Pondering the "Lucy" Myth over Coffee

Molecular History Research Center - http://www.mhrc.net/mitochondrialEve.htm

"In 1987, A world wide survey of human mitochondrial DNA (mtDNA) was published by Cann, Stoneking, and Wilson in Nature magazine. Its main point was that "all mitochondrial DNAs stem from one woman" and that she probably lived around 200,000 years ago in Africa. When the media picked up from Wilson, one of the authors of the paper, that they had found the "Mitochondrial Eve" or "African Eve", the story became a sensation."

The critics of the Eve story, saw that the mitochondrial data did not fit with the fossils in the field that show a multi-regional continuity, so they started voicing several complaints against the mitochondrial data:
  • The mitochondrial data was determined using restriction analysis rather than DNA sequencing. Restriction analysis is an enzymeatic method which can give false results at times.
  • They used African Americans rather than Africans from Africa to represent native Africans in their study. So they did not get a proper sampling of the African population.
  • They used an inferior method to build a phylogenetic tree. They used a program called PAUP which had been written to determine evolutionary relationships. However, the program gave different results when you entered the data in a different order. The answer was dependant upon the order that the data was entered into the computer. A big problem!
"Blair Hedges and his group in Penn State, found that when the data was entered in different orders, that sometimes some other part of the world was indicated as the place where Eve lived, rather than Africa."


NBC news ran this story from the AP (Associated Press) in 2009 debunking the Lucy theory: http://www.nbcnews.com/id/33110809/ns/technology_and_science-science/t/worlds-oldest-human-linked-skeleton-found/#.VsUpr-ZrmSo

"The story of humankind is reaching back another million years with the discovery of “Ardi,” a hominid who lived 4.4 million years ago in what is now Ethiopia.

The 110-pound, 4-foot female roamed forests a million years before the famous Lucy, long studied as the earliest skeleton of a human ancestor.

This older skeleton reverses the common wisdom of human evolution, said anthropologist C. Owen Lovejoy of Kent State University.

Rather than humans evolving from an ancient chimplike creature, the new find provides evidence that chimps and humans evolved from some long-ago common ancestor — but each evolved and changed separately along the way."

Some details about Ardi in the collection of papers:

  • Ardi was found in Ethiopia’s Afar Rift, where many fossils of ancient plants and animals have been discovered. Findings near the skeleton indicate that at the time it was a wooded environment. Fossils of 29 species of birds and 20 species of small mammals were found at the site.
  • Geologist Giday WoldeGabriel of Los Alamos National Laboratory was able to use volcanic layers above and below the fossil to date it to 4.4 million years ago.
  • Ardi’s upper canine teeth are more like the stubby ones of modern humans than the long, sharp, pointed ones of male chimpanzees and most other primates. An analysis of the tooth enamel suggests a diverse diet, including fruit and other woodland-based foods such as nuts and leaves.
  • Paleoanthropologist Gen Suwa of the University of Tokyo reported that Ardi’s face had a projecting muzzle, giving her an ape-like appearance. But it didn’t thrust forward quite as much as the lower faces of modern African apes do. Some features of her skull, such as the ridge above the eye socket, are quite different from those of chimpanzees. The details of the bottom of the skull, where nerves and blood vessels enter the brain, indicate that Ardi’s brain was positioned in a way similar to modern humans, possibly suggesting that the hominid brain may have been already poised to expand areas involving aspects of visual and spatial perception.
  • Ardi’s hand and wrist were a mix of primitive traits and a few new ones, but they don’t include the hallmark traits of the modern tree-hanging, knuckle-walking chimps and gorillas. She had relatively short palms and fingers which were flexible, allowing her to support her body weight on her palms while moving along tree branches, but she had to be a careful climber because she lacked the anatomical features that allow modern-day African apes to swing, hang and easily move through the trees.
  • The pelvis and hip show the gluteal muscles were positioned so she could walk upright.
  • Her feet were rigid enough for walking but still had a grasping big toe for use in climbing.
  • The research was funded by the National Science Foundation, the Institute of Geophysics and Planetary Physics of the University of California, Los Alamos National Laboratory, the Japan Society for the Promotion of Science and others.