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Miller-Urey Experiment

The Miller-Urey Experiment was a landmark experiment to investigate the chemical conditions that might have led to the origin of life on Earth. The scientist Stanley Miller, under the supervision of the Nobel laureate scientist Harold Urey conducted it in 1952 at the University of Chicago. They tried to recreate the conditions that could have existed in the first billion years of the Earth’s existence (also known as the Early Earth) to check the said chemical transformations.

Miller-Urey Experiment And The Primordial Soup Theory

The experiment tested the primordial or primeval soup theory developed independently by the Soviet biologist A.I. Oparin and English scientist J.B.S. Haldane in 1924 and 1929 respectively. The theory propounds the idea that the complex chemical components of life on Earth originated from simple molecules occurring naturally in the reducing atmosphere of the Early Earth, sans oxygen. Lightning and rain energized the said atmosphere to create simple organic compounds that formed an organic “soup”. The so-called soup underwent further changes giving rise to more complex organic polymers and finally life.

The Miller-Urey Experiment In Support Of Abiogenesis

From what was explained in the previous paragraph, it can undoubtedly be considered as a classic experiment to demonstrate abiogenesis. For those who are not conversant with the term, abiogenesis is the process responsible for the development of living beings from non-living or abiotic matter. It is thought to have taken place on the Earth about 3.8 to 4 billion years ago.

Miller-Urey Experiment Apparatus and Procedure

The groundbreaking experiment used a sterile glass flask of 5 liters attached with a pair of electrodes, to hold water (H 2 O), methane (CH 4 ), ammonia (NH 3 ) and hydrogen (H 2 ), the major components of primitive Earth. This was connected to another glass flask of 500 ml capacity half filled with water. On heating it, the water vaporized to fill the larger container with water vapor. The electrodes induced continuous electrical sparks in the gas mixture to simulate lightning. When the gas was cooled, the condensed water made its way into a U-shaped trap at the base of the apparatus.

After electrical sparking had continued for a day, the solution in the trap turned pink in color. At the end of a week, the boiling flask was removed, and mercuric chloride added to prevent microbial contamination. After stopping the chemical reaction, the scientist duo examined the cooled water collected to find that 10-15% of the carbon present in the system was in the form of organic compounds. 2% of carbon went into the formation of various amino acids, including 13 of the 22 amino acids essential to make proteins in living cells, glycine being the most abundant.

Though the result was the production of only simple organic molecules and not a complete living biochemical system, still the simple prebiotic experiment could, to a considerable extent, prove the primordial soup hypothesis.

Miller-Urey Experiment Animation

Chemistry of the miller and urey experiment.

The components of the mixture can react among themselves to produce formaldehyde (CH 2 O), hydrogen cyanide (HCN) and other intermediate compounds.

CO 2 → CO + [O] (atomic oxygen)

CH 4 + 2[O] → CH 2 O + H 2 O

CO + NH 3 → HCN + H 2 O

CH 4 + NH 3 → HCN + 3H 2

The ammonia, formaldehyde and HCN so produced react by a process known as Strecker synthesis to form biomolecules including amino acids.

CH 2 O + HCN + NH 3 → NH 2 -CH 2 -CN + H 2 O

NH 2 -CH 2 -CN + 2H 2 O → NH 3 + NH 2 -CH 2 -COOH (glycine)

In addition to the above, formaldehyde and water can react by Butlerov’s reaction to produce a variety of sugars like ribose, etc.

Though later studies have indicated that the reducing atmosphere as replicated by Miller and Urey could not have prevailed on primitive Earth, still, the experiment remains to be a milestone in synthesizing the building blocks of life under abiotic conditions and not from living beings themselves.

https://www.bbc.co.uk/bitesize/guides/z2gjtv4/revision/1

https://www.juliantrubin.com/bigten/miller_urey_experiment.html

Article was last reviewed on Thursday, February 2, 2023

One response to “Miller-Urey Experiment”

This experiment is currently seen as not sufficient to support abiogenesis. See Stephen C. Meyer, James Tour.

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Icon 1 — The Miller-Urey Experiment

The experiment itself

The understanding of the origin of life was largely speculative until the 1920s, when Oparin and Haldane, working independently, proposed a theoretical model for "chemical evolution." The Oparin-Haldane model suggested that under the strongly reducing conditions theorized to have been present in the atmosphere of the early earth (between 4.0 and 3.5 billion years ago), inorganic molecules would spontaneously form organic molecules (simple sugars and amino acids). In 1953, Stanley Miller, along with his graduate advisor Harold Urey, tested this hypothesis by constructing an apparatus that simulated the Oparin-Haldane "early earth." When a gas mixture based on predictions of the early atmosphere was heated and given an electrical charge, organic compounds were formed ( Miller, 1953 ; Miller and Urey, 1959 ). Thus, the Miller-Urey experiment demonstrated how some biological molecules, such as simple amino acids, could have arisen abiotically, that is through non-biological processes, under conditions thought to be similar to those of the early earth. This experiment provided the structure for later research into the origin of life. Despite many revisions and additions, the Oparin-Haldane scenario remains part of the model in use today. The Miller-Urey experiment is simply a part of the experimental program produced by this paradigm.

Wells boils off

Wells says that the Miller-Urey experiment should not be taught because the experiment used an atmospheric composition that is now known to be incorrect. Wells contends that textbooks don't discuss how the early atmosphere was probably different from the atmosphere hypothesized in the original experiment. Wells then claims that the actual atmosphere of the early earth makes the Miller-Urey type of chemical synthesis impossible, and asserts that the experiment does not work when an updated atmosphere is used. Therefore, textbooks should either discuss the experiment as an historically interesting yet flawed exercise or not discuss it at all. Wells concludes by saying that textbooks should replace their discussions of the Miller-Urey experiment with an "extensive discussion" of all the problems facing research into the origin of life.

These allegations might seem serious; however, Wells's knowledge of prebiotic chemistry is seriously flawed. First, Wells's claim that researchers are ignoring the new atmospheric data, and that experiments like the Miller-Urey experiment fail when the atmospheric composition reflects current theories, is simply false. The current literature shows that scientists working on the origin and early evolution of life are well aware of the current theories of the earth's early atmosphere and have found that the revisions have little effect on the results of various experiments in biochemical synthesis. Despite Wells's claims to the contrary, new experiments since the Miller-Urey ones have achieved similar results using various corrected atmospheric compositions ( Figure 1 ; Rode, 1999 ; Hanic et al., 2000 ). Further, although some authors have argued that electrical energy might not have efficiently produced organic molecules in the earth's early atmosphere, other energy sources such as cosmic radiation (e.g., Kobayashi et al., 1998 ), high temperature impact events (e.g., Miyakawa et al., 2000 ), and even the action of waves on a beach ( Commeyras, et al., 2002 ) would have been quite effective.

Even if Wells had been correct about the Miller-Urey experiment, he does not explain that our theories about the origin of organic "building blocks" do not depend on that experiment alone ( Orgel, 1998a ). There are other sources for organic "building blocks," such as meteorites, comets, and hydrothermal vents. All of these alternate sources for organic materials and their synthesis are extensively discussed in the literature about the origin of life, a literature that Wells does not acknowledge. In fact, what is most striking about Wells's extensive reference list is the literature that he has left out. Wells does not mention extraterrestrial sources of organic molecules, which have been widely discussed in the literature since 1961 (see Oró, 1961 ; Whittet, 1997 ; Irvine, 1998 ). Wells apparently missed the vast body of literature on organic compounds in comets (e.g. Oró, 1961 ; Anders, 1989 ; Irvine, 1998 ), carbonaceous meteorites (e.g. Kaplan et al., 1963 ; Hayes, 1967 ; Chang, 1994; Maurette, 1998 ; Cooper et al., 2001 ), and conditions conducive to the formation of organic compounds that exist in interstellar dust clouds ( Whittet, 1997 ).

Wells also fails to cite the scientific literature on other terrestrial conditions under which organic compounds could have formed. These non-atmospheric sources include the synthesis of organic compounds in a reducing ocean (e.g., Chang, 1994 ), at hydrothermal vents (e.g., Andersson, 1999 ; Ogata et al., 2000 ), and in volcanic aquifers ( Washington, 2000 ). A cursory review of the literature finds more than 40 papers on terrestrial prebiotic chemical synthesis published since 1997 in the journal Origins of life and the evolution of the biosphere alone. Contrary to Wells's presentation, there appears to be no shortage of potential sources for organic "building blocks" on the early earth.

Instead of discussing this literature, Wells raises a false "controversy" about the low amount of free oxygen in the early atmosphere. Claiming that this precludes the spontaneous origin of life, he concludes that "[d]ogma had taken the place of empirical science" ( Wells 2000 :18). In truth, nearly all researchers who work on the early atmosphere hold that oxygen was essentially absent during the period in which life originated ( Copley, 2001 ) and therefore oxygen could not have played a role in preventing chemical synthesis. This conclusion is based on many sources of data , not "dogma." Sources of data include fluvial uraninite sand deposits ( Rasmussen and Buick, 1999 ) and banded iron formations ( Nunn, 1998 ; Copley, 2001 ), which could not have been deposited under oxidizing conditions. Wells also neglects the data from paleosols (ancient soils) which, because they form at the atmosphere-ground interface, are an excellent source to determine atmospheric composition ( Holland, 1994 ). Reduced paleosols suggest that oxygen levels were very low before 2.1 billion years ago ( Rye and Holland, 1998 ). There are also data from mantle chemistry that suggest that oxygen was essentially absent from the earliest atmosphere ( Kump et al. 2001 ). Wells misrepresents the debate as over whether oxygen levels were 5/100 of 1%, which Wells calls "low," or 45/100 of 1%, which Wells calls "significant." But the controversy is really over why it took so long for oxygen levels to start to rise. Current data show that oxygen levels did not start to rise significantly until nearly 1.5 billion years after life originated ( Rye and Holland, 1998 ; Copley, 2001 ). Wells strategically fails to clarify what he means by "early" when he discusses the amount of oxygen in the "early" atmosphere. In his discussion he cites research about the chemistry of the atmosphere without distinguishing whether the authors are referring to times before, during, or after the period when life is thought to have originated. Nearly all of the papers he cites deal with oxygen levels after 3.0 billion years ago. They are irrelevant, as chemical data suggest that life arose 3.8 billion years ago ( Chang, 1994 ; Orgel, 1998b ), well before there was enough free oxygen in the earth's atmosphere to prevent Miller-Urey-type chemical synthesis.

Finally, the Miller-Urey experiment tells us nothing about the other stages in the origin of life, including the formation of a simple genetic code (PNA or "peptide"-based codes and RNA-based codes) or the origin of cellular membranes (liposomes), some of which are discussed in all the textbooks that Wells reviewed. The Miller-Urey experiment only showed one possible route by which the basic components necessary for the origin of life could have been created, not how life came to be. Other theories have been proposed to bridge the gap between the organic "building blocks" and life. The "liposome" theory deals with the origin of cellular membranes, the RNA-world hypothesis deals with the origin of a simple genetic code, and the PNA (peptide-based genetics) theory proposes an even simpler potential genetic code ( Rode, 1999 ). Wells doesn't really mention any of this except to suggest that the "RNA world" hypothesis was proposed to "rescue" the Miller-Urey experiment. No one familiar with the field or the evidence could make such a fatuous and inaccurate statement. The Miller-Urey experiment is not relevant to the RNA world, because RNA was constructed from organic "building blocks" irrespective of how those compounds came into existence ( Zubay and Mui, 2001 ). The evolution of RNA is a wholly different chapter in the story of the origin of life, one to which the validity of the Miller-Urey experiment is irrelevant.

What the textbooks say

All of the textbooks reviewed contain a section on the Miller-Urey experiment. This is not surprising given the experiment's historic role in the understanding of the origin of life. The experiment is usually discussed over a couple of paragraphs (see Figure 2 ), a small proportion (roughly 20%) of the total discussion of the origin and early evolution of life. Commonly, the first paragraph discusses the Oparin-Haldane scenario, and then a second outlines the Miller-Urey test of that scenario. All textbooks contain either a drawing or a picture of the experimental apparatus and state that it was used to demonstrate that some complex organic molecules (e.g., simple sugars and amino acids, frequently called "building blocks") could have formed spontaneously in the atmosphere of the early earth. Textbooks vary in their descriptions of the atmospheric composition of the early earth. Five books present the strongly reducing atmosphere of the Miller-Urey experiment, whereas the other five mention that the current geochemical evidence points to a slightly reducing atmosphere. All textbooks state that oxygen was essentially absent during the period in which life arose. Four textbooks mention that the experiment has been repeated successfully under updated conditions. Three textbooks also mention the possibility of organic molecules arriving from space or forming at deep-sea hydrothermal vents ( Figure 2 ). No textbook claims that these experiments conclusively show how life originated; and all textbooks state that the results of these experiments are tentative.

It is true that some textbooks do not mention that our knowledge of the composition of the atmosphere has changed. However, this does not mean that textbooks are "misleading" students, because there is more to the origin of life than just the Miller-Urey experiment. Most textbooks already discuss this fact. The textbooks reviewed treat the origin of life with varying levels of detail and length in "Origin of life" or "History of life" chapters. These chapters are from 6 to 24 pages in length. In this relatively short space, it is hard for a textbook, particularly for an introductory class like high school biology, to address all of the details and intricacies of origin-of-life research that Wells seems to demand. Nearly all texts begin their origin of life sections with a brief description of the origin of the universe and the solar system; a couple of books use a discussion of Pasteur and spontaneous generation instead (and one discusses both). Two textbooks discuss how life might be defined. Nearly all textbooks open their discussion of the origin of life with qualifications about how the study of the origin of life is largely hypothetical and that there is much about it that we do not know.

Wells's evaluation

As we will see in his treatment of the other "icons," Wells's criteria for judging textbooks stack the deck against them, ensuring failure. No textbook receives better than a D for this "icon" in Wells's evaluation, and 6 of the 10 receive an F. This is largely a result of the construction of the grading criteria. Under Wells's criteria (Wells 2000:251-252), any textbook containing a picture of the Miller-Urey apparatus could receive no better than a C, unless the caption of the picture explicitly says that the experiment is irrelevant, in which case the book would receive a B. Therefore, the use of a picture is the major deciding factor on which Wells evaluated the books, for it decides the grade irrespective of the information contained in the text! A grade of D is given even if the text explicitly points out that the experiment used an incorrect atmosphere, as long as it shows a picture. Wells pillories Miller and Levine for exactly that, complaining that they bury the correction in the text. This is absurd: almost all textbooks contain pictures of experimental apparatus for any experiment they discuss. It is the text that is important pedagogically, not the pictures. Wells's criteria would require that even the intelligent design "textbook" Of Pandas and People would receive a C for its treatment of the Miller-Urey experiment.

In order to receive an A, a textbook must first omit the picture of the Miller-Urey apparatus (or state explicitly in the caption that it was a failure), discuss the experiment, but then state that it is irrelevant to the origin of life. This type of textbook would be not only scientifically inaccurate but pedagogically deficient.

Why we should still teach Miller-Urey

The Miller-Urey experiment represents one of the research programs spawned by the Oparin-Haldane hypothesis. Even though details of our model for the origin of life have changed, this has not affected the basic scenario of Oparin-Haldane. The first stage in the origin of life was chemical evolution. This involves the formation of organic compounds from inorganic molecules already present in the atmosphere and in the water of the early earth. This spontaneous organization of chemicals was spawned by some external energy source. Lightning (as Oparin and Haldane thought), proton radiation, ultraviolet radiation, and geothermal or impact-generated heat are all possibilities.

The Miller-Urey experiment represents a major advance in the study of the origin of life. In fact, it marks the beginning of experimental research into the origin of life. Before Miller-Urey, the study of the origin of life was merely theoretical. With the advent of "spark experiments" such as Miller conducted, our understanding of the origin of life gained its first experimental program. Therefore, the Miller-Urey experiment is important from an historical perspective alone. Presenting history is good pedagogy because students understand scientific theories better through narratives. The importance of the experiment is more than just historical, however. The apparatus Miller and Urey designed became the basis for many subsequent "spark experiments" and laid a groundwork that is still in use today. Thus it is also a good teaching example because it shows how experimental science works. It teaches students how scientists use experiments to test ideas about prehistoric, unobserved events such as the origin of life. It is also an interesting experiment that is simple enough for most students to grasp. It tested a hypothesis, was reproduced by other researchers, and provided new information that led to the advancement of scientific understanding of the origin of life. This is the kind of "good science" that we want to teach students.

Finally, the Miller-Urey experiment should still be taught because the basic results are still valid. The experiments show that organic molecules can form under abiotic conditions. Later experiments have used more accurate atmospheric compositions and achieved similar results. Even though origin-of-life research has moved beyond Miller and Urey, their experiments should be taught. We still teach Newton even though we have moved beyond his work in our knowledge of planetary mechanics. Regardless of whether any of our current theories about the origin of life turn out to be completely accurate, we currently have models for the processes and a research program that works at testing the models.

How textbooks could improve their presentations of the origin of life

Textbooks can always improve discussions of their topics with more up-to-date information. Textbooks that have not already done so should explicitly correct the estimate of atmospheric composition, and accompany the Miller-Urey experiment with a clarification of the fact that the corrected atmospheres yield similar results. Further, the wealth of new data on extraterrestrial and hydrothermal sources of biological material should be discussed. Finally, textbooks ideally should expand their discussions of other stages in the origin of life to include PNA and some of the newer research on self-replicating proteins. Wells, however, does not suggest that textbooks should correct the presentation of the origin of life. Rather, he wants textbooks to present this "icon" and then denigrate it, in order to reduce the confidence of students in the possibility that scientific research can ever establish a plausible explanation for the origin of life or anything else for that matter. If Wells's recommendations are followed, students will be taught that because one experiment is not completely accurate (albeit in hindsight), everything else is wrong as well. This is not good science or science teaching.

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Icons of Evolution? Figures
Icons of Evolution? References
"Icons" Critique — pdf versions
Fatally Flawed Iconoclasm
10 Answers to Jonathan Wells's "10 Questions"

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Miller Urey Experiment: Hypothesis, Steps, Conclusions, and Limitations

The Miller Urey Experiment played a crucial role in investigating the origin of life on our planet. This comprehensive guide explores the experiment’s hypothesis, step-by-step process, key findings, and limitations, shedding light on its significance in unraveling the mysteries of life’s beginnings.

Oparin-Haldane Hypothesis

The Oparin-Haldane Hypothesis, proposed by Aleksandr Oparin and J.B.S. Haldane, postulates that life didn’t spontaneously emerge on early Earth due to different environmental conditions. It suggests that life gradually evolved from chemical reactions, starting with the combination of atoms into inorganic molecules and the subsequent formation of simple organic compounds. These compounds then assembled into complex organic structures, ultimately leading to the emergence of the first cell.

Steps of the Miller Urey Experiment

The Miller-Urey experiment, conducted in 1953 by Stanley L. Miller and Harold C. Urey, aimed to simulate early Earth’s conditions and test the Oparin-Haldane Hypothesis. Here are the key steps of the experiment:

Simulating Early Earth’s Atmosphere: The researchers recreated early Earth’s atmosphere in a closed system using a mixture of gases believed to be present during that era. They used a mixture of gases, including methane (CH4), ammonia (NH3), water vapor (H2O), and hydrogen (H2).

Introduction of Energy: Sparks or electric discharges were introduced to simulate the energy sources on early Earth, such as lightning strikes.

Circulation and Condensation: The gas mixture and energy were circulated continuously, mimicking Earth’s water cycle and allowing for the formation of various organic compounds.

Collection and Analysis: Samples were collected from the closed system and analyzed using chromatography and spectrometry to identify and characterize the organic compounds formed during the experiment.

Results and Findings: The experiment produced a variety of organic molecules, including amino acids—the building blocks of proteins —supporting the notion that early Earth’s conditions could have facilitated the synthesis of organic compounds essential for life’s origin.

Conclusions of the Miller Urey Experiment

The Miller-Urey experiment yielded significant conclusions, including:

Organic compounds, including amino acids, can be synthesized from inorganic materials under simulated early Earth conditions.
Basic building blocks of life may have emerged spontaneously from non-living matter.
The experiment demonstrated the potential for diverse organic compound formation, including rare amino acids.
External energy sources played a crucial role in facilitating chemical reactions and organic compound synthesis.
The experiment offered insights into the chemical reactions that might have occurred in early Earth’s atmosphere.
The findings supported the concept of abiogenesis, where life can arise from non-living matter through natural processes.
The Miller-Urey experiment laid the foundation for further research in prebiotic chemistry and the study of life’s origins.

Limitations of the Miller Urey Experiment

It’s important to consider the limitations of the Miller-Urey experiment, which include:

The experiment’s simulation of early Earth’s atmosphere may not perfectly represent the actual conditions.
The specific gases used may not accurately reflect the true composition of early Earth’s atmosphere.
The experiment’s short duration and scale may not fully capture the complexity and length of natural processes involved in life’s origin.
While the experiment produced organic compounds, it didn’t address the assembly of complex biomolecules or replicating systems crucial for life’s origin.

Ongoing Debates and Significance

Critics argue that the experiment oversimplifies the interconnected nature of biochemical systems and may not fully represent the processes behind life’s origin. There is an ongoing debate regarding the specific conditions and pathways leading to life’s emergence, with the Miller-Urey experiment presenting one plausible scenario. While it doesn’t address the origin of genetic information or self-replicating systems, subsequent research has refined and expanded upon its findings, leading to revised interpretations. The Miller-Urey experiment remains a significant milestone in our understanding of prebiotic chemistry and contributes to unraveling the complex puzzle of life’s origin.

In conclusion, the Miller-Urey experiment’s hypothesis, steps, conclusions, and limitations provide valuable insights into the origin of life on Earth. It serves as a foundation for further research, stimulating ongoing debates and refining our understanding of life’s emergence from non-living matter.

Learn more:

Amino Acids: Types, Functions, Sources, and Differences between Essential and Non-Essential Amino Acids

AP®︎/College Biology

Course: ap®︎/college biology > unit 7.

Earth formation
Beginnings of life
Origins of life

Hypotheses about the origins of life

The RNA origin of life
Origins of life on Earth

Key points:

The Earth formed roughly 4.5 ‍ billion years ago, and life probably began between 3.5 ‍ and 3.9 ‍ billion years ago.
The Oparin-Haldane hypothesis suggests that life arose gradually from inorganic molecules, with “building blocks” like amino acids forming first and then combining to make complex polymers.
The Miller-Urey experiment provided the first evidence that organic molecules needed for life could be formed from inorganic components.
Some scientists support the RNA world hypothesis , which suggests that the first life was self-replicating RNA. Others favor the metabolism-first hypothesis , placing metabolic networks before DNA or RNA.
Simple organic compounds might have come to early Earth on meteorites.

Introduction

When did life appear on earth, the earliest fossil evidence of life, how might life have arisen.

Simple inorganic molecules could have reacted (with energy from lightning or the sun) to form building blocks like amino acids and nucleotides, which could have accumulated in the oceans, making a "primordial soup." 3 ‍
The building blocks could have combined in further reactions, forming larger, more complex molecules (polymers) like proteins and nucleic acids, perhaps in pools at the water's edge.
The polymers could have assembled into units or structures that were capable of sustaining and replicating themselves. Oparin thought these might have been “colonies” of proteins clustered together to carry out metabolism, while Haldane suggested that macromolecules became enclosed in membranes to make cell-like structures 4 , 5 ‍ .

From inorganic compounds to building blocks

Were miller and urey's results meaningful, from building blocks to polymers, what was the nature of the earliest life, the "genes-first" hypothesis, the "metabolism-first" hypothesis, what might early cells have looked like, another possibility: organic molecules from outer space.

Miller, Urey, and others showed that simple inorganic molecules could combine to form the organic building blocks required for life as we know it.
Once formed, these building blocks could have come together to form polymers such as proteins or RNA.
Many scientists favor the RNA world hypothesis, in which RNA, not DNA, was the first genetic molecule of life on Earth. Other ideas include the pre-RNA world hypothesis and the metabolism-first hypothesis.
Organic compounds could have been delivered to early Earth by meteorites and other celestial objects.

Works cited:

Harwood, R. (2012). Patterns in palaeontology: The first 3 billion years of evolution. Palaeontology , 2(11), 1-22. Retrieved from http://www.palaeontologyonline.com/articles/2012/patterns-in-palaeontology-the-first-3-billion-years-of-evolution/ .
Wacey, D., Kilburn, M. R., Saunders, M., Cliff, J., and Brasier, M. D. (2011). Microfossils of sulphur-metabolizing cells in 3.4-billion-year-old rocks of Western Australia. Nature Geoscience , 4 , 698-702. http://dx.doi.org/10.1038/ngeo1238 .
Primordial soup. (2016, January 20). Retrieved May 22, 2016 from Wikipedia: https://en.wikipedia.org/wiki/Primordial_soup .
Gordon-Smith, C. (2003). The Oparin-Haldane hypothesis. In Origin of life: Twentieth century landmarks . Retrieved from http://www.simsoup.info/Origin_Landmarks_Oparin_Haldane.html .
The Oparin-Haldane hypothesis. (2015, June 14). In Structural biochemistry . Retrieved May 22, 2016 from Wikibooks: https://en.wikibooks.org/wiki/Structural_Biochemistry/The_Oparin-Haldane_Hypothesis .
Kimball, J. W. (2015, May 17). Miller's experiment. In Kimball's biology pages . Retrieved from http://www.biology-pages.info/A/AbioticSynthesis.html#Miller's_Experiment .
Earth’s early atmosphere. (Dec 2, 2011). In Astrobiology Magazine . Retrieved from http://www.astrobio.net/topic/solar-system/earth/geology/earths-early-atmosphere/ .
McCollom, T. M. (2013). Miller-Urey and beyond: What have learned about prebiotic organic synthesis reactions in the past 60 years? Annual Review of Earth and Planetary Sciences , 41_, 207-229. http://dx.doi.org/10.1146/annurev-earth-040610-133457 .
Powner, M. W., Gerland, B., and Sutherland, J. D. (2009). Synthesis of activated pyrimidine ribonucleotides in prebiotically plausible conditions. Nature , 459 , 239-242. http://dx.doi.org/10.1038/nature08013 .
Lurquin, P. F. (June 5, 2003). Proteins and metabolism first: The iron-sulfur world. In The origins of life and the universe (pp. 110-111). New York, NY: Columbia University Press.
Ferris, J. P. (2006). Montmorillonite-catalysed formation of RNA oligomers: The possible role of catalysis in the origins of life. Philos. Trans. R. Soc. Lond. B. Bio.l Sci ., 361 (1474), 1777–1786. http://dx.doi.org/10.1098/rstb.2006.1903 .
Kimball, J. W. (2015, May 17). Assembling polymers. In Kimball's biology pages . Retrieved from
Montmorillonite. (2016, 28 March). Retrieved May 22, 2016 from Wikipedia: https://en.wikipedia.org/wiki/Montmorillonite .
Wilkin, D. and Akre, B. (2016, March 23). First organic molecules - Advanced. In CK-12 biology advanced concepts . Retrieved from http://www.ck12.org/book/CK-12-Biology-Advanced-Concepts/section/10.8/ .
Hollenstein, M. (2015). DNA catalysis: The chemical repertoire of DNAzymes. Molecules , 20 (11), 20777–20804. http://dx.doi.org/10.3390/molecules201119730 .
Breaker, R. R. and Joyce, G. F. (2014). The expanding view of RNA and DNA function. Chemistry & biology , 21 (9), 1059–1065. http://dx.doi.org/10.1016/j.chembiol.2014.07.008 .
Alberts, B., Johnson, A., Lewis, J., Raff, M., Roberts, K., and Walter, P. (2002). A pre-RNA world probably predates the RNA world. In Molecular biology of the cell (4th ed.). New York, NY: Garland Science. Retrieved from http://www.ncbi.nlm.nih.gov/books/NBK26876/#_A1124_ .
Moran, L. A. (2009, May 15). Metabolism first and the origin of life. In Sandwalk: Strolling with a skeptical biochemist . Retrieved from http://www.simsoup.info/Origin_Landmarks_Oparin_Haldane.html .
Kimball, J. W. (2015, May 17). The first cell? In Kimball's biology pages . Retrieved from http://www.biology-pages.info/A/AbioticSynthesis.html#TheFirstCell?
Kimball, J. W. (2015, May 17). Molecules from outer space? In Kimball's biology pages . Retrieved from http://www.biology-pages.info/A/AbioticSynthesis.html#Molecules_from_outer_space? .
Jeffs, W. (2006, November 30). NASA scientists find primordial organic matter in meteorite. In NASA news . Retrieved from http://www.nasa.gov/centers/johnson/news/releases/2006/J06-103.html .

Additional references:

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Miller-Urey Experiment – Definition & Detailed Explanation – Astrobiology Glossary

Table of Contents

What is the Miller-Urey Experiment?

The Miller-Urey Experiment is a groundbreaking scientific experiment that was conducted in 1953 by chemists Stanley Miller and Harold Urey. The experiment aimed to simulate the conditions of early Earth in order to investigate the origins of life. This experiment is considered one of the most important in the field of astrobiology and has had a significant impact on our understanding of the origins of life on Earth.

How was the Miller-Urey Experiment conducted?

In the Miller-Urey Experiment, Stanley Miller and Harold Urey created a closed system that mimicked the conditions of early Earth’s atmosphere. They used a mixture of gases such as methane, ammonia, hydrogen, and water vapor, which were believed to be present in the atmosphere of early Earth. The gases were circulated through a series of glass tubes and flasks, representing the oceans and atmosphere of the early Earth.

The gases were then subjected to electrical sparks to simulate lightning, which was thought to be a common occurrence in the early Earth’s atmosphere. After running the experiment for a week, Miller and Urey observed that the mixture of gases had produced a variety of organic compounds, including amino acids, which are the building blocks of proteins and essential for life.

What were the key findings of the Miller-Urey Experiment?

The key findings of the Miller-Urey Experiment were groundbreaking in the field of astrobiology. The experiment demonstrated that under the conditions of early Earth, simple organic molecules could spontaneously form from inorganic compounds. This provided evidence that the basic building blocks of life could have originated on Earth through natural processes.

The experiment also showed that the formation of complex organic molecules, such as amino acids, could occur in a relatively short period of time. This suggested that the origins of life may not have required millions of years, but could have happened relatively quickly under the right conditions.

What impact did the Miller-Urey Experiment have on the field of Astrobiology?

The Miller-Urey Experiment had a profound impact on the field of astrobiology. It provided experimental evidence to support the theory that life could have originated on Earth through natural processes. The experiment sparked further research into the origins of life and the conditions that may have existed on early Earth.

The findings of the Miller-Urey Experiment also inspired scientists to explore the possibility of life on other planets. By demonstrating that the basic building blocks of life could form under conditions similar to those found on early Earth, the experiment raised the possibility that life could exist elsewhere in the universe.

How has the Miller-Urey Experiment influenced our understanding of the origins of life on Earth?

The Miller-Urey Experiment has significantly influenced our understanding of the origins of life on Earth. The experiment provided evidence that the basic building blocks of life could have formed through natural processes on early Earth. This has led scientists to consider the possibility that life may be a common occurrence in the universe, given the right conditions.

The findings of the Miller-Urey Experiment have also led to further research into the origins of life and the conditions that may have existed on early Earth. Scientists continue to study the chemical reactions that could have led to the formation of complex organic molecules, with the goal of understanding how life first emerged on our planet.

What are some criticisms of the Miller-Urey Experiment?

While the Miller-Urey Experiment was groundbreaking in its findings, it has also faced criticism from some scientists. One criticism is that the experiment may not accurately reflect the conditions of early Earth’s atmosphere. Some researchers argue that the gases used in the experiment were not representative of the actual composition of the early Earth’s atmosphere.

Another criticism is that the experiment may have produced a higher concentration of organic compounds than would have been present on early Earth. Some scientists believe that the conditions of the experiment were too idealized and may not have accurately reflected the complexity of the early Earth environment.

Despite these criticisms, the Miller-Urey Experiment remains a landmark study in the field of astrobiology. It has paved the way for further research into the origins of life and has inspired scientists to explore the possibility of life beyond Earth. The experiment continues to be studied and referenced in scientific literature, as researchers seek to unravel the mysteries of how life first began on our planet.

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Oparin-Haldane theory

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Oparin-Haldane theory , idea that organic molecules could be formed from abiogenic materials in the presence of an external energy source—e.g., ultraviolet radiation —and that Earth’s primitive atmosphere was reducing (having very low amounts of free oxygen ) and contained ammonia and water vapour, among other gases. The theory emerged in the 1920s, when British scientist J.B.S. Haldane and Russian biochemist Aleksandr Oparin independently set forth similar ideas concerning the conditions required for the origin of life on Earth .

Haldane and Oparin both suspected that the first life-forms appeared in the warm, primitive ocean and were heterotrophic (obtaining preformed nutrients from the compounds in existence on early Earth) rather than autotrophic (generating food and nutrients from sunlight or inorganic materials). Oparin thought that life developed from coacervates, microscopic spontaneously formed spherical aggregates of lipid molecules that are held together by electrostatic forces and that may have been precursors of cells . Oparin’s work with coacervates confirmed that enzymes fundamental for the biochemical reactions of metabolism functioned more efficiently when contained within membrane-bound spheres than when free in aqueous solutions. Haldane, unfamiliar with Oparin’s coacervates, thought that simple organic molecules formed first and in the presence of ultraviolet light became increasingly complex, ultimately forming cells. Haldane and Oparin’s ideas formed the foundation for much of the research on abiogenesis that took place in later decades.

In 1953 American chemists Harold C. Urey and Stanley Miller tested the Oparin-Haldane theory and successfully produced organic molecules from some of the inorganic components thought to have been present on prebiotic Earth. This became known as the Miller-Urey experiment . Modern abiogenesis hypotheses are based largely on the same principles as the Oparin-Haldane theory and the Miller-Urey experiment. Subtle differences exist, however, between the several models that have been set forth, and explanations differ as to whether complex organic molecules first became self-replicating entities lacking metabolic functions or first became metabolizing protocells that then developed the ability to self-replicate.

Chapter 18: Life On Earth

Chapter 1 how science works.

The Scientific Method
Measurements
Units and the Metric System
Measurement Errors
Mass, Length, and Time
Observations and Uncertainty
Precision and Significant Figures
Errors and Statistics
Scientific Notation
Ways of Representing Data
Mathematics
Testing a Hypothesis
Case Study of Life on Mars
Systems of Knowledge
The Culture of Science
Computer Simulations
Modern Scientific Research
The Scope of Astronomy
Astronomy as a Science
A Scale Model of Space
A Scale Model of Time

Chapter 2 Early Astronomy

The Night Sky
Motions in the Sky
Constellations and Seasons
Cause of the Seasons
The Magnitude System
Angular Size and Linear Size
Phases of the Moon
Dividing Time
Solar and Lunar Calendars
History of Astronomy
Ancient Observatories
Counting and Measurement
Greek Astronomy
Aristotle and Geocentric Cosmology
Aristarchus and Heliocentric Cosmology
The Dark Ages
Arab Astronomy
Indian Astronomy
Chinese Astronomy
Mayan Astronomy

Chapter 3 The Copernican Revolution

Ptolemy and the Geocentric Model
The Renaissance
Copernicus and the Heliocentric Model
Tycho Brahe
Johannes Kepler
Elliptical Orbits
Kepler's Laws
Galileo Galilei
The Trial of Galileo
Isaac Newton
Newton's Law of Gravity
The Plurality of Worlds
The Birth of Modern Science
Layout of the Solar System
Scale of the Solar System
The Idea of Space Exploration
History of Space Exploration
Moon Landings
International Space Station
Manned versus Robotic Missions
Commercial Space Flight
Future of Space Exploration
Living in Space
Moon, Mars, and Beyond
Societies in Space

Chapter 4 Matter and Energy in the Universe

Matter and Energy
Rutherford and Atomic Structure
Early Greek Physics
Dalton and Atoms
The Periodic Table
Structure of the Atom
Heat and Temperature
Potential and Kinetic Energy
Conservation of Energy
Velocity of Gas Particles
States of Matter
Thermodynamics
Laws of Thermodynamics
Heat Transfer
Thermal Radiation
Radiation from Planets and Stars
Internal Heat in Planets and Stars
Periodic Processes
Random Processes

Chapter 5 The Earth-Moon System

Earth and Moon
Early Estimates of Earth's Age
How the Earth Cooled
Ages Using Radioactivity
Radioactive Half-Life
Ages of the Earth and Moon
Geological Activity
Internal Structure of the Earth and Moon
Basic Rock Types
Layers of the Earth and Moon
Origin of Water on Earth
The Evolving Earth
Plate Tectonics
Geological Processes
Impact Craters
The Geological Timescale
Mass Extinctions
Evolution and the Cosmic Environment
Earth's Atmosphere and Oceans
Weather Circulation
Environmental Change on Earth
The Earth-Moon System
Geological History of the Moon
Tidal Forces
Effects of Tidal Forces
Historical Studies of the Moon
Lunar Surface
Ice on the Moon
Origin of the Moon
Humans on the Moon

Chapter 6 The Terrestrial Planets

Studying Other Planets
The Planets
The Terrestrial Planets
Mercury's Orbit
Mercury's Surface
Volcanism on Venus
Venus and the Greenhouse Effect
Tectonics on Venus
Exploring Venus
Mars in Myth and Legend
Early Studies of Mars
Mars Close-Up
Modern Views of Mars
Missions to Mars
Geology of Mars
Water on Mars
Polar Caps of Mars
Climate Change on Mars
Terraforming Mars
Life on Mars
The Moons of Mars
Martian Meteorites
Comparative Planetology
Incidence of Craters
Counting Craters
Counting Statistics
Internal Heat and Geological Activity
Magnetic Fields of the Terrestrial Planets
Mountains and Rifts
Radar Studies of Planetary Surfaces
Laser Ranging and Altimetry
Gravity and Atmospheres
Normal Atmospheric Composition
The Significance of Oxygen

Chapter 7 The Giant Planets and Their Moons

The Gas Giant Planets
Atmospheres of the Gas Giant Planets
Clouds and Weather on Gas Giant Planets
Internal Structure of the Gas Giant Planets
Thermal Radiation from Gas Giant Planets
Life on Gas Giant Planets?
Why Giant Planets are Giant
Ring Systems of the Giant Planets
Structure Within Ring Systems
The Origin of Ring Particles
The Roche Limit
Resonance and Harmonics
Tidal Forces in the Solar System
Moons of Gas Giant Planets
Geology of Large Moons
The Voyager Missions
Jupiter's Galilean Moons
Jupiter's Ganymede
Jupiter's Europa
Jupiter's Callisto
Jupiter's Io
Volcanoes on Io
Cassini Mission to Saturn
Saturn's Titan
Saturn's Enceladus
Discovery of Uranus and Neptune
Uranus' Miranda
Neptune's Triton
The Discovery of Pluto
Pluto as a Dwarf Planet
Dwarf Planets

Chapter 8 Interplanetary Bodies

Interplanetary Bodies
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Structure of the Comet Nucleus
Comet Chemistry
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Life Story of Comets
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Gravitational Perturbations
Surveys for Earth Crossing Asteroids
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Composition of Asteroids
Introduction to Meteorites
Origin of Meteorites
Types of Meteorites
The Tunguska Event
The Threat from Space
Probability and Impacts
Impact on Jupiter
Interplanetary Opportunity

Chapter 9 Planet Formation and Exoplanets

Formation of the Solar System
Early History of the Solar System
Conservation of Angular Momentum
Angular Momentum in a Collapsing Cloud
Helmholtz Contraction
Safronov and Planet Formation
Collapse of the Solar Nebula
Why the Solar System Collapsed
From Planetesimals to Planets
Accretion and Solar System Bodies
Differentiation
Planetary Magnetic Fields
The Origin of Satellites
Solar System Debris and Formation
Gradual Evolution and a Few Catastrophies
Chaos and Determinism
Extrasolar Planets
Discoveries of Exoplanets
Doppler Detection of Exoplanets
Transit Detection of Exoplanets
The Kepler Mission
Direct Detection of Exoplanets
Properties of Exoplanets
Implications of Exoplanet Surveys
Future Detection of Exoplanets

Chapter 10 Detecting Radiation from Space

Observing the Universe
Radiation and the Universe
The Nature of Light
The Electromagnetic Spectrum
Properties of Waves
Waves and Particles
How Radiation Travels
Properties of Electromagnetic Radiation
The Doppler Effect
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The Telescope
Optical Telescopes
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Hubble Space Telescope
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Frontier Observatories

Chapter 14 The Milky Way

The Distribution of Stars in Space
Stellar Companions
Binary Star Systems
Binary and Multiple Stars
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Binaries and Stellar Mass
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Gamma Ray Bursts
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The Interstellar Medium
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Groups of Stars
Open Star Clusters
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Layout of the Milky Way
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Mapping the Milky Way

Chapter 15 Galaxies

The Milky Way Galaxy
Mapping the Galaxy Disk
Spiral Structure in Galaxies
Mass of the Milky Way
Dark Matter in the Milky Way
Galaxy Mass
The Galactic Center
Black Hole in the Galactic Center
Stellar Populations
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Edwin Hubble
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Spiral Galaxies
Elliptical Galaxies
Lenticular Galaxies
Dwarf and Irregular Galaxies
Overview of Galaxy Structures
The Local Group
Light Travel Time
Galaxy Size and Luminosity
Mass to Light Ratios
Dark Matter in Galaxies
Gravity of Many Bodies
Galaxy Evolution
Galaxy Interactions
Galaxy Formation

Chapter 16 The Expanding Universe

Galaxy Redshifts
The Expanding Universe
Cosmological Redshifts
The Hubble Relation
Relating Redshift and Distance
Galaxy Distance Indicators
Size and Age of the Universe
The Hubble Constant
Large Scale Structure
Galaxy Clustering
Clusters of Galaxies
Overview of Large Scale Structure
Dark Matter on the Largest Scales
The Most Distant Galaxies
Black Holes in Nearby Galaxies
Active Galaxies
Radio Galaxies
The Discovery of Quasars
Types of Gravitational Lensing
Properties of Quasars
The Quasar Power Source
Quasars as Probes of the Universe
Star Formation History of the Universe
Expansion History of the Universe

Chapter 17 Cosmology

Early Cosmologies
Relativity and Cosmology
The Big Bang Model
The Cosmological Principle
Universal Expansion
Cosmic Nucleosynthesis
Cosmic Microwave Background Radiation
Discovery of the Microwave Background Radiation
Measuring Space Curvature
Cosmic Evolution
Evolution of Structure
Mean Cosmic Density
Critical Density
Dark Matter and Dark Energy
Age of the Universe
Precision Cosmology
The Future of the Contents of the Universe
Fate of the Universe
Alternatives to the Big Bang Model
Particles and Radiation
The Very Early Universe
Mass and Energy in the Early Universe
Matter and Antimatter
The Forces of Nature
Fine-Tuning in Cosmology
The Anthropic Principle in Cosmology
String Theory and Cosmology
The Multiverse
The Limits of Knowledge

Chapter 18 Life On Earth

Nature of Life
Chemistry of Life
Molecules of Life
The Origin of Life on Earth
Origin of Complex Molecules

Miller-Urey Experiment

Pre-RNA World
From Molecules to Cells
Extremophiles
Thermophiles
Psychrophiles
Acidophiles
Alkaliphiles
Radiation Resistant Biology
Importance of Water for Life
Hydrothermal Systems
Silicon Versus Carbon
DNA and Heredity
Life as Digital Information
Synthetic Biology
Life in a Computer
Natural Selection
Tree Of Life
Evolution and Intelligence
Culture and Technology
The Gaia Hypothesis
Life and the Cosmic Environment

Chapter 19 Life in the Universe

Life in the Universe
Astrobiology
Life Beyond Earth
Sites for Life
Complex Molecules in Space
Life in the Solar System
Lowell and Canals on Mars
Implications of Life on Mars
Extreme Environments in the Solar System
Rare Earth Hypothesis
Are We Alone?
Unidentified Flying Objects or UFOs
The Search for Extraterrestrial Intelligence
The Drake Equation
The History of SETI
Recent SETI Projects
Recognizing a Message
The Best Way to Communicate
The Fermi Question
The Anthropic Principle
Where Are They?

Hardly a conversation can be had about the origin of life on Earth without mention of the Miller-Urey experiment. Very little is known about the conditions on Earth during the time that life would have been forming. Harold Urey and his then-graduate student Stanley Miller were amongst the first scientists to postulate about early conditions. They conducted an experiment that has been repeated in its original and altered form for over five decades. Their work has become seminal for those studying the chemistry of the origin of life on Earth.

Although scientists continue to collect new data that sheds light on the subject, there is still quite a bit of debate over the composition of early Earth's atmosphere . What does the atmosphere have to do with the origin of life, you might ask? Well, the chemical composition of the atmosphere strongly influences the types of chemical reactions occurring at the surface of the planet and consequently impacts the conditions under which life would have originated. Based on work published in The Origin of Life by the Russian scientist Alexander Oparin in 1938, Miller suggested that life was forming during a time when Earth's atmosphere consisted of methane, ammonia, water, and hydrogen. This chemical makeup is quite different from our modern atmosphere of nitrogen, oxygen, and other gases. Miller introduced these molecules into a sealed flask, applied an electric discharge, and allowed the system to cycle for a week. What he discovered has impacted origins research for over fifty years.

The original apparatus used by Miller and Urey was quite simple compared to today's standards. It essentially consisted of two glass flasks connected by glass tubing. One flask served as the boiling flask, where gases and other molecules could accumulate in a water phase. The other flask (located above the boiling flask) served as a place where gases could accumulate and mix together. An electrical discharge, meant to simulate lightning to produce free radicals, was provided by using an induction coil.

The experimental procedure was also straightforward. Water was first added to the boiling flask. Then the apparatus was evacuated completely of air. Once the air had been removed, hydrogen gas (H 2 ), methane (CH 4 ), and ammonia (NH 3 ) were pumped into the apparatus. Finally, the water in the flask was boiled and the electrical discharge was started. The entire system was allowed to run continuously for a week.

Like any good scientist, Miller took copious notes of what happened inside the apparatus during the weeklong experiment. After the first day, the water in the flask turned distinctly pink. As the week progressed, the solution inside became redder and redder and also a bit cloudy. Once the experiment was complete, Miller and Urey determined that the cloudiness, or turbidity, of the solution was due to silica from the glass. The reddish color, however, resulted from organic compounds that "stuck" to the silica. Although difficult to see at first, Miller also noted yellow organic molecules.

At the end of the week, Miller collected the contents of the apparatus and tested the contents for amino acids using chromatography. Initial tests confirmed the presence of glycine, alpha-alanine, and beta-alanine and suggested that aspartic acid and alpha-amino-n-butyric acid had also been produced. This list of amino acids falls miles short of the 20 amino acids commonly used by life on Earth. However, Miller and Urey both suspected that other amino acids were also present, but in such small amounts that their detection was difficult to impossible.

The intent of Miller was not to try and produce amino acids. Rather, his intent was to explore the early conditions on Earth and what the naturally occurring results would be. What he discovered was that, although the conditions he proposed are not optimum, organic molecule synthesis could have been a natural consequence in Earth's history. More importantly, Miller and Urey went on to explore amino acid synthesis by developing a more efficient apparatus and altering the initial atmospheric conditions in the simulated environment.

Scientists studying the atmosphere of early Earth now believe that the primary atmospheric constituents were different from those first proposed by Oparin and later tested by Urey. James Kasting at Pennsylvania State University has suggested that the atmosphere on Earth just after the succession of heavy bombardment would have been dominated by carbon dioxide and nitrogen and contained small amounts of carbon monoxide, hydrogen gas, and reduced sulfur gases. Now instead of a simple set of glass flasks connected by tubes and sealed, scientists use complex computer models and mathematical equations to simulate the conditions of early Earth. Unless we develop a time machine, we will never know exactly what the planet was like. But through good observations and critical analysis by all scientists in the field, we will definitely arrive at feasible theories about the beginnings of Earth. The Miller-Urey experiment traveled only the first tentative steps along the road from simple molecules to a cell. But it showed that some of life's core ingredients can form quickly and naturally and that concentrating chemicals and adding energy can lead to a progression from simplicity to complexity.

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Miller-Urey Revisited

Members of NAI ’s Carnegie Institution of Washington, Indiana University, and NASA Goddard Space Flight Center Teams and their colleagues have revisited the Miller-Urey experiments, and found some surprising results.

A classic experiment proving amino acids are created when inorganic molecules are exposed to electricity isn’t the whole story, it turns out. The 1953 Miller-Urey Synthesis had two sibling studies, neither of which was published. Vials containing the products from those experiments were recently recovered and reanalyzed using modern technology. The results are reported in this week’s Science .

One of the unpublished experiments by American chemist Stanley Miller (under his University of Chicago mentor, Nobelist Harold Urey) actually produced a wider variety of organic molecules than the experiment that made Miller famous. The difference between the two experiments is small — the unpublished experiment used a tapering glass “aspirator” that simply increased air flow through a hollow, air-tight glass device. Increased air flow creates a more dynamic reaction vessel, or “vapor-rich volcanic” conditions, according to the present report’s authors.

“The apparatus Stanley Miller paid the least attention to gave the most exciting results,” said Adam Johnson, lead author of the Science report. “We suspect part of the reason for this was that he did not have the analytical tools we have today, so he would have missed a lot.”

Johnson is a doctoral student in IU Bloomington’s Biochemistry Program. His advisor is biogeochemist Lisa Pratt, professor of geological sciences and the director of NASA ’s Indiana-Princeton-Tennessee Astrobiology team.

In his May 15, 1953, article in Science, “A Production of Amino Acids Under Possible Primitive Earth Conditions,” Miller identified just five amino acids: aspartic acid, glycine, alpha-amino-butyric acid, and two versions of alanine. Aspartic acid, glycine and alanine are common constituents of natural proteins. Miller relied on a blotting technique to identify the organic molecules he’d created — primitive laboratory conditions by today’s standards. In a 1955 Journal of the American Chemical Society paper, Miller identified other compounds, such as carboxylic and hydroxy acids. But he would not have been able to identify anything present at very low levels.

Johnson, Scripps Institution of Oceanography marine chemist Jeffrey Bada (the present Science paper’s principal investigator), National Autonomous University of Mexico biologist Antonio Lazcano, Carnegie Institution of Washington chemist James Cleaves, and NASA Goddard Space Flight Center astrobiologists Jason Dworkin and Daniel Glavin examined vials left over from Miller’s experiments of the early 1950s. Vials associated with the original, published experiment contained far more organic molecules than Stanley Miller realized — 14 amino acids and five amines. The 11 vials scientists recovered from the unpublished aspirator experiment, however, produced 22 amino acids and the same five amines at yields comparable to the original experiment.

“We believed there was more to be learned from Miller’s original experiment,” Bada said. “We found that in comparison to his design everyone is familiar with from textbooks, the volcanic apparatus produces a wider variety of compounds.”

Johnson added, “Many of these other amino acids have hydroxyl groups attached to them, meaning they’d be more reactive and more likely to create totally new molecules, given enough time.”

The results of the revisited experiment delight but also perplex.

What is driving the second experiment’s molecular diversity? And why didn’t Miller publish the results of the second experiment?

A possible answer to the first question may be the increased flow rate itself, Johnson explained. “Removing newly formed molecules from the spark by increasing flow rate seems crucial,” he said. “It’s possible the jet of steam pushes newly synthesized molecules out of the spark discharge before additional reactions turn them into something less interesting. Another thought is that simply having more water present in the reaction allows a wider variety of reactions to occur.”

An answer to the second question is relegated to speculation — Miller, still a hero to many scientists, succumbed to a weak heart in 2007. Johnson says he and Bada suspect Miller wasn’t impressed with the experiment two’s results, instead opting to report the results of a simpler experiment to the editors at Science.

Miller’s third, also unpublished, experiment used an apparatus that had an aspirator but used a “silent” discharge. This third device appears to have produced a lower diversity of organic molecules.

Research on early planetary geochemistry and the origins of life isn’t limited to Earth studies. As humans explore the Solar System, investigations of past or present extra-terrestrial life are inevitable. Recent speculations have centered on Mars, whose polar areas are now known to possess water ice, but other candidates include Jupiter’s moon Europa and Saturn’s moon Enceladus, both of which are covered in water ice. The NASA Astrobiology Institute, which supports these investigations, has taken a keen interest in the revisiting of the Miller-Urey Synthesis.

“This research is both a link to the experimental foundations of astrobiology as well as an exciting result leading toward greater understanding of how life might have arisen on Earth,” said Carl Pilcher, director of the NASA Astrobiology Institute, headquartered at NASA Ames Research Center in Mountain View, Calif.

Henderson Cleaves (Carnegie Institution for Science) also contributed to the report. It was funded with grants from the NASA Astrobiology Institute, the Marine Biological Laboratory in Woods Hole, Mass., and Mexico’s El Consejo Nacional de Ciencia y Tecnologia.

Scripps Institution of Oceanography is a research center of the University of California at San Diego.

The NASA Astrobiology Institute ( NAI ), founded in 1998, is a partnership among NASA , 16 U.S. teams and five international consortia. NAI ’s goal is to promote, conduct and lead interdisciplinary astrobiology research and to train a new generation of astrobiology researchers. For more information, see http://astrobiology.nasa.gov/nai.

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Miller-Urey Experiment

A classic experiment in molecular biology and genetics , the Miller-Urey experiment, established that the conditions that existed in Earth's primitive atmosphere were sufficient to produce amino acids, the subunits of proteins comprising and required by living organisms. In essence, the Miller-Urey experiment fundamentally established that Earth's primitive atmosphere was capable of producing the building blocks of life from inorganic materials.

In 1953, University of Chicago researchers Stanley L. Miller and Harold C. Urey set up an experimental investigation into the molecular origins of life. Their innovative experimental design consisted of the introduction of the molecules thought to exist in early Earth's primitive atmosphere into a closed chamber. Methane (CH 4 ), hydrogen (H 2 ), and ammonia (NH 3 ) gases were introduced into a moist environment above a water-containing flask. To simulate primitive lightning discharges, Miller supplied the system with electrical current.

After a few days, Miller observed that the flask contained organic compounds and that some of these compounds were the amino acids that serve as the essential building blocks of protein. Using chromatological analysis, Miller continued his experimental observations and confirmed the ready formation of amino acids, hydroxy acids, and other organic compounds.

Although the discovery of amino acid formation was of tremendous significance in establishing that the raw materials of proteins were easy to obtain in a primitive Earth environment, there remained a larger question as to the nature of the origin of genetic materials—in particular the origin of DNA and RNA molecules.

Illustration showing apparatus used in the Miller-Urey experiment to duplicate conditions on primordial Earth. Photograph by Francis Leroy, Biocosmos/Science Photo Library. Photo Researchers, Inc. Reproduced by permission.

Continuing on the seminal work of Miller and Urey, in the early 1960s Juan Oro discovered that the nucleotide base adenine could also be synthesized under primitive Earth conditions. Oro used a mixture of ammonia and hydrogen cyanide (HCN) in a closed aqueous enviroment.

Oro's findings of adenine, one of the four nitrogenous bases that combine with a phosphate and a sugar (deoxyribose for DNA and ribose for RNA) to form the nucleotides represented by the genetic code: (adenine (A), thymine (T), guanine (G), and cytosine (C). In RNA molecules, the nitrogenous base uracil (U) substitutes for thymine. Adenine is also a fundamental component of adenosine triphosphate (ATP), a molecule important in many genetic and cellular functions.

Subsequent research provided evidence of the formation of the other essential nitrogenous bases needed to construct DNA and RNA.

The Miller-Urey experiment remains the subject of scientific debate. Scientists continue to explore the nature and composition of Earth's primitive atmosphere and thus, continue to debate the relative closeness of the conditions of the Miller-Urey experiment (e.g., whether or not Miller's application of electrical current supplied relatively more electrical energy than did lightning in the primitive atmosphere). Subsequent experiments using alternative stimuli (e.g., ultraviolet light ) also confirm the formation of amino acids from the gases present in the Miller-Urey experiment. During the 1970s and 1980s, astrobiologists and astrophyicists, including American physicist Carl Sagan, asserted that ultraviolet light bombarding the primitive atmosphere was far more energetic that even continual lightning discharges. Amino acid formation is greatly enhanced by the presence of an absorber of ultraviolet radiation such as the hydrogen sulfide molecules (H 2 S) also thought to exist in the early Earth atmosphere.

Although the establishment of the availability of the fundamental units of DNA, RNA and proteins was a critical component to the investigation of the origin of biological molecules and life on Earth, the simple presence of these molecules is a long step from functioning cells. Scientists and evolutionary biologists propose a number of methods by which these molecules could concentrate into a crude cell surrounded by a primitive membrane .

See also Astrobiology ; Evolution, convergent ; Evolution, divergent ; Evolution, evidence of ; Evolution, parallel ; Evolutionary change, rate of .

Bonner, J. T. First Signals: The Evolution of Multicellular Development. Princeton, NJ: Princeton University Press, 2000.

Lodish, H., et. al. Molecular Cell Biology. 4th ed. New York: W. H. Freeman & Co., 2000.

Periodicals

Kerridge J.F. "Formation and Processing of Organics in the Early Solar System." Space Sci Rev. 90(1999):275-88.

Miller SL, Urey HC, Oro J. "Origin of Organic Compounds on the Primitive Earth and in Meteorites." J Mol Evol. 9 (1976):59-72.

K. Lee Lerner

Additional topics

Millenarianism - Latin America and Native North America - Old World Origins, Importance In Latin America And Native North America, Bibliography
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Miller Urey Experiment

Miller and urey experiment.

Stanley L. Muller and Harold C. Urey performed an experiment to describe the origin of life on earth. They were of the idea that the early earth’s atmosphere was able to produce amino acids from inorganic matter. The two biologists made use of methane, water, hydrogen, and ammonia which they considered were found in the early earth’s atmosphere. The chemicals were sealed inside sterile glass tubes and flasks connected together in a loop and circulated inside the apparatus.

One flask is half-filled with water and the other flask contains a pair of electrodes. The water vapour was heated and the vapour released was added to the chemical mixture. The released gases circulated around the apparatus imitating the earth’s atmosphere. The water in the flask represents the water on the earth’s surface and the water vapour is just like the water evaporating from lakes, and seas. The electrodes were used to spark the fire to imitate lightning and storm through water vapour.

The vapours were cooled and the water condensed. This condensed water trickles back into the first water flask in a continuous cycle. Miller and Urey examined the cooled water after a week and observed that 10-15% of the carbon was in the form of organic compounds. 2% of carbon had formed 13 amino acids . Yet, the Miller and Urey experiments were condemned by their fellow scientists.

Criticism of the Miller Urey Experiment

The experiment failed to explain how proteins were responsible for the formation of amino acids. A few scientists have contradicted that the gases used by Miller and Urey are not as abundant as shown in the experiment. They were of the notion that the gases released by the volcanic eruptions such as oxygen, nitrogen, and carbon dioxide make up the atmosphere. Therefore, the results are not reliable.

Oparin and Haldane

In the early 20th century, Oparin and Haldane suggested that if the atmosphere of the primitive earth was reducing and if it had sufficient supply of energy such as ultraviolet radiations and lightning, organic compounds would be synthesized at a wide range.

Oparin believed that the organic compounds would have undergone a series of reactions to form complex molecules. He suggested that the molecules formed coacervates in the aqueous environment.

Haldane proposed that the atmosphere of the primordial sea was devoid of oxygen, and was a composed of ammonia, carbon dioxide, and ultraviolet light. This gave rise to a host of organic compounds. The sea contained large amounts of organic monomers and polymers, and the sea was called a ‘hot dilute soup’. He conceived that the polymers and monomers acquired lipid membranes. The molecules further developed and gave rise to the first living organism. ‘Prebiotic soup’ was the term coined by Haldane.

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Miller Urey Experiment

Many consider discussions on how life originated on earth to be purely hypothetical, but in 1952 two American chemists--Harold C. Urey and Stanley Miller--set out to test the time's most prominent ' origin of life on earth ' theory. Here, we will learn about the Miller-Urey experiment !

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First, we will look at the definition of the Miller-Urey experiment.
Then, we will talk about the results of the Miller-Urey experiment.
After, we will explore the significance of the Miller-Urey experiment.

The Definition of the Miller-Urey Experiment

Let's start by looking at the definition of the Miller-Urey experiment.

The Miller-Urey Experiment is a key test tube earth experiment which kick-started evidence-based research into the origin of life on earth .

The Miller-Urey experiment was an experiment that tested the Oparin-Haldane Hypothesis which was, at the time, a highly regarded theory for the evolution of life on earth through chemical evolution.

What was the Oparin-Haldane Hypothesis?

The Oparin-Haldane Hypothesis suggested life emerged from a series of step by step reactions between inorganic matter driven by a large energy input. These reactions initially produced the 'building blocks' of life (e.g., amino acids and nucleotides ), then more and more complex molecules until primitive life forms arose.

Miller and Urey set out to demonstrate that organic molecules could be produced from the simple inorganic molecules present in the primordial soup as the Oparin-Haldane Hypothesis proposed.

Miller-Urey Experiment Figure 1: Urey | Vaia

We now refer to their experiments as the Miller-Urey Experiment and credit the scientists with uncovering the first significant evidence for the origin of life through chemical evolution.

The Oparin-Haldane Hypothesis--note that this point is important--described life emerging in the oceans and under methane-rich reducing atmospheric conditions . So, these were the conditions that Miller and Urey attempted to mimic.

Reducing atmosphere: An oxygen-deprived atmosphere where oxidation can't occur, or occurs at very low levels.

Oxidizing atmosphere: An oxygen-rich atmosphere where molecules in the form of released gases and surface material are oxidized to a higher state.

Miller and Urey attempted to recreate the reducing primordial atmospheric conditions laid out by Oparin and Haldane (Figure 2) by combining four gases in an enclosed environment:

Water vapor

Molecular hydrogen

The pair of scientists then stimulated their faux atmosphere with electrical pules to simulate energy provided by lightning, UV rays or hydrothermal vents and left the experiment running to see if the building blocks for life would form.

Miller-Urey Experiment Results

After running for a week, the liquid simulating the ocean inside their apparatus turned a brownish-black color.

Miller and Urey's analysis of the solution showed complex stepwise chemical reactions had occurred forming simple organic molecules , including amino acids - proving organic molecules could form under the conditions laid out in the Oparin-Haldane hypothesis.

Before these findings, scientists had thought the building blocks of life like amino acids could only be produced by life, inside an organism.

With this, the Miller-Urey Experiment produced the first evidence that organic molecules could be spontaneously produced from only inorganic molecules, suggesting Oparin's primordial soup could have existed at some point in Earth's ancient history.

The Miller-Urey experiment did not, however, fully back up the Oparin-Haldane hypothesis as it only tested the initial stages of chemical evolution , and didn't dive deeper into the role of coacervates and membrane formation .

Miller-Urey Experiment Debunked

The Miller-Urey experiment was modelled on, and recreated conditions laid out under the Oparin-Haldane Hypothesis. Primarily recreating the reducing atmospheric conditions the previous pair stipulated was crucial for the formation of early life.

Though recent geochemical analysis of the earth's primordial atmosphere paints a different picture...

Scientists now think the earth's primordial atmosphere was composed mainly of carbon dioxide and nitrogen: an atmospheric makeup very different from the heavy ammonia and methane atmosphere that Miller and Urey recreated.

These two gases that were featured in their initial experiment are now thought to have been found in a very low concentration if they were present at all!

The Miller-Urey Experiment Undergoes Further Testing

In 1983, Miller attempted to recreate his experiment using the updated mixture of gases - but failed to produce much more than a few amino acids.

More recently American chemists have again repeated the famous Miller-Urey Experiment using the more accurate gaseous mixtures.

Whilst their experiments returned similarly poor amino acid turn out, they noticed nitrates forming in the product. These nitrates were able to break down amino acids as quickly as they formed, yet in the conditions of primordial earth iron and carbonate minerals would have reacted with these nitrates before they had the chance to do so.

Adding these crucial chemicals to the mix produces a solution that, whilst not as complex as the initial findings of the Miller-Urey Experiment, is abundant in amino acids.

These findings have renewed hope that continued experiments will further pin down likely hypotheses, scenarios, and conditions for the origin of life on earth.

Debunking the Miller-Urey Experiment: Chemicals from Space

Whilst the Miller-Urey Experiment proved organic matter can be produced from inorganic matter alone, some scientists are not convinced this is strong enough evidence for the origin of life through chemical evolution alone. The Miller-Urey Experiment failed to produce all the building blocks needed for life - some complex nucleotides have yet to be produced even in subsequent experiments.

The competition's answer to how these more complex building blocks came about is: matter from space. Many scientists believe these complex nucleotides could have been brought to earth through meteorite collisions, and from there evolved into the life that occupies our planet today. However, it is important to note this is just one of the many origin of life theories .

Miller-Urey Experiment Conclusion

The Miller-Urey Experiment was a test tube earth experiment, recreating the reducing primordial atmospheric conditions thought to have been present during the origin of life on earth.

The Miller Urey experiment set out to provide evidence for the Oparin-Haldane hypothesis and has provided evidence for the occurrence of the first simple steps of chemical evolution. Giving validity to Darwin's puddle and Oparin's primordial soup theories.

Perhaps more importantly, however, is the field of pre-biotic chemical experiments which followed. Thanks to Miller and Urey we now know more than previously thought possible about potential ways life could have originated.

The significance of the Miller-Urey Experiment

Before Miller and Urey performed their famous experiments, ideas such as Darwin's puddle of chemistry and life and Oparin's primordial soup were nothing more than speculation.

Miller and Urey devised a way to put some ideas about the origin of life to the test. Their experiment has also prompted a wide variety of research and similar experiments showing similar chemical evolution under a wide range of conditions and subject to different energy sources.

The main component of all living organisms is organic compounds. Organic compounds are complex molecules with carbon at the center. Prior to the findings of the Miller-Urey Experiment it was thought these complex biotic chemicals could only be produced by life forms.

The Miller-Urey Experiment, however, was a pivotal moment in the history of research into the origin of life on earth - as Miller and Urey provided the first evidence that organic molecules could come from inorganic molecules. With their experiments, a whole new field of chemistry, known as pre-biotic chemistry was born.

More recent investigations into the apparatus used by Miller and Urey have added further validity to their experiment. In the 1950s when their famous experiment was carried out glass beakers were the gold standard. But glass is made of silicates, and this could have leeched into the experiment affecting the results.

Scientists have since recreated the Miller-Urey experiment in glass beakers and Teflon alternatives. Teflon is not chemically reactive, unlike glass. These experiments showed more complex molecules forming with the use of glass beakers. At first glance, this would appear to cast further doubt on the applicability of the Miller-Urey experiment. However, the silicates contained in glass are very similar to the silicates present in the earth's rock. These scientists, therefore, suggest that primordial rock acted as a catalyst for the origin of life through chemical evolution. 3

Miller Urey Experiment - Key takeaways

The Miller-Urey Experiment was a revolutionary experiment which birthed the field of pre-biotic chemistry.
Miller and Urey provided the first evidence that organic molecules could come from inorganic molecules.
This evidence of simple chemical evolution transformed ideas from the likes of Darwin and Oparin from speculation to respectable scientific hypotheses.
Whilst the reducing atmosphere mimicked by the Miller-Urey is no longer thought to be reflective of primordial earth, their experiments paved the way for further experimentation with different conditions and energy inputs.
Kara Rogers, Abiogenesis, Encyclopedia Britannica, 2022.
Tony Hyman et al, In Retrospect: The Origin of Life, Nature, 2021.
Jason Arunn Murugesu, Glass flask catalysed famous Miller-Urey origin-of-life experiment, New Scientist, 2021.
Douglas Fox, Primordial Soup's On: Scientists Repeat Evolution's Most Famous Experiment, Scientific American, 2007.
Figure 1: Urey (https://www.flickr.com/photos/departmentofenergy/11086395496/) by U.S. Department of Energy (https://www.flickr.com/photos/departmentofenergy/). Public domain.

Flashcards in Miller Urey Experiment 15

What did the Miller-Urey experiment provide evidence for?

The Miller-Urey Experiment provided the first evidence that organic molecules could come from inorganic molecules which is important in research on the origin of life on Earth.

Prior to the findings of the Miller-Urey Experiment it was thought that ____ could only be produced by life forms.

organic compounds

In 1953 American chemists Harold C. Urey and Stanley Miller set out to test the Oparin-Haldane Hypothesis. What did the Oparin-Haldane Hypothesis say about the evolution of life on earth?

The Oparin-Haldane Hypothesis suggested life emerged from a series of step by step reactions between inorganic matter driven by a large energy input. These reactions initially produced the 'building blocks' of life (e.g., amino acids and nucleotides), then more and more complex molecules until primitive life forms arose.

___ is defined as a n oxygen-deprived atmosphere where oxidation can't occur, or occurs at very low levels.

reducing atmosphere

___ is defined as a n oxygen-rich atmosphere where molecules in the form of released gases and surface material are oxidized to a higher state.

oxidizing atmosphere

How did Miller and Urey recreate the reducing primordial atmospheric conditions laid out by Oparin and Haldene?

Miller and Urey attempted to recreate the reducing primordial atmospheric conditions laid out by Oparin and Haldane by combining water vapor, methane, ammonia, and molecular hydrogen in an enclosed environment.

Then, they stimulated their faux atmosphere with electrical pules to simulate energy provided by lightning, UV rays or hydrothermal vents and left the experiment running to see if the building blocks for life would form.

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Frequently Asked Questions about Miller Urey Experiment

What was the purpose of Miller and Urey's experiment?

Miller and Urey’s experiments set out to test whether life could have emerged from the chemical evolution of simple molecules in the primordial soup, as laid out by the Oparin-Haldane Hypothesis.

What did the Miller Urey experiment demonstrate?

The Miller Urey experiment was the first to demonstrate how organic molecules could have formed under the reducing primordial atmospheric conditions laid out in the Oparin-Haldane hypothesis.

What was the Miller Urey experiment?

The Miller Urey experiment was a test tube earth experiment, recreating the reducing primordial atmospheric conditions thought to have been present during the origin of life on earth. The Miller Urey experiment set out to provide evidence for the Oparin-Haldane hypothesis.

What is the significance of the Miller Urey experiment?

The Miller Urey experiment is significant because it provided the first evidence that organic molecules could be spontaneously produced from only inorganic molecules. Whist the conditions recreated in this experiment are no longer likely to be accurate, the Miller-Urey paved the way for future origin of life on earth experiments.

How does the Miller Urey experiment work?

The Miller Urey experiment consisted of an enclosed environment containg heater water and various other compounds thought to have been present in the primordial soup according to the Oparin-Haldane hypothesis. Electrical currents were applied to the experiment and after a week simple organic molecules were found in the enclosed space.

Test your knowledge with multiple choice flashcards

___ is defined as an oxygen-deprived atmosphere where oxidation can't occur, or occurs at very low levels.

___ is defined as an oxygen-rich atmosphere where molecules in the form of released gases and surface material are oxidized to a higher state.

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Primordial soup was edible: abiotically produced Miller-Urey mixture supports bacterial growth

1 Division of Physiological Chemistry I, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Scheelesväg 2, SE-17 177 Stockholm, Sweden

Daniel Backman

Albert t. lebedev.

2 Department of Organic Chemistry, Moscow State M. V. Lomonosov University, 119991, Moscow, Russia

Viatcheslav B. Artaev

3 LECO Corporation, 3000 Lakeview Avenue, St Joseph, MI, USA

Liying Jiang

4 Department of Environmental Science and Analytical Chemistry, University of Stockholm, Stockholm, Sweden

Leopold L. Ilag

Roman a. zubarev, associated data.

Sixty years after the seminal Miller-Urey experiment that abiotically produced a mixture of racemized amino acids, we provide a definite proof that this primordial soup, when properly cooked, was edible for primitive organisms. Direct admixture of even small amounts of Miller-Urey mixture strongly inhibits E. coli bacteria growth due to the toxicity of abundant components, such as cyanides. However, these toxic compounds are both volatile and extremely reactive, while bacteria are highly capable of adaptation. Consequently, after bacterial adaptation to a mixture of the two most abundant abiotic amino acids, glycine and racemized alanine, dried and reconstituted MU soup was found to support bacterial growth and even accelerate it compared to a simple mixture of the two amino acids. Therefore, primordial Miller-Urey soup was perfectly suitable as a growth media for early life forms.

Abiogenesis theory pioneered by Alexandr Oparin (1894–1980) postulates that under proper conditions life can arise spontaneously from non-living molecules. Oparin’s book, The Origin of Life , was first published in 1924 and quickly became a worldwide bestseller 1 . Oparin speculated that life has emerged through random processes in ‘a biochemical soup’ that once existed in the oceans. According to that theory, spontaneous origination of life requires the presence of the correct mix of chemicals and free energy. The organic molecules necessary for life have been created in the atmosphere of early Earth by such forces as lightning, electric discharges from the sun wind, ultraviolet light and meteorites. These molecules rained from atmosphere into the primitive oceans, where the free energy necessary for life self-organization was supplied by deep-sea hydrothermal vents, hot springs, volcanoes, and earthquakes. Over the decades after Oparin’s book was published, Haldane 2 , Bernal 3 , Calvin 4 and Urey 5 tried to produce evidence supporting this scenario. The critical breakthrough came in 1953 from the experiment performed by Stanley Miller (1930–2007), a graduate student of Harold Urey (1893–1981). Following the instruction of Urey who believed at a time that the early atmosphere was reducing and contained large amounts of methane 6 , Miller introduced water as well as a mixture of hydrogen, methane and ammonia gases in a closed apparatus, and then subjected this mixture to a high-voltage (60 kV) electric discharge for a week, while the water was simultaneously heated. The products accumulated in a water trap below a water-cooled condenser 7 . Since 1953, this experiment has been repeated hundreds of times in dozens of labs. There now are even video instructions available how to construct and run the apparatus 8 .

The experiment usually progresses as follows. Within a day or two of sparking and heating, a pink stain is formed on the sides of the discharge flask, and the water in the trap acquires yellowish color. After several days, the stain turns dark red, and then turbid, while the trap water changes color from yellow to dark brown. At the end, the primary substances in the gaseous phase become carbon monoxide CO and nitrogen N 2 . The dominant material in the water trap is a complex mixture of organic molecules, including aldehydes and cyanides, as well as ‘tar’, mostly insoluble in water 9 . The simplest biologically useful amino acids are also present — mostly glycine and alanine, that together compose 1–3% of the solid residue, as well as smaller amounts of other biological amino acids 10 . Both L- and D- chiral forms of amino acids are produced in roughly equal amounts (racemic mixture), even though a recent report suggests that biologically relevant L-forms may be somewhat more abundant 11 .

Miller-Urey experiment marked the beginning of a new scientific field - prebiotic chemistry 12 ; it is now the most commonly cited evidence for abiogenesis in science textbooks 13 . Yet sixty years after this seminal experiment, the debate is still ongoing whether it represents a definite argument for spontaneous life emergence, or even whether the brown soup produced in this experiment can support life 14 . It has been argued that, besides highly toxic for some organisms gaseous CO, as well as aldehydes and cyanides in solution, the Miller-Urey mixture (MU mixture) contains D-amino acids that, according to some research 15 , 16 , can also be toxic to biological organisms 14 .

Some of the above argumentation can be easily refuted. For instance, for methanogenic archaea, carbon monoxide is a nutrient. Furthermore, Kun and Somerville have obtained in 1971 a strain of Escherichia coli that could metabolize several D-amino acids, including D-alanine and D-glutamic acid 17 . But in general, there has been a surprising lack of experimental proof that the MU mixture produced from simple gases can indeed support life of primitive organisms. Here we attempted to fill this gap.

Miller-Urey experiment

Methane (CH 4 ), hydrogen (H 2 ), and ammonia (NH 3 ) gases were purchased from Strandmøllen (Sweden). Glycerol stock of E. coli BL21 strain adapted for M9 minimal media was obtained as described in literature 18 . Chemicals used to prepare Control media, including DL-Alanine, Glycine, disodium hydrogen phosphate (Na 2 HPO 4 .2H 2 O), monopotassium phosphate (KH 2 PO 4 ), sodium chloride (NaCl), magnesium sulfate (MgSO 4 ), calcium chloride (CaCl 2 ), and ammonium chloride (NH 4 Cl), were obtained from Sigma-Aldrich (Schnelldorf, Germany). Pure water was prepared with a Milli-Q device from Millipore (Billerica, MA, USA). Vacuum filtration system with a 0.2 μm polyethersulfone (PES) membrane for bacteria media sterilization was purchased from VWR (Stockholm, Sweden). 10 kDa Amicon filters (0.5 mL) and 0.2 μm syringe filters were purchased from Millipore. Petri dishes (90 × 15 mm), inoculating loops and corning sterile culture tubes (16 × 125 mm) were purchased from Sigma-Aldrich. Sterile plastic conical tubes (50 mL and 15 mL) for sample preparation were purchased from Sarstedt (Nümbrecht, Germany). The BioScreen C automatic fermentor was obtained from Oy Growth Curves AB Ltd (Helsinki, Finland).

The Miller-Urey apparatus ( Fig. S1 ) was assembled according to literature 19 . After evacuating the whole apparatus by the pump, all the outlets were closed and held sealed for 2 h to ensure absence of leakage. Then about 250 mL of distilled water was added into the boiling flask, and boiling was started to remove all gasses dissolved in water. After that, the system was cooled down and re-evacuated to remove the released gases. Then, hydrogen was added to 169 mbar pressure after evacuating the hydrogen gas line. Then the manifold and hydrogen line were re-evacuated. Similarly, methane was loaded to 508 mbar, and finally ammonia was loaded to 846 mbar. After the gas loading, the heater was turned on to make continuous and gentle boiling. After the pressure became stable, sparking was started with a minimum voltage to maintain the spark continuously. Samples of MU mixtures were taken from the U-shape of the apparatus every one or two days of abiotic synthesis and stored in a freezer for further use.

GC/MS analysis

MU sample was split into two equal portions. The “accelerated water sample preparation - AWASP” method 20 was used for extraction: 1 mL of dichloromethane was added to the first portion of the sample, followed by addition of ~0.5 g of sodium sulfate to bind water. The sample was vigorously shaken. The transparent dichloromethane phase was transferred to another vial (Sample 1a). The same procedure was repeated with the second half of the sample, while acetonitrile was used instead of dichloromethane as an organic solvent (Sample 2a).

For derivatization, 25 μL of MSTFA was added to Sample 1a and the vial was heated to 40 °C for 25 min. In Sample 1b, the solvent was completely removed in a SpeedVac, then 25 μL of MSTFA was added and the temperature of the reaction mixture was increased to 80 °C for 15 min. Sample 1b was then transferred to a GC vial with a 250 μL insert. All samples were subjected to identical GC/MS analysis. Chromatographic separation of the molecules was performed using an Rxi-5SilMS column 30 m × 0.25 mm (id) × 0.25 mm (df) (Restek Corporation, Bellefonte, PA) with a helium flow of 1 mL/min. All injection volumes were 2 μL, split 10:1. The septum purge flow was 3 mL/min. The temperature of the injector, transfer line and ion source was 250 °C. A 3 min solvent delay was imposed for all runs. Prior to all experiments, the source and instrument ion optics were tuned using FC-43. The oven program was as follows: 3 min isothermal at 30 °C, then 10 °C/min to 180 °C and then 12 min isothermal before cooling. High-resolution accurate-mass GC-MS data were obtained using a Pegasus GC-HRT time-of-flight mass spectrometer (LECO Corporation, St Joseph, MI, USA) coupled to an Agilent 7890 A Gas Chromatograph (Agilent, Palo Alto, CA, USA). The system was controlled by the ChromaTOF-HRT software version 1.90.33 (LECO Corporation), which was also used for data collection and data processing. The data were collected using 10 full (26–510 m/z range) spectra per second in high resolution mode (25,000 at FWHM). Mass spectra were searched using NIST14 mass spectral library containing 276,248 electron ionization mass spectra of 242,466 compounds. In all cases, the identified compounds represented the best hit; the accepted threshold score (Match factor) was 750. The molecular mass tolerance was ±5 ppm. Since the molecular masses of all identified compounds were below 200 Da, such mass accuracy provided unique elemental composition. Furthermore, matched experimental mass spectra were manually inspected for the presence of significant fragment ions.

LC/MS amino acid analysis

Amino acid standards ( puriss p. a .) were purchased from commercial suppliers. Solvent acetonitrile (HPLC grade) was obtained from Sigma-Aldrich and water was purified by in-house Milli-Q water purification system (Millipore, Bedford, MA, USA) with a resistance >18 MΩ.cm −1 . Formic acid (≥98%) was obtained from Sigma-Aldrich. A 20 amino acid standard stock solution was made by dissolving individual L-amino acid standards (alanine, arginine, asparagine, aspartic acid, glutamic acid, glycine, glutamine, histidine, isoleucine, leucine, lysine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, valine, norvaline and alpha-aminobutyric acid) in Milli-Q water. The standards and MU samples were derivatized with 6-aminoquinolyl- N -hydroxysuccinimidyl carbamate (AQC) using the Waters AccQ•Tag kit (WAT052875, Waters, Milford, MA, USA). Briefly, 20 μL of standard/sample solution was buffered with 60 μL of 0.2 M borate, derivatized with 60 μL of AQC reagent solution, and centrifuged at 16,100 × g for 3 min to remove particles. The supernatant was dried with nitrogen gas and reconstituted into 30 μL of 5% acetonitrile in water. A 10-μL aliquot of this solution was injected into the column for ultra-high performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS) analysis. The UHPLC-MS/MS system consisted an Accela pump and Accela auto-sampler UHPLC system (Thermo Fisher Scientific, San Jose, USA) coupled with a TSQ Vantage triple quadrupole mass spectrometer (Thermo Fisher). UHPLC separation was carried out with an ACCQ-TAG TM ULTRA C18 column (100 × 2.1 mm, 1.7 μm particle size, Waters, Ireland) and a binary mobile phase (solvent A: 5% acetonitrile in water with 0.1% formic acid; solvent B: acetonitrile with 0.1% formic acid) delivered at a flow rate of 200 μL/min. The linear gradient elution program was as follows: 0.0 min − 0% B; 10.0 min − 5% B; 25.0 min − 15% B; 40.0 min − 22.5% B; 40.1 min − 80% B; 43.0 min − 80% B; 43.1 min − 0% B, and 50.0 min − 0% B. AQC derivatives of analytes were analyzed in positive ion detection mode using electrospray ionization and selected reaction monitoring (SRM) scan type. In order to improve the ion transmission efficiency, SRM scan time in the beginning of 40 min of LC gradient was divided into four time segments. Different SRM transitions and scan times in each time segment are list in Table S2 . Other MS instrument parameters were as follows: spray voltage (4000 V), vaporizer temperature (300 °C), capillary temperature (300 °C), sheath gas pressure (30 psi), ion sweep gas pressure (0 psi), auxiliary gas pressure (20 psi), S-lens (110 V), de-clustering voltage (−6 V) and argon collision gas pressure (1.0 mTorr), and collision energy (25 V).

E. coli adaptation to Control media

5-time concentrated M9 minimal salts stock solution was prepared by dissolving 42.5 g Na 2 HPO 4 . 2H 2 O, 15 g KH 2 PO 4 and 2.5 g NaCl in Milli-Q water to a final volume of 1000 mL. The solution was then sterilized by autoclaving at 121 °C for 20 min and stored at 4 °C for further use. M9 minimal media were prepared by mixing the following components: 800 mL Milli-Q water, 200 mL M9 concentrated salts stock solution, 2 mL of 1 M MgSO 4 solution, 0.1 mL of 1 M CaCl 2 solution, 1 g NH 4 Cl, 5 g mixture of DL-alanine and glycine (molar ratio 1:1). E. coli previously adapted to M9 minimal media was inoculated into 5 mL Control media and cultured at 37 °C for about 24 h. The optical density (O.D.) of the overnight culture exceeded 1.0. Each day, 5 μL overnight E. coli culture was diluted 1000 times by 5 mL fresh Control media and cultured at 37 °C continuously. In this way, nine to ten generations were grown between dilutions. The process continued for around three months, and ca. 800 generations adapted to Control media were obtained.

E. coli growth measurements

The MU mixture was sterilized by filtering through 0.2 μm membrane and further through a 10 kDa membrane filter before being used for bacteria growth. The overnight culture of E. coli adapted to Control media (O.D. ≈ 1.4) was diluted with Control media to reach O.D. ≈ 0.7. A 5 μL aliquot of the diluted E. coli culture (O.D. ≈ 0.7) was added into 35 mL Control media to obtain the diluted E. coli culture for sample preparation. The samples were prepared using a programmed robotic system (Tecan, Genesis RSP 150, Männedorf, Switzerland). The sample arrangements on the 100-well honeycomb plates are given in Figs S2 – 4 .

The BL21 strain of E. coli adapted to grow in a M9 minimal media containing glucose as the only source of carbon 18 was grown in a 100-well honeycomb plate designed for bacterial growth measurements. The plate contained multiple sample/standard pairs of wells filled with 270 (or 290) μL of Control media containing a 1:1 mixture of Gly and reacemized Ala as well as the same inorganic salts as in M9. To each of the sample well on the plate, 30 (or 10) μL of filtered MU mixture was added to the total volume of 300 μL, and to each control well—the same volume of either pure water or Control media ( Fig. S2 ).

Growth rate parameters were extracted as described in literature 18 . Briefly, the logarithm of O.D. was plotted against time. The slope for every 8-h interval was calculated, and the maximum value was determined as the maximum growth rate. The extrapolation of the line with maximum slope to the background level of O.D. gave the lag time. The maximum O.D. for each replicate minus the background O.D. was taken as the maximum density. The p-values were calculated using two-tailed, paired Student’s t-test.

Results and Discussion

Direct e. coli growth in mu mixture.

Usually, bacteria in a richer media exhibit shorter lag phase, faster maximum growth and achieve higher maximum density 18 . The first experiment with MU mixture yielded strikingly negative results. A small (≈3%) admixture of the MU mixture obtained after 5–8 days of MU experiment inhibited E. coli growth not only in sample wells, but also in control wells. The experiment was repeated three times, and each time no growth was observed even in the control wells containing no MU mixture. This result testifies to the high toxicity of the MU mixture, in agreement with the earlier concerns 14 . Apparently, toxic fumes spread from the sample wells across the 100-well plate. GC-MS analysis showed that the MU mixture contains such toxic components as hydrogen cyanide, cyanic acid, diethylamine, pyridine and allyl alcohol. Other dangerous compounds were also identified, e.g., methyl- and ethylamine, N,N-dimethylacetamide, formamide, butanedinitrile, and 1-methylpyrrolidinone-2 ( Table S1 ). GC-MS also detected presence of glycine and alanine, while heavier amino acids were not amenable to this technique.

In the fourth experiment, when a lighter 3 rd day MU fraction was used, some growth was observed, but it was strongly delayed ( Fig. S3 ). Even though the bacteria grown in sample wells eventually reached higher density than in the control wells, this result did not unequivocally verify the life-supporting properties of the MU mixture.

Adaptation of E. coli to MU mixture

To address the above issues, we pursued two strategies. First, we adapted the bacteria to grow in a synthetic mixture containing glycine and racemic alanine in equal proportions. Second, we dried and reconstituted the MU mixture, thus largely removing its volatile toxic components. To reach the first goal, the adapted to M9 minimal media E. coli strain BL21 was grown on (Gly + DL-Ala)-mixture supplemented with inorganic salts for ca. 800 generations (three months with daily media changes and reseeding). The adaptation progress was monitored with a BioScreen C automatic fermentor using the accurate method of growth parameter measurements 18 . Adaptation led to a 16% reduction in the lag phase duration, a 67% increase in the maximum growth rate as well as a 63% increase in the maximum density.

Then the MU mixture was dried in a SpeedVac, the solid residue reconstituted in the same volume of pure water, and the growth experiment was conducted with (Gly + DL-Ala)-adapted bacteria. This time addition of MU mixture produced evident boost of growth compared not only to the wells where pure water was added, but also compared to the wells containing 100% Control media ( Fig. 1 ).

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Top: sample layout. Bottom: examples of growth curves for different media: A − 97% Control mix + 3% reconstituted MU solution; B − 97% Control mix + 3% MiliQ water; C, D – 100% Control mix on two different 100-well plates.

The experiment was repeated twice, with very similar results: faster growth was found in all three domains of measurements ( Fig. 2 ). The strongest effect was a 20% reduction in the lag phase. This was not completely unexpected: while E. coli bacteria can grow on pure D-amino acids 17 , the presence of certain L-amino acids in the media can reduce their lag time significantly. Derivatization-assisted liquid chromatography separation of filtered MU mixture followed by mass spectrometric detection identified and quantified several biological amino acids. Besides the dominant Gly and Ala, Asn was detected ( Table 1 ), in full agreement with previous studies 7 , 9 , 10 . In a separate experiment, addition of 1 mg/L of L-Asn to M9 minimal media reduced the lag time of E. coli as much as the addition of 80 mg/L of D-Asn ( Fig. 3 ). This result confirmed that the presence of L-Asn was the likely cause of the growth acceleration effect of the dried MU mixture compared to Control media.

An external file that holds a picture, illustration, etc.
Object name is srep14338-f2.jpg

Sample − 97% Control mix + 3% reconstituted MU solution; Control – 100% Control mix; Standard – 97% Control mix + 3% MiliQ water. ( d–f ) Results of a replicate experiment.

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Object name is srep14338-f3.jpg

Amino Acids	Conc., ppm	Conc., %
Amino Acids	(n = 3)	(n = 3)
Gly	10.9 ± 0.6	55.4 ± 3.2
Ala	5.7 ± 0.4	28.9 ± 2.2
Abu	0.16 ± 0.04	0.8 ± 0.2
Ser	0.76 ± 0.04	3.9 ± 0.2
Pro	0.01 ± <0.01	0.07 ± <0.01
Val	0.01 ± <0.01	0.03 ± <0.01
NoVal	0.08 ± <0.01	0.39 ± 0.01
Thr	0.05 ± <0.01	0.23 ± 0.01
Asn	1.25 ± 0.02	6.4 ± 0.1
Asp	0.71 ± 0.04	3.6 ± 0.2
Glu	0.04 ± <0.01	0.19 ± 0.01
His	0.004 ± <0.001	0.02 ± <0.01
Arg	0.005 ± <0.001	0.02 ± <0.01
Trp	0.001 ± <0.001	0.004 ± <0.001

Abu—aminobutyric acid, NoVal—norvaline.

In the last experiment, bacteria were made to grow in pure reconstituted MU mixture, with addition of only inorganic salts. Strong growth detected in two replicates ( Fig. 4 ) leaves no doubt that dried and reconstituted primordial soup supports proliferation of E. coli adapted to a mixture of racemized simple amino acids.

An external file that holds a picture, illustration, etc.
Object name is srep14338-f4.jpg

Inorganic salts were added to all samples and controls.

Conclusions

Our experiments demonstrate that adapted bacteria can grow on reconstituted MU mixture as the only source of carbon. Bacterial adaptation as well as abiotic mixture drying and reconstitution in our experiments closely mimic the corresponding processes that are presumed to occur naturally on the early Earth. Ancient bacteria had millions of years to adapt to the available sources of carbon. The “cleansed” prebiotic soup could accumulate in well-aired large and small water pools, providing food for early life. Thus, our planet provided a hospitable environment for early life forms, regardless whether they spontaneously emerged on Earth or have arrived from outer space. The presence of the isotopic resonance in terrestrial isotopic compositions 21 , 22 was an additional advantage factor for early life.

It would be too simplistic to suggest that, because of the availability and even abundance on early Earth of accumulated prebiotically synthesized organic molecules, life must have originated on our planet from these compounds. Almost inevitably, early life would need to include rather unstable molecules that could not have accumulated in large quantities because of their short life time, such as RNAs. But it stands to reason that early metabolic machinery very quickly gained the ability to utilize the accumulated more stable compounds as a source of carbon and energy, simply because of their high abundance.

In interpreting the results of our study, it is important to remember that, on the one hand, modern organisms, such as E. coli , have arguably much more sophisticated metabolic machinery than primitive life forms. But on the other hand, the abundance of complex organic molecules in modern environment could have rendered the ability to process prebiotically synthesized simple organic compounds useless. Therefore, bacteria could have lost this ability in the process of evolution. Our experiment showed, however, that modern organisms can survive and thrive on a diet of prebiotically synthesized organic compounds. This ability might be the remnant of the early times when complex food was scarce on Earth. Therefore, early Earth would be a hospitable place for such organisms or their ancient counterparts, provided the latter had a similar metabolic competence.

If early life has come from other planets or star systems in a more or less developed form, as the panspermia hypothesis suggests, the abundance of primitive but edible food Earth provided for this early life might have been a decisive factor that determined its survival on our planet. One might also speculate that the type of easily available food had shaped the forms of life that have emerged and developed on Earth. However, there is currently not enough available knowledge to support such strong interpretation, in view of the RNA World and other competing hypotheses.

As a final comment, the Miller-Urey like synthesis analysed in this work was almost certainly complemented by the exogenous delivery of organics (e.g., kerogen-like polymers) by comets, meteorites and interplanetary dust particles entering Earth atmosphere. It is currently unknown whether this type of “imported” organics was edible. Further experiments are needed to clarify this issue.

Additional Information

How to cite this article : Xie, X. et al. Primordial soup was edible: abiotically produced Miller-Urey mixture supports bacterial growth. Sci. Rep. 5 , 14338; doi: 10.1038/srep14338 (2015).

Supplementary Material

Acknowledgments.

The authors thank Dr. Olga Polyakova and Dr. David Alonso for their help in sample preparation and conducting GC/MS experiments.

Author Contributions X.X. built the Miller-Urey apparatus, produced Miller-Urey mixture, supervised the bacterial experiments, performed bacterial experiments 5–6, and data analysis, created figures and wrote parts of the text. D.B. participated in bacterial experiments 1–4 and in data analysis. L.J. performed derivatization and LC-MS analysis of MU mixture; analyzed the resulting data; provided Table 1. L.L.I. supervised performing derivatization and LC-MS analysis of MU mixture; provided resources for this. A.T.L. participated in sample preparation and GC-MS analysis; provided GC-MS data interpretation. V.B.A. conducted sample preparation and GC-MS analysis. R.A.Z. planned the experiments, raised funding for MU- and bacterial experiments, participated in data analysis and wrote the main text. All authors contributed to text writing and editing.

Oparin A. I. The Origin of Life. (Dover Publications, Inc. 1965). [ Google Scholar ]
Bernal J. D. the physical basis of life . Proc. Phys. Soc. Sect. A 62 , 537 (1949). [ Google Scholar ]
Haldane J. B. S. in Sci. Hum. Life (Harper and Brothers, 1933). [ Google Scholar ]
Garrison W. M., Morrison D. C., Hamilton J. G., Benson A. A. & Calvin M. Reduction of carbon dioxide in aqueous solutions by ionizing radiation . Science 114 , 416–418 (1951). [ PubMed ] [ Google Scholar ]
Urey H. The Planets: Their origin and Development. 149–157 (Yale University Press, 1952). [ Google Scholar ]
Lewis R. Life. 153 (WCB McGraw-Hill, 1999). [ Google Scholar ]
Miller S. L. A production of amino acids under possible primitive earth conditions . Science 117 , 528–529 (1953). [ PubMed ] [ Google Scholar ]
Parker E. T. et al. Conducting miller-urey experiments . J. Vis. Exp. 83 , e51039 , doi: 10.3791/51039 (2014). [ PMC free article ] [ PubMed ] [ Google Scholar ]
Stanley M. L. Production of some organic compounds under possible primitive Earth conditions . J. Am. Chem. Soc. 77 , 2351–2361 (1955). [ Google Scholar ]
Johnson A. P. et al. The Miller volcanic spark discharge experiment . Science 322 , 404 (2008). [ PubMed ] [ Google Scholar ]
Jiang L. et al. Abiotic synthesis of amino acids and self-crystallization under prebiotic conditions . Sci. Rep. 4 , 6769, 10.1038/srep06769 (2014). [ PMC free article ] [ PubMed ] [ CrossRef ] [ Google Scholar ]
Lahav N. Biogenesis: Theories of Life’s Origin. (Oxford University Press, 1999). [ Google Scholar ]
Wells J. Icons of Evolution. (Regnery, 2000). [ Google Scholar ]
Bergman J. Why the Miller-Urey research argues against abiogenesis . J. Creat. 18 , 28–36 (2004). [ Google Scholar ]
Jamali F., Lovlin R., Corrigan B. W., Davies N. M. & Aberg G. Stereospecific pharmacokinetics and toxicodynamics of ketorolac after oral administration of the racemate and optically pure enantiomers to the rat . Chirality 11 , 201–205 (1999). [ PubMed ] [ Google Scholar ]
Coppedge J. F. Probability of left-handed molecules . CRSQ 8 , 163–174 (1971). [ Google Scholar ]
Kuhn J. & Somerville R. L. Mutant strains of Escherichia coli K12 that use D-amino acids . Proc. Natl. Acad. Sci. USA. 68 , 2484–2487 (1971). [ PMC free article ] [ PubMed ] [ Google Scholar ]
Xie X. & Zubarev R. A. Effects of low-level deuterium enrichment on bacterial growth . PLoS One 9 , e102071, 10.1371/journal.pone.0102071 (2014). [ PMC free article ] [ PubMed ] [ CrossRef ] [ Google Scholar ]
Peifer R. W. in Test. Stud. Lab. Teach. (ed. Goldman C. A. & Hauta P. L.) 43–67 (1993). [ Google Scholar ]
20.Polyakova O. V., Mazur D. M. & Lebedev A. T. Improved sample preparation and GC–MS analysis of priority organic pollutants . Environ. Chem. Lett. 12 , 419–427 (2014). [ Google Scholar ]
Zubarev R. A. et al. Early life relict feature in peptide mass distribution . Cent. Eur. J. Biol. 5 , 190–196 (2010). [ Google Scholar ]
Xie X. & Zubarev R. A. Isotopic Resonance Hypothesis: Experimental verification by Escherichia coli growth measurements . Sci. Rep. 5 , 9215, 10.1038/srep09215 (2015). [ PMC free article ] [ PubMed ] [ CrossRef ] [ Google Scholar ]

NOT EXACTLY ROCKET SCIENCE

Scientists finish a 53-year-old classic experiment on the origins of life

In 1958, a young scientist called Stanley Miller electrified a mixture of simple gases, designed to mimic the atmosphere of our primordial lifeless planet. It was a sequel to one of the most evocative experiments in history, one that Miller himself had carried five years earlier. But for some reason, he never finished his follow-up. He dutifully collected his samples and stored them in vials but, whether for ill health or dissatisfaction, he never analysed them.

The vials languished in obscurity, sitting unopened in a cardboard box in Miller’s office. But possessed by the meticulousness of a scientist, he never threw them away. In 1999, the vials changed owners. Miller had suffered a stroke and bequeathed his old equipment, archives and notebooks to Jeffrey Bada , one of his former students. Bada only twigged to the historical treasures that he had inherited in 2007. “Inside, were all these tiny glass vials carefully labeled, with page numbers referring Stanley’s laboratory notes. I was dumbstruck. We were looking at history,” he said in a New York Times interview .

By then, Miller was completely incapacitated. He died of heart failure shortly after, but his legacy continues. Bada’s own student Eric Parker has finally analysed Miller’s samples using modern technology and published the results, completing an experiment that began 53 years earlier.

Miller conducted his original 1953 experiment as a graduate student, working with his mentor Harold Urey. It was one of the first to tackle the seemingly insurmountable question of how life began. In their laboratory, the pair tried to recreate the conditions on early lifeless Earth, with an atmosphere full of simple gases and laced with lightning storms. They filled a flask with water, methane, ammonia and hydrogen and sent sparks of electricity through them.

The result, both literally and figuratively, was lightning in a bottle. When Miller looked at the samples from the flask, he found five different amino acids – the building blocks of proteins and essential components of life.

The relevance of these results to the origins of life is debatable, but there’s no denying their influence. They kicked off an entire field of research, graced the cover of Time magazine and made a celebrity of Miller. Nick Lane beautifully describes the reaction to the experiment in his book, Life Ascending : “Miller electrified a simple mixture of gases, and the basic building blocks of life all congealed out of the mix. It was as if they were waiting to be bidden into existence. Suddenly the origin of life looked easy.”

Over the next decade, Miller repeated his original experiment with several twists. He injected hot steam into the electrified chamber to simulate an erupting volcano, another mainstay of our primordial planet. The samples from this experiment were among the unexamined vials that Bada inherited. In 2008, Bada’s student Adam Johnson showed that the vials contained a wider range of amino acids than Miller had originally reported in 1953.

Miller also tweaked the gases in his electrified flasks. He tried the experiment again with two newcomers – hydrogen sulphide and carbon dioxide – joining ammonia and methane. It would be all too easy to repeat the same experiment now. But Parker and Bada wanted to look at the original samples that Miller had himself collected, if only for their “considerable historical interest”.

Using modern techniques, around a billion times more sensitive than those Miller would have used, Parker identified 23 different amino acids in the vials, far more than the five that Miller had originally described. Seven of these contained sulphur, which is either a first for science or old news, depending on how you look at it. Other scientists have since produced sulphurous amino acids in similar experiments, including Carl Sagan . But unbeknownst to all of them, Miller had beaten them to it by several years. He had even scooped himself – it took him till 1972 to publish results where he produced sulphur amino acids!

The amino acids in Miller’s vials all come in an equal mix of two forms, each the mirror image of the other. You only see that in laboratory reactions – in nature, amino acids come almost entirely in one version. As such, Parker, like Miller before him, was sure that the amino acids hadn’t come from a contaminating source, like a stray bacterium that had crept into the vials.

Imagine then, a young and violent planet, wracked with exploding volcanoes, noxious gases and lightning strikes. These ingredients combined to brew a “primordial soup”, fashioning the precursors of life in pools of water. On top of that, meteorites raining down from space could have added to the accumulating molecules. After all, Parker found that the amino acid cocktail in Miller’s samples is very similar to that found on the Murchison meteorite , which landed in Australia in 1969.

These are powerful images, so why aren’t people more excited? Echoing many sources I spoke to, Jim Kasting , who studies the evolution of Earth’s atmosphere, said, “I am underwhelmed by it.” The main problem with the study is that Miller was probably wrong about the conditions on early Earth.

By analysing ancient rocks, scientists have since found that Earth was never particularly teeming in hydrogen-rich gases like methane, hydrogen sulphide or hydrogen itself. If you repeat Miller’s experiment with a more realistic mixture – heavy in carbon dioxide and nitrogen, with just trace amounts of other gases – you’d have a hard time finding amino acids in the resulting brew.

Parker accepts the problem, but he suggests that a few specific places on the planet may have had the right conditions. Exploding volcanoes, for example, throw up masses of sulphurous compounds, as well as methane and ammonia. These gases, belched forth into lightning storms , could have produced amino acids that rained out and gathered in tidal pools. But Kasting still isn’t convinced. “Even then the reduced gases would not be as concentrated as they are in this experiment.”

Even if our young planet had the right conditions to produce amino acids, that’s a less impressive feat than it appeared in the 1950s. “Amino acids are old hat and are a million miles from life,” says Nick Lane. Indeed, as Miller’s experiments showed, it’s not difficult to create amino acids. The far bigger challenge is to create nucleic acids – the building blocks of molecules like RNA and DNA. The origin of life lies in the origin of these “replicators”, molecules that can make copies of themselves. Lane says, “Even if you can make amino acids (and nucleic acids) under soup conditions, it has little if any bearing on the origin of life.”

The problem is that replicators don’t spontaneously emerge from a mixture of their building blocks, just as you wouldn’t hope to build a car by throwing some parts into a swimming pool. Nucleic acids are innately “shy”. They need to be strong-armed into forming more complex molecules, and it’s unlikely that the odd bolt of lightning would have been enough. The molecules must have been concentrated in the same place, with a constant supply of energy and catalysts to speed things up. “Without that lot, life will never get started, and a soup can’t provide much if any of that,” says Lane.

Deep-sea vents are a better location for the origins of life. Deep under the ocean’s surface, these rocky chimneys spew out superheated water and hydrogen-rich gases. Their rocky structures contain a labyrinth of small compartments that could have concentrated life’s building blocks into dense crowds, and minerals that would have catalysed their get-togethers. Far away from visions of languid soups, these churning environments are the current best guess for the site of life’s hatchery.

So Miller’s iconic experiment, and its now-completed follow-ups, probably won’t lay out the first steps of life. As Adam Rutherford, who is writing a book on the origin of life, says, “It’s really a historical piece, like finding that Darwin had described a Velociraptor in one of his notebooks.”

If anything, the analysis of Miller’s vials is a testament to the value of meticulous scientific work. Here was a man who prepared his samples so cleanly, who recorded his notes so thoroughly, and who stored everything so carefully, that his contemporaries could pick up where he left off five decades later.

Reference: Parker, Cleaves, Dworkin, Glavin, Callahan, Aubrey, Lazcano & Bada. 2011. Primordial synthesis of amines and amino acids in a 1958 Miller H2S-rich spark discharge experiment. PNAS http://dx.doi.org/10.1073/pnas.1019191108

Photos by Carlos Gutierrez and Marco Fulle

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“Miller–Urey Experiment” in the Recent Picture of the Early Earth

First Online: 10 June 2018

Cite this chapter

Hiromoto Nakazawa 5

Part of the book series: Advances in Geological Science ((AGS))

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Traditional hypotheses on the origin of bioorganic molecules are reviewed. “Miller–Urey experiment” is looked again in the recent picture of the early Earth. The presently known cooling history of the early Earth suggests rather a reasonable mechanism of organic molecule formation; i.e., the “late heavy bombardment” (LHB) of meteorites at 4.0 ~3.8 b.y.a. would have led to the chemical conditions to produce a large amount of organic molecules on the Earth’s surface. Simulation experiments of meteorite impact to ocean have confirmed the phenomena of evaporation of rock-forming minerals and of a mass production of ammonia, a precursor of amino acid, in post-impact plume.

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The flask had a long S-shaped neck to avoid the incursion of bacteria, but allows the exchange of air. This type of flask was later referred to as a Pasteur flask or swan-necked flask.

An experimental result that several amino acids were synthesized even in the “oxidative” gas mixture of CO 2 , CO, N 2 , and H 2 O by irradiation with a proton beam was reported in 1990 (Kobayashi et al. 1990 ). However, since the proton, H + , acts chemically as a hydrogen ion, it should not be included as a case of oxidative conditions.

The classification of meteorites is described precisely in reference (Norton 2002 ). Meteorites are roughly divided as stony meteorites (93%), stony-iron meteorites (1%), and meteoritic iron (6%). The percentages in parentheses indicate the percentage of those types of meteorites collected so far.

The stony meteorite is further divided into chondrites (85%) containing chondrules (granular olivine and pyroxene) and acondrite (8%) not including chondrules. Chondrites are divided further into ordinary chondrites (81%) containing metallic iron or iron sulfides, carbonaceous chondrites (5%), containing neither iron nor iron sulfide, and E-chondrites (1.5%), especially rich in metallic iron (~25%).

Abe Y (2004) Birth of earth, planetary system (in Japanese). Tokyo University Press, Tokyo

Google Scholar

Bottke WF, Vokrouhlicky D, Minton D, Nesvorry D, Morbielli A, Brasser R, Simonson B, Levison HF (2012) An Archaean heavy bombardment from a destabilized extension of the asteroid belt. Nature 485:78–81

Article Google Scholar

Brandes JA, Boctor NZ, Cody GD, Cooper BA, Hazen RM, Yoder HS Jr (1998) Abiotic nitrogen reduction on the early Earth. Nature 395:365–367

Cohen BA, Swindle TD, Kring DA (2000) Support for the Lunar cataclysm hypothesis from Lunar meteorite impact melt ages. Science 290:1754–1755

Culler TS, Becker TA, Renne PR (2000) Lunar impact history from 40 Ar/ 39 Ar dating of glass spherules. Science 287:1785–1788

Darwin CR (1859) On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. John Murray, London

Dörr M, Käβboher J, Grunert R, Kreisel G, Brand WA, Werner RA, Geilmann H, Apfel C, Robl C, Weigard W (2003) A possible prfebiotic formation of ammonia from dinitrogen on iron sulfide surfaces. Angew Chem Int Ed 42:1540–1543

Egami F (ed) (1956) Origin of life and biochemistry (in Japanese). Iwanami, Tokyo, p. 24

Engel MH, Macko SA (1997) Isotropic evidence for extraterrestrial non-racemic amino acids in the Murchison meteorite. Nature 389:265–268

Engel MH, Nagy B (1982) Distribution and enantiometric composition of amino acids in the Murchison meteorite. Nature 296:837–840

Engels F (ed) (1956) Dialektik der Natur. Dietz Verlag, Berlin (1952); (Japanese translation by Tanabe, S., Iwanami, Tokyo)

Frei R, Rosing MT (2005) Search for traces of the late heavy bombardment on Earth—Results from high precision chromium isotopes. Earth Planet Sci Lett 236:28–40

Furukawa Y, Nakazawa H, Sekine T, Kakegawa T (2007) Formation of ultrafine particles from impact generated supercritical water Earth Planet. Sci Lett 258:543–549

Furukawa Y, Sekine T, Kakegawa T, Nakazawa H (2011) Impact-induced phyllosilicate formation from olivine and water. Geochim Cosmochim Acta 75:6461–6472

Gomes R, Levison HF, Tsigamism K, Morbidelli A (2005) Origin of the cataclysmic Late Heavy Bombardment period of the terrestrial planets. Nature 435:466–469

Harada K (1977) Origin of life, an approach from chemical evolution (in Japanese). University of Tokyo Press, pp 86–95

Hartmann WK, Ryder G, Dones L, Grinspoon D (2000) The time-dependent intense bombardment of the primordial Earth/Moon System. In: Canup RM, Righter K (eds) Origin of the earth and moon. University of Arizona Press, Tucson, pp 493–512

Hartmann WK, Ryder G, Dones L, Grinspoon D (2000b) The time-dependent intense bombardment of the primordial Earth/Moon system. In: Canup RM, Righter K (eds) Origin of the Earth and Moon. University of Arizona Press, Tucson, pp 493–512

Honma H (1996) High ammonium contents in the 3800 Ma Isua supracrustal rocks, central West Greenland. Geochim Cosmochim Acta 60:2173–2178

Ida S (2003) Variant Planets, From the Theory of Extrasolar Planetary Formation (in Japanese). NHK-book Co., Tokyo

Ida S, Kokubo E (1999) One billion earths—birth from stardust (in Japanese). Iwanami, Tokyo

Johnson BC, Melosh HJ (2012) Impact spherules as a record of an ancient heavy bombardment of Earth. Nature 485:75–77

Kasting JF (1990) Bolide impacts and the oxidation state of carbon in the Earth’s early atmosphere. Orig Life Evol Biosph 20:199–231

Kimoto K, Kamiya Y, Nonoyama M, Uyeda R (1963) An electron microscope study on fine metal particles prepared by evaporation in argon gas at low pressure. Jpn Appl Phys 2:702–713

Kobayashi K, Tsuchiya M, Oshima T, Yanagawa H (1990) Abiotic synthesis of amino acids and imidazole by proton irradiation of simulated primitive Earth atmospheres. Origin Life Evol Biosphere 20:99–109

Maruyama S, Isozaki Y (1998) Life and history of the earth. Iwanami, Tokyo, pp 20–22

Matsui T (1996) The differentiation, Chapter 3, in Introduction to earth and planetary science (in Japanese). In: ed. Tajika M, Yanagawa T, Iwanami A (eds), Tokyo

Matsui T, Abe Y (1986) Evolution of an impact-induced atmosphere and magma ocean on the accerating Earth. Nature 319:303–305

Miller SL (1953) A production of amino acids under possible primitive Earth condition. Science 117:528–529

Miller SL, Orgel LE (1974) The origin of life on the earth. Prentice-Hall Inc., Englewood Cliffs, New Jersey

Mojzsis SJ, Harison TM, Pigeon RT (2001) Oxygen-isotope evidence from ancient zircons for liquid water at the Earth’s surface 4,300 Myr ago. Nature 409:178–181

Nakazawa H, Sekine T, Kakegawa T, Nakazawa S (2005) High yield shock synthesis of ammonia from iron, water and nitrogen available on the early Earth. Earth Planet Sci Lett 235:356–360

National Astronomical Observatory of Japan (2001) Chronological scientific tables. Maruzen, Tokyo, p 167

Norton OR (2002) Summary of meteorites by classification, The Cambridge encyclopedia of meteorites. Cambridge University Press, Cambridge, pp 331–340

Onuma N (1987) Fascinated by cosmochemistry and geochemistry (in Japanese). Science House, Tokyo, pp 44–76 (Chaps. 3–4)

Oparin AI (1924) The origin of life, Proiskhozhdenie Zhizny, Moscow Izd. Moskovskii Rabochii (1924); Macmillan, London (1938)

Oparin AI (1957a) The origin of life on the earth. Oliver & Boyd, Edinburgh

Oparin AI (1957b) The origin of life on the earth. Academic Press, New York

Osaka T, Nakazawa H (1976) Cementite structure for iron sulfide, Ee3S. Nature 259:109–110

Pasteur L (1861) Sur les corpuscles organisès qui existent dans l’atmosphere: Examen de la doctrine des generations spontanées. Leçon Profeessée a la Sociétè Chimque de Paris

Pierazzo E, Melosh HJ (1999) Hydrocode modeling of Chicxulub as an oblique impact event. Earth Planet Sci Lett 165:163–176

Schoenberg R, Kamber BS, Collerson KD, Moobach S (2002) Tungsten isotope evidence from approximately 3.8-Gyr metamorphosed sediments for early meteorite bombardment of the Earth. Nature 418:403–405

Shimamura K, Shimojo F, Nakano A, Tanaka S (2016) Meteorite impact-induced rapid NH 3 production on early Earth: ab initio molecular dynamics simulation. Scientific Reports 6(38953)

Sleep NH, Zahnle KJ, Kasting JF, Morowitz HJ (1989) Annhilation of ecosystems by large asteroid impacts on the early Earth. Nature 342:139–142

Strom RG, Malhotra R, Ito T, Yoshida F, Kring DA (2005) The origin of planetary impactors in the inner solar system. Science 309:1847–1850

Urey HC (1952) The planets: their origin and development. Yale University Press, New Haven

Valley JW, Peck WH, King EM, Wilde SA (2002) A cool early Earth. Geology 30:351–354

Wethrill GW (1985) Occurrence of giant impacts during the growth of the terrestrial planets. Science 228:877–879

Wilde SA, Valley JW, Peck WH, Graham CM (2001) Evidence from detrital zircons for the existence of continental crust and oceans on the Earth 4.4 Gyr ago. Nature 409:175–178

Tera F, Papanastassiou DA, Wasserburg GJ: A lunar cataclysm at ~3.95 AE and the structure of the lunar crust. Lunar Science IV, The Lunar Science Inst., Houston, Texas, pp 723–725

Yin Q, Jacobson SB, Yamashita K, Blichert-Toft J, Telout P, Albarede F (2002) A short time scale for terrestrial planet formation from Hf-W chronometry of meteorites. Nature 418:949–955

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Nakazawa, H. (2018). “Miller–Urey Experiment” in the Recent Picture of the Early Earth. In: Darwinian Evolution of Molecules. Advances in Geological Science. Springer, Singapore. https://doi.org/10.1007/978-981-10-8724-0_4

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Miller-Urey experiment
The experiment. The Miller-Urey experiment (or Miller experiment) was an experiment in chemical synthesis carried out in 1952 that simulated the conditions thought at the time to be present in the atmosphere of the early, prebiotic Earth.It is seen as one of the first successful experiments demonstrating the synthesis of organic compounds from inorganic constituents in an origin of life ...
Miller-Urey experiment
The Miller-Urey experiment was an experimental simulation conducted in 1953 that tested whether organic molecules could be formed from chemical reactions occurring between inorganic molecules thought to have been present early in Earth's history. To test Oparin and Haldane's ideas, Miller and Urey designed a closed experiment in a laboratory.
Miller-urey Experiment
The Miller-Urey experiment fundamentally established that Earth ' s primitive atmosphere was capable of producing the building blocks of life from inorganic materials. In 1953, University of Chicago researchers Stanley L. Miller and Harold C. Urey set up an experimental investigation into the molecular origins of life.
Miller-Urey Experiment
The Miller-Urey Experiment was a landmark experiment to investigate the chemical conditions that might have led to the origin of life on Earth. The scientist Stanley Miller, under the supervision of the Nobel laureate scientist Harold Urey conducted it in 1952 at the University of Chicago. They tried to recreate the conditions that could have […]
Icon 1
u000bu000b. The Miller-Urey experiment represents one of the research programs spawned by the Oparin-Haldane hypothesis. Even though details of our model for the origin of life have changed, this has not affected the basic scenario of Oparin-Haldane. The first stage in the origin of life was chemical evolution.
Conducting Miller-Urey Experiments
In 1953, Stanley Miller reported the production of biomolecules from simple gaseous starting materials, using an apparatus constructed to simulate the primordial Earth's atmosphere-ocean system. ... The classic Miller-Urey experiment demonstrated that amino acids, important building blocks of biological proteins, can be synthesized using simple ...
Miller Urey Experiment: Hypothesis, Steps, Conclusions, and Limitations
The Miller-Urey experiment, conducted in 1953 by Stanley L. Miller and Harold C. Urey, aimed to simulate early Earth's conditions and test the Oparin-Haldane Hypothesis. Here are the key steps of the experiment: Simulating Early Earth's Atmosphere: The researchers recreated early Earth's atmosphere in a closed system using a mixture of ...
Hypotheses about the origins of life (article)
After letting the experiment run for a week, Miller and Urey found that various types of amino acids, sugars, lipids and other organic molecules had formed. Large, complex molecules like DNA and protein were missing, but the Miller-Urey experiment showed that at least some of the building blocks for these molecules could form spontaneously from ...
Miller-Urey Experiment
How was the Miller-Urey Experiment conducted? In the Miller-Urey Experiment, Stanley Miller and Harold Urey created a closed system that mimicked the conditions of early Earth's atmosphere. They used a mixture of gases such as methane, ammonia, hydrogen, and water vapor, which were believed to be present in the atmosphere of early Earth. The ...
Oparin-Haldane theory
In 1953 American chemists Harold C. Urey and Stanley Miller tested the Oparin-Haldane theory and successfully produced organic molecules from some of the inorganic components thought to have been present on prebiotic Earth. This became known as the Miller-Urey experiment.Modern abiogenesis hypotheses are based largely on the same principles as the Oparin-Haldane theory and the Miller-Urey ...
Teach Astronomy
The Miller-Urey experiment. The original apparatus used by Miller and Urey was quite simple compared to today's standards. It essentially consisted of two glass flasks connected by glass tubing. One flask served as the boiling flask, where gases and other molecules could accumulate in a water phase. The other flask (located above the boiling ...
The Miller-Urey Experiment
Explore LearningMedia Resources by Subject. Learn how amino acids, important building blocks of life, may have originated on Earth in this video from NOVA: Life's Rocky Start. Use this resource to stimulate thinking about the origin of life and to provide opportunities to make evidence-based claims.
Miller and Urey
Miller and Urey. The 1953 experiment of Miller and Urey was a watershed in "origin of life" research. It showed that under conditions that simulated the early Earth, amino acids and other biologically relevant molecules could be synthesized from inorganic starting materials in the laboratory. Animation of the spark-discharge experiment.
Miller-Urey Revisited
One of the unpublished experiments by American chemist Stanley Miller (under his University of Chicago mentor, Nobelist Harold Urey) actually produced a wider variety of organic molecules than the experiment that made Miller famous. The difference between the two experiments is small — the unpublished experiment used a tapering glass ...
Planet Earth/7c. How did Life Originate?
The Miller-Urey Experiment. Miller begin by recreating small lab versions of the atmosphere and ocean of the early Earth, which he knew from geological evidence was anoxic, lacking free oxygen gas. ... These more complex molecules required an additional input of energy and raw materials as well as different processes. It is still a mystery what ...
The Miller Urey Experiment
The Miller Urey Experiment. In the 1950's, biochemists Stanley Miller and Harold Urey, conducted an experiment which demonstrated that several organic compounds could be formed spontaneously by simulating the conditions of Earth's early atmosphere. They designed an apparatus which held a mix of gases similar to those found in Earth's early ...
Miller-Urey Experiment
In essence, the Miller-Urey experiment fundamentally established that Earth's primitive atmosphere was capable of producing the building blocks of life from inorganic materials. In 1953, University of Chicago researchers Stanley L. Miller and Harold C. Urey set up an experimental investigation into the molecular origins of life.
A Brief Explanation Of Miller Urey Experiment
Miller and Urey Experiment. Stanley L. Muller and Harold C. Urey performed an experiment to describe the origin of life on earth. They were of the idea that the early earth's atmosphere was able to produce amino acids from inorganic matter. The two biologists made use of methane, water, hydrogen, and ammonia which they considered were found ...
Miller Urey Experiment: Definition & Results
Miller-Urey Experiment Results. After running for a week, the liquid simulating the ocean inside their apparatus turned a brownish-black color. Miller and Urey's analysis of the solution showed complex stepwise chemical reactions had occurred forming simple organic molecules, including amino acids - proving organic molecules could form under the conditions laid out in the Oparin-Haldane ...
Primordial soup was edible: abiotically produced Miller-Urey mixture
Miller-Urey experiment marked the beginning of a new scientific field - prebiotic chemistry 12; it is now the most commonly cited evidence for abiogenesis in science textbooks 13. Yet sixty years after this seminal experiment, the debate is still ongoing whether it represents a definite argument for spontaneous life emergence, or even whether ...
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Miller conducted his original 1953 experiment as a graduate student, working with his mentor Harold Urey. It was one of the first to tackle the seemingly insurmountable question of how life began ...
"Miller-Urey Experiment" in the Recent Picture of the Early Earth
At the time, Miller was a graduate student at the University of Chicago, USA, and the composition of the mixed gas had been suggested by his supervisor, H. C. Urey (Urey 1952). Urey was a chemist who discovered deuterium (an isotope of hydrogen, 2 H) at the age of 38 and was consequently awarded the Nobel Prize at the very young age of 41.
Stanley Miller
Stanley Lloyd Miller (March 7, 1930 - May 20, 2007) was an American chemist who made important experiments concerning the origin of life by demonstrating that a wide range of vital organic compounds can be synthesized by fairly simple chemical processes from inorganic substances. In 1952 he performed the Miller-Urey experiment, which showed that complex organic molecules could be ...

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Table of Contents

Miller Urey Experiment: Hypothesis, Steps, Conclusions, and Limitations

Oparin-Haldane Hypothesis

Steps of the Miller Urey Experiment

Conclusions of the Miller Urey Experiment

Limitations of the Miller Urey Experiment

Ongoing Debates and Significance

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Hypotheses about the origins of life

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Introduction

From inorganic compounds to building blocks

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Miller-Urey Experiment – Definition & Detailed Explanation – Astrobiology Glossary

What is the Miller-Urey Experiment?

How was the Miller-Urey Experiment conducted?

What were the key findings of the Miller-Urey Experiment?

What impact did the Miller-Urey Experiment have on the field of Astrobiology?

How has the Miller-Urey Experiment influenced our understanding of the origins of life on Earth?

What are some criticisms of the Miller-Urey Experiment?

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Chapter 18: Life On Earth

Chapter 2 Early Astronomy

Chapter 3 The Copernican Revolution

Chapter 4 Matter and Energy in the Universe

Chapter 5 The Earth-Moon System

Chapter 6 The Terrestrial Planets

Chapter 7 The Giant Planets and Their Moons

Chapter 8 Interplanetary Bodies

Chapter 9 Planet Formation and Exoplanets

Chapter 10 Detecting Radiation from Space

Chapter 11 Our Sun: The Nearest Star

Chapter 12 Properties of Stars

Chapter 13 Star Birth and Death

Chapter 14 The Milky Way

Chapter 15 Galaxies

Chapter 16 The Expanding Universe

Chapter 17 Cosmology

Chapter 18 Life On Earth

Miller-Urey Experiment

Chapter 19 Life in the Universe

Miller-Urey Revisited

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