[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: Scientists Claim to Find Mechanism of Natural Selection

Greg, and others:

    If you have a need to discuss the complaints of the anti-evolution
people - especially specific refutations of scientific facts, feel free to
contact me off-list.  I  know some of the objections, and I know some
countering examples.

    For instance, Carbon dating being wrong:  If you apply Carbon dating
techniques to living animals, the results will indicate that the animal died
2000 years ago.  Of course, Carbon dating doen't work on animals as old as
the dinosaurs.  You need to use other techniques.  To some, the fact that
Carbon dating fails at one point, indicates that it is no good.  Gee, a
standard alcohol thermometer will show readings from -34 F to 130 F, but
doen't work outside of the range of.  This doesn't mean that alcohol based
thermometers don't work - only that they don't work outside of a particular

        Allan Edels

-----Original Message-----
From: Greg Claytor <gclaytor@flash.net>
To: Dinosaur List <dinosaur@usc.edu>
Date: Wednesday, November 25, 1998 2:54 PM
Subject: Scientists Claim to Find Mechanism of Natural Selection

>Dinosaur Listees,
>I hope this isn't too off topic. I find this article interesting because
>I've had SO many conversations with folks who think evolution and
>existance of dinosaurs is false science.  They rail on me that carbon
>dating is false, dinosaurs never existed, natural selection is baloney,
>Reprinted from www.foxnews.com
>Scientists Claim to Find
>Mechanism of Natural Selection
>2.00 p.m. ET (1900 GMT) November 25, 1998
>By Amanda Onion
>Nearly 140 years ago, a British naturalist published one of the most
>controversial and influential studies in history. While Charles Darwin?s
>The Origin of the Species was based largely on observation and theory,
>scientists now claim they may have detected a tiny aspect of proof ? at
>the cellular level ? of Darwin?s theory at work.
>"Evolution used to be about arguments. Whoever had the best argument
>won, because there was no way to study it," said David Gardiner, a
>biologist at the University of California at Irvine. "This new study is
>exciting because you can actually go in and see how changes happen."
>Suzanne Rutherford and Susan Lindquist, of the Howard Hughes Medical
>Institute at the University of Chicago, focused on the activity of
>proteins ? substances known as the building blocks of life that are made
>up of strings of amino acids. In their study, which appears in this
>week?s edition of the journal Nature, Rutherford and Lindquist observed
>fruit flies and the role of a specific protein, Hsp90, which exists in
>nearly all creatures from bacteria to humans.
>Hsp90 falls under a larger group of proteins known as "heat-shock"
>proteins. More than 20 years ago, scientists discovered these proteins
>are released when an animal is exposed to high temperatures or other
>stresses such as reduced oxygen or chemical exposure. As other proteins
>start to disassemble under the stress, the heat-shock proteins spring to
>action and keep the other proteins in place. What makes Hsp90
>interesting, however, is it also carries a second, separate role.
>Under normal conditions, Hsp90 also acts as a "molecular chaperone" by
>mediating the correct assembly of new proteins. By guiding the proteins,
>Hsp90 ensures their processes lead to normal development of their
>corresponding traits ? or their so-called expression ? in the body.
>"Think about it as a piece of origami paper," explained Lindquist. "It
>has to be folded just right for it to do what it?s going to do."
>Having dual roles, the scientists found, can be overwhelming for Hsp90.
>When a body falls under stress, Hsp90 attends to the crisis and can
>start to neglect its normal role of ensuring the correct expression of
>new proteins.
>That?s when bizarre things begin to happen.
>"We saw bristles sticking out instead of antennae, we saw eyes that were
>crunched into all different kinds of shapes, we saw wings of all shapes,
>stubby legs, we saw folded-over abdomens," Lindquist said about the
>generations of fruit flies they raised after reducing levels of Hsp90.
>These deformities, Lindquist argues, are evidence of natural selection
>at work. If reducing the role of Hsp90 leads to the unmasking of
>deformities, then, she infers, a wide array of variation must already
>exist within each individual?s genetic code.
>This variation surfaces when the body is under stress and gives rise to
>quirks of nature ? an elongated nose or a sixth toe or a third eye ?
>which either disappear from the species or persist if they prove
>favorable to survival.
>"The general impression among biologists has been that the genes that
>control major pathways ? like for a leg or a wing ? are pretty much the
>same," Lindquist said. "But this suggests there is a lot more variation
>in the genome than we thought."
>The question is, could Hsp90 act the same way in humans as it did in the
>fruit flies? Could environmental hazards unleash a string of deformities
>among humans, perhaps even leading to a different form of ourselves?
>One clue may lie in another, more sensitive creature: the frog. Over the
>past few decades, biologists have noted a marked decrease among frog
>populations as well as a nearly 15-fold rise in the number of
>deformities appearing in frog species. Scientists have traced the cause
>to an increase of polluted waters but have been uncertain exactly how
>the polluted waters affect the frogs.
>According to David Gardiner, a biologist who specializes in frog
>deformities, the problem does not appear to lie within the frogs?
>genetic codes, but in agents responsible for gene expression, such as
>"What we?re seeing in the frogs is a developmental disruption," Gardiner
>said. "I have a feeling there is a relationship between what?s happening
>[to the frogs] and this study, but it?s unclear what the relationship
>might be."
>In their next work, Lindquist and Rutherford plan to explore that
>question further and try to determine if Hsp90 or a similar protein
>could be playing a role in the increasing number of deformities among
>Whatever answers the scientists find in the frog may carry implications
>for our own biological future. The thin-skinned nature of the slippery
>amphibian has earned it the distinction of being the "canary in the coal
>mine" of impending environmental doom.
>The scientists also hope their ongoing work may offer further evidence
>to bolster the bearded naturalist Darwin's claims when he argued in 1859
>that animals are constantly evolving.
>"I think people tend to think that evolution happened and we?re done,
>we?re it. And of course that?s not the case at all," said Gardiner.
>"It?s an ongoing process. Through these studies we can see inside to the
>nuts and bolts of the body and watch evolution take place."