The Mosaic of Human Origins
April 17, 2013 at 11:11 am
(This post was last modified: April 17, 2013 at 11:12 am by pocaracas.)
Anthropology in the making... all creationists should read!
http://blogs.scientificamerican.com/prim...n-origins/
http://blogs.scientificamerican.com/prim...n-origins/
Quote:
[...]In 2008 a paleoanthropologist at the University of Witwatersrand in Johannesburg, South Africa, by the name of Lee Berger unearthed the fossils of a juvenile male and adult female on the Malapa Nature Reserve after his son accidentally stumbled across their remains while chasing his dog. Berger classified the species as Australopithecus sediba—meaning “southern ape” in a mixture of Latin and Greek combined with the local South African SeSotho word for “wellspring.” Both specimens were remarkably complete given their advanced age of 1.977 million years and placed the species as a possible descendant of Australopithecus africanus, which lived in the same region from about 3.03 to 2.04 million years ago (mya). But once Berger’s team of researchers published their analysis in the journal Science in 2010 suggesting that Au. sediba was the direct ancestor of Homo—and ultimately humans—their interpretation has been enormously controversial within the field.
[...]
“There are a couple of reasons for this,”
[...]
“One reason is just the historical precedent for researchers to see East Africa as the place where all the evolutionary action is,” Churchill said.
In fact, nearly every hominin species ever found has been unearthed in that region with most of the material discovered in Ethiopia, Kenya, and Tanzania. These include Au. afarensis (3.9 – 2.9 mya), famously known as Lucy, Homo habilis (2.33 – 1.4 mya), the earliest species to be morphologically similar enough to be included in our genus, and our direct ancestor Homo erectus (1.8 mya to about 300,000), the first hominin to leave our ancestral home and radiate west to Spain and east as far as Indonesia. Given the diversity of species and the adaptive radiation that occurred from East Africa, this is a historical precedent that is hard to dismiss.
“Secondly there is the issue of time,” Churchill continued. “Most people would say that Homo originates somewhere on the order of 2.3 million years ago.” This predates Au. sediba by more than 300,000 years, meaning that unless you plan to argue from the point of view of Wordsworth that “the child is father of the man,” it is a difficult issue to reconcile. However, this early date for the genus Homo is based on a single maxilla fossil (the two bones that form the roof of the mouth), designated AL 666, and was originally discovered smashed into fragments.
[...]
“The conflict is not time,” said John Hawks, an associate professor of anthropology at the University of Wisconsin-Madison who was not involved in the current study. “The conflict is anatomy. The anatomies of the early fossils that are candidates for Homo are not like Au. sediba.”
[...]
“The reason why these researchers are emphasizing the mosaic nature of Au. sediba so much,” said Hawks, “is that it is evident in these skeletons that you have features that shouldn’t go together. If you looked at only one part you would come to a very different conclusion than looking at the whole.”
[...]
These results suggest that the priority of interpretation should go to the more complete fossil skeletons and highlights the problematic nature of basing conclusions on fragmentary evidence. Reflecting on this mosaic of bones ultimately challenges us to reconsider the pride with which we have told the story of human origins. In this way, Australopithecus sediba reveals what the Capuchin monks spent more than three centuries creating their own mosaic to express. The whole truly is greater than the sum of its parts.
