The Miller-Urey experiment was basically an experiment that supposedly stimulated the conditions of the early earth, and showed how Amino Acids the basic molecules of life could form spontaneously.
This experiment, however, was proven wrong later when it was discovered that they had used the wrong gases, which was why they had received such favorable results. When it was repeated with the correct gases, it did not work. This is why it was shunned, and why I assume it is controversial.
In general though, you should always be ready to expect lots of controversy when you get to the field of origin theory. While it often means easy grades for Biology class, you should be ready for a lot of arguments and controversy if you want to do some formal work on this topic. If you have a grievance concerning the content or argument of the Editorial Board, please contact either Opinion Editor Peyton Hamel peyton. Those wanting to respond to editorials can also submit a letter to the editor through the Iowa State Daily website or by emailing the letter to Opinion Editor Peyton Hamel peyton.
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This collection features the arguments in favor of and against the renaming of Catt Hall on Iowa State's campus, which was named in …. Edit Close. Toggle navigation. Opinion Policies Editorials are longer opinion pieces that are written by a group of community members recruited across campus who address relevant issues on a local, national and international level. 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. They are irrelevant, as chemical data suggest that life arose 3. 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, 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, 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.
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. 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.
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. 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 , 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. 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.
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