The Stanford paleobotanist and 2013 MacArthur Fellow answers a few questions about his work, and what a 100-million-year-old leaf can tell us about the world today.
CAA: What is a Paleobotanist?
Boyce: Very different people work on the front line of fossil records. Some analyze vertebrates, such as dinosaurs. Paleobotanists like me study how plants are formed. Taken together, all of our work creates a picture of Earth’s environment from a different time.
CAA: How did you choose this line of work?
Boyce: What I do isn’t the type of biology pursued at Caltech, but it was important for me to be there. I studied cell morphology in Eric Davidson’s lab and Joe Kirschvink in geobiology helped to spark my interest in Earth’s biodiversity. I also majored in literature. George Pigman’s classes on Chaucer interested me in historical texts—which are similar to fossils, in a way.
I'd be perfectly happy being a biblical scholar if I wasn’t so terrible with foreign language. Reading someone like Chaucer, it's very easy to think you understand the text by projecting our modern world back on to it. Then you'll get to something that you just can't understand from a modern perspective—and you can't justify it away. That’s also true with fossils. There were forests 350 million years ago. They may feel familiar on a first look, but they were fundamentally different.
CAA: How do you approach your work with fossils?
Boyce: Any examination of fossil records has to start with our understanding of modern ecology. You look at a fossil of a leaf and think, “Okay, that looks like a leaf. I understand that.” But as you examine the details more closely—and plant fossils can offer a great deal of detail, down to cellular anatomy—you discover that there are a number of differences within the structure. This leaf may not, in fact, operate like leaves today in terms of its construction or biological processes.
CAA: What does a prehistoric plant look like?
Boyce: There's a lot of weird things out there, like Lepidodendron. Their closest relative today are these scruffy little plants a couple inches tall that poke their heads out of leaf litter in temperate forests. But if you went back 300 million years, they were the canopy trees — 30, 40 meters tall. They weren’t constructed at all like today’s trees, though. They had almost no wood at all, just a great deal of bark. It's unclear what was holding them up. Everything about their construction is very strange.
CAA: What significant changes have occurred in plant life?
Boyce: Today, most plants are flowering plants, with reproductive characteristics that typically include flowers, seeds, or fruit. But more than 100 million years ago, these types of plants didn’t exist. So how is it that they came to take over? Through my work, I demonstrated that as temperatures rose at that time, flowering plants’ evolved a high vein density which allowed them to cycle water at faster rates than previously dominant plants.
CAA: What can these plants teach us about today’s ecology?
Boyce: They can help us understand the origins of our food supply—which is dominated by crops that are all basically flowering plants.
One focus of my research is how primary production, the process by which living compounds are synthesized from carbon dioxide, has changed over time. We know that today, carbon dioxide is increasing in the atmosphere. Generally, if you give plants more carbon dioxide, they’ll perform more photosynthesis and grow faster. That effect is easy to study over a couple of years. But what would happen if you were looking at increased levels of carbon dioxide across very large scales and over revolutionary time periods?
Understanding how past ecologies adapted and changed may yield us valuable clues into our ecology today. And—presented with new changes to the environment, how it might adapt again.