Afarensis is a 3.5-2.8 million year old hominin from the Kada Hadar member of the Hadar formation in the Middle Awash, Ethiopia. He is approximately 41 inches tall, weighs approximately 60 pounds and has a cranial capacity of a whopping 410 cc (approximately). Afarensis is currently considered to be transitional between apes and humans and displays some traits of both. Since he spends a lot of time on the couch watching monster movies, some observers question whether he is an obligate biped (although no one has observed him climbing a tree). He also has a blog called 
Razib has rounded up a lot of the posts on the recent Neanderthal news. Kambiz has also written the first of a multipart series on the subject. MSNBC is also reporting that twom different papers will be published on the subject of Neanderthal DNA. One, by the Paabo group, will be pubished in Nature. The other, by a group headed by Rubin, will be published in Science. Apparently, over a million bases have been identified (note this is not mtDNA). That being the case, I thought I would start some background posts to try and demonstrate how this will impact our views on Neanderthals.
I don't propose to go into a lot of the material that has already been covered. Suffice to say, people have been arguing over the place of Neandethals since the time of Virchow. This type of argumentation reached it's peak in C. Loring Brace's article The Fate of the "Classic" Neanderthals: A Consideration of Hominid Catastrophism published in Current Anthropology back in 1964. The issues Brace discussed back then still play a role in the current debate, but there are other issues that have arisen since that play a role. When I was in college the "must read" paper on Neandethals and the origins of modern humans was a paper by Smith, Falsetti and Donnelly - Modern Human Origins - published in the 1989 Yearbook of Physical Anthropology. The paper summarized three different models for the origins of modern humans.
The first, called the Afro-European Sapiens (AES) model was advocated by Gunter Brauer. According to the AES modern humans evolved from an early archaic Homo sapiens stage. This stage is represented by finds at Bodo:
and Kabwe:
As well as Ndutu, Eyasi and Elandsfontein.This early group gave rise to a population transitional between them and early modern Africans. The transitional group is represented by finds in Florisbad:
and Omo (specifically Omo 2):
As well as Ngaloba. According to this scenario modern humans then moved out of Africa through a gradual process due to climate and environmental change. The AES does not view this as a biological speciation event. Consequently, expanding modern populations could assimilate "archaic" genes into their gene pool.
The second model is the Recent African Evolution (RAE) model. Also called the Out of Africa model, it's primary advocates are Stringer and Andrews. (I will have more to say about this below) The RAE model proposes that modern humans arose in Africa within the last 200, 000 years and spread around the globe, replacing other populations as they went. In this model the origin of modern humans was definately a speciation event. Advocates of RAE do not, consequently allow for any kind of assimilation of archaic genes - or at least don't think it had a significant impact on human evolution
The third model is the Multiregional Evolution (MRE - aka mulitregional continuity) model. Argues that there is a large amount of morphological and genetic (and aruably cultural) continuity throughout Eurasia and Africa. As Smith et al put it:
This would mean that paleontological indications of continuity, particularly transitional fossils and regionally distinct morphological features linking archaic and modern humans in specific geographic regions, should be found in Eurasia as well as Africa, but not necessarily that such indications should be common...or that significant continuity characterizes every region.
For the most part the AES has been collapsed into the MRE and the debate has largely focussed on MRE vs. RAE. In the next post I will take a closer look at the RAE.
Comments
I never knew that Afro-European Sapiens was anything but part of MRE. And I always thought Gunter Brauer was an advocate of anything close to MRE. However, this was in 1989, and a lot has changed since then. And I suppose we must all allow for that.
Anne G
Posted by: Anne Gilbert | November 15, 2006 8:14 PM
The Anthro dept I was in was heavily MRE and considered AES Out of Africa Lite. Too much Africa and not enough continuity. At any rate, I think AES is probably closer to what the genetics people are saying...
Posted by: afarensis, FCD | November 15, 2006 10:21 PM