Posted on 11/17/2004 7:54:27 PM PST by neverdem
Eadweard Muybridge/Bettmann Corbis
Edward Muybridge's 1887 motion study of an athlete running.
The evolution of a physique for long-distance running is what made humans look the way we do now - whether winning a marathon, nursing a strained Achilles' tendon or sitting on an ample gluteus maximus in front of the TV.
The apparently crucial role of running in human evolution, overlooked for the most part in previous research, is being proposed today in an article in the journal Nature by two American scientists.
While walking upright first set early human ancestors apart from their ape cousins, the scientists write, it may have been the ability to run long distances with springy step over the African savanna that influenced the transition to today's human body form.
Endurance running, unique to humans among primates and uncommon in all mammals other than dogs, horses and hyenas, apparently evolved at least two million years ago and probably enabled human ancestors to hunt and scavenge for food over large distances. And that, in turn, probably proved decisive in their pursuit of high-protein food for development of larger brains.
The scientists, Dr. Dennis M. Bramble of the University of Utah and Dr. Daniel E. Lieberman of Harvard, reported that their analysis of the fossil record showed striking anatomical evidence for the capability of prolonged running in the Homo genus as early as two million years ago.
'Today, endurance running is primarily a form of exercise and recreation, but its roots may be as ancient as the origin of the human genus," the scientists concluded in the article.
Dr. Bramble, a professor of biology and a specialist in the biomechanics of animal locomotion, said, "Running made us human, at least in an anatomical sense," adding that he and Dr. Lieberman were "very confident that strong selection for running was instrumental in the origin of the modern human body form."
Other paleontologists not involved in the research praised the hypothesis as an important insight into the apparent significance of long-distance running in human survival and evolution. But they raised questions over what stimulated the physical transition that led to this human capability.
By two million years ago, Dr. Bramble and Dr. Lieberman noted, early species of the Homo family, beginning at least with Homo erectus, had long, slender legs for greater strides. They had shorter arms and a narrower ribcage and pelvis. Their skulls included features to help prevent overheating. A ligament attached to the base of the skull kept their heads steady as they ran.
Although tissues do not fossilize, traces of muscle and tendon attachment points on bones of early species revealed an extensive network of springy tendons along the back of their legs and feet, including a well-developed Achilles' tendon that anchors the calf muscles to the heel bone. Tendons served to store and release elastic energy during running, but were not needed for ordinary walking.
And there was the gluteus maximus, the muscle of the buttocks. Earlier human ancestors, like chimpanzees today, had pelvises that could support only a modest gluteus maximus, nothing like the strong buttocks of Homo.
"Have you ever looked at an ape?" Dr. Bramble said. "They have no buns."
Dr. Lieberman, a paleontologist, explained: "Your gluteus maximus stabilizes your trunk as you lean forward in a run. A run is like a controlled fall, and the buttocks help to control it."
The two scientists speculated in the article and in interviews that running by early human ancestors was more than simply a natural step, so to speak, beyond upright walking. These apelike ancestors, the scientists noted, were walking almost three million years before they became runners and began to assume more modern physiques.
In such ancestors as the Australopithecus genus, famous for the 3.2 million-year-old Lucy skeleton, the physical characteristics favoring running were either absent or underdeveloped.
Somehow, the scientists continued, those early ancestors who developed primitive running attributes must have improved their chances of survival and reproduction. They were not as swift in a sprint as their contemporary four-legged competitors for prey. But their ability to run greater distances than other predators must have been an advantage in making a kill or at least scavenging the kills of their swifter rivals.
But running came to early Homo at a cost: the loss of physical traits useful for climbing trees for refuge and food. By this time, other scientists have noted, climate change had diminished the woodlands of East Africa, leaving more open grasslands to run long distances over.
Dr. Philip Rightmire, a paleoanthropologist at the University of Binghamton in New York, said the Bramble-Lieberman hypothesis was "a pretty compelling picture of the importance of running in human evolution, and, over all, I'm very impressed."
Endurance running and the evolution of Homo
DENNIS M. BRAMBLE1 AND DANIEL E. LIEBERMAN2
1 Department of Biology, University of Utah, Salt Lake City, Utah 84112, USA
2 Peabody Museum, Harvard University, Cambridge, Massachusetts 02138, USA
Correspondence and requests for materials should be addressed to D.M.B. (bramble@bioscience.utah.edu) or D.E.L. (danlieb@fas.harvard.edu).
Striding bipedalism is a key derived behaviour of hominids that possibly originated soon after the divergence of the chimpanzee and human lineages. Although bipedal gaits include walking and running, running is generally considered to have played no major role in human evolution because humans, like apes, are poor sprinters compared to most quadrupeds. Here we assess how well humans perform at sustained long-distance running, and review the physiological and anatomical bases of endurance running capabilities in humans and other mammals. Judged by several criteria, humans perform remarkably well at endurance running, thanks to a diverse array of features, many of which leave traces in the skeleton. The fossil evidence of these features suggests that endurance running is a derived capability of the genus Homo, originating about 2 million years ago, and may have been instrumental in the evolution of the human body form.
To be sure that's not Michael Moore above, sorry folks, somebody had to say it.
Ahhh...yes, but the only guilty "ancestors" responsible for this global climate shift were the ones located on the land of present day United States of America!
Ha,-ha!
November 18, 2004
Running Extra Mile Sets Humans Apart in Primates' World
By JOHN NOBLE WILFORD
If walking upright first set early human ancestors apart from their ape cousins, it may have been their eventual ability to run long distances with a springing step over the African savanna that influenced the transition to today's human body form, two researchers are reporting today.
The evolution of physiques for distance running made humans look the way we do now, whether winning a marathon, nursing a strained Achilles tendon or sitting on an ample gluteus maximus in front of the TV.
Endurance running, unique to humans among primates and uncommon in all mammals other than dogs, horses and hyenas, apparently evolved at least two million years ago and probably let human ancestors hunt and scavenge over great distances. That was probably decisive in the pursuit of high-protein food for development of large brains.
The apparently crucial role of running in human evolution has been largely overlooked in previous research. But today, the two scientists, Dr. Dennis M. Bramble of the University of Utah and Dr. Daniel E. Lieberman of Harvard, report in the journal Nature that their analysis of the fossil record found striking anatomical evidence for the capability of prolonged running in the Homo genus, beginning about two million years ago.
"Today, endurance running is primarily a form of exercise and recreation, but its roots may be as ancient as the origin of the human genus," the scientists conclude in the article.
Dr. Bramble, a professor of biology and a specialist in the biomechanics of animal locomotion, said, "Running made us human, at least in an anatomical sense," adding that he and Dr. Lieberman were "very confident that strong selection for running was instrumental in the origin of the modern human body form."
Paleontologists not involved in the research praised the hypothesis as an important insight into the apparent significance of long-distance running in human survival and evolution. But they raised questions about what stimulated the physical transition that led to this human capability.
By two million years ago, Dr. Bramble and Dr. Lieberman noted, early species of the Homo family, notably Homo erectus, had long, slender legs for greater strides. They had shorter arms and a narrower rib cage and pelvis. Their skulls included features to help prevent overheating. A ligament attached to the base of the skull kept their heads steady as they ran.
Although tissues do not fossilize, traces of muscle and tendon attachment points on bones of early species revealed an extensive network of springy tendons along the back of the legs and feet, including a well-developed Achilles tendon that anchored calf muscles to the heel bone. Tendons served to store and release elastic energy during running but were not needed for ordinary walking.
And there was the gluteus maximus, the muscle of the buttocks. Earlier human ancestors, like chimpanzees today, had pelvises that could support only a modest gluteus maximus, nothing like the strong buttocks of Homo.
"Have you ever looked at an ape?" Dr. Bramble said. "They have no buns."
Dr. Lieberman, a paleontologist, explained: "Your gluteus maximus stabilizes your trunk as you lean forward in a run. A run is like a controlled fall, and the buttocks help to control it."
The scientists compiled a list of 26 traits connected with running that early Homo specimens exhibited. It was a result of 13 years of research that started with watching pigs running on a treadmill.
"Dennis and I noticed how the pigs can't hold their heads still while running," Dr. Lieberman recalled. "Any good human runner keeps his head still because of the nuchal ligament, a tendon in the back of the neck."
The scientists learned that all accomplished running animals, modern or fossil, had a mark in the skull where the nuchal ligament had been. They found it in early Homo specimens, but not in Australopithecus, the genus that lived more than three million years ago and included the 3.2-million-year-old Lucy skeleton.
"That was an epiphany for us," Dr. Lieberman said.
Dr. Philip Rightmire, a paleoanthropologist at Binghamton University in New York, said the Bramble-Lieberman hypothesis was "a pretty compelling picture of the importance of running in human evolution, and overall, I'm very impressed."
Dr. Rightmire, who did not participate in the research, said the hypothesis made sense if the evolutionary focus was limited to Africa, particularly the increasingly open grasslands, where ancestral Homo specimens were more likely to have tall, lithe bodies. But "the picture is less clear," he said, among the early Homo erectus migrants out of Africa, many of whom appear to have been small and stocky.
The two scientists speculated in the article and in interviews that running by early human ancestors was more than simply a natural step, so to speak, beyond upright walking. These apelike ancestors, the scientists noted, were walking almost three million years before they became runners and began to assume more modern physiques.
In such ancestors as Australopithecus, the physical characteristics favoring running were either absent or underdeveloped. They had short legs, long forearms and high, permanently shrugged shoulders. The fossil record is scant in the million-year transitional period between most australopithecines and the emergence of Homo erectus.
Somehow, the scientists continued, those early ancestors who developed primitive running attributes must have improved their chances of survival and reproduction. They were not as swift in a sprint for prey as their contemporary four-legged competitors. But their ability to run greater distances than other predators must have been an advantage in making a kill or at least scavenging the kills of their swifter rivals.
In the journal article, the scientists suggested that endurance running "may have made possible a diet rich in fats and proteins thought to account for the unique human combination of large bodies, small guts, big brains and small teeth."
But the scientists conceded that it might be difficult to establish to what extent the running capability proved useful in hunting and scavenging.
Dr. Alan Walker, a paleoanthropologist at Penn State University who has excavated Homo erectus specimens in Africa, said the new research on long-distance running had yet to explain the stimulus for the transition in anatomy and the specific importance of the change to early human survival - whether it might have been for hunting, scavenging or escaping predators.
About one consequence of the evolved running physique there is little doubt. Running came to early Homo at a cost: the loss of physical traits useful for climbing trees for refuge and food. By this time, however, the climate and the landscape were changing, scientists have learned, and the woodlands of East Africa were giving way to arid grasslands and miles of running room.
Running Extra Mile Sets Humans Apart in Primates' World
FReepmail me if you want on or off my health and science ping list.
Are you ready to run 100 miles?
American Ultrarunning Association (AUA)
http://www.americanultra.org/
Or seven DAYS?
"When the body has given up the ghost, only through will power can it be mobilised. It is not easy to grasp what is taking place in the mind and the soul, in the senses and beyond the senses of a runner due to the refusal of the body. Only if the runner achieves his transcendence, and especially at a metaphysical level, is he then be able to continue."
Extract from Yianni's book, The Six-Day Run of the Century
http://www.yianniskouros.com/html/Road_Records.htm
Thanks for the links.
Also the structure of our arms is great for balancing our strides when running and thus more cost effective in energy.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.