|
|
  
Probe Ministries
The Five Crises in Evolutionary Theory
Dr. Ray Bohlin
The Case of the Missing Mechanism
The growing crisis in Darwinian theory is becoming more apparent
all the time. The work of creationists and other non-Darwinians is
growing and finding a more receptive ear than ever before. In this
discussion I want to elaborate on what I believe are the five
critical areas where Darwinism and evolutionary theory in general
are failing. They are:
- The unsubstantiation of a Darwinian mechanism of evolution
- The total failure of origin of life studies to produce
a workable model
- The inability of evolutionary
mechanism to explain the origin of complex adaptations
- The bankruptcy of the blind watchmaker hypothesis
- The biological evidence that the rule in nature is
morphological stability over time and not constant change.
Much of the reason for evolution's privileged status has been due
to confusion over just what people mean when they use the word
evolution. Evolution is a slippery term. If evolution simply means
"change over time," this is non-controversial. Peppered moths,
Hawaiian drosophila fruit flies, and even Galapagos finches are
clear examples of change over time. If you say that this form of
evolution is a fact, well, so be it. But many scientists
extrapolate beyond this meaning. Because "change over time" is a
fact, the argument goes, it is also a fact that moths, fruit flies,
and finches all evolved from a remote common ancestor. But this
begs the question.
The real question, however, is where do moths, flies, and finches
come from in the first place? Common examples of natural selection
acting on present genetic variation do not tell us how we have come
to have horses, wasps, and woodpeckers, and the enormous varieties
of living animals. Evolutionists will tell you that this is where
mutations enter the picture. But mutations do not improve the
scenario either. In speaking of all the mutation work done with
bacteria over several decades, the great French zoologist and
evolutionist Pierre-Paul Grasse' said:
What is the use of their unceasing mutations if they do
not change? In sum, the mutations of bacteria and viruses are
merely hereditary fluctuations around a median position; a swing to
the right, a swing to the left, but no final evolutionary effect.
When I speak of evolution or Darwinism, it is the origin of new
biological forms, new adaptive structures, morphological and
biochemical novelties that I am referring to. This is precisely
what has not yet been explained. When people question the popular
explanations of the origin of complex adaptations such as the
vertebrate limb, or sexual reproduction, or the tongue of the
woodpecker, or the reptilian hard-shelled egg, they are usually
given a litany of reasons why these structures are beneficial to
the organisms. More precisely, the selective advantage of these
structures is offered as the reason they evolved. But this begs the
question again. It is not sufficient for an evolutionist to explain
the function of a particular structure. What is necessary is to
explain the mechanistic origin of these structures!
Natural selection does explain how organisms adapt to minor changes
in their environment. Natural selection allows organisms to do what
God commanded them to do. That is to be fruitful and multiply.
Natural selection does not, however, explain the crucial question
of how complex adaptations arose in the first place.
The Origin of Life
We have been led to believe that it is not to difficult to conceive
of a mechanism whereby organic molecules can be manufactured in a
primitive earth and organize themselves into a living, replicating
cell. In fact, the ease by which this can (allegedly) happen is the
foundation for the popular belief that there are numerous planets
in the universe which contain life. Nothing could be further from
the truth.
Early experiments suggested that it was relatively simple to
produce some of the building blocks of life such as amino acids,
the components of proteins. However, the euphoria of the Miller-
Urey experiment of 1953 has given way to a paradigm crisis of 1993
in origin of life research. The wishful, yet workable atmosphere of
ammonia, hydrogen, methane, and water vapor has been replaced by
the more realistic, but stingy atmosphere of nitrogen, carbon
dioxide, carbon monoxide, hydrogen sulfide, and hydrogen cyanide.
This is the stuff that volcanoes belch out. This atmosphere poses
a much more difficult challenge. Molecules relevant for life would
be much rarer. Even more damaging is the possibility of the
presence of molecular oxygen in the atmosphere from the break-up of
water vapor. Molecular oxygen would poison any reaction leading to
biologically significant molecules.
Coacervates, microspheres, the "RNA world," and other scenarios all
have serious flaws obvious to everyone in the field except those
who continue work with that particular scenario. Some have
privately called this predicament a paradigm crisis. There is no
central competing model, just numerous ego-driven scenarios. Even
the experiments in which researchers try to simulate the early
earth have been severely criticized. These experiments generally
hedge their bets by using purified reactants, isolated energy
sources, exaggerated energy levels, procedures which
unrealistically drive the reaction toward the desired product and
protect the products from the destructive effects of the energy
sources which produced them in the first place.
The real situation was summed up rather well by Klaus Dose:
More than 30 years of experimentation on the origin of
life in the fields of chemical and molecular evolution have led to
a better perception of the immensity of the problem of the origin
of life on earth rather than to its solution. At present all
discussions on principal theories and experiments in the field
either end in stalemate or in a confession of ignorance." [From
Interdisciplinary Science Review 13(1988):348-56.]
But all of these difficulties together, as staggering as they are,
are not the real problem. The major difficulty in chemical
evolution scenarios is how to account for the informational code of
DNA without intelligence being a part of the equation. DNA carries
the genetic code: the genetic blueprint for constructing and
maintaining a biological organism. We often use the terms of
language to describe DNA's activity: DNA is "transcribed" into RNA;
RNA is "translated" into protein; geneticists speak of the "genetic
code." All these words imply intelligence, and the DNA
informational code requires intelligent preprogramming, yet a
purely naturalistic beginning does not provide such input. Chemical
experiments may be able to construct small sequences of nucleotides
to form small molecules of DNA, but this doesn't make them mean
anything. There is no source for the informational code in a
strictly naturalistic origin of life.
The Inability to Account for Complex Adaptations
Perhaps the single greatest problem for evolutionary biologists is
the unsolved problem of morphological and biochemical novelty. In
other words, some aspects of evolutionary theory describe
accurately how existing organisms are well adapted to their
environments, but do a very poor job of explaining just how the
necessary adaptive structures came about in the first place.
Darwinian explanations of complex structures such as the eye and
the incredible tongue of the woodpecker fall far short of
realistically attempting to explain how these structures arose by
mutation and natural selection. The origin of the eye in
particular, caused Darwin no small problem. His only suggestion was
to look at the variety of eyes in nature, some more complex and
versatile than others, and imagine a gradual sequence leading from
simple eyes to more complex eyes. However, even the great Harvard
evolutionist, Ernst Mayr, admits that the different eyes in nature
are not really related to each other in some simple-to-complex
sequence. Rather, he suggests that eyes probably had to evolve over
forty different times in nature. Darwin's nightmare has never been
solved. It has only been made 40 times more frightening for the
evolutionist.
In his 1987 book, Theories of Life, Wallace Arthur said:
One can argue that there is no direct evidence for a
Darwinian origin of a body plan--black Biston Betularia
certainly do not constitute one! Thus in the end we have to admit
that we do not really know how body plans originate.
In 1992, Keith Stewart Thomson wrote in the American
Zoologist that:
While the origins of major morphological novelties
remain unsolved, one can also view the stubborn persistence of
macroevolutionary questioning...as a challenge to orthodoxy:
resistance to the view that the synthetic theory tells us
everything we need to know about evolutionary processes.
The ability to explain major morphological novelties is not the
only failing of evolutionary theory. Some argue that molecular
structures are even more difficult to explain. The molecular
architecture of the cell has recently described by molecular
biologist Michael Behe as being irreducibly complex systems which
must have all the components present in order to be functional. The
molecular workings of cilia, electron transport, protein synthesis,
and cellular targeting readily come to mind. If the systems are
irreducibly complex, how do they build slowly over long periods of
time out of systems that are originally doing something else?
While publishing hundreds of articles pertaining to molecular
homology and phylogeny of various proteins and nucleic acids over
the last ten years, the Journal of Molecular Evolution did
not publish one article attempting to explain the origin of a
single biomolecular system. Those who make molecular evolution
their life's work are too busy studying the relationship of the
cytochrome c molecule in man to the cytochrome c molecule in
bacteria, rather than the more fundamental question of where
cytochrome c came from in the first place!
Clearly then, whether we are talking about major morphological
novelties such as the wings of bats and birds, the swimming
adaptations of fish and whales, the human eye or the molecular sub-
microscopic workings of mitochondria, ribosomes, or cilia,
evolutionary theory has failed to explain how these structures
could arise by natural processes alone.
The Bankruptcy of the Blind Watchmaker Hypothesis
In his 1986 book, The Blind Watchmaker, Richard Dawkins
states, "Biology is the study of complicated things that give the
appearance of having been designed for a purpose." He explains that
Natural selection is the blind watchmaker, blind
because it does not see ahead, does not plan consequences, has no
purposes in view. Yet the living results of natural selection
overwhelmingly impress us with the appearance of design as if by a
master watchmaker, impress us with the illusion of design and
planning.
Darwinism critic, Philip Johnson, has quipped that the watchmaker
is not only blind but unconscious!
Dawkins later suggests just how this process may have brought about
the development of wings in mammals. He says:
How did wings get their start? Many animals leap from
bough to bough, and sometimes fall to the ground. Especially in a
small animal, the whole body surface catches the air and assists
the leap, or breaks the fall, by acting as a crude aerofoil. Any
tendency to increase the ratio of surface area to weight would
help, for example flaps of skin growing out in the angles of
joints...(It) doesn't matter how small and unwinglike the first
wingflaps were. There must be some height, call it h, such that an
animal would just break its neck if it fell from that height. In
this critical zone, any improvement in the body surface's ability
to catch the air and break the fall, however slight the
improvement, can make the difference between life and death.
Natural selection will then favor slight, prototype wingflaps. When
these flaps have become the norm, the critical height h will become
slightly greater. Now a slight further increase in the wingflaps
will make the difference between life and death. And so on, until
we have proper wings.
This can sound rather seductively convincing at first. However
there are three faulty assumptions being used.
The first doubtful assumption is that nature can provide a whole
chain of favorable mutations of the precise kind needed to change
forelimbs into wings in a continuous line of development. What is
the larger miracle, an instantaneous change or a whole series of
thousands of tiny changes in the proper sequence?
The other assumption is "all things being equal." These mutations
must not have secondary harmful effects. How is the creature's
grasping ability compromised while these wingflaps grow? These
little shrew-like animals may slowly be caught between losing their
adaptiveness in the trees before they can fully utilize their
"developing" wings. Or there might be some seemingly unrelated and
unforeseen effect that compromises survivability.
A third faulty assumption is the often used analogy to artificial
selection. "If artificial selection can do so much in only a few
years," so the refrain goes, "just think what natural selection can
do in millions of years." But artificial selection works because it
incorporates foresight and conscious purpose, the absence of which
are the defining qualities of the blind watchmaker. In addition,
artificial selection actually demonstrates the limits to change
since an endpoint in the selection process is usually reached very
quickly.
The blind watchmaker hypothesis, when analyzed carefully, falls
into the category of fanciful stories that are entertaining--but
which hold no resemblance to reality.
The Prevalence of Stasis over Mutability
Rather than observing organisms gradually evolving into other
forms, the fossil record speaks of "sudden appearance" and
"stasis." New types appear suddenly and change very little after
their appearance. The rarity of gradual change examples in the
fossil record were revealed as the trade secret of paleontology by
Steven J. Gould of Harvard. Gould also refers to stasis as "data"
in the paleontological sense. These are significant observations.
Darwin predicted that there should be innumerable transitional
forms between species. But the reality of paleontology (the study
of fossils) is that new forms appear suddenly with no hint of the
"gradual" change predicted by evolution. Not only that, but once
these new forms have appeared, they remain relatively unchanged
until the present day or until they become extinct.
Some animals and plants have remained unchanged for literally
hundreds of millions of years. These "living fossils" can be more
embarrassing for the evolutionist than they often care to admit.
One creature in particular, the coelacanth, is very instructive.
The first live coelacanth was found off the coast of Madagascar in
1938. Coelacanths were thought to be extinct for 100 million years.
But most evolutionists saw this discovery as a great opportunity to
glimpse the workings of a tetrapod ancestor. Coelacanths resemble
the proposed ancestors of amphibians. It was hoped that some clues
could be derived from the modern coelacanth of just how a fish
became preadapted for life on land, because not only was there a
complete skeleton, but a full set of internal organs to boot. The
results of the study were very disappointing. The modern coelacanth
showed no evidence of internal organs preadapted for use in a
terrestrial environment. The coelacanth is a fish--nothing more,
nothing less. Its bony fins are used as exceptionally well-designed
paddles for changing direction in deep-sea environment, not the
proto-limbs of future amphibians.
Nowhere is the problem of sudden appearance better demonstrated
than in the Burgess Shale found in the Canadian Rockies. The
Burgess Shale illustrates that in the Cambrian period (which
evolutionists estimate as being over 500 million years ago) nearly
all of the basic body plans (phyla) of animals existing on earth
came into existence in a geological instant (defined as only 20-30
million years), and nothing that new has appeared since that time.
The Cambrian explosion as it is called is nothing less than
astounding. Sponges, jellyfish, worms, arthropods, mollusks,
echinoderms, and many other stranger-than-fiction creatures are all
found to suddenly appear in the Cambrian without a hint of what
they descended from nor even how they could all be related to each
other. This is the opposite expectation of Darwinism which would
have predicted each new body plan emerging from pre-existing phyla
over long periods of time. The Cambrian explosion is a direct
contradiction of Darwinian evolution.
If Darwin were alive today, I believe he would be terribly
disappointed. There is less evidence for his theory now than in his
own day. The possibility of the human eye evolving may have caused
him to shudder, but the organization of the simplest cell is
infinitely more complex. Perhaps a nervous breakdown would be more
appropriate!
© 1993 Probe Ministries
About the Author
Raymond G. Bohlin is executive director of Probe Ministries.
He is a graduate of the University of Illinois (B.S., zoology),
North Texas State University (M.S., population genetics), and the
University of Texas at Dallas (M.S., Ph.D., molecular biology). He
is the co-author of the book The Natural Limits to Biological
Change, served as general editor of Creation, Evolution and Modern
Science, and has published numerous journal articles. Dr. Bohlin
was named a 1997-98 and 2000 Research Fellow of the Discovery
Institute's Center for the Renewal of Science and Culture. He can
be reached via e-mail at rbohlin@probe.org.
What is Probe?
Probe Ministries is a non-profit corporation whose mission is to reclaim the
primacy of Christian thought and values in Western culture through media,
education, and literature. In seeking to accomplish this mission, Probe provides
perspective on the integration of the academic disciplines and historic
Christianity.
In addition, Probe acts as a clearing house, communicating the results of
its research to the church and society at large.
Further information about Probe's materials and ministry may be obtained by
writing to:
Probe Ministries
1900 Firman Drive, Suite 100
Richardson, TX 75081
(972) 480-0240 FAX (972) 644-9664
info@probe.org
www.probe.org
Copyright (C) 1996-2008 Probe Ministries
Email this to a friend
copyright
© 1995-2008
Leadership U. All rights reserved.
Updated: 14 July 2002
|