FRDB Archives

Freethought & Rationalism Archive

The archives are read only.


Go Back   FRDB Archives > Archives > IIDB ARCHIVE: 200X-2003, PD 2007 > IIDB Philosophical Forums (PRIOR TO JUN-2003)
Welcome, Peter Kirby.
You last visited: Today at 05:55 AM

 
 
Thread Tools Search this Thread
Old 07-08-2003, 02:46 AM   #1
Junior Member
 
Join Date: Jul 2003
Location: Modesto, CA
Posts: 51
Post DNA and information

This is my first post ( though i've been lurking here for a good 8 months ) so i'd like to say hello to everyone...Hello everyone.

I recently had an opportunity to debate with a very bright, albiet misinformed, YEC.

His stance was that abiogenesis/evolution ( which he was informed enough to distinguish between ) were not satisfactory explanations of the origin and diversity of life and thus he took biblical creation as a default position until someone could "show him a better explanation"

Unfortunately his understanding of evolution came mostly from books by Philip Johnson and what he read on AiG so i had a tough time dealing with his many misconceptions ( im definitely not an expert in modern evolutionary theory )

One of our sticking points was his contention that natural selection was incapable of producing "new information"

I've always thought there was something funny about this line of argument but i couldn't nail it down at the time so i pressed on.

Our debate covered just about everything a creationist usually brings up, such as flaws with various dating methods, nearly all mutations being harmful, quick forming fossil and the like.

Eventually i got him to accept that Mutation + Natural selection can lead to new features but he retreated to the old "Microevolution but not Macroevolution" position.

We continued to debate a bit via e-mail and one of his responses focused heavily on the "no new information" slant.

I put a good deal of effort into my reply to him so i thought i'd post it here to get some criticism and perhaps polish it up a bit.

So here it is, please rip it up for me

Quote:
After quite a bit of pondering i think i've finally nailed down what struck me as incorrect in the "evolution doesn't lead to new information" line of argument.

As i suggested when we met at starbucks, i believe the problem is one of definitions and also of misapplied analogy.

Before i begin, i'd like to make a point which i think is of utmost importance.

Words are only meaningful as we define them.

By this i mean that, a given word used in a given context cannot be assumed to mean the same thing in another context.

Let us say, for instance that i am looking over a car, in this case a 1972 volkswagen beetle, and noticing that it has a white paint job i remark, "This car is light"

What i mean by light in this context is, to quote merriam-webster.com, is "2 a : not dark, intense, or swarthy in color or coloring : PALE "

Now, say im investigating another beetle, this time a black one, and i lift the front end by its bumper. I might once again remark "This car is light"

However in this case im not saying, "2 a : not dark, intense, or swarthy in color or coloring : PALE". I am in fact saying "1 a : having little weight : not heavy"

In both cases i am using the same word, "light", but the word carries drastically different meanings.

The point here is that we must realize that the fact that two situations use the same terminology does not necessarily imply that said terminology carries the same meanings.

Another important point is that relationships between the ideas symbolized by a given word do not carry over when the word's meaning is changed by its context.

If you and i were discussing the first car and i mentioned that it was light you would agree with me because, being white, it is clearly not dark.

But, if during the course of our discussion of the second car i once again commented that it was light (refering to its weight this time), it would make no sense for you object that this cannot be true because the car is black. As the definition of "light" is different in this context its former conceptual relationships are void.

so clearly it behoves us to be very precise about defining the terms we use.

Now, on to the problem at hand.

The word "information" is used in two contexts which are relavent to our discussion.

The first context i'll address is human language. In our language information is, in my estimation, knowledge expressed via combinations of letters to form words, and combinations of words to form sentences and so on.

Our language doesn't just use any combination of letters to form words. We, as intelligent entities come together and agree on meanings for specific combinations.

Therefor the word "turtle" for instance is agreed upon to represent a group of aquatic or semi-aquatic shelled reptiles.

"rtletu" on the other hand is meaningless.

However, in the absence of we, the intelligent entities which dictate the meaning of given combinations of letters, "rtletu" carries just as much information as "turtle". Without us to determine the information represented by these combinations they both carry no information at all.

Nothing about the world turtle mandated that it be used to represent aquatic or semi-aquatic shelled reptiles. The descision that it would carry that information is entirely arbitrary.

If i wish to i can announce that the word turtle is defined to mean "Computer Science" and write an essay on the "latest advances in the field of turtle relating to neuro-network computing" and it would be entirely valid. All that is important is that i let the reader know before hand exactly what "turtle" is going to mean in the context of my essay.

The important point here is that the information encoded by a given sequence of letters is arbitrarily defined by we who make use of a language.

Now, for the case of information encoded in the genome of organisms. Information, as you applied it in this context, seems to mean the features of the organism which are encoded from a given sequence of base pairs in its DNA.

As i understand it (you must forgive my very simplified knowledge of these processes as i am a humble music major and have never taken more than introductory biology and chemistry) a given sequence of base pairs is encoded into an amino acid to build a protein which in turn regulates certain factors in the organism such as tissue growth and what not.

Now comes the important point of divergence of our two contexts. The "information" contained in a given sequence of base pairs is determined by the rules or chemistry. It is, unlike our language, in no way arbitrary.

I cannot take a given sequence of base pairs, announce that it now represents an entirely different amino acid, and expect it's expression in an organism to change obligingly. Regardless of what we who observe the process may think of it, the expression of a given sequence of base pairs is entirely pre-determined by the unchanging ( we assume, they certainly haven't changed recently ) laws of chemistry.

For example, in the case of a certain species of Flavobacterium (Flavobacterium sp.K172) suffered a frame shift mutation in a series of base pairs that encoded an enzyme. This sort of mutation results when a base pair or group of base pairs is inserted or deleted and is not a multiple of three. http://www.nmsr.org/nylon.htm has a nice explanation for the way this effects protein construction ( just dont get too caught up in their language based analogies )

The original sequence of the affected area was:

...C-G-A-G-A-A-C-G-C-A-C-G-T-T-C-C-A-C-C-G-G-C-C-A-G...

This became:

...C-G-A-[T]-G-A-A-C-G-C-A-C-G-T-T-C-C-A-C-C-G-G-C-C-A-G...

As you can see, a single base was inserted. This sort of mutation is almost invariably fatal as it radically alters the protein which is created. The key, however, is that although the order of the series is changed and it likely will no longer encode for something useful, it must encode something.

There is no such thing as a gibberish series of base pairs, they all represent code for a protein regardless of whether the encoded protein is usefull or not.

In the case of this bacterium, as luck would have it, this single insertion ( Note, not a deletion. The point you made before about new features always representing losses of base pairs, though it was not valid in the sense you thought it, is satisfied by this case. ) happened to disrupt the series in such a manner that it now encoded for an enzyme that allowed the bacteria to metabolize nylon by-products.

Thus, the bacteria has gained a new and novel feature (guarenteed to be completely new since nylon didn't exist before 1935) from a random insertion of a base pair. All because the laws of chemistry mandate that every series of base pairs, no matter how you change it from a "working" series, must encode for something.

So now, perhaps, you see why i said that thinking about novel features gained through mutation and subsequent natural selection as "new information" is a bad idea.

"information" as we are used to using it, is based on arbitrary assignments by intelligent entities. For our analogy inclined minds it becomes difficult to concieve of "new information" being created by an unintelligent process.

Thus my suggestion that we view such novel features as mutation "stumbling" upon another of the myriad of chemically predetermined combinations which happen to convey some benefit in a given environment.

I suppose the morals of this story are that we always must be sure to give clear definitions and we must be wary of relying on analogies for our understanding; lest we later discover that the situations were not truly analogous!
Im hoping i didn't botch things too bad.

I think i did alright as i've yet to hear a peep out of him since i sent it to him
BrianTerrel is offline  
Old 07-08-2003, 03:50 AM   #2
Senior Member
 
Join Date: Feb 2003
Location: San Diego, California
Posts: 719
Default

I think it's a very well phrased and well thought out response. Nice job.
Lobstrosity is offline  
Old 07-08-2003, 04:38 AM   #3
Senior Member
 
Join Date: Jan 2002
Location: California
Posts: 646
Default

Hi,

You might find this thread useful:

The Origin of "Information" via natural causes
http://www.antievolution.org/cgi-bin...act=ST;f=9;t=6
Nic Tamzek is offline  
Old 07-08-2003, 06:41 AM   #4
Veteran Member
 
Join Date: Jun 2000
Posts: 1,302
Default

It is hard to find and heavy on the math -

Kimura, M. 1961. Natural selection as the process of accumulating genetic information in adaptive evolution.

Of course, you can always ask the guy what he means by "information," how it applies to biological systems, and whether or not he feels that things like gene duplications, insertions, etc. affect the amount or "newness" of the information.

There are many examples of what creationist information hawks generally claim are not increases in information or "new" information yet alter phenotpye and/or produce benfits.
pangloss is offline  
Old 07-08-2003, 07:12 AM   #5
Veteran Member
 
Join Date: Nov 2001
Location: NCSU
Posts: 5,853
Default Here is my stock Information post.

INFORMATION
Individuals don't evolve. Populations do. So in linking information theory to evolution, one must consider the information in the population, which creationists do not do. Biologically, information can refer to different things. Pseudogenes, contain information about evolutionary history but not information that can be selected upon. In the context of this discussion, it would be best right now to consider the genetic information underlying traits, with an interest in adaptable traits. It is difficult to determine a way to measure the amount of this information, but one possibility is the size of the proteome. This is the number of unique proteins produced in the population and includes all loci and alleles. Whenever a mutation produces a novel allele, it adds information to the population. In other words, there is a new trait for selection to act upon. Here are two examples of the effects of information in a population.

Jeff knows something about Gina: "Gina is neat." Thus he has information about Gina. Before he leaves town, Jeff replicates this information by telling it to two people, Nick and Randy. Because neither of them pays attention, they don’t replicate the information exactly. Nick thinks "Gina is sweat," and Randy thinks "Gina is near." We can measure the about of information about Gina by the number of non-redundant attributes people ascribe to her. Here, the amount of information about Gina has doubled: from "neat" to "sweat and near." Clearly when we remember that it is the population that’s important to evolution, it is obvious how mutations can add information for selection to act upon.

Take this example retrieved from LocusLink [1], the only difference occurs in the 7th codon (6th amino acid because the first one, 'm,' gets cut off). The letters refer to amino acids [2].
Code:
Human Beta-hemoglobin (HBB)
  1 mvhltpeeks avtalwgkvn vdevggealg rllvvypwtq rffesfgdls tpdavmgnpk
 61 vkahgkkvlg afsdglahld nlkgtfatls elhcdklhvd penfrllgnv lvcvlahhfg
121 keftppvqaa yqkvvagvan alahkyh


HBB-S
  1 mvhltpveks avtalwgkvn vdevggealg rllvvypwtq rffesfgdls tpdavmgnpk
 61 vkahgkkvlg afsdglahld nlkgtfatls elhcdklhvd penfrllgnv lvcvlahhfg
121 keftppvqaa yqkvvagvan alahkyh


HBB-C
  1 mvhltpkeks avtalwgkvn vdevggealg rllvvypwtq rffesfgdls tpdavmgnpk
 61 vkahgkkvlg afsdglahld nlkgtfatls elhcdklhvd penfrllgnv lvcvlahhfg
121 keftppvqaa yqkvvagvan alahkyh
Each allele does not encode the exact same information since each one produces a distinctly different product. A single point mutation has enough effect on the information contained in the genome that it can determine whether an individual dies from malaria or not. In the presence of malaria, HBB-S is maintained because of heterozygote advantage. However, HBB-C also offers resistance to malaria, but the most fit genotype is the homozygote.[3] It is expected to become the most common allele in parts of Africa if the environment stays the same. These mutations have clearly added new information to the population. Selection then acts on this new information, changing the make up of the population. Thus, evolution happens.

It is important to realize that evolution occurs even if information is lost. It also occurs when information is gained or without any change in the amount of information at all. Thus no-new-information arguments do not actually address evolutionary theory. By focusing on individuals and not populations, no-new-information claims never even get close to disproving evolution. In fact, the actual claim, when applied to biology, is that the information capacity of an individual's genome cannot increase. However, this claim is false because there are known types of mutations that can increase the length of the genome and thus its capacity to hold information. Ernst Mayr discusses this origin of new genes in his latest book:

Quote:
Bacteria and even the oldest eukaryotes (protists) have a rather small genome. . . . This raises the question: By what process is a new gene produced? This occurs, most frequently, by the doubling of an existing gene and its insertion in the chromosome in tandem next to the parental gene. In due time the new gene may adopt a new function and the ancestral gene with its traditional function will then be referred to as the orthologous gene. It is through orthologous genes that the phylogeny of genes is traced. The derived gene, coexisting with the ancestral gene, is called paralogous. Evolutionary diversification is, to a large extent, effected by the production of paralogous genes. The doubling sometimes affects not merely a single gene, but a whole chromosome set or even an entire genome.[4]
1. http://www.ncbi.nlm.nih.gov/LocusLink/
2. http://www.chem.qmul.ac.uk/iupac/AminoAcid/AA1n2.html
3. Modiano D. et al. (2001) Haemoglobin C protects against clinical plasmodium falciparum malaria. Nature: 414 pp 305-308
4. Mayr E. (2001) What Evolution Is. Basic Books.
RufusAtticus is offline  
Old 07-08-2003, 07:31 AM   #6
Veteran Member
 
Join Date: Jun 2001
Location: Denver, CO, USA
Posts: 9,747
Default

Here's another good resource:

Information Theory and Creationism

As far as I can tell, there have only been three anti-evolutionists who have tried actually to formalize their "no new information" claim -- the rest are just making assertions. None of these three withstands scrutiny. Gitt's is a matter of circular reasoning, and Spetner's is inconsistent. Dembski's is both circular and inconsistent.

theyeti
theyeti is offline  
Old 07-08-2003, 07:33 AM   #7
Veteran Member
 
Join Date: Jan 2001
Location: Median strip of DC beltway
Posts: 1,888
Default

I usually just ask "Shannon information or Kolmogorov information?". The usual response is "just normal information", at which point anything said usually changes the topic.
NialScorva is offline  
 

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Forum Jump


All times are GMT -8. The time now is 06:29 PM.

Top

This custom BB emulates vBulletin® Version 3.8.2
Copyright ©2000 - 2015, Jelsoft Enterprises Ltd.