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Move over, Lucy, and kiss the missing link goodbye” EBQ

Oldest Skeleton of Human Ancestor Found

Jamie Shreeve
Science editor, National Geographic magazine

October 1, 2009 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.

But this is just the beginning of the story."

What Was "Lucy"? Fast Facts on an Early Human Ancestor

National Geographic News
September 20, 2006
Perhaps the world's most famous early human ancestor, the 3.2-million-year-old ape "Lucy" was the first Australopithecus afarensis skeleton ever found, though her remains are only about 40 percent complete (photo of Lucy's bones).
Discovered in 1974 by paleontologist Donald C. Johanson in Hadar, Ethiopia, A. afarensis was for about 20 years the earliest known human ancestor species (Africa map).
What did Lucy look like?
With a mixture of ape and human features—including long dangling arms but pelvic, spine, foot, and leg bones suited to walking upright—slender Lucy stood three and a half feet (107 centimeters) tall.
Recreations based on other A. afarensis skulls later found nearby reveal an apelike head with a low and heavy forehead, widely curving cheekbones, and a jutting jaw—as well as a brain about the size of a chimpanzee's.
Why was Lucy named Lucy?
Inspired by repeated playings of "Lucy in the Sky With Diamonds" at a celebratory party on the day the specimen was found, researchers gave it the Beatles' mod moniker.
How do we know Lucy was female?
Lucy's size gives her away as a female. Later fossil discoveries established that A. afarensis males were quite a bit larger than females.
Was Lucy an adult?
A number of factors point to Lucy being fully-grown. For one thing, her wisdom teeth, which were very humanlike, were exposed and appear to have been in use for a while before her death. In addition, the sections of her skull—separated in children—had grown together.

Questions: answer in complete sentences and support your answers with evidence ….

1.  How old is Lucy’s skeleton? How did scientists determine her age?

2.  Who was the first person to discovery Lucy and where was Lucy discovered?

3.  What is the big controversy about Lucy?

4.  Was Lucy male or female? How did scientists figure this out? Why did they name her Lucy?

5.  Describe Lucy’s physical profile and how she is similar and different to a human? (feel free to sketch a profile)

6.  What is your opinion about the missing link? Is Lucy just a different evolutionary species?

7.  Research and watch a short video clip (youtube, national geographic, CNN news) about Lucy……

·  What video clip did you watch and how long was it?

·  What was one thing you learned from this clip?

·  Did your clip support or dispute “Lucy” as the missing link?

·  Has your opinion changed about Lucy after watching this