Jonah: I’m Jonah Chester.
Clay: I’m Clay Catlin and you’re listening to Animal/Human.
Jonah: This show is a production of IU’s College of Arts and Sciences and a proud part of the 2018 Themester.
Clay: Each episode, we talk with a different IU researcher to examine where we, as humans, belong in the animal kingdom.
Jonah: We also examine the interactions of humans and animals in art, literature and science.
Clay: In this episode, Jonah sits down with Dr. Michael Wasserman, a professor in the Anthropology department.
Jonah: Dr. Wasserman’s work focuses on how primate diets influence their behavior. He’s done work throughout Africa, including in Kibala National Park in Uganda.
Clay: Dr. Wasserman’s work investigating primate diets also helps reveal our own roots and how our past diets influenced our development from early hominids into who we are today.
Dr. Wasserman: I’m Mike Wasserman. I'm an assistant professor in anthropology and human biology and I’m finishing my second year here at IU. In addition to teaching in anthropology and human biology, I’m also developing, setting up, and now running the PEEL (Primate Environmental Endocrinology Lab). That involves looking at various analyses to understand primate hormone levels and chemistry and the interaction between the two.
Jonah: Can you tell me a little bit more about the PEEL Lab? What’s some of the hands-on, practical work you’re doing with that?
Dr. Wasserman: So I started the PEEL lab two years ago and brought in a number of graduate and undergraduate students along with some other staff. The main goal is to look at how various environmental factors influence primate biology. Specifically in terms of their physiology, behaviours, and their population status for a number of different species across the tropics. We’re really interested in how these environmental factors get biologically embedded in these primates as mediated by the endocrine system. So understanding things like how does predation affect primates, how does diet affect primates, and how does human activity affect primates. Not directly, through things like mortality. Obviously predation would affect that, we’re more interested in the long-term or subtle effects of these environmental factors. How it affects stress levels and reproduction, things like that. For instance, I’ve had a long-term interest in chronic stress and its effects on primates (including humans). [Specifically studying] elevated cortisol levels. [Cortisol is] a hormone produced by the adrenal gland that's often considered an index of stress. When you have this constantly elevated level of cortisol response and stress in general, it can affect other systems in the body. So It can cause the immune system to be suppressed, it can cause reproduction to be suppressed, it can have long term health effects on things like cardiovascular disease, type two diabetes and so on.
Jonah: So that’s in primates but it’s also found in humans as well. So in your research, you look at apes to figure out how these factors would affect humans as well. Am I surmising that correctly?
Dr. Wasserman: Yeah, so that’s come in more recently in my career. I started off being very interested in conservation of tropical forest and studying monkeys apes and so on. The more I studied the monkeys the more I became interested in human medical literature in terms of how can we use long term studies of apes and monkeys in their natural environments to give us a little more context in terms of the ecology and evolution of our own diseases. So yes that's definitely something I’ve been interested in more recently.
Jonah: Can you tell me a little about the class you’re teaching for the Themester? It’s Hormones and Human Behavior.
Dr. Wasserman: Yeah, so this is an upper-level class that brings in about 25 students. What I do with the class is kind of use my framework... in ecology and evolution and environmental issues surrounding human activity. And so we do a lot of work with that kind of stress. [We look at] how the endocrine system mediates dealing with stressors in the environment through the production of cortisol and through what we call HP access.So we go through kind of the nuts and bolts of how the endocrine system works and then we focus more on the adaptive significance of that system. So how does it help a monkey living in the forest deal with predators trying to attack and consume it? Or how does it help deal with logging and deforestation for people living in that environment. A good chunk of the class is looking at chronic stress relating to a bunch of different factors. Then we also look at reproduction and things that can influence and surpress that, including endocrine disruptors. [Endocrine disruptors are] things in the environment that mimic hormones when they get into the body, they either block hormone action or increase it.
Jonah: Are there any particularly notorious environmental chemicals that will do that?
Dr. Wasserman: So for the PEEL lab and my research, we’re more focused on the naturally occurring endocrine disruptors. So these are plant compounds that mimic estrogen and progesterone. So that's what we’re looking at. We’re also getting into synthetic endocrine disruptors and starting to look at pollution in primate environments. Things like BPA and these plastics that can leach into food, get into a body, and cause problems because they mimic estrogen and other hormones. So we’re not looking at BPA but we are looking at pesticides. So pesticides are definitely an issue because pretty much around the world you may have a national park that’s protected and in this pristine state. But around the park is often agriculture and with agriculture you get a lot of use of pesticides. Especially in the tropics, you get a lot of these pesticides because there’s so many fungi and insect species you have to deal with. So we’re looking at pesticides and we’re also looking at flame retardants as well. So these are just in general applied on consumer goods. And so they're actually a nice index of human activity. Because somewhere where you have a lot of human developments, you also have a lot of consumer goods. [Because of that,] a lot of these flame retardants can get into the environment and we can measure those to look at human presence across a variety of different locations.
Jonah: One of the other courses you teach is Evolution of the Human Ecological Footprint . It examines, “A series of threshold moments in the history of our species that had great implications for the environment.” What are these threshold moments?
Dr. Wasserman: This course came out of my experience as a grad student. I was TAing a human diet course which really focused on the evolution of human diet. [Because of] my interest in conservation and environmental issues, I was thinking it would be really cool to take this human diet course and kind of switch the perspective so we're not looking at the human species and how we’re affected by these threshold moments, but how our changes affected the other species on earth. Those threshold moments, and I wouldn’t say they’re on specific moment in time--
Jonah: So they’re not a clean cut moment?
Dr. Wasserman: Exactly, so you have this kind of general timeframe when you get some kind of major shifts that occur over maybe a few hundred or thousand years. Those changes result in major shifts in the way biodiversity looks on earth and the way climate systems operate. And so those threshold moments include the origin of our species and the megafaunal collapse. This was a time period when a lot of large mammals went extinct, which was due to climate change and human activity. That results in broad spectrum evolution when our diets evolved from consuming those large species to consuming many smaller species found in the environment. So we get a lot of diversity in diet and in what we’re consuming during that broad spectrum revolution. And then we have a shift towards agriculture. So the origins of agriculture are a big threshold moment. As we move through time with agriculture, eventually you get urbanization. City centers start forming and then you get colonization and globalization as a result of this long distance interaction of human populations and humans affecting environments in far off places. And then you get the industrial revolution and the green revolution with diet. So this system of growing and increasing productivity of our crops through high input systems using a lot of water and pesticides, fertilizers, and fossil fuels. From that you get the great acceleration. That's really the last really major threshold moment. [It] is currently considered by some as the start of the anthropocene, where human activity has now come to dominate the landscape. And so that great acceleration occurred right around the end of WW2. You see, across a bunch of different measures, this growth in human consumption of resource from that time period until today. As a result, we see biodiversity loss, climate change, putrification of water systems and a number of environmental issues we see today.
Jonah: How do you predict our diets today changing in the future and how will that impact our evolution further in the coming centuries and millennia?
Dr. Wasserman: First of all, I think when we talk about evolution, there’s biological evolution that depend on genetic changes in evolution and we have cultural evolution, or shifts in the tools and tech used to meet goals. A lot of the changes we've seen over our history, especially since the origins of agriculture, have been cultural. There really hasn’t been a lot of biological changes as a result of diet. We do have some; for instance, people who have the ability to digest lactase into adulthood while most people can't do that. But there’s not a whole lot of biological change. So thinking about the future through culture, what I would say [is] a really interesting, difficult question to answer...has something to do with the homogeneity of our diets that's occurred. So if we shifted back from how human diet has changed from our origins to today, the general trend we see is a great loss of diversity in our diets. To the point that today we get almost 50% of our calories globally from three crops; wheat, rice, and corn. If you add three more crops you get up to 80% of our calories, if you go up to 14 crops you get 90% of calories. And so we’ve had this loss of diversity within our own diets over time to go along with loss of biodiversity. I’d say in terms of future evolution, it’ll probably be something to do with our interactions with those crops that we’re highly dependent on.
Jonah: So, is that loss of diversity and crops necessarily a bad thing? Or is it just sort of an adaptive thing; we chose these couple of crops because they're easy to grow and its convenient and takes less input and resources. Will that turn out to be a negative thing or is it just different from the way things have been in the past?
Dr. Wasserman ; So, I don’t like to use “is it a good thing or bad thing,” I prefer to view at as cost versus benefit. And I think what’s dangerous, what’s risky is this whole idea of putting all our eggs in one basket. Especially in an environment that's changin. It's not just that we’re dependent on these crops, we actually have lost a lot of these varieties of these crops as well, which is a great reduction in the genetic diversity of our crops. Sure that can mean its a simplified system, but with any loss of diversity, especially in the face of environmental change, there are fewer ways for those organisms to deal with those changes. What I mean is you often have an issue when you have a crop that has little genetic diversity and a pest comes in that can sweep through the population because there’s no genetic variation for it to handle that pest. And so I would be most concerned with that. We might be setting ourselves up for food shortage issues if there's a shift in environment and pests.
Jonah: It’s very similar to the film Interstellar. There’s like a disease that wipes out all of the world’s corn and it basically causes humanity to starve because that was one of the few crops they came to rely on.
Dr. Wasserman: That’s a great hollywood example. If you have more diversity in your food system, it's going to be more resistant to potential threats.
Jonah: So you would recommend that we do diversify our crops, despite the fact it may be a high level of input. The reward far outweighs the risk.
Dr. Wasserman: Yes, I definitely think that. I think diversifying our food crops, protecting biodiversity of wild species, and having agricultural systems that are agro-ecological systems is only going to help.
Jonah: And you also, in addition to researching the diets of humans and our evolution, you research the diets of apes. How has their diet evolved over the last couple centuries as we move into the anthropocene and move into their environment? Are we impacting what they eat?
Dr. Wasserman: I’ll use one example that is most well known to me and that I’ve seen. We have planted eucalyptus, which is from australia. We've planted it all over the world bc it’s good for draining swamps and it grows fast and it’s a good source of food. So it's been beneficial and we’ve planted it in many places. In Uganda, around the national park, it's been planted as well. And what happens is, because eucalyptus is very high in sodium and sodium is a limited nutrient in tropical forests, primates will leave the forest, the protected area, and they’ll go binge on the eucalyptus for a couple days. So, I've studied Red Colobus monkeys the most, and I’ve seen them do this every few weeks. They have this path they follow through the forest. So that’s one major shift we’ve seen in their diet. It’s also been seen in a number of other primate species.
Jonah: So, by influencing what they’re eating now, we’re influencing how they’ll change? Because I know you said in the course of change of human diets, our [evolutions have] been cultural. For the apes, are we actively influencing how they evolve by planting these non-native species?
Dr. Wasserman: So the question of evolution is tricky. It depends on [if] they’re going to be able to keep up with biological evolution, is it going to occur fast enough to occur with the environmental change? Because often, you know, you need mutations to occur. Most mutations are neutral or costly. So it's rare for a beneficial mutations to come about. It's possible, but what I'd say is more likely is that we change their physiology and behavior. It's hard to predict what will happen in the future, if they’ll be able to adapt. Sometimes, maybe, there's some beneficial changes that will occur from giving them easy access to limited nutrients. But [it’s] not just nutrients in plants foods, there are chemicals that come along with that. That chemistry can have negative effects on their physiology and behaviour.So, for example, in the study we did with the Red Colobus monkeys, we found three main food items that were estrogenic. A fig (which is native), a legume (which is native), but then eucalyptus. We don’t have data to say that's negatively impacting them yet, but if there were a situation were there was too much introduced, we could have negative physiological effects due to over consuming new chemicals.
Jonah: So, as the human population continues to rise, how do you imagine 100, 200 years from now, as we begin to move into the spaces that were once empty, that were these primates habitat, how do you predict their diet will change accordingly?
Dr. Wasserman: I think what you’re going to see, what we’re seeing now, is more and more crop raiding. So the primates and other wildlife are moving into farm fields to look for nutrients and get nutrients from the crops. Not only is that changing their diet, but they’re also being exposed to pesticides. Their diets are shifting as they respond to human disturbance. Not only are their diets changing, but their exposure to chemicals, in addition to what's found in the food, is also a novel disturbance to their physiology.
Jonah: And then same question, I suppose, but how will our growth as a species affect human diets?
Dr. Wasserman: As our population increases, we already have issue with availability of meat. The most common nutrient deficiency in humans today is anemia as a result of a lack of meat consumption. If you look at data from studies around Africa, you have not only loss of biomass of wild species from bushmeat hunting, you also have loss of fisheries. I think our biggest dietary problem will be how to continue to meet protein and iron needs of the human population as we're losing biomass and wild species, which a lot of people depend on for protein. Probably you’re going to see more and more vegetarian diets. Not necessarily 100% vegetarian, but less dependence on meat and more dependence on plants and even insects to meet dietary needs.
Jonah: Before I let you go, is there anything else you want to share with our listeners?
Dr. Wasserman: I would just end by saying diet, as everyone is aware, is critically important. Diet isn’t just the nutrients you need to meet your biological needs, it's also the other chemicals you find in foods. I think we all need to think more about what we’re consuming and how we produce what we’re consuming and what that's doing for not just our health, but for the health of the entire planet. In order for us to have sustainable wild systems and forests around the world, but also for us to have healthy lives and live sustainably as a species.
Clay: This show has been a project of the Indiana University College of Arts and Sciences Themester.
Jonah: Thank you to our guest for this episode, Dr. Wasserman, for talking with me.
Clay: Editing, hosting, and mixing for this episode was provided by Jonah.
Jonah: On the next, and final episode, Clay sits down with Dr. Jeanne Sept. They’re going to talk about how we became who we are today.
Clay: That’s how we made our transition from being the animals we once were to the humans that we are to do, tracing our ancestry through the early hominid species.
Jonah: Thanks for listening, and we’ll see you next time.