Media Goes Ga-Ga Over Baby Australopithecine Fossil
An exciting find was recently reported as scientists discovered what may be the most complete australopithecine fossil specimen ever found. It is reported to be a toddler. Unfortunately, the media is misrepresenting this fossil as if it closely mimics humans. Consider the diagram below which comes from the Seattle Times ("Scientists Find Fossil Child from 3.3 Million Years Ago," Thursday Sept. 21, 2006, pg. A2):
Does Australopithecus afarensis really look so similar to humans? This diagram is extremely misleading. Consider a diagram from an actual scientific paper which reveals the stark differences between Australopithecus (right) and the earliest members of our genus, Homo (left):
(From http://www.umich.edu/~newsinfo/Releases/2000/Jan00/r011000b.html covering the Hawks et al. paper)
The media is calling this baby fossil "a mixture of ape-like and human-like features," yet that description obscures the real picture. A recent study in the Journal of Molecular Biology and Evolution found that Homo and Australopithecus differ dramatically:
We, like many others, interpret the anatomical evidence to show that early H. sapiens [H. erectus and H. ergaster] was significantly and dramatically different from ... australopithecines in virtually every element of its skeleton and every remnant of its behavior.
(J. Hawks et. al, "Population Bottlenecks and Pleistocene Evolution," Journal of Molecular Biology and Evolution, 17(1):2-22 (2000).)
Noting these many changes, the study called the evolutionary origin of humans, "a real acceleration of evolutionary change from the more slowly changing pace of australopithecine evolution" and noted that this transformation must have included radical changes:
The anatomy of the earliest H. sapiens [H. erectus and H. ergaster] sample indicates significant modifications of the ancestral genome and is not simply an extension of evolutionary trends in an earlier australopithecine lineage throughout the Pliocene. In fact, its combination of features never appears earlier...
These rapid, unique, and genetically significant changes are termed "a genetic revolution" where "no australopithecine species is obviously transitional." One commentator proposed this evidence implies a "big bang theory" of human evolution. Now that "Homo" habilis is best recognized as an australopithecine due to its ape-like skeletal structure (see "The Human Genus," Science, 284:65-71), it is no wonder an article in Nature last year recognized the lack of a clear-cut immediate ancestor for our genus Homo:
H. ergaster marks such a radical departure from previous forms of Homo (such as H. habilis) in its height, reduced sexual dimorphism, long limbs and modern body proportions that it is hard at present to identify its immediate ancestry in east Africa. Not for nothing has it been described as a hominin "without an ancestor, without a clear past"
(Robin Dennell & Wil Roebroeks, "An Asian perspective on early human dispersal from Africa," Nature Vol 438: 1099-1104 (Dec. 22/29, 2005) (internal citations removed) (emphasis added))
This new baby Australopithecine find is surely exciting and will expand our knowledge of the extinct genus of Australopithecine apes (Australopithecus literally means "Southern Ape"). But don't let misleading diagrams in the media make you think that these apes were clear-cut similar ancestors of our genus Homo.