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Posted on May 4, 2017 - 4:18pm
Written by Colton Smith
On April 5, 2017 I had the opportunity to sit down and speak with Dr. Zachary Adam. Dr. Adam is a Simons Foundation Postdoctoral Fellow at Harvard University in the Department of Earth and Planetary Sciences and the Harvard Origins Initiative. His research focuses on the broad theme of “Physicochemical automata and life’s origins.” He was brought to ASU as the recipient of the 2017 Origins Project Postdoctoral Lectureship Award and to give several lectures to the public on the research being done to understand the origins of life.
The conversation that we had focused on the type of research that he’s currently involved in and the events that led him to this point.
Colton Smith: Hello Dr. Adam, thank you for taking the time to meet with me today.
Zachary Adam: It’s my pleasure. Thank you for taking the time as well.
Smith: So I want to begin by asking you a couple questions about the events that led you to this point in your life. Not only are you working at one of the most prestigious universities in the world, but you’re also working on one of the most fascinating research questions of all time; the origins of life. Obviously this is no simple feat. Where did your journey begin?
Adam: I suppose you could say that my journey began when I was working on my PhD at Montana State University. There I frequently traveled to the mountains of Montana to study billion-year-old fossilized microorganisms. I worked for a long time excavating these fossils from the Belt Supergroup in the mountains.
Smith: Within the Belt Supergroup you found these fossils? I work in a neurobiology lab so I have no conception of what it is you do. So you would venture into these mountains to find these?
Adam: Yes. There are very few places around the world where you can find billion and a half year old rocks, let alone rocks with fossils in them. So when I went to Montana State I had to pick and design a project with my advisors and I figured that some these rocks are only about an hour away from Bozeman so I could be out there as much as I wanted and gain a lot of field experience. I would go out to these rocks every weekend and try to find tiny, millimeter-thick layers of rock that have fossils in them. Theoretically, if they’re eukaryotes, they could be some of our oldest ancestors. These organisms would’ve jumped the divide between simple single-celled organisms to complex multi-cellular organisms like trees, frogs, fungi, and even people.
Smith: So you were attempting to understand the transitionary period between simple life forms and complex life forms and how life started in general. Is that what you’re working on now?
Adam: Yeah! And even though they are totally different concepts, they describe the same basic phenomenon. Basically you have simple parts interacting with each other and combining to take on the characteristics of a larger aggregate that behaves fundamentally different. Let’s construct an example that involves you and I sitting in this office. This office is part of a university, which is part of a city, which is part of a state, which is part of a country, which is on a planet. And if we met under different circumstances, let’s say outside of the university, we may behave fundamentally differently because we don’t have these associations with these larger organizations.
Smith: It’s almost as if this university is a cell and you and I are proteins that interact within a larger scope
Smith: My next question stems purely from curiosity. My naïve perception of all Paleontologists is that they are researchers who dig in the ground and find bones. I can even imagine you out in the field with a little tool kit that helps you find dinosaur bones [laughing]. But I can imagine the types of organisms you’re looking for can be quite small. What kind of organisms were you looking for and how big were they?
Adam: The field of micropaleontology literally means the study of microscopic fossils. To see these fossils you literally need a microscope. Along that same thread that we just mentioned, microbes interact with each other to form communities. They exchange nutrients with each other and fight each other in similar ways that humans do and make cities out of microbial mats. These mats can shape the way that sediment gets deposited and you can see that with the naked eye.
Smith: So when you’re out in the field you can actually determine what areas of rock would most likely have microfossils in it just based on the appearance of the rocks?
Adam: Exactly. And the fact that I only lived a couple hours away from this site, as opposed to halfway across the world, means I could take samples back to my lab and within an hour quickly determine if I have well-preserved microfossils. If I don’t find high quality fossils I can quickly go back to the sediment and try to sample a new area. It really comes down to that scale of resolution to find something incredibly well preserved.
Smith: It must’ve been really convenient to have your laboratory right next where you gather your data. I’m sure most people don’t have that convenience.
Adam: Part of that too was the reverse of that. As geologists we really love to go to these really exotic places. I would love to see Antarctica and scout it for microfossils. But what I really love about this field is that most people don’t know that they are overlooking what’s in their backyard. The reason I focused on this area was that it was nearby in a small farming community. It was really amazing to go back to this farming community and tell them about this incredible treasure of fossils that is right in their backyard.
Smith: How did you find this treasure trove of microfossils? Was this an area that's known to the scientific community?
Adam: So the deeper story is that when Darwin wrote about evolution in [On the] Origin of Species he had a huge problem. Fossils showed up in the Cambrian and after that there was a pretty good record of change over time, but before the Cambrian it’s like all of these fossils just showed up out of nowhere.
Smith: Fossils popping out of nowhere doesn’t sound very conducive to Darwin’s Theory of Evolution.
Adam: [Laughing] Exactly. And that was a huge dilemma. There were a couple places around the world where people suspected there were old rocks, but they didn't have the proper dating techniques to confirm anything. Also, the fossils were buried underneath younger rocks. But now we know about we can find the fossils more easily. As I mentioned before some traces can be seen by the naked eye. Actually one of the types of rocks that I worked with extensively looked as if a child had come and drawn on the surfaces of the rocks.
Smith: But these patterns were obviously non man-made.
Adam: And geological processes couldn’t explain them.
Smith: Naturally that indicates some sort of biological reaction.
Adam: This was actually described by Charles Walcott back in the day. He was a really influential man who wrote about these rock patterns, but everyone dismissed it. They thought that since it wasn’t a bone or a piece of a tree then it wasn’t to be preserved. So many people thought that these formations weren’t fossils and dismissed Charles’ idea.
Smith: I suppose you really can’t blame them for thinking that, considering the techniques for analyzing microscopic material wasn’t as advanced as it is today.
Adam: Very true. And so fast-forward about 50-60 years people gradually accepted that there were actually traces of life before the Cambrian. At Glacier National Park in Montana there are actually these beautiful stromatolites, microbial communities growing one on top of the other, that were discovered by a man named Bob Horodyski. Unfortunately the microfossils found in these rocks weren’t well preserved and so they were overlooked for a long time.
Smith: It sounds like the scientific community determined that Montana wasn’t a good place to find well-preserved microfossils.
Adam: Exactly. Bob spent many years there and didn't really find much. After he passed away unexpectedly a man named Nick Butterfield working at Cambridge at the time made an extraordinary discovery. The researchers were destroying the fossils in the process of looking for them!
Smith: Wow it was man-made deterioration of the microfossils?
Adam: Yes! Researchers used to take these rocks, shake them up, and boil them in acid. All of this is very vigorous on these delicate little fossils. So it was the process of taking them from the field and trying to extract them that was destroying them.
Smith: Obviously the way you handle specimens is important for scientific analysis, but did anyone in the field at the time speculate that it was the extraction process that was damaging the microfossils?
Adam: A lot of scientific inquiry has to do with the fact that you have to build on what came before you and sometimes you pick up the presumptions of the people working before us. A lot of the time we don’t even think about it. So the techniques that were adapted to look for microfossils actually came from the process of looking for spores of trees in lake sediments. A while back someone thought that it would be a good idea to use this method to look for older fossils.
Smith: So micro-paleontologists just took the tried and true spore technique into their realm? [Laughing]
Adam: It’s just one of those really simple things that while you’re toiling away in the lab for many years you suddenly realize that you could make some slight change in a procedure that may open up more possibilities. And that’s exactly what happened. Sometimes we just have blinders that we accept to get through the day that, once modified, open up new possibilities.
Smith: The reason I find that story so fascinating is that is clearly exemplifies a common process in science. Scientists take the techniques of their predecessors and work with it for years and years until we realize that things could be done better. That’s exactly how new techniques and innovations happen. What people don’t realize about us scientists is that, although we’re a pretty smart bunch of people, it’s ultimately about sitting down and working with something for so long until you start to notice things.
Adam: As a student learning these techniques we are very indebted to inheriting this kind of information.
Smith: I guess we can fast forward now since that was the work for your PhD project. How did end up working in at the Harvard lab that you are currently at? It doesn’t sound like you’re working in exactly the same field that you used to be.
Adam: I’m actually working in the prebiotic chemistry now and that’s what’s brought me here to ASU to talk about the origins of life. In the same respect I see the origins of life, the emergence of life forms from chemical predecessors, as being almost a conceptual parallel to the origins of eukaryotes from bacterial predecessors. I work at Harvard as part of an international collaborative effort between Harvard University and ELSI at the Tokyo Institute of Technology. The group has been charged with a couple of projects and one of those is to try and reconstruct the origins of life and to vigorously construct and conduct experiments that might provide insight onto how life originated on our planet.
Smith: That’s fascinating. This is not only one of the most important questions in science but also one of the most difficult to tackle. It’s logical that at some point we had inorganic material and then we had organic material and there had to have been a transition between these two states. I can’t even imagine what sort of techniques and approaches you would have to take to determine what that transition was. The first thought that comes to my mind is that you would need to have a very large team consisting of chemists, biologists, physicists, astronomers, and geologists to be able to tackle this question. What is your job in this collaborative effort between Harvard and Japan?
Adam: So my job is to serve as the geologist. As you said, I work with astronomers on some days and I work with computer programmers on other days. I also work with organic chemists and inorganic chemists as well. A lot of what we do is just explain to each other the terms we’re using. The NASA Astrobiology institute has actually been at the forefront of setting the expectation and setting the template for how scientists interact with one another from different fields. They’ve pointed out time and time again that if you really want to make progress you need to be speaking the same language. You need to be able to understand what I mean when I say a specific technical term and also understand how it relates to your particular expertise. So most of the work that I do is providing an explanation or a set of testable hypotheses about certain chemical conditions and where they would occur. For example being able to know if life is possible at the beach, in the atmosphere, or perhaps even 13.7 miles underground. Sometimes it’s astounding but from my perspective as a geologist it can be really surprising when somebody comes to me with this really fascinating chemical process and my answer is “yeah that’s great but it could only possibly happen on Titan 100 kilometers up in the atmosphere and/or it could only happen at the bottom of an ice sheet at the bottom of Greenland over the period of a million years” [laughing]. So my job is to help the biologists and chemists understand what is it about those two environments that connect them together so that we may build experiments from there.
Smith: I have a question for you. Are the models that you have trying to determine what conditions were around in that abiotic environment that eventually spawned life? Where are you currently at with your models?
Adam: That’s a pretty broad ranging question [laughing]. That actually brings me back to why I’m here at ASU and what I’m excited about. I think we can look at the problem from an energetic perspective, a chemical perspective, and a logical perspective. Almost like programming. And I think the kind of change that’s going on in the field right now is that people are realizing that although we’ve made great progress in the past 20 years looking at all the variables individually, we need to start looking at how they interact together.
Smith: So would you say that the community has hashed out all of the individual variables pretty well? It sounds like you would need to have all these variables hashed out before you could even consider how they would interact with one another.
Adam: We’ve gotten as far as we can by looking at the pieces individually. I think we have a basic understanding of the rules of the road; which chemical compounds might be interesting, the bounding conditions for the early earth surface environment, and the radiation environment of the dust particles before they settled into planets. I think we have these big boxes to work in and the boxes are connected in different ways.
Smith: What are some of the individual variables in an early prebiotic earth that would be important for starting life?
Adam: I think we have a very good understanding of what energy sources were available at the time. We may not know exactly down to the exact decimal point how much was there, but we have a pretty good idea of what was available and a basic understanding of how these energy sources could relate to each other. And similarly I think we’ve got a reasonable expectation of the kind of chemical compounds that we can reasonably expect to have been around in abundance. This gets really difficult when we try and tie these things together. As you can imagine if you’ve got six different energy sources and twenty different compounds that the number of iterations and permutations quickly blows up. We’re trying to tie all these different fields of science together to answer this question. The purpose isn’t to get the right answer, but to instead rule out which options aren’t reasonable or and to produce the correct chemical outputs that would lead to life. So it’s more about focusing down our attention to the environments that are most likely to have led to life.
Smith: It sounds like you’re using science and logic to peer through the fog of the past and hone in on the truth. Realistically, what sorts of advances or discoveries do you believe the field will find within the next hundred years?
Adam: So I’ve got 100 years to work with? [Laughing]
Smith: Yes and for the purpose of this hypothetical scenario you also have unlimited funding. [Laughing].
Adam: I hope I’m not putting my foot in my mouth by making a prediction like this. One of the more surprising things that I think will be possible over a hundred years of time is that prebiotic research will have a very definite industrial application. I think that when we learn how to make a wide range of polymers under temperate conditions or learn to make a bunch of random polymers in the lab regularly over time that we will find solutions to chemical problems that aren’t found in biology. In Biology we all inherit the kind of genetic and metabolic capabilities of our ancestors. Every new organism that comes into existence doesn’t have the crazy mix of being able to eat uranium one day and eating an apple another. So that really means that biology is fixed in its ways and it takes a really long time to evolve a new fundamental capability that’s significantly different than what you’re inheriting.
Smith: Are you suggesting that we’ll be able to construct new forms of biology that can operate under fundamentally different principles?
Adam: Yes! If we can figure out how create new polymers, strings of compounds that have some catalytic or chemical capability, then we’ll find that we can explore new ways of synthesizing compounds that life hasn’t been encoded to produce. I think that we’ll find that we can connect these things in different non-biological ways that look like metabolic processes. Maybe the focus could be drawing down carbon dioxide from the atmosphere. You don't want to use organisms to do this since they’ve evolved to have a cell membrane that helps to ensure their own existence, but doesn’t really help in the context of drawing out CO2 from the atmosphere. Maybe we can get rid of some of those components at a really basic level and focus in on a set of interacting compounds that solely operate to remove CO2 from the atmosphere instead of using valuable metabolic energy for replicating itself.
Smith: The prospect of engineering compounds to work for us sounds fascinating. Instead of using organisms that evolved to fit specific environments we can construct new ones to fit our specific needs.
Adam: I think we’re right at the edge of that in many different ways and many different labs around the world are working on similar problems. We’re not looking at the origins of life with this objective in mind but I think it will be a natural application of this field. It might open up new possibilities for industrial chemistry that are derived and based on the rules of life but aren’t obligated to follow them.
Smith: Do your models take into account the possibility that life didn’t arise on this planet? For example perhaps an asteroid containing spores from space hit our planet and that was the origin of life on earth. Does that throw a wrench in the current models?
Adam: Not really. We’re interested in the fundamental process of the origins of life. If a spore of chemical complexity came to earth and propagated life we’ve just shifted the problem from being on earth to some other planet. The other more fundamental question with respect to all of the rocky planets that we’re finding outside of our solar system is if life didn't start on earth where did it happen and could it have happened on earth? And at a larger perspective how commonly does any life-forming process occur across the universe? How many of these planets that we know about have life on them? We’ve established the kind of playground for roughly how many planets we would expect to have habitable zones, but it’s still incumbent upon us to understand the process of life’s origins so that we can estimate how widespread various forms of life might be.
Smith: Let’s say we do find habitable planets that are within our reach, can you imagine a future where you’re suited up in an astronaut suit and sent to this planet to collect samples to test for life?
Adam: In the near-term I think we will have it within our capabilities to a send smaller spacecraft to go and collect high-resolution images. If we were given a longer time frame of a thousand years I’m intrigued by this idea that if we can create self-interacting chemical networks and we figure out how life started we would understand a basis for perpetuating a relatively small biosphere. So if we knew how to best shape and direct energy into the creation of organic compounds that can persist over a very long period of time we could start to think about the best way to start a new biosphere on Mars. Perhaps we can generate a geochemical bed of energy and compounds that can most efficiently make use of the capabilities of life and the materials on Mars to really kick start a new biosphere on Mars. Or in the longer term, getting to your question about getting to another planet or another stellar system that’s nearby, if we understand how life originates on any planet theoretically we my be able to shrink down that process to a mobile multigenerational spaceship. Because one of the big problems we can foresee in sending people to another stellar system is that if they bring energy and the genetic information and metabolic capabilities of earth they’re kind of locked in that sequence and we have to go to tremendous measures to ensure that that kind of bubble of life is going to make it. And we can’t lose significant amounts of biomass along the way. We basically have to recycle everything. And we have to account for the fact that along the way some things are going to die, some things are going to adapt and change, and we have to plan over a very long period of time. But if we remove the constraint that all biomass has to follow strict earth biological rules to survive the voyage there we can meld chemical computation and genetic memory to make the best use of all of the organic matter that we’re going to send to another star system. With that being said I think we can start to think about the system being inherently more resilient getting there. I think beyond 100 years to maybe a thousand years it will become feasible to engineer small biospheres to survive very long distances of travel.
Smith: Let’s explore a hypothetical scenario. Let’s say we get to Mars and we take samples from different regions around the planet and then we bring those samples back to you. Would you be able to analyze the material and determine if it contains microfossils? Has that already been attempted?
Adam: There are a number of labs around the world that are looking at the basic signatures of life. I think if there were biological traces there and we had some physical sample to look at there are many different ways that we can look at it. We can examine it at the fossil level and see if anything has been preserved.
Smith: I think that’s what people are very interested in. If you find a planet how do scientists go about determining if the planet ever harbored life?
Adam: If it was a really fine-grained material, like mud at the bottom of a lake or in a puddle, I would dissolve away most of the mud with acid and see if there are any preserved organic remains. I can also look at a special form of a rock called chert, which my boss worked with when he was a grad student. Basically in this kind of rock the fossil has been encased in glass. With this you shave away all of the rocks around it and look at it through a microscope to see if the shape of that glass left behind matches the shape of an organism. It’s a little bit different of a technique but it relies upon the same type of search pattern of trying to find shapes of organisms.
But we can go a level even deeper by looking at the molecular compounds that are there. This gets back to another use of prebiotic chemistry and space exploration. Now that we understand the kind of basic processes that we think were going on we can look at the chemical outputs of those non-biological processes and we can compare them to the chemical outputs of biological processes and say “well there are many ways to make organics but to make biological organics they have these attributes and if they’re just made by a volcano or lightning they are fundamentally different in the fact that they lack certain biological aspects.” Then we can compare and contrast them to determine whether material came from chemical processes vs. biological ones.
Smith: So let’s say we go to a planet to try and determine if life exists there or ever did exist there. Where do we look?
Adam: This is a really timely question because as we speak right now there are groups of scientists from around the world trying to determine where to send the next Mars rover. The rover Curiosity has been on the surface of Mars for many years and has established that the kind of geologic environment was more or less temperate at times and conducive to supporting life. Life could’ve inhabited the planet but the big question is whether it was actually inhabited. And so the next rover that we’re sending has a clean slate and will actually try to sample pieces of the planet for later retrieval with the intention of bringing them back to Earth. But the big question is where do we send the rover to search for life? Many brilliant scientists have gotten together and narrowed it down to eight candidate sites to go to. And just recently over the last couple of months they’ve narrowed it down to just three candidate sites. Now they have the difficult task of determining which one is the best site to send the rover to so that we have the highest chance of finding life. This gets at a really philosophical question of whether we should explore the places that we understand the most or just strike out into completely new areas that we’ve never been before that perhaps give us a higher chance of uncovering something fundamentally new. Even within that scope we also have to think about how wide we are casting our net. For example let’s say we landed a spaceship in the middle of Iowa. Iowa is relatively flat, but most of the rocks there have been deposited over a really flat terrain and their aren’t a lot of really old rocks to be found there.
Smith: So if we decided to land somewhere like that on Mars it really wouldn't be as conducive as landing in another location. But with so much space on Mars how do you pick the right place?
Adam: How do you pick the right place indeed! The scientists that are trying to figure out where to land the rover are weighing these decisions based on satellite images and previous geographical knowledge to try and determine the age ranges of rocks in certain locations, the type of rocks that reside there, and if they’ve been heavily impacted with craters. Actually, if the locations have been heavily impacted with craters that may prove to be useful.
Smith: Because the impacts bring rocks from the past up to the surface!
Adam: That’s exactly right! The impacts may have exhumed and scooped out all of the younger stuff on top and exposed the older stuff. It’s also possible that the impacts may have provided enough energy to create hydrothermal veins that harbor life. Instead of obliterating any life that existed in these areas these impacts may have provided the stimulus for life.
Smith: This decision on where to send the rover must be very complex. On the one hand landing the rover in a flat area would be safer for the rover to traverse, but the rocks there would be very young. On the other hand landing the rover in a mountainous region or in a crater site would be more dangerous for the rover, but would most likely contain older rocks that are more likely to contain evidence of life.
Adam: Exactly. Think about it in the context of Glacier Park. It’s a beautiful park and there are rocks there that span a wide range of ages. Some of those rocks are 1.5 billion years old while others were formed in the last month. It’s hard enough even with my bipedal human body to climb up a mountain and find these old rocks. It’s a little bit more difficult to do that with a billion dollar rover with wheels, a bunch of delicate instruments, and a tiny nuclear reactor. So you have to trade off what you’re capable of, what you’re looking for, and the range of times and environments that you’re sampling in. There is no single answer. That’s partly what makes it interesting and that’s partly what makes it’s so frustrating. At the end of the day we have to make a decision and we have to agree on it. This isn’t just a problem for scientists, but also the public who’s going to be following along. We all have to agree that when we go to a new planet we’re going to have to make the best of the situation we have.
Smith: I think one thing that we have going for us is that we have a very engaged public. Whether it be interest in physics, space exploration, or science in general the public is very interested and invested in our scientific endeavors. I think the public is also beginning to understand that our planet isn’t going to last forever at the current rate we’re going. And of course people are just as curious as we are about what’s out there in space and whether or not we’re alone. I’m very optimistic that these endeavors will happen. Maybe even in the near future.
Adam: Oh most definitely. Just even within the last week we’ve had SpaceX reusing it’s Falcon 9 First-Stage rocket! The prospect of reusing something more than once opens up completely new ways of exploring the solar system. Even if it’s a completely expendable mission all we have to do is just send more fuel. That opens up almost the entire solar system to a new reach that was previously much more difficult to attain. So if we’ve just crossed the threshold of the reusing the way to get out of our planet’s gravity well and we begin to figure out ways to hop around in gravity wells of other bodies throughout the solar system, the entire solar system itself opens up. I think the returns on what we could possibly find or build once we are operating in space far outstrip even the scientific prospects of figuring out some of these really fundamental questions that we’ve wrestled with for thousands of years.
Smith: The idea that we may one day be able to send a spacecraft to one planet to collect samples and then send it to another for the same purpose fascinates me. It allows us to sample so much more of the universe so that we can increase our sample size more than ever before. That’s really been one of the constraining factors of the past. We need more data. I’m sure a thousand years from now we are going to look back and laugh at how we were debating on where exactly to send a rover. In a thousands years we’ll be able to probe entire planets!
Adam: And perhaps the devices of the future will be fundamentally different than the ones we send now. NASA has a fantastic record of successfully getting missions to Mars and they’re unparalleled by any other space agency or business in the world. I think they’re going to serve as the foundation for all of these industrial and scientific endeavors for exploring the solar system.
Smith: Well I’m excited for that future. Thank you for taking the time to talk with us about your work on the origins of life and giving us your predictions about the future.
Adam: I’m very grateful for being the chance to speak with you and to have met a lot of the amazing researchers here at ASU who are working on very distinct and separate problems that help us to put together a better picture of the origins of complexity itself. It’s very fascinating.