Re: David Deamer's Ideas
- From: Tom Hendricks <tom-hendricks@xxxxxxx>
- Date: Sun, 2 Mar 2008 14:09:11 -0500 (EST)
On Feb 29, 12:41 pm, "Perplexed in Peoria" <jimmene...@xxxxxxxxxxxxx>
wrote:
"Tom Hendricks" <tom-hendri...@xxxxxxx> wrote in messagenews:fq6vn6$6ng$1@xxxxxxxxxxxxxxxxxxxxxx
On Feb 27, 12:24 am, "Perplexed in Peoria" <jimmene...@xxxxxxxxxxxxx>
wrote:
"Tom Hendricks" <tom-hendri...@xxxxxxx> wrote in messagenews:fq1mmj$5im$1@xxxxxxxxxxxxxxxxxxxxxx
These excerpts from an article on David Deamer.
UCSC chemist explores the membranous origins of the first living cell
"Membranous boundary structures define all life today," he said. "A
source of membrane-bounded microenvironments on the early Earth was
essential for the rise of cellular life."
Deamer has been investigating the origins of life for more than 20
years, with continuous funding from NASA's Exobiology and Astrobiology
Programs. In the 1980s, he demonstrated that meteorites contain
molecules capable of forming stable membranes. More recently, he has
ventured from the laboratory into the field to test ideas about the
kind of environment where life could have begun....
In June 2005, he led a team of scientists, including Russian geologist
Vladimir Kompanichenko, to the Kamchatka region in eastern Russia, an
area abounding in pools of water heated and sterilized by constant
volcanic activity. Deamer carried with him a version of the
"primordial soup"--a mixture of compounds like those a meteorite could
have delivered to the early Earth, including a fatty acid, amino
acids, phosphate, glycerol, and the building blocks of nucleic acids.
Finding a promising-looking boiling pool on the flanks of an active
volcano, he poured the mixture in and then took samples from the pool
at various intervals for analysis back in the lab at UCSC.
The results were strikingly negative: life did not emerge, no
membranes assembled themselves, and no amino acids combined into
proteins. Instead, the added chemicals quickly vanished, mostly
absorbed by clay particles in the pool. Instead of supporting life,
the bubbling pool had snuffed it out before it began. Later, Deamer
repeated the same experiment at Lassen Volcanic National Park in
northern California, with the same negative result.
What went wrong? The explanation is simple, said Deamer, who presented
his findings in February at a meeting of the Royal Society of London.
Conditions in geothermal springs and similar extreme environments just
do not favor membrane formation, which is inhibited or disrupted by
acidity, dissolved salts, high temperatures, and calcium, iron, and
magnesium ions. Furthermore, mineral surfaces in these clay-lined
pools tend to remove phosphates and organic chemicals from the
solution.
"We have to face up to the biophysical facts of life," Deamer said.
"Hot, acidic hydrothermal systems are not conducive to self-assembly
processes. But these results serve to guide us to other possible sites
that might be better choices...."
This sounds to me like another blast against the ventists.
Sounds that way to me too. Deamer is a bit of an odd-man-out from
my viewpoint. He understands the importance of lipids and membranes.
But he (rather absurdly, IMHO) is a confirmed believer in a heterotrophic
origin, and one fed by extraterrestrial sources to boot. Very weird.
Unfortunately, Deamer is another one with a pop and adapt scenario:
First magic chemistry pops out of nothing. then protected in vesicles
they are safe to adapt.
But the magic chemistry is fluke chemistry, and the 'safe to adapt' is
another fluke. Again we have a pop and adapt theory, with fluke
squared chance of happening.
Tom, I really wish you would try to understand what other people are
saying, rather than seeking the rhetoric to mock it. But then I really
wish politicians would do that too. And they don't follow my wishes
either.
[snip]
But science ideas need to stand up to tough scrutiny. If they are on
the wrong road, then challenging them helps them. Correct scenarios
will stand up to challenges.
There is no such thing as an intellectual chaqllenge from someone who
doesn't understand what he is challenging.
Looking for a chemical fluke or series of chemical flukes is the
mistake that has caused
all OOL scenarios to be stuck. And if Deamer has real proof, I'll be
the first to congratulate him. But if he's another standing in the way of
a real solution, then I'll point out my concerns.
..
We could get through the OOL impasse if we see life as a reflection of
the environment not a magic event popping out of it.
And that is a perfect example of your lack of understanding and your
preference for being a nuisance over being an honest critic. As you
know perfectly well, no one is advocating the position that there
was a "magic event". So what makes you think that it is 'tough
scrutiny' to pretend that other people are talking about magic events.
How, exactly, does a scenario benefit from this 'challenge'.
Not true. Those that say replicator came first - that's there magical
event.
those that say metabolism came first - that is there magical event
those that say clay came first - that is there magical event
those that say RNA world came first - that is there magical event.
those that say the membrane came first - that is there magical event.
I say nothing came first. There was no origin, no magic moment in time
that life was after, but not before.
And inherent in all these scenarios is a 'we are life, we are better than
the low class environment around us - we are outside the environment
cause we are so special." Don't you see that too?
Nope. Don't see that at all. What I do see is an honest attempt to
discover just what are the diagnostic features ('special features' if you
prefer) of life. Some people - including you, I notice - seem to think
that defining life helps to guide the search for its origin.
Whatever toughness I bring to the discussion just helps IMO.
NOT!!! IMnsHO
.
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