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Author Topic:   Miller and Urey Experiment: What has changed?
Ardent Enthusiast
Inactive Member


Message 1 of 85 (303401)
04-12-2006 12:04 AM


Hi all,
Listen, I'm new to EvC, so be easy on me, alright?
In my AP Bio class, we went through the origin of life on earth, how lightening struck chemicals on primordial earth, and how amino acids were formed and these became the first proteins and nucleic acids which eventually became the first Prokaryotic cell, etc. This theory was based on the Miller/Urey experiment, which took place in 1953. My question is, why hasn't any new data been gathered on this topic, and if it has, why is it still being taught at the high school/college level?
Replies to this message:
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 Message 5 by PaulK, posted 04-12-2006 3:20 AM Ardent Enthusiast has not yet responded

  
AdminNosy
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Message 2 of 85 (303410)
04-12-2006 12:56 AM


Thread moved here from the Proposed New Topics forum.
  
Percy
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From: New Hampshire
Joined: 12-23-2000
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Message 3 of 85 (303417)
04-12-2006 2:10 AM
Reply to: Message 1 by Ardent Enthusiast
04-12-2006 12:04 AM


Ardent Enthusiast writes:

This theory was based on the Miller/Urey experiment, which took place in 1953. My question is, why hasn't any new data been gathered on this topic, and if it has, why is it still being taught at the high school/college level?

While there's still nearly as much uncertainty today as a half century ago, the field *has* progressed a great deal since then. This seems like a perfect description of 50 year-old thinking:

In my AP Bio class, we went through the origin of life on earth, how lightening struck chemicals on primordial earth, and how amino acids were formed and these became the first proteins and nucleic acids which eventually became the first Prokaryotic cell, etc.

This makes me very curious about the materials being used in your AP biology class. Could you scan these materials in and make them available to us here?

To try to briefly answer your question, while nothing in that description is necessarily wrong, it doesn't really accurately reflect modern thinking on the orgin of life on earth. It happened nearly 4 billion years, and after all that time there is very little evidence. Research since Miller/Urey has been very active and come quite a long ways, but we still know very little. Modern speculation on the subject is very circumspect, and no recent responsible presentation would offer a simplistic scenario like the one you described without making clear that it's just a very simplified and speculative summary of one possibility for abiogenesis (origin of life).

--Percy


This message is a reply to:
 Message 1 by Ardent Enthusiast, posted 04-12-2006 12:04 AM Ardent Enthusiast has responded

Replies to this message:
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Modulous
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Message 4 of 85 (303423)
04-12-2006 3:00 AM
Reply to: Message 1 by Ardent Enthusiast
04-12-2006 12:04 AM


In my AP Bio class, we went through the origin of life on earth, how lightening struck chemicals on primordial earth, and how amino acids were formed and these became the first proteins and nucleic acids which eventually became the first Prokaryotic cell, etc. This theory was based on the Miller/Urey experiment, which took place in 1953

Normally the Miller/Urey experiment is presented as it should be: an experiment to demonstrate that organic molecules can be formed abiotically (without life). It gets mentioned a lot because it was the first/most succesful experiment to create amino acids in the labarotary using what was thought to be early earth conditions.

My question is, why hasn't any new data been gathered on this topic, and if it has, why is it still being taught at the high school/college level?

Since then, plenty has happened, as Percy indicated above. I'm not aware of what exactly is being taught in High Schools in New York, but it doesn't get a lot of class time at the lower end of biological study for two reasons that strike me:

1. Its a terribly complicated subject that would require a lot of background knowledge – more time than is available.

2. The exact nature of the origin of life is unknown. There are a number of different hypothesis. All of them quite complex; each one should be discussed, even less time to do this!

That said, I believe some high schools have involved kids making their own proteinoid microspheres (which some refer to as proto-cells), since the experiment is very easy to carry out.


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PaulK
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Message 5 of 85 (303425)
04-12-2006 3:20 AM
Reply to: Message 1 by Ardent Enthusiast
04-12-2006 12:04 AM


My understanding of the current situation is:

There is still uncertainty about the composiiton of the atmosphere of the early Earth. It may have had a composition that would rule out Urey-Miller synthesis of amino acids. More likely, though the atmosphere did permit Urey-Miller synthesis and it was a significant source of amino acids.

There has been a huge amount of work on later stages. One of the major discoveries was that RNA could work as a catalyst as well as a template for replication. This solved a major problem with the early stages of life because the same substance could perform two roles crucial to life, and it is now thought that DNA-based life developed from earlier RNA-based life.

There's a lot more but I'll leave that to people who are better informed


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Ardent Enthusiast
Inactive Member


Message 6 of 85 (303655)
04-12-2006 7:27 PM
Reply to: Message 3 by Percy
04-12-2006 2:10 AM


Hi Percy,
I do not have a scanner. I do know people who do, however, and I will scan some pages as soon as I can.
In the meantime, here's the passage I was referring to.
In the 1950's, American chemists Stanley Miller and Harold Urey tried to answer that question by simulating conditions on the early Earth in a laboratory setting. They filled a flask with hydrogen, methane, ammonia, and watter to represent the atmosphere. They made certain that no microorganisms could contaminate the results.Then, they passed electric sparks through the mixture to simulate lightening.
The results were spectacular. Over a few days, several amino acids-the building blocks of proteins-began to accumulate. Miller and Urey's experiments suggested how mixtures of the organic compounds necessary for life could have arisen from simpler compounds present on a primitive Earth.

This book was written by Ken Miller and Joe Levine by the way.
Anyway, what is this experiment doing in a 2006 Biology book? Especially alone in a 2006 Biology book. There is no mention of any other experiments relating to life on early Earth in this book. Does that mean there are no such experiments? If not, why are'nt they in the text? If so, why have these experiments not been performed?
This message is a reply to:
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 Message 8 by RAZD, posted 04-12-2006 9:53 PM Ardent Enthusiast has not yet responded
 Message 9 by Percy, posted 04-13-2006 9:19 AM Ardent Enthusiast has not yet responded

  
Matt P
Member (Idle past 2156 days)
Posts: 106
From: Tampa FL
Joined: 03-18-2005


Message 7 of 85 (303675)
04-12-2006 8:06 PM
Reply to: Message 6 by Ardent Enthusiast
04-12-2006 7:27 PM


It's the most well-known experiment
There is a whole journal devoted to origins of life studies ranging from experiments similar to the Miller-Urey experiment to completely different from these experiments. The journal is entitled "Origins of Life and Evolution of Biospheres." Other experiments have been reported in journals like Science and Nature, Geochimica et Cosmochimica Acta, the Journal of Molecular Evolution, and Astrobiology. I believe that a bibliography of experiments related to origins of life studies (presented in the journal Origins of Life...) from the early 1980s listed about 1000 papers on this subject. Since then, the field has continued to grow.

I would say that your textbook is neglecting these experiments mainly because to discuss them in depth would require a full class on its own. That's not really possible, and not really necessary for understanding general biology. The Miller-Urey experiment is commonly quoted since it was one of the first experimental evidences for the production of organic compounds, and it was one of the easiest means of producing organics. The book is likely just discussing the key experiment that laid the experimental framework for many future origins of life studies. I think it's probably akin to discussing Darwin's finches as evidence for evolution.

It is probably true that your book should have a follow-up sentence along the lines of "Experiments performed after the Miller-Urey experiment have further confirmed the production and chemical evolution of organic compounds through abiotic means." Still, textbooks aren't easy to write, and the authors aren't origins of life researchers.


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RAZD
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Message 8 of 85 (303715)
04-12-2006 9:53 PM
Reply to: Message 6 by Ardent Enthusiast
04-12-2006 7:27 PM


Another reason that new research is not included in new textbooks is that it takes some time for new stuff to make it past the editors and the schoolboard textbook selection committees ...

This thread {Building Blocks} (column) is an overview of the current state of understanding that I put together. It might give you some leads.


www.evcforum.net/cgi-bin/dm.cgi?action=msg&f=14&t=1157&m=1>Join the effort to unravel {AIDS\HIV} with Team EvC! (click)

we are limited in our ability to understand
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RebelAAmerican.Zen[Deist
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Percy
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Posts: 15561
From: New Hampshire
Joined: 12-23-2000
Member Rating: 4.3


Message 9 of 85 (303826)
04-13-2006 9:19 AM
Reply to: Message 6 by Ardent Enthusiast
04-12-2006 7:27 PM


Ardent Enthusiast writes:

I do not have a scanner. I do know people who do, however, and I will scan some pages as soon as I can.

That'd be great. Keep in mind that the passage from your opening post that made me curious about these materials was this one:

Ardent Enthusiast in Message 1 writes:

In my AP Bio class, we went through the origin of life on earth, how lightening struck chemicals on primordial earth, and how amino acids were formed and these became the first proteins and nucleic acids which eventually became the first Prokaryotic cell, etc.

The reason this caught my attention is that while high school biology classes are not the proper place to get into the nuances of modern conceptions of abiogenesis, it would still be misleading to present the above scenario as if it were something we were pretty sure of. And it would be surprising if the source were a book with Ken Miller's name on the cover.

Anyway, what is this experiment doing in a 2006 Biology book? Especially alone in a 2006 Biology book. There is no mention of any other experiments relating to life on early Earth in this book.

The Miller/Urey experiment was landmark! Historic! Revolutionary! It changed our thinking about life's orgins. You can only discover this new scientific paradigm once. Miller/Urey is in the same class of experiments as Galileo's falling objects experiment at the Leaning Tower of Pisa, the Michelson/Morley experiment that showed the ether didn't exist, the Millikan oil drop experiment that revealed the charge of the electron, and the Eddington measurements of starlight deflection during an eclipse that provided confirmation of Einstein's general theory of relativity.

There were subsequent experiments in all these cases, but the ones that get mentioned time and again, the ones that are remembered, are the ones that first changed our thinking and let man's understanding of the universe take another step forward.

You can use Google (and Google Scholar if you're of a technical bent) to find scads of information about subsequent work in abiognesis. There are also some good books, including a very recent one that is a survey of recent abiogenesis research called Gen-e-sis: The Scientific Quest for Life's Origins by Robert Hazen.

--Percy

This message has been edited by Percy, Thu, 04-13-2006 09:20 AM


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AdminNosy
Administrator
Posts: 4751
From: Vancouver, BC, Canada
Joined: 11-11-2003


Message 10 of 85 (407510)
06-26-2007 2:22 PM


Bump for pbee
Just to bring this up for Pbee to add his disprove using scientific methods.

See Message 69


  
Chiroptera
Member
Posts: 6227
From: Oklahoma
Joined: 09-28-2003
Member Rating: 4.1


Message 11 of 85 (407652)
06-27-2007 1:22 PM


I, too, bump for pbee.
Hey, pbee, didn't you boast that you were going to trash the Urey-Miller experiment? Yes, you did.


Actually, if their god makes better pancakes, I'm totally switching sides. -- Charley the Australopithecine
  
LimpSpider
Member (Idle past 1562 days)
Posts: 96
Joined: 09-27-2012


Message 12 of 85 (674198)
09-27-2012 2:21 AM


There has to be energy to form these amino acids. Hence the lightning. No new data has been released because no new successful experiment has been conducted. (Itís not the fault of the scientists, they tried hard)

Hereís what I donít like about the Miller-Urey experiment. It does not use the whole spectra of the UV range. It uses a specific wavelength to produce the amino acids and left out all the rest. (Which would have been harmful to the amino acids. Part of the reason why UV light is used to kill bacteria in hospitals.).

It also had traps to remove the product before it is destroyed by radiation. Not something found in the natural world. (The ocean would not have protected the amino acids in a natural enviroment. UV light can penetrate several meters)

Also, presumed conditions of primordial earth would have driven the amino acids toward lonely isolation. Hence any formation of proteins would have been subverted. There is also a strong tendency for peptide bonds to break down in water.

In addition to this, there is something known as the ďchirality problemĒ. With rare exceptions, all bio-molecules of amino acids are left-handed, and those of sugars are right-handed.

Racemates are mixtures artificially created that have a 50:50 ratio of right and left-handed.

Edited by Adminnemooseus, : Blank lines.


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Dr Adequate
Member
Posts: 15766
Joined: 07-20-2006
Member Rating: 3.1


Message 13 of 85 (674234)
09-27-2012 8:57 AM
Reply to: Message 12 by LimpSpider
09-27-2012 2:21 AM


No new data has been released because no new successful experiment has been conducted.

The fact that you made this up kinda vitiates your argument.

Given that, I would like to see references for everything else in your post.


This message is a reply to:
 Message 12 by LimpSpider, posted 09-27-2012 2:21 AM LimpSpider has responded

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LimpSpider
Member (Idle past 1562 days)
Posts: 96
Joined: 09-27-2012


Message 14 of 85 (674240)
09-27-2012 9:33 AM
Reply to: Message 13 by Dr Adequate
09-27-2012 8:57 AM


Simple question. What experiment has been conducted that expands successfully (as in the direction towards making life) Millerís original experiment? Can I provide the references tomorrow? Itís night here.
This message is a reply to:
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Percy
Member
Posts: 15561
From: New Hampshire
Joined: 12-23-2000
Member Rating: 4.3


Message 15 of 85 (674247)
09-27-2012 10:10 AM
Reply to: Message 14 by LimpSpider
09-27-2012 9:33 AM


For a few directly related references, check out Recent Related Studies over at the Wikipedia article on the Miller/Urey experiment. For a much broader view of work on abiogenesis try the Wikipedia article on Abiogenesis.

--Percy


This message is a reply to:
 Message 14 by LimpSpider, posted 09-27-2012 9:33 AM LimpSpider has responded

Replies to this message:
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