19 September 2005

DNA and RNA (and Birdnow).

PZ Myers has, over at Pharyngula, taken issue with a remarkably ignorant essay written by Timothy Birdnow. Birdnow has responded with a new blog, PZ has responded to part of the response, and so the fun begins. At the risk of being seen as just piling on to an easy target, there are a couple of important points that I don't think have been raised yet. The first has to do with exactly what constitutes the "building blocks of life"; the second has to do with basic competence.

Below is a quote from the exchange between Birdnow and Myers where the question of the "building blocks of life" is raised:
What, you may ask, is the connection between Einstein`s proof of atoms [his explanation of Brownian motion] and Darwinism? Darwinism argues that all life evolved from a less complex state. Following the chain of life backwards, one eventually comes to the most basic unit of life-deoxyribonucleic Acid (the DNA molecule). The DNA molecule is composed of the even simpler RNA molecule, and is the fundamental building block of life. It is the largest, most complex molecule in nature. According to Einstein`s theory, the original DNA (and RNA) Molecules should not have formed and survived since there are being constantly buffetted by energized atoms. The establishment of life required energy, and that energy meant that the nascent DNA was exposed to more energetic particles which should, logically, have prevented the formation of such a large and complex molecule. That this molecule not only formed but spread suggests different mechanism at work then those proposed by the Darwinists.

DNA is not made of RNA. They are two molecules with similar structures, but different sugar backbones and a small difference in the bases.

Oh, so now we have two completely different molecules as the building blocks of life! Life did not begin once, but twice from seperate building blocks! You know, Doctor, that DNA is fundamentally an advance on RNA. You are playing games here, and it does not disprove a thing I have said.

Both DNA and RNA are very important to life, and they are currently important for different reasons. They are also both representatives of only one of the types of molecule that are of fundamental importance to life. Both DNA and RNA are macromolecules (big molecules) made by stringing together (polymerizing) a large number of smaller molecules. DNA and RNA are both members of the class of macromolecules known as nucleic acids. Nucleic acids have three main parts: A sugar molecule, a base, and a phosphate group. DNA and RNA differ in the sugar that they use (RNA uses ribose; DNA uses a ribose that is missing an oxygen). Both use four different bases, and share three of them (adenine, guanine, and cytosine). The fourth base in RNA molecules is uracil, while the fourth base in DNA is thymine.

In addition to nucleic acids, there are also proteins, sugars, and lipids (fats). All of those are also critical to life as it now exists. Proteins are important in allowing cells to carry out chemical reactions, sugars are important for energy storage and transfer, and lipids are important in creating the barriers that separate the inside of the cell from the outside. All of these are fundamental building blocks of life as we know it.

I've stressed that these are important to current life for a reason. Just because something is critically important now does not mean that it has always been critically important. For example, the keystone at the center of an arch is totally critical to the structural stability of the arch. Remove the keystone, and the whole thing collapses. The keystone, however, is the last structural component added to an arch. Prior to the placement of the keystone, the structural stability is provided by scaffolding. After the placement of the keystone, the scaffolding is redundant, ugly, and unnecessary, and it is quickly removed.

I'm not trying to suggest that there used to be some sort of "scaffolding" that took the place of one or more of these types of macromolecule - we don't know that. I'm simply trying to point out that the current importance of nucleic acids does not necessarily imply that nucleic acids were always as important as they are now. That is one of the things that origin of life research is currently examining.

It is possible that neither DNA nor RNA was critically important to the development of life. It is possible that both were. It is possible that either (or both) were very important, but not in the same way that they are today. Right now, those aren't questions that we can answer.

What I can say, however, is that Birdnow is entirely wrong when he claims that "DNA is fundamentally an advance on RNA." DNA is better than RNA when it comes to the long-term storage of genetic information. RNA tends to degrade relatively quickly, and stability is important if genetic information is going to be reliably stored and transmitted to the next generation. RNA, however, is better than DNA at a number of other tasks. In addition to being used to take the information from DNA to the ribosomes for use in constructing proteins (messenger RNA), RNA strands also make up part of the ribosomes (ribosomal RNA). RNA is also used to collect the amino acids that are added to the protein (transfer RNA). For these tasks, a single-stranded RNA molecule works much better than double-stranded DNA.

DNA is no more of an advance over RNA than humans are an advance over the cockroach. DNA is different from RNA and does different things than RNA. Similarly, if you want a poem written or a city built, you want a human. If you want something that is likely to live through a nuclear holocaust, the cockroach is a better choice. Along the same lines, the hammer is not an advance over the wrench. Different tasks simply call for different tools - and this happens to be as true within the cell as it is at a construction site.

In addition to the misconceptions over DNA and RNA, Birdnow's uninformed diatribe also provides an illustration of a very interesting phenomenon: the tendency of people who have a minimal understanding of science to believe that they are as qualified, if not more qualified, to comment on scientific issues as professional scientists are. Let's take another look at part of Birdnow's statement:
You know, Doctor, that DNA is fundamentally an advance on RNA.
Later on in the post, he goes on to complain of part of Myers response:
This is the old ``I know more than you and I say so`` canard.
When Myers complains - entirely correctly - that Birdnow displays a massive knowledge deficit in the field of biology, Birdnow is apparently highly offended:
Boy, if that isn`t the pot calling the kettle black! The main reason I wrote this was because I became increasingly irritated with the monstrous arrogance and utter closed mindedness of Darwinists such as Dr. Myers. Perhaps, Dr., if you found this essay hard to understand you should find yourself a fifth grader to explain it to you. You don`t seem to have a command of logic.

Birdnow, who is a property manager, apparently feels that his understanding of biology is secure enough that he can tell a professional biologist what is what. Similar beliefs about the nature of science seem to be very common, as was pointed out over at Photon in the Darkness a while back. The people over at American Thinker, who posted the original Birdnow piece, seem to find this completely normal. Yet, in virtually any other area of American society, such beliefs would be considered completely ridiculous.

In fact, scientists who dare to suggest that they might be more qualified to comment on scientific matters than non-scientists run the risk of being branded as "elitists". It's not elitism, folks, it's specialization. Modern society is far, far too complex for everyone to be good at everything. Most people select career paths that are specialized fields, and they are (normally) better at their own field than they are in other fields. This means that they are (normally) better able to develop informed opinions about matters within their fields than are people who lack the strong background in that area.

I suspect that Tim Birdnow knows a hell of a lot more about property management than I do. I also suspect that when the roof is leaking at a property that he is responsible for, he calls a roofer to fix the problem, not a plumber. Yet, despite this, he thinks that he has a sufficient knowledge of biology to publicly claim that, "Any way you look at the issue, Darwinism is on the ropes."

Mr. Birdnow, if I tried to tell a plumber how to fix a sewer problem, I'd look like a fool. And rightly so. If I tried to tell you how to manage property, I'd look like a fool. And rightly so. When you try to tell me that you know more about biology than I do, you look like a fool. The truth is that, as far as anyone can tell from reading your post and response, you don't know diddly squat about biology, geology, or paleontology. Your writing is, in fact, jam packed with misconceptions, misunderstandings, and outright errors.

When I tell you that, I am not being arrogant any more than a teacher is when they point out errors in a student's test. I am presenting an evaluation of your work that I am actually qualified to make. PZ Myers is even more qualified (much more qualified) to make that evaluation. Both of us have taken numerous classes in biology, both of us have undertaken research, both of us know the field. We understand biology, and we can tell when other people don't. You don't.

Suggesting that I may be more qualified than you are to determine how well you understand biology is also not "elitism". It is specialization. The fact that I am a biologist does not make me any better or worse, in a general sense, than a butcher, a baker, a property manager, a janitor, or any other trade. It just means that I know more about biology than people who aren't biologists, and that I am, for that reason, more qualified to make statements about biology than people who aren't biologists. I don't know why so many people have a problem with that.


Anonymous said...

Period. End of story.

Great Post! Thanks!

Joe D

Anonymous said...

Good article, but one minor criticism... The Myers/Meyers Birdnow/Birdwell thing gets a little confusing...

Does anyone know if The American Thinker[sic] has weighed in on the issue? I'd like to know their thoughts about this alleged "evolutionist jihad".

TQA said...

Thanks. I think I fixed all the misspellings. My apologies to both PZ and Tim for the carelessness.

Anonymous said...

Thanks. I think I fixed all the misspellings. My apologies to both PZ and Tim for the carelessness.

Almost. Taken from the article:

"Yet, in virtually any other area of American society, such beliefs would be considered completely rediculous."

Ridiculous is spelled with an I. It's just one of those commonly misspelled words that, for me at least, tends to dampen whatever criticism preceded it.

Gerry L said...

Yes. Yes. Yes.

Interesting timing. After following the Myers/Birdnow saga this weekend, I found a letter published today in The Oregonian (http://www.oregonlive.com/letters/oregonian/index.ssf?/base/editorial/112695486618420.xml&coll=7&thispage=5) that included the sentence "The author does not appear to have done much research into the other side of the issue." But this was in a letter by a reader who had been offended by the Flying Spaghetti Monster stories and "the other side of the issue" refers to ID.

I've been doing an "in my head" response about why many scientists are so frustrated by copy/paste critiques spewed out by people who know nothing about evolution or the life sciences. But your response is much better than anything I have been noodling.

Anonymous said...

As an American, I'm embarrassed by the fact that a website named "American Thinker" indulges in such ignorant tripe. I think we should sue for defamation of Americans (and Thinkers) everywhere.

Anonymous said...

"the fourth base in DNA is thyamine."


Anonymous said...

You sell yourself far too short by saying that you would look foolish giving advice on property management. I suspect that Birdnow's property management ability could be easily surpassed in a short time by anyone with the intelligence and wilingness to learn of an average scientist.

TQA said...

I said I know something about biology. I never said that I know something about spelling. But I think I've finally got all the spelling mistakes worked out this time.

Anonymous said...

Birdnow's posts share something I've noticed at links posted at my favorite Web site, Quintessence of the Loon (no longer updated)--the loonier the poster, the longer and more insistent the post. There were always links to sites put up by high-school dropouts that were so much smarter than physicists and engineers that they could invent perpetual-motion machines.

Anonymous said...

I just read Birdnow's response to Meyer's, and the following made me crack up:

Birdnow, in his original essay, pointed out that snakes do not bear live young.

Meyers, in his response, said: "Many snakes, including the common garter snake, are live-bearers."

To which Birdnow responded: "I accept that."

What a bizarre little moment of willingness to "accept" things that are real, and not made-up by Birdnow himself. It kinda makes the rest of his responses look even more desperate by comparison.

Anonymous said...

Birdnow reminds me very much of my extended family. When relatives come to visit they try to "convert" me to creationism for fear that my profession will surely send me to Hell. I simply tell them that whereas they can believe whatever they want, they may not inflict their ideas upon me or into science classrooms.

Factual arguments are virtually useless. Anyone who will believe a 2,000 year old book over literally tons (fossils are heavy!) of scientific evidence will not listen to what you say. I focus on the children and tell them to question the world and everything anyone tells them is absolutely true.

Anonymous said...

Property manager? Why do I think slum lord? Hmm. Surely more knowledgable than a biologist on matters of cockroaches.

Anonymous said...

Good post, one quibble:

"DNA is no more of an advance over RNA than humans are an advance over the cockroach."

One could reasonably argue that humans are an advance over the cockroach, in terms of complexity or degree of divergence from the shared ancestor, or even just using an anthrocentric measure and picking us first. I know what you meant, DNA is no more complex or advanced than RNA, but one must be careful as argumentative idiots will jump on these minute aspects of argument to obfuscate the issue.

TQA said...

No, I really did mean what I said. Humans are not an "advance" over the cockroach. There are a lot of things that we can do better than the cockroach, but there are also some things that the cockroach can do better than we can.

We can pick some arbitrary and/or anthropomorphic criteria, and define ourselves to be more advanced, but that's a bit circular. Complexity gets tricky to define, and it's even harder to argue that more complex=better.

Anonymous said...

I have to agree: cockroaches are much better at eating almost anything and breeding huge numbers of offspring.

Njorl said...

"Both of us have taken numerous classes in biology, both of us have undertaken research, both of us know the field. We understand biology, and we can tell when other people don't. You don't. "

I think this is not a valid arguement for telling people they are wrong. I would not accept someone with a theology degree simply telling me that they knew the nature of god better than me because they have taken courses.

It is, however, a valid basis for telling someone they are not qualified to progress the debate beyond a certain point. It is a valid basis for telling someone that they are not equipped to understand even their own arguments, let alone yours. Essentially, you can tell people "this is beyond your understanding", but you can't say, "you are wrong". Well, yes, you can say it, and be right about it, but it won't mean anything to them.