I recently obtained Peter Hochachka's book, "Muscles as Molecular
and Metabolic Machines." This book is simply a review of muscle cell
physiology from the molecular machine perspective. In my opinion, it provides
an excellent example of the way ID can be used to conduct and
present scientific findings.
Hochachka begins by asking a truly insightful question:
"The working parts of the complete muscle machine are proteins-
contractile proteins, structural proteins, enzyme proteins, channels,
pumps, transporters, and so forth - and a conservative count indicates
well over 100 such machine parts in any given muscle. Since most
occur as cell-specific isoforms, the random assortment of these machine
parts or protein isoforms in theory could generate an astronomical
number of muscle machines (fiber types). But this does not occur
and the question is, why not?"
Note Hochachka's angle on this question:
"To attack this problem, I complemented the reductionist approach
with an integrationist/adaptational one that again extended from genes
to proteins, and this is where the fun really began. Analysis of how
these components work led to the realization that all levels of the
muscle machine - at information transfer to the contractile elements,
at the energy consuming contractile elements per se, at the energy
consuming relaxation processes, and at the energy regeneration
pathways - the system is being driven more and more by highly
efficient interactions between muscle components, less and less
by diffusion-based processes proposed to be dominant in traditional
paradigms."
The "intergrationist/adaptational" approach is simply the IC approach.
where it is realized that for function to occur, many independent
parts must be integrated in highly specific ways. What Hochachka
finds is that muscle is more machine-like than anyone may have
suspected. The process of diffusion plays a secondary role while
the primary control mechanisms employed involve physical
interactions between parts that channel substrates directly to each
other and also mask or unmask the catalytic potentials of various
components. In the future, I'll provide some examples.
The bottom-line is that the Paleyian view of life is vindicated with
muscles. The internal workings of a muscle cell fit very well with
the features of the watch that led Paley to infer design.
The machine paradigm also solves Hochachka's question:
"the evidence suggests that the more highly specialized the muscle
type, the further one moves from the extreme of infinite assortment
possibilities and infinite number of machine varieties. In super-specialized
cases, typically only one fiber type is found, implying that instead of
random assortment of isoform or machine parts, only specific and
often unqiue combinations can work in acceptable fashion."
In other words, since function depends on well-matched parts, only
a small set of parts can carry out any specific function.
Hochachka drives this point home with a simple example:
"We suggest that the isoform design of the overall system is one reason
why the realized number of muscle types is only a minute fraction of
the maximum number theoretically possible. Just as the drive shaft
of a sports car would not do in a cement truck, troponin c isoforms in
fast muscles may not be suitable for slow muscles; fast muscle Ca ATPase
may be debilitating to slow muscle, while slow muscle presynaptic
Ca channels would simply not work well enough in fast muscle, and
so forth."
Hochachka ends his book with the following paragraph:
"The analogy with working machines seems entirely appropriate. It is
biological machinery we are talking about, but machinery, nevertheless.
As in any man-made counter-part, fine-tuning (of isoform content and
composition) is of course possible and may be desirable, but large-scale
change in any one component of the overall system may well be expected
to reverberate throughout the whole system. That is why the effects of
any one of the host of modest mutations (causing single but large magnititude
change in any one component of the system) are, in machinery analogy, like
a spanner in the works. Misplaced spanners are intolerable in man-made
and muscle machines."
Of course, what is disappointing is that Hochachka doesn't see the
implications.
Despite treating muscles as machines and finding how this illuminates and
solves problems, despite writing sections entitled, "Design Criteria for ‰¥Ï",
despite recognizing that one change here is useless or detrimental without
several other changes over there, Hochachka is willing to attribute the
design to natural selection. No where in his book does he explain how
natural selection built slow and fast muscles when intermediate forms and
combinations don't work. No where does he even explain when muscle
evolved, from what did it evolve, and how it evolved.
This book is an excellent guide for showing not only the utility of
the design approach, but how natural selection and evolution are
added as after-the-fact considerations, incapable of guiding the
research themselves.
One final quote:
"One of the unexpected spinoffs of writing this book was the recognition,
which all scientists probably consider from time to time, of how powerful
are the constraining forces of prevailing paradigms in shaping thinking
and research in science. When first introduced, new theories expand
insight and are intellectually liberating, but the exact opposite can occur,
especially in problem areas that are relatively intractable for prolonged
periods of time (well illustrated in the field of regulation of muscle
energetics). In such cases, prevailing paradigms become prevailing
dogmas which tend to stifle creativity and to imprison the imaginative
mind."
Mike
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