3.3 Million-Year-Old Fossil Shows How The Spine Evolved

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jstan

climber
Topic Author's Original Post - May 24, 2017 - 01:57pm PT
Before he became a world traveler Henry used to spend time at Philadelphia’s zoo watching the apes climb. Close reading of the article below suggests our physiology is not as well adapted for climbing as that of the apes. We have fewer ribs and a longer lower back; and so fewer attachment points for thorasic muscles. And increased vulnerability to bouldering caused lower back pain.

3.3 Million-Year-Old Fossil Sheds Light On How The Spine Evolved
May 23, 20176:17 PM ET
MERRIT KENNEDY

This is a vertebrae of the Selam skeleton.
Zeray Alemseged, University of Chicago


A remarkably complete fossil of a young child suggests that key elements of the human spinal structure were already in place in an ancient human relative 3.3 million years ago.

The child, about three years old, likely died suddenly and quickly drifted into a body of water, where she was covered in sediment that eventually hardened to sandstone, Zeray Alemseged of the University of Chicago tells The Two-Way.
His team found the well-preserved fossil in 2000 in Dikika, Ethiopia, and for years they have been painstakingly excavating it, revealing what they say is the only known backbone with completely preserved bones of the middle and upper back dated prior to 60,000 years ago. Their findings were recently published in the Proceedings of the National Academy of Science.
Now, Alemseged says this shows "that the human type of segmentation and numbering of our backbone emerged 3.3 million years ago, and this fossil provides us for the first time the hard evidence, the fossil evidence, to confirm that indeed the structure is as ancient as we're claiming it now to be."
The fossil is nicknamed Selam, which means "peace" in Ethiopian Amharic. She is from an early human relative species called Australopithecus afarensis. The famous Lucy fossil is also from this species.






The full skeleton of Selam, including the spinal column.
Zeray Alemseged, University of Chicago
The spines of our early ancestors have been mysterious. They are not well preserved in the fossil record, Alemseged explains, because they are much more fragile than other parts of the animal, like teeth.
This specimen is particularly unique, because it belongs to a child whose individual vertebrae are "still in the process of fusing and forming." He says that's why "the data is so unique, shedding light on one of the key milestone events in human evolution and that is the transition from the more ape-like arrangement of the backbone to the more humanlike arrangement of the backbone."
The specimen has the same number of neck (seven) and mid-back vertebrae (12) as modern humans, while African apes have 13 mid-back vertebrae.
It is well-established that this species walked upright on two legs (though there's some debate about how much time they spent climbing). But this backbone sheds more light on how they moved.
"The specimen says yes, they had the ability to walk like we do today, like humans, but there are some minor differences," Alemseged says. "Particularly the transition from the middle part of the backbones to lower part of the backbone, showing that they may have been good walkers, upright like us, but they were clearly not the runners and the endurance walkers that humans are today."
That's because they "don't seem to have the ability to rotate their backbone, even though they had the ability to extend and flex their backbone," he says.
Scientists spent 13 years working on the fossil at Ethiopia's National Museum; it later traveled to Grenoble, France, for high-resolution imaging.

THE TWO-WAY
New Evidence Suggests Humans Arrived In The Americas Far Earlier Than Thought
"It's a good example of how much effort you have to put in to get high-quality and reliable information," says Bernard Wood, a paleoanthropologist at George Washington University who was not involved in the research. "It's an excellent piece of science."
He described the fossil found at Dikika as the "gift that keeps on giving," because its completeness allows researchers to be quite sure about their conclusions. It's high praise for research on ancient fossils, where findings are often highly controversial.
Richard Potts, the director of Smithsonian's Human Origins Program, echoed the sentiment, calling it an "excellent job of analysis and interpretation." At the same time, he stressed that other, less-complete vertebrae, such as fossils found in Sterkfontein, South Africa, have previously suggested that a humanlike species more than 2 million years old had some of the same spinal features.

At the risk of appearing whimsical we may look into the future to see how we will evolve in the next million years. Walking is now a rare event among humans while climbing is becoming commonplace. Our spines may revert to the three million year old configuration and our skin will necessarily adapt for good adhesion to plastic. We may however speciate into two populations. The 1% population spends an inordinate amount of time flying and so will develop feathers. The 99% population, when not climbing, will need to develop an efficient mode for crawling.
Studly

Trad climber
WA
May 24, 2017 - 02:02pm PT
or could be part of a ape.
c wilmot

climber
May 24, 2017 - 03:34pm PT
Perhaps one day they will learn how to fix it
Gary

Social climber
Desolation Basin, Calif.
May 24, 2017 - 06:04pm PT
Poor little girl.
Norton

Social climber
May 24, 2017 - 06:31pm PT
more Fake News from the supposedly scientific community..
BLUEBLOCR

Social climber
joshua tree
May 24, 2017 - 06:34pm PT
I'm still trying to get my tail back, let alone some ribs and shit;)

I think tails are underrated
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