Evolutionary Back Story: Thoroughly Modern Spine Supported Human Ancestor

Science News ^ | 5-7-2006 | Bruce Bower

[blam]

Evolutionary Back Story: Thoroughly modern spine supported human ancestor

Bruce Bower

Bones from a spinal column discovered at a nearly 1.8-million-year-old site in central Asia support the controversial possibility that ancient human ancestors spoke to one another.

WIDE OPEN. A recently discovered Homo erectus vertebra from central Asia (left) displays a larger spinal cord canal than does a corresponding bone (right) from a skeleton that had been found in Kenya. Meyer

Excavations in 2005 at Dmanisi, Georgia, yielded five vertebrae from a Homo erectus individual, says anthropologist Marc R. Meyer of the University of Pennsylvania in Philadelphia. The finds occurred in previously dated sediment that has yielded several skulls now attributed to H. erectus (SN: 5/13/00, p. 308: Available to subscribers at http://www.sciencenews.org/articles/20000513/fob1.asp).

The new discoveries represent the oldest known vertebrae for the genus Homo, Meyer announced last week at the annual meeting of the Paleoanthropology Society in San Juan, Puerto Rico. The fossils consist of one lumbar, two thoracic, and two cervical vertebrae.

Meyer and his colleagues—David Lordkipanidze and Abesalom Vekua, both of the Georgian State Museum in Tbilisi—compared the size, shape, and volume of the Dmanisi vertebrae with more than 2,200 corresponding bones from people, chimpanzees, and gorillas.

"The Dmanisi spinal column falls within the human range and would have comfortably accommodated a modern human spinal cord," Meyer says.

Moreover, the fossil vertebrae would have provided ample structural support for the respiratory muscles needed to articulate words, he asserts. Although it's impossible to confirm that our prehistoric ancestors talked, Meyer notes, H. erectus at Dmanisi faced no respiratory limitations on speech.

In contrast, the 1984 discovery in Kenya of a boy's 1.6-million-year-old skeleton, identified by some researchers as H. erectus and by others as Homo ergaster, yielded small, chimplike vertebrae. Researchers initially suspected that the ancient youth and his presumably small-spined comrades lacked the respiratory control to talk as people do today.

In the past 5 years, investigators including Bruce Latimer of the Cleveland Museum of Natural History have suggested that the prehistoric boy offers a misleading view of H. erectus' backbone. They contend that growth of the bony canal encasing his spinal cord had been stunted, and spinal cord compression would have impeded his movement and caused limb weakness.

Finding ancient, humanlike vertebrae at Dmanisi fits with Latimer's view, Meyer says. Infant malnutrition, which often arrests growth of the human vertebral canal, may have affected the H. erectus youth, Meyer suggests.

The ancient boy, who died at age 10 or so, would have required intensive protection and provisioning, Meyer asserts. "Both altruism and spoken language may have been part of the behavioral repertoire of early Homo," the Pennsylvania researcher says.

The modern-looking vertebrae at Dmanisi, remarks David Frayer of the University of Kansas in Lawrence, comport with earlier fossil-skull studies indicating that early Homo possessed a speech-ready vocal tract.

Robert C. McCarthy of Florida Atlantic University in Boca Raton disagrees. At the Paleoanthropology Society meeting, he presented vocal-tract reconstructions for various ancient Homo species suggesting that the capacity to articulate speech as well as people do now emerged exclusively in Homo sapiens around 50,000 years ago.

Before then, all members of the Homo genus—including H. sapiens—possessed a short set of neck vertebrae, resulting in a vocal tract with a restricted range of speech sounds, McCarthy and his coworkers argue.

Many populations today, including Australian aborigines, possess neck vertebrae comparable in length to those that McCarthy's team considered inadequate for modern speech, Meyer responds.

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[blam]

GGG Ping.

Here's a 2003 article from Scientific American about this discovery in the Republic Of Georgia.

Stranger In A New Land

Image: JOHN GURCHE PORTRAIT OF A PIONEER With a brain half the size of a modern one and a brow reminiscent of Homo habilis, this hominid is one of the most primitive members of our genus on record. Paleoartist John Gurche reconstructed this 1.75-million-year-old explorer from a nearly complete teenage H. erectus skull and associated mandible found in Dmanisi in the Republic of Georgia. The background figures derive from two partial crania recovered at the site.

[uncitizen]

Put a pair of specs on that guy and i'd swear i was looking at Alan Colmes.

[Dawggie]

Hey, I think your right!

[xJones]

Homo erectus, what else is new? And it's nonsense to think that an advanced back bone is required for speech. Al Gore and Jimmy Carter, for instance, never shut up and neither one has any back bone.

[CzarNicky]

in other news no spines were found in the Republican section of Congress.

[Mr. Brightside]

Looking at Congressional Republicans, the spine gene must skip a few generations.

[Sacajaweau]

Why would one even think that early humans didn't talk to each other...in some form? Babies cry....That's a way of talking. The problem is developing a common language.

I contend that man was never an idiot and if the world started all over...it would go through an almost identical learning process. The most important thing remains interaction between human beings...the old "two heads are better than one". It's the struggle for "agreement" that drives us.

[blam]

"I contend that man was never an idiot and if the world started all over...it would go through an almost identical learning process. "

My thoughts too.

[ClaudiusI]

Huh, huh, huh, he said "erect".

[GSlob]

I'd contend the opposite - that the man is, and has always been, an idiot. The key is in the relatively rare less- and non- idiotic exceptions.

[balrog666]

Are a small number of barks and hoots "words"?

[Sender]

The day the mighty warriors laid down their spears and picked up an intern and an expense account, their spines began to atrophy.

[freedumb2003]

Are a small number of barks and hoots "words"?

If they had the same meaning to the receiver as the sender, sure.

[freedumb2003]

2 seconds apart!!

Pretty spooky ;)

Also true.

[PatrickHenry]

Ping. But it's a blam thread, so I won't deploy the list.

[somemoreequalthanothers]

I contend that man was never an idiot

Correct.

With the exception of Republicans that have a majority in both houses of congress and the executive branch but can't seem to push any conservative agenda.

[elmer fudd]

I contend that man was never an idiot and if the world started all over...it would go through an almost identical learning process.

Idiots of any species don't live long in the wild. Even animals that we regard as dumb tend to be quite canny in their behavior. They can't afford to be dumb unless they are domesticated.

[SunkenCiv]

Thanks Blam.

To all -- please ping me to other topics which are appropriate for the GGG list. Thanks.

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[Ernest_at_the_Beach]

Thanks for the ping!