[Marxism] Multiple solutions in evolution
rholt at planeteria.net
Wed Aug 24 21:40:01 MDT 2005
For those interested in evolution and/or “intelligent design” I
recommend an excellent article by Henry Gee, part of which is reproduced
below. Understanding the rather anarchic nature of nature is important.
Published online: 07 July 2004; | doi:10.1038/news040705-1
muse at nature.com:
The tyranny of design
by Henry Gee
We are accustomed to thinking of ourselves as peaks of perfection, and
the arrangements of more "primitive" creatures as similar to our own,
only cruder. It's a nice idea. Until along comes the sea lamprey to
challenge our preconceptions.
Researchers have found that the lamprey (Petromyzon marinus) has a has a
sophisticated system of adaptive immunity, that is entirely different to
our own. Many organisms have a kind of natural immunity, but the
adaptive immunity of mammals was supposed to be something special. By
dint of a kind of controlled chaos, specialized parts of our genomes
rearrange themselves to produce antibodies, custom-built proteins that
are then selected to target any kind of foreign molecule the world can
throw at us.
One of the great mysteries of immunology is how and when this remarkable
system originated. For many years, immunologists looked for its
beginnings in lampreys, sucker-mouthed creatures that represent the
earliest flourish of vertebrate evolution more than 500 million years
ago. Lacking jaws and paired fins, lampreys are almost as primitive as a
vertebrate can get. They seem to have adaptive immunity, but scientists
haven't found even a glimmer of any antibodies.
The discovery, reported by Max Cooper and colleagues in Nature this
week, that lampreys have developed a perfectly respectable adaptive
immune system all by themselves shows that the problem lies not with
evolution itself but more with the way we think about it. Alas, we
humans do not represent the pinnacle of design to which all other
species aspire. Collins' work shows us, once again, that evolution
experiments with various solutions to life's problems, only some of
which stay the course. There never was only one system of adaptive
immunity: thanks to the lamprey we now know that there were at least
two, and possibly many more, now extinct, or remaining to be discovered.
There never was only one solution to adaptive immunity: thanks to the
lamprey we now know there were at least two.
The fact that the work seems so surprising exposes another, more
dangerous conceit that scientists are prone to. Dangerous, because it
leaves science wide open to the temptations of so-called 'Intelligent
Design'. Advocates of this view object to evolution by invoking what
Richard Dawkins has called the 'Argument from Incredulity' – that is, if
I don't believe that something is possible, it cannot happen.
Philosopher William Paley in his Natural Theology famously used this
argument when he compared the delicate designs of nature with a pocket
watch. Pocket watches are not made spontaneously, so if the existence of
a functioning, integrated watch implies a watchmaker, then the same must
surely apply to a living creature.
More than a century later, proponents of Intelligent Design use the same
reasoning when they marvel at the intricate design of, say, a bacterial
flagellar motor. How can one ever give credence to the view that the
sophisticated mechanism of the flagellar motor could have evolved to
such precision without a guiding hand, when the tiniest of changes to
its apparently irreducible complexity might render it useless?
I was discussing the problem with two polymathic friends of mine,
reproductive biologist Jack Cohen and mathematician Ian Stewart,
co-authors of Figments of Reality, Evolving the Alien and The Science of
Discworld. They are working on their next book, Appearance of Design (to
be published by Penguin next year) and Cohen sent me a draft chapter
containing a devastating response to the challenge of Intelligent
Design. It arrived on my desk at about the time that the work on the
lamprey immune system was making waves in the Nature office, so it
struck a particular chord with me.
Cohen argues that the fallacy in the Intelligent-Design argument about
the flagellar motor (or any other system), is that proponents present
the motor we see as The Motor, the exemplar, the only one possible, and,
what's more the best possible, surely optimized by a Designing Hand. But
when Cohen searched the literature, he found that a wide variety of
flagellar motors have been described, each arranged in its own way, each
its own solution to effective rotary motion in the microworld. There is
no such thing as The Motor, no Platonic perfection enforced on bacteria
by Divine fiat. Instead we see ad hoc solutions that are not perfect,
but idiosyncratic and eclectic – just what you would expect if evolution
were working on its own, without a Designer.
[complete at http://www.nature.com/news/2004/040705/full/040705-1.html
And it’s free, I hope. If not, let me know
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