A clever little two-step

Baym et al. 2016 Fig. 1B

Figure 1B from Baym et al. 2016. Experimental evolution of antibiotic resistance in E. coli bacteria. Bacteria were inoculated at both ends of the plate and evolved to tolerate the initially deadly concentration of antibiotic in the middle.

It’s possible for something to be both true and misleading. Here’s a great example. Frank Sherwin, a Research Associate at the Institute for Creation Research, recently wrote,

Evolutionists list antibiotic resistance as evidence of evolution, but in reality it has nothing to do with the origin of antibiotic resistance genes—let alone novel bacterial species.

Each of those things is true, but the sentence still manages to be misleading. Evolutionary biologists do regard antibiotic resistance as evidence of evolution. Real-time observations of the evolution of antibiotic resistance, like those in Michael Baym’s experiment, demonstrate evolution in action. Those experiments do have nothing to do with the origin of novel genes or of speciation. I’ve just admitted that both parts of the sentence are true, so what’s the problem?

It’s the but.

“But” implies that there’s a conflict between the two parts of this compound sentence. There isn’t. Evolution is heritable change over time. Experiments like Baym’s demonstrate heritable change over time (as have many other experiments before). To deny this would be perverse. That there was change over time is obvious from the fact that the bacteria gained the ability to survive previously deadly concentrations of antibiotic. That that change was heritable was demonstrated by sequencing the DNA of the evolved bacteria and identifying the exact mutations that contributed to the antibiotic resistance.

None of this has anything to do with the evolution of novel genes or speciation. Those would also be evolution, but they’re not the only kinds of change that are. Speciation and novel genes are evolution, but not all evolution is speciation or novel genes. All apples are fruits, but not all fruits are apples; see how that works?

It’s a clever little two-step, making two true statements and setting them up as if they’re in opposition. It might not be intentional, though. Many creationist, including cdesign proponentsists, apply a more restrictive definition of evolution (though exactly what would qualify is rarely made explicit), allowing them to look at ironclad evidence of heritable change over time and say that it’s not REALLY evolution (no true Scotsman, anyone?). This is probably what led Cornelius Hunter, whose claimed “expertise is specifically in evolution,” to drop this howler (incidentally, in response to the Baym et al. experiment):

…”evolve” is not the correct term. The microbes adapted.

Speaking of howlers, Mr. Sherwin continues:

Clearly, there can be a change in the frequency of antibiotic resistance genes, but this has nothing to do with the origin of new useful genes allegedly developed by mutation and natural selection. Creationists maintain resistant forms were already present. This was just ordinary variation within kind and recombination. Indeed, antibiotic-resistant bacteria was found in the frozen bodies of explorers over a hundred years before medical antibiotic use.

First of all, change in the frequency of antibiotic resistance genes IS evolution, but that’s not the real facepalm here. Sherwin is clearly implying that antibiotic resistance couldn’t have evolved before medical antibiotic use. I’ve already responded to a similar confusion by Phillip Cunningham, so I’ll just quote that post here:

Boom, game over, creationists win, right? I mean, how can antibiotic resistance have evolved millions of years ago if Alexander Fleming didn’t invent penicillin until 1928?…

Fleming didn’t invent penicillin, he discovered it. Penicillin, like a lot of antibiotics, is produced by a living organism, in this case the mold Penicillium. Why has antibiotic resistance been around for millions of years? Because antibiotics have been around for millions of years (probably billions in both cases).


Stable links:

Baym, M., T. D. Lieberman, E. D. Kelsic, R. Chait, R. Gross, I. Yelin, and R. Kishony. 2016. Spatiotemporal microbial evolution on antibiotic landscapes. Science 353:1147-1151.


  1. rjdownard says

    Since Hunter and Sherwin are bumping off actual science work (Sherwin secondarily referencing https://www.frontiersin.org/articles/10.3389/fmicb.2018.02458/full) I’m adding those to my TIP data field. The similarity of their views shows how deep-seated this is in antievolutionism, involving a failure to pay attention to what does cause evolution, and tunnel-visioning in on specialized examples until it just looks like the “adaptation” their dogmas can handle.

    Bacterial mutations in the Lenski work is a big topic in the new “The Rocks Were There” book I’m coauthoring, and this posting is a relevant one to include as a note, Thanks Matt 🙂

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