Oldest organism discovered
A recent discovery in southern Australia predates the originally-thought commencement of multi-celled organisms on earth, by about 70 million years, making life on earth 650 million years old. Discovered in the Trezona Formation of Flinders Ranges, South Australia, the sponge fossils are especially rare because the organisms were so soft. Scientists must use what they call “chemical fossils” to determine if the tunnels left behind by the sponges were authentic. They did this by testing for steroids, which was produced by the multi-celled The sponges sustained life by filtering sea water through a complex set of organs.
“Molecular clocks, which reflect rates of molecular change in DNA, and biomarker studies of sponge-specific organic compounds both strongly indicate that sponges were present in the Cryogenian interval between approximately 850 and 635 million years ago,” Marc Laflamme says, of Yale University’s Department of Geology and Geophysics.
Scientists say they are not surprised by this discovery, and that it is simply serving as a verification of what they already thought. “The fact that we can detect sponge steranes at all suggests that by the Cryogenian Period [about 850 to 635 million years ago] demosponges were ecologically prominent and there were abundant demosponges living on the shallow sea floor,” said geochemist Gordon D. Love of the University of California, Riverside, who headed up the analysis.
The lead researcher is Gordon D. Love, who is now a professor at the University of California, Riverside. Other authors include Emmanuelle Grosjean a postdoc now at Geoscience Australia; Charlotte Stalvies of the University of Newcastle upon Tyne, U.K.; postdoc David A. Fike and former MIT professor John Grotzinger of Caltech; graduate students Alexander Bradley, Amy Kelly, Maya Bhatia; Bowring and Condon; and William Meredith and Colin Snape of the University of Nottingham, U.K.
The study was funded by Petroleum Development Oman, the NASA Exobiology Program, the NSF EAR program, the Agouron Institute and the NASA Astrobiology Institute.
