[Paleopsych] MSNBC: Human evolution at the crossroads
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Thu May 5 14:55:40 UTC 2005
Human evolution at the crossroads
Genetics, cybernetics complicate forecast for species
By Alan Boyle
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
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
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
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
"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
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."
Environmental pressures wouldn't stop
Even a Unihuman culture would have to cope with evolutionary pressures
from the environment, the University of Washington's Peter Ward said.
Some environmentalists say toxins that work like estrogens are already
having an effect: Such agents, found in pesticides and industrial PCBs,
have been linked to earlier puberty for women, increased incidence of
breast cancer and lower sperm counts for men.
"One of the great frontiers is going to be trying to keep humans alive
in a much more toxic world," he observed from his Seattle office. "The
whales of Puget Sound are the most toxic whales on Earth. Puget Sound is
just a huge cesspool. Well, imagine if that goes global."
Global epidemics or dramatic environmental changes represent just two of
the scenarios that could cause a Unihuman society to crack, putting
natural selection - or perhaps not-so-natural selection - back into the
evolutionary game. Then what?
Survivalistians: Coping with doomsday
Surviving doomsday is a story as old as Noah's Ark, and as new as the
post-bioapocalypse movie "28 Days After."
Catastrophes ranging from super-floods to plagues to nuclear war to
asteroid strikes erase civilization as we know it, leaving remnants of
humanity who go their own evolutionary ways.
The classic Darwinian version of the story may well be H.G. Wells' "The
Time Machine," in which humanity splits off into two species: the
ruthless, underground Morlock and the effete, surface-dwelling Eloi.
At least for modern-day humans, the forces that lead to species
spin-offs have been largely held in abeyance: Populations are
increasingly in contact with each other, leading to greater gene-mixing.
Humans are no longer threatened by predators their own size, and
medicine cancels out inherited infirmities ranging from hemophilia to
"We are helping genes that would have dropped out of the gene pool,"
paleontologist Peter Ward observed.
But in Wells' tale and other science-fiction stories, a
civilization-shattering catastrophe serves to divide humanity into
separate populations, vulnerable once again to selection pressures. For
example, people who had more genetic resistance to viral disease would
be more likely to pass on that advantage to their descendants.
If different populations develop in isolation over many thousands of
generations, it's conceivable that separate species would emerge. For
example, that virus-resistant strain of post-humans might eventually
thrive in the wake of a global bioterror crisis, while less hardy humans
would find themselves quarantined in the world's safe havens.
Patterns in the spread of the virus that causes AIDS may hint at
earlier, less catastrophic episodes of natural selection, said Stuart
Pimm, a conservation biologist at Duke University: "There are pockets of
people who don't seem to become HIV-positive, even though they have a
lot of exposure to the virus - and that may be because their ancestors
survived the plague 500 years ago."
Evolution, or devolution?
If the catastrophe ever came, could humanity recover? In science
fiction, that's an intriguingly open question. For example, Stephen
Baxter's novel "Evolution" foresees an environmental-military meltdown
so severe that, over the course of 30 million years, humans devolve into
separate species of eyeless mole-men, neo-apes and elephant-people
herded by their super-rodent masters.
Even Ward gives himself a little speculative leeway in his book "Future
Evolution," where a time-traveling human meets his doom 10 million years
from now at the hands - or in this case, the talons - of a flock of
intelligent killer crows. But Ward finds it hard to believe that even a
global catastrophe would keep human populations isolated long enough for
our species to split apart.
"Unless we totally forget how to build a boat, we can quickly come
back," Ward said.
Even in the event of a post-human split-off, evolutionary theory
dictates that one species would eventually subjugate, assimilate or
eliminate their competitors for the top job in the global ecosystem.
Just ask the Neanderthals.
"If you have two species competing over the same ecological niche, it
ends badly for one of them, historically," said Joel Garreau, the author
of the forthcoming book "Radical Evolution."
The only reason chimpanzees still exist today is that they "had the
brains to stay up in the trees and not come down into the open
grasslands," he noted.
"You have this optimistic view that you're not going to see speciation
(among humans), and I desperately hope that's right," Garreau said. "But
that's not the only scenario."
Numans: Rise of the superhumans
We've already seen the future of enhanced humans, and his name is Barry
The controversy surrounding the San Francisco Giants slugger, and
whether steroids played a role in the bulked-up look that he and other
baseball players have taken on, is only a foretaste of what's coming as
scientists find new genetic and pharmacological ways to improve
Developments in the field are coming so quickly that social commentator
Joel Garreau argues that they represent a new form of evolution. This
radical kind of evolution moves much more quickly than biological
evolution, which can take millions of years, or even cultural evolution,
which works on a scale of hundreds or thousands of years.
How long before this new wave of evolution spawns a new kind of human?
"Try 20 years," Garreau told MSNBC.com.
In his latest book, "Radical Evolution," Garreau reels off a litany of
high-tech enhancements, ranging from steroid Supermen, to
camera-equipped flying drones, to pills that keep soldiers going without
sleep or food for days.
"If you look at the superheroes of the '30s and the '40s, just about all
of the technologies they had exist today," he said.
Three kinds of humans
Such enhancements are appearing first on the athletic field and the
battlefield, Garreau said, but eventually they'll make their way to the
collegiate scene, the office scene and even the dating scene.
"You're talking about three different kinds of humans: the enhanced, the
naturals and the rest," Garreau said. "The enhanced are defined as those
who have the money and enthusiasm to make themselves live longer, be
smarter, look sexier. That's what you're competing against."
In Garreau's view of the world, the naturals will be those who eschew
enhancements for higher reasons, just as vegetarians forgo meat and
fundamentalists forgo what they see as illicit pleasures. Then there's
all the rest of us, who don't get enhanced only because they can't.
"They loathe and despise the people who do, and they also envy them,"
Scientists acknowledge that some of the medical enhancements on the
horizon could engender a "have vs. have not" attitude.
"But I could be a smart ass and ask how that's different from what we
have now," said Brown University's Ken Miller.
Medical advances as equalizers
Miller went on to point out that in the past, "advances in medical
science have actually been great levelers of social equality." For
example, age-old scourges such as smallpox and polio have been
eradicated, thanks to public health efforts in poorer as well as richer
countries. That trend is likely to continue as scientists learn more
about the genetic roots of disease, he said.
"In terms of making genetic modifications to ourselves, it's much more
likely we'll start to tinker with genes for disease susceptibility. ...
Maybe there would be a long-term health project to breed HIV-resistant
people," he said.
When it comes to discussing ways to enhance humans, rather than simply
make up for disabilities, the traits targeted most often are longevity
and memory. Scientists have already found ways to enhance those traits
Imagine improvements that could keep you in peak working condition past
the age of 100. Those are the sorts of enhancements you might want to
pass on to your descendants - and that could set the stage for
reproductive isolation and an eventual species split-off.
"In that scenario, why would you want your kid to marry somebody who
would not pass on the genes that allowed your grandchildren to have
longevity, too?" the University of Washington's Peter Ward asked.
But that would require crossing yet another technological and ethical
Instant superhumans - or monsters?
To date, genetic medicine has focused on therapies that work on only one
person at a time. The effects of those therapies aren't carried on to
future generations. For example, if you take muscle-enhancing drugs, or
even undergo gene therapy for bigger muscles, that doesn't mean your
children will have similarly big muscles.
In order to make an enhancement inheritable, you'd have to have new code
spliced into your germline stem cells - creating an ethical controversy
of transcendent proportions.
Tinkering with the germline could conceivably produce a superhuman
species in a single generation - but could also conceivably create a
race of monsters. "It is totally unpredictable," Ward said. "It's a lot
easier to understand evolutionary happenstance."
Even then, there are genetic traits that are far more difficult to
produce than big muscles or even super-longevity - for instance, the
very trait that defines us as humans.
"It's very, very clear that intelligence is a pretty subtle thing, and
it's clear that we don't have a single gene that turns it on or off,"
When it comes to intelligence, some scientists say, the most likely
route to our future enhancement - and perhaps our future competition as
well - just might come from our own machines.
Cyborgs: Merging with the machines
Will intelligent machines be assimilated, or will humans be eliminated?
Until a few years ago, that question was addressed only in
science-fiction plot lines, but today the rapid pace of cybernetic
change has led some experts to worry that artificial intelligence may
outpace Homo sapiens' natural smarts.
The pace of change is often stated in terms of Moore's Law, which says
that the number of transistors packed into a square inch should double
every 18 months. "Moore's Law is now on its 30th doubling. We have never
seen that sort of exponential increase before in human history," said
Joel Garreau, author of the book "Radical Evolution."
In some fields, artificial intelligence has already bested humans - with
Deep Blue's 1997 victory over world chess champion Garry Kasparov
providing a vivid example.
Three years later, computer scientist Bill Joy argued in an influential
Wired magazine essay that we would soon face challenges from intelligent
machines as well as from other technologies ranging from weapons of mass
destruction to self-replicating nanoscale "gray goo."
Joy speculated that a truly intelligent robot may arise by the year
2030. "And once an intelligent robot exists, it is only a small step to
a robot species - to an intelligent robot that can make evolved copies
of itself," he wrote.
Assimilating the robots
To others, it seems more likely that we could become part-robot
ourselves: We're already making machines that can be assimilated -
including prosthetic limbs, mechanical hearts, cochlear implants and
artificial retinas. Why couldn't brain augmentation be added to the
"The usual suggestions are that we'll design improvements to ourselves,"
said Seth Shostak, senior astronomer at the SETI Institute. "We'll put
additional chips in our head, and we won't get lost, and we'll be able
to do all those math problems that used to befuddle us."
Shostak, who writes about the possibilities for cybernetic intelligence
in his book "Sharing the Universe," thinks that's likely to be a
transitional step at best.
"My usual response is that, well, you can improve horses by putting
four-cylinder engines in them. But eventually you can do without the
horse part," he said. "These hybrids just don't strike me as having a
tremendous advantage. It just means the machines aren't good enough."
Back to biology
University of Washington paleontologist Peter Ward also believes
human-machine hybrids aren't a long-term option, but for different
"When you talk to people in the know, they think cybernetics will become
biology," he said. "So you're right back to biology, and the easiest way
to make changes is by manipulating genomes."
It's hard to imagine that robots would ever be given enough free rein to
challenge human dominance, but even if they did break free, Shostak has
no fear of a "Terminator"-style battle for the planet.
"I've got a couple of goldfish, and I don't wake up in the morning and
say, 'I'm gonna kill these guys.' ... I just leave 'em alone," Shostak
said. "I suspect the machines would very quickly get to a level where we
were kind of irrelevant, so I don't fear them. But it does mean that
we're no longer No. 1 on the planet, and we've never had that happen
Astrans: Turning into an alien race
If humans survive long enough, there's one sure way to grow new branches
on our evolutionary family tree: by spreading out to other planets.
Habitable worlds beyond Earth could be a 23rd century analog to the
Galapagos Islands, Charles Darwin's evolutionary laboratory: just barely
close enough for travelers to get to, but far enough away that there'd
be little gene-mixing with the parent species.
"If we get off to the stars, then yes, we will have speciation," said
University of Washington paleontologist Peter Ward. "But can we ever get
off the Earth?"
Currently, the closest star system thought to have a planet is Epsilon
Eridani, 10.5 light-years away. Even if spaceships could travel at 1
percent the speed of light - an incredible 6.7 million mph - it would
take more than a millennium to get there.
Even Mars might be far enough: If humans established a permanent
settlement there, the radically different living conditions would change
the evolutionary equation. For example, those who are born and raised in
one-third of Earth's gravity could never feel at home on the old "home
planet." It wouldn't take long for the new Martians to become a breed
As for distant stars, the SETI Institute's Seth Shostak has already been
thinking through the possibilities:
# Build a big ark: Build a spaceship big enough to carry an entire
civilization to the destination star system. The problem is, that
environment might be just too unnatural for natural humans. "If you talk
to the sociologists, they'll say that it will not work. ... You'll be
lucky if anybody's still alive after the third generation," Shostak
# Go to warp speed: Somehow we discover a wormhole or find a way to
travel at relativistic speeds. "That sounds OK, except for the fact that
nobody knows how to do it," Shostak said.
# Enter the Astrans: Humans are genetically engineered to tolerate ultra
long-term hibernation aboard robotic ships. Once the ship reaches its
destination, these "Astrans" are awakened to start the work of settling
a new world. "That's one possibility," Shostak said.
The ultimate approach would be to send the instructions for making
humans rather than the humans themselves, Shostak said.
"We're not going to put anything in a rocket, we're just going to beam
ourselves to the stars," he explained. "The only trouble is, if there's
nobody on the other end to put you back together, there's no point."
So are we back to square one? Not necessarily, Shostak said. Setting up
the receivers on other stars is no job for a human, "but the machines
could make it work."
In fact, if any other society is significantly further along than ours,
such a network might be up and running by now. "The machines really
could develop large tracts of galactic real estate, whereas it's really
hard for biology to travel," Shostak said.
It all seems inconceivable, but if humans really are extinction-proof -
if they manage to survive global catastrophes, genetic upheavals and
cybernetic challenges - who's to say what will be inconceivable millions
of years from now? Two intelligent species, human and machine, just
might work together to spread life through the universe.
"If you were sufficiently motivated," Shostak said, "you could in fact
keep it going forever."
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