This is actually rather promising. It may not be the whole story but
it may well be a key building block. In fact it looks like it may
even be possible to now induce some of the likely steps and slowly
work our way forward. Still a long ways of, but it is certainly a
start.
I have dug around this problem enough to understand that it has to be
naturally self starting. This is starting to look right.
Yet it is also sufficiently intractable that gains will be measured
in decades.
Power behind
primordial soup discovered
by Staff Writers
Leeds UK (SPX) Apr 05, 2013
Researchers at the
University of Leeds may have solved a key puzzle about how objects
from space could have kindled life on Earth. While it is generally
accepted that some important ingredients for life came from
meteorites bombarding the early Earth, scientists have not been able
to explain how that inanimate rock transformed into the building
blocks of life.
This new study shows
how a chemical, similar to one now found in all living cells and
vital for generating the energy that makes something alive, could
have been created when meteorites containing phosphorus minerals
landed in hot, acidic pools of liquids around volcanoes, which were
likely to have been common across the early Earth.
"The mystery of
how living organisms sprung out of lifeless rock has long puzzled
scientists, but we think that 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 between geology
and biology," said Dr Terry Kee, from the University's School of
Chemistry, who led the research.
All life on Earth is
powered by a process called chemiosmosis, where the chemical
adenosine triphosphate (ATP), the rechargeable chemical 'battery' for
life, is both broken down and re-formed during respiration to release
energy used to drive the reactions of life, or metabolism. The
complex enzymes required for both the creation and break down of ATP
are unlikely to have existed on the Earth during the period when life
first developed. This led scientists to look for a more basic
chemical with similar properties to ATP, but that does not require
enzymes to transfer energy.
Phosphorus is the key
element in ATP, and other fundamental building blocks of life like
DNA, but the form it commonly takes on Earth, phosphorus (V), is
largely insoluble in water and has a low chemical reactivity. The
early Earth, however, was regularly bombarded by meteorites and
interstellar dust rich in exotic minerals, including the far more
reactive form of phosphorus, the iron-nickel-phosphorus mineral
schreibersite.
The scientists
simulated the impact of such a meteorite with the hot,
volcanically-active, early Earth by placing samples of the
Sikhote-Alin meteorite, an iron meteorite which fell in Siberia in
1947, in acid taken from the Hveradalur geothermal area in Iceland.
The rock was left to react with the acidic fluid in test tubes
incubated by the surrounding hot spring for four days, followed by a
further 30 days at room temperature.
In their analysis of
the resulting solution the scientists found the compound
pyrophosphite, a molecular 'cousin' of pyrophosphate - the part of
ATP responsible for energy transfer. The scientists believe this
compound could have acted as an earlier form of ATP in what they have
dubbed 'chemical life'.
"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, chemicals 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 Dr Terry Kee.
The team from NASA's
Jet Propulsion Laboratory (JPL-Caltech) working on the Curiosity
rover, which landed on Mars in August last year, has recently
reported the presence of phosphorus on the Red Planet.
"If Curiosity has
found phosphorus in one of the forms we produced in Iceland, this may
indicate that conditions on Mars were at one point suitable for the
development of life in much the same way we now believe it developed
on Earth," added Dr Kee.
The team at Leeds are
now working with colleagues at JPL-Caltech to understand how these
early batteries and the 'chemical life' they became part of might
have developed into biological life. As part of this work they will
be using facilities in the University of Leeds' Faculty of
Engineering, currently used to test new fuel cells, to build a
'geological fuel cell' using minerals and gases common on the early
Earth. Researchers will apply different chemicals to its surface and
monitor the reactions take place and the chemical products which
develop.
The team also hope to
travel to Disko Island in Greenland which is home to the Earth's only
naturally-occurring source of schreibersite, the mineral found in the
Sikhote-Alin meteorite. Here, they hope to repeat their experiments
and show that the same chemicals develop in an entirely
Earth-originated setting.
The paper Hydrothermal
modification of the Sikhote-Alin iron meteorite under low pH
geothermal environments. A plausibly prebiotic route to
activated phosphorus on the early Earth was published online by
the journal Geochimica et Cosmochimica Acta on 15th March 2013. David
E. Bryant, David Greenfield, Richard D. Walshaw, Benjamin R.G.
Johnson, Barry Herschy, Caroline Smith, Matthew A. Pasek, Richard
Telford, Ian Scowen, Tasnim Munshi, Howell G.M. Edwards, Claire R.
Cousins, Ian A. Crawford, Terence P. Kee, Hydrothermal modification
of the Sikhote-Alin iron meteorite under low pH geothermal
environments.
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