Primordial soup secret revealed
10 May 2013 by Evoluted New Media
Scientists may have cracked a common conundrum about how objects from space could have kindled life on Earth.
The study, led by Leeds University, revealed how a chemical, similar to one now found in all living cells, could have been created when phosphorus-containing meteorites landed in hot, acidic pools of liquid around volcanoes that were likely present across the early Earth.
“The mystery of how living organisms sprung out of lifeless rock has long puzzled scientists, but we think the unusual phosphorus chemicals we found could be a precursor to the batteries that now power all life on Earth. But the fact that it developed simply, in conditions similar to the early Earth, suggests this could be the missing link between geology and biology,” said Dr Terry Kee, from the University’s School of Chemistry, who led the research.
Life on Earth is powered by chemiosmosis, where adenosine triphosphate (ATP) is broken down and re-formed during respiration to release the energy that drives metabolism.
Phosphorus is the key element in ATP and the form it commonly takes on Earth is largely insoluble in water with low chemical reactivity. But the early Earth was regularly bombarded by meteorites and interstellar dust rich in exotic materials such as the more reactive form of phosphorus, the iron-nickel-phosphorus mineral schreibersite.
The researchers place samples of Sikhote-Alin meteorite, which fell in Siberia in 1947, in acid taken from the Hveradalur geothermal area in Iceland. They left the rock to react with the acid in test tubes incubated by the surrounding hot spring for four days, followed by a further 30 days at room temperature.
The resulting solution contained pyrophosphite, a molecular ‘cousin’ of pyrophosphate - the part of ATP responsible for energy transfer. The authors of the work published in Geochimica et Cosmochimica Acta, speculate this compound could have acted as an earlier form of ATP.
“Chemical life would have been the intermediary step between inorganic rock and the very first living biological cell. You could think of chemical life as a machine – a robot, for example, is capable of moving and reacting to surroundings, but it is not alive. With the aid of these primitive batteries, chemical became organised in such a way as to be capable of more complex behaviour and would have eventually developed into the living biological structures we see today,” said Kee.
