Become a sustaining member of the Commonwealth Club for just $10 a month. Good evening, everybody, and welcome to tonight's event hosted by the Leakey Foundation, the California Academy of Sciences and the Commonwealth Club. Thank you for hosting.
So I'm Shannon Bennett. I'm the chief of science and the Harry and Diana, dean of science and research collections at the California Academy of Science. And it's really my honor to be here to welcome you tonight.
So the three organizations that are co-hosting this event really share a common purpose in the promotion of collaboration, learning and making a positive impact, all in the recognition that science is critically important to achieve these goals. So I would love to have you enjoy more and learn more about our organizations. I'd like to express to you how thrilled we are when we can come together and meet our common purpose in such a wonderful way as work. You're going to soon see tonight. And we do have some tables that highlight some of the features of our organizations. And we've also shared some links that you can explore online at your leisure.
So please enjoy and learn more about us, and I hope you have a wonderful evening. But before we get started, I want to first invite you to join me in giving thanks and heartfelt greetings to the all the indigenous caretakers of this land, past, present and future, whose sophisticated ecological knowledge and management practices have contributed critically to the biodiversity, the tremendous biodiversity of what we now call California and that we are enjoying today. Thank you. Yeah. So I have a couple of housekeeping items before we get started. First of all, if you are here in person, we kindly ask you to put your cell phones on on silent mode or on do not disturb mode.
And I always have to take my note and check it just to be sure if. Also, if you have questions for Dr. Ward and I hope you have many there are question cards on your seat. Please submit those throughout the talk as you feel inspired and will collect them and then ask them up here on stage after the presentation. I would like now to move on to our our presentation.
So first I want to start by introducing Dr. Zoriah Lems again, who is a dear colleague of mine and also a dear friend. And so I'm a little moved to be able to to be introducing his or I. So Zoriah is the Donald N Pritzker, Professor of Organismal Biology and Anatomy at the University of Chicago.
He's also a member of the Leakey Foundation's Science Executive Committee, and he is a former curator at the California Academy of Sciences, as well as a current fellow. So with that, Sara, please come in. Thank you, Shannon.
I'm a bit overwhelmed. I would say, because I find myself between the California Academy of Sciences, where I spent eight years as a curator of anthropology and the Leakey Foundation, which supports the research that I'm so passionate about. Again, on my right or left is Carol, who is one of the most inspiring scientists. And then Shannon, also an inspiring scientist, but also my former boss, my dean. So and third, I am back in San Francisco, where again, I spent eight years as a scientist. I'm very excited and moved also.
Shannon, thank you so tonight we are pleased to present this year's Gordon P Getty Award for Multidisciplinary Research and whatever that entails, I'll let you figure it out. People at the Leakey Foundation know a lot sometimes about human origins, and I do like Don De La would tell you stories about both periods reporting. Sometimes he's ahead of me. I remember sometimes.
So thank you for your support then. The Legacy Foundation really has made great and incredible contribution to what we do and what we are interested in as scientists. The award is a work marks a special milestone as we celebrate the 50th anniversary of Mr. Gordon Gates leadership of the liquefied. You note I said 50 years.
How many of you have done that? Let's all get inspired by that. Mr. Getty support has contributed four to funding thousands of research projects that have changed our understanding of humanity, and we are really grateful for his contributions. Thank you, Mr. Good.
And then my friend Carol. Dr. Carol Work, officially speaking, is the curator is professor of pathology and Anatomical Sciences at the University of Missouri and is a recipient of this year's award. Her work explores the evolution of hand and foot function in African apes, humans and our ancestors. Actually, it's not true.
It's more than that. This is probably the project that is just being funded and supported by this award. Care on his way more than that. Her innovative research is advancing our understanding of what makes us human, not only in the field, but also through her efforts to share her work with the public.
And it's not just that. Also, some of her work on competitive living primates through her lab work in the tools that she does in museums around the world. We are honored, therefore, to recognize Dr.
Ward's outstanding work, which reflects the highest standards, highest emphasized by me, of scientific excellence. But also many of you don't know. About. Only a month ago, she was elected to be the member of a number of the American Academy of Arts and Sciences. Welcome to the club. The first president of this country, George Washington, was a member of this association.
To give you just some idea. And Oprah Winfrey was. But I'll tell the story at the end. And this is my last.
Many of you think maybe that I was trained in the U.S. It's not true. I was trained at the University of Paris, Sorbonne, and I wrote my Ph.D.
in French. And one day I was having drinks When I was in graduate school with a few graduate students, three ladies. And they were debating as to how we can do fieldwork, research and also raise a family. It was a very heated debate. We also had a couple of drinks and I would just listening as you know, I don't necessarily have that challenge in. One of them said, well, girls don't fight. It's doable.
And one girl says, How do you do it, Carol? What did it just that. And I only told Carol the story only yesterday. So thank you for raising your family and telling us about humanity. Combined, I think, was that we are honored to that.
I would like to invite Carol Ward to tell her about her work and inspire us, as she always does. Thank you, Carol. I'd like to say thank you again to all of you for being here and spending your Friday night hearing about something that I am super passionate about. And I just want to start again by thanking the foundation, thanking Mr. Getty for all of his 50 years of work with the foundation.
I don't know if any of you who are not associated realize the impact that the foundation has had on many of us. I think there's probably not a person who studies human origins who have not benefited from the Leakey Foundation. In fact, it's a particular honor for me because my very first research grant was from the Leakey Foundation back a couple of years ago now, and it started me on the path that led me here today. And I have been funded several times over the years. And you'll see throughout the presentation that I'll be signing some of the research that the Leakey Foundation has contributed.
And I am one of the many thousands of people that have benefited over these not just 50 years of Mr. Getty's involvement with the foundation, but of the whole foundation all. So it is really exciting for me to be here, and I think all of us in the room are here because we share a passion and a desire to understand who we are, where we came from, how we got to be this amazing and biologically unusual species. These are just some depictions of some artists have made us some of our earliest ancestors over the years. But when you see pictures like this, they're encapsulating a lot of research by a lot of people that led us to our hypotheses or ideas about what our earliest ancestors may have been like. And so how do we learn about our ancestors? Well, the only source of evidence we have for when the different key features of who we are appeared is the fossil record.
The fossil record tells us what evolved when and with what. For example, over 100 years ago there was a guy named Charles Darwin. Some of you may have heard of a pretty bright guy. And Charles Darwin had the idea that what really makes us unique is our big brains and our language and our culture and so forth. And so that must be what set our lineage apart from our forebears initially. But only 98 years ago there was this little skull found in South Africa, and this little skull was clearly a human relative.
And it doesn't have a big brain and has a brain that's pretty much the size of an ape. It didn't look particularly humanlike, but it has a sort of a short face like we do. And importantly, it looked like the head set up on top of the spine. So was an upright biped.
And this little skull really upended our ideas of how we evolved. We know that big brains and tools and bipedal locomotion didn't evolve at the same time. Things happened differently. And the the anatomist that found this, Raymond Dart, named this creature Australopithecus, which means Southern Ape, because it was found in South Africa and Australopithecus is I'll talk a lot about it tonight. You'll hear more about it. But we now just not just have one of these these skulls, but there have been many teams over these last 98 years finding more and more fossils.
This happened to me, some of us out in eastern Africa looking for fossils. And we now have hundreds or even thousands of fossils attributed to our fossil ancestors. And these have given us a great idea about the trajectory of changes that led us to where we are today. But equally important to finding fossils is interpreting them. What do we do when we get these fossils? How do we make sense of them? How do we unlock their secrets and tell what it is that they actually reveal about human evolution? And this is where the work of the Leakey Foundation is so important to understand what these fossils are telling us.
We need to figure out the anatomy of what they're what they're telling us, what their functional signals might be. And we need to put this together with information about behavior of our living relatives and genetics and evidence of our own behavior and so forth, to put together a picture of our evolutionary past. And that's why the work of the foundation is so important, because it funds all of these aspects of the endeavors that led us to where we are in terms of our knowledge now. Now, Australopithecus isn't just a skull.
This collection of up to eight or nine species, depending on which one of you which one of us you ask on any particular day. But there are multiple different species. But all of them, when you look at this Australopithecus here in the middle compared to a chimpanzee in a human, you look and you see there's no big brain like you see on the human here. But you also don't have the big projecting canines like you see in an ape. But what's really distinctive about all of these species is they have these huge faces and teeth and jaws and this really intensive adaptation for eating not just fruits like the chimpanzee, but whatever they ran across on the environment.
And so this sort of intensive chewing adaptation thank you is really what marks this species. But what we it doesn't look particularly humanlike. What was really distinctive about Australopithecus is the way that they moved around the world.
And this is really what is most notable about telling us that these are, in fact, our fossil relatives. From the neck down, we stand up and walk around on two feet in a way that no other species on earth has ever done. And we can see Lucy over here on the right, sort of the poster child for human evolution. Her skeleton, in all intents and purposes, is very much like our own or some of our more recent fossil relatives, like the members of the genus Homo.
So it's walking upright on two feet. That's really distinctive about even Australopithecus. And just in case you think there aren't many fossils, these are now some of the associated skeletons that we have, along with many, many, many, many other isolated bones and teeth from which we can extract information about our past. So Australopithecus being bipedal, I won't say what to many of the details here is seen in, for example, the knee.
This is a thigh bone we are not need. So when we stand on one foot our feet, the center of gravity is right of our foot and we can walk without falling over. We have a pelvis that's rearranged that we see in Australopithecus to enable the muscles to balance us from side to side. When we walk around on one foot at a time. We have spines of Australopithecus vertebral columns that share the segmentation pattern, the curvatures that allow us to stand fully upright and would have allowed Australopithecus to do the same. We have evidence from the foot humans of the only primates that lack a grasping big toe.
And we have fossils that show us this. We justify it with arches in them that allow us to walk very effectively. And Australopithecus had this, too.
And if you don't believe the bones, there are even footprints that are over three and a half million years old that show this distinctive human pattern. These and more lines of evidence tell us that really Australopithecus is definitely much more like us than it was like a living ape and definitely a fossil relative and would have stood and had a body shape pretty much like us. So a few little details, a longer arms, little marker, fingers, maybe a little different shoulders and so forth, but really fundamentally humanlike and being bipedal. And so a lot of us worry about bipedal and how important this is for the origins of our branch of the family tree, the Australopithecus and human clade, as we would call it. And so the very, very first Australopithecus, we have is called an immense.
It was found by Meave Link in her team in the nineties and annum as the Turkana people's word for Lake found near Lake Turkana and an immense this is about 4.2 million years old. And if you look at this diagram here, you see there's an explosion of species of hominids after this time. But Anna mensah says the beginning of this branch of the family tree. Now, there are some older fossil relatives of Australopithecus in us. They're a little less complete. I'm not going to talk about them too much today.
But the beginning of Australopithecus starts 4.2 million years ago. So the question is, was Australopithecus bipedal? If you look at a human like this is Eliot Chokwe, the marathon runner. You can see that he, like the Australopithecus here, look like they have a leg, a tibia from the needy ankle that's straight up and down because our knees right over our feet. The chimpanzee over here as an angle to its tibia because that's associated sort of this bow legged appearance, lets them turn their feet in and climb on branches and so forth. And I promise not too many numbers tonight, but you can measure this very simply and you can see that an immense is an all those other Australopithecus, all those other fossil hominids there looked just like humans. Tibia straight up and down.
So we know that 4.2 million years ago, our ancestors or our relatives were already bipedal. Now, if you pick up, you take an anthropology class and you pick up a textbook, you'll read that this strange, heavy chewing adaptation of Australopithecus, this is something that occurred that allowed them to move into open areas. Now, the time period right before this sort of five, 8 million years ago, the Earth was expressing climate change.
There was a cooling and drying forests were shrinking, particularly in eastern Africa, where these animals lived, and they're finding themselves in the open country. And so the story goes in order to find this new sorts of diet sources of food and so forth, they were changing their diet and this led them to move further and further into the open country and eventually become bipedal. So if an immense this was bipedal, what about its dietary adaptations? What was it eating? Well, we know that canapé that were the first animals found is a beginning of a lineage that evolves into what we call afarensis, which is Lucy's species, or it's all one species, depending on who you ask or what review articles you read. Right. That's fine. That's all good.
But what you can see is the jaws of animals and afarensis here are different. And you see that the Afarensis jaws more V-shaped. The front is pulled together, the chin is a little bit steeper. And we think that this is a change of shape that allowed afarensis the later populations to eat, to be better and better at chewing harder foods.
So there seems to be bipedal ality being established by 4.2. But still this dietary evolution going on now, are we right? Well, here's where analysis comes in and here's where new ways to analyze fossils are really important. Zare And I and some of our colleagues are actually capitalizing on engineering approaches where you can use computer modeling to load different jaws and subject them to different forces and see how they respond to try to test this hypothesis.
This work is still in progress, but we're hopeful that Skinner and his colleagues have been able to use high resolution micro CT scanning to look inside teeth and look at the thickness of the enamel cap on the teeth. The thicker the enamel cap is, the longer it takes to wear down so you can eat tougher things. And if you look in the red circle, there, you see that animal is actually a thinner enamel than later hominids. So that seems to indicate that there was changes in dietary behavior as well.
Lots of clever chemists can look at the isotope isotopes of carbon that are left in the teeth and the teeth are growing. These are products of plant photosynthesis. And as you eat plants, you incorporate this carbon into yourself and it shows up in the teeth and you can see the animal. This is down at the bottom of this graph. The details aren't too important. And so that would have been specialized more in just plant based resources, whereas you move up through time to the right here and you see a much greater breadth of plant base and or tree based and grass based types of plants they would have been eating.
So a broadening of the kinds of things they were choosing. So that really does seem to be dietary evolution going on in this first million years. And so it might be that bipedalism, in fact, enabled this change in dietary evolution that happens later on. But the bipedal idea was pretty well established first. So to me, this is a long winded way of saying it's transition to this strange form of locomotion that really defines the beginning of this lineage.
And if we want to understand how this began, that's where we should start looking. So if we try to figure out where we came from, where did by Fidelity come from? And all we have is the living world, we can look at all the humanoids, which is our word for this kind of animal living in the world today. And they're all basically pretty similar sorts of animals, except for one. I'll let you figure out which one I'm talking about. And so these are all animals that tend to spend their time up in the trees. They tend to use all four hands, if you will, hands and feet to move about.
They hold their bodies upright. They're big, long, powerful arms and big, long fingers and a bunch of other adaptations, short legs and short little bodies that enable them to move effectively around the trees. And so you can see how they do this here. And so it seems natural to assume that our ancestor that we, the last common ancestor we shared with the chimpanzee might have been pretty similar to some of the great apes we see living today.
And this is really significant when we think about locomotion, because when these animals come down to the ground, especially the great apes, they're so big and they have such big, heavy upper bodies and stiff backs and so forth that they use a peculiar form of walking on their knuckles when they're on the ground. And chimps and gorillas spend a lot of time on the ground, moving knuckle walking. So this would give us one idea of maybe what our ancestry might have been like if we only looked at living animals. But we have a fossil record. And so while it's sort of most parsimonious or simplistic to come to that conclusion, looking at modern things, it's maybe not the case.
We know that back maybe 20, 25 million years ago, when the earliest apes first appeared, they walked on all fours on top of the branches and we have dozens and dozens of species of apes. After this time in the fossil record. What we have today is only a small helping of what we had in the past and I won't go through all these. Thank goodness for all of you. But the bottom line here, the important story is none of them are as specialized as their living relatives in terms of how they would have moved about the world, which is one of the defining features of our early ancestors. So I'm going to talk a little bit about on And if any of you were the cattle academy the other day, you've heard some of this, so you can check your phones or your texts for a few minutes here.
Roodepoort Because there's an ape that's probably closely related to the African ape and human clade or group. It lived in Hungary about 10 million years ago, hence the name Ruda Pinkus and I'm excited about because it has a part of the pelvis. And the pelvis is really important because it's part of the whole torso and it also forms part of the hip joint and ankles, anchors the muscles of the lower limb for moving around. So it's a lot of information packed into one bone. But when you look at this fossil, unfortunately, the fossils don't come usually in nice, neat, complete pieces. They have bits and pieces broken off.
And this is missing most of the top part and most of the middle part, some of the bottom part. So we have to figure out again, how do we pull the information of out from this animal that might tell us what it would have been doing as it moved around? And from that, we turn to laser scanning technology where you can get good surface 3D models and then we can come up with different ways of measuring morphology. The don't rely on landmarks and calipers and traditional measurements that thus old timers like me are used to.
And we're able to put all this together and see what of the case look like. I'm not going to go through all of it. I'll just go through some of the highlights because it makes a point that I'll be getting to as we go.
So when we look at the monkey walking above branches and we have the same thing here, this ape, you see the monkeys holding his body horizontally, it's limbs are sort of tucked in as it moves around, whereas the same thing has to reach all these different directions and all this different support. So it holds its body upright and has really mobile limbs. We can tell the route of Pythias would also have had upright body posture because we could look at the hip joint socket called the Acetabulum and we could see it's expanded or bigger at the top, just like an ape and not like this monkey. My former student, Ashley Hammond, funded by the Leakey Foundation, was able to be defined a very clever way to digitally articulate and put together the thigh bone of the femur and the pelvis and see what the range of motion would have been like at the hip joint and determine that route of pith, I guess, would again have been much more like the ape than it would like the monkey.
So here's a flexible joint upright animal living in the trees, perhaps something like this reconstruction. And that's pretty cool. This has gee, maybe this eight by 10 million years ago is starting to behave more like a modern one. But again, the pelvis is not just hip joint, it's also part of the whole torso. And this actually varies a lot in primates.
Up until a few years ago, this was the all the information we have of how animals are put together, because bones either aren't visible inside an animal or in a in a collection. They're just a bunch of bones in the bottom of a drawer. And so this idea here was put together in really the thirties and forties, and that's the information we have.
So we use CT scans to take cadavers of animals and look at all their bones put together. And it turns out that if you have a good eye and you have any drawing skills, you could do a pretty good job if you want animals look like. But we were able to actually expand our knowledge to a lot of other different kinds of animals. And this is just about a few examples and it enables us to see how this pelvis sort of would have contributed to the whole body shape. So here's our monkeys again, walking up on all fours, moving around very differently from our apes, some of which you've seen before, adding the same thing here. And so the way they move around is actually related to how the body is put together.
So you move it. There we go. And so if you look again at the old Adolf Schulz, old drawings here, you can see monkeys have a very long, thin, flexible torso that allows them to move when they're running and leaping and walking through the trees, whereas the ape has a very long pelvis, a very short lower back, a very stiff spine, and that provides a really stiff anchor to all the muscles of the upper limb that are moving them around the trees. So the short, wide body shape, which you can see in the photos, you maybe didn't need the bones, I don't know, but enables these to move around. So how does the route of the thickest pelvis tell us what kind of body shape route the guest might have had? Well, here's where things get a little bit nerdy here. So over on your right, there's a monkey with that long, that long vertebral column, that short, narrow pelvis contrast it with great apes over here on your right.
So when we look at the root of pelvic is pelvis here, it's a little bit broken. It's true, but it actually looks intermediate. So one of the questions as well, if it kind of looks monkey and kind of looks like an ape, does that mean it's moving Kind of like a monkey? Kind of like an ape? Well, no, because as you can see here, the pelvis in parts preserved is almost a dead ringer for Simon.
These smaller apes that move sort of hand over hand through the trees. So if rutabagas doesn't really look like a great ape, did it really behave like a great ape? Well, that's another way. Some of the new ways we have to look at fossils have come into play. Here's a year, a science mag here doing its great hand over hand locomotion.
So is that what it's doing? Well, we use these three TS, these CT scans. My former post-doc, Emily Middleton, who's now an assistant professor at University of Wisconsin in Milwaukee, we put this together and we realize that as you go from a cocker spaniel sized gibbon up to a £300 great ape, the mechanical requirements of supporting your weight over multiple small branches in the trees by multiple limbs and reaching around become exponentially greater. As you get larger and your body shape has to change exponentially as well to satisfy those mechanical demands. So that you can effectively move around in the trees. And if we look at the body size of fruit optics and many of the other apes that also lived in the past, it's about just a little bit bigger than a Simon here.
So what this tells us is Roodepoort thickness was an animal that could have moved around the trees, maybe like a great ape. It just didn't have to be anatomically as specialized just because it wasn't so big. So what does this have to do with anything when we come back to our family tree here we have our original apes walking on all fours, even up through 12 or 15 million years ago. All the apes seem to be walking on all fours. And what this means is that Gibbons and Simons may have evolved this below branch specialization, independently of the great apes and orangutans probably evolved this independently of the African apes and that the gibbons as well.
And that raises a question well what about gorillas and the chimpanzee group? We don't really know. But it raises the question, once we get to around 10 million years ago, these apes are living in Europe and Asia all over the place. There are many species besides Bruder. I just told you about the one. And all of these are starting to behave in a much more modern ape like way, as far as we can tell. But they weren't is anatomically specialized.
So that means that perhaps the last common ancestor of great apes and humans might not have been as anatomically specialized in some ways as we see in great apes. So when we do our traditional there's the old Time-Life drawing that our Leakey Foundation logo was based on. When we assume that evolved from an animal that's very much like a chimpanzee, the big question of human origins always been why did we stand up from all fours? And our I imagine our hypotheses about why this would have happened to see over tall grass or to carry things or whatever it happens to be was based on the assumption that we stood up from all fours. But if we look back at these Miocene fossil apes like Route of Pythias, and we remember that chimpanzees and bonobos have been evolving for just as long as we have, we might get a different idea, a hypothesis, what might have gone on As chimpanzees and gorillas got larger and larger, they would have had to become more anatomically specialized and it would have made to be able to still eat the fruits that they generally rely on. Whereas our ancestors, perhaps as those those environments for opening up as they had to move from trees to trees initially might have moved just like they did in the trees, upright on two feet, which they would have been able to do more easily with a longer, more flexible back and torso.
So maybe the question I think this we should be asking is not why did we stand up from all fours, but why did we never dropped on all fours to begin with? This may be good. It may not be right. We'll see what happens with science moving forward and the project that I'm going to actually end this talk talking about, I think is going to help us get at this question. But right now, I'm going to have a little bit of a pivot. I told you at the beginning of the talk that it's the fossils that are the key to unlocking all of these all of these changes that happen through time. And so one of the things I do is I co-lead a field project to find more fossils in Kenya called the West Turkana Paleo Project.
It's run through the national museums of Kenya, and my co-leaders are Dr. Frederick Shiloh. Monty, who many of you know. He was a spend a long time affiliate of the foundation and received a lot of support. And he's here too. And our colleague Mike Popkin of the University of Arkansas and a phenomenal team and crew that we've been working with for many years to look at sites in Eastern Africa.
And we're going to have a zoom in here. And as we zoom in, you can see the Rift Valley extending through Ethiopia, Kenya and Tanzania. And right in the center there is Lake Turkana, which many of you have heard about. And you can see the sort of lightest colored areas on the map here are mostly fossil river exposures. So the east side of the lake is where the Leakey family has found many, many fossils. We are working on the west side of the lake, all up and down the lake.
We have a number of different projects, including Canopy and other things that we've worked on over the years. But I want to give you a story of one particular fossil find and how it's going to lead me to another big question. I think in terms of human evolution. So the site I'm going to talk about is called Keto, and this is Zoom, which is on Zooming. It's there we go. Well, that was an area economy that's posted here, which is where the Turkana Boy was found.
And this gives you a little bit of an idea where we are and Kenya and what the area looks like. It's pretty far out in the desert. The site of keto is about 1.4 million years old and the Leakey Foundation contributed to this research as well. I want to note that.
And at this site it's a very small site. You've never heard of it before, but we found a metacarpal. These are the bones in the palm of your hand. This is a third metacarpal. So right in the center of your hand and you think, Well, that's not very exciting. Maybe.
But what's really significant about this, which is now behind the Leakey Foundation, so you can't tell. It's okay. I've got another slide coming up. Is that at the bottom of it, there's this little pointy bit called a stylized process.
And I think there's a circle here. And if we move on the style Loyd process is not found in apes, it is not found in Australopithecus, but it is found in Neanderthals and humans. This is a humanlike hand and you're all thinking, Oh, come on, word this a little tiny thing at the bottom, a little tiny bone.
What can it possibly mean? Well, it turns out to be really significant because hands, of course, are critically important for making and using tools and beginning of tool use and making tools is the foundation for all of the technology that's allowing me to stand up and give you this talk today and for you to sit here and listen. So we think a lot about the evolution of the human hand. And to me, after being bipedal, that's the next big question that fascinates me about human evolution. So prior to the discovery of this, we'd seen the style loyd process, which I think is a part of a specialized wrist in humans.
And we thought it was maybe 800,000 years ago or so and some associated with much more sophisticated homo species. But finding this pulls our understanding of the origin of the human hand back over 600,000 years earlier than previously thought. And this is a little bit of a speculation, but it's not too far after in the fossil record. We start seeing actually in tools which are sort of fancy regular tools compared to the tools industries that have come before it. So perhaps this hand is associated with the increasing complexity of stone tool use, which to me also is a indicator of using lots of different objects to make your way through the world.
But is this true? So the theory goes like this, and this is why this delay process may be important. This is a picture here of you can see over on the right here of the second and first and second metacarpal of your thumb and first finger and of the human and the little carpal bones that that support all of those underneath and a human and then a chimpanzee and all the little joints in the bones inside the wrist, the support. These are different. Between these two, you can see the human has a much relatively larger thumb and shorter second metacarpal is shorter palms of our hands than compared to the chimpanzee. And the hypothesis is that the orientation of the joints in the hand reflects the directions of load that are passing across the joints because the joint has to be able to resist the forces.
So it needs to be normal or perpendicular to the loads. And the idea is if you have a big thumb and you're holding things and really grasping and using tools, a lot of the muscle forces will be propagated sort of transversely across the wrist and so that the human wrist will be changed in terms of the shapes, the bones in the orientations in response to these forces compared with an ape. And so using tools, you're going to use this and that third metacarpal style void process is thought to sort of slot into the wrist and be part of this reorganization of the whole wrist. So in self is maybe not the important bit, but it's a part of an or reorganized wrist. And this is a cool idea. I think this is based on the work of my colleague Matt Todd.
Sherry and his advisor Mary Maskey, and it's been great. But we can't see muscles in the fossil record. We don't know if any of this is necessarily true and it's been really challenging to get at this kind of question. People have done clever things. Aaron Re Williams Hietala and colleagues have looked at done force transducers, look at the forces of the human hand when people are doing different things with tools, but we can't do that in fossils. People from Tracy Kmet and Matt Skinner's lab have been looking at the internal structure of bones to try to reconstruct the sort of forces that would have been able to use.
But without the muscles, it's really hard to interpret those data. This is another example of looking at distribution of bones and hands to try to to infer what those would have been passing through the hand. But none of these are direct and this is something I've been thinking about for a long time because of that little fossil. And so at the University of Missouri, I have teamed up with two of my colleagues, Dr. Casey Holliday and Dr. Kevin Middleton, and we were awarded a Leakey Foundation grant to actually look at muscles in the hand and see how they relate to all these changes in the bones. And so what we've done I've done is taken advantage of something.
I've been watching their research for a while. They work on crocodile feeding and dinosaurs and things with this. But you can take a medical CT so if you go to the hospital and you get a CT scan, say this would be of your hand here you can see the bones pretty nicely, but it's all pretty fuzzy. But there are now ways where you can soak cadaveric materials in iodine, which binds to the glycogen of the muscles. And it appears on an X-ray CT scans, which are basically just spinning X-rays.
And with a high enough high resolution scan, you can actually see the tendons and the muscles and the nerves and the vessels inside the hand. And so here's here. I'll show you what it looks like in a moment. But I want to acknowledge to our wonderful students, my current students, Nadin Steer and Mara Fields, who are working on this project, and Edan McIlrath, who has gone on to become a physician but helped us with the early phase of this research. So we're taking this technology and seeing if we can test some of these hypotheses.
So we we do this. This is a chimpanzee in a human hand. These are not the results of our funding.
It turns out it's taking a year or so to actually get the staining and progress of actually going to finally stain our study specimens in a couple of weeks. But these are our pilot data. So this we went down to the University of Texas high resolution computed tomography facility who are expert says, and we we scanned all these after they've been found in iodine. And you can even see all the detail inside the tissues of these two specimens.
And from this, we can get a lot of really great information. So this is a picture of a human hand that one of our students, Spiro Sullivan, made a few years ago. On the right, you can see the CT actual CT images, these stain specimens. We can then use digital technology to segment out and see all of the blobs of muscles and tendons and things of running through the hands.
We can actually see in 3D what's going on. And with high enough resolution, we can use machine learning algorithms, the software to identify each different farcical within the muscles. So these are the actual fast cycles inside each of the muscles. The colors in this particular case reflect the orientation of those fast goals. And this is actually pretty amazing because we can see these all the muscles together before we had this.
You can do dissection and you can pull out one muscle and you can weigh it and measure and do sorts of things, and then you can go on to the next one and it's destructive. This specimen is gone after this. These we can see simultaneously, we can see all kinds of things together at the same time. It's nondestructive. And importantly, we can use this to stay some pretty wifi things about biomechanics and don't go to sleep just yet, but I'm going to go show you some of the kinds of things we can see. So here is our human and our chimp pilot study hands in here. We've just highlighted the muscles, not the tendons or anything else.
So you can see of the thumb muscles which we call thinner, and the muscles of the little finger, which we call hypo thinner. And I think any of you, even if you're not anatomist, can immediately see those differences. And those differences are in three dimensions. Again, the colors indicate dark blue is sort of up and down and the other colors are more side to side orientation. And you can see that the muscles inside these hands are really very different and you can see them all 3D at the same time.
And so what's really cool about this is you can not just make really cool looking slides. I think this is a cool looking slide. You can actually do science with them.
So one of the things we can do, everybody knows when you go to the gym and you have people with really big muscles, they're much stronger. The more muscle physically you have up operating together, the stronger you're going to be. And we can measure the muscle. FAZEKAS Again, using this machine learning algorithms and tell how strong they are.
And details are not super important here. But just for an example, we can also look at the orientation, which direction the muscles are pulling, which is going to tell you how they're going to pull the bones and we can look at where they are relative to the joints. If you're further away from the joints, you have more leverage.
That's when you're in the teeter totter. The big kid has to move in closer to the middle and the little kid has to sit out. In the end, the same thing works for muscles. So, for example, here's opponent's policies, the one that pulls your thumb across your palm, and we can plot the orientation of all this in 3D space. So you can see the human is much, much stronger. And you can see that by just looking at the pictures.
The chimps is much, much smaller. And you can see the orientate is maybe too different, but it's much stronger to take another muscle here. This one happens to be abductor policies. Previs get to use lots of good words.
And this one, the chimpanzee is a little bit stronger than the human. But when you look at the picture in the graph here, you can see that the human muscle is more transverse and it's situated further away from the joint at the base of the thumb. So it's actually going to be capable of producing more force so we can measure not just how strong the muscle is, but all of the mechanics to get what we call moments of how much these things would have worked. Even when we look at the little finger here, there are two muscles here. They're about the same strength in the chimp than the human. But the human you can see is much more transversely oriented.
And humans, actually, you can actually move the edge of your palm by your little finger, a little bit. And that's really important for certain grips of your hand, which you would use for using and making tools, which we do all the time. I'm using it to hold on to these objects. And so when we put all this together, when we get all the information for the forearm muscles, because a lot of your hands move basically like guy wires of four muscles that are up in your forearms.
So we're going to be able to actually quantify the biomechanics of the hand and test the hypotheses about reorientation of the wrist and the evolution of the human hand. So when we do that, we can put it together with the proportions of the hand, with the joint orientations, and we can come back to the fossil record and look at the evolution of the modern of the human hand. We can see what it means if the stylized process story even makes any sense and exactly how maybe the hand is evolved. So we can use those muscle forces to then go back and give us a much more informed understanding of the bones. And I bet you thought I forgot about by Fidelity.
I didn't. We can also go back even further in time and look at the fossil records of not just hominids, but apes as well. And this is about a tiny smattering of what we have in the fossil record. It turns out that there are lots and lots of hand bones in the in the Miocene fossil record that will tell us something about maybe the locomotion of some of those fossil apes. And we could also use this for feet. And feet and hands have been really hard to understand because you have more than 25 bones.
You've got more than a couple of dozen muscles that are operating. Your hands and your feet and apes do, too. And they've been really to study. So we're hoping that we can use this technology to not just get information about the hands and tool use, but also to go back further in time and see how were these fossil apes using their hands and feet as they moved around the trees.
So if we come back to our diagram here, if all of these apes evolved, these sort of superficially similar ways of making their way around the world independently, we might imagine that there are differences are really important, then we know they're different. I'm oversimplifying as they're all similar to imaginable. Come on. But when you look, for example, to the outsides of the pairs of hands and feet of each of these animals, they're really quite different. And when we see a lot of similarity than we can imagine of two animals of similar that they may have inherited, that similarity from a common ancestor, if they're very different, it might indicate that they independently evolved certain things. So given the abundance of foot bonds, in particular in the fossil record, as well as hand bones both from the fossil apes and hominids, we should be able to use this technology to look at we're going to start with African apes and humans to see what the similarities and differences are and to see if they can give us any insight on what that last common ancestor of apes and humans was doing and give us much better insight into the things that make these hominids made these hominids lives and led to us as a species.
So we come back here and you could even see some of these fossil hominins here already using tools. So really hoping that by applying these new ways of studying the modern world and new links to what we can see, the fossils, we can tease even more information out from these fossils, from these ancestors, from these fossil relatives to say, did we evolve from an animal that might have been like a chimp or gorilla? What was that last common ancestor like? Which to me is the fundamental question about the origins of our lineage, and also then take that up in the human evolution to look at that evolution of the hand. How did this progress? Was it related to anything we see in the archeological record? What can we then tell about our development as a lineage and the diversity of the heart of humans and apes and all our fossil relatives that we had in the past? So I'm really excited to get going on this project. And I just do want to reiterate again that the foresight of the Leakey Foundation and the willingness to try out new technologies and look at new ways of things has proved incredibly fruitful over the last more than 50 years. And I'm sure it's going to continue to do this again. And really, the Leakey Foundation underlies pretty much everything I've alluded to or mentioned the way through because it's been underlying all of our ability to do our research.
So what's going to happen in the future? I'm not quite sure. I'm pretty excited about this project. I think it's going to open up all kinds of incredible new doors. I think it's going to address some of our key questions in human evolution and I can't wait to get going.
And I thought of listing everyone I want to acknowledge in one slide, but it would be really tiny font. I couldn't have done any of this without certainly the Leakey Foundation and other funding agencies, museums, curators, collaborators, students, everybody that's made it all possible. So I just want to thank all of you for joining me this evening. I hope we can have a lively discussion afterwards.
I want to thank all of you that are listening in from afar. And I want to thank especially the foundation for the incredible honor of being named the Gordon Peabody Laureate for this year. Thank you all so much. Thank you so much. That was fascinating. I hope it's a little bit mind blowing to me when you present this information about how things have evolved from a state of a generalist to a specialist.
And I wonder you did mention that part of the drive to become specialized is increasing body size. And I wonder what you think would have been the driving force of increasing body size? Oh, I'm sorry. That's my first question. I it's actually in great apes.
Okay. Right. In hominids didn't really become larger until much later, but that's a slightly different story. Great apes are probably and we're not exactly sure, but probably larger than the last common ancestor. Just if you add up all the fossil apes, none of them.
Well, most of them are not quite as large as we see in modern chimpanzees or gorillas. So we're inferring that the ancestor would have probably been smaller and in many lineages of animals over time, you see increases in body size over time, and a lot of different ideas about that may have happened in terms of reproduction and all kinds of other things. I don't know that we have a really good idea or I don't have a really good idea of exactly why that would have happened, but it seems to have happened. So we know that it probably did see, I will just say that a lot of times that somebody wrote this in a card, I'm sorry if I'm present pre getting ahead of you here, but a lot of people say, well, when you go out to find fossils, what hominid, what fossil do you really want to find? What kind of hominid do you want to find? And I say I want to find a fossil chimpanzee because that's what we really need for the answers to answer questions about did they get large? And then we can start answering the questions about why? Which of the hard questions are the fun ones.
So rude epithet guess was smaller than ancient Humans are about the same size. It was probably a little bit smaller. Australopithecus, the Lucy that everybody knows about.
And so they're about the smallest or maybe sort of three and a half, four feet tall. The males maybe about five. Back then, males are much larger than females in general, so probably smaller in body size.
And then obviously we became much larger over time, probably with the origins of the genus Homo or sometime after the origins, these all cool. I will be getting some questions up, but since they haven't come yet, I've got a couple others. Sure, you bet. I think it's fascinating that you can dissect the meaning of the bones in the hands feet. And are you looking for a similar signature in specialization versus generalization, as you see in the arrangement of of the of the torso and that? I think so it's actually amazing how much we don't know about how the human foot function.
There are people that have studied actually great apes, a reasonable amount and they've been able to weigh muscles and measure muscles. But it's hard to put elected roads in animals hands and feet and have them behave naturally. You can't really do the kinds of things that you would want to have the information of. So we're hoping that that this will show us the muscles of the hands and the feet. How are they used differently? It's also very difficult to study hands in living private has been, especially until recently, because hands and feet are small and looking at how an animal's gripping something when you're watching them far away is very hard to see.
Even in a captive setting. It's been challenging to study back on the new technology aspect of things. There are ways you can actually do watch things move in 3D with camera systems now from a distance that are starting to be used, which is really exciting. There are force and pressure plate systems you can use and animals move around and see how much force they're producing, but it still doesn't tell you what about the inside of the hand is doing the work and how that's related to the bone orientation. We have this idea that it should work, but we don't really know and we really don't understand the musculature of feet and how they put together. There are also cool ways of doing what's called musculoskeletal modeling, in which you can actually build computer models and simulations of animals moving in different ways.
And those are fantastic, but they depend on the inputs you put into them. You need accurate bony geometry. That's pretty easy with CT scans and so forth, but the muscles have really been a challenge and we haven't had a way to do it before.
These kinds of technologies came along. And so we're hoping that the information that we get can be said into modeling as we move forward in order to actually see what were the forces, how were they used to put to get together with the behavior. This is very long winded.
Sorry, but then that should give us good hypotheses to go back to. Behavioral studies are captive in the wild and see if what we're seeing in the anatomy matches the behaviors and how to put all of that pieces together. So this is really work that's in its infancy in terms of what we can do, but I think it has tremendous potential. It's going to reveal so much. I hope so. I think about my mum who's a quilter, and she does these amazing stitches and then I liken it to a chimp picking and you know, there's a lot of very fine motor activities that I think will be illuminated by.
This, and I hope so. And in primate evolution, the idea is if you're in the tree, it's really important that you don't fall out of the tree. That's pretty obvious.
And so the the having a feet feet that can grasp and hold on tightly, that frees up the hands to be able to do all those kinds of things, open fruits, groom each other, all those other things that are even getting it. Maybe it's probably a little bit of a stretch, even look at aspects of social behavior and so forth. And primates evolution earlier on. The interplay between is in the hands of feet is something we also don't really have a very good idea of.
And we're hoping that this project will move us in that direction. Wonderful. Speaking of feet now, what did Australopithecus feet look like compared to Homo erectus and Homo Niran Neanderthal? Absolutely. Very, very similar. And the important was so the toes would have been in line with the rest of the digits.
There would have been an arch in the foot. We can actually see arches in the footprints and in the bones. So it would have been very similar. Australopithecus probably had a little bit longer toes than we do, which seems to be from the fossils. And some scholars have argued that the big toe is a little bit more divergent from the rest of the digits, but nothing like we see in any other primate that's pretty much ever lived that we know of.
And to me, the most compelling argument for how important being good walking on the ground is that we gave up have a grasping big foot, a big toe to move around in the trees. We can get in trees. Australopithecus almost certainly climbed in trees and they were probably better at than we are. They were stronger. They had a few other sort of minor differences that were able to be a little bit better. But if you're, for example, a female that's holding a baby that doesn't have grass and big toes to hold on to your fur and you only have one grasping appendage left, it's really hard to move well, efficiently, quickly in the trees, anything like a great ape does.
We gave that pup to take reach purpose all of those muscles and soft tissues on the bottom of the foot to be efficient and effective walking on the ground. So it must have been really important to do that well for selection, to give all of that up. And it does seem that maybe early hominids did go into trees now and then and they would have been better, like I say. But fundamentally, the thing that selection was acting on so strongly was walking well on the ground on two feet. And that's why I think it's so important. So to me, feet are the most telling aspect of all of the skeleton in terms of natural selection and what selection was favoring.
Yeah, and just so Homo erectus in the tunnels, there was a little bit of change, but it was really relatively minor after that point. Mate, before I go on to some of these questions, are there other signals in the fossil record, other forms of evidence that give you more information about the actual environment that these human evolutionary features evolved in? So other plants or animals that show this transition from forest to savanna, for example? Absolutely. In fact, when we're in the field, when we're finding fossils, and if you dip your toe into the scientific literature on human evolution, a lot of and most in some ways of what we're talking about is the other animals in the environments.
Hominids are maybe 1% of the animals out there that we find even of the large vertebrates that we can actually see in the fossil record. And there's a lot of interest, of course, in how humans are related to the environment. What about our evolution may have been driven by or influenced by environmental change and so forth, And there are a lot of papers that was one that just came out recently about some fossil apes and the importance of grasslands and adaptation and so forth. And it seems that with Australopithecus they lived in some variable environments. They're pretty flexible, but they weren't in deep forests.
They were in sort of semi-open woodlands, somewhat variable, some little wetter, some a little bit drier. But some of the big questions with variation among Australopithecus species and what may have happened later may have t
2023-05-15