Designed to inhabit the earth
A review of The Plausibility of Life: Resolving Darwin’s Dilemma
by Marc W. Kirschner and John C. Gerhart
Yale University Press, New Haven, CT, 2005
reviewed by Jean K. Lightner
Kirschner is professor and chair of the Department of Systems Biology at Harvard
Medical School. Gerhart is a professor in the Department of Molecular and Cell Biology
at the University of California. Systems Biology is an important field which studies
relationships and interactions between various components of biological systems.
Research in this field and molecular and cell biology are very important to advancing
a creationist understanding of the world God created and still sustains despite
the Curse.1 This book attempts
to provide a naturalistic explanation for the origin of novelty, but many of the
observationally based details are valuable to creationists.
The authors begin with the standard evolutionary assumptions that there were no
witnesses to the origin of life, there is no creator, and that all of life shares
a common ancestor. In the introduction the arguments of William Paley are reviewed.
The authors propose that living things are fundamentally different from the watch.
They compare biological clocks to man made clocks (pp. 5–7). They point out
that time keeping devices invented in different cultures or eras often have different
components (e.g. the Chinese water clock, the pendulum grandfather clock, the watch
driven by an uncoiling spring and the quartz watch) although they have the same
basic purpose. They then point out that biological clocks share many of the same
components although they may be used differently in different organisms. It is as
if they are oblivious to the fact that human engineers commonly reuse good design
elements, with modification as necessary, in distinct creations. Apparently they
have predetermined that a Divine Creator would not be likely to use such techniques.
Yet this shallow argument is the strongest they have for maintaining their evolutionary
assumptions.
Sources of variation
Photo by Karunakar Rayker, www.sxc.hu
Being evolutionists, the authors fail to mention that limits to variation are also
observed. Genetic adaptation to one environment can limit future adaptations to
a different environment. The yak is well adapted to cold climates and high altitudes.
Given the genetic changes it carries, it would not be expected that its descendants
can become well adapted to hot environments like zebu cattle have.
The authors state that Darwin’s theory of evolution has three pillars: the
theory of natural selection, the theory of heredity, and the theory of generating
variation so natural selection has something to work on. The authors imply the first
two are evidence for evolution and fail to recognize their importance in the creation
model. The source of variation is admitted as being a major weakness of evolution,
and the authors attempt to correct this deficiency in their book. They do this by
advancing the theory of facilitated variation.
The authors state:
‘By facilitated genetic variation, we mean genetic variation that
would be (1) biased to be viable … ; (2) biased to give functional outcomes;
and (3) biased to be relevant to the environmental conditions [emphasis in original]’(p.
13).
Examples are then given of previous efforts at finding such a mechanism. Lamarck’s
idea of inheritance of acquired characteristics is discussed along with the evidence
that eventually led to it being rejected. The authors mention directed mutations,
but claim that stressful conditions increase mutation rates in all genes
and that no hint of directed genetic change has been found. The development of the
Modern Synthesis is discussed. It is claimed that by 1940 the fossil record had
grown and many gaps were filled. Archaeopteryx is suggested as implying
a smooth transition between reptile and birds. They appear unaware that evolutionists
in this field have pointed out that it is not transitional, but clearly a perching
bird.2 Other dubious examples
of feathered dinosaurs are presented as well.3
This chapter is heavy on the evolutionary storytelling, and the shallow examples
used are adequately addressed within existing creationist literature. The authors
conclude the chapter by stating that
‘ … genetic variation is not channeled toward adaptation to selective
conditions. Whatever bias there is to alter the amount and kind of phenotypic variation
must arise out of the construction of the organism itself’(p. 34).
Conserved core processes
Chapter 2 examines the construction of various creatures beginning with comparisons
at the genome level. One of the surprises of genome comparisons is the large number
of genes that are shared by many ‘divergent’ life forms. For example,
we share with bacteria many biochemical reactions such as those for energy metabolism,
biosynthesis, and DNA replication and transcription. Eukaryotes share components
of cell structure including organelles and cytoskeletons. There are also certain
features shared by all multicellular organisms, others shared by all organisms with
body symmetry, and still others by organisms with appendages. As these similarities
are presented in moderate detail the authors imply there is only one possible explanation,
common descent. The similarities at each level are described with no attempt to
explain their origin; it is merely taken on faith that only naturalistic processes
were required.
From a creationary perspective, the re-use of good design elements is consistent
with a single Creator (and brings Him great honour).1 It provides an
underlying continuity in living things which also display considerable diversity.
In a world where animals derive their sustenance from plant and (since the Fall)
sometimes animal sources, this continuity undoubtedly simplifies the processes of
digesting and assimilating nutrients. It has also proved to be a tremendous blessing
in terms of research. Studies with bacteria or animals often yield information which
directly impacts human health. For example, animal models of human disease and animal
testing of drugs have greatly enhanced our understanding of disease and pharmacology.
Additionally, bacteria can be engineered to produce valuable products including
human insulin.
Physiologic adaptability preceding evolution
The third chapter begins by describing how organisms are equipped with the ability
to adapt physiologically to various environments. James Baldwin is discussed in
relation to the Baldwin effect. This posits that environmental stress results in
physiologic changes to relieve the stress; then heritable (genetic) changes follow
which are selected for as they stabilize, refine and extend the somatic adaptation.
Ivan Schmalhausen pointed out that environmental stress can induce either adaptive
or nonadaptive changes. Various experiments are presented to illustrate these concepts.
It is mentioned that leading evolutionary biologists were unimpressed with these
ideas. One problem was that they failed to explain major anatomical rearrangements.
Yet the authors have faith that these processes, when combined with the conserved
core process, have the potential to resolve such evolutionary problems as the origin
of complex novelty.
Much of the discussion in this section is empirically based and quite fascinating.
As a creationist very interested in understanding intrabaraminic (within kind) variation
and changes throughout history, I find the authors conclusions consistent with much
of my own thinking and helpful in further extending it.
‘The organism is not robust because it has been built in such a rigid manner
that it does not buckle under stress. Its robustness stems from a physiology that
is adaptive. It stays the same, not because it cannot change but because it compensates
for change around it. The secret of the stability of the phenotype is dynamic restoration.
Mutations or genetic reassortments that target these dynamic restorative systems
can reset their optima and generate a class of significant phenotypes with reduced
lethality. Evolution can achieve new forms of somatic adaptation so readily because
the system, at all levels, is built to vary’ (pp. 107–108).
Evolutionists can describe changes in living things that are designed to vary, but
they cannot give a rational explanation for how this design arose by naturalistic
means. On the other hand, creationists who recognize that living things were created
according to their kind by an infinitely wise Creator5 who cares for them (even
in a fallen world) and intends the earth to be inhabited have a logical explanation
for why biological systems were built thus.
Life cannot survive unless it is designed to vary. This involves far more complex
construction than Paley’s watch. Evolutionists can describe changes in living
things that are designed to vary, but they cannot give a rational explanation for
how this design arose by naturalistic means. On the other hand, creationists who
recognize that living things were created according to their kind4 by an infinitely wise Creator5 who cares for them (even in a fallen world)6 and intends the earth to be inhabited7 have a logical explanation for why biological
systems were built thus. The types of changes suggested here by these authors probably
have played a significant role in intrabaraminic changes.
One thing the authors fail to discuss is that these types of genetic changes are
likely to constrain further adaptations. For example, within the cattle monobaramin,
the yak is adapted to cold temperatures and high altitudes. It is unlikely that
further adaptation and selection will be able to transform the yak into something
able to withstand high temperatures like Zebu cattle. Adaptation can be extremely
beneficial in allowing an organism to exploit a new environment, but it can come
at a cost by restricting its ability to thrive in a wider range of environmental
conditions. This has been shown experimentally where dramatic adaptive changes are
associated with a deterioration of biochemical pathways.8
Weak regulatory linkage
The authors describe weak linkage as meaning, ‘an indirect, undemanding, low
information kind of regulatory connection, one that can be easily broken or redirected
for other purposes’ (p. 111). Then they launch into a fascinating discussion
of the control of gene function and cellular responses to signals in embryology.
Essentially, signals give direction as to the timing and level of expression; they
don’t actually carry the information for what is to be expressed. In gene
regulation, there is
‘… the linkage of several transcriptional regulators and genes into
complex circuits, including circuits in which certain regulators control the expression
of genes encoding other regulators. These circuits can have logical and operational
features like those in computers’ (p. 119).
Allosteric proteins are described first in their importance in feedback inhibition.
The authors view these types of protein as important because they have separate
active sites and regulatory regions. They propose that these two sites are free
to evolve separately and the protein can be modified and recruited for use in new
reactions. They believe that changes in regulatory mechanisms are responsible for
considerable evolutionary change. Because the authors don’t use as many detailed
examples in this portion of the discussion, creationists may be tempted to dismiss
this idea. However, the authors point out that two similar species of Drosophila
which express genes very similarly have significant sequence differences in the
DNA of the regulatory region of the genes. Therefore, it is definitely worth further
examining these types of changes to clarify their significance.
Exploratory behaviour
The authors describe how living things make use physiologically of trial and error
methods to accomplish certain goals. They first explain this in relation to the
cytoskeleton of cells. The cytoskeleton of cells is generally made up of what appears
to be a chaotic array of filaments that give the cell its general shape. However,
these filaments are by no means static; they are constantly being built and torn
down. While the orientation of new filaments is random, there are factors which
can stabilize the filaments to prevent their breakdown. In areas where these stabilizing
factors exist, there is an abundance of filaments and this influences the shape
of the cell. Since the presence of these factors can change, the cell shape can
also change over time. Thus, the DNA doesn’t encode exact placement of these
filaments, but the general rules which govern the behaviour of the filaments.
Photos courtesy www.wikipedia.org
Creationists have often pointed out that there is considerable variety within created
kinds. The Plausibility of Life draws from observational data to illustrate
how life is constructed at a molecular level to facilitate these types of changes.
Thus, many traits seen today need not have been apparent at creation. Instead, much
of the ability to vary and adapt was programmed in from the beginning.
There is a good description of how these processes of trial and error coupled with
responses to signals are important in the development of vasculature and nervous
tissue. Indeed, these processes are common throughout the body and are also critical
in wound repair and physiologic adaptation. The authors muse, ‘The principles
of variation and selection, so powerful a metaphor for evolution itself, are widely
employed in many conserved core processes … ’ (p. 153). Despite this
poetic attempt to link these attributes to evolution, in the real world this is
an important strategy of problem solving that is often employed by intelligent beings.
For example, computer programmers use this type of method to design applications
able to deal with future uncertainties. It is clear that this design in living things
is critical to their ability to survive and respond appropriately to various environmental
challenges.
The authors declare, ‘That exploratory processes lower the hurdle for generating
novelty is well illustrated by the evolution of the vertebrate limb’ (p. 171).
Of course common ancestry of all vertebrates is assumed and the origin of the limb
itself is not explained. However, they point out that genetic changes that affect
the shape of bones do not necessarily require simultaneous genetic changes affecting
nerves, muscles, and vessels because of the design in how these structures develop.
So bones may lengthen or shorten, fuse or divide, and the supporting structures
would still be available to them. While to some degree this is true, it doesn’t
make the suggestion of common ancestry significantly more appealing since there
are considerably more anatomical changes necessary than variation in limb bones
and their associated structures. However, it is likely that this explains a fair
amount of intrabaraminic variability. For example, muzzle shape can vary considerably
in dogs and still remain functional. Additionally, this suggests that variation
in the digits of equines may have a relatively simply underlying genetic basis.
Invisible anatomy
Chapter 6 delves into some details of embryology. Early in embryonic development
a ‘map’ appears in the embryo. Cells are divided up in compartments
and this controls the development of anatomy. The compartments are distinct in that
there are some genes (or gene combinations) that are only expressed in particular
compartments. At this point the different regions are not directly observable, so
they are called invisible anatomy. Yet they orientate the embryo (i.e. head vs tail,
back vs front) and control future development. The hox genes are involved in controlling
the development of this map and are very conserved. Insects have one cluster of
eight kinds of hox genes, vertebrates have four clusters of 13 genes. The same gene
that regulates development of the anterior part of the head in Drosophila
is expressed in the mammalian forebrain and midbrain. Keeping the assumption of
common ancestry, though they have no convincing explanation for how such genes arose,
the authors give a description of what they believe a common ancestor looked like.
They then explain how this design allows for future changes.
The most significant novelty, the ‘preexisting poised processes’ (p.
242) that allow for facilitated variation, have no explanation. If the authors had
not continually expressed their faith in common ancestry and a naturalistic origin
of life, one might think that this was a creationary model since it provides a plausible
designed basis for intrabaraminic change.
‘Compartmentation is a form of modularity, which is a common strategy in many
designs. By subdividing the animal into smaller, largely independent domains, the
evolution of structures in that domain can be uncoupled from the evolution of structures
in other domains … Segregation and specialization reduce the so-called pleiotropy
problem, that is, the problem of a mutation having conflicting effects in different
regions of the embryo, where a positive change in one place might provoke a negative
change in another’ (p. 203).
Facilitated variation and the plausibility of life
The final two chapters sum up what has been presented in the book and attempt to
leave the reader with a naturalistic explanation for variability and the origin
of novelty. The authors give several nice examples of intrabarminic changes that
fit well with the theory they have presented. However, it is blatantly obvious that
the most significant novelty, the ‘preexisting poised processes’ (p.
242) that allow for facilitated variation, have no explanation. If the authors had
not continually expressed their faith in common ancestry and a naturalistic origin
of life, one might think that this was a creationary model since it provides a plausible
designed basis for intrabaraminic change. While recognizing a religious base to
‘creationism’, the authors are oblivious to the religious (atheistic)
base of their own evolutionism. It further appears they are ignorant of the biblical
creation model.
Nevertheless, the majority of what they present is very relevant to creationists
and clearly inspires awe for the incredible design God placed in living things.
Here is just one of their many statements that creationists could heartily agree
with:
‘Genetic variation or mutation does not have to be creative; it only needs
to trigger the creativity built into the conserved mechanisms’ (p. 227).
Related articles
Further reading
References
- For a discussion of this subject in its broader context see
Williams, A., Facilitated variation:
A new paradigm emerges in biology, Journal of Creation 22(1):85–92,
2008. See Holding, J.P.,
‘Not to be used again’: homologous structures and the presumption of originality
as a critical value, Journal of Creation 21(1):13–14,
2008. Return to text.
- Sarfati, J, Refuting Evolution, Master Books, Green Forest, AR,
Ch. 4, 1999.
Return to text.
- Sarfati, J.,
Archaeoraptor—Phony ‘feathered’ fossil, 19 October 2007.
Return to text.
- Genesis 1:20–27. Return to text.
- Romans 16:27; 1 Timothy 1:17. Return to text.
- Psalm 147:8–9; Matthew 6:25–34. Return to text.
- Genesis 8:17; Isaiah 45:18. Return to text.
- Lightner, J., Special tools
of life, 12 May 2004, 19 October 2007. Return to text.
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