Kevin Boyce

Charles Kevin Boyce

Professor of Earth and Planetary Sciences, Stanford University

By David Zierler, Director of the Caltech Heritage Project

March 15, 2024

ZIERLER: This is David Zierler, Director of the Caltech Heritage Project. It's Friday, March 15th, 2024. It's my great pleasure to be here with Professor Kevin Boyce. Kevin, it's great to be with you. Thank you for joining me today.

CHARLES KEVIN BOYCE: Thank you. I really appreciate the opportunity.

ZIERLER: Kevin, to start, would you please tell me your title and affiliations at Stanford?

BOYCE: I am a paleontologist. I am a Professor of Earth and Planetary Sciences at Stanford University.

ZIERLER: Now, the term "paleontologist," is that inclusive of paleobotany? Are those adjacent fields? How does that work?

BOYCE: Paleontology is a larger umbrella term, but paleobotany is the plant end of paleontology.

ZIERLER: Is that to say that there's things that you do in paleontology that are not plant-related?

BOYCE: Yes. I started with the plants, but have expanded from there.

ZIERLER: Let's talk about flora and fauna. On the fauna side, on the paleo side, because I know temporally this will be significant and then thematically as well, so in paleontology, not plants, what do you focus on?

BOYCE: I started out with plants, and they present opportunities that I have appreciated. But I'm not, I've never been a plant person or really into dinosaurs or really into gardening. I've never been a partisan enthusiast like that. It's just plants were a very useful starting point as things that bothered me in a lot of ways as far as how they grow and move around water and stuff like that, that you could also work with in the fossil record. More recently, that's still very much a part of it, but I've grown to try to encompass more of the entire terrestrial ecosystem, and the fungi, and the little things down in the soil, and invertebrates, and all that kind of stuff, and just think about the whole system, and how the whole system has changed. The plants are very much a part of that. They're all the biomass still, but it's also more inclusive.

ZIERLER: When in your career did you expand beyond plants? When does that happen?

BOYCE: It's always been there a little bit. Even back as a postdoc, I worked on some fossil fungi or maybe-fungi back then. The fungi were there, and had been there for a while in my work. Then it's really since moving to Stanford that I really tried to embrace all of it. I taught a class—I was at the University of Chicago for 10 years before Stanford. When I was there, I was surrounded by a lot more paleontologists and a lot more diversity of it. I could teach classes on the evolution of terrestrial ecosystems, and do it with a dinosaur guy as my co-teacher. It was really moving away from that, coming to Stanford, that suddenly I didn't have that, and so I had to think more about how do I want to encompass all of diversity of material myself, and not just rely on the crutch of the co-teacher, and really think more broadly about the system. Then it ends up influencing your science and everything else. Teaching is always about what you want to do scientifically, and not so much about the teaching aspect of it.

ZIERLER: The ancient eras before recorded history, what eras or eons are you looking at?

BOYCE: I mostly work in the Paleozoic, which is 540 million years ago to 250 million years ago or so. Within that, I start mostly in the Silurian or the Devonian, so around 420 million years ago, because that's when land plants and the fossil record of terrestrial life begins is around then. Then I carry it forward to the present. On some level, if you want to understand what's going on in deep time, you have to think about the present. It's important in particular for different ends of this, because for plants, the plants that dominate the modern world are a very specific group, flowering plants that have not been around that long. You have to think about them, and how they're different from what was around 400 million years ago. You have to span time. But it's mostly the last 420–450 million years or so.

ZIERLER: Are you interested or is your research relevant to foundational questions on origins of life or at least origins of complex life?

BOYCE: Complex life, if defined as multicellular, that's earlier, and the origins of life is obviously [laugh] quite a bit earlier. The multicellular groups of plants, animals, fungi, plus a variety of algae, that's largely occurring earlier, going back to about a billion years. The fungi are very tied to land, and that's an important group of multicellular life. Within the green algae, the land plants is one lineage, but they're still green algae, and green algae were already multicellular. There's a question of complexity. There's a lot more complexity to later multicellular organisms, such as land plants versus most algae, so there is something of a progression there. And before that, there would've been life on land going back billions of years, but it would be simple microbial stuff.

ZIERLER: What do we know about what was happening on the planet that compels you to start your study 540 million years ago? What were the developments then?

BOYCE: There are almost aesthetic answers to that. I like fossils [laugh], and I like fossils that you can see, and pick up, and they're heavy, and you can look at them. You go back into the Precambrian, before 540 million years ago, and those characteristics aren't there to the same extent. I was in a lab that was largely Precambrian for graduate school. My advisor works in the Precambrian. But I like the fossils that you can pick up and look at and think about. I like multicellularity because I like the complexity of thinking about how things grow. Even if you can't provide a modern molecular developmental type context, you can still think about how they could grow, and how they would've interacted with their environment. I like big multicellular things in that way. So, it is partially scientific, but I think it's partially almost just that I like the things as objects to think about. That quality isn't there for the first three billion years. You have to be closer to the present to actually get that kind of aspect of it all.

ZIERLER: Kevin, I wonder if you can explain how you use evolution as an intellectual framework, thinking about developments hundreds of millions of years ago. What does that look like, and how did that compare to thinking about evolution over a shorter timescale, tens of thousands of years, or even in the hypermodern era where we think about CRISPR and directed evolution?

BOYCE: I don't go to that short timescale. In a geological context, there are things to worry about on 10,000-, 100,000-year timescales. But those are weird perturbations to the system. When you're thinking about the longer sweep of things, you're talking about millions to tens of millions of years. There's a lot that changes, as far as perspective and the details of what matters, when longer timescales are considered. Even something like envisioning the carbon cycle, you could draw the little graphs that everybody knows from junior high. That is the short-term or ecological carbon cycle, but the carbon cycle looks completely different if you think about it in a geological context. Suddenly volcanoes matter and tractors don't, a lot of the biology falls away. There's a lot of short-term fluctuations that go on in the world in this kind of hamster wheel [laugh] that just goes in a circle very quickly, but then there's much longer patterns to be seen. That's true for the Earth and elemental cycling. There's fast cycling, and then there's longer-term changes. It's true for life too, where there's lots of things that get done with population genetics and Drosophila in worrying about the near term, you know, like for our ancestry in the last couple thousand years. But a lot of that, first, it is invisible on a longer timescale, and you couldn't study it even if you wanted to, and, second, other processes take over anyway and are more important on those longer timescales. It's more on those longer timescales that I operate. I very rarely worry about the most recent 20 million years, 30 million. I don't tend to be thinking about those more recent ends of the record.

ZIERLER: Kevin, what is the connection of your research in the global carbon cycle to what's happening today and our use of ancient fossil fuels?

BOYCE: It's really fun and weird to think about. Well, it's not fun. [laugh] It's not fun, but it is interesting to think about. There have been various points in Earth history where there's big perturbations to the system: a meteorite impact, flood basalts cover Siberia, or something like that. They're quick, they deeply mess up the system, and then the system relaxes back towards where it was at before, although some things are now gone with extinction. Those types of perturbations, they have to resolve themselves quickly. The residence time of carbon in the surface system is like 150,000 years. You do something crazy like dump a whole bunch of carbon into the atmosphere—we're doing it now, but it has happened at times in the past—it goes up there, it stays up there for 50,000–100,000 years, which is a long time from our perspective obviously, but it's not a long time geologically, and then it will go away. That's how long these processes take. What that means for the modern world, and what we're doing now, it's almost a question of perspective, which I think is useful. There's people that worry about tools and sustainability applications. What are we going to do with the carbon? But there's also just a question of perspective that has value. I think that there's a general tendency to think, well, this is the way things are, when of course it's not. [laugh] This may be the way things are, but it has been that way for 100 years, tops, 150 years. Also, part of that perspective is just the need to recognize that it will stop; it's not a virtue for us to stop. It has to stop because we are a perturbation, and perturbations don't last that long. But if you want to last longer than that, you better figure out a way to not be just a perturbation. The fossil fuels we use on a yearly basis are like a million years' worth of accumulation. You can't do that for very long. It has to stop. It's a question of, do you stop it voluntarily so that you have some control over how it stops, or do you just let it stop you, which is presumably not what we want. There's a lot of value in thinking about the long-term versus the short-term cycles because, ultimately, as a species, we would like to intersect those longer-term timescales, and not just be this little blip that lasts a little while, and then ends it itself in that way.

ZIERLER: Kevin, what is the interplay of theory and observation and experimentation in your world? What does that look like?

BOYCE: For me, I really like the physical aspects of it all. I've never been a grand theorist. I've had professors that are grand theorists. And you have to read the literature. But, for me, what I like is thinking about how did this physical thing grow? How did it move around water? If you're a plant, a plant's biology is all about moving around water. How did it move the water through that series of pipes that is a plant? Then what does that then say about the physiology of that organism, and how much photosynthesis it could have done? I like the physical aspects of, how did it get there? What's it doing? How do you make sense of it all…, because fossils can be really weird-looking. [laugh] It becomes this fun puzzle of, OK, so that's what that thing looked like. How did it grow? How did it work? Then what does that tell you about the world that it occupied? That end of it is the part that I enjoy the most.

ZIERLER: Are you deeply engaged in field research?

BOYCE: I am not deeply engaged in field work. I work a lot with fossils, but the way I work with fossils, tends to be a step removed from the field. I've done a fair amount of the chemistry of fossils, what is preserved in the fossils. I do more surveys of diversity of form through time, and what that says about how development changed through time, and how physiology has changed through time. For the chemistry end of that, you want the best-preserved example of the fossil. That's not going to be, "I'm going to go out in the field and find the best example of it"; it's going to be, "I'm going to go to the Smithsonian, and open a drawer, and pull out that best example, and use that."

I've always been more based in museums, and then honestly, on some level, based in the literature, which becomes more central when thinking about the sweep of how things have changed through time. I work a lot with leaves. It feels terrible to say but, on some level, a photograph of a leaf fossil can be more useful than the leaf fossil itself, because someone's already bothered to light it correctly and take that image. If you want to look at every fossil leaf species through time, that would be a lot of opening and closing drawers and carting samples over to the microscope and back, and at many different institutions. So, to the extent that a lot of it becomes surveying of form through time, that becomes library-based.

So, for most of my research, it's much more museum and literature-based. But, particularly in recent years, there have been some projects that have been field-based, and it's been very fun and empowering to [laugh] do that end of it as well. They're baby steps. I'm never going to be that guy.

ZIERLER: When you are a user of someone else's fossil find, for the field in general, what is valuable for other scholars, other scientists going out and finding it, and how do you make use of that larger narrative of the discovery, the preservation, the archiving? How do you fit into that overall archival process?

BOYCE: People have been collecting fossils for hundreds of years at this point, with some level of curation, not just as oddities, but with some level of care and curation in museums. The good museums have been around for centuries at this point, so there is a history that you can tap into. There are important questions that have to be asked today with field work, where you can't ask the question without collecting new specimens. People get better about understanding, statistically, about the proper way to ask particular questions, with data that follows a particular correct protocol of specimen collection, so that you must go to the field, and newly collect it in the correct way. For example, museums tend to end up with the prettiest or biggest fossils, but sometimes you need to know what the diversity would look like if you looked at every single fossil that came out of a dig, including the ones that would normally get left behind, or you needed to know that you looked at the same amount of rock surface area at each horizon you sampled. So, there's lots of field work that has to be newly done in that sense. Also, the Earth is big. There's still lots of discovery science just to be done of, "If we went to the Precambrian of Burkina Faso, what would we find there?". All of that's very much a part of paleontology and both of those end members of field research are vital.

But I've more always been interested in almost the historical aspects, both Earth history but also the historical aspect of the discipline itself. That means existing historical collections, but also historical questions. There's lots of just classical "why is the sky blue?" type questions that people asked 100 years ago, and couldn't answer. We actually have tools now, and we can ask those questions, these old questions, where people forget that those questions are out there—or think that they're old fashioned and that we have moved on from that, away from almost Victorian questions in some cases. But we can answer them now. They're fundamental interesting things. Where do leaves come from? These basic aspects of it all are really fun to think about.

ZIERLER: Kevin, a question about technology and analytical tools. As you mentioned, we've been collecting fossils for hundreds of years. There are now capabilities that didn't exist hundreds of years ago. Whether it's you looking at a photograph or an actual fossil itself, what technology can you draw on to make much more targeted assessments of what we're looking at?

BOYCE: I've done a fair amount of geochemistry, and there's various isotopic and organic-based techniques. I've done a lot of synchrotron work. I haven't done it recently, because my kids were of an age where going to a synchrotron for two weeks was really not a practical thing.

ZIERLER: [laugh]

BOYCE: I moved away from it. It might come, hopefully, will come back in the near future. A lot of the rest of my research is not necessarily different from how anyone could've done it 50 years ago or whatever. It's a difference of perspective. Honestly, the single most useful technological advance is the fact that we actually have good evolutionary trees now, phylogenies. Understanding how things are related to each other makes a big difference. It puts enormous constraints on the types of solutions you can come up with. Just the fact that the phylogenies are now pretty robust in a lot of cases, of understanding how groups are related to each other, that makes a huge difference.

ZIERLER: A synchrotron makes me think of physics. Isotope makes me think of chemistry. Of course, plants and animals makes me think of biology. The question is, when are you collaborating with subject matter experts in those fields, and when are you your own physicist or chemist or biologist?

BOYCE: Never. [laugh] You see people that try to do that, and they try to be the guy, "Look how smart I am. I'm going to go do it all by myself." They do terribly. [laugh]

ZIERLER: [laugh]

BOYCE: There are fields where I have interacted with people for decades, at this point. So, I've developed more of an intuition to how to think it through myself. But, no, I do not go to a synchrotron and say [laugh], "Take a break. I'll handle it." You always want to work with the correct people, because you want the right answer. It's not about looking smart. I would rather look dumb to someone who does know the field, and ask all the dumb questions, and make sure the dumb questions get answered. On the back end of that, you then also have to make sure that you understand everything that happened, and make sure that you know why this is the result that came out of it. But you always want collaborators when bridging disciplines. You don't want to just be reinventing the field every time you wander into something new.

ZIERLER: With all of your collaborations in Stanford, is it somewhat of an in-house effort? Can you do all of those collaborations across campus?

BOYCE: No. There's always new connections that you make and then, if they're good connections, you try to keep them. I work with people where we were postdocs at the same time, a fair amount. Then when I was in Chicago, I was in the geology department there too, but it's a much more modeling-focused department. That was an opportunity to work with climate modelers. Since coming to Stanford, there are more people that are invested in rocks than was present at Chicago. Here I've worked more with people in the geochemistry and the carbon cycle and rock record end of things. For plant physiology, that was my postdoc and a little bit of my thesis, I still work with those same people. It almost becomes an act of curation of, "OK, I now know that I think you're good, and I like working with you, and I would like to keep working with you." Then fields get added as you go.

ZIERLER: Kevin, you mentioned modeling, but also you emphasize that your love is in the physicality of the specimens. Are you a user or do you contribute to computer simulations or digital databases that enhance the field?

BOYCE: Yes and no. I don't do modeling myself. I tend to like questions where I can think it through. I like big patterns, and there's a lot of big patterns in this world that have not been recognized. There's a lot of work in this world where you need those five significant figures to glean from the statistics what's going on. I lose interest with that level of needed precision; you can't just see it. I like the fact that there are big obvious things that go unnoticed until you connect two fields, and then if you do, the patterns emerge. That's a convoluted way of saying I work with modelers sometimes, but I tend to be trying to grab people because I think that there's a big obvious pattern that I can work out in my head, but I'm not going to know the first thing about how to model that correctly, I am not going to be the modeler. I guess the other end of what you said sounded more like you were asking about machine learning type things.

ZIERLER: That's where I was going with that.

BOYCE: [laugh] I don't do that. In paleontology, there are larger data sets that have been around, in some cases for decades. There was a man named Jack Sepkoski. I ended up with his office. He was at the University of Chicago before I was. He made a huge data set of animal life through time. He did very important work with it, but then there has been a lot of work that gets done from his compendium since; less so now, because there's other databases. I tend to prefer to collect my data myself, because that's how you actually see the patterns. If you're abstracting something from a data set that was collected 20 years ago, maybe you'll see something. But maybe what you're seeing is an artifact. If you collect that data yourself, you would have more of a sense of what is going on in that data. I tend to be asking questions where I'm physically measuring a bunch of leaves, and I like that aspect of it. It's dull but, in some ways, that's how you learn what the things look like; not by a machine learning protocol saying, "Here are the five points on the"—and people do do these things, where they say, "Here are the important five points on this leaf." Why? What's the mechanism? What is actually being pulled out here? I have no idea. Whereas, I like the patterns I see myself.

ZIERLER: Is that to say that the amount of data that paleobiology is generating is not so significant, where putting some question into a large language model is not necessarily going to generate an interesting answer?

BOYCE: There are efforts in that regard, and I'm a little far from it, so I can't necessarily speak to how far along they are. But they've been doing it for years. The last time I intersected with those things would've been a couple years ago, so presumably they've made quite a bit of progress. There's definitely value to that. But, for me, it would almost be a secondary thing. I look at the fossils, I look at the record, and then I see a pattern. Then perhaps a way to test that would be to go to something like that. But I wouldn't use it in the sense of telling me what to think about in the first place. Whereas it feels like a lot of that approach, in medicine and stuff like that, they're trying to glean the details that they should be looking at from that. Whereas I feel like those approaches could be useful, but on the back end, where I may have a hypothesis and that large data set would be useful to test it. So, it comes in at a different stage. On some level, yes, it is a small amount of information compared to what gets fed into those huge engines. But there has been a lot of information over the last couple hundred years of information that's been collected. And that data changes over time, so that there are real risks to big data sets, if you're reliant on them without understanding the details of what has been fed into them. It is pretty common to see outliers in those studies where, if you look into it, it comes from some fossil collected in the 1850s where they used the original taxonomy or age and they're not aware of how understanding has changed over the years since for that particular fossil.

ZIERLER: Kevin, some questions about your perspective on the search for life beyond Earth. Your appointment is, of course, in Earth and planetary sciences. Do you see yourself directly, or is there a paleobiological perspective on, for example, once Mars Sample Return happens, and we get these amazing samples back here? Is there a paleobiologist that needs to be present for these discussions to understand what we're looking at and how to interpret it?

BOYCE: They are there. It's all about that. That's not me personally. But that's at Caltech right now, John Grotzinger is there. I think he's no longer as active with that, is my understanding. You'd have to ask John. [laugh] I don't know exactly his status. But the Martian rovers, that first generation of Martian rovers, it was largely Precambrian geologists and paleontologists running things. My graduate advisor Andy Knoll was very much involved with that. Grotzinger—who is now at Caltech, was at MIT at the time—is very much involved with that. Lots of people I went to grad school with who worked in the Precambrian are still very much involved with that. It's specifically the Precambrian end of things, before you had a complex biota—well, at the tail end of that timeframe is when complex multicellular life began to evolve. But there's a couple billion years in there where things were at most a single cell. That is exactly the world from which the people looking at Mars draw a lot of their expertise.

ZIERLER: Is the idea there that the going assumption that if there was life on Mars, it might have existed in parallel with the development of life on Earth, but then the two planets took a very different turn?

BOYCE: Yeah, it works in both directions. Everything on Earth for the last half a billion years is dictated by the fact that there's big living things around, and it changes how sedimentation works, and it changes all the geochemical cycling that happens. Life matters, and big life matters differently from microbial life. First, somebody who is versed in what the world looked like before complex life, particularly what the Archean rock record looks like is exactly who you would want to be thinking about Mars. That's true on this one level. But then there's also what you just said of, yeah, it is contemporaneous [laugh] in that most of those rocks on Mars, they're really old. It is both the correct perspective of thinking about Archean life and Archean environments and the actual age of the rocks. When I say the Archean, that is two and a half billion years ago back to about four billion years. Then before that, we just don't have rocks at all on Earth. The Earth itself and the rest of the Solar System is about four and a half billion. But that first half of Earth history is both the correct perspective for thinking about environments on Mars, but that's also literally how old those rocks are on Mars. Mars does not have the crustal recycling and plate tectonics that happen on Earth, so the average Martian rock is vastly older than the average Earth rock. From both of those perspectives, it is correct that a lot of that work is being done by geologists that work in this older record on Earth.

ZIERLER: Now we'll go way out there in the universe. Between the James Webb and the new generation of ELTs, the Extremely Large Telescopes, all the excitement about possibly detecting biosignatures on exoplanets, is there a paleobiological perspective there as well that we should consider?

BOYCE: For me, at least, it's almost the opposite. I love the fact that I have planetary colleagues here at Stanford. At the University of Chicago, where I was before, that is a very heavily meteorite-focused department, and I loved sitting in on all those talks. A meteorite is just a fossil older than fossils, in a lot of ways. I don't necessarily feel like I have perspective to give them, but they certainly have perspective that I appreciate for me in just understanding the earliest history of our planet and its formation. A lot of value of paleontology for the modern world is just understanding that the way the world works now is not the way the world has to work, and it's been really different [laugh], really, really different at different times. We can freeze the planet, and we can have no oxygen, and all these different things can happen. Then you can take that a step back further, and say, exoplanets teach us that everything within that envelope of what has happened on our planet is a very small fraction of the things that could happen on a planet. So, I appreciate them, planetary scientists. I don't feel they have any particular need to appreciate me [laugh], but I certainly appreciate their perspective.

ZIERLER: This would be inevitably as much a philosophical as a scientific question. But based on all that you've learned about the ancient history of flora and fauna on Earth, does it suggest to you one way or another that life is rare or not in the universe?

BOYCE: I'm on Earth, and I like Earth, and we have life. The reason you can ask and I can entertain that question is because here we are. How frequent that is in the universe, it appears to be rare enough that it's beyond contact. If it happened however many hundreds of thousands of times, but that still means that the closest example is a hundred million light years away, then it doesn't matter. We'll never be able to interact with it, so I don't worry too much on that front. I do worry a little, but I worry about the life we've got here.

ZIERLER: That's the scientist's perspective. [laugh] Kevin, let's go back. Let's establish some personal history now. Where were you before undergrad? How did you hear about Caltech?

BOYCE: [laugh] How did I hear about Caltech? I lived in the area. I went to high school in La Cañada, right next to JPL.

ZIERLER: Oh, OK, local.

BOYCE: Yeah. But I was totally oblivious to Caltech. I didn't necessarily know I wanted to be a scientist. It was in high school that I started to think about those things. I was utterly oblivious to Caltech [laugh], except for two completely non-standard reasons. One, I fenced, like, the sport, fencing. I did that all through high school. At some point, my fencing coach Bob Randolph ended up the fencing coach at Caltech, so we actually moved our practices to Caltech. It was an unusual circumstance. You wouldn't do that at most universities. But it was very helpful for the Caltech team to actually have fencers more than the local undergrad population to help with that. So, I was fencing at Caltech as a high school student, and I knew the team. Also, my then girlfriend, now wife, Gisela, her father worked at JPL, and she was very set on going to Caltech. She absolutely wanted to go to Caltech. Those were my two points of contact. I liked science, but I liked other things too. In the end, I felt like I liked biology, and I wanted to do biology, and so Caltech made sense as a possibility. Then at some point, you have to make a decision, and I ended up at Caltech. I then really liked Caltech when I interacted with it.

ZIERLER: It was biology, not geology, that you were focused on as an undergrad?

BOYCE: Yeah. I did as a major biology, and I did—I believe they call it English now, but they called it literature then. I did those two majors. One of the advantages of Caltech is how much research gets done by students. I was working in a lab the summer before my freshman year. I actually started my freshman year already feeling like, you know what, I'm not convinced that I want to do what biology is here, because it's very molecular-focused, and that didn't really have the appeal to me. But working in a molecular developmental lab—this was Eric Davidson—the summer before and the summer after my freshman year, it was incredibly valuable to have that experience that early.

Whereas if I hadn't have done that, I could have gone through a biology major, graduated, and said, "Well, biology is this pipetting and running gels stuff now, so I'll go to grad school, and do that," and I would've been miserable. It was very helpful to have a chance that early on to say, "I'm not enjoying this. [laugh] Let's look around and think about these things." I wandered into a geology class my sophomore year, and loved it, loved the perspective. I was not going to give up on the other two majors though, so I took some geology classes but didn't switch majors or try to add a third major. And in graduate school, I was still in a biology department. Paleontology can go either way. All my faculty appointments have been in geology departments, but my degrees are in biology.

ZIERLER: Was the early exposure to developmental biology, do you think that was important for you to think about, obviously, developmental biology on a much longer timescale?

BOYCE: It was. Ed Lewis won the Nobel while I was there as an undergrad, so this was all the big deal. Honestly, when I was applying to grad school, a lot of the cool cat paleontologists, and certainly the ones that were interested in me joining their lab, were trying to use the Hox gene revolution for understanding evolution over geologic time. These are genes involved in patterning early in development across animals. Some paleontologists in those days had PCR machines in their little wet labs and wanted to purse this direction in a paleontological macroevolutionary context. But having worked in a molecular developmental evolution lab—and Eric Davidson, retrospectively, he's completely on the nose for having then gone into that direction, but it was just completely random and related to very non-scientific things that I had ended up in that lab in the first place, but having worked in that lab, I could then interview for grad school with different professors interested in pursuing this, and I could sit there and just feel like, well, you're not going to get anywhere. [laugh] I know a bit about how these labs work. I've been a cog in one of those labs. They are huge. They require huge amounts of money and huge numbers of people. The number of man-years that go into a paper are significant.

That's not how paleontology works. It felt like there was a lot of interest but a lot of naiveté about what they could actually accomplish. When I started grad school, that was very much a context that was out there. I didn't know what I wanted to work on. That's another aspect of coming from Caltech is I had no useful knowledge base for a lot of what matters to me now [laugh], I mean, Organismal Biology was a class. It was a good class. It was Tom Brokaw. He was great, but he was a flagella electron microscopy guy. And he taught the one single class that was called Organismal Biology. Then there was one week in that one class where he brought in the gardener, the head gardener from Huntington Gardens, something like that. I don't know what the guy's official title would've been, but he was the guy that was in charge of the plants at Huntington Gardens. And that guy brought a bag of carrots [laugh], and that was my experience with plants. I didn't know anything about anything. In some ways, I was aware that people cared about these things, but I also knew nothing about organisms, except for this one class. How I actually ended up working with plants, for me, came more from being interested in the evolution of development.

What I realized was that plants are the perfect way to go about that, not genetically, but for the fossil record, they were the place to start. A lot of it just comes down to, like, a little epiphany for me that plants have cell walls, and that means they don't have cell movement, and they don't do gastrulation and all these complex weird things that animals do. I can look at a leaf, and say something about how it grew, just by looking at it, because all the development had to happen in place. There has to be discrete zones of growth. I thought that all these paleontologists that wanted to do evolution of development weren't going to get very far, but that I could think of a system where it could be done in a fossil context, and so I went after that. But it very much came from having that kind of context of having worked in a molecular biology lab and understanding where that could and couldn't go.

ZIERLER: Kevin, to go back to your time as an undergraduate at Caltech, what was captivating to you in geology? What was interesting where you thought maybe this is going to put you on a very different path?

BOYCE: I always felt like a bit of a thing apart. I never wanted to be Captain Physics. I very much liked my English major that I was doing, but that obviously wasn't big on campus. I was a biology major, but I didn't necessarily identify with the biology there. I knew by sophomore year that the kind of biology available wasn't necessarily where I wanted to be in a lot of ways. Now, I have to think. I don't know if this was sophomore or junior year, but it was somewhere in that phase that I wandered into an East Asian art class, which was great [laugh], but I wasn't about to pursue that. And I took a geology class. In the geology class, it was Brian Wernicke, who I believe is still there.

ZIERLER: Yes.

BOYCE: It was I think the first homework set, it might have been the second homework set, but one of the first two homework sets was one problem. It was really obvious, and I did it. It was just a strat column. It was three different blocks of rock, and the question was just like, "What happened? Reason through what's going on here." The answer was obvious, and so I turned it in. I got it back, and my grade was two out of ten, and I think the two was generous. It was basically I got zero out of ten. Then he explained it and why, in fact, the rocks—the obvious answer is to say the rocks on the bottom are the oldest, and then the rocks in the middle, and then the rocks on top. But in this case, the rocks in the middle were oldest. You had to flip it over, and then add some rocks, and flip it back, and add some more. It was just a cartoon diagram. But you look at it and, once it was explained, it was like, yeah, of course, that's how it has to work. But it was just so far beyond common sense that [laugh] I really liked the idea that I could be that wrong about something that had felt that obvious. It just felt like, yeah, I like that.

ZIERLER: [laugh]

BOYCE: Actually, it was years later, as I sat in a seminar that I wasn't enjoying, when I had to teach the equivalent class to that first geology class I had taken, I sat there, and I worked out exactly that same problem so that I could pounce on my students with it. [laugh] But I very much appreciated just how different the perspective is, and how much things change if you just multiply it all by 100 million years, and what can happen and can't happen, how different things are.

ZIERLER: Now, of course, we have Dianne Newman, Woody Fischer, and Victoria Orphan. But when you were an undergraduate, was there anybody that was cross-listed or was thinking about intersections between geology and biology at Caltech?

BOYCE: Yeah, that's Joe. That's Joe Kirschvink. By my sophomore year, I didn't want to work in a molecular biology lab, but I wanted to do something. I guess it must have been sophomore year that I took that geology class. So, I had taken one or two geology classes. And the summer after that—these are all SURFs, basically—I started working with Joe Kirschvink. I was not doing anything remotely related to geobiology with Joe. I was working with bees and magnetic sense. But that lab was very diverse, and I really appreciated just how Joe's lab was good at being this island of misfit toys.

There was a number of undergrads there that were somehow unhappy someplace else in their education, and kind of wandered in there; people that I still know and I'm colleagues with. I forget what majors they came from, but they wanted something different from what they were getting. Joe's was a lab with lots of different weird things going on in it. It was fun to just, you know, you could propose something crazy. "Sure, go do it," and then you do it, and see if it worked or not. I appreciated that, even if what I was doing was not related to what I ended up doing in any way. Just the context of the issues that were being thought about were very helpful and relevant.

ZIERLER: Once you set your sights on graduate school, what kinds of programs were you considering? Was it all about paleontology?

BOYCE: I did a biology major that I didn't necessarily identify with, but it was useful. I took geology classes, and I liked them a lot, but I didn't take that many. I did a literature major too and that was, in some ways, the most useful, in that I really liked the older literature. George Pigman, I don't know if he's retired or not, but he was my major advisor for that. I took more of his classes than from any other individual prof. But I really enjoyed the English major, because there was a small group of kids that were taking those classes. Any one day, two out of the three might not show up, and you just end up talking to the professor for an hour. It was great. It was great. I really enjoyed those. I particularly appreciated Pigman's classes, because he taught on the earlier end, like, the Chaucer end of things. I really liked that literature in the sense that there's modern movies where people have swords and dragons and stuff, but they're very clearly modern people with swords and a CGI dragon. Whereas when you read Chaucer, you can try to make sense of it in a modern context, but you will fail. They will make decisions, these characters, they will do things that like, yeah, I'm out. I have no idea why they just did that. [laugh] It made sense to some author then, but it doesn't make sense in any kind of a modern context of what's going on in this story. I liked that. I liked that it could feel normal in a modern sense, and then something would take you out of it, and make you realize that, no, you're seeing something different.

Paleontology is very much like that, where I can think about forests 350 million years ago, and you can go, OK, it's a forest. I know what forests are like. Then you can add in: by the way, that forest doesn't have herbivores. Because herbivores haven't evolved yet. [laugh] You feel like you understand, and then just something pulls the rug out from under you, and you go, oh, that is different. That isn't the world we occupy. Let's think about that. Just I liked those types of problems of trying to figure out what was going on, whether it's a fossil or whether it's a really old book. In some ways, the pleasure of dealing with that kind of question, that kind of problem is similar. It just felt like I wasn't, I mean, I'm terrible with foreign languages [laugh], so I wasn't going to go into the literature. I liked biology. I just didn't want to do molecular biology myself. It felt like the correct way to blend that would be paleontology. I just tried to do it, and it worked, but I suppose it was a fairly risky thing to try to do.

ZIERLER: Now, I asked about the potential value of developmental biology. What about with your love of literature, the narrative, the storytelling aspect, because isn't it in some ways what you're doing ancient history?

BOYCE: Absolutely, it's very much history, that's exactly right. If I think about my undergraduate days, is there a single fact that I learned that I use? [laugh] No, not particularly. I work in synchrotrons, and I can talk to those people, but it's not like I learned from Phys 2B how to run a synchrotron. That's not what I'm actually using. What I learned from Tech was, first, there's a wonderful aspect of Caltech where it's all about doing it. I loved that from day one, like, the weirdest thing starting as a freshman, one of the first things I noticed was that people didn't talk about being a physics major or a biology major. They just said, "I'm a physicist," or, "I'm a biologist." From day one, as freshmen, that's how people identify. It is not "well, I'm intending to do this." It is "this is what I'm doing." That's a very useful aspect of it all. That was totally [laugh] a tangent from what you asked me—

ZIERLER: No, that's great.

BOYCE: —about the narrative. But you notice that very much. I feel the English major is very relevant to my life as far as how do you construct a narrative? How do you follow this narrative? How do you explain this to people? It's totally relevant. The same girlfriend, now wife, she started an MD/PhD as I was starting a PhD. So I knew, no matter what I did, I was going to finish before she did. [laugh] So there was no time pressure on me at all in that sense, and I spent a lot of time at old vintage movie houses. I figured that that was another part of my education that, to that point, I had neglected, and I could learn a lot about narratives and storytelling. Because story telling is absolutely what scientists do. If you can't write it, then it didn't happen. If you can't write it down properly in a way that people understand, then you never did it. Writing is very much a part of it.

ZIERLER: There must have been a two-body problem that led you to Boston?

BOYCE: Yeah. It wasn't so much a problem…I mean, it was a weird. Back then—and I don't know if it's still true now—but back then, people applying to science grad schools would apply to three places, or something like that. People applying to med schools applied to like 50 places. Because she was in that situation of sending out many applications, I applied to lots of schools just making sure there were geographically relevant options to the net that she was casting. I got rejected by some places. Retrospectively, I look and go, oh yeah, you don't actually have any paleontologists. [laugh] What was I thinking? What was I doing applying to that program? But I know what I was thinking. It was like, oh, WashU is a good med school, so I'll apply to WashU since also being a good evolution program. Wherever she was applying, I'd find the closest school that appeared to have an evolution program; not necessarily always appreciating that evolution is not the same thing as paleontology. It worked out well. We both went to Harvard, and that was a good school on the med school side of things too. But there are always complexities to these things.

ZIERLER: Tell me about the paleontology program at Harvard. Is it one of the ancient disciplines?

BOYCE: Yeah, and I had a very good advisor, Andy Knoll. I was in the Museum of Comparative Zoology with all the specimens, and I loved walking through that museum. They had the kid groups coming through every day with the school buses. It was a wonderful place to be in that sense. It was a really good crew of students at the time. That's something where you can't really understand at the time but, retrospectively, I still know and respect a lot of people I knew as an undergrad at Tech who are scientists now—colleagues even, there are 4 or 5 Stanford faculty for whom we all overlapped as undergrads at Tech—and we were all there in the same years, often the same house. Similarly with grad school, the people I went to grad school with, they're still doing interesting things. It's nice to see that progress.

ZIERLER: Coming from the biology and literature undergrad, what was your steepest learning curve in paleontology at Harvard?

BOYCE: [laugh] I didn't know anything. The way it worked then was—I don't know how it works now—but your first week as a grad student, there would be a little committee, and you would meet with the committee. There were no fixed requirements, but they would look at your record, and they would basically say, "You can do whatever you want, but here's a couple things you have to do." Most people came out of that room having been told, "You really should take a chemistry class," or, "You need some more math." [laugh] That was not what I got. I came out of that room, and my fellow new students asked, "What do you have to take?" And I was told I have to take a plant class and then an animal class, because that's the stuff I didn't know at all. It was a lot to learn. I had everything to learn, basically.

In some ways, the steepest learning curve was just appreciation of natural history and the geologic record. Caltech, it's diversified since then, but still, I would imagine, is very much on one end of what science is. You don't have collections. You don't have an herbarium. You don't have ecology or much in the way of organisms. There are drawers with rocks in them, but they're often thought of more in a geochemistry context. Probably the steepest thing is understanding what one can do with specimens, and appreciate that. There are very different kinds of scientists out there, some of whom will dedicate their lives to salamanders—and, good lord, do we need those people—and just appreciating what you can get from that end of the scientific world too. Coming from Caltech, that was probably the steepest part of that curve.

ZIERLER: Tell me about Andy Knoll's research. What is he known for?

BOYCE: He just won the Crafoord, right? [laugh] Really, you can look him up. He largely works in the Precambrian. There's an interesting kind of foible of Earth—well, not Earth history but the history of Earth history—in that his advisor was Elso Barghoorn, who was the first guy to identify Precambrian fossils. Going back to Darwin, there was this understanding that there was no life in the oldest rocks, and then suddenly we have life. What that really meant was life that could be readily seen, big macroscopic multicellular fossil eukaryotes, and stuff like that, clams. What Elso did in the '50s—this is Barghoorn and Tyler, and Tyler and Barghoorn in the papers—but he was the first guy that showed microbial fossils of single cell prokaryotes, bacteria-ish things, deep in the Precambrian.

Elso was trained as a paleobotanist. He worked on wood before Precambrian microfossils. Precambrian paleontology came out of paleobotany, and so there's always a little bit of a jointness to it all. My advisor Andy, 95% of the time, he was in the Precambrian. But he did think some about fossil plants in later time, and he taught those classes. He was the curator overseeing those collections. He would often have one student that worked in the Phanerozoic and the more recent Earth history. Again, that was very useful, because the perspective you use in Precambrian paleontology is distinct from the perspective typically used in the Phanerozoic. When you have a big complex fossil, it's easy to get hung up on little details. Whereas if you're working in the Precambrian, you've got [laugh] next to nothing. You've got a tube or something like that, and you really have to stop and think about what can I say about this tube? Does it taper? How thick are the walls? These very basic questions, and then ask, "What does that tell me about how this could have functioned as an organism?" I largely tried to take that, what's almost a Precambrian approach, and then apply it to larger, more complex later fossils. I very much appreciated that perspective.

ZIERLER: Did you come to Harvard to work with Andy, or did you develop that relationship in real time?

BOYCE: Pretty much to work with Andy, yes. There are definitely fields of science where you admit cohorts, and then they find labs and do rotations. Paleontology and geology in general, more organismic or evolutionary ends of biology, you're usually in a situation where you're going to work with somebody in particular, because if that person wasn't there, and based on what you wanted to do, there would be no one else to work with. You had to know that that one relationship was in place. People do change directions sometimes, but you tend to go to work with a specific individual.

ZIERLER: How did you slot into his research group at that point, in terms of what you wanted to focus on, in terms of what the group was doing?

BOYCE: They were doing other stuff. Andy's a broad thinker, and so he was perfectly fine with that despite everyone else was working in the Precambrian. Later on, there was one guy who worked on the Permo-Triassic extinction, so there were different directions. I was the guy that ended up working on plants. People worked on different things. The majority tended to be in the Precambrian. But if you had an interesting question, and it somehow intersected with life and geobiology and these things, then he was good with it.

ZIERLER: Now, was there a fork in the road moment for you where you said, "Either I'm going to concentrate on field work or I'm not"? Did that happen during grad school?

BOYCE: Yeah, a little bit, in a sense. For me, what it was, I didn't like the uncertainty of field work in the sense that I wanted to ask a question, and answer it. It felt like with a lot of field work, particularly Precambrian field work, for Precambrian paleontology, it was fairly exploratory, and there was an aspect of just saying, well, we know rocks of the right age are present in this place where people haven't looked. We know something about the rock types. So, there are probably interesting fossils here. But then your thesis becomes whatever you macerate out of those rocks, and I did not want to do that. I wanted to ask a question, and then try to answer it. That was the fork for me of wanting it to be driven in that way, by having a question I was trying to answer. Now, retrospectively, there's lots of questions you could ask in a field context. [laugh] But given my limited perspective and my knowledge base at that point, that was a pretty clear dividing line for me at that time.

[unrelated conversation]

ZIERLER: Kevin, what was that question? How did you go about answering it for your thesis?

BOYCE: My thesis ended up being half leaf development, and that was a very useful system because leaves evolve more than once, and they all kind of look the same. I had already felt like they were going to be a useful tool for looking at the evolution of development. It was a very useful to be able to say, OK, we have four or five iterations of the exact same experiment, with leaves evolving independently, all going on at the same time, 300 million years ago. Can we get at why this is happening? Then the other half of my thesis ended up being chemistry of fossils. And this gets back to the same advantage of plants having cell walls in that plant fossils tend to have anatomical preservation. You can get the right nodule of carbonate or chert or something. And if you make a section through it, you're looking at the complete anatomy of the plant fossil to the cellular level. Often that involved remnants of the original organic matter. So, the other half of my thesis was using that cellular preservation of fossil organic matter to get at the evolution of cell wall biochemistry, and what compounds were involved in those cell walls via the isotopic and organic chemistry that is preserved in place within that fossil anatomy. T'at's something where the key for me was that people had done chemistry of fossils before, but it tended to be grinding it up, and then handing off the powder to a chemist. Once you grind it up, you're actually losing the most valuable chemical information you will ever have, which is the anatomy. But if you can put that anatomy in the context of an evolutionary tree, a phylogeny, you can already know something about the original chemistry that would've been present in the original organism. Then you can look at how that remaining fossil chemistry has been cooked and altered over hundreds of millions of years, because you're maintaining that anatomical context with in situ chemical analyses. It was important to keep that fossil context for the chemistry side of things. So, the question on that half was, we can watch the evolution of vascular cell types in these earliest fossils, is that also tracking the evolution of the cell wall biochemistry unique to those cell types?

ZIERLER: Now, with these two halves of the thesis, what was the connecting point? What was the connecting story?

BOYCE: It was all the early establishment of complex plant life. So the oldest well-preserved plants are from a place called the Rhynie Chert, which is 410–417 million years ago, something like that, which is Early Devonian. Those plants are about the width of a pencil, maybe 20–30 centimeters tall. They didn't have roots. They didn't have leaves. They had nothing. There was no wood, none of that. It was just a stem with a little bit of vasculature down the middle, and then some photosynthetic tissue around that. That's the whole plant. That's the Early Devonian. By the Late Devonian, 30 million years later or so, you had trees. Already by the Middle Devonian, you had big woody trees; by the end of the Devonian, trees had evolved four or five different times. Then as you move on to the Carboniferous from there, roots have evolved two or three times. Wood has evolved seven or eight times. Leaves have evolved four or five, six times. All this is happening at the same time in parallel in all these different groups, most of which have some kind of remnant of descendants that are still alive today, so that you can think about the living versions of that too. The biochemistry of the cell walls is at the very beginning of that, and that's Early Devonian—that was the Rhynie Chert—and then the tail end of that explosion, like, the other bookend of all of that was all these organs appearing, the leaves and so on. But it's all very much tied to being either end of this explosive diversification of form.

ZIERLER: Is the field mature enough at this point where there are dogmas to challenge, or are you really present at the creation of these questions?

BOYCE: Oh no, there are plenty of dogmas out there [laugh], and there are certainly ones I've had to confront. Paleobotany, in some ways, was a mature field, and has been for a long time, going right on back to Victorian scientists. I still use literature with some frequency from the 1890s or 1920s. The first Rhynie Chert work was in the 1910s-20s. The earliest papers on that were back then. There's definitely old problematic ideas and interpretations that you have to work through and that, to me, is part of the fun. That's what I was referring to in some ways earlier. People had these ideas, and they even in some cases had the information where they could've gotten the right answer, but their perspective was so different that they didn't know how to put those pieces together. Then people start to, you know, they almost get, you know, not—"ashamed" isn't the right word. But people stop asking those questions. They feel like they're old fashioned questions. But, no, actually, now we can answer these questions. It's fun to think about these things now, where does this plant life come from, and how does it get constructed?

ZIERLER: I wanted to ask you before about Mars and exoplanets, because I know where you head after Harvard, the NASA Astrobiology Institute. Were you thinking about astrobiology? Was that a cool place to continue paleobiology? What were the considerations there?

BOYCE: No. [laugh] So, the chemistry I did as a grad student was not Harvard-based. That was at Carnegie Geophysical Labs in D.C.

ZIERLER: Ah, OK.

BOYCE: I worked with a guy named Bob Hazen there, and worked with him first, and then also George Cody and Marilyn Fogel. Bob and George are still there. Marilyn recently passed. I remember the first conference I went to, after my first year in grad school, that was when the Martian meteorite went nuts, and they had that press conference announcing life, and everyone was suddenly talking about this. That was the first conference I ever went to as a grad student; it was a botany conference, but everybody was suddenly talking about Mars in the hallways and at lunch. It was that week that that happened, and everyone went crazy. NASA realized—and I'm not privy to any [laugh] of the actual logic that went into this. But from the outside, as a young grad student, what appeared to have happened is that NASA realized they had a hit on their hands. They in some ways realized also how much astrobiology could be done for very little money. For the cost of one satellite, you could fuel all of paleontology for 100 years. [laugh] There's actually a lot of science that could be done a lot cheaper than a billion-dollar satellite. Over the course of when I was a grad student, they started building up what became the NASA Astrobiology Institute. It was first actually properly established with a postdoc, right when I was finishing. They were based on hubs, so they had hub institutions. Carnegie was one for origin of life stuff where George and Bob were very involved with that. Harvard and MIT was another hub from the Precambrian paleontology side of things. I had connections to two hubs, and I needed a postdoc. [laugh] I independently applied for postdocs via Carnegie too. I also was working with Missy Holbrook, which was my main base, which was still at Harvard. NASA was flexible about that, allowing me to float in that sense, so I spent most of my time working in Missy Holbrook's lab, which is plant physiology and modern plants. But I could then still float back and forth, and work down in D.C. with the chemistry and the fossils.

ZIERLER: Despite the name "astrobiology," this is really much more of a seamless continuation of your graduate work?

BOYCE: It was. You have to justify yourself. I still had an application where I explained the relevance to astrobiology, but I've never left Earth in that sense.

ZIERLER: When were you ready to go on the job market? When did you feel like you had enough to give job talks?

BOYCE: It just kind of happened. I ended up in Chicago, which is a wonderful place to be for paleontology. The way their system—I think they've changed a bit since then—but the way it tended to work then is they didn't have job searches; every departmental seminar was a job talk. Then if they were still talking about you a couple months later, then they thought about, "Maybe we should get an application from this person, and see about hiring them." As a grad student, there were some analyses I was doing with the leaf evolution, where I had to look at morphological change through time. The person who had worked out the math on the paleo side of that was a guy named Michael Foote, who is at Chicago. I was having trouble figuring out how to do it myself. I ended up in an email argument with him over this. It turned out that I had basically forgotten to multiply by negative one at some point. [laugh]

ZIERLER: [laugh]

BOYCE: I ended up with this analysis with all these negative eigenvalues. He's like, "I don't know what this means. This can't possibly be right." I'm saying, "But it's multiplying by a constant. What does it matter?" It turns out that I had actually forgotten somewhere in my code the minus one. But it was an interesting enough conversation that I was invited to give a talk there. I guess I had defended my thesis at that point. Maybe. I might not have defended my thesis yet at that point. But they liked it, and eventually I got a job out of it. I didn't really give a job talk and know I was doing it [laugh] until later in my life.

ZIERLER: You mentioned Chicago is a great place to do paleontology. What were the areas of strength among the faculty there, and how did you fit in?

BOYCE: It's a very quantitative place. I've mentioned two people now, with Jack Sepkoski earlier. He basically quantified the animal fossil record through time. There are wonderful colleagues there, and there's a density of people there between different institutions and in the university itself. Within the geology department, there was me plus four other paleontologists. Then in the larger university, there was also paleontologists in other departments and a lot of evolutionary biology more broadly. They have the Committee on Evolutionary Biology that is 50–60 faculty. Plus, down the road was the Field Museum, which had its own curators that included expert paleontologists too. The density of paleontology in Chicago is not like any place else in the US. The university itself also is known for a particular way of being, and that's where quantitative paleontology is centered. A lot of the big names that have gone off in that direction, they were all grad students there. I wasn't a grad student there but, in some ways, I feel like I was, because I learned a lot while I was there. But it's a wonderful department.

ZIERLER: Do you have a sense of the history at Chicago, why it became a leading center of paleontology?

BOYCE: There's an earlier generation that was already gone by the time I was there, with David Raup and stuff like that, who were doing amazing things back in the '60s, and basically the first people adopting computers in using this kind of data. He has these fabulous studies, where he's using an oscilloscope to look at snails' shell shape. They were doing very interesting, innovative stuff. In a lot of ways, Chicago is the closest I've ever been as far as the culture to Caltech, more so than MIT. Chicago's much more like Caltech than MIT is.

ZIERLER: Oh yes.

BOYCE: I took classes at MIT as a grad student a little bit. Whereas Chicago has the humanities more than Caltech does, but the attitude is very, very similar, the dedication, and just how invested you are in what you're doing academically. [laugh] They have the Divinity school, and they'd have T-shirts. The T-shirt said—what was the correct phrasing? It said, "Well, that works in practice, but how does it work in theory?"—

ZIERLER: [laugh]

BOYCE: —so that was even the Divinity School there. [laugh]

ZIERLER: [laugh]

BOYCE: Chicago paleontology had that reputation, but apparently even the Divinity School is like that. It always amused me to see that T-shirt around. It felt very much like Caltech. You guys have a president that you took from Chicago, right?

ZIERLER: That's right.

BOYCE: When that happened, that made perfect sense to me. He was my provost over at Chicago.

ZIERLER: Did you interact with Tom Rosenbaum?

BOYCE: Sure, in the sense that I probably twice sat around a table at a lunch where they had assistant professors, and he was at the head of the table, and everyone said a couple words about themselves, but not on a one-to-one basis. I was an assistant professor. That's the last thing I would need to be doing, interacting with the provost.

ZIERLER: What was your research agenda, starting out? What did you want to do as an assistant professor?

BOYCE: I continued a lot with plants. [unrelated conversation] Over that time I branched out a little bit more into the physiology side of things. I had worked in a physiology lab as a postdoc with Missy Holbrook, but I didn't do physiology when I was there. I was surrounded by those people. I learned a lot. But what I was actually doing was testing the results from my thesis. Whereas in my thesis, I said, "This is how I think leaves evolved and how development changed, and how I can parse that out in the fossil record." Then I got an NSF grant to then test that with living plants. I went to living plants where no one had looked at the leaf development, and I could have a hypothesis based upon the vein network of the leaf as far as how I think it had to grow. But then because it's a living plant, I could actually verify that. So, what I was doing in practice was developmentin a physiology lab, just because that was the next step from my thesis and why not do it there? But after having left that lab, I started thinking more about the fact that the same vein networks that I was using to look at development, that's how a plant works: the veins, because for a plant everything's about gas exchange. You have to take carbon dioxide in to do photosynthesis and make sugars, but you cannot help but lose water in that process. You have to be able to lose water, and that's where the pipes come in. The arrangement of veins moving water around in a leaf says everything about how much photosynthesis can be done based upon how quickly you could replace the water being lost. It was this after-the-fact recognition that it was a way to look at physiology through time that then ended up having implications for climate, because all that water that plants lose is actually a big deal for climate with transpiration, the movement of water through plants, from the ground through to evaporation from the leaf. If you go to a modern rainforest, up to half the rain that falls in the rainforest has been recycled from that forest. It falls out of the sky, and then the plants put it right back up into the sky. There's big obvious patterns, once you bother to look in the fossil record, of how that changed through time based on the density of veins in fossil leaves that would have impacts for the carbon cycle and climate and all these different things. Figuring out that stuff was a lot of what I was actively doing then.

ZIERLER: What was the tenure culture like at Chicago? Did you feel supported? Was the idea that gaining tenure means that everyone wins?

BOYCE: I felt very babied. [laugh] I felt very supported. I'm sure in part that's because I had very good senior colleagues within paleontology with Foote and David Jablonski and Sue Kidwell. I don't necessarily know that that would always be the case. It felt like if I did my job, and I did interesting work, I would be ok. I mean, you worry about it because if you don't worry about it, then that's when you should have been worrying about it. But it's not like I felt like I was going to be screwed over or not appreciated. As long as I did good work, I felt like it would be appreciated.

ZIERLER: You said there were no job talks. Are there tenure talks? Is there an opportunity to do a retrospective about what you've accomplished so far?

BOYCE: They don't need that there. Actually, you have to give a talk every year, and it's this very special cultural ritual there of everyone has to give a talk every year. You don't know you're giving it until the day before. You just do that, year in and year out. You don't need the job talk at the end.

ZIERLER: You have to always be ready, essentially?

BOYCE: Yeah. You have to do it. You do it all the time.

ZIERLER: Was Argonne or Fermilab ever an asset for you?

BOYCE: A little bit. The first synchrotron I used was NSLS, which is at Brookhaven on Long Island. I was going there with George Cody from Carnegie. At some point, I was using a place called the SRC in Stoughton, Wisconsin, which is the Synchrotron Radiation Center, which is like a first generation—that place, I don't think it's still open. It was very old. Argonne, I did do some work at Argonne there, but Argonne was almost—there's this weird issue of just the beam was too pure and too strong. You fry biological samples when you put them in those beam lines. Over the generations of synchrotrons, they were getting more and more intense. It was relevant to X-ray crystallography, and understanding protein folding and all those types of things. But it just wasn't necessary for the types of specimens that I worked on. It was too much. The techniques being used, this is XANES, which is X-ray absorption features, and if you look at the ionization edge, you'll get a big jump in the absorbance, and then there'll be little wiggles along that edge that say something about the bonding environment. It means you can look at the bonding environment of carbon in these plant fossil cell walls at this submicron scale, and be able to differentiate the chemistry of different wall layers. I did work a little bit at Argonne, but that was getting more into CT scanning of things; it's not the chemistry end of it.

ZIERLER: Kevin, what were your teaching responsibilities at Chicago? Are undergraduates interested in paleontology? Are there courses for them to take?

BOYCE: For every geology department with a major, Earth history is a course that is required. I took it from Kirschvink when I was an undergrad, and I taught the same class at Chicago. Because there were so many paleontology faculty, there was a lot of grad students, so there's a lot of opportunity to teach at a graduate level. I think I mentioned I taught a class in the evolution of terrestrial ecosystems in that kind of context.

ZIERLER: Tell me about the intensive University of Chicago undergraduate. I know it's such a demanding place.

BOYCE: It's very similar to Caltech. [laugh] It felt very similar, even at the level of, you know, they have a scavenger hunt versus Ditch Day. A lot of it felt very, very similar. They were dorky in the same way that we were. [laugh] It was very comparable in a lot of ways.

ZIERLER: What about grad students and postdocs? What kinds of students would be attracted to join your group?

BOYCE: There's a long history of paleontology there. So, there were even undergrads that would show up wanting to be paleontologists. They made their undergraduate institution choices based upon that, and that was weird to see, because that's not where I was [laugh] as a high school student. But there were very good students that were attracted to that.

ZIERLER: Did your research change as a result of gaining tenure? Was there an opportunity to be more adventurous or to delve into new fields once you were established?

BOYCE: I moved two years after that. It certainly did change over that time. It had as much to do with moving, I think, as just tenure. In some ways, there's no change in pressure with tenure. You still had to give an interesting talk every year. You've got to account for yourself on a yearly basis. That didn't change so much then. Also, I had a lot of kids. [laugh] We had three kids in two years late in our time in Chicago. That's largely why we moved was to be closer to family. There was a reset of just descending into the chaos of three toddlers, and then reemerging from that. [laugh] That's a far bigger deal than tenure. That was the big reset in a lot of ways was no longer having three young kids, and then trying to remember what it was I had been doing before that.

ZIERLER: Now, just a chronology question. The MacArthur Fellowship begins in 2013. You joined Stanford in 2013. Are they connected at all? Are you getting on Stanford's radar as a result?

BOYCE: No. That was as I had just already moved and Stanford really didn't even know I was there. That was wonderful. Wonderful, but was weird. That was all for work that I had done in Chicago, basically, and so I felt a little guilty. You get this phone call. I was at lunch with a colleague. And the previous time I had tried to eat lunch with him, I had a kid throw up at day care.

ZIERLER: [laugh]

BOYCE: [laugh] So, when I got taken away by a phone call, he was like, "Yeah, he's got another sick kid." But you're supposed to be secretive about it, and then they do this little video of you. I had just moved. They wanted to do a video, and I had no fossils. I had nothing. I didn't have an office. I had no books. I had nothing. They had me walk around campus, and then I came back to my temporary office. They had taken every single thing I had, which was three books and a couple of stray little plants. They had put them in this narrow little arc on my desk so that they could film me [laugh] with something behind me, because otherwise there was nothing in the room.

Then when it was finally announced, that day—because you have no control over this; there's the day where they announce these things—it was mortifying. All my lab happened to have arrived the night before, so the lobby of the building had all these pallets wrapped up in plastic with my microscopes, and it said "Boyce" all over it. That happened to be the same day that they announce these things. Stanford didn't even know who I was. The people that worry about those things from a PR perspective, they didn't know that I was there. Another person from my same school also won that year, and so they were aware of him, and they thought they were done. Then at some point, someone said, "There's actually this other guy you need to talk to too." [laugh] But it was just all in the middle of that transition that that happened.

ZIERLER: It was mostly to be closer to family? That was the primary interest?

BOYCE: My wife is not large. As far as surface area to volume, the heat transfer of Chicago winters were—

ZIERLER: [laugh]

BOYCE: —[laugh] hard on her. We had three small kids. All of our family lives in California. You can always retrospectively make scientific justifications of why it's an interesting thing to do. But as far as actually pulling the trigger, I had no innate wanderlust. I was very happy in Chicago. But it was for family reasons. It made a lot of sense to move.

ZIERLER: Thinking back to La Cañada, did you consider Caltech? Was that something to consider?

BOYCE: Yeah, and I gave a talk there once. It didn't go very well. It was actually very instructive and I look fondly on the experience. There was one time where I gave a talk at Tech, and it clearly was a job talk that was not a job talk, and I did terribly. [laugh] It was very instructive. It was one of those things where I walked in, and I thought, "I have this." I was a Caltech undergrad. I know what Caltech's like. I'm in a geology department now that is very modeling heavy. It's very meteorite heavy. It's very much like GPS at Caltech. Then I gave a talk, and it was just lead balloon time. [laugh]

The energy level afterwards was just non-existent. It was very instructional and educational because I realized that, yes, in Chicago I was in a very similar department, but it was a similar department that, year in and year out, all those modelers and meteorite people had to sit through five paleontology talks, because everyone gives a talk every year. In the same way that I understood meteorites in a way that I had no business understanding meteorites, they understood fossils in a way that they had no business understanding fossils, because they're so exposed to it. That just wasn't what was there at Caltech. Even though I thought I knew exactly what I was doing, and I was sure I had this under control, I did terribly. [laugh]

ZIERLER: Administratively, where does paleontology sit at Stanford versus Chicago? Is it in that sort of Earth and planetary science program?

BOYCE: My department at Chicago was Geophysical Sciences. Then at Stanford, we've changed the names a couple times. When I joined, it was Geological and Environmental Sciences, and we've since changed to EPS.

ZIERLER: Did your research change at all as a result of moving to Stanford?

BOYCE: A little bit, because there were more people invested in rocks and that end of elemental cycling. It's part of the fun of being influenced by your colleagues. It was influenced a little bit also, honestly, a little bit by the MacArthur, and the fact that the—

ZIERLER: Yeah, I wanted to ask.

BOYCE: —and the fact that I was coming back into this after, largely, taking kids to day care [laugh] for a lot of years, and changing diapers. I was getting a lot less done, and you can see it on my CV. Moving institutions, winning awards, they could not have happened two years later, because you could look at my CV, and see, "Well, what's this gap here?" [laugh] where I just didn't get anything done for two or three years. That's what it was. So, it was a chance to reset, and it was very nice. That sounds weird, but it was nice to have somebody go, "We noticed what you did, and we liked it," and just to have that chance to think about it and go, "As I get back into this, what do I want to do with myself?" In part, it felt like I should try to do something bigger and different. In part, I wasn't going to have to give a talk every year like in Chicago, because that's not the culture. That, before the move, in some ways, lends itself to a little bit of a fast turnover of knowing you're going to need to complete something quickly so that you always have something new to say. Now, I was more open to just thinking about what's something big that I could do that's different from that? It did change in that sense.

ZIERLER: Is this also when you start to become involved in—I don't know what the right term is—public outreach or science communication?

BOYCE: I've never been too involved. If anyone asks, I talk to them. I've never really gone too far in that direction as far as seeking it out.

ZIERLER: Fun things like the Smithsonian or local zoos, things like that?

BOYCE: It's always been a question of if someone asks then, yeah, I'm happy to do that. I was once the scientific advisor for a sticker book. [laugh]

ZIERLER: [laugh]

BOYCE: It was fun. I actually felt in the end I had some useful insights to give them about those stickers. But I've never gone in for that. The selling aspect of it, I guess. That's not the right word because there are some people that are trying to sell themselves, and there's some people that are legitimately trying to do something helpful for the world. But that outward kind of drawing attention to it, I've never been the best at that. [laugh] But I'm always happy to do it when somebody asks.

ZIERLER: Now, I wanted to go back to the impact of the MacArthur Fellowship. Between notoriety, in terms of the funding, how did it change things for you?

BOYCE: Less than you might imagine in some ways. Your colleagues know, but a couple years later, no one cares. It's a blip. Then on some level, I don't know if my junior colleagues know that I have that or not, and why should they? Who cares. On some basic level, who cares. It is a very brief notoriety. It was a wonderful morning of interesting emails. The morning of, the same morning, you're still checking your email like any other day, but they were very sweet emails from people congratulating. But then that doesn't last. It's not like I try to parlay that into a TV show or something like that. The money can be transformative for the artists and writers, but that isn't there in the same way for a salaried academic scientist. I had three kids in day care, so it helps knowing that there's a buffer there to just take that kind of pressure off of things for those years when the kids were so young. But, honestly, it's on par with an NSF or various other grants available for academic scientists. It's not more or less than that. But it matters more to have a weird phone call and be told basically, "We like the stuff that you've been doing, and so go do more of it." [laugh] That's very nice in that sense.

ZIERLER: Kevin, your administrative service, your academic leadership ultimately culminating in being chair of the department, was that something that you embraced? Did you get a tap on the shoulder, and you're willing to do it? What's your perspective on that?

BOYCE: Anyone who wants to do it probably shouldn't do it.

ZIERLER: [laugh]

BOYCE: [laugh] I had no desire to do it. But there was every reason in the world to do it. The colleague that was chair became an associate dean type of thing, and I was the obvious next person in line. You never want to shirk your duties, and someone's got to do it. Being in an academic department is like owning a house. You've got to make sure the water heater works, and there's a roof, and everyone has to do their part. As you age, that part changes. I was happy to do it. It was a weird time to do it. I started in January 2020 [laugh], so I don't really know what the job is supposed to be like. There was nothing but COVID, and then they blew up the school that we were in, and made a different school. There were no normal times associated with it. I was happy to do it and happy to no longer be doing it. [laugh] It's more kind of everyone should do their job, and sometimes that's part of your job.

ZIERLER: You're chair, and then a couple months later, COVID hits. What are the most important considerations for you in terms of your own research, in terms of education and remote learning, in terms of your fellow faculty members? How did you deal with it all?

BOYCE: It's mostly just, at that point, the whole—and I'm sure this is true anywhere and not just where I was—but you just become a cog at that point. There's university policy, and you are an instrument of university policy. You don't wing it, as far as how do we handle these things? There is just a series, like, it was continuous meetings straight through summer for two years or whatever, however that went. But you're largely receiving information, and then transmitting it. You don't make individual decisions of, well, how many people will we allow in the building at a time? Those aren't decisions that are handled at that level. You have a little bit more control about worrying about your own department and the fact that you have students who have never set foot in the department, because there's still admissions and all these types of things going on. There's things to worry about, but it almost becomes worrying about what will it be like once this stops, more than the day-to-day of during. It is largely out of your control, unless you're actually the acting officer for the university.

ZIERLER: What about in terms of teaching, in terms of online teaching? What did you learn that worked, and what did you learn that didn't work?

BOYCE: In some ways, I really liked COVID, because I was suddenly, you know, at that point, our kids were late elementary school, and we were suddenly at home with them for two years. [laugh] It was nice to not have all the running around with soccer practice, and just to be home and not do all those busy things. It was good for us. Then there's clearly students who weren't in that kind of circumstances. There was a lot of variance in what was going on in people's lives. There's certainly lots of allowances that had to be made for all of that. I didn't mind online teaching. The type of stuff I do lent itself fairly well to that. More field-oriented people, it was a struggle. I certainly had colleagues going out with drones, and trying to do virtual field trips, and get YouTube videos together. But it worked OK on my end of things.

ZIERLER: For your own research, it was a pretty easy transition in terms of being able to do things remotely?

BOYCE: Yeah. I just brought a bunch of books home. I made a little side porch office off of our bedroom where I could actually get enough wireless signal to work, and I just sat on a chair for two years in the backyard.

ZIERLER: Kevin, we'll bring the story right up to the present. It's a year after; hopefully the end of COVID. You're no longer chair. What are you focused on these days?

BOYCE: I guess this came up right at the very beginning of the interview. I have been trying to do more worrying about the entirety of terrestrial systems. Marine is a step too far for me. I can't do that, but everything on my end on land, as far as worrying about how insects have evolved, and worrying about the long-term carbon cycle. In, the years since I've moved to Stanford, I've really put a lot of effort in trying to learn the parallel literatures and the parallel disciplines within paleontology and knowing what's going on in modern soils, and just thinking about how to bridge that, because the subdisciplines are very siloed. Paleobotanists don't know vertebrates. [laugh] They know there are dinosaurs, and some of them may eat the plants, but you wouldn't learn both. People that know fossil insects just know fossil insects, etc., but all these components are interrelated. I've put a lot of effort into trying to learn those parallel records, and just how to put those records together, because I feel like there's a lot of science that's done wrong, like, conclusions are drawn and assumptions made that are wrong because people don't know these parallel records that could rule out the conclusions they are reaching. And there is also a lot of opportunity. I've always had faith that if you connect two things that don't have any current connection, something will come of that effort. This went back to, for me, this went back to when I was a postdoc. There was once a time where I flew someplace, and the instrument I was traveling to use broke while I was on the plane. I was stuck in D.C. for a week, with nothing to do. I found a book sitting in an empty conference room, on industrial wood pulping. [laugh] I don't know why it was there, but like, well, wood pulping, making paper, OK. I'm a paleobotanist, so we're both talking about plants. I bet if I'm the first paleobotanist to read a book on wood pulping, something will come of it—

ZIERLER: [laugh]

BOYCE: —and it did. It was actually one of my highest-cited papers, where there's all this detail about the plants in the wood pulping stuff that's actually contradictory to what botanists think about the same tissues. Why do they have different opinions about this? Then trying to parse that out went someplace. Similarly I felt like, well, if I try to understand what is known about the long-term carbon cycle as a paleontologist, something will come of that. There's been a variety of projects built out of trying to learn all these parallel records.

ZIERLER: Is that to say that there's a convergence that you're asking almost bigger questions now?

BOYCE: Yeah. Did you bring up the word "geobiology"?

ZIERLER: Yeah.

BOYCE: When I was hired at Stanford, it was as a geobiologist, because that's what they were looking for. Whereas when I was at Chicago the emphasis was much more kind of internal looking within the fossil record. That's the wrong word. But the paleontological emphasis was more about asking questions about evolution, not the Earth system. Whereas I have tended to think more in an Earth system direction since coming here. I had already started worrying about climate, and how plants have driven change, before I had moved. But there's certainly much more of that on this end.

ZIERLER: Kevin, now that we've worked right up to the present, I want to ask a few retrospective questions about your career, and then we can end looking to the future. I'm always interested in the sociology of science, the professional affiliation, so for you: Botanical Society of America, Geological Society of America, International Organization of Paleobotany, Paleontological Society. What among them, or if it's all of them, is substantively most important, not just that it's nice to be a member but this is actually an important place for you to meet people and do the research that you do?

BOYCE: The Paleo Society meets at the geology meeting, so those are in some ways the same thing. That's actually a more insightful qu…it never would've occurred to me to ask that question, but there is substance to that.

ZIERLER: That's what I hope for. [laugh]

BOYCE: There's a weird dichotomy in paleobotany, where there's paleobotany at the botany meetings, and there's paleobotany at the geology meetings, the Paleo Society meetings, but they're very different kinds of paleobotany. Typically, people only go to one or the other, and there are BSA paleobotanists, and there are GSA paleobotanists, and they're different people. Throughout, certainly, when I was coming up as an assistant professor, I always tried to go to both, and I was the one person that I could think of that was routinely doing that. A little of that might've been strategic in the sense that I figured that I'd have letter writers coming from both ends of that for tenure, so they should both know who I am. But also just scientifically, the botany side of things was more geared towards the anatomy, and how do you describe this as a fossil, and the taxonomy. Whereas the geology side was more paleoecology and environments. But they're both relevant. Those two are like the home institutions. These days, I tend to go more to the geology than the botany, but that's almost more about the scheduling convenience of the time of year.

ZIERLER: Kevin, the students that you've had over the years, graduate students, postdocs, obviously your focus is so fundamental. It's basic science oriented. Are there skills that students in your group pick up that if they want, they are relevant and valuable in industry?

BOYCE: It's up to the student. I've never had a big lab, so it's not like I have a huge data set of, you know, where I can say "Out of my 80 students…" [laugh]—that's not what my life is like at all. It's always a small group of, at most, two or three students. Certainly, I'm interested in the skills they bring to it, and I hope that they know something that I don't, from the beginning. I like it when my students are a geology major because I wasn't a geology major, and so they have skills I don't have. I've had a student that came with a solid footing in insects, which I did not have at all, and it was a chance to learn more about insects. There isn't necessarily a shared focus across students. But I think what I try to instill is some kind of, like, making sure to think through the implications aspect of it all. You have this fossil. How did it grow? How did it work? How did it interact with the world? Then how do those things feed back on each other, and just a thoroughness to it. I guess a way to think about it is that what I try to emphasize is: what are the things you believe that are actually mutually contradictory if you think it through, and then what do you do with that?

ZIERLER: To stay on the theme of fundamental research, what about applications? I know that's not your focus, but is there an afterlife of your research? For example, you mentioned climate change. Where do we see the things that you're looking at that are relevant in the here and now?

BOYCE: For me, the here and now had to come from someplace. I think that if you think only over timescales of your own lifespan, you're going to get it wrong. Humans barely bump up against some of the longer term aspects of how the world works. One thing that I like to go through when I teach is I use Herodotus in the context of Hurricane Katrina. When Hurricane Katrina happened, the big response at the time was, who could have guessed this would happen? The answer is, well, Herodotus would've guessed, because he had access to the Egyptian records including several thousand years of records of Nile floods, and they totally understood the importance of floods and sediment delivery and building up of the land over that time. If you turn off the sediment deposition, as with the Mississippi, you end up with a New Orleans under sea level, and Katrina happens.

The problem is that we're a young society, and we don't have any kind of bearing for more than, you know, even 100 years is hard for us. It was easier for the Egyptians because they were thinking in terms of the centuries. I think a lot really does have to come down to understanding that we are a blip in a larger continuum of how things have happened. I'm not going to tell you the best way to get the anthropogenic CO2 out of the sky, that application side of it. If someone finds applications in my work, that would make me very happy. But I'm more interested in understanding. You can't save the Earth if you don't understand it, and we really don't understand it. A lot of that comes down to not this moment, but understanding that this planet is a four-and-a-half-billion-year-old experiment where there's a lot larger range of things that have happened than what you saw at the mall last month or whatever.

ZIERLER: [laugh]

BOYCE: I think that is essential for any of that stuff, for any of the future, but it's understanding how we got there in the first place.

ZIERLER: Kevin, of course, what brings us together is you're a Caltech alumnus. I'm curious if you've ever thought about, you know, you went in a very different direction from biology and literature as an undergrad. Regardless, what has stayed with you from your Caltech days, learning how to be a scientist, working with colleagues, your approach to complex questions? What continues to inform how you see the world?

BOYCE: [laugh] I got into Caltech on some basic level because of athletics, and I did an English major, and then I went into paleontology.

ZIERLER: [laugh]

BOYCE: None of that screams Caltech. [laugh]

ZIERLER: [laugh]

BOYCE: But Tech is very fundamental to it all. Just both the opportunities I had to make decisions early and to cast a wider net would not have happened if I had not worked in a lab as early as I did. I think it's unusual to be doing that so early at places other than Caltech. A lot of just the culture of that place, and there's a common, I mean, it's almost a sense of humor, and just a perspective on the world that made me feel very much at home as an undergrad, and the way people interacted with each other that I very much appreciated. I feel like, even if I haven't used the facts, the education I got is really central to everything. The big educational dichotomy is always liberal arts versus a big university. And with a liberal arts college, the emphasis is always that that's where you get the better teaching, because that is a more central mission of the faculty.

Whatever would've been different as far as the classes in the liberal arts setting, I can't know because I went to Caltech. But I felt like I had good classes. And part of what really mattered to me when I was an undergrad was how frequently, you know, "Oh look, there's the professor in the textbook," and just how these are the people that are actually doing the stuff that it is in the textbook. Really, I think it grounds you as far as what do I want to add? What do I want to do? But it very much makes you feel like you've got to do something. You're not learning something; you're preparing to do something. You're not a biology major; you're a biologist. Go do it. That aspect of it all, and just go figure it out. Even if the things I went to go figure out aren't necessarily much covered in the curriculum at Caltech, Tech was very central to that.

ZIERLER: Kevin, I asked about the dogmas that you encountered as a graduate student, and you referred me back to a scientific tradition that goes back to the Victorian era. On a shorter timescale, from the beginning of your research career till now, how have those dogmas changed, and what do you see as your contributions?

BOYCE: It is interesting getting older in science, because there are things that I would do 15 years ago, where I would know who I was arguing with, like, which older colleague.

ZIERLER: [laugh]

BOYCE: Now that they're retired, I've no one to argue with. Right now, people can argue with me. It's a weird transition in academic ontogeny, where now I'm 50, and most of the people I was arguing with when I was a grad student, they're retired now. I'm sorry, how did you phrase the question? [laugh]

ZIERLER: When you're young as a graduate student, you're thinking about the giants in the field, the big dogmas, and pushing up against them. How have they changed now that you're on the other side of an academic career?

BOYCE: I feel like it's interesting in paleontology, because a lot of the arguments are very slow motion in that sense that you're arguing with a paper that may have come out 5 or 10 years ago, and then someone will argue with you 5 years later. The impact is real, but it's not as large a field, so the conversation gets parsed out over more time. In part, that's a lot of the appeal, the fact that anything I do, maybe no one else would've done. Whereas there's lots of fields where it's much more saturated with people, and you know if you don't do it, someone else is going to do it six months later. I like that openness of paleontology, but it does slow down the way these interactions occur. But I do feel like I've tried to bring a perspective of, this fossil isn't just a rock, it was alive. It was an organism. Let's think about it as an organism. It's like this fun little puzzle. There is an organism in this box. We can't get it out of the box, but there's an organism in there. What can we learn about that organism, despite the fact that it's in a box? That approach to being a modern biologist working with something that's been dead for hundreds of millions of years, I feel like that has become more common in recent years. So it's been fun to be a part of that.

ZIERLER: Kevin, we'll end looking to the future, the very, very distant future, and this again will bump up as much into philosophy as anything else. You've emphasized that humanity, we're a blip. If the Anthropocene—if that's the right word—it's not going to be around forever, 100 years, 10,000 years, whatever it is, in the grand sweep of geological history, you're looking 540 million years into the past, let's look 540 million years into the future. What would be the impact of looking at this blip in time on what the humans have done to the Earth as a paleobiological question?

BOYCE: You bring up the Anthropocene. It's interesting to think about those things. This came up when I was a grad student, actually. There was some older—and I don't remember which professor it was—but some professor brought up their own oral exam when they were a grad student. They were asked the question—so this would've been back in the '70s, probably—going 100 million years in the future, what would be the visible impact of humans? The correct answer at that time was, there would be none [laugh], because geology operates on longer timescales. That's been a huge sea change of now people do emphasize how much we've changed the planet, and how much we've hijacked various elemental cycles, and what it would look like as far as a mass extinction. That's all true. We have done all those things.

But when you ask, what will we look like from the future, it's still an in-between thing. I'm perfectly happy to see the Anthropocene not happen as a chunk of the geologic timescale because, going forward 100 million years, it will be too short to define. We're in the Holocene now, which is just 12,000 years. That's too short. [laugh] We only define an interval that short because we're in it. In the distant geologic future, they won't be able to recognize that sliver of time as distinct. If you go forward that far in the future, we will definitely see that we've changed the world, and geochemically in all these ways we do matter. But we will—when I say "we," I mean the future paleontologists, with all of their antennae and whatever they may have that far in the future, when they try to look at what humans did back now, they will underestimate what we did, because they will not have the time resolution to realize that we messed things up and changed things so much that quickly, because you would only be able to measure it probably in increments of 10,000 years. All of the change in the last century would have to be averaged over 10,000 years, so there wouldn't even be a recognition of how quickly we changed stuff. I find that to be an interesting thing to think about.

ZIERLER: Just as an addendum, you're saying this with the understanding that obviously there would be advances in instrumentation for greater sensitivity that they would have, and yet you're still saying that they would miss the bigger picture?

BOYCE: Yeah, because you can't change time averaging of rocks. The way the rock record works is that sediment particles get reworked. There are individual beds where you can pick things up. The rock record itself, an individual bed might be, you know, one good storm is a bed. But the way you end up looking at things, most time isn't represented. Most of the time, it's in between the beds of sediment, and not the beds of sediment themselves. Over an outcrop or something like that, you're looking at a fair amount of time with most of that time missing or mixed up and averaged together. It's not about instrument sensitivity, right, that's going to give you needing that many fewer atoms to get an analytical result…you know, that kind of sensitivity. But you can't change the way the rock record works and that degree of time averaging. What we've done in a century will probably be—you wouldn't be able to measure it in less than increments of at least millennia, probably tens of thousands of years.

ZIERLER: That doesn't mean that we're off the hook, though, even if they can't see it? [laugh]

BOYCE: Nope, but they will not realize how badly [laugh] we changed things and how quickly, because their denominator will be 10,000 years instead of a century.

ZIERLER: Kevin, this has been an awesome conversation. I want to thank you so much for spending the time.

BOYCE: Thank you for having me. I really appreciate that this exists.

[END]