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Neil A. Campbell

"It wasn't really a matter of seeking out a museum A lthough many working scientists are affiliatedwith a univer- environment or museum career. I came up under a sity or college, some conduct their researchin unusual settings. Niles Eldredgeis a paleontologistat the AmericanMuseum of Nat- programthat we still have-part American Museum ural History in New York City where he is the curatorof the In- of NaturalHistory, part ColumbiaUniversity. At that vertebrateCollection. For more than 20 years, Eldredgehas con- time the museum curators were simultaneously full ducted research, maintainedthe integrityof the collectionand in- teractedwith the museum's many visitors. faculty members as opposed to being adjuncts the Eldredge, a general session speaker at NABT's 1990 national way we are now. So it was natural for me to join the convention in Houston, is perhapsbest known for his work on the faculty at Columbiaat the same time that I joined the controversialtheory, punctuatedequilibrium. In addition to his researchand responsibilitiesat the museum, museum. Of course, there are certain aspects of uni- Eldredge has authored nine books on evolutionary theory for a versity life that you don't have here: the extensive general audience. teaching, for instance. Here you teach if and when you want. From the point of view of scientific re- Dr. Eldredge, could you tell us about your own edu- search, the great part about this museum is that it is cation and how your interest in science and paleon- first and foremost a research institute. Many people tology developed? have left university environments to come here be- "My interest in natural history and dinosaurs was cause of the emphasis on research." just about like that of most kids who grew up in the 1950s. A really important thing happened to me Are there other advantages to a museum appoint- when I went to college at in ment besides the extra time you have for research? New York City. I took a course in my "It gives you the opportunity for closer contact with junior year, and I became very deeply involved with the public through exhibitions and educational pro- it. I think I had decided to become an academic al- grams. For example, I like to go on the museum's most before I picked a field, and then I got swept educational cruises and hang over the ship's rail and away with circumstance and found a field very have a beer with people and talk about , evolu- quickly for which I developed a real, intense love- tion and so on, and admit that I don't always know invertebrate fossils. There are literally trillions of all the answers." them out there, so it looked like a wonderful oppor- tunity." This interview is the last in a series excerpted from con- versations between eminent biologists and Neil A. Camp- bell, author of the textbook (Benjamin/Cummings And now you're a curatorin the Department of In- Publishing Co., Redwood City, CA). The interviews are from the second edition of Biology. vertebrateshere at the American Museum of Natural Campbellhas taught general biology at CornellUniversity, History in New York. Most academics opt for uni- Pomona College and San BemardinoValley College. He is versity careers. How is it that you decided on a mu- now at the University of California,Riverside. seum?

264 THE AMERICANBIOLOGY TEACHER, VOLUME 52, NO. 5, MAY1990 What does it actually mean to be curatorof inverte- public, in 1982, was TheMonkey Business. I got drawn brates? into that because I found myself unwittingly being "The first obligation of a curatoris original scientific used by the movement. I had given an research. Service to the museum comes next and in a interview in which I was attempting to say that I collection-based department such as ours, that thought it would be appropriatefor a high school bi- means maintaining the collections. The museum is ology teacher getting into to acknowledge really a library of natural history items. Curators that creationistbeliefs exist, that students may have have a mission to maintain these collections as a sort such religious beliefs but that they would be ex- of a public sacred trust. You have to have a commit- pected nonetheless to study what science says about ment to the importance of the work that revolves evolution. My position was misrepresented as sup- around the collections before you work in a museum. porting the teaching of creationismin high schools. I Computerizing the collections is another task. We felt embarrassed and used. I got mad and wrote a have an on-line collection inventory that people can little article for the New Republicand then later ex- call from all over the country. The scientific staff is panded it into a book. As I was doing this, I found also responsible for the veracity of the content of the out that I had to be able to explain to anybody what exhibits. There are normal administrative duties, the basics of evolution were, and that turned out to teaching at institutions in the vicinity, giving lectures not be as easy as I had thought. I also realized that a Downloaded from http://online.ucpress.edu/abt/article-pdf/52/5/264/45012/4449106.pdf by guest on 25 September 2021 and so on. And of course, field work takes us out of lot of my colleagues were in the same boat, and I the museum." thought that it was incumbent upon all of us to try to address this communicationproblem. The museum is setting up a laboratoryfor molecular When you write for the general public you can systematics. How do you think molecular biology write for intelligent people who don't share all the will influence modern evolutionary biology? special training in a field and still write things that "In several ways. Molecularbiology gives us insight are very interesting and from which readers can into things we can't see with our old technology, and learn. Another side of this is that you can take your this potential is very exciting. What is even more in- message to the intellectual world by spreading it teresting to me is to see molecular biologists who even more widely. Several times in my careerI have don't want to be just molecular biologists, but are had colleagues point to a general piece of writing and thinking, 'This has to have some evolutionaryimpli- say, 'That is the first time I have ever really under- cations.' It is quite obvious already from gene se- stood that point.' The mid-ground, as I see it, is the quencing data that there are greatersimilarities in the fact that I am always writing for students." sequences between organisms that share a relatively recent common ancestor. And comparisons of DNA There has been a revival of interest in paleontology can be used to assess more distant relationships.The in the past 10 years or so. How do you account for reason I am particularly interested in seeing this this? work done in our department is that invertebrates "That is an intriguing question, and I don't have a were already differentiated into the major phyla pat answer. Traditionally,paleontologists have been about 600 million years ago. I am hoping that the content to describe the contents, the furniture,of the data for highly conserved sequences of DNA will world and have not been too concerned about cause. help us analyze the evolutionary relationships be- They write about what has happened and pay less tween the major groups of invertebrates." attention to how or why it happened. In the 70s they started talking about causal relationshipsrather than Are there opportunities for undergraduatesor new simply describingfossils. In addition, they didn't just graduates to intern in natural history museums? take a body of biological theory on faith and use it to "We have had a graduate/undergraduate research explain the data; they looked at the fossil data program;I started here in that program. It is not re- and asked, 'What does this tell us about the theory?' stricted to summer, though it is used mostly during This made paleontology more exciting. By the late the summer. In addition, the museum is now giving 70s there were rumblings from the paleontological pre-doctoralfellowships. It is incumbent upon us to community about the nature of the evolutionarypro- train our successors. We have to become even more cess, and biologists and geneticists were beginning to dedicated to an educational approach than we have take notice. At the same time, creationism was re- been." surfacing, and the creationistswere quoting the new theory called "."We "Punc Dr. Eldredge, you have written several books for Eeeks"-, Steven Stanley, myself non-scientists. What moves you to write for the gen- and a number of other people-seemed to give aid eral audience? and succor to the enemy by daring to criticize the "One of the first books that I wrote for the general Darwinian message, when in fact we were turning

ELDREDGE 265 out to be some of the more vocal, more visible anti- of species changed. If it is not possible to relocateto a creationists. So that brought paleontologists back tolerable environment, then is the next into view. And then there is the phenomenon of Ste- most likely thing. The least likely thing is for a phen Jay Gould himself, an exceptionally popular species to become modified in the face of a changing writer for the general audience. More than any other habitat. I think that evolution does basically repre- person he probablysymbolizes the revival of paleon- sent a match between organisms and environment. I tology in the minds of people." just think that it is a tremendously conservative pro- cess most of the time." You mentioned punctuated equilibrium. Can you describe the theory? "There are really two components to the basic Then how do new species originate? theory, neither one of which was terribly original. "I agree with ErnstMayr and others that speciationis First is how we interpret the fundamental observa- first and foremost the establishment of a new repro- tion that there are few good examples of slow, ductive community from an old one. If a small popu- steady, gradual transformationwithin species in the lation is split off from a larger parental species at the fossil record through time. Darwin attributed this periphery of the species range, you are probably lack of evidence for gradual transformation to the looking at organisms that are adapted to the ex- Downloaded from http://online.ucpress.edu/abt/article-pdf/52/5/264/45012/4449106.pdf by guest on 25 September 2021 fact that paleontology was a very young science in tremes of environmental conditions that the species his time and the fossil record was incomplete. But a can tolerate. Populations living out there at the hundred years later there still weren't many satis- margins of the species' range are already adapted to fying examples of gradual transformation. The some extent to a different kind of environment. If theory of punctuated equilibriumtakes this observa- that population ever becomes completely isolated tion at face value and accounts for the rarity of and can no longer interbreedwith other populations, gradual transformationby emphasizing stability in adaptationto the local environmentcan be solidified. the history of each species. The morphology of a By setting up reproductive isolation, what you are species changes little after that species becomes es- really doing is giving a chance to a fledgling popula- tablished. tion to have its own history and it is not going to be Secondly, this implies that most anatomicalchange sharing genes any more with the parentalspecies-it is compressed into the relatively short time it takes is sink or swim time. Most probably sink and suffer for to occur. Of course, the changes aren't early extinction. But if an isolated population sur- sudden from a genetics point of view; we are talking vives and establishes a new species, most anatomical about 5 to 50,000 years, ample time for the kinds of change probablyoccurs relativelyrapidly." changes we are talking about. But it is sudden vis-a- vis the typical long histories in the fossil record Is there evidence for punctuated equilibrium in where individual species hardly change at all. So human evolution? most anatomicalchange in the fossil record seems to "Humans are really tricky. It is easier to see punctua- be concentratedin relativelybrief bursts punctuating tion in lineages with a lot of adaptive anatomicalspe- longer periods of relative stability." cialization:they tend to be rather short-lived in the fossil record, and typically they show a lot of specia- Doesn't this idea that stability prevails in the his- tion. Hominids are a funny mixture, adaptively tory of a species challenge conventional Darwinism? speaking. We are very specialized because of our cul- "Darwin argued that evolution was an inevitability, ture, and our big brains are obvious anatomicalfea- and he was basically right. But among many of tures that are tied in with our cultural . Darwin's followers the feeling grew that since the en- On the other hand, we are generalists in how we vironment is always changing, it follows that evolu- cope with environments; in fact, our cultural suc- tion within species occurs continuously-that no cesses sort of enhance our ecological generalness. So species is going to remain the same. People are now the fossil record on hominids is very funny. Some beginning to see that what often happens when the anthropologistsclaim that there is statisticallyno sig- environment changes is that species track suitable nificant difference between the brain size of the ear- habitats. I mean, adaptationsdo change-there is no liest Homoerectus and the latest erectus.The picture question about that and I am sure they change, at you get is of a successful species that runs from least in part, in response to changing environments. Southern Africa all the way to Java, that was vari- But what usually happens is that organisms relocate able, particularly culturally, but that persisted for -even trees, via mechanisms that disperse seeds. about 1.5 million years without any statisticallysig- That is what happened during the Ice Ages in North nificant change in brain size. Other people don't America. There wasn't a tremendous amount of evo- agree with this interpretation.Human beings are not lutionary change going on but the geographic ranges the best case for punctuated equilibrium."

266 THE AMERICAN BIOLOGY TEACHER, VOLUME 52, NO. 5, MAY 1990 In your book Life Pulse, you wrote that if Darwin's organizations occurringwithout a fireballcoming in expectation of gradual progressive change does not from space." emerge from the fossil record, the main signal in life's history is extinction. Would you please ex- Isn't the view that mass extinction is an important plain? force in evolution at odds with some people's im- "I have the feeling now that if extinction hadn't pression of evolution as a progressive improvement chewed up the ecological fabric of life periodically, of life on earth? nothing much would have happened. You get some "I think our tendency to view evolution as progress background speciation going on, but not really any- stems from Darwin's time, when change could be ac- thing very dramatic. For example, if you look at the cepted as a real phenomenon in nature only if it was marine forms of the Paleozoic era, there are several viewed as improvement and progress. I don't know periods of time where the ecosystems are fairly well if we would call a cheetah species that is slightly established. Certain communities of species keep faster-running than the mid-Pleistocene species moving around geographicallybecause the environ- progress, but if your criterionis speed, it is improve- ment keeps changing, but pretty much the same ment. The really complex adaptations-the dis- species are forming the same sorts of communities guising body forms of walking sticks (insects) are a Downloaded from http://online.ucpress.edu/abt/article-pdf/52/5/264/45012/4449106.pdf by guest on 25 September 2021 over and over again through millions of years. Then good example-need a lot of time, a number of spe- all of a sudden the whole community disappearsand ciations to accumulate. You could construe that as a you get another community with new species. And form of progress. But extinction due to an environ- the greater the precipitatingdisaster, the greater the mental crisis has nothing to do with how well an or- difference between the old and new forms. Appar- ganism was adapted to its normal living conditions; ently, there has to be a relatively severe ecosystem it is just bad luck who goes and who doesn't go. Di- collapse before anything truly new accumulates.And nosaurs are a great example. Their extinctiondoesn't that is what evolutionary history really is like." mean that they had come to an evolutionary dead end (although dinosaurs do seem to have been on Some of these upheavals in ecosystems have appar- the decline before they finally disappeared). They ently been global. What could cause such mass ex- lived quite successfully for 150 or 175 million years, tinctions? and if they hadn't had some environmentalbad luck, "Speculation about that is rife. A lot of the older they might still be here now and, of course, we ideas about were geared toward certain wouldn't. There is nothing inevitable in the system groups of organisms, dinosaurs for instance. They that human beings would emerge. And that is where didn't take into account the fact that extinctions are the importance of extinction really is-it reshuffles ecosystem-wide. And very often marine, fresh water the deck." and terrestrial environments are affected simulta- neously. More effective theories take account of all Recently, a student asked me, "If extinctions have these things. I am well aware of the impact hy- been such an important theme in the history of life, pothesis-asteroids hitting the earth. I am prepared why is everybody so upset about endangered spe- to believe that not only do asteroids hit the earth reg- cies?" How would you answer that? ularly, but that when they do, they can potentially "I do not see evolution as something that is intrinsi- play tremendous hob with life. On the other hand, cally good. We are part of the biota that is now extinction seems to be so much a part of the rhythm threatened with extinction, and we have every of things I can't believe it always has the same extra- reason to resist. It is easy to take a dispassionateview terrestrialcause. As a general mechanism, I think we about other extinctions-the dinosaurs went; they have to look at sudden jump, or the threshold, ef- were great but they went-because we weren't here. fects that you get from a linear modification of the But we don't want someone down the road saying climate. A climaticchange, which could be as little as about us, 'They were fine in their time.' I think also a drop of 1 to 2?C in mean annual temperature, is that the biota is interconnected enough that severe going to have a tremendous effect on distributionof degradations,severe extinctionsof other species, will organisms. Some organisms will be able to adjust seriously affect human life. There is no question much better than others. It is a catastrophe only in about that. Finally, the conditions that are elimi- retrospect-these changes usually take place over nating other species are also very directlythreatening the tens of thousands if not half-a-million years. our own existence. That is perhaps even more to the People are concerned about how our own influence point. For a variety of complex reasons, our future is on the climate might affect the rest of life. We are very much going to be mirroredin the fates of other clearly worried that something major could happen, species around us. So, if we care about our own fu- particularlywith our own negative intervention. So, ture, we ought to care about the fates of other it is perfectlypossible to imagine severe ecologicalre- species."

ELDREDGE 267