13 February 2012 - Debate bubbles over the origin of life:
Could life have originated in geothermal ponds? by Brian
Switek
How life began is one of nature’s enduring
mysteries. Fossil and biological clues have led scientists
to estimate that cells originated on this planet about four billion
years ago, but exactly what catalysed their emergence has remained
elusive.
In an 1871 letter to botanist Joseph Hooker, Charles
Darwin wondered whether life might have begun “in some warm little
pond, with all sorts of ammonia and phosphoric salts, light, heat,
electricity, etc. present.” Since then, scientists have
come to conclude that life began in hydrothermal vents in the deep
sea, but a controversial study published this week in Proceedings
of the National Academy of Sciences argues that Darwin might have
been on the right track.
The study, led by Armen Mulkidjanian of Germany’s University of
Osnabrück, suggests that inland pools of condensed and cooled
geothermal vapour have the ideal characteristics for the origin of
life. The conclusion is based mainly on the chemistry of
modern cells. Citing an observation made in 1926 by
biochemist Archibald Macallum that the composition of the cytoplasm
of modern cells differs greatly from that of seawater, and
assuming that cells have changed little over the past four
billion years led the researchers to propose that modern
cell chemistry would provide clues about the type of environment in
which life emerged.
Central to the hypothesis are the ions of particular metals —
the new study is a follow-up to a 2009 paper in which Mulkidjanian
and Michael Galperin suggested that the first cells developed in
zinc-rich environments. “In all living cells,” Mulkidjanian
says,“the cytoplasm is rich in potassium, zinc, manganese, and
phosphate ions, which are not widespread in marine environments,
and has lower amounts of sodium ions than outside.”
Such conditions, the researchers argue, are found only where hot
hydrothermal fluid brings the ions to the surface — places such as
geysers, mud pots, fumeroles and other geothermal features. Within
these fuming and bubbling basins, water laden with zinc and
manganese ions could have collected and cooled in shallow pools
which had drifted away from the geothermal "hot spots" as the
Earth's crust shifted. Such pools could have been amenable
to the development of life. Frustratingly, though, there is very
little likelihood of finding direct evidence of such “hatcheries”,
as Mulkidjanian calls them, in the fossil record.
Mulkidjanian notes that the primordial ponds would have been
extremely acidic and therefore not preserved signs of the first
life. He adds, however, that the ancient conditions could
be modelled in the lab, “so at least some steps of the
proposed scheme could be tested, and we are eager to promote such
experiments and see their results”
The study is already generating strong disagreement among other
early-life experts. Nick Lane, a biochemist at University College
London, UK, points out that the geothermal-pool hypothesis
is problematic both biologically and geologically. “There
was almost certainly very little land 4 billion years ago and
terrestrial systems would have been unstable, short-lived, and
severely limited in distribution,” Lane says.
Such conditions would have made it difficult for early
life to gain a foothold, he says. Lane also notes that the
study has a significant conceptual flaw. “To suggest that the ionic
composition of primordial cells should reflect the composition of
the oceans is to suggest that cells are in equilibrium with their
medium, which is close to saying that they are not alive,” Lane
notes. “Cells require dynamic disequilibrium — that is what being
alive is all about.”
Molecular biologist Jack Szostak of Harvard Medical School in
Cambridge, Massachusetts, says that “geothermal active areas
provide numerous advantages” and are a plausible staging area for
the origin of life, but points out that we can’t be sure
that the chemistry of modern cells reflects the chemical conditions
in which the first cells emerged. He disputes
Mulkidjanian's claim that the high potassium-to-sodium ratio in
modern cells is a sign of deep history, saying that instead, “it
could still be that cells evolved the ability to generate and
maintain a high potassium-to-sodium ratio in their cytoplasm for
functional reasons, independent of the nature of their initial or
early environment.”
So rather than reflecting prehistoric environments,
modern cell chemistry may indicate what sets life
apart.
My comments on the above article follows:
1. The origins of life is always a hotbed of research, debate,
and controversy. The implications arising from this are many. The
two views is only Creation OR evolution. There is no third view.
Either life in the universe was created by a supernatural act of
God or it created itself.
2. Whereas Charles Darwin pondered whether life began in a warm
little pool, it only pushes back the question of origins as to
where the warm little pool comes from, where those chemicals come
from, and how these chemicals could have come together and why. The
genetic code is a piece of information. Information is put together
by intelligence. So who put the information required for life
together?
3. The conclusion of the new study is based on the chemistry of
modern cells which ASSUMED that cells have changed little over 4
billion years. Is this itself a reasonable tenet of evolution? Note
also that it is admitted that there is NO solid evidence of this
so-called warm pools amicable to life. Thus it becomes a matter of
faith....in evolution. And if the conditions can be succesfully
replicated in a laboratory it only proves the point that
intelligence is required for life!
4. The last statement is very revealing. Our study of life only
concludes that a lot sets life apart from nonlife. The best
conclusion, and the only viable one, is that life in the universe
is created, not evolved.
