Scientists studying a 4.4-million-year-old fossil named Ardi may have uncovered the evolutionary step ["missing link"] that turned ancient [nonhuman] climbers into early [human-hybrid] walkers
Here’s what there is to learn when reading this Popular Mechanics' story:
- Ardi is the oldest known partial skeleton of a hominin and shows foot features that are transitioning from vertical climbing to bipedal walking.
- While Ardi has the primitive grasping big toe of the more apelike human ancestors that came before her, other parts of her feet are more evolved.
- It is Ardi’s talus, a bone in the ankle, that lies somewhere between the morphology of the same bone in apes and humans.
Besides our much larger brains and visibly obvious differences, such as facial [structure and] features, one thing we evolved to be much more adept at than chimps and gorillas (which we, according to Darwinism, diverged from millions of years ago) is walking on two feet.
But just when did human predecessors first descend from the trees and walk upright?
A 4.4-million-year-old female skeleton named Ardi may answer that question. Predating even the iconic Lucy (Australopithecus) by a million years, she belongs to the species Ardipithecus ramidus and is revealing more about our human origins and how we became bipedal.
Unearthed in the Ethiopian desert back in 1994, Ardi is the oldest known partial hominin skeleton, though her species has been known since 1925 under the name Australopithecus ramidus.
Biological anthropologist Thomas Prang of Washington University in St. Louis and his research team discovered that Ardi was able to walk upright but still retained a grasping foot and other apelike features.
“Our observations of the human and ape fossil record are inconsistent with recently proposed models of human origins, which envision the last common ancestor of humans and chimpanzees as a generalized arboreal ape,” he said in a study recently published in Communications Biology.
“Instead, our results strongly imply that humans evolved from an African ape-like ancestor.”
- Related video: 300,000-year-old fossils: The true origin of Homo sapiens (History with Kayleigh Official) My name is Kaylee, and I guess it's safe to... (13:41)
This is part of a larger clade that gorillas also belong to. It has been argued that Ar. ramidus was more humanlike than apelike and had already evolved out of climbing trees vertically and dropping to all fours and walking on its knuckles in order to get around on land.
What Dr. Prang found was that Ardi is a mashup of primitive and modern features. She has a big toe designed for grasping branches, but other features of her feet, cranial base, and pelvis suggest that her species was adapting to bipedalism.
There is one bone that especially stands out: Ardi’s talus, a bone in the ankle which is also the second largest bone in the back of the foot. It transfers body weight between the lower leg and foot and helps African apes climb.
The talus enables dorsiflexion, or the backwards flexing of the foot, and inversion, the sideways turning of the foot. Both put the animal’s center of mass in a position closer to support, so apes are at much less risk of suffering lethal backward falls.
In ape species that primarily climb trees and primarily use dorsiflexion for vertical climbing, the forefoot is shorter than those of bipeds and quadrupeds, so Dr. Prang’s team turned its focus to the front of Ardi’s foot and also figured out her approximate body mass using the widths of the talar trochlea, or the upper joint surface of the talus.
There have been previous arguments that the morphology of the talar trochlea may not be the greatest indicator of how apes and early humans moved. Gorillas, chimps, bonobos, and gibbons have short forefeet for their body masses, while orangutans and larger monkeys have the longest forefeet.
The human forefoot is longer than those of chimps and gorillas and shorter than those monkeys, but there is still some overlap with bonobos. More
Michael Cremo, the Forbidden Archeologist, has something to say to the contrary: Human life is FAR older on this earth (bhumi) than science yet admits. And "modern humans" are a misnomer because we are far older, according to ooparts and other pieces of inconvenient (and suppressed) evidence in the fossil and archeological record: We are not evolving but devolving and have been for hundreds of millions of years (in yugas and kalpas as declared by the Dharmic religions).
Extraterrestrials have intervened many times. - Popular Mechanics via MSN.com, She Was Half Ape, Half Human—and She May Hold the Secret to What Makes Us Who We Are; Eds., Wisdom Quarterly
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