welcome to the science for the public lecture series science for the public is an organization committed to bringing science information and issues to the general public this is our website no group at harvard university he's here to discuss the evolution of you carry out excels the foundation of all forms of complex life on earth another very exciting area of his research may challenge the assumption the emergence of life depended on the water medium his finding suggests that a unique water alternatives solvent may have supported the emergence of life and that's a big excitement dr adam received his ph d in earth sciences from montana state university in two thousand and fourteen and he represents the best of the trend by combining his expertise in paleontology astro biology and engineering he's also founder and director of a group called the blue marble space institute of science and he will be telling us about that as well tonight we're very pleased to welcome zach welcome dr adam thank you and could you start us by giving us a little bit of foundation about the origin of life why is that difficult and and then the maybe the three categories ok right well there are two basic approaches to reconstructing the really deep history of life and what i see the deep history of life i'm talking about you know before there were dinosaurs before there were fish before there were clams or mollusk or any of the kind of organisms that we would recognize today in today's oceans and on the land before that there was this great vastness of time for billions and billions of years on earth's history where some really fundamental transitions took place in an evolutionary sense in an environmental sense in just about every sense you can imagine the problem going back is that we have fewer and fewer rocks to tell us about this these time periods in these evolutionary transitions so in trying to reconstruct what happened on the basis of the available evidence we have fewer rocks to work with as we go backward and we have a kind of limited assortment of tools in a physical and chemical sense starting at the beginning and trying to work our way forward and so what we try to do is to take these  datasets and try to find where they meet in the middle working from the very deep history forward or moving from the current time backwards so we're talking about the emergence of cells and could you just refresh our memories on the three categories because i think you work on the complex one sure yeah and so that's one of the one of the most so i studied two of the most profound transitions that are or are thought to have occurred in the history of life the first being the and then much later on in about earth's you know midlife if you want to think of it that way all of a sudden we see these very complex cells showing up and these were much different then the other two categories of life bacteria are k and these are you car and these are organisms that can really dynamically reshape the external structure of their cells they have their genetic material kind of sequestered in a special part of the cell called the nucleus and there's there are a lot of are kind of complex regulatory mechanisms that allow them to change shape to have very complex cell cycles and it was the innovation of the earliest to carry out excels that eventually led to us and trees the algae and and slime molds and all kinds of other fascinating creatures that eventually came to inhabit the entire surface of the earth and so when i look back as part of my work to try to reconstruct the emergenc very advanced complex life we're trying to say ok what was it about arcadia and bacteria that helped or may have led to the evolution and emergence of you cario what was it about the environment that might have been emerged about when right so let's we can kind of run through the earth formed around four and a half million years ago it's not exactly clear when the origins of life occurred but it was thought to have occurred relatively early and in fact as far back as well as we have kind of really comprehensive packages of rocks we also see indications that life exists that that time so that goes back to about three three point five maybe even four billion years ago the emergence of you cario it's was followed by occurred about two or one point five billion years ago so there was this really long period of time two billion years like half of earth's history where bacteria and arcadia ruled the planet they they ruled the show they ran the show and so and once we see you cario it's emerged in the fossil record they seem to have emerged fully developed we have almost no transition states going from these really simple bacteria in arcadia to this you know monster of a you carry arctic fully developed cell and so part of the puzzle is what were the intermediate steps what they look like and it's it's it's made a challenge all the more made a challenge today because the more we look around we can sequence organisms from everywhere around the world in all kinds of environments and we really don't see much in the way of intermediate stages of complexity between bacteria and you cario i see so you have to do a lot of real struggling and inferring baby to try to reconstruct because a lot of that would be lost with the geological ages i guess right any case let me ask you now one of the most interesting things that you have come up with in your own work is  questioning whether they're water which we type to be fundamental to life and you raise the question you're not so sure about that could you explain why why do we assume water is essential for the origin of life and what what you came up with and then we take a look at your fossil fuel sure yes so this goes back to this goes back to the origins of life and water really is thought to be fundamental to all forms of tell water is the medium water is the the solvent that all of our metabolic engine etic reactions take place in our bodies or or in any form of life and in fact it it's to such an extent that we guide our search as for life in the universe on the basis of is there water there or not so in some of the work that i and my colleagues have been doing pathway to creating a solvent that is not water but that has many of the beneficial aspects of water in terms of a chemical sense but that overcome some of the problems with water so what you may not realize is that while water is important for all forms of life water is kind of a mixed bag when it comes to being alive in this bag of water right now so every moment of every day  your body is metabolising is taking an energy because the water is actually degrading every nearly every molecular component of your body at the same time it's providing a home for us all in our actions are going to replace there's a paradox there but at the same time you know our enzymes are breaking down our water spontaneously our d n a is spontaneously breaking down in water and if we don't have these kind of error correction mechanism that's going on all the time we quickly will degrade into nothing more than just a kind of pile of of gelatinous carbon and a bunch of water so this idea and this is based on chemistry that has been done and has been shown over the last ten or twenty years this idea is that there are compounds that are better than water for forming polymers and polymers are making up genes and they're making up basically enzymes and protein yes so it's been taken as a given that we needed water to originate life because water is in all forms of life that we know but if we can demonstrate that there are these alternative solvent and the one that we work with specifically is form of mind if we can demonstrate a way to produce for my on the very early earth when it was just formed in amounts that allow for a lot of chemistry to take place then theoretically we can start talking about  chemical systems that preceded life that were not as degraded by the conditions that water presents for complex molecules how interesting you just said it's been around the ideas been flirting around  here for about ten or twenty years that's been speculated i don't know if that's because they think it's possible on other planets to construct life where there isn't water but there is some solvent but well it was based on the idea because there are a lot of very talented organic chemist much more talented than i am who recognized that compounds like form of my this alternative solvent just if you if you removed the environment and you didn't you had never seen a life form before but you wanted to know how can i make how can i make a gene how can i make an enzyme for this grad these solvents have much better properties that as water and so they remarked on it from from the point of view of oh isn't that interesting that maybe there are other solvents that would do the job better if we were to try to engineer life from scratch the overwhelming problem was that there were no pathways to kind of geo chemically produce this solvent from the constituents that made up the atmosphere or the ocean and so what our team has has been working on and the case that we're making is that there are plausible scenarios where geo chemical reactions take place and rocks interact with the atmosphere and with the ocean to create pockets of earth where you don't have water at all you have for my other solvents where you can have much more interesting forms of polymer based chemistry taking place that are much more conducive to giving rise to life so the interesting question there becomes ok if that's what happened then where did water based life come from and so what we are conjecture at this point is that it's possible that polymer based chemistry could have taken place prior to the development of life they could have reached a level of complexity that was kind of very getting close to life but really wasn't self sufficient and that eventually there could have been some inherent bias or feedback or maybe even like a selective pressure whereby some forms of these chemically interacting systems could survive in water and others couldn't and that became the basis for life to originate and inhabit the entire surface of the earth with all of this available water having overcome the limitations of water degrading these  widespread use it something about pockets but it is it's you think of water is ubiquitous you know but right is is for our mind abundant in that way and that's that's part of the challenge is that no it's not it would have been and it would have been only found in kind of very specific types of environments at the surface of the earth so it is at the surface it's at the surface so this is a kind of geo chemically driven process where you put energy into the system these organic solvents are created they're collected in kind of sediment traps and pockets but we're not talking about giant lakes of rivers or for white or oceans of for my it's like puddles of them or maybe in the way that we think about oil reserves being held in pockets underneath the surface of the earth perhaps we had these rockets of really interesting very very complex polymer chemistry going on beneath or right at the surface of the earth that were in contact with bodies of water and then that enabled the transition to water based life as we know it i see if you go about getting your fossils is there any way to infer a good know that history from a fossil i would say it's very difficult because this is we're talking about a period of time millions you know say three point five four billion years ago when we don't even we barely have rocks that's just a tiny bits of minerals that survived from this period of time so what we look for are chemical indications from those tiny fragments of available rocks to say was the environment really hot or really cold was the service environment wet or dry right and then we look at the kind of chemical fingerprints of these minerals to say were there are a lot of terrestrial likes land rocks or were there basically just this really poorly developed kind of you know sheet of lava rams or metals can take many forms so we want to know how far along had the chemical evolution of the planet progressed and so that's really the within that very general framework of possibility we're left to infer what are the likely scenarios that would give rise to complex molecules right right but this is a very exciting alternative view certainly and i'm sure it's of particular interest to people doing astrobiology because there are  more interesting certainly we'll hear more about this i'm sure in the in the future now in the mean time you go looking for these extremely ancient fossils and i take it that a lot happened geologically and atmospherically and so forth over this long period in the earth as life is getting started so it might be hard to reconstruct but when you are looking for signs of earliest you carea it's do you do it with your little hammer and tap on the rocks right so when we go out to look for fossils of actual life life that we would recognize so not an intermediate stage between non life and laugh we have a pretty deep record at least we're pretty sure that we have a pretty verifiable demonstrably record of actual life it may have been simple it may have been you know bacteria in arcadia but we've got a record of that going back to about three and a half billion years ago  and then there was this long period as i said of about two billion years where not much seems to have happen or at least it's not recorded very well in the rocks that anything happened for about two billion years we see a massive transition in the atmosphere about two and a half billion years ago where we see indications both mineral logically and kind of in the in the in the record of certain elements in the rocks that oxygen shot up to unheard of levels i mean is unprecedented in the history of the earth and the earth basically had an oxidizing atmosphere from that point forward and it's never gone back and so then the another period of  quiet in the fossil record for another say five five hundred million years and all of a sudden we start to see fossils that look like they might be you cario and what's interesting about  far as we can tell they look to be kind of a kind mirror they look to be have genetic and metabolic pieces that are borrowed from both bacteria and r k assumed you can imagine them kind of is this man these are both massive groups of organisms very very complex and very diverse and yet the underlying machinery is this is if you were to take a deck of cards and shuffle them together you'd have you'd be mixing and matching different metabolic and genetic components to produce or you carry out a corgan ism that was capable of so much more than the mere sum of its parts and when we go out into the field yeah we're basically looking for indications when we're at the outcr that life has somehow manipulated or influenced the sedimentation of the rocks that we see is bostitch and so when you go out to the rocks where do you go what's  good place to go well i'm i'm biased because i did my work in west and central montana which has a very distinguished history in terms of its paleo biology so but he worked on these rocks and at the time they had very little concept of exactly how old the earth is they knew that there were all these rocks that had a very rich fossil record of animals and plants going back only so far in time and then before that they basically just said time x time y time z we don't know how old it is but we know it's much older than animals because there are no animal traces to be found and try as we might we don't see any recognizable organisms and what happened was that he was studying the rocks of montana and he noted about one hundred twenty years ago that there were these funny traces on the rocks and he didn't really know how to make sense of them he saw them he had been this was a time when you're really trying to figure out the basic structure of geology what how rock units relate to one another and he knew based on everything that he had seen in all of these rocks of all these different ages that the traces were almost certainly biological but he didn't really know what type of life it actually was so he basically did what we all do when we see something come confounding we we write up our description of it we take our best guess at interpret what it is and then we put it out to the community to see what they think and i've actually brought here and i don't know if we can say we go so i put a little helpful arrow at the bottom and basically it's this little round spot on this very flat piece of shale where it looks like there's a coiled ribbon that's been kind of compressed and preserved on the surface of the shale and what it looks like when when they first saw it and tried to make sense of it it looked like you know a child had come in scribbled with a crayon or a patent just drawing these little marks on this surface of the rock and they realized there was a very regular structure it has a constant with it has a more or less constant length and that it was more than just the random scribblings of of a child yes and what he thought at the time was that this was a trace fossil of much larger organism that it kind of scraped its way along the surface of the sediments which flew in the face of all established science at the time you know it was a very far out idea to say that over this incredible spans of time you'd have very complex organisms that are capable of walking across a sediment water interface to leave this kind of footprints if you will  in the trace of the mud without any trace of their body so this and a number of other controversies kind of stewed for a very long time in the field until the evidence became overwhelming that indeed there was life at the time it's just not of the body type that we would associate with animals and so there is this this evolutionary history that vindicates darwin's views that animals had been preceded preceded by organisms of you know gradually increasing complexity over a much deeper history of earth's history is that something i take it that the area that you investigate in montana it's not that kind of fossil record is not abundant across the earth i mean that's selected places so montana and where is it in montana the rain drain so there are a number of places and basically all along the border between montana and idaho you get these rocks called the belt supergroup that show up beneath rocks of you know that have things like bones and plant fossils and things like that and they basically show up everywhere from if any of our viewers have been to glacier national park and seen the magnificent cliffs and just these massive exposed layers and layers and layers of sediments that are nearly unbroken and you can you can walk right up it like steps for literally you know miles in height or kilometers and you're going back in time you're going back you're a billion and a half years known earth's history and those rocks really crop out throughout all of the area i'm going from up near the canadian border almost down to yellowstone national  really the almost the entire western edge of the state so for whatever is exposed that's very rich for this kind of a history because it's not preserved everywhere on earth right and so and so there are probably you know half a dozen really good localities that preserve the traces of these fossils from around the world i got interested in this project because when i looked at a map of where all of these localities were i saw that they were in very difficult to reach places there inside syria there in central china there in northern australia there in northern india but you know i as a as a graduate student i can't go to those places to look for life and i had known that there was this history of the paleo biology of the belt supergroup in montana because of fossils like those that had been described like great pen strong metal lights which of these kind of domes accretions of you know of sediments that are indicative of biological activity and so what i wanted to do was to say ok within this very large  body of rocks are there other traces of fossils that might provide more insight into the origins of you cario and there had been some work by a man named bob were diski he had wor on trying to dissolve away some of these rocks and when you dissolve away the rocks you're left just with the organic detritus the little the junk that's left over and if you dig through this detritus carefully enough with a microscope sometimes you find microphone and so unfortunately he had passed away unexpectedly and no one had really picked up his work and so i i designed a project to kind of pick up where he had left off to it's a it's a very it's a relatively easy process you are in the field and you're looking for the kind of rocks that really fall apart easily when you're in glacier national park you can climb these magnificent cliff faces because the rock is very it's a very hard rock it's very lithified and i was looking for the opposite of there and of rock i want muds that just fall apart in your hands and so the outcrops tend to be much less and and so you go to these sites you look for these types of rocks with these properties you dissolve away the host rock with hydrofluoric acid anyone who watches breaking bad knows about hydrofluoric as in that's very dangerous  and then you dissolve away the host truck and then you do through what's left and and you find these magnificent fossils that have like i said you carry oats are renowned for having this very dynamic ability to reshape their their cell shape to take on many different forms to form walls or doors in the opening of their cell wall and then to close them up again and that's exactly what we found when we looked very very closely amazing and so you brought some examples i think from your most recent trip that's them from this summer and can you show us that can you tell us about them a and this kind of gets in on this last trip we were trying to really get firm dates like exactly how old are these rocks and so while we were visiting the outcrops it's very rarely that you find any specific indicator of life without finding other indicators so actually if you go back for example to the site where any of the little scribblings on the rock are found if you look closely you'll find other indications that life was there and so for example if you look at this specimen this is actually called an elephant skin texture and it basically looks like elephant skin like if you ever  can see that there are some folds right down here on the board and it looks like there was like if there was a very thin tablecloth that was sitting on this surface and you were to push downward over then it would kind of bunch up in these little folds down at the bottom and you can see some others that are on this site as well so basically what this looks like when we're looking for indications of life in the field what this looks to me it looks like micro as had there had been a very fine surface of mud in the bottom of this body of water microbes inhabited that interface between the water and the mud bottom and kind of solidified it made it into a kind of glue and then maybe some current scheme change direction to push that around a little bit just like if you're pushing a tablecloth on a table or maybe the slo adjusted slightly and so some of it was slumping down and it created this kind of fold textures in the surface it's not a direct indication of life but it's it's a kind of in indirect or an associated signature a very very ivory it's a very low relief you have to be kind of looking forward again detail and these are also asymmetrical like ripple marks are going to be usually are going to be very symmetrical  particular microbe or it's just undefined this one is probably just undefined on its head more or less probably just a bacterial or r k o culture ok but if you were to go back what this would say to someone in the field is that ok if you have all of these other traces of life like great pannier like these kind of microbial e influence structures or surfaces you would stand a reasonable chance if you wanted to focus your efforts to find microfossils you would want to look in this particular locale rocker this cuellar rock type ok r i and so you came up with some other goodies and then we've got and then so part of the challenge of this  there were is that you don't always know what you're looking at and sometimes the question the jury can be out for a very long time as to whether you're dealing with an actual fossil or a dubio fossil or a pseudo fossil something that you're just not sure about so there's another type of fossil that is found up in glacier national park it's called it's named after bob or disk and it's basically looks like if you had taken kind of a string of beads and kind of gently pushed them into the mud surface and then lifted it up there these kind of round shapes separated by equal distances along a line and i i happened to be out in the field and the sun was at the right angle and the sediments had kind of eroded away in the right way and so i actually found another type of fossil that looks like it might actually be a specimen of or a disk but you can see all these you can see all of these little pits in the surface here and you can see that they're all more or less kind of equally sized and the problem is that there are so many of them here it's really difficult to resolve whether or not each of these tiny little pits are actually in a line or if it's just a bunch of equally sized compressions in the surface so this would be something that you know i would hesitate to call this an actual fossil i would rocks that are in glacier national park are roughly the same type of rock and almost exactly the same time period as this rock so by inference you have some basically saying ok i should be here looking at the  i see but it's you know three hundred miles distant from from this particular oil but all in all that area must be very rich in this very early period of fossils right you know what to look for is this shell oh yeah there's all this is it just looks like it would come off very easily can you just sort of slice off pieces and have a look i you know all the time i often i'll take a geology hammer in the field but oftentimes if it's the rock that i'm looking for i really don't need it i can either of these particular specimens i can just kind of pull them off the crop with my hands because i'm not looking for the really well with the  they show up because they're on these really stark cliff faces where you can see each line on the isn't that something yeah so yeah there's a depending on exactly how you're looking and what fossil type the history of the rock may preserve different types of fossil theresa's than others so microfossils are great in the soft shales fossil such as great penya which rely on you seeing them in relief with these kind of large plate like exposures the rock needs to be a little bit more cooked to show up like that at the crop and to be visible to someone who's was looking i see at and you're likely to find it just want to verify that the that this these kinds of fossils  might be in similar layers around and these selected places on the earth are a kind of an indicator of a particular time period perhaps or insecure on our theory and in a particular environment and perhaps a particular kind of history of preservation of the rock itself ok i would like to get one other thing sort of clear so when you're looking at the ancient you carry outs are they quite different from what you would see in a modern you carry out a cell so that's part of the challenge of our work we're particular rocks are about a billion and a half years old and a billion and a half years is a lot of time again to evolve from one thing into something else if you give me a billion and a half years i'm sure i'll evolve into any number of creatures but i can imagine just given the time and it's the same it's the case even more so for small organisms because they have a very fast turnover rate they have been very fast kind of lifespan if and so the generational time to manifest evolutionary change presumably is a lot faster part of the puzzle though is that when we look at fossils that are of this age they don't seem to change for hundreds and hundreds of millions of years so why didn't they change is it just apparent like is the morphology that the morphologies that are preserved are they just tend to be of one particular type or small subset of types or was evolution just fundamentally different somehow was the rate of evolution different because the environment was different or there was some missing genetic component that allowed them to change with greater frequency these are all open questions and so when we when we when we try to compare the fossils that we see to things that we see today we have to be a bit skeptical about equating morphological similarity to genetic similarity or species similarity i think but we might be able to extract very specific kinds of clues like if they grew for example by shooting and growing tubes out of the surface that's a very metabolically expensive way to grow so you must be getting a lot of nutrients back so you can say something about was it perhaps photosynthetic increasing its surface area or was it trying to absorb nutrients like a fungus would like when they when you see the fuzzy growth over fruit was it something that was more absor in its metabolic strategy so you can draw these kind of top level inferences but you're very limited by how much you can make that i see and that's i make sense that that might be a question for some time because reconstructing at that level is really quite difficult i would imagine there'd be things like astrobiology fields like astrobiology that really salivating about what your but you're doing here is that true and are you interested in that also maybe better tell us what that is right yeah so astrobiology is the search for life in the universe and we we're at a very special time like even when i when i was in middle school and high school there were at that time there were nine planets in our solar system something there were eight because pluto's of the our planet but thats it you know there are a lot of moons but that's those are the only plan is that we know about and now we're literally at the at the time where announcements of discoveries of planets around other stars they come in batches of ten hundred or a thousand depending on how they're serially it's seems like every week or every month there's a new exoplanet discovery of a planet outside of our solar system so nasa in all of its foresight anticipated the discovery of lots of planets outside our solar system and they wan know a and this gets back to our fundamental transitions that i study a what are the conditions that life is going to originate on any number of those other planets and if so what is it probability so what fraction of those planets have life on them and b what fraction of those planets that have life are likely to have complex and advanced life and then you can go up to higher levels and say ok what's the probability that they will be technologically complex or something like that but understanding the constraints or the drivers of the emergence of life or the emergenc fundamental to understanding whether it's half of those planets with life or ten percent or one in a million one in a billion and so closer to home we look for these traces of you carry o life because or any life really in the in the in the deep fossil record because we want to know if we're for example sending very sophisticated rovers to the surface of mars and we see all of these beautifully preserved sedimentary structures the scientists and engineers in control of that rover want to know do i go to that outcrop or do i go to that out rob and when i go there which part of the crop do i focus the camera this outcrop versus the other and it really gets back to the nature of how these particular fossils and others like them how do they show up at the crop and what's the probability that if they're right in front of us that we're going to be able to recognize it given the resolution of the can ever actually so even here wrecked late it's a very direct link and even here when i'm i'm holding up specimens for the camera to try to resolve what the features are and we have fantastic lighting and we have state of the art era technology and we have very talented camera crew working everything to get it just right when you're beaming these images from you know millions of miles away it gets really challenging really quickly i want to make sure you're looking for the right traces of life yes that is really neat and what an exciting time to be lying there before we and we're about out of time i'd like to ask you about the organizations that you were a part of if you could just give us an idea of what they do sure yeah so my the origins of life research i'm not doing this alone i have i'm working with some really talented people both here at harvard in the origins initiative origins of life initiative and in japan at the earth life science institute and so on the research side of things  i've worked with a number of people in terms of outreach because as we have seen with the cutting of a lot of budgets in scientific institutions the funds available to do outreach in to explain just really at a basic level what is it that i'm doing what i'm spending weeks out in the woods if i'm going around looking for rocks and explaining to the public like why is that important and what's the kind of benefit they're going to get  those funds have been reduced so substantially and a group of my colleagues and i started an organization called blue marble space and we basically put our extra time into  communicating to the public exactly what we do how it benefits them and what some of the either downrange you know cultural impacts of this work is going to be i mean asking about where life came from and whether there's life in the universe is possibly one of the oldest scientific questions we have and so it's not a trivial thing that i invest time into studying so our lives are really just to explain to people and to take the time to try to increase our ability to explain to people what we're doing and why it's important well you just did a super job thank you so much and it is good to remind the public to the terrible cutbacks in a lot of basic research research in general and i hope we will see a change in that but i certainly agree with you that this is having a seismic effect on our global culture as people become aware of this and relate what you're doing to outside the planet which is a very recent thing i mean the space aliens have come and god many times we don't hear about it anymore you know what but now there are these more really serious questions we're limited by the types of molecules that are found in life to try to see how they change their environment if we could reconstruct new forms of life we could possibly be engineering them to to solve very basic problems we could be engineering a form of life that draws c o two out of the year and does not do any other metabolic activity to help mitigate climate change for example that's not something that you think about commonly when you think about we're not but there are definite technical possibilities that will better our lives to fall out of fundamental research that's really an interesting point thanks for bringing that up because that's not we don't usually think like that but with all the biological engineering going on that's