Evolution "just a theory"?

[gluadys]

True, and flawed theories are almost always falsified. Evolution has not been falsified in its 150 year history despite many, many attempts. This speaks volumes for how accurate it is likely to be.

For a theory to be falsified it has to be falsifiable. Only the parts of evolutionary biology that everyone accepts (natural selection determining moth color based upon available camoflage etc.) are empirically verifiable. The proposition that the mechanics of the human eye arose from random chance is untestable, just as one cannot disprove the existence of God or the Easter Bunny.

But according to the theory of evolution, the mechanics of the human eye did NOT arise from random chance.

This is one of the major mis-understandings of evolution by those who have not studied the theory.

Mutations are random. Evolution (adaptation) is not.

 

[Aeschylus]

True, and flawed theories are almost always falsified. Evolution has not been falsified in its 150 year history despite many, many attempts. This speaks volumes for how accurate it is likely to be.

For a theory to be falsified it has to be falsifiable. Only the parts of evolutionary biology that everyone accepts (natural selection determining moth color based upon available camoflage etc.) are empirically verifiable. The proposition that the mechanics of the human eye arose from random chance is untestable, just as one cannot disprove the existence of God or the Easter Bunny.

Incorrect. A theory must make predict certain observations to be falisifable, evoltuionary theory does that, secondly it does not say the human eye arose enirely by chance it says it arose out of the process of natural selction which observation agrees with.

 

[gluadys]

Okay. So my understanding of evolution is limited. How about you explain to me the way that life evolved in the first place and then the way people evolved from those first assumed primitive life forms. I take it this is known since evolution is a scientific certainty.

Yes, since evolution has been observed, it is a scientific certainty. The theory about how evolution happens is not a scientific certainty, although it is very, very probable.

We don't explain how life itself evolved, since by definition life has to exist before it can evolve. The science which looks at possible pathways for the origin of life is called abiogenesis. There are several competing theories and ongoing research in this field.

Probably the best way to understand human evolution is not to try to begin at the beginning with simple cellular forms of life, but to begin with humans and look at how they evolved from their closest ancestors such as Homo erectus and work backward from there. This will eventually take you back to the common ancestor of humans and chimps, and then to the common ancestor of all the great apes, and so on. By the time you get back to the evolution of multi-cellular animal life from unicellular life, you'll be a pro and the problem that seems insurmountable now will dissolve.

I am looking for an explanation for the way new genetic information evolved. I understand that a horse has about four times the amount of DNA as a simple cell amoeba. I'm looking for an explanation for the way the genetic information of the eyes, ears, lungs, etc, came into existance.

First you need to be clear on what you mean by "new" genetic information. All genetic information is based on the sequence of four nucleotides in DNA and RNA, just as all information in the English language is based on 26 letters of the alphabet. So right off the bat, you need to understand that when we speak of new information, we are not speaking of new nucleotide bases any more than we are speaking of adding new letters to the alphabet.

Same goes for codons. Codons are the three-base sequences of DNA or RNA that code for amino acids. There are 64 codons altogether. Three of them are a "stop" code signalling the end of a set of amino acid sequences. The others code for one of 20 amino acids. Since there are 3 times as many codons as amino acids used to build proteins, there is a built-in redundancy with some amino acids having more than one source code.

But when we speak of new genetic information, we are not speaking of adding new codons and therefore we are not speaking of adding new amino acids.

ok?

From 20 amino acids however, we can get hundreds and hundreds of different proteins, just as 26 letters in the alphabet can give us millions of different words, and those words in turn can give us zillions of different sentences and paragraphs and books without end. Furthermore, by recombining letters and/or words we can make new words that never existed in the language before.

Same goes for amino-acid generated proteins. Change a nucleotide (letter) or a codon (syllable) in some way, and you change the amino acid that is coded for. Change the amino acid, and you change the protein. Even without adding more DNA, such re-arrangements can give you completely novel proteins, just as re-arrangements of letters can give you completely novel words. Or re-arrangements of words can give you completely novel sentences.

And since one of the possible changes is duplication of DNA, you can add more DNA as well. Everything from adding a single nucleotide base, to doubling the whole genome (something that happens now and again in plants. It's called "polyploidy")

Does that help solve some riddles about how to get new genetic information?

Natural selection can change gene frequencies, and sometimes a complete loss of genetic information. We need a gain in DNA, and that gain has to somehow assemble itself to produce the things mentioned above. Tell us all about the evidence that you have that demostrates this. Nature should about with examples of such things if evolution is true, and proven.

What do you mean by a "complete" loss of genetic information. To me that implies a complete loss of DNA. As long as DNA exists, genetic information exists.

No, in particular instances, we do not need a gain in DNA. Loss of DNA is also a mutation, a change in genetic information, and it can also result in a new variation.

In general we observe an increase in DNA as we move from observing simple unicellular life, to observing complex multi-cellular life. At the same time there is no straight-line correlation between the number of chromosomes and genes a species has and its overall complexity. For example, because of the relative frequency of polyploidy in plants, some of them have chromosome numbers well above those of other plants and animals which are equally or more complex.

 

[BWV 1080]

But according to the theory of evolution, the mechanics of the human eye did NOT arise from random chance.

This is one of the major mis-understandings of evolution by those who have not studied the theory.

Mutations are random. Evolution (adaptation) is not.

What are you saying? Either evolution is a random process or there is a creator behind it (such as with theistic evolution). If the human eye is not the end result of millions of random mutations guided by natural selection then how was it created / designed?

 

[BWV 1080]

Incorrect. A theory must make predict certain observations to be falisifable, evoltuionary theory does that, secondly it does not say the human eye arose enirely by chance it says it arose out of the process of natural selction which observation agrees with.

I agree with Karl Popper that empirical falsifiability sets the boundaries of science. The observations that are falsifiable no one disputes (Moth color etc.). Other observations of evolutionary theory are mostly speculative.

Evolution does fit the defintion of a scientific theory in many respects, however its explanations about the human eye, to continue with the same example, are unverifiable.

Evolution presupposes random chance unless one believes in some unseen force or guiding hand behind it. What do you think guides the process of natural selection? Random chance , such as a change in climate, asteroid strike obliterating the dinosaurs, etc.

 

[Aeschylus]

I agree with Karl Popper that empirical falsifiability sets the boundaries of science. The observations that are falsifiable no one disputes (Moth color etc.). Other observations of evolutionary theory are mostly speculative.

Evolution does fit the defintion of a scientific theory in many respects, however its explanations about the human eye, to continue with the same example, are unverifiable.

Evolution on a geological timescale is falsifable as it makes specifc predictions about homolgy, the fossil record and gentics all of which have proven to be correct.

Evolution presupposes random chance unless one believes in some unseen force or guiding hand behind it. What do you think guides the process of natural selection? Random chance , such as a change in climate, asteroid strike obliterating the dinosaurs, etc.

Evolution does not need random chance infact when it was first proposed many believd thta ther was no such thing as true randomness. It is about trends in populations.

 

[BWV 1080]

Evolution on a geological timescale is falsifable as it makes specifc predictions about homolgy, the fossil record and gentics all of which have proven to be correct.

No it has not. Macroevolution would presuppose the following: (from an excellent article at http://acs.ucsd.edu/~idea/falsify.htm)

[font=Verdana, Arial, Helvetica, sans-serif]Predictions of Descent[/font][font=Verdana, Arial, Helvetica, sans-serif]1. High information content machine-like irreducibly complex structures will NOT be found.9, 27, 31, 32, 33
2. Forms will appear in the fossil record as a gradual progression with transitional series.34
3. Genes and functional parts will reflect those inherited through ancestry, and are only shared by related organisms.

4. The genetic code will contain much discarded genetic baggage code or functionless "junk DNA".[/font]
These are not evident in nature, rather we have:

[font=Verdana, Arial, Helvetica, sans-serif]Predictions of Intelligent Design[/font][font=Verdana, Arial, Helvetica, sans-serif](1) High information content machine-like irreducibly complex structures will be found.9
(2) Forms will be found in the fossil record that appear suddenly and without any precursors.10
(3) Genes and functional parts will be re-used in different unrelated organisms.29
(4) The genetic code will NOT contain much discarded genetic baggage code or functionless "junk DNA".30[/font]

Now, just like astrology or young-earth creationism, evolutionary theory can be conformed to fit any evidence offerred.

Evolution does not need random chance infact when it was first proposed many believd thta ther was no such thing as true randomness. It is about trends in populations.

Random chance is somewhat of a philisophical construct. Either evolution is random or there was some inconceivably complex deterministic chain of events that began with the big bang. If God exists, then the outcome could reflect his sovereign plan, if not, whether it is truly "random" or not makes no difference because life is too complex and chaotic to predict and there is no creator or guiding hand in the process.

There are no predictable "trends in populations" beyond the most rudementary and naive examples (it did not rain so plants died causing starvation up the food chain, etc.). Nature is too chaotic too predict secondary and tertiary consequences of "trends in populations". Just because I can see trends when I plot my bankroll over time at a blackjack table does not mean that they have any predictive value.

 

[gluadys]

What are you saying? Either evolution is a random process or there is a creator behind it (such as with theistic evolution). If the human eye is not the end result of millions of random mutations guided by natural selection then how was it created / designed?

You see, this time you referred to natural selection. In your earlier post you did not. It is always important to remember that natural selection is at least as important, maybe more important, than mutations.

Millions of mutations have no effect on evolution at all. They occur in non-coding parts of the genome, or they have a neutral effect like slightly reshaping an eyebrow (though you can never tell what is really neutral).

But natural selection is what gives mutations power to re-shape a species---or prevents it. When a mutation is harmful to an individual the individual has less opportunity to reproduce, and its offspring may be weak, non-viable or sterile, so that mutation does not get a foothold in the species, and the species remains unharmed. But when a mutation provides an individual with an advantage, its own opportunity of reproducing is enhanced, and so are the opportunties of its offspring, producing a multiplier effect that quickly spreads the beneficial change to the whole species.

It is natural selection which assures that changes which benefit a species, and only changes which benefit a species, get spread through the species, so the changes in a species are always in the direction of better adaptation. So the end result of natural selection is design. Yet the process is entirely natural needing no prompting.

For an excellent discussion of the evolution of the eye, see Climbing Mount Improbable by Richard Dawkins.

Now while science can give a full account of evolution without referring to anything but natural causes, this does not imply, for a TE, that God is not involved in evolution also. But as to how God is involved, that is a question for another post. I'm too tired to write more tonight.

 

[BWV 1080]

You see, this time you referred to natural selection. In your earlier post you did not. It is always important to remember that natural selection is at least as important, maybe more important, than mutations.

Millions of mutations have no effect on evolution at all. They occur in non-coding parts of the genome, or they have a neutral effect like slightly reshaping an eyebrow (though you can never tell what is really neutral).

But natural selection is what gives mutations power to re-shape a species---or prevents it. When a mutation is harmful to an individual the individual has less opportunity to reproduce, and its offspring may be weak, non-viable or sterile, so that mutation does not get a foothold in the species, and the species remains unharmed. But when a mutation provides an individual with an advantage, its own opportunity of reproducing is enhanced, and so are the opportunties of its offspring, producing a multiplier effect that quickly spreads the beneficial change to the whole species..

Yes, this is a textbook definition of natural selection

It is natural selection which assures that changes which benefit a species, and only changes which benefit a species, get spread through the species, so the changes in a species are always in the direction of better adaptation. So the end result of natural selection is design. Yet the process is entirely natural needing no prompting.

For an excellent discussion of the evolution of the eye, see Climbing Mount Improbable by Richard Dawkins.

"It is demonstrable," said he, "that things cannot be otherwise than as they are; for as all things have been created for some end, they must necessarily be created for the best end. Observe, for instance, the nose is formed for spectacles, therefore we wear spectacles. The legs are visibly designed for stockings, accordingly we wear stockings. ... they, who assert that everything is right, do not express themselves correctly; they should say that everything is best." - Pangloss


My skepticism centers around whether natural selection is an adequate mechanism for the what it is claimed to accomplish. Behe and others IMO make some very good points about how mechanisms exist in nature that are very difficult to extrapolate millions on tiny, random mutational improvements into.

 

[gluadys]

Yes, this is a textbook definition of natural selection


"It is demonstrable," said he, "that things cannot be otherwise than as they are; for as all things have been created for some end, they must necessarily be created for the best end. Observe, for instance, the nose is formed for spectacles, therefore we wear spectacles. The legs are visibly designed for stockings, accordingly we wear stockings. ... they, who assert that everything is right, do not express themselves correctly; they should say that everything is best." - Pangloss

Ah, Voltaire sure knew how to write! Candide was required reading in our French literature class. Of course, Pangloss's teleology is repudiated by evolution. Natural selection has no design goals, only design results.

My skepticism centers around whether natural selection is an adequate mechanism for the what it is claimed to accomplish. Behe and others IMO make some very good points about how mechanisms exist in nature that are very difficult to extrapolate millions on tiny, random mutational improvements into.

Be skeptical by all means, but not so skeptical that you throw away good evidence of natural selection working. Behe, at least, limits his criticisms to the level of biochemistry. I don't know enough about biochemistry to say if he is right or wrong, but I have seen some on-line papers that challenge his points. Have you checked them out? You can find a collection of them at talkdesign.

In any case, Behe is also on record as fully supporting evolution of all organisms from a common ancestor by Darwinian mechanisms. So his skepticism about certain molecular processes does not extend to species change and speciation via mutation and natural selection. Any reason you feel the need to be more skeptical than he is?

 

[BWV 1080]

In any case, Behe is also on record as fully supporting evolution of all organisms from a common ancestor by Darwinian mechanisms. So his skepticism about certain molecular processes does not extend to species change and speciation via mutation and natural selection. Any reason you feel the need to be more skeptical than he is?

I don't think I am. While he does support a common ancestor, as the article below illustrates he is skeptical of natural selections ability on its own to account for the full diversity of life. He also states that the theory of evolution is practically untestable (which was my original point in the thread).



http://www.arn.org/docs/behe/mb_dm11496.htm
...
I want to be explicit about what I am, and am not, questioning. The word "evolution" carries many associations. Usually it means common descent -- the idea that all organisms living and dead are related by common ancestry. I have no quarrel with the idea of common descent, and continue to think it explains similarities among species. By itself, however, common descent doesn't explain the vast differences among species.

That's where Darwin's mechanism comes in. "Evolution" also sometimes implies that random mutation and natural selection powered the changes in life. The idea is that just by chance an animal was born that was slightly faster or stronger than its siblings. Its descendants inherited the change and eventually won the contest of survival over the descendants of other members of the species. Over time, repetition of the process resulted in great changes -- and, indeed, wholly different animals.

That's the theory. A practical difficulty, however, is that one can't test the theory from fossils. To really test the theory, one has to observe contemporary change in the wild, in the laboratory or at least reconstruct a detailed pathway that might have led to a certain adaptation.

Darwinian theory successfully accounts for a variety of modern changes. Scientists have shown that the average beak size of Galapagos finches changed in response to altered weather patterns. Likewise, the ratio of dark- to light-colored moths in England shifted when pollution made light-colored moths more visible to predators. Mutant bacteria survive when they become resistant to antibiotics. These are all clear examples of natural selection in action. But these examples involve only one or a few mutations, and the mutant organism is not much different from its ancestor. Yet to account for all of life, a series of mutations would have to produce very different types of creatures. That has not yet been demonstrated.

Darwin's theory encounters its greatest difficulties when it comes to explaining the development of the cell. Many cellular systems are what I term "irreducibly complex." That means the system needs several components before it can work properly. An everyday example of irreducible complexity is a mousetrap, built of several pieces (platform, hammer, spring and so on). Such a system probably cannot be put together in a Darwinian manner, gradually improving its function. You can't catch a mouse with just the platform and then catch a few more by adding the spring. All the pieces have to be in place before you catch any mice.

An example of an irreducibly complex cellular system is the bacterial flagellum: a rotary propeller, powered by a flow of acid, that bacteria use to swim. The flagellum requires a number of parts before it works -- a rotor, stator and motor. Furthermore, genetic studies have shown that about 40 different kinds of proteins are needed to produce a working flagellum.

The intracellular transport system is also quite complex. Plant and animal cells are divided into many discrete compartments; supplies, including enzymes and proteins, have to be shipped between these compartments. Some supplies are packaged into molecular trucks, and each truck has a key that will fit only the lock of its particular cellular destination. Other proteins act as loading docks, opening the truck and letting the contents into the destination compartment.

Many other examples could be cited. The bottom line is that the cell -- the very basis of life -- is staggeringly complex. But doesn't science already have answers, or partial answers, for how these systems originated? No. As James Shapiro, a biochemist at the University of Chicago, wrote, "There are no detailed Darwinian accounts for the evolution of any fundamental biochemical or cellular system, only a variety of wishful speculations."

A few scientists have suggested non-Darwinian theories to account for the cell, but I don't find them persuasive. Instead, I think that the complex systems were designed -- purposely arranged by an intelligent agent.

Whenever we see interactive systems (such as a mousetrap) in the everyday world, we assume that they are the products of intelligent activity. We should extend the reasoning to cellular systems. We know of no other mechanism, including Darwin's, which produces such complexity. Only intelligence does.

Of course, I could be proved wrong. If someone demonstrated that, say, a type of bacteria without a flagellum could gradually produce such a system, or produce any new, comparably complex structure, my idea would be neatly disproved. But I don't expect that to happen.

Intelligent design may mean that the ultimate explanation for life is beyond scientific explanation. That assessment is premature. But even if it is true, I would not be troubled. I don't want the best scientific explanation for the origins of life; I want the correct explanation.

 

[Karl - Liberal Backslider]

Behe makes two errors, as Ken Miller has frequently pointed out:

1) Possible evolutionary pathways have been postulated for many of the IC systems he raises as problems, and others are being found.

2) His mousetrap analogy assumes that the purpose of a mousetrap has always been to catch mice.

 

[Micaiah]

First you need to be clear on what you mean by "new" genetic information. All genetic information is based on the sequence of four nucleotides in DNA and RNA, just as all information in the English language is based on 26 letters of the alphabet. So right off the bat, you need to understand that when we speak of new information, we are not speaking of new nucleotide bases any more than we are speaking of adding new letters to the alphabet.

Same goes for codons. Codons are the three-base sequences of DNA or RNA that code for amino acids. There are 64 codons altogether. Three of them are a "stop" code signalling the end of a set of amino acid sequences. The others code for one of 20 amino acids. Since there are 3 times as many codons as amino acids used to build proteins, there is a built-in redundancy with some amino acids having more than one source code.

But when we speak of new genetic information, we are not speaking of adding new codons and therefore we are not speaking of adding new amino acids.

ok?

From 20 amino acids however, we can get hundreds and hundreds of different proteins, just as 26 letters in the alphabet can give us millions of different words, and those words in turn can give us zillions of different sentences and paragraphs and books without end. Furthermore, by recombining letters and/or words we can make new words that never existed in the language before.

Same goes for amino-acid generated proteins. Change a nucleotide (letter) or a codon (syllable) in some way, and you change the amino acid that is coded for. Change the amino acid, and you change the protein. Even without adding more DNA, such re-arrangements can give you completely novel proteins, just as re-arrangements of letters can give you completely novel words. Or re-arrangements of words can give you completely novel sentences.

And since one of the possible changes is duplication of DNA, you can add more DNA as well. Everything from adding a single nucleotide base, to doubling the whole genome (something that happens now and again in plants. It's called "polyploidy")

Does that help solve some riddles about how to get new genetic information?

No, it doesn't. Give some serious thought to the way DNA for new features is supposed to be added.

 

[Karl - Liberal Backslider]

The genetic evidence is that gene duplications result in two genes for the same protein. These can then mutate seperately, resulting in the two genes coding for different proteins. This is one way that the DNA for new functions gets into the genome.

 

[BWV 1080]

Behe makes two errors, as Ken Miller has frequently pointed out:

1) Possible evolutionary pathways have been postulated for many of the IC systems he raises as problems, and others are being found.



2) His mousetrap analogy assumes that the purpose of a mousetrap has always been to catch mice.

Well it is by no means settled and Behe has rebuttals for Miller:

http://www.arn.org/docs/behe/mb_trueacidtest.htm



How a layman (like myself) whose background consists of a single undergraduate biology course can evaluate the relative merits of this debate is beyond me. It seems to me very likely that adequate scientific proof will never be found to resolve these questions in the same manner that past scientific controversies have been settled. Furthermore, there is too much philosophic baggage to really have an objective discussion, the way one might do on a more trivial topic. The biggest factor is that the Theory of Evolution has given atheists a creation myth that can be used to explain every aspect of human existence. I know a distinction needs to be made between scientific and philosophic “evolutionism”. However, that the most prominent scientific proponents of evolution are also the most hardcore proponents of philosophical “evolutionism” lends support to the view that Dawkins & Co. have just as much irrational emotional attachment to their beliefs as the stereotypical literal 7-day creationist.

 

[Micaiah]

The genetic evidence is that gene duplications result in two genes for the same protein. These can then mutate seperately, resulting in the two genes coding for different proteins. This is one way that the DNA for new functions gets into the genome.

References and examples please. Is this the official line on how these are supposed to occur?

 

[Karl - Liberal Backslider]

Of course!

http://biocrs.biomed.brown.edu/Darwin/DI/clot/Clotting.html
http://www.eurekalert.org/pub_releases/2004-08/bc-gda081604.php
http://biology.kenyon.edu/courses/biol114/Chap09/Chap09A.html - bottom section, on opsins.

Project on the topic here at the University of Ghent: http://bioinformatics.psb.ugent.be/psb/current_projects_gendup.htm

Yes, this is pretty well established stuff.

 

[Gold Dragon]

MedicineNet.com : Gene Duplications
Wikipedia : Gene Duplication
Yeast Gene Duplications

 

[gluadys]

No, it doesn't. Give some serious thought to the way DNA for new features is supposed to be added.

As far as I know (unless God is pulling some strings behind the scenes) DNA is not added in order to get new features. But when DNA is added sometimes a new feature or a modified feature is the result.

Of course this can also be the result of DNA being subtracted, or transposed or substituted as well.

There is nothing all that special about duplication except that one of the results is that there is more volume of DNA and hence more features can be coded for, after further mutations.

So what do you see as the problem?

 

[Vance]

The whole "no new information" theory is just the latest "fall-back" position YEC psuedo-scientists have resorted to because their earlier propositions (no evidence of speciation, etc) have been proven SO wrong even they had to finally admit it. This new attempt to disprove macro-evolution has the benefit of being simple to state as a YEC proposition, but subtle and complex enough that the explanations from scientists as to why it is simply not true has to be "over the head" of the average YEC, so they just write it off as evolutionist double-talk.

But you can check out my thread entitled "Information about Information Theory" for an explanation as to why YEC's have yet another faulty proposition and should be looking around for another fall-back.