A. Rahman, Simon A. F. Darroch, Rachel A. Racicot and Marc Laflamme in Science Advances, DOI: 10.1126/sciadv.1500800

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1 / 5 (9) Nov 27, 2015
The most impressive organisms not mentioned by today's "bought" pseudo-scientists are cyanobacteria. These photosynthetic marvels ALONE turned earth's early poisonous atmosphere into what it is today. They paved the way for plant life. And then came more complex life forms.

The ability of this photosynthetic organism to dramatically change the earth's early atmosphere without the aid of plants reveals how powerful an influence they had and can still have. The good news is this: Even if we destroy most of our rain forests and pump loads of CO2 into the atmosphere, this organism ALONE can handle it and keep our atmosphere in balance. Doing so is a far easier task than taming a poisonous atmosphere. More CO2 means more cyanobacteria, means more oxygen, means more interaction with excessive methane. Every educated, HONEST climatologist should know this. Why the silence? Are they all in the pockets of corrupt politicians?
5 / 5 (5) Nov 28, 2015
Ediacaran suspension feeding! Cool.

@Freethinker: [confused drivel that can't be responded to, does he/she discuss pseudosciences as claimed initially or sciences as mentioned later? And what has an earlier biosphere to do with today's *climate*!?

Except of course the obvious response that man made CO2 increase is *observed* to be the current climate driver - *in the current biosphere* - with 99.999 % certainty: https://theconver...y-29911, which 99.99 % of scientists agree on: http://www.jamesp...dex.html ]
5 / 5 (3) Nov 28, 2015
Freethinker51, no, a world full of scientists all in the pocket of politicians pushing a specific side of a political controversy is not a plausible explanation. Such a conspiracy would be ludicrous. The numbers of politicians disagreeing with scientist's findings may even be weighted in favor of your opinions in some countries.

A more likely scenario would be that HONEST scientists don't work backwards from a conclusion (every things gonna be alright). They don't cherry pick simplified principals that, on the surface, seem to support their conclusion while ignoring other principals (like time scales involved) that falsify their beliefs. If they tried it, even once, they would be called out by their peers around the world.

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