Friday, June 1, 2007 | Science : Evolution and Biology | print version

TB and the Question of Evolution

by Deborah Blum, Huffington Post

Thanks to Mark for the link.

Reposted from:
http://www.huffingtonpost.com/deborah-blum/tb-and-the-question-of-ev_b_50123.html

deborah

I recently attended a national meeting of biologists, gathered in dismay over the way we teach medicine in the United States, at least regarding basics of biology. At the top of their list was the failure of medical schools to adequately teach principles of evolution. They blamed such ignorance for what we all face now -- an unwanted and dangerous experiment in microbe evolution.

I'm talking, of course, about the rise of antibiotic resistant bacteria. The "superbugs" are once again in the news following this week's travel fiasco, involving a Georgia man, who against the advice of his doctors, decided to fly to Europe for his honeymoon, although he was infected with tuberculosis. In fact, by the time he arrived in Italy, doctors realized that he was carrying a worst-case form of the disease called XDR TB, which is highly infectious, usually fatal, and resistant to almost all available treatment.

The man has since been hustled into quarantine in Atlanta, where the U.S. Centers for Disease Control is headquartered. The agency has stationed an armed guard outside his room. CDC is also conducting TB tests on airline personnel from his Air France flight to Europe and his Czech Air flight back to North America, in addition to trying to track down and test passengers seated near the infected passenger.

It would be easy enough to speculate at this point about human stupidity and its causes. But I don't want to dwell on the passenger in question. I want to dwell on the mycobacterium responsible for tuberculosis and why it shape-shifted into a form so potentially deadly that CDC issued its first quarantine order since 1963. (That order involved a suspected case of smallpox.)

And that, of course, brings us back to medical schools and the question of evolution. Today most doctors prescribe antibiotics sparingly but, even 10 years ago, medications were given for infection the way water is given for thirst. The result was to create a richly antibiotic-laced world, one that presented bacteria with a challenging new environment. And microbes responded by adapting, evolving to meet its pressure. The problem (for us) was not the bacteria that died, but the ones that contained mutations that allowed them to survive. The survivors reproduced. Challenged by another drug, they died back except for a few resistant to both chemical agents. And that scenario repeated itself to create our current problem. To use TB as an example, there are now more than half a million people infected with multiple-drug resistant tuberculosis.

I am somewhat overstating the doctor's responsibility here because the problem was -- as is -- complicated by patient compliance -- which simply means that people don't take the drugs as ordered, cut back too soon, allow the bacteria population to bounce back, newly energized and more resistant.

But it's impossible to overstate the evidence for evolution at work in this dilemma. If we were half as good as bacteria at evolving to meet challenges, we'd probably now rule the universe. In fact, bacteria are such wonderfully adaptive creatures that biologists are now conducting "experimental evolution" tests with common species such Escherichia coli -- commonly referred to as e. coli - which thrive in the human gut. The editor of Physiological and Biochemical Zoology, which plans to publish those studies this summer, exults that "Now, we can study evolutionary change as it is happening."

So for all of you who don't believe in the principles of evolution, who don't get the idea that evolution is, among other things, a foundation of smart medicine, I suggest you visit Grady Memorial Hospital in Atlanta and check out the room with the armed guards. Maybe you'll learn something.

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1. Comment #46771 by Reg on June 1, 2007 at 2:02 pm

It is more than likely that the guard is himself an anti-evolutionist.

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2. Comment #46774 by Reg on June 1, 2007 at 2:06 pm

Oops sorry, I left out - or herself.

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3. Comment #46783 by bornabaptist on June 1, 2007 at 3:18 pm

Evolutionary Biology should become a required academic class in every U.S. university. I am a physician and do not remember ever studying the subject in elementary, secondary, university or medical school. I knew about the theory but it was not until I read The Selfish Gene that I understood and appreciated the elegance and truth of Darwin (and R. Dawkins). I know, I have led a sheltered life. It is what it is in middle America, truth is something you have to seek for yourself.

I feel certain that RDF can help remedy the poor teaching of evolution within U.S. universities. Within a generation, would it not be great if every university graduate had read and understood The Selfish Gene, The Extended Phenotype and others?

Curiosity acted upon, leads to wisdom.

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4. Comment #46790 by maton100 on June 1, 2007 at 4:12 pm

I have a rare case of impetigo that has been resistant to over two oral antibiotic medications in the last three months. The sleep of reason does produce monsters. Wake up and stop praying!

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5. Comment #46800 by roach on June 1, 2007 at 5:10 pm

I agree with bornabaptist.

Everyone should be taught evolutionary biology. It is THE answer that explains why we are here. I was a political science major and I wish I would have been taught evolution properly. I continue to be fascinated by what it reveals about the human condition. It's a shame that the beauty of evolution isn't praised and pressed.

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6. Comment #46802 by BAEOZ on June 1, 2007 at 5:41 pm

I think we all need a good science education, especially evolution. I just read a book called "crimes against logic", which was so good I read it in a few hours. I think everybody should be taught to understand logic and to see woolly thinking too. I just visited a blog on a local newspaper http://blogs.theage.com.au/thereligiouswrite/archives/2007/05/the_great_debat.html
which recently started and let some guy have it, who was spouting stuff about evolution not explaining how life began, how it's full of inconsistencies. I didn't bother debating his point, just said he obviously hadn't bothered to read the most basic evolutionary textbook and had no idea that abiogenesis is not evolution etc. It's a pain in the arse when you get people who haven't even bothered to read, much less understand evolution. Still, he probably was indoctrinated from birth that evolution was evil. Charles Darwin was the devil incarnate and Richard Dawkins his archdemon.......

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7. Comment #46804 by Duff on June 1, 2007 at 5:47 pm

If anyone out there thinks the Brownback pablum published in the New York Times is an innocent attempt to smooth over the "innocuous division" between religion and science, they should think again. Drug resistant bacteria will eventually be controlled, if science is allowed free reign, but if religious ideologues like Brownback are voted into office, science will be brought to heel by the religious who want it to conform to their simplistic concepts and any research that is"evolutionarily tainted" will end. Never miss an opportunity to confront an iron age wanker!

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8. Comment #46811 by Dr Benway on June 1, 2007 at 7:02 pm

You don't have to be an evolutionary biologist to understand how antibiotics and other interventions pressure infectious organisms over time. You just have to think like a bug, and you need to understand the host-parasite environment.

Imagine you're malaria. You want to "be fruitful and multiply," as the Lord commanded. To do that, you need a human host. To move from one human to another, you need a mosquito.

If you're a nasty bug, you make your host very sick or you kill him. If you're a nicer bug, you just make him a little bit sick, or not sick at all. Which strategy works better for you? Well, that depends on the behavior of your human hosts and your mosquito vectors.

Imagine a society of loners who never leave the house except when seriously ill, when they're sent to a hospital. As a malaria bug, you ought to make your host very sick so he's sent to the hospital, where you'll have a greater chance of jumping from one host to another.

Imagine a more normal society of sociable humans. The humans go outside daily, except when sick, when they're home in bed. In this environment, you ought to avoid making your host so sick he doesn't go outside.

One of the simplest ways to pressure the malaria parasite toward a less virulent form would be to install screens on the windows of all homes in malaria infested areas. Screens mean less interaction between human hosts and mosquito vectors. In a well-screened environment, parasites that cause only mild symptoms will out-compete nastier versions that keep people home in bed.

An ecological viewpoint, one that appreciates not just an organism, or a species, or a particular resource such as clean water, but an entire, interdependent ecosystem, seems to be over-looked not only in medicine, but in many public discussions. Perhaps that's because we have more specialists than generalists among us.

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9. Comment #46816 by BAEOZ on June 1, 2007 at 7:34 pm

You don't have to be an evolutionary biologist to understand how antibiotics and other interventions pressure infectious organisms over time. You just have to think like a bug, and you need to understand the host-parasite environment.

Ok, now are you suggesting bugs think and therefore are not adapting to their niches? Because that's absurd. You example of malaria certainly suggest evolution. I'm going to "play a straight bat" to this and let you tell me whether you're being cute or actually trying something else.
Over to you good Dr.

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10. Comment #46819 by Dr Benway on June 1, 2007 at 7:59 pm

By "think like a bug," I just mean appreciate options for self-replication from the standpoint of the bug.

Some like to whistle; some like to paint. I like to anthropomorphize.

Yes, the bug view is about natural selection. But the concept is so simple. I don't think a person needs to take courses in evolutionary bio to grok it. That's all I'm saying.

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11. Comment #46821 by steveroot on June 1, 2007 at 8:15 pm

Of course bacteria, parasites, viruses and such do not think. But they are useful in considering evolution because their generation time is so short... and, unlike embryos, no one cares if you mistreat 'em a bit!
Steve

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12. Comment #46826 by BAEOZ on June 1, 2007 at 9:31 pm

Dr Benway, I humbly petition pardon. From now on we shall say bugs think about their lifestyle choices as christians say homosexuals do....Just kidding.

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13. Comment #46844 by Lagomort on June 1, 2007 at 11:57 pm

None of this is going to change the mind of a creationist. They believe this is still well within "Kind" microevolution. If one wants to try and show evolution to a fundamentalist, you need a lot more than the above...

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14. Comment #46944 by CJ on June 2, 2007 at 10:30 am

One of the oft trotted out arguments against the "theory" of evolution is that "You can't see it in the lab or do experiments on it". Well that would now appear not to be the case. Bookmark this article for future use. It's just rather unfortunate that so many people have already died and will continue to die as a result of the lack of respect for the scientific method and one of its most important results.

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15. Comment #46982 by roach on June 2, 2007 at 2:16 pm

I saw a funny line about micro/macroevolution once. It went something like this:

"Go ahead and tell me why microevoloution can't become macroevolution right after you tell me why I can't walk 1,000 miles one step at a time"

Does anyone with a firm understanding of evolution think this is a fair analogy?

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16. Comment #46987 by Nails on June 2, 2007 at 2:38 pm

Sounds good to me.
But really you need to make a distinction of it being one short step at a time, no matter how long it takes.
Time it really the key here, when you have millions and millions of generations then small steps are all you need.

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17. Comment #46991 by denoir on June 2, 2007 at 2:44 pm

roach:
Not when the bozos claim that the earth is 6,000 years old. Essentially, to use your analogy, they claim that you can't walk 1,000 miles because the total available distance is 85 inches. (85 inches to 1000 miles is what 6,000 years is to 4.5 billion years).

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18. Comment #47006 by Friggertool on June 2, 2007 at 5:03 pm

I was taught in my first year while training as a dental surgeon that antibiotic resistance was a real threat and that prescriptions for a/bs should only be issued when absolutely necessary. That was in the late 70's.

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19. Comment #47038 by Lagomort on June 2, 2007 at 10:37 pm

Some of you still don't seem to get it (others obviously do).

To a creationist, such changes as mentioned above only mean variation within a "Kind", and are accepted. Bacteria to modified bacteria is variation of a kind. There is nothing that they do not really accept here (well one thing, but that is a different aspect of their debate).

You have to show something they consider one "Kind" breaking away and becoming another "Kind". If you do not show them that, then everything you say is just, "Blah, Blah Blah, Ginger!" to them...

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20. Comment #47156 by jvc on June 3, 2007 at 7:42 am

"Blah, Blah Blah, Ginger!"

How many people do you think took that reference?

To the dentist: It's important that doctors know that, but do their patients? If people really believed in(and thought about) evolution by natural selection, they would probably be more motivated to keep taking their prescriptions even after they started to feel better. It would also probably help if physicians spent more than 45 secs per patient, and actually explained some of this.

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21. Comment #47161 by Dr Benway on June 3, 2007 at 8:45 am

Lagomort:

You have to show something they consider one "Kind" breaking away and becoming another "Kind". If you do not show them that, then everything you say is just, "Blah, Blah Blah, Ginger!" to them...

We see species. But if we could see everything that ever lived, we'd see a continuum of life rather than discrete kinds of life.

The species concept is much like racial difference. Blacks and whites seem like separate races. But if you walk south from Europe to Africa, you'll appreciate more of a phenotypic continuum.

"Blah, blah, blah Ginger!" I use this a lot myself. Along with "Bummer of a birthmark, Hal."

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22. Comment #47164 by Logicel on June 3, 2007 at 9:26 am

Proponents of intelligent design deny substantial evidence that macroevolution has taken place. Excerpted from Jerry Coyne's excellent article (http://richarddawkins.net/article,1058,The-Case-Against-Intelligent-Design-The-Faith-That-Dare-Not-Speak-Its-Name,Jerry-Coyne-edgeorg) posted here previously:

Take one example: the link between early reptiles and later mammals, the so-called mammal-like reptiles. Three hundred fifty million years ago, the world was full of reptiles, but there were no mammals. By 250 million years ago, mammals had appeared on the scene. (Fossil reptiles are easily distinguished from fossil mammals by a complex of skeletal traits including features of the teeth and skull.) Around 275 million years ago, forms appear that are intermediate in skeletal traits between reptiles and mammals, in some cases so intermediate that the animals cannot be unambiguously classified as either reptiles or mammals. These mammal-like reptiles, which become less reptilian and more mammalian with time, are the no-longer-missing links between the two forms, important not only because they have the traits of both forms, but also because they occur at exactly the right time.

One of these traits is worth examining in detail because it is among the finest examples of an evolutionary transition. This trait is the "chewing" hinge where the jaw meets the skull. In early reptiles (and their modern reptilian descendants), the lower jaw comprises several bones, and the hinge is formed by the quadrate bone of the skull and the articular bone of the jaw. As mammal-like reptiles become more mammalian, these hinge bones become smaller, and ultimately the jaw hinge shifts to a different pair of bones: the dentary (our "jawbone") and the squamosal, another bone of the skull. (The quadrate and articular, much reduced, moved into the middle ear of mammals, forming two of the bones that transmit sounds from the eardrum to the middle ear.) The dentary-squamosal articulation occurs in all modern mammals, the quadrate-articular in modern reptiles; and this difference is often used as the defining feature of these groups.

Like earlier creationist tracts, Pandas simply denies that this evolution of the jaw hinge occurred. It asserts that "there is no fossil record of such an amazing process," and further notes that such a migration would be "extraordinary." This echoes the old creationist argument that an adaptive transition from one type of hinge to another by means of natural selection would be impossible: members of a species could not eat during the evolutionary period when their jaws were being unhinged and then rehinged. (The implication is that the intelligent designer must have done this job instantaneously and miraculously.) But we have long known how this transition happened. It was easily accomplished by natural selection. In 1958, Alfred Crompton described the critical fossil: the mammal-like reptile Diarthrognathus broomi. D. broomi has, in fact, a double jaw joint with two hinges: the reptilian one and the mammalian one! Obviously, this animal could chew. What better "missing link" could we find?

But these buffoons are looking for the crocoduck whose imagined image was waved high in the air by Kirk Cameron during his presentation during the debate with the Rational Response Squad.

EDIT: The proponents of ID were soundly defeated at the Dover Trial, and their pathetic denial of evidence for macroevolution was highlighted. The court was presented with overwhelmingly substantial and comprehensive evidence that evolution is a scientific theory of significant explanatory and predictive potency, while ID was nothing but Goddidit dressed up in make-believe science garb. Unfortunately, these nuts will most likely wage another court battle sometime in the future, as the Dover one was the third big legal spat in the history between the on-going battle between the IDiots and proponents of evolution. Nothing, no proof of neither micro nor macroevolution will get them to abandon their nonsense; only the strength and validity of evolution will protect America from being subjected to the mandatory teaching of ID in science classes.

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23. Comment #47169 by Lagomort on June 3, 2007 at 9:40 am

Dr. Benway,
What you are referring to is geographical variations within a cline. What creationists want is to see the development of novel characteristics that would have one separate one aspect of the population from the other into a separate "Kind". Though this term is tricky as well as relative, the above does not fit into this definition well at all...

See, as you know, bacteria can be transformed by picking-up bits of DNA and adding it to their own. They can pick-up whole plasmids with antibiotic resistance that they did not have before from other strains not even that closely related to them. What is key here is that the plasmid, in most cases observed, already contained the genes for the resistance, and they were not developed in a novel manner.

Now, to a creationist, proving to them that a novel set of antibiotic resistant genes evolved purely by modification of other genes, or better yet, unrelated DNA sequences (Or the modification of RNA reverse transcriptase viral input by mutation alone,...tautomeric shifts,... Holiday junctions mismatches...point mutations ...etc...etc...) is extremely difficult to do. While we may say these are new situations, so abilities are therefore new and novel (as in the ability of some bacteria to breakdown modern synthetics) a creationist will just claim the strain has just picked-up the required tools from several other prokaryotic sources (which we know bacteria continue to try and do) and added them to their own DNA over time while we placed selection events upon them giving us this particular end result...

I do believe, if one looks at the literature involved, and the experiments done, we can see novel gene development in prokaryotes, however, even if ones proves that case, it does not go against their claim that all evolution is micro, and within "Kinds". Since they are not disputing that, the above gives little evidence for anything against their argument.

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24. Comment #47170 by Corylus on June 3, 2007 at 9:41 am

Huh?

What's wrong with being ginger??

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25. Comment #47177 by Logicel on June 3, 2007 at 10:38 am

I want a teeshirt with the following slogan:

Diarthrognathus broomi has been sweeping the Creationist denial of MACROEVOLUTION into the dust bin of inanity since 1958.

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26. Comment #47183 by Lagomort on June 3, 2007 at 11:06 am

Diarthrognathus is actually known as Pachygenelius now, and yes, it is a great example of an obvious transitional. So are the Morganucodontids that are usually placed under Mammaliformes for reasons that still confuse me. Thrinaxodon is one of my favorites for a form that is obviously basal to both if we are going by implied trend, but, though there are almost endless such examples, there are a few problems...

First, these have nothing to do with the above example given which would be considered within "Kind".

Next, creationist deny these as transitional due to simple variation of extinct organisms where we make claims by forcing anything we see into a transitional series...

How do we show that this is false?

Well, most creationists will avoid defining what a transitional is, and hold up croco-duck pictures. You need to hold your ground and ask them, since we are dealing with fossils which are usually skeletal in nature, "What should the osteology of a transitional look-like bone-wise?"

To do this, we must ask them to explain the osteology (basically the bone morphology and how it relates to the traits of the animal) of "C", the derived form, as well as "A", the basal group from which C is said derived, and then by way of this, we need them to tell us what they think "B" (the transitional) should look like.

At this point we usually find the creationist knows little to nothing about these issues, but they may try and avoid the issue in numerous ways, including stating misunderstandings of evolutionary terms like "mosaic" (usually by misquoting Gould). At this point you need to as them to back-up their misconception claims about what evolutionary biology says by asking them for references to their said claims. When they give you mined quotes, you need to then ask for the original statement in context.

Once this is done, you can go over, not just one detail, like post-dentary development into middle ear auditory functions, but dental developments of incisors, canines, molars, cusps, occlusion, secondary palate development, loss of particular cranial elements, the development of the enclosed mammalian braincase, atlas axis development, lumbar development, digit reduction, etc...

In the end, you make them answer to you, and do not let them run around in circles. No one can know everything, as is obvious, so a creationist will simply run to another topic when they see you might answer a question given. They will do this until they find a subject you do not know about, and then claim victory by your particular ignorance of this new subject...

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27. Comment #47185 by Logicel on June 3, 2007 at 11:18 am

Lagomort wrote: Diarthrognathus is actually known as Pachygenelius now,...
______

Damg, can't the taxonomists leave a great name alone? Is it still Pachygenelius broomi?

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28. Comment #47186 by Logicel on June 3, 2007 at 11:23 am

Lagomort, thanks for the great comment/advice. I think you should become the resident evo tutor/advisor for the Rational Response Squad.

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29. Comment #47188 by Dr Benway on June 3, 2007 at 11:42 am

Corylus:

What's wrong with being ginger??

It's a Far Side cartoon reference. I googled for a link to the cartoon, but no go. However I ran across this bit from http://en.wikipedia.org/wiki/The_Far_Side that I must share, although it pertains to nothing:

As the two cartoons The Far Side and Dennis the Menace were published side by side, the captions were mixed up on several occasions, to what Larson believes to be both positive but most bizarre results. One is when three snakes are sitting down to dinner, when the youngest one complains "Not Hamsters Again!" This however was printed underneath the DTM cartoon, which portrayed Dennis and his friend eating sandwiches, while his mother is busy on the phone with the caption being "Lucky I learnt how to make peanut butter sandwiches or we would have starved to death by now," which was to appear as the Far Side's caption.

Wait, maybe the misprint story is relevant. It's an example of random mutation leading to improvement, in this case of a rather trite Dennis the Menace bit.

Lagomort:

What you are referring to is geographical variations within a cline.

I'm saying that the distinctions between species would look as fuzzy as variations within a cline if we could view all of life, past and present, at once. Once we've mapped the genomes of most known species, we'll see the degrees of relationship clearly and the continuum of life will be undeniable.

Natural selection is a general, self-evident, explanation for phenotypic changes observed over time. The distinction between big changes and little changes is arbitrary and indefensible. Many little changes will eventually add up to big changes. How can things be otherwise?

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30. Comment #47194 by Lagomort on June 3, 2007 at 12:19 pm

"Damg, can't the taxonomists leave a great name alone? Is it still Pachygenelius broomi? "

Yes, I do believe it is. The changes usually occur for two reasons.

1. The genus name was already being used somewhere else and they were unaware when they named the fossil...

2. They realize the newly named species was already found before time and had a different name. This is usually the case when different parts of the animal are first found, then more is found that shows a link indicating they were actually one species, not two...

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31. Comment #47196 by Lagomort on June 3, 2007 at 12:29 pm

"Natural selection is a general, self-evident, explanation for phenotypic changes observed over time. The distinction between big changes and little changes is arbitrary and indefensible. Many little changes will eventually add up to big changes. How can things be otherwise?"

Actually, most organisms are relatively stable over time. The changes we see as representing differences of "Kind", like early ungulate to whale transitions or theropod to volant theropod, happen rather quickly geologically speaking, and are not really the accumulation of tiny changes. This is why Gould and Eldridge proposed the idea of Punk Eek.

What a creationist desires is to be shown a novel trait being developed that could be used to separate a group based on "Kind" when the above article only shows selections on already existing traits.

In other words, they do not care about seeing hair becoming short, or hair becoming curly and red, but, however, desire to see the development of something like hair itself where there was none before...

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32. Comment #48014 by Oldchemist on June 6, 2007 at 9:24 am

In relation to the malaria story, it's interesting that our life-style generates new niches for infections to develop and spread. On long-haul flights you sit nearer to other people and for a longer period than you do in cinemas, buses or trains. The Cholera pandemic of the late 1820s and early 1830s arrived in England by sailing ship after crossing Asia and Europe at walking speed. Now it would arrive in a jumbo jet in a few hours.

In the pharmaceutical industry in the 1970s and 1980s micro-biologist did deliberate "evolution" of micro-organisms to improve on the process that led Fleming to discover penicillin. When an organism was found that produced small quantities of a substance with antibiotic activity, it was grown on petri dishes and irradiated with UV light at a level that would kill about 90% of the cells. The survivors were then allowed to grow again to see if they made a greater amount of the antibiotic or a different one with superior properties. The UV irradiation knocked out one or more of the genes for the various enzymes involved in the synthesis and/or degradation of the antibiotic substance.

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