So I got a comment today on one of my old evolution posts that annoyed me at first and then made me sad. The author throws out a few creationist “arguments” without actually calling them arguments, and so I felt I needed to respond. His comment follows (indented and in gray), with my response in-line (and not indented).
Your first few paragraphs state:
“Actually evolution is a matter of scientific fact”
“Science does not prove anything”
You seem confused
I’m never confused!
That was a lie, but in this case I certainly wasn’t confused. You, however, are clearly confused on what I meant by “proof”. Which was a big part of the point of what I said. Proof doesn’t exist. Only evidence does. By “scientific fact” I of course mean something that is backed by enough evidence to be considered true. But it isn’t “proved”. It can’t be. That was my point.
Keeping it simple:
DNA can’t exist (in a living state) without protein.
Now, by “simple” you must mean “stupid”:
DNA can (and does) exist without proteins. Your parenthetical expression “in a living state” doesn’t mean anything. DNA is not alive. If you meant that it can’t exist in a living thing (a cell) without protein, that isn’t true either, but more accurate.
Protein cant exist (in a living state) without DNA.
Protein can (and does) exist without DNA. I assume that you meant that it can’t be created without DNA, which is much more accurate. But still wrong. It actually needs RNA to be created. But the RNA does indeed come from the DNA (mediated by proteins). Bear in mind RNA-genome viruses; no DNA necessary (though you could argue that their reliance on host proteins, which do require DNA, negates that negation).
So I assume your problem is with the circularity of the “Central Dogma” of biology: DNA->RNA->Proteins, which then mediate that very process. This problem only exists under your mistaken understanding that the whole shebang evolved at once. Which doesn’t make any sense and isn’t part of evolutionary theory.
Odds have been calculated that to evolve ONE single protein of only 200 enzymes (in the correct order)
the odds are greater than all the atoms in the universe.
This same confusion leads to your next completely pointless point. This is only a fair critique if you, again, assume that the entire protein was created in one go. Or spontaneously created by an outside force. The odds against that are, indeed, insurmountable. That’s the whole point of evolution; you take it slow, so that each step is probable enough to occur.
For anyone unfamiliar with this particular creationist “argument”, it is an excellent demonstration of that fact that you can interpret statistics to mean anything you want when you don’t understand their context. The idea is this. Proteins are made up of amino acids, of which there are 20 possibilities in people and nearly every other organism (though some critters have some extras, mostly through post-transcriptional modifications (meaning changes to the amino acids after the protein is already made)). So, if the process of assembling amino acids was completely random then, for example, a 100 aa (amino acid) protein could be made in 20 to the 100th power ways. This number is so large that it doesn’t even make sense.
So the “argument” goes something like this: “There are more possible amino acid combinations for even a short protein than there are atoms in the universe. That means that the likelihood of a protein with a specific sequence of 100 amino acids is so unlikely to occur that we can safely call the probability zero. Therefore god(s) did it.”
Anyone familiar with statistics at all would immediately notice that this number only makes sense if the process of creating a protein is random. And it isn’t. So this “argument” is completely invalid because it has nothing to do with evolution. It’s like saying “mountains are friggin’ GIGANTIC, so there is no way that evolution could have happened.” See? That doesn’t make any sense! This creationist tactic takes advantage of the fact that most people don’t understand statistics or evolution. And when I say “takes advantage” it appears that I am giving credit to creationists for being clever. The sad fact is that creationists actually believe this “argument” and that’s why they present it. They are generally incapable of understanding why this has nothing to do with evolution. But anyway, continuing along.
Then (after it surmounts those odds)it has to fold itself into a complex exact 3D shape.
After managing this if it doesnt have hundreds more proteins with it and some working DNA it’ll die.
As for the folding problem, a protein’s sequence and its folding pattern are basically the same thing. So you’re just stating the same problem (which isn’t actually a problem) twice. A protein’s sequence defines its 3D structure, because of the hydrophobic interactions between some of the amino acids and water and the hydrophilic interactions between water and some amino acids, as well as acid-base interactions, hydrogen bonds, and so on. These favorable or unfavorable interactions are what makes proteins fold properly, though they do misfold at a low frequency. Some can’t fold at all and require other proteins to help them do it! And others, once misfolded, induce others to misfold, leading to deadly chain reactions (known as prion diseases).
And, of course, proteins don’t die. They aren’t alive in the first place, so that just doesn’t make any sense. A protein can happily diffuse around for a pretty long time as long as it stays in the proper buffer and temperature conditions (which vary for different proteins). Biochemists take advantage of this all the time when they purify out proteins to use for chemistry applications. Taq polymerase (used in PCR and sequencing) and restriction enzymes are excellent examples of this.
I recognize that your point is still the circularity problem, which again doesn’t make sense because it assumes that the whole thing came into existence at the same time. And actually, since pretty much the whole of evolution that people are interested in occurs after the acestral single-celled organism evolved, the circularity problem doesn’t even apply. It applies to evolution leading up to the first cell, for which all we can do is speculate because it is not possible to obtain evidence for what happened. This is a much debated problem, but one that is entirely irrelevant for the study of evolution.
Consider the following explanation from evolutionist biologist Frank B. Salisbury from American Biology Teacher, Sept. 1971, pg. 338:
Before I even read the quote, I found it telling that your source is a biology teacher and is more than 30 years old. Presumably, if this biology teacher had advanced degrees in evolution they would have been provided for support. But I digress.
“Surely our ideas about the origin of life will have to change radically with the passage of time. Not only is the gene itself a problem: think of the system that would have to come into being to produce a living cell! It’s nice to talk about replicating DNA molecules arising in a soupy sea, but in modern cells this replication requires the presence of suitable enzymes. Furthermore, DNA by itself accomplishes nothing. Its only reason for existence is the information that it carries and that is used in the production of a protein enzyme. At the moment, the link between DNA and the enzyme is a highly complex one, involving RNA and an enzyme for its synthesis on a DNA template; ribosomes; enayzmes to activate the amino acids; and transfer-RNA molecules. Yet selection only acts upon phenotypes and not upon the genes. At this level, the phenotype is the enzyme itself. How, in the absence of the final enzyme, could selection act upon DNA and all the mechanisms for replicating it? It’s as though everything must happen at once: the entire system must come into being as one unit, or it is worthless. There may well be ways out of this dilemma, but I don’t see them at the moment.”
And, after reading the quote, it is clear that I was right to be suspicious of your source. Most of what this guy says is already addressed above. You are again assuming that everything that works now had to work the same way when everything first started. There is absolutely no reason for this to be true. The trendy speculation for pre-cell evolution gives one possibility (again, all we can do is speculate since we cannot get evidence), that self-replicating RNA was the precursor. Another starts with mineral crystals. In any event, for evolution all you need is something that replicates and whose replicative abilites somehow depend on its physical qualities. Once you have that, evolution has to happen. Saying that “the process is so complicated now that I can’t possibly understand how it could have started out simply” is like looking at a stone arch and saying “if that keystone block was removed the whole thing would fall over, therefore it must have been created in one go which is clearly impossible. So god must have built that arch.” In both cases you are failing to acknowledge the wonderful instruments we call scaffolding (more metaphorical in the evolution sense). Things that were necessary to get the project going but not necessary afterwards.
In closing, please understand what you’re saying before you present it as an argument!