Eos, Transactions American Geophysical Union

Oldest life-forms may have made own food

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Abstract

The oldest organisms yet discovered were probably far enough advanced along the evolutionary scale to have made their own sources of food energy, perhaps much like present-day plants, according to one of the members of the team that studied the Australian microfossils. If so, the time of origin of life may have to be set substantially earlier than the 3.5-billion-year-old fossils in order to account for simpler precursororganisms.

Mass spectroscopic analysis of organic carbon from rocks that contain fossils of the bacteria-like microorganisms, discovered in the Warrawoona group of western Australia, revealed the same ratio of carbon 13 to carbon 12 that is characteristic of today's living organisms, Indiana University researcher John Hayes said. Hayes, along with doctoral student Kim W. Wedeking, conducted the analysis.

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