like i had experienced and was carrying from a young age trying to answer a lot of questions and fill the void in my own education i hadn't had the answers to end the book was a process of attempting to fill those gaps. >> to watch the rest of the program, visit booktv.org. search for clint smith using the search box at the top of the page. >> jeremy is an anthropologist and : editor, the most interestg problem, what garments descent of man, right and wrong about human evolution. he's part of the research team that discovered two ancient members of the human family tree. he studied wild chimpanzees an early human fossils and museums throughout eastern and south africa from 1998 to 2003,

working as an educator. senior editor at scientific american, she's been writing about the evolution of humans and other organisms for the magazine 1997, also co-authored donaldld johansson the legacy, e quest for human origin. tonight will be discussing his new book, how upright walking made us human. in it, exploring the history of the ability unique to humans among living mammals to walk on two legs. he makes the case that this would be a crucial change that allowed for the evolution of humans despite difficulties for thereafter. praising his love of the discovery and collaborating with colleagues comes through in the one of the expenses examining this firsthand. his ability to turn evidence into axp focused tale of human

evolution and enthusiasm for research will leave readers informed and uplifted. i am pleased to turn over to our speakers, the digital podium is .ours >> thank you, i appreciate the introduction. >> good to see you, thank you so much, i'm delighted to have the opportunity about this fabulous book about all the things i get excited to write about such a pleasure to be here and i thought if you're up for it, we can kick off the conversation by having you tell us why, humans have things different than other primates, we have naked bodies, large brains and language so why

focus on best? >> it's a great question. like you said, we have these differences, we have lots of similarities, primate cousins but we have differences as well. upright walking is one of those. mammals fly and swim and sprint and leap, mammals walk and climb. your typical mammal moves around on all fours, think about a cow or sheep, a dog or cat, they move around on all fours but only humans will navigate the world on their extended hind limbs all the time, it's a strange way to move. when another mammal does it, we kind of lose our minds. we take out our cameras and take a video and post it on youtube and get millions of hits. i was researching, i found

examples of bears moving on two legs in new jersey, a bear named petals and there have been almost 5 million viewsws about bear walking on twohi legs walkg through the suburb. a guerrilla in philadelphia zoo, lewis started walking on two legs occasionally, so they got a ended up on the cbs news. something we do all the time, to describe something ordinary when another animal doesn't, it's remarkable but not only that, the fossil record, which is, i am a a paleontologist, i study fossils, what we can tell by going back in time to common ancestors we shared with cousins, the further back we go, we start to lose this unique characteristic, large brain, evidence for language, this has happened more recently.

the most ancient characteristic we think on our lineagek is this ability to movede on two legs so not only is it really strange but it's the most ancient thing, they set our m lineage off and i argue in the book that it was the key innovations that led to many of those other anatomical behavior strangers that make us human. >> that's an interesting lens to view the entirety of evolution in a sense. this might sound like a weird question but from your beer, we take upright walking for granted and we don't think about it. what is special about it? can you describe the act of

walking on two legs and what's unique about it? how do you convey that? >> it's a balancing act moving on two legs. i stuck talk to my students about imagine if i give you an assignment to design me a chair, he would probably design it with four legs. there might be other students who make a barstool and make it into three legs but if you make it with two legs, it's probably not going to work. the student would fail the assignment. to lake is an unusual way for a memo to move around the world today but we can get into locomotion at some time and deep in the past we find evidence of dinosaurs and even ancient crocodile ramp which is fun to look at but this is about

balance. what we can see and one way to identify fossils coming from things adapted to move on two legs because they have specific shapes to them, individual bones that would align the joints in a way to prevent us from tipping over or change the action of certain muscles so the muscles would act in a way to prevent you from tipping over. ... sure enough she's got this

hip joint arranged in a very humanlike way so even if this is the only part, we would be able to tell that she was able to balance on a single leg and why else wouldd do that unless you are moving around on two legs. but from a biomechanical standpoint, and really connecting it to natural selection. and in addition to that, we are stunningly slow for a mammal.

the fastest seat was 28 miles an hour in his hundred meter -- in 2009, his world record. 28 miles an hour. it's half the speed of a galloping zebra. half the speed of a galloping antelope and half the speed of a lion and levered. evolving this form of locomotion made us slow and raises some interesting questions of in what ways was this beneficial and allowed us to overcome some of those i suppose you could even frame and as. >> you anticipated my next

question which is why evolve this. i know there's been a lot of scholarship over many decades and all kinds of ideas and they come to have this unusual motios and there's some interesting ideas going back as far as darwin and i thought it would be fun to take a tour if you wouldn't mind indulging. what does this other man will do or eat, what are its patterns or what ecology does it live in in which this form of locomotion is beneficial, and so as a

scientist when you f are tryingo figure out something about yourself, you want to look out into the natural world and say where else do we see examples like this and the fact that we don't have other mammals that habitually walk around on two legs have some difficult scientific problems to solve and it's one d of the reasons that e haven't solved it in that you can go back to pick it right up until 2021. people are still hypothesizing why it was selectively advantageous for our ancestors. that goes back to interested in being able to stand and see off into the distance. with that one, if you look off into the distance and see a predator, the worst way to get away from it you would want to be down on all fours.

that one has never made any sense to me. there are ideas about darwin's all thisde connection between or small canine and tools but this is about framing the hands for tools and that becomes somewhat problematic although i think it is an interesting idea worth revisiting. but problematic because of the timing. but we have evidence for in homonyms that are six and maybe even 7000000-years-old. and wen don't have evidence for the tools until about three, three and a half, 3.3 million years is the oldest reported evidence. and then there were wild ideas about displaying genitalia, that this is somehow showing off your body for selection. the ideas that are a little more reasonable having to do with food sharing and if you can free

the hands not to make weapons or to risk but to gather food there's ideas were the females are gathering food and sharing with others. and then argued is that the males collecting the food and sharing it with potential mates. an idea that has a little bit more may be lasting power has been about energetics and moving on two legs. we are slow but we are energeticallyes very efficient d one of the best ways to explain this, and i talk about these ideas and he said that in order to lose a pound of weight, you have to walk about 70 miles because we are too good at it. we are two energetically efficient so you don't want to

lose those individuals moving in a way that is energetically efficient might survively better so that is a possible idea as well. there are lots of hypotheses and that's okay. there are i going to be plenty f things new discoveries will allow us to go back and revisit these ideas and really the issue for me is not figuring out which one is right but beginning to eliminate thet ones that are clearly wrong. that's how science works by refuting the ideas.

we can talk about some of the fossil discoveries that have allowed you and your colleagues to start to piece together a lot of folks listening will probably know about lucy there were footprints found at the site in tanzania and those are those ary

important discoveries showing that existed three and a half million and yet the genetics would point towards a common ancestor that we shared at about six or 7 million between the two is complete by 6 million years and what's going on in that timeframe. they haven't been made but they begin to piece the story together. 1 is a partial skeleton like lucy or are the pacific us has some of the key morphologies of the pelvis and the foot that would indicate at least it was occasionally able to move around

on two legs when it was on the ground but it also has a big grasping toe on the foot. that is 4.5 million something then if you go further back than that, the evidence becomes much more controversial and a little more difficult to interpret so this is from a five and a half-year-old homonyms from ethiopia and it matches the shape, especially the end of the bone of the human toe that would push off the ground when you are walking whereas a chimpanzee it curves in then other direction and this has a curvature to it that it's more likera an ape so

definitely it has an angulation like yours and mine meaning it probably would have been able to push off the ground so this is a cool fossil but it's just a toe. here's one from kenya that's 6000000-years-old and what's unique about this one is compared the head or the ball part of the hip joint, very similar but lookad how short the neck is and how long it is on this fossil. it's about repositioning those to get down on a single leg. by drawing on the muscles farther from the hip, it makes it more efficient and we can think of that anatomy as evidence for the locomotion and

if we go back even further than that, there's a remarkable school that was discovered and is very controversial. the researchers that founded and first interpreted it argued the whole atat the base and maybe en walk on two legs. we don't walk with our heads, so i would like to see fossils from other parts of the body and there is a femur now that has been copublished by one team and another has a print and they come to completely different conclusions on whether it is uprightt or not and to me as you converge you're going to get something that isn't quite like

any of the living apes and a fabulous combination and maybe a frustrating combination is difficult to interpret. it's kind of what you might expect in a common ancestor. >> do you think that this looks like it or no? >> i like to talk about fossils i've been able to see and this isn't one that i've been able to see myself. however there are even older fossils now we don't have much from 8 million, 9 million, 10 million but there's this new discovery from a site in germany and germany might sound sort of surprising to some of the folks

listening but in the late scene, apes expanded all around the mediterranean and we are living in italy, greece, germany, turkey and hungary. this new fossil from 11 and a half looks like it's very upright and to me that is an interesting find because it could imply and we are still trying to figure this out but if the body formed by which it evolved.ol there are a lot of t-shirts and coffee cups and bumper stickers that would expect a chimp turned into a human and chimpanzees are not our ancestors, they are our cousins as the common ancestor

is one thatn we branch from but so did chimps so it isn't a given that that common ancestor and some of them that we are finding might indicate the common ancestor was more upright in the trees and that could be a more derived form of locomotion. there's plenty of researchers and colleagues that would disagree and think it is the form from which it evolved and they've madeup compelling cases fore that. we need more fossils to figure this out in the room. a. >> it isy a really revolutionary idea and it's fun to think about that. now if this is a uniquely common trait and its 10000000-years-old, is it

potentially a homonym? >> i don't think so. i don't think the timing is right and i think the genetic data shows very clearly when these were branching. having said that,e there are bas around these divergent states. i think you raise an important point that our field has always operated under the assumption that if you find anything that shows characteristics of upright locomotion it is automatically by definition a homonym meaning it is an extinct relative of us and it would be more closer to us than any of the apes. and i think that assumption is on the table as maybe not being 100% correct because if you had

apes experimenting with different forms including upright in the trees they might have some anatomies that look more humanlike for instance in some ways it looks like lucy and i think that is telling us about the like positioning not necessarily weight-bearing on a terrestrial leg but an animal in the trees moving with hand assistance like orangutans sometimes i do. spider monkeys will do this but it would mean fighting evidence may not be enoughsm anymore to claim the homonym status. this is going to be fun as we find more fossils from that

five, six, seven, eight, nine or 10 million period we will see lots of experiments going on with locomotion and lots of false starts and places where it may have been and then that animal died out. it just was not a selectively advantageous form of locomotion as a habitat the habitats changed. >> we talk a little bit about the origin and you mentioned this very briefly that there are other kinds of we can look at to sort of study the emergence.

you mentioned a place i always wanted to visit that seems like one of the most iconic sites even just thinking about it kind of gives me chills. so, there is a very famous set you are seeing the behavior. what does that tell us about the evolution at that point in time which is 3.6 million compared to going back? >> it's good footprints. that place is magical. it's amazing and there are

footprints eroding out of the hillsides and like you said, i love fossils and we can squeeze information out of them and tell stories about what our ancestors like from these bones but footprints are alive and telling you about this moment in time in the life of a living and breathing, thinking individual who was a lot like us and a lot of the recent biomechanical work that has been done is telling a story of something moving a lot like us. it isn't hunched over, crouched down like a groucho marx walk or chimpanzee moving. it's something from a distance

would look like you and i walking. if you could put it on a treadmill, you would pick up some subtle differences and that is a fun thing to think about. from the footprints and the bones it looks like they are not pushing off quite as much as we do. the arches are a little flatter, their legs are a little shorter and theyyb may not be extendingt the hip quite as much as we do when we walk that the differences h h are subtle. 1 of i think the amazing discoveries of the last ten years is that we often think of it in a linear way. i'm interested in talking but what we see instead are different forms evolving so at

the same time there was another that was in ethiopia not far from where lucy was found climbing trees and walking by a mechanically in a different way. it's a fabulous discovery in ethiopia in 2009 and it showed that there were these different forms and then behind me this skeleton here was discovered by the first thesis by his 9-year-old son in a cave in south africa also in 2009 is when they were published. i worked on the foot and the leg of the skeleton and when i first started working on it, to me i just finished my phd with the

homicides and homonyms and to me there was variation but not functional until this. what's neat is that this carries right up until and even on the doorstep of homo sapiens, you have neanderthals in europe, the indonesia islands and then right on south africa is a brand-new species a in 2015 so there were all these different species and

populations coexisting. some of them we interbred with and do some of them i don't think we probably did. but for the foot bones and leg bones it looks to me like many of them walked in these biomechanical a slightly different ways. so i love to think about jumping in a time machine and going back to these time period and see these different kinds of us, different species of ancestors. they would look a little different and begin with different things but they would be walking in different ways. not just something that happened in the scene when it was first appearing, but bright up until virtually yesterday in the

geological terms. >> and it's amazing. when i was in grad school the story very much was right up to homo sapiens and then what do we do with neanderthals and that's whatat we argued about. with a different species were they part of our heritage and now studying upright walking it wasn't really interesting. we had already evolved so let's go back to the scene. it's interesting. there's a lot going on there. >> if we go back to the earliest evidence we have like we do, it's interesting that the oldest are just a few hundred thousand years younger than those

footprints, so we are getting a little bit closer to what darwin was talking about potentially. and i'm just wondering how you see things aligning. could it be that it is what frees to the hands to start doing stuff like making stone tools. a. >> i think that possibility again is back on the table. he also incorporated brain size and enlargement which we know isn't part of the story.

the oldest stone tools at 1.8. 3.6, 2.6. we are getting closer. it did geto. pushed back. it's about 4.2 million-years-old and very humanlike. i would like to see what the rest of it looks like. honestly, i was going to say my hopes, but my expectation given how remarkable my colleagues are at finding these fossils. i like being out there looking for them, but you know, they are much better at finding them in the last decade or so, the last two decades and so knowing more

about that creature think is going to be important but back to your point, we now have at least reports of the stone tools of 3.3 million and they are controversial. at the same time, to me behaviorally i don't see any reason why they wouldn't be making these stone tools. there is about a 20% increase in the brain size and there is that new discovery on the basis of the juvenile skeleton that shows they slowed down brain growth and that is tied in mammals to learning and relying heavily on learning and this is a horrible idea. but also something that is going to be heavily created upon in the environment.

you would want to speed up rather than a slow it down and there are plenty of carnivores on the landscape. the fact that selection was favoring the growth to me tells a story of having reliance on learning and learning a lot. that might have involved learning how to make stone tools. but it also is a story of cultural buffering and cultural buffering. how do you survive on a landscape like that, how do you avoid being just picked off all the time is that you look out for each other and have each other's backs. so i think that our sociology is built into the locomotion simply it isn't going to be an evolutionary success unless it happens into something that is

either superfast like an ostrich or is super social and even compassionate and empathetic like we are. >> i thought that was a really fascinating point that you made in the book. >> linking to violent behavior and to now you make the argument that it could never work if our ancestors didn't have the capacity for empathy and cooperation. >> i think so. i think that idea of uprightness not just for tools but for weapons is part of the popular culture. we've all seen 2001 space odyssey. the beginning with the yielding

of the weapons and that has itss intellectual roots back to raymond dart who discovered the first who is just over my shoulder here, this wonderful little fossil. but later in his career in the 1940s post-world war ii, he worked at a site where he discovered bones that had been smashed and he formulated a hypothesis that they had been doing this. that they werehe these bloodthirsty killer apes. and that idea has had roots and again is still a part of the popular culture. even though we know now they were smashed up because of hyenas.sm it wasn't us. so the science has refuted that idea but it's still part of how we thinks about ourselves and instead, i draw attention to a fossil like this discovered in

the 1970s by the team in kenya and it is an upper leg bone of the early homonyms a little short of 2 million years with the long neck that's how we can tell it's from an upright walker but the cool thing about this fossil is that itup has a heel fracture. so this here, this bold shove bone sticking out of the inside of the femur that is a healed fracture. think about breaking your femur to million years ago no hospitals,s, no doctors, no fir, no shelter. you break your leg but you heal, you survive. that can't happen unless other individuals l are helping you o. and it's not just 2 million. back to lucy, there is a second skeleton about three and a half

million-years-old we think it is a large male and he has a healed ankle fracture so he stepped in a hole or stepped out of the tree and he broke his ankle. if you are a zebra and you break your ankle, that isn't a good situation. but you are still able to get from point a to point b. if you break your ankle you are already slow and now you are hopping around your landscape i don't see how you survive and this is a healed fracture so that individual did survive. in the vulnerabilities that we have, the fact that we have injuries that make us particularly feeble is again i think explainable only if we

were and continue to be empathetic and compassionate and generous and prosocial with one another. a. >> nafascinating. i know there are some questions from the audience that she wants to put to use so we will turn it over to her. >> i hadn't heard that. it's amazing. i had no idea that it went that far back. it was a discovery in 2010. okay it's 11 years ago now but still it's indication of how rapidly my colleagues are finding these fossils and putting them out there. each of these fossils has an amazing story to tell about why we are the way we are today.

so, it is easy for one to get overlooked. and that one definitely didn't get the attention that it deserved. it's nice to know that we can be nicer than we think and that is just very reassuring. we have a question here. if you were able to change human anatomy to make it easier on us, what would you adjust it is sort

of like evolution's example of a good try. you did your best. what happened here is you converted into something that needs to be rigid and to have moments of flexibility but also push off the ground in a way. soro we have the same 26 bones n our food that chimpanzees do so imagine you try to create something from scratch and it needs to be able to contact the ground, absorb energy and kick off the ground to the next step andic you make it out of 26 par. it just wouldn't happen. what's happened over the course of the evolution is the bones

that make up their ankle and foot have fused together into a single structure f that is composed instead of 26 bones it is about eight or so and this ends up looking aig lot like the blade prosthetic that a lot of para- olympians will use with great affect and can run very fast. i would totally change the foot. now the back is a bit of a mess as well. but the foot is the first place i would go. we will stick with the foot. >> branching off of that, we another question. do you think -- is it possible

in humans or anywhere else to evolve and improve anymore, like do we represent what it's going to be is that even possible to speculate on? >> it is the kind of thing i love to talk to my students about. if you look at all of these different body forms that existed, i don't see the human body today, homo sapiens as having some advantage of some of thee others. it looks like the joints were smaller so maybe the home range wasn't as large. oibut i certainly don't think tt bwe have reached a pinnacle of the locomotion. and again, i would much rather have the skeleton of an ostrich if i wanted to get from point a to point b on two legs.

for instance, there's a crocodile discovered in north carolina by lindsay who is a scientist at the state and, the museum, sorry the museum of north carolina. she reconstructed the date as being up on two legs at least occasionally so imagine this crocodile that would jump up and could spend. very horrifying and yet, what i find fascinating is that didn't have evolutionary legs. what happened to crocodiles, they are on all four and they

are ambush hunters. this wasn't evolutionary successful ultimately. you see that in dinosaurs also. the earliest dinosaurs. then okay, about s. aureus, brontosaurus, stegosaurus, triceratops, those evolved from bipeds. sso, bipedalism seems to pop up occasionally and honestly fail and either convert or be a did dead end lineage. >> you brought this up in the conversations in the reminders. what is the time span generally?

>> it's interesting it depends entirely with the body form of that common ancestor looked like. you would have to have intense natural selection to go from a common ancestor to something that isn't just getting picked off by leopards because it is hunched over and can't move either quickly or efficiently so in that circumstance i foresee this happening incredibly fast. or it happens incredibly slowly. if the common ancestor is something that is imagined more like a large given moving on two legs and then there is an environmental change and you

begin to get patchy it has to move across the landscape but it already has a body form to do that. in that case it would be very gradual, and what we would be looking for i think our enemies that are not from the biped but something that is a terrestrial biped. and we haven't even thought about what that would be as a field. how would you distinguish between something walking on two legs on the ground or different forces versus something moving on two legs in the trees were the trees are more compliant so the forces would be different. you probably wouldn't have to have because you are holding your body with your hands and so you're not going to have that pelvic tilt problem. that's something we as a field haven't really grappled with.

a. >> would it be hard i think just in contemplating the different scenarios that it would be easy to fall into this trap, sort of the way that may be by the time you are in your possession it seems it would be a pretty easy trap to fall into. >> i think this probably happened gradually and there is probably not one explanation for why it was selectively advantageous but it was a host of things. however, you know, so yes you've got an operation and its variation and certain individuals that move more than others, and they end up having more food and reproductive

opportunities and off you go ang we just try to figure out what it is that allows those individuals to have more food in those opportunities. there are other scholars that think that this was more. richard dawkins has written about this. he thinks that it emerged as sort of a meme, that it was just a cool thing to do and that chimpanzees and gorillas occasionally move on two legs and if that became for some reason the fad of the population, you could have more and more individuals at each other, which is what we do. and because it is plastic to an extent you might get some of the anatomies that are key not because you inherited them genetically but because you acquired them through your life.

so the best example of this, when you are born, your femur is perfectly straight. but as you start toddling around, your femur begins to angle in. but we are not born that way. when you find the femur as was done in 1973 and it has an angle to it, it tells us that this individual handy to have walked on two legs because there is no other way to get that angle. so there is a cool combination of an anatomies that you are born with and that you acquire that blend together in your muscular skeletal system. >> okay. thank you. >> we have matthew asking what circumstances are making it easy to find more fossils today? >> great question. so, like any science, you build

on the work of previous generations and there are lots of false startss that happened and mistakes made. you learn from the mistakes of predecessors but having said that, there is also a lot of technological advancess happening. 1 of the reasons my colleague has been able to find as many as he has is by having satellite imagery and looking at the clusters that grow out of caves. you can see them much better so that's one of the things that's happening. instead of doing parachuting science and dropping into these places and spending a couple of

weeks and then going back to the united states and western europe, a lot of us work now an incredible fossil discovery is being done by individuals that are from those countries. and many other folks. i'm curious what you would think about that. why do you think we are getting this? >> i also wonder if there is a little bit of the cradle of human time which is already pretty well explored and found these amazing things. so maybe we need to start going back to places that we thought didn't have any more fossils for

that we haven't looked at yet and you know, kind of a go in wh fresh outlooks. >> i agree i think that's true. that assumption many of the great discoveries have already been made. this last ten years i've just been astounded. that's happening to some degree but we are also finding things i don't think any of usus could he predicted. i certainly wouldn't have predicted any of them, so it's been a really wonderful awakening in our field and thus the humility for us to discover

and a lot of our ideas well end will endup being wrong and thaty as long as we are following the evidence, then it's okay to have an idea based on the evidence you have and then look at this new fossil. it shows i was wrong. oh well. t brand-new fossil. >> i think we can leave it there. we are about out of time. thanks to both of you so much for the fantastic and thank you for joining us. please learn more about this incredible book. i posted the link in the chat and others also want to donate. thank you for tuning in and stay safe. have a lovely night. thanks again to both of you.

the world changed in an instant, but media com was ready. we never slowed down. schools and businesses when thet virtual and we powered a new reality. we are built to keep you ahead. a. >> along with of these companies we support c-span2 as a public service. in their latest book i alone can fix it, reporters carol and philip rucker look at the final year of the trump administration. >> i think the honest answer about what we learned about donald trump is that all of the

basic boundaries of who he is and how he leads and governs are pretty well known by us. he's impulsive, interested in his own benefit. he's not so interested in anybody else's and also doesn't follow any rulebooks and rejects norms and cares very little about what washington should do, what's polite and what's proper. the new thing we learned that was even chilling to us as hardened journalists as we are is how much he was willing, the degree to which he was willing to put american lives and the democracy imperial for his own personal gain, for his own quest to maintain that grip on power that he became addicted to and loves. insiders in that administration

who looked from the outside and even to the reporters as if they were sort of silently acquiescing standing by their man were actually secretly in panic about the danger he was putting the country in during the black lives matter protests, during the pandemic that marched across the country and then finally in the riot to that he helped insight at the capital that put lawmakers and his vice president in the crosshairs an actual mortal danger. to watch the rest of this program visit booktv.org, search for carol or philip rucker using the box at the top of the page. in the