University of Rochester

Rochester Review
January-February 2009
Vol. 71, No. 3

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Q & A Why Darwin Matters As H. Allen Orr prepares to receive one of the rarest accolades in science, the prominent evolutionary biologist talks about the theory of natural selection, its public perception, and the legacy of Charles Darwin. Interview by Scott Hauser
photo of OrrDARWIN’S LEGACY: “Whether you’re doing molecular work, genetic work, paleontological work, or even some ecological kinds of work, Darwin looms large,” says H. Allen Orr, who will receive a Darwin-Wallace Medal in February for his work as an evolutionary biologist. The medals have been presented only once every 50 years since 1908.

H. Allen Orr likes to point out that he came to the study of biology relatively late in his undergraduate life. A philosophy major at the College of William and Mary, Orr didn’t turn seriously to biology until his junior year.

But once the field had his attention, Orr, a University Professor and the Shirley Cox Kearns Professor of Biology, approached it with an intellectual rigor that has combined not only a knack for what he calls exploring the “neglected questions” of the field but also a scientific rigor that relies on statistics, molecular biology, and old-fashioned genetics. His work in the field of speciation, the process by which one species evolves into two separate species, has garnered him an international reputation.

At the same time, he has continued to exercise his philosophical muscles, writing book reviews and essays about issues in evolutionary biology for such publications as The New Yorker, the New York Review of Books, the Boston Review, and others. A champion for a nuanced understanding of evolution, Orr has been willing to take on opponents of natural selection as well as to argue with fellow evolutionary biologists about the field and its implications for education, religion, and culture.

On Feb. 12, the 200th anniversary of the birth of Charles Darwin, Orr will be one of only 13 scientists from around the world to receive a 2008 Darwin-Wallace Medal from the Linnean Society in London. Awarded only once every 50 years, the medals mark the 1858 original reading of the papers by Darwin and by Alfred Russel Wallace that introduced the theory of natural selection.

In an edited interview, Orr discusses evolution, its public perception, and the ideas that Darwin put in motion 150 years ago.

Scientists have been working with the theory of natural selection for 150 years, yet to judge some public perceptions, evolution is still up for debate. Why has it been such a hard sell, so to speak?

The short answer is that scientists engage in a larger debate about what evolution is because creationists keep coming up with new forms of creationism. Every couple decades, it seems, a new kind of opposition flares up. In the time of Darwin, there were literal creationists; there was the Scopes trial in the early 20th century; in the 1970s, we had a wave of scientific creationists. And in the last 10 years or so, we’ve had another wave, known as intelligent design creationism. As somebody has quipped, “Nothing evolves like creationism.” It constantly goes through these cycles where a new species emerges and then scientists have to battle a new version. And the latest version of intelligent design has been very visible on the cultural landscape.

Joining a ‘Remarkable Group’

When H. Allen Orr receives the Darwin-Wallace Medal on Feb. 12, the 200th anniversary of Darwin’s birth, the Rochester professor will be joining some heady company in the history of evolutionary biology.

One of only 13 people in the world selected to receive the highest honor presented by the Linnean Society, the world’s oldest active biological society, Orr will take his place not only among such 2008 recipients as the late Stephen Jay Gould and John Maynard Smith (both of whom are being honored posthumously), but also among such giants in the field as J. B. S. Haldane, Ernst Mayr, R. A. Fisher, Ernst Haeckel, and Alfred Russel Wallace, who was presented with one of the first medals in 1908.

Awarded only once every 50 years to mark the anniversary of the 1858 reading of the Darwin and Wallace papers that outlined the theory of natural selection, the medals are one of the rarest awards given in science.

Orr, who presented a paper to the society in London last July to mark the 150th anniversary of the reading of the original papers, says he was surprised and humbled by his selection.

“It’s more humbling than exciting, it’s fair to say,” he says. “These are the people you grow up studying closely. You’re not sure you really belong on that list. It’s a pretty remarkable group of people.”

—Scott Hauser

Is this particular to evolution? Do other natural sciences fight these battles?

We are certainly the most common target, but I don’t think we are the only target. There is some movement against big bang cosmology and against modern physics. But I think that always takes the back burner. The front burner is always evolution. I think the theory is perceived as more vulnerable because it’s seen as less palatable to the public.

Why is that?

I think it’s because evolution hits us where we live, which is, it’s us. It’s not a theory about what some particles did in the first few seconds of the universe. It’s a question of our own physical origins, so it just strikes closer to home. I don’t think that the creationist movement wants to end by attacking evolution. I think it’s clear that in some quarters of the movement, proponents of intelligent design want to attack cosmology and some brands of social science.

Where do things stand now? Did the 2005 court case in Dover, Pa., settle the debate?

It’s not over, but I think the debate is much quieter than it was. I think Judge Jones’s ruling in the Dover decision [Tammy Kitzmiller, et al. v. Dover Area School District, et al.,] was very strong and very firm. I think he has made it fairly difficult for intelligent design to try to intrude itself into the science classroom in public schools. His ruling there was remarkably clear and firm. So I think that it’s not over but it’s quieted down some.

Does the public perception of evolution in the United States imply a lack of scientific literacy?

It’s a funny situation because the popularity of intelligent design creationism—or any brand of creationism—does suggest that we evolutionary biologists have a problem communicating with the public. But evolutionary biology has been blessed with some of the most gifted science popularizers ever. We are the field that has Stephen Jay Gould, Richard Dawkins, and a host of really talented writers who have introduced evolutionary biology to the public. So something is not connecting. Part of the problem may be that the public schools in America are paying minimal attention to evolutionary biology because it is a sensitive topic. My guess is—I don’t know this—but my guess is that a lot of public schools say as little about it as they can get away with and the result of that is a fairly uninformed populace. I don’t think Gould and Dawkins can make up for that. The other thing that’s going on is that the popularity of the attacks on evolution partly results in evolution being seen as anti-religion. The intelligent design community, in particular, has played up the allegedly anti-religious overtones of evolutionary biology. They present it to the public as though they have a choice—you either have to subscribe to the theory of evolution, or you can be religious. I personally think that’s disingenuous.

But Dawkins, in his books like The God Delusion, clearly argues for the anti-religious overtones.

That’s true. It’s a complicated situation. Within evolutionary biology, you find all kinds of attitudes. Dawkins is at one extreme. Dawkins does seem to think that reason requires both belief in evolution and atheism. There are other prominent evolutionary biologists, like Stephen Jay Gould, who argue that science and religion are in some ways compatible as long as you recognize that science is doing its kind of business and religion is doing its kind of business. Clearly the intelligent design community has played up the Dawkins version. But it’s important to make the point that I don’t think evolution represents a conflict between science and religion in general. It represents a conflict between science and a particular kind of religion done in a particular place and time. It’s important to realize that the creationist movement is largely an American phenomenon. There are plenty of religions around the world that don’t have any trouble with the theory of evolution. And there are lots of religious organizations—the Roman Catholic Church, for example—that don’t see a conflict between science and religion in general. If there is a conflict, it’s between science and certain denominations or certain sects of religion.

Where do you stand in those debates?

I don’t know where I stand personally on religion. I reviewed Gould’s book where he made his argument and at the time I didn’t find his arguments very convincing. But there might well be some ways to reconcile science and religion. But that’s not how the intelligent design community wants it presented. The intelligent design community wants it presented as a very fundamental conflict between science and religion and you have to choose one or the other. Regardless of where I stand, the history and sociology of the problem says that’s not true. There are plenty of religious people who subscribe to the theory of evolution. I don’t think it should depend on what any one particular person says or thinks—whether me or Stephen Jay Gould or anyone else—it’s just a historical and sociological fact that the conflict is not as simple as the intelligent design community wants people to believe.

What do you think Darwin would make of the debate about natural selection 150 years later?

I’m not a Darwin scholar, but clearly he was anxious about how the theory of evolution was going to be received. I don’t think he was surprised that there was animosity toward the theory at the time that he introduced it. But I think he’d surely be shocked that 150 years later this kind of animosity still exists and that the theory of evolution is being attacked in court.

Was he a vocal champion for natural selection?

Darwin’s own style was very low key. By and large, he did not engage in public debates about the theory of evolution. He did his research, he wrote his books, and when it came to the public, he let others step in and do that work. He was a reclusive man, a very reserved guy, and he was not suited for those sorts of public debates. He had others—T. H. Huxley, famously known as “Darwin’s bulldog”—and a circle of friends who did the public defense of evolution. As far as I know, Darwin didn’t do any of that. He wrote letters. But I don’t think he ever publicly debated anyone over the theory of evolution.

What about you? In your book reviews, essays, and some public engagements, you’ve been willing to enter the debate.

I have mixed feelings about it, actually. On the one hand, I think that evolutionary biologists have an obligation to do some of this, and respond to these challenges. On the other hand, I can’t claim that it’s all particularly fun. It would be better if we did not have to do this. I enjoy doing book reviews, but I don’t particularly enjoy the public things. Most evolutionary biologists I talk to feel that way—the ones engaged in this—feel some sort of moral or professional obligation to do some of this, but you have to draw the line or else everything else you’re trying to do—scientifically and intellectually—gets lost. I’ve really worked hard to keep some balance. I’ll write some book reviews and think hard about these issues, but not let it dominate my professional life.

If you could clear up a misconception about evolution, what would it be?

I think the most common misunderstanding is that it’s a goal-oriented process. That it’s a process by which organisms like humans get progressively “better.” Gould famously argued that evolutionary history is full of all kinds of historical contingencies. His metaphor was that if you played the tape of life again you’d probably get a very different outcome. I’m sure he’s right on the details. I’m sure that if you played the tape of life again you would not get human beings that look exactly like human beings as we know them. That would be pretty remarkable because there are all sorts of historical contingencies—which mutations pop up when, for example, or which environmental phenomena like asteroidal impacts happen when—influence life. But I think Gould probably went too far in his consideration of how contingent evolution is. While evolution is not progressive in the usual sense, I think there are certain features of organisms that would probably repeatedly evolve. We know that some things do repeatedly evolve, like eyes. Vision has evolved over and over again so that’s clearly a good thing to have. The evolution of diploidy, the fact that we carry two sets of chromosomes, has clear advantages. I’d be shocked if that didn’t happen again. The evolution of sex itself, of recombination, is another. I suspect, and this is just a hunch, that the evolution of intelligence is another one. There’s such a strong evolutionary advantage to intelligence that, given enough time, it’s going to happen again. That doesn’t mean you’re going to get to human beings. An analogy would be thinking about what might happen on another planet. I think most of us probably think there’s life on other planets, and we would not be surprised to learn there’s intelligent life on other planets, but we would be surprised to learn they look just like people.

You have said that speciation had been neglected in the middle to the latter part of the 20th century, and that’s why you started focusing on it. Is it still neglected?

The simplest way to think about evolutionary biology is that it’s about two processes. One is how a single evolutionary lineage changes through time under various evolutionary forces, like our own natural selection. And the other is how single, evolutionary lineages split into two lineages—the origin of species. While I have been doing work in both processes, speciation is where I’ve been focusing. Evolutionary biology historically has focused on the first process, of how a single evolutionary organism changes. And the problem of how a single organism splits into two lineages did sort of get neglected historically. So that’s been a big deal over the last 15 or 20 years or so, and I’ve been part of that, and so have a number of other labs. But we also do a lot of work on evolutionary change within single lineages. A lot of that work is theoretical. It’s theoretical population change. It’s mathematical stuff.

Why was speciation neglected?

There’s a really complicated history. The funny thing is that in the 1930s, during the so-called “modern synthesis,” when evolutionary biology sort of all came together, there was a period in the 1930s when Darwinism became neo-Darwinism and it solidified as a coherent body of thought. The geneticists and the naturalists and the mathematicians and paleontologists all arrived at a fairly common view of how evolution proceeds. During that period, speciation was a big deal. The book that most people think of as launching the modern synthesis was Theodosius Dobzhansky’s book in 1937, called Genetics and the Origin of Species; it was about speciation. But sometime in the 1940s, the field by and large shifted to thinking not about speciation, not about splitting lineages, but about evolution as change within a lineage. And that remained true for most evolutionary biology until about the 1980s. And I don’t fully understand the reasons why that happened. I think some of it was force of personality. There were some very visible leaders in the field, including Dobzhansky, whose interests changed. Dobzhansky’s own work shifted from the origin of species, and a lot of people followed. I think that’s part of the story. But also all kinds of new data became available. And then the molecular revolution happened. So there was a lot of population genetic analysis to be done—at the protein level and at the DNA sequence level, all within species. New technology opened up new questions about evolutionary changes within a lineage. And it took awhile before people started applying the same techniques and ideas to splitting lineages.

How has the molecular biology revolution influenced the work of evolutionary biologists?

Genomics has not been an intellectual revolution. But it has been an incredibly important and powerful tool. And that tool has been used both by people who study changes within lineages and probably even more by people who study the splitting of lineages. Just about every population geneticist interested in evolution is using some sort of genomic aid, at least as a tool. It’s an enormously powerful tool that you can just go online and click and see, there are the genes, and here’s what it looks like in this species and here’s what it looks like in that species. It’s pretty remarkable.

What does an evolutionary biologist do with that?

We’re at a stage now where the field has flip-flopped. I think it’s fair to say that 20 years ago we had lots of theorizing about population genetic processes and not much data on some of those processes. We had more theory than we had data. Now it’s turned around. Now we are swimming in a sea of data. And probably the population genetic theory has not quite caught up. I think that what’s mostly going on now is people are trying to take that huge amount of data and figure out ways to infer from it what were evolutionarily important forces. Did this change by virtue of natural selection? Or did this change by virtue of some random force, like genetic drift? It’s an exercise in taking that ton of data and inferring from it the relative role of various theories. To what extent was mutation important to accomplish that change? How about genetic drift? And so on. There’s a big exercise now in statistical inference. To the extent that I understand this, we’re sort of in the same position as astronomers. It’s my understanding that astronomers also have vast reams of data and it’s all an exercise in trying to figure out what you can and cannot legitimately infer from that data. Evolutionary biologists are in the same position. We have tons and tons of data that didn’t exist 20 years ago. Most of it didn’t exist 10 years ago.

It’s amazing to think that Darwin did all his inferring from one very long trip aboard the Beagle.

There are similarities. Darwin lived in the age of discovery. People were going out on those voyages and sending all these bizarre organisms back to London or back to Paris. In a way, what is going on now is similar. We suddenly have this age of data-rich discovery. Data are just pouring in. I think it’s fair to say that we haven’t had a Darwin yet. Nobody has taken that new data and said, “Oh, boy, here’s the big surprise.” And maybe we won’t. But certainly as a tool, it’s just been amazing.

Will there be another Darwin?

I think the one thing that the history of science teaches you is that predictions about the future of science are very dangerous. The world is full of surprises. It’s certainly fair to say that we now all—evolutionary biologists—we all live in Darwin’s shadow. Darwin still looms very, very large. No one has come close to that sort of stature. There are a few narrow specialties, like molecular biology and the molecular revolution, so there may be figures and schools in the molecular revolution, but I don’t think there has been anyone like Darwin who hangs over all those fields. Whether you’re doing molecular work, genetic work, paleontological work, or even some ecological kinds of work, Darwin looms large. We have people within those specialties, but we don’t have anyone that covers all of them. Will that happen again? It’s hard to picture, but the history of science is full of surprises.

Scott Hauser is editor of Rochester Review.