The Soul Calendar: Are These Fossils The Earliest Traces Of Complex Life?

13 July 2010

Are These Fossils The Earliest Traces Of Complex Life?

*** Check out what was happening on the Earth over two billion years ago as scientists discover new fossils to shed new light on how Life evolved here.

From Denny: Scientists are all a gaggle about some cookie-shaped fossils in the country of Gabon (Africa) that may date as far back as 2.1 billion years. This new find may prove to be the earliest known fossils that represent multicellular life. The Big However is that when you go that far back in Time these kinds of claims can get complicated.

2.1 billion years for multicellular life is one thing. Turns out that microbial life appears to go even farther back into the mists of Time to the tune of 3.45 billion years ago. Scientists base their claims upon the manner in which mats of organic material have been built up in the ancient sediment.

Until now, the science community equivalent of bragging in the Guinness Book of Records, was a 2 billion year old coil-shaped fossil called Grypania spiralis (of course). Size wise it is only centimeter in scale yet may be proved to be a giant form of bacteria or an algae creature.

Scientists know that about at this time of 2.4 billion years ago the Earth's atmosphere went into a transition and increased greatly in oxygen, allowing multicellular creatures to develop. Previous to that time? There appears to have been no oxygen in the air. Ouch! It was a toxic mix of greenhouse gases. It wasn't until about 2.1 billion years ago that there was a little oxygen - but it only made up a tiny percentage compared to today's atmosphere.

"This bacterial world was undergoing the greatest episode of climate change (known as the Great Oxidation Event) in the history of the planet: pumping out oxygen, drawing down carbon dioxide, slowly transforming the Earth into the world we know," according to Donoghue and Antcliff, University of Bristol who wrote commentary on this research.

These newly found fossils exhibit more evidence of structure. They measure as large as 12 centimeters, about 4.7 inches in size. "On the surface, the fossils resemble irregularly shaped cookies with split edges and a lumpy interior," the researchers, led by Abderrarazak El Albani of the University of Poitiers, reported to the media.

El Albani's team collected more than 250 fossils from Gabon. They charted their 3-D structure by placing the fossils through rounds of micro-CT scans. It was from this structure that researchers were able to realize the organisms built up through cell-to-cell signaling. They were not just deposited together as a microbial mat.

What scientists are hoping is for these little fossil cookies to shed some light of how life evolved from this ancient period before the Great Oxidation Event occurred. Yet another tiny piece of the great Life Puzzle and we all know what that means: lots of hard work ahead to fit all the pieces together to make sense of it.

The report was in the journal Nature.

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