Monday, March 12, 2007

DNA and brains

As Naomi from GifS and Martian Anthropolgist said when she emailed me this one, “too wonderful to miss out on–especially as it shows the flexibility of science and evolutionary theories!” From Newsweek: Beyond Bones & Stones

excerpt: The science of human evolution is undergoing its own revolution. Although we tend to see the march of species down through time as a single-file parade, with descendant succeeding ancestor in a neat line, the emerging science shows that the story of our species is far more complicated than Biblical literalists would have it—but also more complex than secular science suspected.[my emphasis] By analyzing the DNA of today’s humans as well as chimps and other species (even lice), scientists are zeroing in on turning points in evolution, such as when and how language and speech developed, and when our ancestors left Africa. DNA can even reveal how many pilgrims made that trek. At the new Hall of Human Origins at the American Museum of Natural History in New York, DNA gets equal billing with fossils. And by comparing the impressions that brains left on the inside of skulls, “paleoneurology” is documenting when structures that power the human mind arose, shedding light on how our ancestors lived and thought. Whether or not you believe the hand of God was guiding these changes, the discoveries are overturning longstanding ideas about how we became human.

Not that fossils are passé. new discoveries are pruning and reshaping humankind’s family tree as radically as bonsai. The neat traditional model in which one species gave rise to another like Biblical “begats” has been replaced by a profusion of branches, representing species that lived at the same time as our direct ancestors but whose lines died out. It’s like discovering that your great-great-grandfather was not an only child as you’d thought, but had a number of siblings who, for unknown reasons, left no descendants. New research also shows that “progress” and “human evolution” are only occasional partners. More than once in human prehistory, evolution created a modern trait such as a face without jutting, apelike brows and jaws, only to let it go extinct, before trying again a few million years later. Our species’ travels through time proceeded in fits and starts, with long periods when “nothing much happened,” punctuated by bursts of dizzying change, says paleontologist Ian Tattersall, co-curator of the American Museum’s new hall.

Read the entire article here (also link above). It’s long, but well worth your time. Let me know what you think...especially those biology and archaeology experts out there.

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