The Corpus Callosum

Antibiotic Resistance Not Evolution?

This is strange.  A person with a Ph.D. in
molecular genetics, href="http://www.answersingenesis.org/events/bio.aspx?Speaker_ID=52"
rel="tag">Georgia Purdom, wrote a post in which
she claims to have shown that the development of antibiotic resistance
in bacteria is not an example of evolution.

href="http://www.answersingenesis.org/articles/am/v2/n3/antibiotic-resistance-of-bacteria">Antibiotic
Resistance of Bacteria: An Example of Evolution in Action?

by Georgia Purdom, Ph.D.
July 10, 2007

The extraordinary ability of certain
bacteria to develop resistance to antibiotics—which are
otherwise useful in speeding recovery from some illnesses—has
been a hot topic on the minds of doctors, hospital staff, reporters,
and the general public for several years. It is also heralded as a
textbook example of evolution in action.

These bacteria are being studied by evolutionary scientists with the
hope that they will reveal secrets as to how molecules-to-man evolution
could have happened.

But are bacteria really evolving?…


Dr. Purdom then makes several errors:

Although the mutant bacteria can survive
well in the hospital environment, the change has come at a cost. The
altered protein is less efficient in performing its normal function,
making the bacteria less fit in an environment without antibiotics.
Typically, the non-mutant bacteria are better able to compete for
resources and reproduce faster than the mutant form.


She waffles a bit on this point, so I can’t say she is 100% wrong.
 Typically, the mutated bacteria are at a disadvantage in an
antibiotic-free environment.  But not always.  The
exceptions can be hugely important, though.  It is not
appropriate to downplay them.  

Bacteria can also become antibiotic
resistant by gaining mutated DNA from other bacteria. Unlike you and
me, bacteria can swap DNA. But this still is not an example of
evolution in action. No new DNA is generated (a requirement for
molecules-to-man evolution), it is just moved around.


This is just silly.  Evolution does not
require that new DNA be created.  Plus, when she acknowledges
that mutations can occur, she acknowledges that new DNA can
be created.

Mutation and natural selection, thought to
be the driving forces of evolution, only lead to a loss of functional
systems. Therefore, antibiotic resistance of bacteria is not an example
of evolution in action but rather variation within a bacterial kind.


Mutation and natural selection are two of the
mechanisms of evolution, but they are not the only ones.  The
statement that they only lead to the loss of functional is simply
unsupportable.  The statement, about antibiotic resistance not
being an example of evolution, does not follow at all from the
preceding statements.

The strange thing about this is that she really ought to know better.
 In fact, it is difficult to believe that she does not.
 Yet, the statements indicate that she does not understand
evolution at all.  She could state that the type of evolution
observed when bacteria evolve antibiotic resistance via DNA swapping
does not explain the origin of species.  If she stopped there,
she would be fine.  But when she tries to extend the argument,
the whole argument falls apart.

HT: href="http://hjhop.blogspot.com/2007/09/logic-resistant-strain-of-aig-virus.html">Happy
Jihad’s House of Pancakes.

Comments

  1. #1 Bing McGhandi
    November 15, 2007

    Thanks very much for the link!

    HJ

  2. #2 stumpy
    November 15, 2007

    I wish that the flat earth, intelligent design people would have the honesty to just come out and say, “There is no evolution — it’s all magic”. (If they wished, they could do the same thing with experimental physics, chemistry, and other branches of science as well.) But, instead, they keep trying to fool themselves and others into accepting a twisted interpretation of a narrowly selected set of observations, with the goal of imposing their superstitious dogma on everyone. As hundreds of others have said, it’s the opposite of scientific inquiry.

  3. #3 Nebularry
    November 15, 2007

    One thing is certain, the IDiots at the Discovery Institute will latch onto this and get LOTS of mileage out of it. Too bad!

  4. #4 Moopheus
    November 15, 2007

    “Although the mutant bacteria can survive well in the hospital environment, the change has come at a cost. The altered protein is less efficient in performing its normal function, making the bacteria less fit in an environment without antibiotics.”

    I am not a biochemist, but I don’t understand how this is supposed to mean it’s not evolving. If the bacteria is adapting to an environment that includes antibiotics, why would it matter if that adaptation wasn’t necessarily very good in a different environment? Isn’t that kind of like saying animals adapted to living in the air on dry land at the cost of being able to live in the water, except for a few?

  5. #5 whitney
    November 15, 2007

    I’m not competent to judge her on the biology, but the language she uses is easily recognizable as that of evolution denialists (kinds, evolution = generation of new DNA/information, etc.)

  6. #6 bob henderson
    November 15, 2007

    So let me see if I understand: Some bacteria have changes to their DNA (by both mutation and DNA swaps), are therefore better adapted to their environment (presence of antibiotics) and therefore become the dominant population. And this IS NOT evolution.

    One would hope for better from OSU but at least they have good football teams. I would not hope for any better from someone who is an “AiG (answers in genesis)-US speaker, researcher, author and online instructor”

  7. #7 Ilya
    November 15, 2007

    That last paragraph you quote from the article is insanity. Not just unsupportable, but flat-out wrong.

  8. #8 Tara C. Smith
    November 15, 2007

    Purdom works for Answers in Genesis (where the story is hosted), the major young earth creationist organization in the U.S. This is what she does: use her degree to lend some “authority” to creationism. She’s also not a microbiologist, though she tries to pass herself off as one, and I believe she’s supposed to have a forthcoming book on it as well.

  9. #9 Julie Stahlhut
    November 15, 2007

    Whitney: Never fear. The phenomenon she’s describing (bacteria taking up DNA from external sources) is called “recombination” or “horizontal gene transfer”, and it’s a common source of genetic variation in bacteria. It’s also a fruitful topic in evolutionary research. (I work on a similar system myself.)

    Dr. Purdom is claiming that “moving DNA around” is not true evolutionary change. But, by every accepted definition, it is evolutionary change. Like mutation, recombination is a source of genetic variation that can be inherited by descendants of the affected cell, and it can influence the survival and reproduction of those cells in some environments.

    There’s a page for her at Answers In Genesis (link not provided; it’s easy to find) that claims she has a Ph.D. in molecular genetics, but either she doesn’t understand what evolution is, or else she’s deliberately trying to confuse her audience. In order to avoid making an argument from incredulity, I’ll leave further conclusions up to the reader.

  10. #10 Jason Failes
    November 15, 2007

    Oh, yeah, “molecules-to-man”, “no new information is created”, “variation within a bacterial kind”
    Just take off the science mask and come out of the creationist closet already.

  11. Mutation and natural selection, thought to be the driving forces of evolution, only lead to a loss of functional systems. Therefore, antibiotic resistance of bacteria is not an example of evolution in action but rather variation within a bacterial kind.

The site is currently under maintenance and will be back shortly. New comments have been disabled during this time, please check back soon.