caravelair

i have a creationist claiming that amino acids could not have formed under the conditions of the early earth. i have heard that lab experiments have been done where these conditions were replicated and amino acids did indeed form. does anyone know of any scientific articles i can refer him to?

Doubting Didymus

Naturally. You'll no doubt soon be bombarded with miller-urey papers. I have made a quick search and found a nice, easy to read (just the way I like 'em), article from some universitys chemistry faculty that explains the experiment and related experiments as well as their results. You not only get amino acids from these fellers, you also get adenine, one of the most important nucleotide bases.

The Miller/Urey experiment

Coragyps

And from places like the Murchison and Tagish Lake metoerites, you get a wide variety of amino acids, fatty acids, and other swell things like the vitamin niacin (= pyridine-3-carboxylic acid), all from hydrogen cyanide gas and the like plus some ultraviolet light, and finally just add water. One link is here , though you must register (free) to read the paper.

Dr.GH

There is a High School level Miller/Urey page too:

http://www.accessexcellence.org/WN/NM/miller.html


Some extraterrestrial amino acid sources:

BERNSTEIN, M. P., J. P. DWORKIN, S. A. SANDFORD, G. W. COOPER & L. J. ALLAMANDOLA
2002 Racemic amino acids from the ultraviolet photolysis of interstellar ice analogues. Nature 416, 401 - 403 (2002)

Dreibus, G., H. Wanke, G. W. Lugmair
1997 “Volitile Inventories of Mars and Earth and Their Implication for the Evolution of the Planetary Atmospheres” Workshop on Early Mars (1997)

Dworkin, Jason P., David W. Deamer, Scott A. Sandford, and Louis J. Allamandola
2000 “Self-assembling amphiphilic molecules: Synthesis in simulated interstellar/precometary ices” PNAS 98: 815-819

and,

Abiotic generation of complex molecules on the Archean Earth

Abiotic amino acids

Amend, J. P. , E. L. Shock
1998 “Energetics of Amino Acid Synthesis in Hydrothermal Ecosystems” Volume 281, number 5383, Issue of 11 Sep , pp. 1659-1662.

Blochl, Elisabeth, Martin Keller, Gunter Wachtershauser, Karl Otto Stetter
1992 “Reactions depending on iron sulfide and linking geochemistry with biochemistry” PNAS-USA v.89: 8117-8120

BRANDES, JAY A., NABIL Z. BOCTOR, GEORGE D. CODY, BENJAMIN A. COOPER, ROBERT M. HAZEN & HATTEN S. YODER JR
1998 Abiotic nitrogen reduction on the early Earth Nature 395, 365 - 367

Horita, Juske, Michael E. Berndt
1999 Abiogenic Methane Formation and Isotropic Fractionization Under Hydrothermal Conditions. Science 285 (5430): 1055

Lazcano, Antonio, Stanley L. Miller
1996 “The Origin and Early Evolution of Life: Prebiotic Chemistry, the Pre-RNA World, and Time” Cell vol 85:793-798

Lazcano, A. & S.L. Miller
1994 How long did it take for life to begin and evolve to cyanobacteria Journal of Molecular Evolution 39(6): 546-554, December
Lollar, B. Sherwood, T. D. Westgate, J. A. Ward, G. F. Slater & G. Lacrampe-Coulloume
2002 “Abiognic formation of alkanes in the Earth’s crust as a minor source for global hydrocarbon reserevoirs.” Nature (letters) Vol 416: 522- 524

Miller, Stanley L.,
1953 “A Production of Amino Acids Under Possible Primitive Earth Conditions” Science vol. 117:528-529

Miller, Stanley, Harold C. Urey
1959 “Organic Compound Synthesis on the Primitive Earth” Science vol 139 Num 3370: 254-251

Miyakawa, Shin, Hiroto Yamanashi, Kensei Kobayashi, H. James Cleaves, Stanley L. Miller
2002 Prebiotic synthesis from CO atmospheres: Implications for the origins of life Proc. Natl. Acad. Sci. USA, Vol. 99, Issue 23, 14628-14631, November 12,

Weber AL.
2002 Prebiotic amino acid thioester synthesis: thiol-dependent amino acid synthesis from formose substrates (formaldehyde and glycolaldehyde) and ammonia. SETI Institute, NASA Ames Research Center, Moffett Field, CA 94035-1000, USA. PMID: 9611766 [PubMed - indexed for MEDLINE]

Abiotic sugars, Abiotic bases

Levy, M and Miller, S.L.,
1998 The stability of the RNA bases: Implications for the origin of life, Proc. Natl. Acad. Sci. USA 95(14):7933–38,

Nelson, K. E., M. Levy, S. L. Miller
2000 “Peptide nucleic acids rather than RNA may have been the first genetic molecule” PNAS-USA v.97, 3868-3871

Nelson K.E., Robertson M.P., Levy M, Miller S.L.
2001 Concentration by evaporation and the prebiotic synthesis of cytosine. Orig Life Evol Biosph Jun;31(3):221-229

Shapiro, Robert
1999 Prebiotic Cytosine Synthesis: A Critical Analysis and Implications for the Origin of Life. Proceedings of the National Academy of Science 96 (8): 4396
*Side reactions make cytosine synthesis unlikely, but see Nelson et al (2001)

V) Polymerization under abiotic conditions
Atmospheric, Cyclic (wet/dry, hot/cold)

Lee DH, Severin K, Yokobayashi Y, and Ghadiri MR,
1997 Emergence of symbiosis in peptide self-replication through a hypercyclic network. Nature, 390: 591-4,

Hydrothermal

Cody, George D., et al
2000 “Primordial Carbonylated Iron-Sulfur Compounds and the Synthesis of Pyruvate” Science v.289 : 1337-1340

Horita, Juske, Michael E. Berndt
1999 Abiogenic Methane Formation and Isotropic Fractionization Under Hydrothermal Conditions. Science 285 (5430): 1055

Huber, Claudia, Gunter Wachtershauser
1997 “Activated Acetic Acid by Carbon Fixation on (Fe,Ni)S Under Primordial Conditions” Science v. 276: 245-247

Huber, Claudia, Gunter Wachtershauser
1998 “Peptides by Activation of Amino Acids with CO on (Ni,Fe)S Surfaces: Implications for the Origin of Life” Science v.281: 670-672

Imai, E., Honda, H., Hatori, K., Brack, A. and Matsuno, K.
1999 “Elongation of oligopeptides in a simulated submarine hydrothermal system“ Science 283(5403):831–833.

Matsuno, Koichiro
2003 Catalytic Capability of Oligopeptides in the Interface Chemistry in Hyrotheremal Environments. MS in the possession of the author.

Schoonen, Martin A. A., Yong Xu
2001 “Nitrogen Reduction Under Hydrothrmal Vent Conditions: Implications for the Prebiotic Synthesis of C-H-O-N Compounds” Astrobiology 1:133-142

Shock, Everett L.
1990 “Geochemical Constraints on the Origin of Organic Compounds in Hydrothernal Systems” Origins of Life and Evolution of the Biosphere v.20: 331-367

Von Damm, K. L.
1995 “Controls on the Chemistry and Temporal Variability of Seafloor Hydrothemal Fluids” in Seafloor Hydrodynamical Systems: Physical, Chemical, Biological, and Geological Interactions Geophysical Monograph 91 The American Geophysical Union

Wachtershauser, Gunter
2000 “Perspective” Science v.289 : 1308

All of these are available (one way or another) on the internet, or at a good library.

Dr.GH

All and all, there are more than enough abiotic sources for amino acids, and the RNA, and DNA bases, and phosphates.

What is lacking is the particular pathway followed here on Earth. It will be easier to observe the origin of life on other planets than it will be to establish its specific origin pathway here on Earth.

Doubting Didymus

How do you mean?

Dr.GH

What is needed to establish the specific chemical pathway to life followed on our planet is a set of chemical, and morphological fossils. It is likely that the origin of life took place in less than 10^7 years and almost as soon as conditions were possible. In short, try to find well preserved rock with minimal metamorphism from between 3.8 and 3.5 billion years ago.

While I think that there are a number of means to extend the time available, there is not much to suggest that 3.8 billion year old rock will provide well preserved fossils.

For example:

Shock, Everett L.
1990 “Geochemical Constraints on the Origin of Organic Compounds in Hydrothernal Systems” Origins of Life and Evolution of the Biosphere v.20: 331-367

and

Fedo, Christopher M. and Martin J. Whitehouse
2002 “Metasomatic Origin of Quartz-Pyroxene Rock, Akilia, Greenland, and Implications for Earth's Earliest Life” Science 296: 1448-1452. (in Reports)

Lazcano, Antonio, Stanley L. Miller
1996 “The Origin and Early Evolution of Life: Prebiotic Chemistry, the Pre-RNA World, and Time” Cell vol 85:793-798

Levy, M and Miller, S.L.,
1998 The stability of the RNA bases: Implications for the origin of life, Proc. Natl. Acad. Sci. USA 95(14):7933–38,

MOJZSIS, STEPHEN J., T. MARK HARRISON, ROBERT T. PIDGEON
2001 ”Oxygen-isotope evidence from ancient zircons for liquid water at the Earth's surface 4,300 Myr ago” Nature 409, 178-181 (11 January )

VAN ZUILENMARK A., AIVO LEPLAND & GUSTAF ARRHENIUS
2002 Reassessing the evidence for the earliest traces of life. Nature Vol 418: 6898, 627-630

Whitehouse, Martin.
2000 “Time Constraints on When Life Began: The oldest Record of Life on Earth?” The Geochemical News #103, April.

Wilde, Simon A., John W. Valley, William H. Peck, Collin M. Graham
2001 “Evidence from detrital zircons for the existance of contenental crust and oceans on Earth 4.4 Gyr ago” Nature (letters) Vol 409:175-181

While there is good data to extend the time available for the origin of life on Earth, it does little to improve the preservation of the meaningful rock. Thus, it will be easier (in some way that avoides the tiny problem of interstellar travel ) to observe the origin of life on some other planet.

Doubting Didymus

You mean, some other planet where the event happened much more recently?

Dr.GH

I mean going to some planet where the event is closer, yes.

Io and some of the other Saturn moons seem candidates. Or there is the notion that Mars got life going and then lost it. The planetary climate changes there may have better preserved geochemical data than the active, life bound Earth.

caravelair

i also need help with the following claim:

and one other thing. he also suggested that since abiogenesis is not falsifiable, an unfalsifiable theistic explanation of the appearance of life is no less scientific. i can't think of a strong argument against this, so hopefully someone here knows a little more philosophy of science than i do.