Does Giberson and Collins' Neanderthal Argument Demonstrate "Common Ancestry"?
The last few years have seen many comparisons of our own genome to that of other species--all completely consistent with an evolutionary explanation. Recent work on Neanderthals' DNA has been pieced together from several thirty-thousand-year-old bones of different Neanderthal individuals. The DNA similarity to Homo sapiens is striking. ... Precise but unusual variations are found in both our DNA and in the DNA from Neanderthal bones. The data imply interesting evolutionary connections. ... Neanderthals went extinct 30,000 years ago after a period of interbreeding with those humans that migrated out of Africa. The continuing presence of Neanderthal DNA in non-Africans provides evidence of common ancestry for many human groups from this era of interbreeding. Neanderthals are perhaps best understood as a subspecies of Homo sapiens. Compelling evidence of this sort for common ancestry grows almost daily.This may be "compelling evidence" for "common ancestry"--but common ancestry with what? Do Neanderthals represent a decidedly non-human primitive species? Not at all.
(Karl Giberson and Francis Collins, The Language of Science and Faith pp. 43-44 (InterVarsity Press, 2011).)
As noted, Giberson and Collins admit that Neanderthals are "best understood as a subspecies of Homo sapiens," yet somehow they do not elaborate for their readers that this in no way bolsters a general argument for common ancestry. In fact, many experts think that Neanderthals essentially are us, and we are them. As far as evolution is concerned, observing that living humans share common ancestry with Neanderthals might be little more significant than saying we share common ancestry with ancient Europeans.
As a 2007 article in the Washington Post quoted paleoanthropologist Eric Trinkaus saying:
"Given the data we now have, it would be highly improbable to argue there is no Neanderthal contribution to the early European population that came out of Africa," Trinkaus said. "I believe there was continuous breeding between the two for some period of time.The article further reports that Trinkaus' study "concluded that a significant number [of skeletons] have attributes associated with both Neanderthals and the modern humans who replaced them." The article continues stating:
"Both groups would seem to us dirty and smelly but, cleaned up, we would understand both to be human. There's good reason to think that they did as well."
Although Neanderthals live in the public imagination as hulking and slow-witted "Alley Oops," Trinkaus and others say there is no reason to believe they were any less intelligent than the newly arrived 'modern humans.' Neanderthals were stockier and had larger brows, sharper teeth and more jutting jaws, but their brain capacity appears to have been no different than that of the newcomers.
Similarly, a 1999 article in Time magazine reported that there's increasing evidence that Neanderthals were essentially "all just people":
The real message, [a Washington University paleoanthropologist Erik] Trinkaus believes, is that to people living in the Stone Age, Neanderthals were just another tribe. "They may have had heavier brows or broader noses or stockier builds, but behaviorally, socially and reproductively they were all just people."
(Michael D. Lemonick, "A Bit of Neanderthal in Us All?," Time Magazine (April 25, 1999).)
A Nature News article stated explained that Neanderthals may not exactly be extinct:
[I]t may help explain the fate of the Neanderthals, who vanished from the fossil record about 30,000 years ago. "It means Neanderthals didn't completely disappear," says Jeffrey Long, a genetic anthropologist at the University of New Mexico, whose group conducted the analysis. There is a little bit of Neanderthal leftover in almost all humans, he says.
Given the high degree of skeletal similarity between humans and Neanderthals, the notion that we interbred is nothing new. They have been called a possible "race" of our own species, as studies have found their body shape is highly similar to that of modern humans. In addition to the genetic evidence, the discovery of "morphological mosaics" indicates that they likely interbred with modern humans. The finding of a modern-humanlike hyoid bone in a Neanderthal implies that they may have had language capabilities. In fact, there is evidence that they used tools and technology. According to Smithsonian magazine:
Neanderthals, traditionally designated Homo sapiens neanderthalensis, were not only "human" but also, it turns out, more "modern" than scientists previously allowed. "In the minds of the European anthropologists who first studied them, Neanderthals were the embodiment of primitive humans, subhumans if you will," says Fred H. Smith, a physical anthropologist at LoyolaUniversity in Chicago who has been studying Neanderthal DNA. "They were believed to be scavengers who made primitive tools and were incapable of language or symbolic thought."Now, he says, researchers believe that Neanderthals "were highly intelligent, able to adapt to a wide variety of ecologicalzones, and capable of developing highly functional tools to help them do so. They were quite accomplished."
The researchers and others have also found dozens of pieces of sharpened manganese dioxide--black crayons, essentially--that Neanderthals probably used to color animal skins or even their own. In his office at the University of Bordeaux, d'Errico hands me a chunk of manganese dioxide. It feels silky, like soapstone. "Toward the end of their time on earth," he says, "Neanderthals were using technology as advanced as that of contemporary anatomically modern humans and were using symbolism in much the same way."
(Joe Alper, "Rethinking Neanderthals," Smithsonian magazine (June 2003).)
In fact, Neanderthals buried their dead, and they had an average brain size which was slightly larger than that of modern humans. Perhaps it's time to stop seeing Neanderthals as a primitive species--a popular icon of evolution--but rather as a sub-race of our own species. To Giberson and Collins's credit, they recognize this point. But they do not recognize that it therefore prevents Neanderthals from demonstrating that humans share ancestry with something that isn't human.
If Giberson and Collins want to make the case that humans share "common ancestry" with some primitive species, they're going to have to find another example than Neanderthals. Neanderthals do essentially nothing to bolster the case that humans evolved from more primitive hominids.