Excerpts from http://www.anthropology.ccsu.edu/faculty/park/latebreaking.htm In a related story in the New York Times, October 20, 1998, p. F1, scientists at Genoplex, a Denver company exploring chimp genes for medical reasons, have stated that the number of genes differentiating chimps from humans may only be a few hundred, with just 50 accounting for our cognitive differences. They have already identified a gene that may contribute to chimps' greater resistance to AIDS. As in the above piece, they surmise that the genetic differences relate to small changes in gene that regulate fetal development. They claim, for example, that a genetic program that allows time for the brain cells of a fetus to go through one additional doubling would account for the resultant greater size of the adult human brain. Similarly, our flat faces could result from a program that arrested the forward movement of the face of fetal chimps. Other differences could lie in the flipped portions of chimp chromosomes as compared to humans, leading certain genes to be in different environments and be more or less active or acquire new roles. An area of research that would further this study would be the sequencing of genomes of a larger series of primates. Chapter 10: A brief article in the November 8, 1998 Discover, p. 32 reports some computer simulations done with the reconstructed skeleton of Lucy (A. afarensis) at the University of Liverpool. The program modeled the biomechanics of both an erect and a bent-hip/bent-knee ("Groucho") gait. The study concluded that the Groucho gait was not only energy inefficient but also would have raised body temperature as much as 12 degrees (they didn't say on what scale). Lucy, according to this study, walked fully erect. On the same page is another brief piece about some research indicating that human's large gluteus maximus muscles are a product of our bipedal locomotion. Apes have smaller "butts" (as the article puts it) with the gluteus maximus attached to the ischium. Such a muscle and attachment can't keep apes in an erect posture for long. The human muscle is larger and attached higher up, on the ilium. ---------------------------------------------------------------- http://www.pbs.org/saf/1103/resources/transcript.htm Transcript, Scientific American Frontiers, show 1103 "Life's Really Big Questions" Ð SHOW 1103 Episode Open Noah's Snowball Handmade Humans Robot Independence Alien Worlds I, Robot ... HANDMADE HUMANS ALAN ALDA Billions of years of evolution has produced probably billions of different living things. But of those billions, only one -- so far as we know -- wonders about how and even why it's here. Which poses perhaps the biggest of life's big questions. What happened some four or five million years ago that set us off on our unique journey to becoming Homo sapiens? We know it happened in Africa, when a species of ape left the trees of the forest behind and strode away on two legs, freeing its hands to becomeÉ well, that's what our next story is going to explore. RESEARCHER Make a fist. Point at something. ALAN ALDA (Narration) I'm returning to the stone age -- equipped with a cyberglove, able to measure every subtle movement of my fingers and hand. It's a great mix: the very latest in high tech being used to study the oldest tech of all -- tools made of stone. RESEARCHER Close your fist. ALAN ALDA Ah, there, I got a nice piece there. STEVE SHAKELY I think we have natural here. ALAN ALDA Now I have two. Here, you want to cut some? I'll go halves with you on that antelope. Well, how did I do with this? Mary Marzke I think we're quite impressed with how you did with that. Very effective. Removed a lot of flakes. ALAN ALDA So that must mean it must be innate, right? ALAN ALDA (Narration) That's the idea we're exploring in this story -- that our hands were designed for making stone tools -- that they were in fact designed by making stone tools. STEVEN SHAKLEY You've got quite a cutting edge here, so you'd be quite competitive. So you can move up 100,000 years. ALAN ALDA (Narration) Of course, the hands of our ancestors got a great start. This is Tujo the orang-utan, one of the stars of the Phoenix Zoo. Orangs and humans last shared a common ancestor about 12 million years ago. While we've both been evolving ever since, Tujo's hands give us a glimpse of what ours may have once been -- extremely dexterous, but shaped by a life in the trees. MARY MARZKE You notice that he's carrying it in his foot. ALAN ALDA Yeah. MARY MARZKE When they're moving around, they have two hands that they're moving on the branches with. And the only way to keep the fruit with them is to carry it in the foot. And the feet act very much in coordination with the hands in manipulating foods. ALAN ALDA (Narration) Tujo uses his feet not just to carry the grapefruit but to help eat it too -- and needs at least both of his hands to help resist the pull of his teeth. MARY MARZKE Possibly we would do that with a big piece of fruit, but as it gets smaller we would get a good purchase on it with our thumb and fingers which adapt to the shape of the grapefruit. ALAN ALDA (Narration) To Mary Marzke this is an important clue as to what makes our hands different -- and far more capable. But before our hands could change they had to be free. And that meant standing on our own two feet. ALAN ALDA Is that Lucy there? WILLIAM KIMBEL This is Lucy. This actually is a copy of her bones. ALAN ALDA (Narration) Our most famous ancestor, Lucy lived about 3.2 million years ago in what is now Ethiopia. ALAN ALDA How do you know she was an adult? WILLIAM KIMBEL Well, we have her lower jaw. And we can see that her last molar tooth, the so-called wisdom tooth, is erupted and was being used for chewing. (And we can actually see that) because the tips of the little cusps on top of the teeth are polished and worn, (meaning that she was using them to chew.) That's full adulthood. Three and a half feet tall, however, which is you know, when down on the ground is not much bigger that a good sized umbrella you know when you put its tip on the ground. So she's very tiny. Her brain -- although we don't have too much of her skull, unfortunately -- what we do have suggests a brain size not much bigger than that of a chimpanzee. And that really drives home one of the most important points about Lucy. And that is the stark contrast between her anatomy beneath the neck, which is fully consistent with an upright two-legged walking; and the anatomy above the neck with a very primitive ape-like jaw and teeth and a very tiny brain. ALAN ALDA (Narration) One of the below-the-neck features suggesting Lucy walked upright is her pelvis -- short and wide when compared to the pelvis of a chimp. Then there are the leg-bones themselves. WILLIAM KIMBEL You can see here's the hip and here's the knee. And there's a very pronounced angle as the thighbone runs from the hip joint to the knee. With the knees being much closer together. ALAN ALDA Yeah, I can see that over here too. WILLIAM KIMBEL Very obvious. Very obvious in a human. And in a chimpanzee, when it stands upright, that's not the case. The thighbone is more or less perpendicular to the ground, in contrast to what we see in Lucy and modern humans. ALAN ALDA (Narration) This combination of a tall pelvis and upright thighs give chimps their characteristic waddle when they walk on two legs -- not an efficient way of getting around -- especially when you're in a hurry. But Lucy was probably quick on two legs, and she had bipedalism's most useful spin-off -- genuine hands rather than modified feet. ALAN ALDA Is this Lucy's hand or one of her relatives? MARY MARZKE This is a composite set of hand bones from Lucy's relatives. Beautifully preserved. Very nice joint surfaces. And some of the interesting things are at the base of the index finger where there are three joint surfaces, and these surfaces are oriented in the way that they are in modern humans. And they are all different from the way that they are oriented in chimpanzees. And the different orientation would have allowed a little bit of rotation of the index fingerÉ ALAN ALDA Rotation meaning what? MARY MARZKE Rotation toward the thumb. And when you rotate the index finger toward the thumb, this helps you to grasp. ALAN ALDA (Narration) Lucy's ability to pick up and firmly grasp an object like a round stone opened up a whole new way of earning a living. Chimpanzees throw stones -- but underhand and not very accurately. Lucy's ability to hurl a rock hard and on target brought her into a different league. ALAN ALDA Would Lucy have been able to pitch? MARY MARZKE She could have. She had the anatomy to do it. And if she had practiced she would have been able to pitch. She had a hand that could have grasped the ball, and controlled it. And she had a pelvis that allowed the balance of the trunk on the hind limbs. So she could have used her trunk as leverage in pitching. As we watch these pitchers, they're rotating their trunk and then they're putting on the brake with their gluteus maximus muscle so that their arm accelerates in a whip-like way. And she had both of these features both in the hip region and in the hand. So it takes a lot of practice, but she could have done it. ALAN ALDA (Narration) Of course, Lucy's strikes weren't on batters but small game -- and could have significantly increased her food supply. We're back in the lab again, where Mary has assembled a team of experts to delve more deeply into the link between anatomy and the technological breakthroughs that set our ancestors apart from everything that had lived before. RONALD LINSCHEID Ouch! ALAN ALDA (Narration) Dr Ronald Linscheid is a retired hand surgeon. Nick Toth is an archeologist. The needles in Nick's arm and hand are implanting thin wire electrodes into his muscles to measure how vigorously they contract. RONALD LINSCHEID You're going to feel a little stick right about there. May have felt that hit the bone a little bit. ALAN ALDA (Narration) Nick will also be wearing the cyberglove I was modeling earlier -- and you'll understand now why my participation in the experiment ended right there. MARY MARZKE Alright Nick, imagine there's an animal there, and that's your food for the night. ALAN ALDA (Narration) Mary's purpose in organizing this little party is to closely monitor the hand and its muscles when Nick, then his wife, Kathy Schick, start behaving like stone-agers. Our ancestors from the time of Lucy -- 3.2 million years ago -- may have been hot on the moundÉ But they would have had problems at the plate. Here's a chimpanzee letting off steam with a stick. He's swinging it with great determination, but his grip is quite different from that used by a baseball batter. Our old friend Tujo the orang-utan uses the same grasp as the chimp, with all four fingers curled into his palm. Neither modern orangs nor chimps -- or even, it turns out, Lucy -- can do what we can do: rotate our little finger across the palm to touch the thumb. MARY MARZKE The advantage of having this rotation can be seen when you hold something cylindrical, like this bone, where you grasp things in a trough, across the palm with the little finger and the thumb strongly opposed. And this allows you to bring the tool down in line with your arm. ALAN ALDA That's interesting. I was taught in tennis to squeeze these last two fingers as I hit the ball. And that gives control. MARY MARZKE Yes. ALAN ALDA And that's what they were able to do when they shifted over to this kind of a finger. MARY MARZKE Yes. ALAN ALDA (Narration) It was a shift that didn't take place for a few hundred thousand years after Lucy's time -- but when it did, our ancestors would certainly have made the most of it. After stunning, say an antelope with a well-aimed stone, the tennis racquet grip would have made finishing it off much easier. Of course, not everything was easy to kill. ALAN ALDA So what did it take, about a million years for people to find out you couldn't kill a pillow? ALAN ALDA (Narration) But look at this. As Steve Shakely takes his turn with the glove and the electrodes while making a stone tool, you can see he's relying on the flexibility of his hand to manipulate and grip the stone he's hitting. ALAN ALDA There's so much attention paid to the opposable thumb. But the opposable pinky turns out to be really valuable. I mean, if I hit this stone without that little finger giving me pressure, this stone would just come right out of my hand, right? MARY MARZKE Yes. ALAN ALDA I can really manipulate it and keep it right where I need it with strength. ALAN ALDA (Narration) So while Lucy could have gripped the hammer stone like a baseball, only her descendents could have cradled the stone being struck firmly enough to have fashioned it into something useful. Mary Marzke plans to use the data she's getting from her volunteer Stone-agers to help her interpret the fossil bones that are all that remain of our ancestors. Kathy Schick meanwhile has re-discovered the one inescapable consequence of making stone tools. ALAN ALDA So what have you left yourself with here? KATHY SCHICK Tourniquet! You don't want to see this. ALAN ALDA Oh God! You know this is heroic what you're doing for science. In all the years we've been doing this show I've never seen people bleed for science like that. KATHY SCHICK Only a flesh wound! ALAN ALDA (Narration) From the time our still non-human ancestors started making stone tools two and a half million years ago, until just a few thousand years ago, this is how we fashioned the tools and weapons we used gradually to dominate our planet. With grips we use today to hold a bat and ball, our hands helped make us human. ALAN ALDA I get the impression talking to both of you that we can do amazing things with our hands now because of what these people did a couple of million years ago with stones. We can work the keys of a computer. But I also get the impression that the very invention of a computer, the way we use our minds to come up with a computer, is in a way an outgrowth of this stone work. STEVE SHAKELY Very much so. ALAN ALDA Trace that for me a little bit. You may not be able to document every step along the way, but what's your thinking on that? STEVE SHAKELY Well, I think a lot of it has to do with, we as human's ability -- and I think that really separates us much from the animal world -- this ability to look into the future. To build something today that will make our lives easier tomorrow. Now some might argue that computers don't necessarily do that, they make our lives more complicated. But I think that in general that's why computers were invented, to make our lives easier in the future, to get through the day. And stone tools were no different. And somebody 2.5 million years ago must have discovered and thought and invented this piece, this flake, to make his or her life easier in the future.