Explore Evolution The Arguments for and Against Neo-Darwinism

No, We Didn’t Make Up The Controversies — A Reply to John Timmer

Does the biology textbook Explore Evolution manufacture false controversies about evolution, while ignoring real ones?

That’s what biologist and science writer John Timmer claimed in a post earlier this week at Ars Technica. Timmer attended a two-day symposium on evolution at Rockefeller University and noted the many debates brewing there. “Evolution clearly has no shortage of controversies,” he concluded . But those real controversies have “no overlap,” he claimed, with the “ostensible” (i.e., fake) controversies supposedly “manufactured” by Explore Evolution. Bottom line for Timmer: while students may, or may not, need to learn about controversies in evolution — he leans strongly towards “not” — Explore Evolution is misleading at best, and the academic freedom bills being introduced around the country aren’t needed.

Now, when he wrote his blog entry, Timmer hadn’t actually read Explore Evolution. His comments about the book were based on what he could glean from the book’s website, and from other writings by its authors.

But, as Timmer will see when his review copy of Explore Evolution arrives (one is on its way to his office in New York), the book does not manufacture the controversies it reports and many of the very debates he saw firsthand at the Rockefeller symposium were already featured in Explore Evolution’s pages.

To take one example, students who might have learned from the book about the ideas of Canadian molecular geneticist W. Ford Doolittle, concerning problems with molecular homology would have been primed to ask Doolittle questions following his Rockefeller lecture.

In other words, those students would have been well-educated. Amazing, isn’t it?

Open Any Evolutionary Biology Journal: Controversies Abound, at All Levels

First, let’s correct the record. Timmer writes that Explore Evolution “presents common descent as controversial exclusively within the animal kingdom.” That’s false: the book considers, in some detail, molecular evidence, such as ORFan sequences (i.e., genes with no known homologues) and variant genetic codes, that is used to evaluate relationships among single-celled organisms. Thus, Timmer’s claim that the controversies on display at Rockefeller have “essentially no overlap with the areas that Discovery would like to pretend are controversial” is simply wrong.

More seriously, Timmer should know that a single symposium — even one as fascinating as the Rockefeller event — does not a science make. Consider the topic of anatomical homology, central to arguments about the common ancestry of the animals.  Explore Evolution focuses on the revolution in evolutionary theory’s understanding of homology that has been brought about by discoveries in developmental biology and genetics within the past two decades. Many biologists unfamiliar with these findings still hold the standard textbook view that homologous anatomical structures are caused by homologous genes and developmental pathways.

But those textbooks need to be updated. As Gunther Wagner (2007, 473) notes,

Intuitively, one would expect that the historical continuity of morphological characters is underpinned by the continuity of the genes that govern the development of these characters. However, things are not that simple: one of the most important results of the past 15 years of molecular developmental genetics is the realization that homologous characters can have different genetic and developmental bases. This seems paradoxical, because the historical continuity of morphological characters implies continuity of the (genetic) information about the characters.

Are students likely to learn about these discoveries from their standard biology textbooks? No. Will they learn about them in Explore Evolution? Yes. 

Or consider Timmer’s discussion of what he sees as a settled climate of opinion about the efficacy of natural selection:

Explore Evolution seems to think a reply can be made to the arguments in favor of natural selection. Based on the symposium, the scientific community clearly doesn’t. Selective pressure made appearances in nearly every session.

Maybe, but that’s not because the role of natural selection in biological explanation is uncontroversial, as Timmer asserts. Big fat volumes seeking alternatives to selection — Mary Jane West-Eberhard’s massive Developmental Plasticity and Evolution (Oxford, 2003) tips the scales at 794 pages, printed in a magnifier-begging tiny font — dedicated symposia, and indeed entire research programs within evolutionary theory derive from a deep dissatisfaction from the neo-Darwinian emphasis on the centrality of natural selection.  Michael Lynch of Indiana University (2007, xiii) expresses this dissatisfaction about as bluntly as anyone could:

…it is quite remarkable that most biologists continue to interpret nearly every aspect of biodiversity as an outcome of adaptive processes. This blind acceptance of natural selection as the only force relevant to evolution has led to a lot of sloppy thinking, and is probably the primary reason why evolution is viewed as a soft science by much of society.

Timmer calls Explore Evolution’s discussion of natural selection “hallucinatory” — on the contrary, if anything, the book soft-peddles the problems. Again, will students learn about these debates from their standard texts? Almost certainly not.

The Coming Crisis for the Science Establishment

No, I don’t much like the paranoid or ominous-sounding phrase “science establishment,” but for the moment, it will have to do. (I have in mind organizations such as the National Academy of Sciences, the major professional scientific societies that regularly issue anti-ID edicts [you know who you are], and lobbying groups such as the National Center for Science Education.) There is a growing disconnect between statements issued for public consumption by “the establishment,” about the certainties of evolution, and the actual state of evolutionary theory, as one finds it in the primary research literature, at meetings (such as the one Timmer attended, and where I often find myself), and in personal conversations and communications with evolutionary biologists. I speak from long experience. As that distance — that disconnect — increases, an inevitable crisis looms.

Here’s an example.  Natural selection, as Darwin discovered, explains the origin of biological complexity, novelty, and innovation. There’s a stock phrase that populates any number of official statements about evolution. One could utter that statement in any biology classroom around the USA, and no one would blink. You know: Darwin found the process by which new structures evolved where they did not exist before.

Now here’s the opening argument from a research paper I happen to be reading this week, from the evolutionary theoretician Armin Moczek (2008):

Given its importance and pervasiveness, the processes underlying evolutionary innovation are, however, remarkably poorly understood, which leaves us at a surprising conundrum: while biologists have made great progress over the past century and a half in understanding how existing traits diversify, we have made relatively little progress in understanding how novel traits come into being in the first place.

What happens to the credibility of the science establishment — on the subject of the bona fides of standard evolutionary theory — when “Darwin already explained that, put your hand down” comes into contact with “Well, we don’t really know?”

Not letting the kids talk about it…there’s a winning strategy.


Lynch, Michael. 2007. The Origins of Genome Architecture. Sunderland, MA: Sinauer Associates.

Moczek, Armin. 2008. On the origins of novelty in development and evolution. BioEssays 30:432-47.

Wagner, Günther. 2007. The developmental genetics of homology. Nature Reviews Genetics 8:473-479.

The Arguments for and Against Neo-Darwinism