Navigation Links
Oldest Skeleton in Human Family Tree Surprises Scientists
Date:10/1/2009

Experts say finding challenges theory that ancestors were like chimps, apes

THURSDAY, Oct. 1 (HealthDay News) -- New details about the oldest skeleton from the human family tree suggest that human evolution was much more complicated than ever imagined.

Fossil remains of "Ardi," a female member of the hominid species Ardipithecus ramidus who lived 4.4 million years ago, do not resemble a chimp, as was long supposed.

Instead, Ardi was a combination of the features of chimps, humans and other creatures.

"Our ancestors didn't come from something that looked like a chimp, and we now have a very good picture of what it was like and what kind of environment it lived in," said Leslea Hlusko, associate professor of integrative biology at the University of California Berkeley. "Our last common ancestor [shared with chimpanzees] was not a monkey but a different primate. It wasn't a human and it wasn't a chimp. It was something else."

Hlusko is one of the researchers publishing a series of 11 articles about Ardi and her environment in the Oct. 2 issue of Science.

"This is earth-shaking. It challenges the simple paradigm that we've had for a long time of our earliest ancestors being very chimp- or gorilla-like," added Jeffrey Laitman, director of the Center for Anatomy and Functional Morphology at Mount Sinai School of Medicine in New York City. "Now we have this odd beast that is tantalizingly closer to the elusive last common ancestor, and already it's showing features that are different than chimps and gorillas, and in some cases closer to humans."

The findings also suggest that chimps and gorillas have followed their own evolutionary path, quite separate from humans.

"This is sort of a declaration of independence for gorillas and chimps. They're not just transitional types of humans," Laitman said.

Fossil remains of Ardi, who weighed about 110 pounds and stood close to four-feet tall, were first discovered in a remote part of northeastern Ethiopia in 1994. She is 1.2 million years older than "Lucy," an Australopithecus, who, until now, was the earliest existing evidence of the path of human evolution.

It has taken 17 years for scientists to piece together a portrait of Ardi's life and times.

Ardi has smaller canines than chimps, was able to walk on two feet on the ground and, thanks to a "grasping big toe," could also travel easily in trees. Her limbs and hands more closely resembled those of now-extinct apes.

And the fragments of Ardi's skeleton had remained in the same place for 4.4 million years. "Where the animal fell to the ground was where it got buried," said Hlusko. "The animal and plant material stayed exactly where it fell, which is just amazing."

This enabled Giday WoldeGabriel, another author on the papers and a geologist with Los Alamos National Laboratory in New Mexico, to accurately (give or take 60,000 or 80,000 years) pinpoint a date using three different methodologies.

"We made sure they hadn't been moved or mixed with something else," said WoldeGabriel, who is originally from Ethiopia.

Researchers were also able to reconstruct Ardi's environment to a degree not possible for Lucy, because bits and pieces of her history had long been washed away or moved.

Ardi lived in a forested area with grasslands possibly several miles away. This detail challenges one school of thought which holds that bipedalism came about as a response to living in grasslands.

Scientists also found thousands of specimens from small mammals in the area, along with indications of fig trees, birds (including owls and parrots) and larger mammals such as elephants and giraffes.

Ardi is not the last common ancestor but she is "tantalizingly close," Laitman said.

"It's showing us that if you went even earlier and found the Great Elusive One, that that individual would give rise to distinctive features of chimps and gorillas and distinctive features of Ardi and eventually us," he added. "That's why this is such a tantalizing paradigm shift. It's telling us that the template we were all looking at was too simplistic. This is really going to shake a lot of tree branches."

More information

The University of California Museum of Paleontology has more on evolution.



SOURCES: Leslea Hlusko, Ph.D., associate professor, integrative biology, University of California Berkeley; Giday WoldeGabriel, Ph.D., geologist, technical staff member, Los Alamos National Laboratory, Los Alamos, N.M.; Jeffrey Laitman, Ph.D., professor and director, Center for Anatomy and Functional Morphology, Mount Sinai School of Medicine, New York City; Oct. 2, 2009, Science


'/>"/>
Copyright©2009 ScoutNews,LLC.
All rights reserved

Related medicine news :

1. Exercise Benefits Even the Oldest Old
2. Barry Bloom, Jeffrey Sachs to Be Honored for Introducing Modern Solutions to The Worlds Oldest Problems: Poverty And Disease
3. Oldest Heart Patients May Get Most From Warfarin
4. New Cases of Alzheimers and Dementia Continue to Rise, Even in the Oldest Old
5. New cases of Alzheimers and dementia continue to rise, even in the oldest old
6. Structures from the human immune systems oldest branch shed light on a range of diseases
7. Worlds oldest woman had normal brain
8. Cullen Elected to Chairman of YMCA of Metro Detroit - the Citys Oldest Not-for-Profit
9. DNA Find in Oregon Is Oldest Yet Discovered in Americas
10. Coalition of Caregivers Warns Congress of Danger to Oldest U.S. Seniors if Medicare Slashed
11. Nfocus Neuromedical Announces US Clearance of Unique Guiding Catheter with Uni-body Internal Skeleton
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:6/26/2016)... , ... June 26, 2016 , ... ... once they have been diagnosed with endometriosis. These women need a treatment plan ... require a comprehensive approach that can help for preservation of fertility and ultimately ...
(Date:6/25/2016)... ... June 25, 2016 , ... "With 30 hand-drawn hand gesture animations, FCPX users ... - CEO of Pixel Film Studios. , ProHand Cartoon’s package transforms over 1,300 ... Pro X . Simply select a ProHand generator and drag it above media or ...
(Date:6/25/2016)... ... 25, 2016 , ... On Friday, June 10, Van Mitchell, Secretary of the ... to iHire in recognition of their exemplary accomplishments in worksite health promotion. , The ... Health & Wellness Symposium at the BWI Marriott in Linthicum Heights. iHire was one ...
(Date:6/24/2016)... (PRWEB) , ... June 24, 2016 , ... June 19, ... the dangers associated with chronic pain and the benefits of holistic treatments, Serenity ... who are suffering with Sickle Cell Disease. , Sickle Cell Disease (SCD) is a ...
(Date:6/24/2016)... ... June 24, 2016 , ... ... for accelerated orthodontic treatment. Dr. Cheng has extensive experience with all areas of ... AcceleDent, and accelerated osteogenic orthodontics. , Micro-osteoperforation is a revolutionary adjunct to ...
Breaking Medicine News(10 mins):
(Date:6/24/2016)... Research and Markets has ... 2015-2025: Applications, Technologies, Forecasts" report to their ... Electronics, Smart Skin, Structural Health Monitoring, Composite Smart ... electronics involves electronic and/or electrical components and circuits ... structures such as vehicle bodies or conformally placed ...
(Date:6/24/2016)... -- Research and Markets has announced the addition ... report to their offering. ... The World Market for Companion Diagnostics covers the world ... in the report includes the following: , ... by Region (N. America, EU, ROW), 2015-2020 , World ...
(Date:6/24/2016)... Tenn. , June 24, 2016  Arkis ... providing less invasive and more durable cerebrospinal fluid ... in funding.  The Series-A funding is led by ... Lighthouse Fund, and other private investors.  Arkis, new ... neurosurgical instrumentation and the market release of its ...
Breaking Medicine Technology: