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MSNBC.com
Human evolution at the crossroads
Genetics, cybernetics complicate forecast for species
By Alan Boyle
Science editor
Updated: 6:00 p.m. ET May 2, 2005
Scientists are fond of running the evolutionary clock backward, using DNA analysis and the fossil record to figure out when our ancestors stood erect and split off from the rest of the primate evolutionary tree.
But the clock is running forward as well. So where are humans headed?
Evolutionary biologist Richard Dawkins says it's the question he's most often asked, and "a question that any prudent evolutionist will evade." But the question is being raised even more frequently as researchers study our past and contemplate our future.
Paleontologists say that anatomically modern humans may have at one time shared the Earth with as many as three other closely related types — Neanderthals, Homo erectus and the dwarf hominids whose remains were discovered last year in Indonesia.
Does evolutionary theory allow for circumstances in which "spin-off" human species could develop again?
Some think the rapid rise of genetic modification could be just such a circumstance. Others believe we could blend ourselves with machines in unprecedented ways — turning natural-born humans into an endangered species.
Present-day fact, not science fiction
Such ideas may sound like little more than science-fiction plot lines. But trend-watchers point out that we're already wrestling with real-world aspects of future human development, ranging from stem-cell research to the implantation of biocompatible computer chips. The debates are likely to become increasingly divisive once all the scientific implications sink in.
"These issues touch upon religion, upon politics, upon values," said Gregory Stock, director of the Program on Medicine, Technology and Society at the University of California at Los Angeles. "This is about our vision of the future, essentially, and we'll never completely agree about those things."
The problem is, scientists can't predict with precision how our species will adapt to changes over the next millennium, let alone the next million years. That's why Dawkins believes it's imprudent to make a prediction in the first place.
Others see it differently: In the book "Future Evolution," University of Washington paleontologist Peter Ward argues that we are making ourselves virtually extinction-proof by bending Earth's flora and fauna to our will. And assuming that the human species will be hanging around for at least another 500 million years, Ward and others believe there are a few most likely scenarios for the future, based on a reading of past evolutionary episodes and current trends.
Where are humans headed? Here's an imprudent assessment of five possible paths, ranging from homogenized humans to alien-looking hybrids bred for interstellar travel.
Unihumans: Will we all be assimilated?
Biologists say that different populations of a species have to be isolated from each other in order for those populations to diverge into separate species. That's the process that gave rise to 13 different species of "Darwin's Finches" in the Galapagos Islands. But what if the human species is so widespread there's no longer any opening for divergence?
Evolution is still at work. But instead of diverging, our gene pool has been converging for tens of thousands of years — and Stuart Pimm, an expert on biodiversity at Duke University, says that trend may well be accelerating.
"The big thing that people overlook when speculating about human evolution is that the raw matter for evolution is variation," he said. "We are going to lose that variability very quickly, and the reason is not quite a genetic argument, but it's close. At the moment we humans speak something on the order of 6,500 languages. If we look at the number of languages we will likely pass on to our children, that number is 600."
Cultural diversity, as measured by linguistic diversity, is fading as human society becomes more interconnected globally, Pimm argued. "I do think that we are going to become much more homogeneous," he said.
Ken Miller, an evolutionary biologist at Brown University, agreed: "We have become a kind of animal monoculture."
Is that such a bad thing? A global culture of Unihumans could seem heavenly if we figure out how to achieve long-term political and economic stability and curb population growth. That may require the development of a more "domesticated" society — one in which our rough genetic edges are smoothed out.
But like other monocultures, our species could be more susceptible to quick-spreading diseases, as last year's bird flu epidemic illustrated.
"The genetic variability that we have protects us against suffering from massive harm when some bug comes along," Pimm said. "This idea of breeding the super-race, like breeding the super-race of corn or rice or whatever — the long-term consequences of that could be quite scary."
nastavak na sledecem linku (tekst je dosta dugacak):
http://www.msnbc.msn.com/id/7103668/
(izvinjavam se sto nemam verziju na nasem, bilo bi izvodljivo prevesti ako treba. mislim da je tema vrlo zanimljiva)
Dopuna: 19 Jul 2007 16:43
dodajem odlican site na ovu temu: http://www.human-evolution.org/
i samo jedan side comment - znam da je gore navedeni clanak iz 2005. godine, ali je daleeeko od toga da je zastareo (a i te dve godine i koji mesec su jedan blink od blinka iz gledista stotina hiljada godina perspektive)
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