Big break in evolution...

[R13]

More and more evidence...


(CNN) -- The oldest-known hominid skeleton was a 4-foot-tall female who walked upright more than 4 million years ago and offers new clues to how humans may have evolved, scientists say.

This sketch shows what a 4 million-year-old hominid, nicknamed Ardi, may have looked like.

Scientists believe that the fossilized remains, which were discovered in 1994 in Ethiopia and studied for years by an international team of researchers, support beliefs that humans and chimpanzees evolved separately from a common ancestor.

"This is not an ordinary fossil. It's not a chimp. It's not a human. It shows us what we used to be," said project co-director Tim White, a paleontologist at the University of California, Berkeley.

Ardipithecus ramidus, nicknamed "Ardi," is a hominid species that lived 4.4 million years ago in what is now Aramis, Ethiopia. That makes Ardi more than a million years older than the celebrated Lucy, the partial ape-human skeleton found in Africa in 1974.

Ardi's 125-piece skeleton includes the skull, teeth, pelvis, hands and feet bones. Scientists say the data collected from Ardi's bone fragments over the past 17 years push back the story of human evolution further than previously believed.

"In fact, what Ardipithecus tells us is that we as humans have been evolving to what we are today for at least 6 million years," C. Owen Lovejoy, an evolutionary biologist at Kent State University and project anatomist, said Thursday.
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Analysis of Ardi's skeleton reveals that she weighed about 110 pounds, had very long arms and fingers, and possessed an opposable big toe that would have helped her grasp branches while moving through trees.

Ardi's brain was believed to be the size of a chimp's, but she also had many human-like features, such as the ability to walk upright on two legs. Her "all-purpose type" teeth indicate that she probably ate a combination of plants, fruits and small mammals, scientists say.

"The anatomy behind this behavioral combination is very unexpected and is certain to cause considerable rethinking of not only our evolutionary past, but also that of our living relatives: the great apes," said Alan Walker, professor of biological anthropology at Pennsylvania State University.

Many scientists hypothesize that humans took a different evolutionary trajectory from those of chimpanzees, bonobos and gorillas. Ardi's findings help challenge earlier beliefs that humans evolved from chimpanzees, their closest genetic relatives, scientists say.

Researchers are still trying to pinpoint when the two lineages -- chimps and humans -- split from their common ancestor.

Digging up the past has not been easy.

Scientists stumbled upon the Ardipithecus fossil in 1994 when a graduate student found a single upper molar tooth. The rest of Ardi's fossilized bones, sandwiched between layers of volcanic rock, took three years to be recovered and many more to be analyzed.

"In many ways, the discovery of Ardipithecus has been like a marathon," White said.

"Ardipithecus ramidus and its prevailing anatomy revolutionize the way most of us understood the earlier part of our evolutionary history," said team member Yohannes Haile-Selassie, paleontologist at the Cleveland Museum of Natural History.

The Ardi findings are the work of 47 paleontologists and geologists representing 10 countries. The results will be published Friday in 11 articles in a special edition of the journal Science.

Until now, Australopithecus, nicknamed "Lucy," was the oldest fossil studied by scientists seeking to explain human evolution. Lucy is believed to have lived about 3.2 million years ago in what is now Ethiopia.

Many scientists credit Ethiopia with taking the lead in helping the world better understand the origins of humans.

"This finding points to a deeper sense of our [humans'] interconnectedness," Samuel Assefa, Ethiopian ambassador to the United States, said Thursday. "We are all Ethiopians at heart."

Ardi's skeleton resides in the National Museum of Ethiopia in Addis Ababa.



Oldest human skeleton offers new clues to evolution - CNN.com

[Gotch]

If memory serves, this is the one that was pieced together from bits found spread over a huge radius, something like a full mile, with the toe bone that is so crucial to the conclusion being found even further away (I've heard 10 miles). Donald Johanson among (many) others does not believe the toe bone actually goes with the rest of the pieces and without it there can not even be a presumption of upright posture and the entire hominid theory rests solely on that.

Again, I can not fully express just how thoroughly underwhelmed I am.

[Biggin]

This is a big deal.

Its not quite the 'missing link,'but a discovery like this is a major event.

The leg bones, pelvis, etc. all show that the discovery walked upright. The toe was only a small part in that. There is no doubt all the fossils came from the same person.
47 authors, from 10 different countries. That'd have to be a helluva coverup.

"The structure of Ardi's upper pelvis, leg bones and feet indicates she walked upright on the ground, while still retaining the ability to climb. Her foot had an opposable big toe for grasping tree limbs but lacked the flexibility that apes use to grab and scale tree trunks and vines ("Gorilla and chimp feet are almost like hands," says Lovejoy), nor did it have the arch that allowed Australopithecus and Homo to walk without lurching side to side."

Ardi Fossil Discovery: New Human-Evolution Puzzle Piece - TIME

[Shooter]

How does this prove evolution at all? All it sounds like to me, is a discovery of a different species that went EXTINCT. I mean when you read the post you put up...it sounds a whole lot more like some type of ape then a human anyway. Just because its 4 illion years old doesnt mean it was the beginning of a human.

[R13]

How does this prove evolution at all? All it sounds like to me, is a discovery of a different species that went EXTINCT. I mean when you read the post you put up...it sounds a whole lot more like some type of ape then a human anyway. Just because its 4 illion years old doesnt mean it was the beginning of a human.

This is one of the major points of evolution, that around this time, the lineages diverged and the hominid(which is what this is) was the result. This is a huge deal like Biggin said, HUGE discovery. It does actually mean this was the beginning of the human.

[Gotch]

No it doesn't.

You've got like 5% of the total skeletal structure, a doctrine to feed and support and whole big ol' bunch of hopeful evolutionists ready to exaggerate.

In all honesty a careful read of the "Time" story is hilarious.

[R13]

You do know that even one piece found from this is by luck? This is a four and a half MILLION year old skeleton, most of the ones found now could turn to dust if really touched. This find is once in a life time, extremely rare and a huge find, big win for evolutionists. Here's a national geographic story I read earlier that explains it better....


Move over, Lucy. And kiss the missing link goodbye.

Scientists today announced the discovery of the oldest fossil skeleton of a human ancestor. The find reveals that our forebears underwent a previously unknown stage of evolution more than a million years before Lucy, the iconic early human ancestor specimen that walked the Earth 3.2 million years ago.


The centerpiece of a treasure trove of new fossils, the skeleton—assigned to a species called Ardipithecus ramidus—belonged to a small-brained, 110-pound (50-kilogram) female nicknamed "Ardi." (See pictures of Ardipithecus ramidus.)

The fossil puts to rest the notion, popular since Darwin's time, that a chimpanzee-like missing link—resembling something between humans and today's apes—would eventually be found at the root of the human family tree. Indeed, the new evidence suggests that the study of chimpanzee anatomy and behavior—long used to infer the nature of the earliest human ancestors—is largely irrelevant to understanding our beginnings.

Ardi instead shows an unexpected mix of advanced characteristics and of primitive traits seen in much older apes that were unlike chimps or gorillas (interactive: Ardi's key features). As such, the skeleton offers a window on what the last common ancestor of humans and living apes might have been like.

Announced at joint press conferences in Washington, D.C., and Addis Ababa, Ethiopia, the analysis of the Ardipithecus ramidus bones will be published in a collection of papers tomorrow in a special edition of the journal Science, along with an avalanche of supporting materials published online.

"This find is far more important than Lucy," said Alan Walker, a paleontologist from Pennsylvania State University who was not part of the research. "It shows that the last common ancestor with chimps didn't look like a chimp, or a human, or some funny thing in between." (Related: "Oldest Homo Sapiens Fossils Found, Experts Say" [June 11, 2003].)

Ardi Surrounded by Family

The Ardipithecus ramidus fossils were discovered in Ethiopia's harsh Afar desert at a site called Aramis in the Middle Awash region, just 46 miles (74 kilometers) from where Lucy's species, Australopithecus afarensis, was found in 1974. Radiometric dating of two layers of volcanic ash that tightly sandwiched the fossil deposits revealed that Ardi lived 4.4 million years ago.

Older hominid fossils have been uncovered, including a skull from Chad at least six million years old and some more fragmentary, slightly younger remains from Kenya and nearby in the Middle Awash.

While important, however, none of those earlier fossils are nearly as revealing as the newly announced remains, which in addition to Ardi's partial skeleton include bones representing at least 36 other individuals.

"All of a sudden you've got fingers and toes and arms and legs and heads and teeth," said Tim White of the University of California, Berkeley, who co-directed the work with Berhane Asfaw, a paleoanthropologist and former director of the National Museum of Ethiopia, and Giday WoldeGabriel, a geologist at Los Alamos National Laboratory in New Mexico.

"That allows you to do something you can't do with isolated specimens," White said. "It allows you to do biology."

(Related: Rediscover the original Ardipithecus.)

Ardi's Weird Way of Moving

The biggest surprise about Ardipithecus's biology is its bizarre means of moving about.

All previously known hominids—members of our ancestral lineage—walked upright on two legs, like us. But Ardi's feet, pelvis, legs, and hands suggest she was a biped on the ground but a quadruped when moving about in the trees.

Her big toe, for instance, splays out from her foot like an ape's, the better to grasp tree limbs. Unlike a chimpanzee foot, however, Ardipithecus's contains a special small bone inside a tendon, passed down from more primitive ancestors, that keeps the divergent toe more rigid. Combined with modifications to the other toes, the bone would have helped Ardi walk bipedally on the ground, though less efficiently than later hominids like Lucy. The bone was lost in the lineages of chimps and gorillas.

According to the researchers, the pelvis shows a similar mosaic of traits. The large flaring bones of the upper pelvis were positioned so that Ardi could walk on two legs without lurching from side to side like a chimp. But the lower pelvis was built like an ape's, to accommodate huge hind limb muscles used in climbing.

Even in the trees, Ardi was nothing like a modern ape, the researchers say.

Modern chimps and gorillas have evolved limb anatomy specialized to climbing vertically up tree trunks, hanging and swinging from branches, and knuckle-walking on the ground.

While these behaviors require very rigid wrist bones, for instance, the wrists and finger joints of Ardipithecus were highly flexible. As a result Ardi would have walked on her palms as she moved about in the trees—more like some primitive fossil apes than like chimps and gorillas.

"What Ardi tells us is there was this vast intermediate stage in our evolution that nobody knew about," said Owen Lovejoy, an anatomist at Kent State University in Ohio, who analyzed Ardi's bones below the neck. "It changes everything."

Against All Odds, Ardi Emerges

The first, fragmentary specimens of Ardipithecus were found at Aramis in 1992 and published in 1994. The skeleton announced today was discovered that same year and excavated with the bones of the other individuals over the next three field seasons. But it took 15 years before the research team could fully analyze and publish the skeleton, because the fossils were in such bad shape.

After Ardi died, her remains apparently were trampled down into mud by hippos and other passing herbivores. Millions of years later, erosion brought the badly crushed and distorted bones back to the surface.

They were so fragile they would turn to dust at a touch. To save the precious fragments, White and colleagues removed the fossils along with their surrounding rock. Then, in a lab in Addis, the researchers carefully tweaked out the bones from the rocky matrix using a needle under a microscope, proceeding "millimeter by submillimeter," as the team puts it in Science. This process alone took several years.

Pieces of the crushed skull were then CT-scanned and digitally fit back together by Gen Suwa, a paleoanthropologist at the University of Tokyo.

In the end, the research team recovered more than 125 pieces of the skeleton, including much of the feet and virtually all of the hands—an extreme rarity among hominid fossils of any age, let alone one so very ancient.

"Finding this skeleton was more than luck," said White. "It was against all odds."

Ardi's World

The team also found some 6,000 animal fossils and other specimens that offer a picture of the world Ardi inhabited: a moist woodland very different from the region's current, parched landscape. In addition to antelope and monkey species associated with forests, the deposits contained forest-dwelling birds and seeds from fig and palm trees.

Wear patterns and isotopes in the hominid teeth suggest a diet that included fruits, nuts, and other forest foods.

If White and his team are right that Ardi walked upright as well as climbed trees, the environmental evidence would seem to strike the death knell for the "savanna hypothesis"—a long-standing notion that our ancestors first stood up in response to their move onto an open grassland environment.

Sex for Food

Some researchers, however, are unconvinced that Ardipithecus was quite so versatile.

"This is a fascinating skeleton, but based on what they present, the evidence for bipedality is limited at best," said William Jungers, an anatomist at Stony Brook University in New York State.

"Divergent big toes are associated with grasping, and this has one of the most divergent big toes you can imagine," Jungers said. "Why would an animal fully adapted to support its weight on its forelimbs in the trees elect to walk bipedally on the ground?"

One provocative answer to that question—originally proposed by Lovejoy in the early 1980s and refined now in light of the Ardipithecus discoveries—attributes the origin of bipedality to another trademark of humankind: monogamous sex.

Virtually all apes and monkeys, especially males, have long upper canine teeth—formidable weapons in fights for mating opportunities.

But Ardipithecus appears to have already embarked on a uniquely human evolutionary path, with canines reduced in size and dramatically "feminized" to a stubby, diamond shape, according to the researchers. Males and female specimens are also close to each other in body size.

Lovejoy sees these changes as part of an epochal shift in social behavior: Instead of fighting for access to females, a male Ardipithecus would supply a "targeted female" and her offspring with gathered foods and gain her sexual loyalty in return.

To keep up his end of the deal, a male needed to have his hands free to carry home the food. Bipedalism may have been a poor way for Ardipithecus to get around, but through its contribution to the "sex for food" contract, it would have been an excellent way to bear more offspring. And in evolution, of course, more offspring is the name of the game (more: "Did Early Humans Start Walking for Sex?").

Two hundred thousand years after Ardipithecus, another species called Australopithecus anamensis appeared in the region. By most accounts, that species soon evolved into Australopithecus afarensis, with a slightly larger brain and a full commitment to a bipedal way of life. Then came early Homo, with its even bigger brain and budding tool use.

Did primitive Ardipithecus undergo some accelerated change in the 200,000 years between it and Australopithecus—and emerge as the ancestor of all later hominids? Or was Ardipithecus a relict species, carrying its quaint mosaic of primitive and advanced traits with it into extinction?

Study co-leader White sees nothing about the skeleton "that would exclude it from ancestral status." But he said more fossils would be needed to fully resolve the issue.

Stony Brook's Jungers added, "These finds are incredibly important, and given the state of preservation of the bones, what they did was nothing short of heroic.

But this is just the beginning of the story."

Oldest "Human" Skeleton Found--Disproves "Missing Link"

[Biggin]

How can you say that with a straight face?

This was a previously undiscovered species.

This 'no big deal' discovery is of an ancient mammal that walked upright like a human.

The discovery could very well be the missing link, the piece of the evolution puzzle that both chimps and man evolved from.
The upright walking, the basic human structure, with long fingers and arms, and an opposable toe.

I just don't see how anyone can just laugh this off. To do that, is to mightily underestimate its importance. This is a major scientific discovery. This does not prove evolution, not even close. But this is a major piece in the evolution time line. This is not a definitive answer, or proof of concept, but this is a major piece of evidence to support the theory.
This is not the proof of evolution, this is a a big piece of evidence that supports the theory.

And Time is not a reputable source? Since when? There was nothing funny in the TIME story, it was a great recap of a very big scientific discovery.

[sup-rbeast]

IDK why we keep arguing over creation vs. evolution. We'll never know for sure how we got here..and you'll never change a person's belief in either.

[R13]

That's all things like this is, beating a dead horse, but if we just accepted that...we'd have nothing to talk about.