Handsome by Chance

Chance, not natural selection, best explains why the modern human skull looks so different from that of its Neanderthal relative, according to a new study led by Tim Weaver, assistant professor of anthropology at UC Davis.

The study appears in the August issue of the Journal of Human Evolution.

"For 150 years, scientists have tried to decipher why Neanderthal skulls are different from those of modern humans," Weaver said. "Most accounts have emphasized natural selection and the possible adaptive value of either Neanderthal or modern human traits. We show that instead, random changes over the past 500,000 years or so – since Neanderthals and modern humans became isolated from each other – are the best explanation for these differences."

Weaver and his colleagues compared cranial measurements of 2,524 modern human skulls and 20 Neanderthal specimens, then contrasted those results with genetic information from a separate sample of 1,056 modern humans.

The scientists concluded that Neanderthals did not develop their protruding mid-faces as an adaptation to icy Pleistocene weather or the demands of using teeth as tools, and the retracted faces of modern humans are not an adaptation for language, as some anthropologists have proposed.

Instead, random "genetic drift" is the likeliest reason for these skull differences.

Weaver conducted the research with Charles Roseman, an anthropologist at the University of Illinois at Urbana-Champaign, and Chris Stringer, a paleoanthropologist at the Natural History Museum in London.

Source: UC Davis

Related stories:

Britain’s last Neanderthals were more sophisticated than we thought
An archaeological excavation at a site near Pulborough, West Sussex, has thrown remarkable new light on the life of northern Europe’s last Neanderthals. It provides a snapshot of a thriving, developing population – rather than communities on the verge of extinction.

Natural Selection and the Human Skull
New research led by UC Davis anthropologist Tim Weaver adds to the evidence that chance, rather than natural selection, best explains why the skulls of modern humans and ancient Neanderthals evolved differently. The findings may alter how anthropologists think about human evolution.
Neanderthal bearing teeth
An international European research collaboration led by scientists at the Max Planck Institute for Evolutionary Anthropology reports evidence for a rapid developmental pattern in a 100,000 year old Belgian Neanderthal (Homo neanderthalensis).
Ancient DNA reveals that some Neanderthals were redheads
Ancient DNA retrieved from the bones of two Neanderthals suggests that at least some of them had red hair and pale skin, scientists report this week in the journal Science. The international team says that Neanderthals' pigmentation may even have been as varied as that of modern humans, and that at least 1 percent of Neanderthals were likely redheads.
Inconsistencies with Neanderthal genomic DNA sequences
Two recent papers describing the sequencing of Neanderthal nuclear DNA from fossil bone held promise for finally answering this question. However, the two studies came to very different conclusions regarding the ancestral role of Neanderthals.
New evidence on the role of climate in Neanderthal extinction
The mystery of what killed the Neanderthals has moved a step closer to resolution after an international study led by the University of Leeds has ruled out one of the competing theories – catastrophic climate change – as the most likely cause.
Neanderthal Man Was An Innovator, Study Says
Neanderthal man was not as stupid as has been made out says a new study published by a University of Leicester archaeologist.
Gendered division of labor gave modern humans advantage over Neanderthals
Diversified social roles for men, women, and children may have given Homo sapiens an advantage over Neanderthals, says a new study in the December 2006 issue of Current Anthropology. The study argues that division of economic labor by sex and age emerged relatively recently in human evolutionary history and facilitated the spread of modern humans throughout Eurasia.

News discussion:

General Science news