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Author Topic:   Problems with evolution? Submit your questions.
abrown9
Junior Member (Idle past 3239 days)
Posts: 8
From: Thunder Bay, Ontario, Canada
Joined: 08-20-2010


Message 101 of 752 (575553)
08-20-2010 12:58 PM
Reply to: Message 88 by Bolder-dash
08-20-2010 3:34 AM


There are some experiments, however, that do show how selective pressures work to influence the genome. The results of these experiments can lend weight to certain predictions.

I know there was one experiment (I've searched and failed to find the link), where viruses were grown in an media containing all of the necessary amino acids for life. After many generations, pathogenic and other extraneous genes had been shed (through random mutation and selective pressure) in favour of an extremely small genome optimized for replication. Darwinian theory of evolution would suggest that organisms with higher replicating rates will prosper in areas with abundant resources. This experiment lends weight to that prediction.


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abrown9
Junior Member (Idle past 3239 days)
Posts: 8
From: Thunder Bay, Ontario, Canada
Joined: 08-20-2010


Message 113 of 752 (575702)
08-20-2010 8:51 PM
Reply to: Message 105 by Dr Adequate
08-20-2010 7:40 PM


quote:
Surely these must have been bacteria, not viruses. This might help you to find the link

No, I'm pretty sure it was viruses. Bacterial DNA has a lot more proofreading mechanisms built in than viral RNA, so experiments with viral RNA would likely be more time-efficient to fully show the extent of 'evolution'.

And I actually just found it..it had to do with QB viral RNA: http://books.google.ca/books?id=ESXrX3H4KnIC&pg=PA236&dq=...


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abrown9
Junior Member (Idle past 3239 days)
Posts: 8
From: Thunder Bay, Ontario, Canada
Joined: 08-20-2010


Message 114 of 752 (575704)
08-20-2010 8:55 PM
Reply to: Message 112 by Bolder-dash
08-20-2010 8:47 PM


See above link.. that clearly shows that within 72 generations, a "population" of viral RNA evolved to optimize to its conditions. This occurred through mutation and natural selection. Even better, the study directly relates to the "creation of life", because it deals essentially with replicons, the earliest forms of "life" that would have cropped up. The true first self-replicating molecules would likely be significantly smaller than these, however.

There are also theoretical computer models that will map the 'evolution' of digital, higher lifeforms. Obviously these kind of experiments would be impossible to perform on actual animal populations due to the massive evolutionary time frame we would be looking at.

Edited by abrown9, : adding information


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abrown9
Junior Member (Idle past 3239 days)
Posts: 8
From: Thunder Bay, Ontario, Canada
Joined: 08-20-2010


Message 118 of 752 (575718)
08-20-2010 9:38 PM
Reply to: Message 117 by Dr Adequate
08-20-2010 9:24 PM


Well clearly that shows that the link probably didn't exist!

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abrown9
Junior Member (Idle past 3239 days)
Posts: 8
From: Thunder Bay, Ontario, Canada
Joined: 08-20-2010


Message 155 of 752 (575954)
08-21-2010 9:47 PM
Reply to: Message 151 by dennis780
08-21-2010 8:11 PM


I would argue that it is totally irrelevant whether the mutated organism survives in the wild or reverts to wild type. The environment of the organism exerts selective pressure, directing mutations. It would seem fairly obvious that a WILD environment would exert selective pressure towards the WILD type.

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abrown9
Junior Member (Idle past 3239 days)
Posts: 8
From: Thunder Bay, Ontario, Canada
Joined: 08-20-2010


Message 169 of 752 (576068)
08-22-2010 5:44 PM
Reply to: Message 162 by dennis780
08-22-2010 1:05 PM


Sorry Dennis, I don't think you grasped what I was trying to say. Controlled laboratory experiments are exactly that, controlled experiments. Mutations that are selected for in controlled environments will be beneficial for animals in controlled environments, but not necessarily for animals in the wild.

It's virtually impossible to perform an experiment that will imitate ex vitro conditions, so it seems unlikely that a laboratory experiment could produce a mutant optimized to survive and flourish in nature.

The only suitable organisms for these kind of experiments are unicellular, viral, or RNA species. If you can find a way to completely mimic natural conditions (or perform an experiment ex vitro), then you have a good career ahead of you. There are untold millions of bacterial species that can act in synergistic or antagonistic manners towards the species you wish to study. To fully account for all of the variables is impossible.

What these experiments do demonstrate, however, is the fact that EVOLUTION TAKES PLACE. Just because it is observed in a lab does not make it any less real.


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abrown9
Junior Member (Idle past 3239 days)
Posts: 8
From: Thunder Bay, Ontario, Canada
Joined: 08-20-2010


Message 226 of 752 (578020)
08-31-2010 2:11 PM
Reply to: Message 210 by dennis780
08-29-2010 11:20 PM


I`m not exactly sure what kind of studies you are hoping (or rather not hoping) we can produce to answer your questions about `gains in information`and beneficial mutations. Do you want to see an experiment that documents the transition of one species to another, carefully documenting each beneficial mutation along the way? If that's the only way we can "win" the debate, then I guess you are in luck because (as far as I know), no such experiments exist.

What do exist, however, are experiments that document mutations that introduce new "information" to the gene pool, and are beneficial. For example, here is an experiment that shows that 12% of mutations occurring in certain E.coli allowed them to metabolize maltose, "a resource novel to the progenitor".

http://www.pnas.org/content/98/20/11388.abstract

Now, if we humans obtained a mutation that allowed us to metabolize rocks, SURELY that would be considered "new information" in our genetic pool?


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abrown9
Junior Member (Idle past 3239 days)
Posts: 8
From: Thunder Bay, Ontario, Canada
Joined: 08-20-2010


Message 265 of 752 (578759)
09-02-2010 2:20 PM
Reply to: Message 234 by dennis780
09-01-2010 1:34 AM


Did you read the link I sent you or even address the point I was making? I hope you are aware that there are more than one type of experiments that can be done with E. coli (for example I am currently using them in work that deals wholeheartedly with feces).

The experiment showed this:

-There were point mutations.
-12% of these point mutations were beneficial, allowing them to metabolize maltose.
-The ability to use maltose as NRG was novel (ie. NEW!!!) to the progenitor.
-it can be said that genes which code for proteins that help catabolic processes possess information
-since the ability to use maltose was new, it can be called new information

Also what the heck:

"Humans would have been able to eat small rocks in the past (though it wouldn't have provided any nutritional value). The appendix provides a pouch off the main intestinal tract, in which cellulose can be trapped and be subjected to prolonged digestion. Though in humans, the appendix is shrinking, in the past it would have produced cellulose strong enough to eat raw meat, and quite easily digest small rocks."

You simultaneously sidestepped my scenario (where they use rocks for energy) by throwing in this totally irrelevant piece of information (except possibly to show that you will agree that humans have evolved).

Edited by abrown9, : No reason given.


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