where they are already taking first steps so i say you know what, time to stop being quiet and stand up and get my opinions out there and hopefully change my mind so that is my goal here. i want to meet other people and say i'm speaking up, i'm not scared, i'm not going to be shut down. regardless, you have to stand up for what you believe in, otherwise you might as well laid out and thought. >> visit booktv.org, find the search box near the top of the page to look for patent dave brown or the title of their book, black and white.

>> were watching book tv with top nonfiction books and authors every weekend. book tv television for serious readers. >> and anthropologist editor, the editor of most interesting problem, what darwin's descent of man from right and wrong about human evolution. he's part of the research team that discovered and described injured members of the human family tree. he studied wild chimpanzees in western uganda and museums throughout europe and south africa from 1998 to 2003, working as an educator insight. heat is senior editor at scientific american, she's been writing about the evolution of humans and other organisms for the magazines 1907 and co-author

with donald the legacy from the quest for human origin. tonight will be discussing the newto book, first steps upright working for us human. in it, we'd explore the history of ability unique to humans among living mammals to walk on two legs and makes the case that it would be a crucial change to allow for the evolution humans despite difficulties exposed to this forever after. a lot of the discovery and collaborating with colleagues comeee through in examining it firsthand. his ability to turn evidence into a focused tale of human evolution and enthusiasm research will leave readers both informed and uplifted. i'm pleased to turn over to our speakers, the digital podium is worse. >> thank you, appreciate the

introduction. thank you for being here and doing this. >> thank you, i'm delighted to have the opportunity cap questions about this fabulous new book, about all the things i am most excited to write about so it is a pleasure to be here in about if you are up for it, we can kick off the conversation by having you tell us why humans have a number of traits from other primates, we have naked bodies, large brains and language so why focus on this? >> it's a great question. like you said we have differences we have lots of similarities or primate cousins but we have differences as well.

mammals sprint andnd [bleep], wk and climb, your memo will surround all fours, animals move around on all fours but only humans will navigate on limbs all the time, a strange way to move and when another memo as it, we kind of lose our minds. we take our cameras and videotape what's happening, we post it to youtube and it gets millions of hits in researching this book, i found examples bears moving on to legs, 5 million views of a bear walking on two legs in this suburb. the kareliangh barilla started walking onto legs, occasionally, not frequently but occasionally,

somebody got of it and it ended up on the cbs news something we do all the time and we even use the word pedestrian to describe something ordinary when another animal does it, it's remarkable but not only that, fossil records, which is what i work on i study fossils. jeremy: the linage of the wdisaa really strange, but it is the most ancient thing that we have all sort of said and what i

argue in the book is that it was the key a novation led to many of those other anatomical behavioral changes that make us human. >> that is great is really interesting to view the entirety of evolution in a sense read this quite semi- weird question but thinking about this from a biomechanics standpoint, we do it all of the time blocking a bright and we do it all the time we take it for granted and we don't really think about it. so what is special about it from theha standpoint of biomechanics and can you describe the act of walking on two legs and what is unique about it. any sort of convey that read. jeremy: it is a balancing act to move on two legs, think about when it's talked to my students about, imagine if i give you an

assignment to design me a chair and you probably could design with four legs. there might be some clever students to make a barstool out of three legs but if you make a chair onto legs, it is probably not going to work because a boy to sit and i'm going to fall over. and the student will fail the assignment, to leg and locomotion is pretty unusual way in for mammal to move around the world today. we can get into bird locomotion at some point and then in the past we find evidence of people with the dinosaurs and even ancient crocodile lineage which is really fun to think about. from the bio mechanical standpoint, this is about balance read and what we can see and one way that we can identify the fossils is coming from things that are adapted to move on two legs is because they have the specific shapes to them, these individual phones that wod

align the joints in a way that would prevent us from taking over or we change the action of certain muscles so those muscles would act in a way to prevent you from tipping over. while classic examples his hip joint w take a step, you a few of the leg, if all over. and when a chimpanzee walks on two legs, that is exactly what they do, they wobble from side to side but in humans we have evolved the pelvis when the muscle attachments here have dropped onto the side of the body and be on the side the and will counteract and tilt every time you take a step. so he finds part of the body, that looks like this you can tell something so you know very well, here's lucy's pelvis and sure enough she has those hip joint arranged in a very human

like play rated so even if this was only part we found, we would be able to tell that she was able to balance on a single leg and you do that if you're moving around on two legs. from a bio mechanical standpoint and really connecting it to deflection, it is not a great way to move around your world. we are incredibly and stable two legs, we fall a lot that can be quite dangerous, 30000 americans every year fall. and in addition to that, we are stunningly slow for a mammal, the fastest human was far as we know in several of the fastest he ever ran was 28 miles per hour is 100-meter -- in 2009 from his world record , 28 miles per our. and it's impressive, i could not come close to that but is half

the speed of a galloping zebra. and half of the speed of a galloping yellow and half of the speed of a lion also have a leopard read so evolving this form off locomotion made a slow. and so it raises some really interesting questions of in what ways was this beneficial and allowed us to overcome some of those adaptations mall adaptations. kate: you anticipated my next question which was why, what was a subpar way of getting around and so, i know there's been a lot of scholarship over many decades is with people coming up with all kinds of ideas about

why we did come to have this unusual kind of locomotion read some really interesting ideas going back as far as darwin and i thought it would be fun tode just kind of ticket mental tour through some of those ideas. jeremy: is one of those things where if there was another mammal the moved on to legs regularly. be able to test this more effectively, and we would say okay, what is this another mammal do. but is it eat what are its meaning patterns are but: he doesn't living in which this form of locomotion is beneficial and beneficial to the site is near try to figure out the microsoft noise want to look out into the natural say where else do we see examples like this and the factmp that we don't have other mammals that eventually walk around two legs, makes is a really really difficult

scientific problem to solve is one of the reasons that we have not solved it and you can go back toe the work and take it right up until 2021, still hypothesizing why this was selectively advantageous for our ancestors pretty ofm ideas about and going back to mark and he was very interested in humans being able to stand and see off into the distance.ta and with that one, if you look off into the distance and you see a predator, the worst way to get away from it would be, being down on all fours and yelp away because you would be much faster. so that's never made any sense to me. and there are ideas about darwin and he saw this connection between ourw small canine and bipedal realism and tools. but this was about praying the hands for tools and the becomes

somewhat problematic although i think it's an interesting idea. but problematic because of the timing and we have evidence for client. and, maybe even 7 million years old. we don't have evidence for stone tools until about three-point $3m years is the oldest reported evidence for stone tools. and then there while ideas about genitalia display and some sort of showing off your body for selection. in the ideas that are little more reasonable and testable having to do with food sharing of you for the hands of the make weapons or tools but to gather food. there's some ideas that have been promoted the with females are giving food and sharing it with others. nancy tanner's idea another and also i'm lovejoy argued that is

a males collecting the food and sharing it with a attentional mates. an idea that may be more lasting power would be about energetics, moving on to legs, yes we are slow that were energetic and the very efficient. one of the best ways to explain this is that talk about these ideas and he said that in order to lose a pound of weight you would have to walk about 70 miles. because we're too good at it. were to energetically efficient. so now, if you're losing weight if you're early but if you need to get enough food to survive and maybe there's not a lot of landscape, those individuals are moving away that's energetically efficient they might survive better. and so that is an idea as well.

there are lots and lots of hypotheses and we still don't handle on it and that is okay. they're going to be plenty of things of the new discoveries they're going to allow us to go back and revisit some of these ideas and retest them and really the issue for me is not figuring out which one is right, it is beginning to narrow that last down t and eliminate the ones tt are clearly clearly and clearly wrong that the way science works by refuting ideas rather than proving them. kate: if that's right, so we don't know yet why this evolved but we do have a lot more information than we used to read what the timeframe in which involved. so maybe we can talk about some of the discoveries that have

really kind of allowed you and your colleagues to start to piece together when this all happened. and what it might've evolved from. and where it took us pretty. jeremy: so a lot of folks listening will probably know about lucy, 1970s discovered and lucy is a magnificent skeleton. and the original was in ethiopia of course but not only was lucy, there were footprints. i was in tanzania where i do some of my research as well. that pushed bipedal realism back to about three to half billion years ago so those were remarkably important discovery showing that human life bipedal realism existed three and half million years ago and the genetics that would point towards a common ancestor that we shared with chimpanzees at

about six or 7 million and that the split between the two lineages is probably complete by 6 million years and that is a big gap, there enough million for 6 million, what is going on in that timeframe and in the last 20 years, there have been remarkable wonderful important discoveries that have been made that he spent and begin to piece that story together what is a partial skeleton from ethiopia, fort have billion years old. and another key mythology of the pelvis, and also the foot that would indicate that at least it was occasionally able to move around in two legs when is on the ground but it also has the pronouncing time of the foot and this is an excellent tree climber, long curved fingers a really good tree climber but when it camed down to the groun, the neglect, no it it did not to be could actually move on two

legs. for half million now something that is bipedal and be of further than that, the evidence becomes more controversial and a little more difficult to interpret. so this is a tow boat from a five and half million, or in ethiopia and it matches the shape especially the end of the bone thehe human tow that would push off the ground when you are walking where is a chimpanzee, the two actually curves in the other direction for grabbing. and this has a curvature to it than is marking a site definitely could climb trees in angulation to his base like yours and mine meaning that it would probably have been able to push off the ground it so this is aly cute but that cool possible. it's just a tow that would be nice to have more. it is beautiful one from kenya

and 6 million years old. it was unique about this one, the affair into a chimpanzee, the head with a bald part of the hip joint, very similar but look how short the neck is the ten. and a long neck on this fossil prettyec and what that would do, similar to what i'm talking utterly repositioning those said muscles so you balance on a single egg by drawing those muscles further from the hip coming in making it more efficient. and we think about anatomy, is evidence for biped ♪ ♪ lotion. and we go back further than that, 7 million years and there is this remarkable stone that was discovered in chad and is very controversial and the researchers who found it in person turbid ticket argued that the whole of the base of the

school next the brain was in humanlike position and therefore, this creature would've been able to w hold himself upright. and maybe evenel walk on two le. we don't walk with her head and so i would like to see the fossils from other parts of the body and there is a femur now that is been published i one team and then another team has a pre- printout and they come to completely different conclusions and whether this is no bright walker or not enemy, if you converge on that common asked mr. the chimpanzees, you'll get something that is not quite like any of the living apes. it's a fabulous combination and maybe a frustrating accommodation of anatomies that are difficult to interpret. it is kind of what you might

expect in a common ancestor. kate: do you think that this aimer looks like that of a biped or . jeremy: have not been able to you know, like to talk about fossils that i was able to see this is not a fossil that have been able to see myself. however, there even older fossils now that we don't have much from nine or 10 million years ago but there's this new discovery from a site in germany and germany sort of my sound, surprising to some of the folks listening to because we been talking about stuff in africa but in the, apes expanded all rather mediterranean but is today the mediterranean were living in force in southern europe so we find in france and italy and greeceur and germany d

turkey and it also in hungry end of this new fossil from a creature called the nevyas, from 11 to half years, it looks like it is very upright and to me, that's an interesting find because there were still trying to find figure this outcome is one of the top hottest topics in our field right now. with theop body foreman for whih they have evolved. there are a lot of t-shirts and bumper stickers that would suggest attempt turn into a human. chimpanzees are - not our ancestors, there are cousins in the common ancestor is innate that we branch from but so did chaps and chimps evolved as well pretty so it is not given the common ancestor was out a walker and, some of the fossils that were finding in those deposits

might indicate in the common ancestor was actually more upright in the trees and the knuckle walking and could be more derived a form of locomotion. her play researchers in my colleagues that would disagree with that predict the knuckle walking is the form for which biped involved in the have compelling cases for that. we need for fossils to figure this out. kate: is a revolutionary idea. on think about that. so if biped is uniquely common trait,ni and 10 million years, d biped, is a potentially a hominid party. jeremy: i don't think so with don't think the timing is right and i think that in genetic data so very clearly when they were branching having said that, there are vague error bars around these divergent states

but i think you raise an important point in our field has always operated under the assumption that if you find anything shows characteristics of upright locomotion, that it is automatically by definition, a hominid meaning is an ancestor relative of us, would be more closely related to us that any of the other apes. and i think that assumption is on the table as maybe not being 100 percent correct because if you bad, apes experimenting with different forms ofne locomotion including upright apes in the trees navigating in the trees, they might have some anatomies that look more human like for instance, the tibia in some

ways, not an always good in some ways looks very much like lucy's. and i think that is telling us about like positioning's, not necessarily weight-bearing on terrestrial bipedal leg but an animal that is in the trees and moving with and this biped and you sometimes i do, spider monkeys will do this. but it would mean that finding evidence for biped, may not be enough anymore to claim, and status and this going be fun ratedd as we find more fossils from that, five and six and seven and eight and nine and 10 million time period, we will see lots of experience going on with locomotion. and lots of places where biped may have been i said tempted but

may have evolved and then that animal died out, it just was not a selective adventitious form of locomotion as ay habitat in a habitat changed. it will be fun read. kate: definitely so we talked a little bit about the fossil records showing about the origin of biped and you mentioned this briefly, there are other kinds of data we can look at to sort of study the emergence of this kind of locomotion and so you mentioned which i always wanted to visit the sort of most iconic site and even just thinking about it gives me chills. so there, your scene behave your

of an animal. and what does that tell us about the evolution of biped and at that point of time which is about 6 million compared to what you know about it going get back to like . jeremy: biped to . zero, it's a really good biped and those footprints, yes, it's a magical. the place is just amazing. there are footprints in all of these ash deposits that are eroding out of the hillside and like you said, the bones, fossilized bones, the fossils

these wonderful we can squeeze information home with them and tell stories about winter ancestors were like from these bones the footprints are alive and they are telling you about this moment in time the life of a living and breathing and individual who is a lot like as. andus a lot of the recent biomechanical work that is been done on footprints, is telling a story very human like biped it's a be a lot like us. it is not hunched over crouched down. becca groucho marx walker jim pansy movement on two legs, and from a distance, it would look like you and i walking. and if you could put it on a treadmill, he would pick up some subtle differences probably that is a fun thing to think about because you can't ever put them on a treadmill but from the footprints and from the bones, it looks like they're not

pushing off the big toe on is much as we do and the arches are flatter than ours our and their like shorter. and there maybe not extending at the hip but is much as we do when we walk with those differences are so full rated but one of the really i think amazing discoveries the last ten years is that we often will think of biped evolution in a linear way. even just ended talking about it a little bit ago and what we see instead are different forms of biped evolving in different species. and so the same time that lucy and her species were around, and making those humanlike footprints, there was another species that had a divergent big toe that was in ethiopia not far from where lucy was found climbing trees and walking in a

bio mechanically. different kind of way. this was a fabulous discovery. this was in ethiopia in 2009. as for the these different forms of walking and coexisting. living on me, the skeleton here was discovered by lee berger and actually the first case by his nine -year-old son. this was in south africa. also in 2009, that's when they were published in the discovery in 2008. at work in the fight in the leg of the skeleton when he first started to work on it, to me that's what was i studied it the foot and ankle and leg in a just finished myst phd. unseen all of these fossils and to me there was variation but not functional meaning variation in everything was so different from anything i'd ever seen,

with his heel and ankle and knee. an aspect of the pip in the lower back that we hypothesize that walked in a very different kind of way that lucy and her kind and what is needed is that this carries right up until - and even on the doorstep of homo sapiens, you have neanderthals in europe and also in asia and the islands, you of others. in the right and south africa's this brand-new species, called. [inaudible]. so there are all these different species and populations coexisting and some of them we interbred with and some of them i don't think we probably did the from the foot bones in the leg bones it looks to me like many of them walked in these bio mechanically slightly different

ways and flavors of walking. all talk of the thinking about jumping in a time machine and going backg to the base tims and you see these different kind is advice, different species of our ancestors. they not only look different but it may be begin sort of these different things but they walked in slightly different ways. kate: that is a great experimentation. not just something this is happened when is planet of the apes. but right up until virtually yesterday. in geological terms. jeremy: that's right and it's amazing when i was in grad school at the university of michigan, the story very much was, right up to the homo sapiens in the what we do in the intervals this will be all argued about, really different

species or with a part of our heritage. and now, so to me, studying right walking, it wasn't really interesting. we already had evolved so let's go back. and so it's really interesting, there's a lot going on. kate: so if we go back to the earliest information we have on the marquis more like we do, it is interesting that the first are the oldest known stone tools are just a few hundred thousand years younger than those footprints. some are getting open closer to when darwin was talking about essentially. i'm just wondering sort of like how you see things aligning

their, could it be that biped 2.0 is what frees the hand to start to do stuff like making stone tools. jeremy: i think the possibility isis there. and this was darwin's idea about the biped origins that he also incorporated brain size which we know now it's probably not part of the story that i with that, does happen later. let your absolutely right, that he go back to the 1970s and 1980s, we have footprints of three . six in the oldest stone tools as one - eight it looks like darwin was wrong. the two were just chronologically not aligning it and then there were stone tools that are 2.6. were getting closer read and

humanlikeno biped to get pushbak thanks to tibia, discovered by a person, 4.2 million years old and is very humanlike and i would love to see what the rest of thehe creature looks like. leviticus and honestly, is the same i hope some of my expectation a given a remarkable colleagues are up writing these fossils. i love being out there looking for them. but they are much better at finding them. ihe think about the person who made extraordinary discoveries in eastern africa in the last decade or so h the last two decades, so knowing more about that creature i thank you so going to be appointed to put back to your point, when you have at least reports of the three-point $3m and they are

controversial but at the same time, three-point $3m, to me behaviorally you don't see any reason why they wouldn't be making the stone tools there walking like us there's a slight brain enlargement by 20 percent increase in brain size and new discovery on the basis of the juvenile skeleton that shows that they had slowed down brain growth and that is tied in mammals to learning and relying heavily on learning and this is a horrible idea for a biped but also something this would be heavily predated the pond and the environment coming want to speed up your growth rather than slow it down. plenty of more than happy to eat them but the selection slowed the frame growth, causing story

of heavy reliance on morning and morning coat - might have been involved in learning how to make stone tools but also the story of buffering and social buffering that honey were off right you survive in a landscape like that when you are slow and how do picked up by the leopard all of the time. is that you look out for each other you have each other's backs and so i think we are built into biped locomotion and is simply is not going to be an evolutionary success mostly happens in some things that is either superfast, like an ostrich or the super social and even compassionate and empathetic like we are read. kate: i thought that was fascinating point you made in the book where you start a face

talking about the early ideas of linking biped to violent behaviors and home and ends and to now you making the argument that actually could never worked if our ancestors didn't have the capacity for empathy and cooperation. >> i i think so, i think that ia of uprightness and the hands-on just for tools but for weapons is still part of the popular culture and we have all seen 2001 space odyssey, the beginning was the weapons had that has its intellectual roots back to raymond darr who discovered the first one it just over my shoulder here from this wonderful little console but

later in his career in the 1940s, post-world war ii he worked at a site where he discovered the bones had been smashed any formulate a hypothesis that the homonyms themselves had been doing this that we were these bloodthirsty killer apes and that idea has had roots and is still sort of again part of popular culture even though we know now those bones were smashed up because the hyenas, was not us so the science is refuted that idea but it is still part of how we think about ourselves and instead, i draw attention to apostle like this discovered in the 70s by a team in kenya and this is a leggett bone, upper leg bone in the early hominid, short of 2 million years old, long neck so we can tell it's up word

walker but the cool thing about this possible, the amazing thing about this fossil is ahead a healed fracture so this year, this bulged bone sticking out of the side of the femur, that the heel fracture and think about breaking your femur, 2 million years ago, the hospitals or doctors or fire or shelter, and break your leg. but you heal, you survive, that can't happen unless other individuals are helping you out is just 2 million, in fact lucy species, there is a skeleton, the second skeleton known as captain new ♪ ♪ and he is about three and half million years old we think it is a large male and he is a healed ankle fracture so i can be stepped in a hole or fell out of a tree or something happened it and he broke his ankle printed if you're a zebra you break your

ankle, that's not a good situation in which are still able to get from point a and two-point be if your three legs but if your biped and you break your ankle, your already slow, and i are hopping around the landscape i don't see how you survive and yet this is a healed fracture to the individual did survive and again, it is connected in these vulnerabilities that we have as bipeds but then, the fact that we have injuries and make us particularly feeble if as bipeds, is explainable only if e and continue to be compassionate us and generous with one another. >> fascinating and i know there are questions from the audience.

so i will turn it over to her greatest mckay and thank you and i had not heard that about that the heel or the eagle field, i did know is that far back. sue and that was the discovery it was discovered in 2010. okay, 11 years ago now but still, is indication of just how rapidly my colleagues are finding these fossils and putting them out there, each of these fossils has this amazing story tond tell about why we are the way we are today. so it's easy for one to get overlooked and that's a cool fossil that would definitely didn't get the attention it deserved it. >> well, clicking through the questions again, i feel like a memory that i have asserted that

the last i've heard your present evidence about the idea that will sorry, that's awesome. nice to know we can be nicer than we think. very reassuring. so we have a question. so if you were able to change human anatomy and make five for your honest, what would you would just printed. >> so first, the foot is a disaster.it so the foot is sort of like evolutions example of a good try. you did your best foot happen here is you converted an 8-foot into something that needs to be

rigid. so yes there are moments of flexibility but also pushoff the ground in a rigid way so we have the same 26 bones in our foot that chimpanzees do so imagine you're trying to create something from scratch and it needs to be able to contact the ground, absorb elastic energy and then kick off the ground into your next step you make it out of 26 parts, you failed engineering. it just would not happen. so look at this, now there you go. so here is a foot from an ostrich predict and what is a happened over the course of evolution, bird evolution is that the bones that make up their ankle and foot have fused together into a single rigid structure that is opposed of inf 26, it is about eight or so in the foot of an ostrich in this ends up looking a lot like the

blade prosthetics that a lot of parents would use news with great effect and can run very fast.as and so yeah, i would totally change the foot. now the back is next, that's a bit of a mess as well. but they were more the foot so that is the first place that i would go read then he is a disaster as well ballistic with a foot. or[laughter] >> branching off of that there's another question, do you think is it possible for biped for them to evolver improve. so what this would be representative of what it would

be. it. jeremy: that's a great question the kind of thing but i like to talk to my students about. i don't think so. if you look at all of these different sort of thought body forms that existed, i don't see the human body today, homo odsapiens as having some advante over some of those others. with some it looks like some are so maybe your range was not as large but i certainly don't think that we have reached some pinnacle of biped locomotion and again, i would much rather have the skeleton of an ostrich if i wanted to get from point a to point b onav two legs. or t rex for that matter. and even, if you look back in the past, one of the fun things that they had to research writing this book, where biped animals that have long gone extinct. for instance, doese a crocodile

known as artifacts discovered in north carolina by lindsay who is paleoanthropologist, at the museum of north carolina, sorry. she reconstructed the gate of this ancient crocodile is being up on two legs at least occasionally so imagine it a 9-foot tall crocodile would be able to sprint. that would be horrifying. and yes, i find it fascinating is that didn't have evolutionary legs. what happened to the crocodiles read and all fours, and ambush hunters being bipedal is not evolutionary successful ultimately. the quad was museum in dinosaurs as well the earliest dinosaurs were bipedal. and pat a sorensen others, they

evolved from biped. so, it seems to pop up occasionally with biped and honestly, failed. lein either converted to quad or no lineage. >> so could you talk with us about this may be in conversation but a reminder for like, so biped gradually, what is the time span, how many millions was it, time span really predict what we don't know in demands upon the body form of that common ancestor what it looked like because there was a knuckle walker, if t is the ancestral trait and to chimpanzees have retained it t

guerrillas of retained it, then you would have to have an intense rapid natural selection to go from a knuckle walking common ancestor to something that g is not just getting pickd off by leopards because it's hunched over they cannot move either quickly or efficiently. so this circumstance, i perceive is happening incredibly fast. for, have an incredibly slowly if the common ancestor is something that is more like a large like thing of than treason moving on two legs and then i was there is an environmental change and you can pass the forests, he has to move across the landscape on two likely already has a body form to do that predict that is not a new look hundred locomotion, just in a new setting. in that case, it would be very

agile and what we would be looking for, i think our anatomy center on biped been something a terrestrial biped predict not even thought what that would be as a field. how do we distinguish between something walking on two legs on the ground, versus something moving on two legs. trees were compliance of the force will be different. you probably wouldn't have have to have the because you're only running their hands. to inhabit of pelvic tilt problem. so would not really grappled with us in the field. >> i would think that in contemplating these different scenarios there would be fun to be to sort of fall into a trap about some of the 500 no, maybe by the time, for the layman it

seems like that would be a pretty easy trap to fall into. jeremy:as i think it is probably happened gradually anything probably not one explanation that was a host of things in her efforts to search and maybe the answer is pretty wrongheaded. however, to have a population in a variation in certain individuals three more than others and they end up having more food and reproductive opportunities and off you go. just try to figure out what it is to allow those individuals those more opportunities and more food and there are other scholars that think this was more lamarckian prayed that this

was in a has been written about this. the biped emerged as a mean that itit was just a cool thing to d. and that chimpanzees and gorillas occasionally move on two legs and if that sort of became for some reason, the pad and thatoc population, and you n have four more individuals, and because the bone is elastic to an extent, he might get some of the anatomies, because you inheritedd them genetically but because you acquired them through your life. so the best example of this is a newborn, your femur is straight. matthew start toddling around, your femur begins to angle in a become locked need. were not born that way so when

you find a femur as was found in 1933 that has an angle to it, tells us this individual had to a whopping two legs. because there's no other way to get the angle. so this combination of the anatomy or warmer than the ones that you acquire, the blended together your muscular skeletal system that allows you to move into legs. kate: thank you. so we have matthew asking what circumstances are making it easier to find more fossils today. jeremy:os great question matthe, great question so like any science, you build on the work of previous generations there were lots of false starts and have an mistake made and you learn from the mistakes of predecessors naming sunday,

there's also a lotot of technicl logical advances having princes in south africa, one of the reasons i'm a college have been able to find as many fossils i says has is by using satellite imagery and looking at clusters of trees that grow. near on that when sleepwalking is really hard to see these caves. from the top down, you can see the much better rate of one of the things that is happening. i would also argue special in eastern africa was unusual in this and that instead of doing pershing science dropping into these places and spinning a couple of weeks and going back to the united states and western europe, loans were now incredible fossil discoveries being done by individuals from thoseth countries.

, kenya and also in many many other folks. so kate, i'm curious what you think about then what you think we are getting this discoveries. kate: also wonder if people are thinking about this is what led into the cradle of humankind which was already really well explored. and they found these amazing things. so maybe we all need to look at things that didn't really had any more thought for or when a look at yet and going there with fresh i and fresh outlook. jeremy: i agree is true in the assumption that we had already

been made, contemporary date for the last ten years, i have just been astounded by the number of fossils and the like were getting more than what we already knew about. it is to some degree but also finding things that i don't think any of us could have predicted. i would not have predicted any of them. so it has been is really wonderful awakening in her field. in a sense of humility that there's a lot out there for us to discover and a lot of ideas are going to end up being wrong. it's a okay as long as we are following the evidence. then it is okay to have an idea. at this new fossil

show that i was wrong oh well. >> i think we leave it there pretty were about out of time and they both of you so much. jeremy and kate, this is fantastic and thank you for joining us. in the learn more about this incredible book. it posted a link in a chat. there's also link and thank you so much for tuning in. stay safe and have a lovely night and thank you again to both of you. it. >> former undersecretary for science and the department of energy during the obama administration argued that climate science is not settled pretty is a portion of that conversation pretty. >> about 2005, up until the time i left the government, is working to develop and

demonstrate technologies. in 2013, i was asked by the american physical society which was professional societies of represents 50000 physicists to bring a refresh of the statement on climate change. the 2007 i issued a statement to gate under great controversy. and you know that's a red flag and. [inaudible]. i felt rather than many professionals, any statements to establish what they say, i thought as physicists we should have a deeper look at the issue so we had five physicists on the panel, and initially, three

scientists i think all of them actually in one way or the other, and also skeptical scientist pretty. [inaudible]. we do this for a day or so. again there are things here with that we don't understand. and it's very important and i was also surprised by how those shortfalls in time that i had been studying the matter and so it was the substance of the signs but also how clearly it had been communicated to the literate public and pretty. >> you watch the rest of this program a booktv.org, use the search box at the top of the page to look for stephen the title of his book, unsettled. >> phd in physics at the university of