ORIGINS: UNIVERSE, LIFE, HUMANKIND, AND DARWIN

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ORIGINS: UNIVERSE, LIFE, HUMANKIND, AND DARWIN

We debate origins of the Universe, life, Earth, humans, religion, atheism, using common sense, evolution, cosmology, geology, archaeology, and other sciences, to repel biblical creationism and other religious beliefs.

Location: Oxford University, England
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Latest Activity: 29 minutes ago

The portrait is Charles Darwin, age 31, in 1840

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Discussion Forum

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Comment by gerry gallacher on September 1, 2011 at 9:43am
Many thanks to all who supplied answers to my question...well appreciated.
Comment by Ezra David Rose on August 31, 2011 at 2:06pm

@Justin

 

On the subject of whether or not polypeptides have a function on their own, keep in mind that polypeptides are largely what enzymes and coenzymes tend to be. And you basically pointed this out where you said: "There is some very interesting chemistry on using simple polypeptides as catalysts for different chemical reactions." By saying that, you basically illustrated the exact function of enzymes and coenzymes.

Comment by Justin on August 31, 2011 at 9:22am

I believe that the main indictment of protein evolution is that short polypeptides (e.g., protein fragments made up of a few amino acids) don't have function on their own, and therefore it is difficult to imagine how they would exert any selection pressure for future generations that would cause them to develop further.  This is a little bit of a strawman since the claim isn't that proteins have to suddenly have a fully developed function from day one is not made by scientists.  All you really need to get is a self-replicating molecule or one that promotes some change in the surrounding environment that is advantageous (say, by sequestering a harmful pollutant).  There is some very interesting chemistry on using simple polypeptides as catalysts for different chemical reactions, which I believe provides a sound basis for the idea that even simple polypeptides can have useful properties, but some gaps still need to be filled in.  Another factor is that complexity of polypeptides grows very rapidly once you start assembling fragments of three or four amino acids to one another.  They don't have to be built up one amino acid at a time, and therefore you have access to a big diversity of polypeptides in fewer steps.

 

There is also the question of how formed proteins can evolve in ways that require two or more "random" site mutations (i.e., where two parts of a protein must change "simultaneously" to give the positive effect).  This one has been debunked by the science now.  The basic idea is that one site mutation might not have a positive effect, but it also might not have a significant negative effect to select against it, so it could be carried forward into future generations (no selection pressure).  Then, when the second mutation comes along, the positive effect manifests and you have your advantage.

Comment by Ezra David Rose on August 30, 2011 at 4:10pm
Bachman, the one person who Palin may not even hold a candle to in the world of powerful fu$king stupid. But then again.....
Comment by Marc Draco on August 30, 2011 at 2:30pm

UK broadcaster BBC has amongst its headline today, "The evolution of 9/11 conspiracy theories".

 

How cool would it be for a Michell Bachman to say that evolution was a lie in response to that!

Comment by Ezra David Rose on August 30, 2011 at 1:17pm

@Gerry and Marc:

 

Well yes, the evolution of proteins in its self is the result of natural selection. The proponents of "intelligent design" on the Texas Board of Education tried to make arguments based on similar ideas in order to alter high school text books. Ultimately they embarrassed themselves as usual.

Comment by Marc Draco on August 30, 2011 at 12:19pm

Indeed - this is an interesting theory, Bob. One I've considered many times when pondering why Miller-Ulrey never quite delivered on its promise. How wonderfully ironic if the conditions on Earth were never quite right for abiogenesis - but that pre-life actually formed elsewhere first and just happened to take hold here.

 

I love science, me.

Comment by Bob on August 30, 2011 at 9:21am

Re;

Mr. Gallacher's Evolution of proteins quandary, has heard of or read "Darwin's God" Blog.

 

Then there is the idea of "Strong Panspermia" where protiens came to Earth from outer space

Comment by Marc Draco on August 30, 2011 at 8:32am

Gerry, by |debunk Natural Selection", do you actually mean, debunks creation/creationism?

 

Natural selection is part and parcel of evolution - selection (by survival and inheritance) of the organisms best adapted to the current conditions.

Comment by gerry gallacher on August 30, 2011 at 8:18am
Can anyone give me a heads up on the evolution of protiens please...I know there are very intelligent people here who can simplify this argument that protien evolution debunks natural selaction.
 

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