Darwin Demo Falls Short

What the new “evolution in action” experiment lacks in Darwin support is compensated by its propaganda value.

A cursory look at a story in The Atlantic would lead readers to suspect that the creation-evolution debate is over, and Darwin won. You can even watch the victory lap in the embedded video clip. Bacteria at both ends of a rectangular grid, made out like a football field, race to the midline, overcoming antibiotics first 10, then 100, then 1000 times the strength needed to kill them. It’s survival of the fittest! Send this demo to the classrooms of America:

Beyond any applications in research and medicine, the MEGA-plate also makes for a wonderful teaching tool. It makes the abstract concrete. It vividly brings the process of evolution to life—and to view. “We’re visual creatures,” says Baym. “Seeing is believing.”

When Michael Baym and Tami Lieberman of Harvard shared the video at an evolutionary conference last month, their colleagues were instantly cured of lockjaw:

…many attendees were awed and slack-jawed. “It’s exciting, creative and, game-changing,” says Shelly Copley from the University of Colorado, one of the organisers. Baym himself, who has seen the movies hundreds of times, is still blown away by them. “You can actually see mutations happening,” he says, before shaking his head and smiling.

The results were published in Science Magazine under the title, “Spatiotemporal microbial evolution on antibiotic landscapes.” Does a closer look at the methods and results vindicate Darwin? The “evolution” of antibiotic resistance is nothing new. ID advocate Michael Behe discussed it at length in his second book, The Edge of Evolution. He showed that in ideal test conditions—the evolution of malarial parasite resistance to chloroquine and other chemicals—Darwinian evolution was incapable of crossing fitness landscapes requiring more than two coordinated mutations. Malaria parasites could sometimes survive antimalarial drugs, but only by “throwing stuff overboard” – i.e., engaging in desperate attempts to survive through loss of information. (By analogy, a criminal can evolve resistance to handcuffs by having his hands cut off.)

To succeed in demonstrating Darwinian evolution, Baym would need to show (1) realistic starting conditions, (2) the unguided emergence of new genetic information, (3) positive selection, (4) fitness increase over wild type, (5) speciation, (6) some innovative heritable structure capable of leading to new branches of organisms, and (7) successful competition of the winners in the real world, alongside other organisms in the ecology. Let’s examine the paper for these requirements.

Realistic starting conditions? The Materials & Methods section shows that they used a “strain from the Keio collection of E. coli K-12 BW25113 knockout variants.” The platform on which the experiment was run was highly artificial, consisting of purified agar, with several rounds of artificially-selected bacteria as starters. The environment contained no other organisms that wild E. coli were likely to encounter in the wild.

New genetic information?  The authors discuss mutations, but there is no mention of beneficial mutations or gain-of-function mutations. Michael Behe claims at Evolution News & Views that over half the identified mutations amount to loss of function. The others are likely deleterious as well:

The key to understanding the paper is its Figure 3C. There it shows the genes that have undergone more than one mutation across tested bacteria. They break the mutations down into silent changes, changes of amino acids (point mutations), and insertion-deletion or nonsense mutations, which almost certainly are loss of function (LOF). Over half of genes contain such LOF mutations, along with some point mutations, which likely also degrade or destroy function. In other words, devolution.

Positive selection?  There is no mention of positive selection in the paper among the 11 mentions of the word. Nor is there mention in The Atlantic.

Fitness increase?  There is no mention of fitness increase in the paper among the 5 words “fit” or “fitness” and no mention of the word in The Atlantic.

Speciation?  The organisms at the beginning and end of the experiment are still not only E. coli, but descendants of the original strain of E. coli.

Innovation?  The word “innovation” is lacking in the paper. The word “novel” is only mentioned as a possibility for future experiments: “Owing to the relaxed evolutionary constraints in range expansion dynamics, the MEGA-plate is likely to reveal novel mutational pathways to high-level multiantibiotic resistance.” In a companion piece in Science, Luke McNally and Sam P. Brown claim innovation, but provide no specifics: “The advent of evolutionary innovations via mutation and the subsequent selection of these mutants are thus imprinted on the plate, providing an unprecedented visualization of evolution through time and space.” The innovation, however, is merely inferred from the fan-shaped patterns on the advancing fronts of resistant strains.

Competition in the wild?  No mention is made of releasing the winning germs back into the wild to see if they could survive and proliferate in real-world conditions against their less-evolved progenitors. McNally and Brown admit this: “the MEGA plate could be criticized as merely a caricature of real-world environments, but such a perspective misses its value as a tool to elucidate the fundamental principles of evolution in a spatial environment.” Surprisingly, they also consider Lenski’s Long-Term Evolution Experiment (LTEE) with E. coli to be vulnerable, too: it “could be similarly criticized for being unrealistic yet has provided key insights into the longterm bounds of evolutionary fitness and the dynamics of evolutionary innovations, among many other discoveries.” But if they are both unrealistic caricatures, how can they provide insight? Maybe it’s just in the propaganda arena.

Propaganda Value

The true significance of this paper is its visualization potential to promote evolution to unsuspecting students. Baym’s statement “seeing is believing” makes that clear, but the last sentence in the paper is even more explicit:

Its relative simplicity and ability to visually demonstrate evolution makes the MEGA-plate a useful tool for science education and outreach.

In short, a visual aid that demonstrates nothing of Darwinian evolution can nonetheless serve as a “useful” teaching tool to promote Darwinian theory. Useful to whom? “In other words, the MEGA-plate does not correspond to the real world and may be irrelevant to medicine,” Behe says. “Instead, its value will be primarily to indoctrinate students in evolution.”

We want to see the germs evolve powered flight, sonar, and the ability to compose symphonies. Then we’ll be impressed.