Many Groups of Archaic Humans

 

Mary and Louis Leakey in 1962.

“People frequently ask me why I devote so much time to seeking out facts about man’s past…the past shows clearly that we all have a common origin and that our differences in race, color, and creed are only superficial.”-Louis Leakey

Louis S.B. Leakey was an African-born English anthropologist. He was born Aug. 7, 1903, in Kabete, Kenya. His parents were Anglican missionaries among the Kikuyu people of East Africa. Louis and his second wife Mary established an excavation site at Olduvai Gorge to search for fossils. The team made unprecedented discoveries of hominids millions of years old, including H. habilis and H. erectus. Leakey died on October 1, 1972.

Louis and Mary Leakey's legacy cannot be overstated. Their work had a tremendous impact on our understanding of human origins. The Leakeys recognized that there were various archaic humans living millions of years ago. In 1965, Louis Leakey wrote:

"Current findings on human evolution have brought us to the position where much of what we believed to have theoretically happened proves to be incorrect. Much that is in the textbooks, much that is still being taught in universities about human evolution is no longer true, but it continues to be taught because the implications of recent discoveries are insufficiently understood.

It was principally Weidenreich, Le Gros Clark, and a few of the people of that generation, just previous to mine, who put forward and strongly defended the idea that man had gone through a very simple series of stages of evolution: the pongid stage, an Australopithecine stage, a Pithecanthropus stage, and then man as we know him today. Theoretically, this had always seemed highly unlikely to some of us, since it meant that man had done something which no other mammal had done: evolved in a single straight line instead of having one main branch, with many experimental side branches which failed to make the grade. Yet the old theory persists. Linked with it is the concept, still very, very widely taught and very widely believed, that man in the relatively near past was at a pongid or ape stage of evolution. In such a very short time, three or four million years, as the books and many of my colleagues put it, we are supposed to have lost our huge canine teeth, lost our simian shelves, lost our long, brachiating arms, ceased to dwell in the trees, and many other similar but, I fear, erroneous concepts. These were theories which in the light of current facts no longer stand up."

Mary Leakey’s 1979 discoveries of footprints in Tanzania added to the evidence that humans walked the earth over 3 million years ago. At Laetoli, about 25 miles south of Olduvai Gorge in Tanzania, Leakey discovered footprints of a man, woman and child created about 3.6 million years ago and preserved under falling ash from the nearby Sadiman volcano. The raised arch and rounded heel of the footprints showed that whoever left these footprints walked as humans walk today.

When Jeremy DeSilva compared the ankle joint, the tibia and the talus fossils of human ancestors ("hominins") between 4.12 million to 1.53 million years old, he discovered that all of the ankle joints resembled those of modern humans rather than those of apes. Chimpanzees flex their ankles 45 degrees from normal resting position. This makes it possible for apes to climb trees with great ease. While walking, humans flex their ankles a maximum of 20 degrees. The human ankle bones are quite distinct from those of apes. (Read about DeSilva’s research here.)

A recent discovery of a complete fourth metatarsal of A. afarensis at Hadar that shows the deep, flat base and tarsal facets that "imply that its midfoot had no ape-like midtarsal break. These features show that the A. afarensis foot was functionally like that of modern humans." (Carol Ward, William H. Kimbel, Donald C. Johanson, Feb. 2011) Read the report here.

Related reading: Louis Leakey: Scientist of the Day; 1.5 Million-Year Human Footprints in Kenya; Neanderthal Humans; Many Groups of Archaic Humans; Time to Jettison Young Earth Creationism; Was Lucy Human?; Ego's role in presentation of human origins