----- Original Message -----
From: "Allan Harvey" <aharvey@boulder.nist.gov>
Sent: Thursday, April 27, 2000 2:58 PM
> That does bring up a related question I have wondered about. I get the
> impression that the biochemistry of animal life is tuned to a fairly
narrow
> range of temperatures -- make things hotter by 20 K or so (don't hold me
to
> that number) and enzymes and proteins break down, make things colder by 20
> K and reactions don't go fast enough. To what extent is that temperature
> range a fundamental constraint, or is it conceivable that our biochemistry
> could work (just with slightly different enzymes, etc.) at substantially
> different temperatures? If we still could have evolved if liquid water
was
> 50 K hotter or 50 K colder, then I think the anthropic argument on water's
> dipole moment pretty much vanishes.
The answer to your question is yes life can live at very hot temperatures.
There are those who now think life first evolved underground, at the ridge
vents in the bottom of the ocean. Why? Some of the oldest microbes are
thermophiles. Here is what Paul Davies says:
"Shock finds that the available energy is maximized at around 100-150
degrees Celsius, precisely the temperature range in which hyperthermophiles
live. Not only can these organisms readily tap into the vast reserves of
chemical and thermal energy provided, they can even gain energy by
fabricating simple organic compounds. The energy released may then be used
to pay for thermodynamically unfavorable reactions like peptide synthesis.
Shock estimates that in a typical vent life can exploit this thermodynamic
bonanza by creating biomass at the prodigious rate of two and a half
kilograms per hour." Paul Davies, The Fifth Miracle, (New York: Simon and
Schuster, 1999), p. 174
"When hyperthermophiles were first discovered, most microbiologists were
inclined to dismiss them as aberrations-weird organisms that must have
somehow invaded peculiar high-temperature evidence points to the opposite
conclusion: the earliest micro-organisms were all hyperthermophiles, and
only later did some adapt to life at lower temperatures. In certain
locations beneath the Earth's surface, pockets remain where conditions
resemble those of very long ago." Paul Davies, The Fifth Miracle, (New York:
Simon and Schuster, 1999), p. 177
"The theory that life began hot and deep was first mooted in 1981 by Jack
Corliss of the University of Maryland, and popularized by Tommy Gold in a
trail-blazing paper published in 1992." Paul Davies, The Fifth Miracle, (New
York: Simon and Schuster, 1999), p. 177-178
"Phylogenetic trees of life typically reveal that the extant
hyperthermophilic bacteria and archaeal species, which inhabit environments
of extreme temeperatures, have some of the deepest and oldest branches, and
it is consequently a widely endorsed textbook view that the common ancestor
of life was adapted to hot conditions.
"The proportion of all nucleotides that are either guanine or cytosine (the
G+C content) of ribosomal RNA is a reliable indicator of the environmental
temperature of an organism, so an estimate of the G+C content of the root of
the tree of life provides evidence for the environmental conditions that
prevailed when the common ancestor to life arose." Mark Pagel, "Inferring
the Historical Patterns of Biological Evolution," Nature, 401(1999):877-884,
p.879
"The official temperature record is currently held by an organism known as
Pyrodictium occultum that reportedly emerged fit and well after autoclaving
at temperatures of 121 degrees Celsius for an hour. However, John Parkes of
Bristol University claims to have evidence of microbes living at
temperatures as high as 169 degrees Celsius." Paul Davies, The Fifth
Miracle, (New York: Simon and Schuster, 1999), p. 167
glenn
Foundation, Fall and Flood
Adam, Apes and Anthropology
http://www.flash.net/~mortongr/dmd.htm
Lots of information on creation/evolution
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