On Wed, 02 Oct 1996 20:24:10 -0400 (EDT), Loren Haarsma wrote:
>LH>Here's something which appeared in another science-and-faith
>discussion group today. I thought y'all would like to see it. I
>got the author's permission to post it here. I can forward any
>replies to her, or you can just cc to her directly (address at the
>bottom).
>AF>I just got in Behe's book, and will read it as soon as I
>can...Before reading it though, I thought I would share one example
>that Behe may or may not discuss.
AFAIK Mike Behe does not discuss the "citric acid cycle" (aka.
known as the Krebs Cycle):
"The Krebs cycle...is named for Hans Krebs, a British
scientist who received the Nobel Prize for his part in determining
these reactions in the 1930s. This cyclical series of reactions
begins with a six-carbon organic compound called citric acid
(citrate); for this reason the series is also known as the citric
acid cycle. " (Mader S.S., "Biology", Wm. C. Brown: Dubeque IA,
Third Edition, 1990, p132)
but no doubt as a Professor of Biochemistry he would be well aware of
it.
>AF>There is an extremely important metabolic pathway called the
>citric acid cycle which in us and in almost all organisms is used to
>burn fuels (both fats and sugars) and to make new building blocks of
>several kinds. The pathway is a cycle: there are enzymes that pass
>the changed molecules on to the next one and the path comes back to
>itself to repeat. The path is useful because you can feed in
>four-carbon molecules and get out two two-carbon molecules and some
>energy (among other ways to use it).
"How many are your works, O LORD! In wisdom you made them all" (Ps
104:24).
>AF>Now, blue green algae (which are very ancient - fossils dating
>back 3.5 billion years) don't have this cycle, and they can't grow
>on sugar for that reason; they have to make all their own fuel and
>they don't grow in the dark. How come? Where did the citric acid
>cycle come from? Well, it turns out that the blue green algae do
>have all of the enzymes of the cycle, except for one. What use is
>this "incomplete" cycle? It turns out that if you look at the
>"broken" cycle with that question in mind, you notice something very
>interesting: each half of the cycle is useful for something in its
>own right. The "right" half of the cycle is good for making amino
>acids and the "left" half of the cycle makes compounds that are
>needed for making chlorophyll and other energy related molecules.
>So, even without the enzyme that closes the cycle, all the other
>enzymes are useful.
This is powerful evidence that an Intelligent Designer prepared these
two "incomplete" cycles in advance, something that Neo-Darwinist,
"blind watchmaker" evolution could never do:
"Favorable changes are one thing; changes that will be favorable,
another. If the mechanism of Darwinian evolution is restricted to
changes that are favorable at the time they are selected, I see no
reason to suppose that it could produce any fancy structures
whatsoever. If the mechanism is permitted to incorporate changes
that are neutral at the time of selection, but that will be favorable
some time in the future, I see no reason to consider the process
Darwinian. " (Berlinski D., "Denying Darwin: David Belinski and
Critics", Commentary, September 1996, p25)
>AF>Then how did the cycle come about? It turns out that the enzyme
>that closes the cycle is very similar to the enzyme that feeds fuels
>into the pathway. It would only have taken a few amino acid changes
>to change one into the other, so the parsimonious guess is that some
>organism had a mutation like that, and now it could grow in the dark
>or by using other fuels. Since that would be very useful, it is
>easy to see how it spread.
Perhaps. The hard part was preparing the two halves ready for their
future, combined role. But, I suspect this is a vast over-
simplification in any event. If this was so "easy", why does it not
happen time and time again?
>AF>My point is this: sometimes the evolutionary roots of things
>aren't visible unless you know a lot of organisms and look to see
>uses that aren't the ones that are taught in the textbooks.
This is assuming without warrant that evidence of common ancestry is
necessarily "evolutionary". An Intelligent Designer could equally
have: a) prepared the two parts of the Krebs cycle, and b) at the
planned time brought the two together.
AF>Especially in metabolism there is a great deal known that just
>plain doesn't fit into the texts. When I read Behe I will be
>looking to see how far back he looks for these kinds of connections
>and if he doesn't I have people here that I can ask. It looks
>interesting, though.
Behe does not deny these "connections". But he points out that the
usual Darwinist "just-so" stories fail to get to grips with the
details. Here he summarises his thesis:
"Indeed. just as the pleasing shape of a jetliner belies the complexity
of its internal organization, so the complexity of life mushrooms as
one gets closer to its foundation. The shape of the eye, which Darwin
tried to explain, pales in comparison with the interactions of
rhodopsin, transducin, arrestin, rhodopsin kinase, and other proteins
in the visual cascade. Explaining how the swimming behavior of a
whale might be produced gradually (if anybody ever succeeded in
doing this) would be a walk in the park compared to explaining the
bacterial swimming system-the flagellum, which requires more than
40 gene products to function. Most people consider Darwinism,
whatever its faults, to be science. Yet in an interesting way they are
wrong-at least in my area of biochemistry, the study of life's
foundation. Scientific results get reported in science journals, like
Nature, the Journal of Biological Chemistry, and so forth. But if you
search the science journals, as I have done, for detailed explanations
of how particular, complex biochemical systems (such as, say, the
bloodclotting system or intracellular transport) were produced, you
come up completely empty handed. Astonishingly, science's own
journals contain no explanations. Since science is found in science
journals and Darwinian explanations are absent, Darwinism is not
science." (Behe M.J., "Denying Darwin: David Belinski and Critics",
Commentary, September 1996, pp21-22)
God bless.
Steve
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