Watch for Falling Amino Acids
A long-standing problem of origin-of-life theories is how proteins became left-handed. Amino acids, the building blocks of proteins, come in right-handed and left-handed forms, yet life uses only the left-handed form.
The two isoforms are otherwise identical—yet one amino acid of the wrong hand in a protein spells doom for its function. Wherever amino acids form naturally (as in Stanley Miller’s spark-discharge experiment), they form in roughly equal amounts of both hands (racemic mixture). How could a natural system isolate and purify the mixture without the DNA code and ribosomes that ensure quality control in life? One new suggestion printed in Science Daily was adorned with a picture of a ribosome and the suggestive title, “Meteorites Delivered The ‘Seeds’ Of Earth’s Left-hand Life.” The first paragraph almost sounds like the beginning of a children’s story:
Flash back three or four billion years — Earth is a hot, dry and lifeless place. All is still. Without warning, a meteor slams into the desert plains at over ten thousand miles per hour. With it, this violent collision may have planted the chemical seeds of life on Earth.
These “seeds” (amino acids) would have had a tough time without fertilizer landing in a desert of rock and sand, since fertilizer comes from living organisms. Amino acids are not that hard to manufacture in natural conditions. Only a large stretch of imagination could consider them to be seeds. The story continues with the metaphor switching from farming to cooking.
Scientists have presented evidence that desert heat, a little water, and meteorite impacts may have been enough to cook up one of the first prerequisites for life: The dominance of “left-handed” amino acids, the building blocks of life on this planet.
The article reports on research by scientists from Columbia University and the American Chemical Society. Till now, simulations of early-earth conditions and chemical models have only been able to produce a slight excess of one hand over the other (06/21/2004, 11/19/2004, 11/05/2004, 12/03/2004, 03/23/2005). Another problem is keeping them one-handed (09/26/2002). The scientists first proposed that meteorites accumulate a 5-10% excess of one hand from circularly polarized light from neutron stars. Landing on earth, the excess becomes amplified through repeated episodes of wetting and drying.
Thus the desert: this would not work in an oceanic “primordial soup.” The meteor has to deliver its goods on dry ground, then be close enough to the ocean to reach “a little bit of water.” These are called “plausible prebiotic conditions.” It is hard to believe, however, that sufficient quantities of amino acids could have been delivered to one location on a large planet. Also, the wetting process tends to dissolve the polypeptides; they only crystallize during the drying period. Even if a long chain of one-handed amino acids did crystallize, it would be the end of the line unless incorporated with RNA or DNA into a system. In life, both depend on each other.
The press release is filled with optimism. Ronald Breslow (Columbia) added humor to the imaginary scenario:
“These meteorites were bringing in what I call the ‘seeds of chirality,’” stated Breslow. “If you have a universe that was just the mirror image of the one we know about, then in fact, presumably it would have right-handed amino acids. That’s why I’m only half kidding when I say there is a guy on the other side of the universe with his heart on the right hand side.”
A check of the far side of the universe is not necessary. Presumably Titan, Enceladus or Europa could have gotten its shipment in right-handed amino acids, since it is a matter of chance according to naturalistic theories. That is why astrobiologists consider finding right-handed polypeptides a biomarker.
The goal is 100% purity of one hand over the other. Living things enforce 100% purity through multiple quality-control mechanisms. It was not clear from the article how much of an excess was actually achieved experimentally. The report seemed to leap to the conclusion that amplification by wetting and drying cycles would achieve the necessary purity:
Breslow found that the left and right-handed amino acids would bind together as they crystallized from water. The left-right bound amino acids left the solution as water evaporated, leaving behind increasing amounts of the left-amino acid in solution. Eventually, the amino acid in excess became ubiquitous as it was used selectively by living organisms.
That last sentence, though, implies the existence of the DNA code and ribosomes. How a pre-genetic system could tell the difference, or care, was left unexplained.
This story is far-fetched to the extreme. Anyone familiar with the problem must stand aghast at the leaps of faith required to believe in their fairy tale. For a refresher on the severity of this problem, read our online book, chapter 3 and chapter 4.
They get away with it because their worldview requires it, and they have nothing else. Dressing it up with humor and metaphor doesn’t distract the wise.
Shame on science reporters for portraying fairy tales as science. Dave Mosher, who trashed the ID movie Expelled yesterday (see 04/07/2008), had no problem with the pseudoscience in this paper. In fact, he even embellished it more in his LiveScience article that was syndicated to Yahoo.com and other news outlets: “Neutron starlight might have zapped amino acids riding on comets and asteroids into a bias, and a little water might have concentrated them after they crashed into Earth, a team of scientists now say.” So Mr. Mosher thinks he knows science well enough to demonize all the PhDs in the movie Expelled, but cannot see the demons of irrationality and imagination channeling through evolution-worshiping scientists.
That’s why one of our readers, a retired engineer, called the guilty website “Sèance Daily” (also works for Live Sèance). He wrote up a spoof that has more believable science in it than the article above:
Meteorites Delivered The ‘Seeds’ Of Earth’s Chain Link Fences, Experts Argue
Sèance Daily (Apr. 6, 2008): Flash back three or four billion years — Earth is a hot, dry and fence-less place. All is still. Without warning, a meteor slams into the desert plains at over ten thousand miles per hour. With it, this violent collision may have planted the chemical seeds of chain-link fences on Earth.
Scientists have presented evidence that desert heat, a little hand waving, and meteorite impacts may have been enough to cook up one of the first prerequisites for aluminum fences: The dominance of “left-handed” aluminum atoms, the building blocks of chain-linked fences on this planet.
In a report at the 235th national meeting of the Atheist Apologist Society, Donald Slowbres, B.S., University Professor, Darwin University, and former AAS Official Watchmaker Debunker, described how aluminum fences came from outer space.
Chains of aluminum atoms make up the strands found in fences, various rods, and all cheap sets of pots and pans. There are two orientations of aluminum atoms, left and right, which mirror each other in the same way your hands do. This is known as “chirality.” In order for chain-linked fences to arise, fences must contain only one chiral form of aluminum atoms, left or right, Slowbres noted.
“If you mix up chirality, a fence’s properties change enormously. Chain-linked fences couldn’t operate with just random mixtures of stuff,” he said….
… Evidence of this left-handed excess was found on the surfaces of these meteorites, which have crashed into Earth even within the last hundred years, landing in Disney’s Fantasy Land Theme Park.
Slowbres simulated what occurred after the dust settled following a meteor bombardment, when the aluminum atoms on the meteor mixed with the primadona soup. Under “credible pre-fencetic conditions”– desert-like temperatures and a little bit of random mutation — he exposed aluminum atom chemical precursors to those aluminum atoms found on meteorites.
Slowbres and Darwin chemistry grad student Quickdraw McDuck found that these cosmic aluminum atoms could directly transfer their chirality to simple aluminum atoms found in aluminum fences. Thus far, Slowbres’s team is the first to demonstrate that this kind of handedness transfer is possible under these conditions.
On pre-fence Earth, this transfer left a slight excess of left-handed aluminum atoms, Slowbres said. His next experiments with beer cans replicated the chemistry that led to the amplification and eventual dominance of left-handed aluminum atoms.
The steps afterward that led towards the genesis of chain-linked fences are shrouded in mystery. Slowbres hopes to shine more light on pre-fence Earth as he turns his attention to iron atoms, the chemical units of the Eiffel Tower and its more primitive cousin, the Eiffel Fence.
“This work is related to the probability that there is chain-linked fences somewhere else,” said Slowbres. “Everything that is going on on Earth occurred because the meteorites happened to land here. But they are obviously landing in other places. If there is another planet that has the cow pastures and all of the things that cows excrete, you should be able to get the same process rolling.”