Institute
for Christian Teaching
Education
Department of Seventh-day Adventists
By
Centro Universitário
Adventista de São Paulo
São Paulo, Brazil
431-00 Institute for
Christian Teaching
12501 Old Columbia Pike
Silver Spring, MD 20904 USA
Prepared
for the
26th
International Faith and Learning Seminar
held
at the
Geoscience
Research Institute, Loma Linda, California, U.S.A.
July
16-28, 2000
Zoology and genetics are required
courses for biology majors, and genetics is required in the programs of several
courses in health areas, such as Medicine, Nursing, Dentistry, Psychology and
others. Both subjects are usually structured around the theme of the theory of
evolution. Also, the majority of the textbooks used in the teaching of these
two courses have an evolutionary orientation. However, a careful examination of
the scientific basis of these disciplines shows that the evolutionary framework
doesn't fit with a lot of their fundamental aspects. Some of these topics even
constitute strong evidence in favor of intelligent design. The objective of
this paper is to analyze these topics to see why they provide good evidence
that is consistent with a creation model for the origin of life.
The science of Zoology deals with
the study of animal life. The whole study of Zoology is now structured around
the theory of evolution, according to which all the present animals would have
developed from unicellular common ancestors (protozoa). The present animal
taxonomy (classification) is based on phylogeny, i. e., and the evolutionary
history of a group.
If all animals developed from common ancestors,
ideally, one expects to find several series of links connecting different
groups of organisms. However, that is not what we find in the fossil record
(Brand, 1997, p.141).
Darwin recognized that the fossil record did
not show much evidence for connecting links. He thought that as more fossil
collecting was done over time, these links would be found. In his book
"Origin of species" he says: "Lastly, looking not to
any one time, but to all time, if my theory be true, numberless intermediate
varieties, linking most closely all the species of the same group together,
must assuredly have existed; but the very process of natural selection
constantly tends, as has been so often remarked, to exterminate the parent
forms and the intermediate links. Consequently evidence of their former
existence could be found only amongst fossil remains, which are preserved in an
extremely imperfect and intermittent record" (Darwin, p. 179).
"Nature may almost be said to have guarded against the frequent discovery
of her transitional or linking forms" (Darwin, p. 292). "Geological
research (…) has done scarcely anything in breaking down the distinction
between species, by connecting them together by numerous, fine, intermediate
varieties; and this not having been effected, is probably the gravest and most
obvious of all the many objections which may be urged against my views"
(Darwin, p. 299).
In the 130 years since Darwin's prediction, many fossils have been
collected. This improved database still suggests that, for most animals, the
fossil record does not contain connecting links between types (Brand, 1997, p.
143).
One of the most important fossil gaps is the
one between the microorganisms, such as blue-green algae and bacteria, that are
found in Precambrian strata, and the abundant and complex invertebrate sea life
of the Cambrian period, as well as the strange Ediacaran fossils of the
Precambrian (Morris, 1995, p. 81). Almost all of the phyla of invertebrate
animals that have a fossil record occur in the early Cambrian: protozoa,
sponges, cnidarians, mollusks, brachiopods, annelids, arthropods and
echinoderms. The only major absent phylum is the Bryozoa, which appears in the
Ordovician (McAllester, 1971, p. 70). If evolution had really occurred, we
should find in Precambrian rocks the evolutionary ancestors of all these
animals. According to Axelrod (1958), the high degree of organization of the
Cambrian animals clearly indicates that a long evolutionary period preceded
their emergence in the fossil record. However, an examination of the
Precambrian rocks for precursors of Cambrian fossils indicates they are not
found anywhere. The majority of the fossils found in the Precambrian rocks are
fossil microorganisms. Only in the top of the Precambrian some multicelular
fossils are found. Among them are the Ediacaran fauna, including cnidarians,
annelids and arthropods. They are multi-celled animals, but they are not
considered ancestral to the Cambrian animals (Gould, 1989; Seilacher, 1984).
They are a unique, extinct assemblage of animals with no clear ties to other
groups (Brand, p. 143, 1997).
If we find fossils of bacteria and blue-green algae in the Precambrian,
certainly we should find fossils of the ancestors' of the Cambrian animals. If
microorganisms evolved into metazoans, it seems likely that transitional forms
should have been found but they have not. The sudden appearance of the major
phyla in the Cambrian has been called the "Cambrian explosion".
Recently the estimated time over which the explosion took place has been
revised downward from fifty million to ten million years ¾ a
blink of the eyes in geological terms. The shorter time estimate has forced
sensationalist writers to seek new superlatives, a favorite being the
"Biological Big Bang" (Behe, 1996, p. 27). Gould has argued that the
fast rate of emergence for new life forms demands a mechanism other than
natural selection for its explanation (Beardsley, 1992). Futuyama (1992, p.
343) says that the fast origin of the animal phyla, which happened in the 100
million years between the Ediacaran fauna and the Burgess Shale fauna
(Cambrian), has been considered one of the biggest problems of evolution. The
theory of separate creation of each group explains the evidence better than the
theory of a single ancestor.
Wise (1994) also considers the Cambrian explosion a challenge to explain
without informed intervention (creationism). Interventionist theory proposes
that the Cambrian explosion is not a record of the first appearance of life,
but the first burials during a catastrophe, the Genesis Flood (Brand, 1997, p.
172).
Another serious problem of the fossil record
that has not been explained by evolutionists is that most animal groups appear abruptly in the
fossil record. There is no evidence that there were transitional forms among
these groups. This is well recognized today by science. Brand (1997, p. 173) calls attention to
phylogenetic trees that are in many texts and popular books. Some of them show
which parts are supported by fossil evidence and which parts are hypothetical. Such
trees show that the evolutionary connections between virtually all phyla and
almost all classes are only theoretical. Charles Darwin believed the
intermediates would be found. However, most of the thousand of
fossils that are found fall within the existing groups. As more fossils are
found it becomes clearer that gaps between major groups of organisms are real
and sequences of intermediates are not likely to be found. This evidence has
caused evolutionary theorists to look for new ways to explain the evolution of
major groups consistent with the reality of the lack of fossil intermediates.
Considering the invertebrate animals, the lack
of fossil links is very clear, because almost all the invertebrate animal phyla
appear in the Cambrian. Particularly interesting is the phylum Echinodermata.
Ruppert & Barnes (1994, p. 988) say the origin of the echinoderms and the
phylogenetic relationships of its subgroups continue to be unresolved and the
subject of much speculation. Storer et al (1991, p. 547) in their book Zoologia
Geral, a frequently used textbook, say that the echinoderms are an old
group of animals with an abundant fossil record since the Cambrian. However,
the fossils don't indicate origin or relationships of this phylum. The phylum
Echinodermata is considered the ancestor of the phylum Chordata. These two
phyla are the only deuterostome phyla and they also share other
characteristics, i. e., the presence of similar larvae and endoskeletons. It
would be expected then that the phylum Echinodermata should appear much higher
in the fossil record than the other invertebrate phyla, but this is not what is
seen in the fossil record.
The transition between echinoderms and
chordates is also a great mystery in evolutionary Zoology. Zoologists admit the absence
of any intermediate forms in the fossil record. Only a few types of chordate
remains has been found in Cambrian rocks (Repetski, 1978). More chordates
appear higher in the fossil record and are identified as the ostracoderm fish
in the Ordovician and Silurian. Evolutionists suppose that the first chordates
probably had soft bodies, without hard skeleton elements to be preserved.
Storer et al (1991, p. 567) places the problem in the following way: "If
chordate ancestry consist of such small and soft types, the chance of finding
any conclusive fossil record is remote. So we remain in the unsatisfactory
position of being capable of demonstrating a certain relationship on an
embryological level, however without conclusive evidences in the fossil forms
or in the intermediate forms. Maybe this theory [of the origin of the chordates from the echinoderms] is correct, but it cannot
be proven". Alfred Romer (1966, p. 15) made the following
comment many years ago: "In sediments at the top of the Silurian and the
beginning of the Devonian, numerous vertebrates similar to fish of several
species are present, and it is obvious that a long evolutionary history took
place before this time. However, regarding this history, we are almost entirely
ignorant". But now we know that both Echinodermata and Chordata phyla
occur in the Cambrian and this provides little time for the proposed evolution.
The origin of the insects is also a great
enigma for the evolutionists. Insects exist in abundant number and fantastic
variety, but there are no fossil indications of their development from any
ancestral specie. Insects that appear in the fossil record are very similar to
modern insects. In many cases, however, they are much larger; but
their form is not very different from that of modern insects (Morris, 1995, p.
86). Storer comments: "The sudden emergence of insects with wings in the
rocks of the Carboniferous is a spectacular aspect of the fossil record.
Several theories have been proposed to explain the origin of insect wings"
(Storer et al, 1991, p.505). Perhaps the authors should have used the word
"strange" in place of "spectacular".
Flying organisms fall into four main groups: insects, pterosaurs, birds
and bats. Flying is a highly specialized function requiring many features
besides wings. One would naturally expect the gradual evolution of flight to
leave some evidence in the fossil record. But when fossil insects first appear
in the geologic column, flying is fully developed (as discussed above). The
flying pterosaurs, birds, and bats also show up suddenly as fully functional
flying organisms. The anatomical changes needed to develop flight, including
transformations in bone, musculature, feathers, respiration, and nervous
system, would take a long time, and the organisms undergoing such changes would
surely leave some fossil record of intermediate stages. The feather of the bird
supposedly evolved from the scales of some ancestral reptile. Would not the
extended process of creating feathers, with its highly specialized structures, from
reptile scales by undirected evolution, including unsuccessful lines of
development, have made some record in the rocks? Thus far, none is apparent
(Roth, 1998, p. 185).
The paleontologist David B. Kitts admitted: "Despite the bright
promise that paleontology provides a means of 'seeing' evolution, it has
presented some nasty difficulties for evolutionists the most notorious of which
is the presence of 'gaps' in the fossil record. Evolution requires intermediate
forms between species and paleontology does not provide them". Stephen Jay
Gould echoes the same: "The extreme rarity of transitional forms in the
fossil record persists as the trade secret of paleontology. The evolutionary
trees that adorn our textbooks have data only at the tips and nodes of their
branches; the rest is inference, however reasonable, not the evidence of
fossils" (Roth, 1998, p. 183).
In spite of the existence of some exceptions to the absence of transition
links that were not discussed here, it can be observed that the general picture
presented in the fossil record favors creation model. In this model, God
created separately the groups of animals, as described in the book of Genesis.
Zoology textbooks express as a fact the changes
that must have happened for the appearance of an animal group starting from
another ancestral group. It is interesting that they do not discuss the mechanisms
by which such changes could have happened and the probabilities of their
occurrence. The description given by Storer et al (1991, p. 469) of the
arachnid's origin can be used as an example: "The fossil record includes
aquatic scorpions from the Silurian. The transition to a terrestrial existence
probably happened early in the geological history (...). As a result of this
transition to a terrestrial existence certain modifications in the anatomy and
physiology of the group occurred. One of the modifications was in the
reproductive system to avoid the loss of water. Fecundation became internal and
the eggs are protected against desiccation by their deposition in humid
cavities in the soil, by the retention in the female (viviparity) or by the
presence of an external wrapper. Free-swimming larval forms are not possible
anymore and the larval stages occur inside the egg (...). Other adaptations
include the development of a more impermeable exo-skeleton to reduce water loss
and the transformation of the original foliaceous gills to foliaceous lungs or
to a tracheal system of aerial breathing". Words such as
"become", "development", "transformation", cause
students to think that all these changes are very simple and happened easily.
Causative factors are not mentioned nor are quantitative details of how these
new structures could really have appeared given. Zoology textbooks are full of
examples like this.
The vertebrate eye is a very complex organ and
for two centuries it has been the focus of discussion as to whether such a
complex structure could result from evolution, or whether it would require
intelligent design. Roth (1998, p.101) gives a very good synopsis of the human
eye functions and complexities. According to Brand (1977, p. 169)
"Octopuses have eyes that rival the vertebrate eyes for complexity.
Vertebrates and octopuses obviously did not get their eyes from a common
ancestor with complex eyes. Could the processes of genetic changes have brought
about the evolution of either or both of these eyes from an ancestor that did
not have complex eyes? One can find animals with eyes of many different levels
of complexity and line them up in a sequence of increasing complexity. The
question remains: Do we actually have evidence that they could and did arise by
evolution, or is that an untested assumption?" On the other hand, creation
provides a good explanation for the complex eyes of vertebrates and octopuses.
Arthropods are animals that have a unique kind of eye called a compound
eye. The trilobites, arthropods found in the beginning of the Cambrian, already
possessed this complex kind of eye. Chadwick (1999) describes the trilobite's
eyes in the following way: "The axis of the individual ommatidia were
constructed of single crystals of calcite with the optical axis of the crystal
coincident with the optical axis of the eye element. That presents an unusual
problem for the trilobite, since a simple thick spherical lens of calcite could
not have resolved the light into an image. The trilobite optical element is a
compound lens composed of two lenses of differing refractive indices joined
along a Huygens surface. In order for such an eye to correctly focus light on
the receptors it would have to have exactly this shape of lens". The most
amazing fact is that a so complex eye was present in one of the first animals
to appear in the fossil record.
In the book "Darwin's Black Box", Behe goes beyond the eye
morphology and shows that, even in animals that possess the simplest kinds of
eyes, i.e. the light sensitive spots of jellyfish, vision is an extremely
complex biochemical process. The evolution of such a complex system cannot be
explained yet (Behe, 1996, p. 22). Creation seems a better explanation.
Behe (1996, p. 39) considers the origin of irreducibly complex systems by
mutation and natural selection impossible. A irreducibly complex system is a
single system composed by several well-matched, interacting parts contributing
to its basic function, wherein the removal of any one of the parts causes the
system to effectively cease functioning. An irreducibly complexity system
cannot be produced gradually (that is, by continuously improving the initial
function, which continues to work by the same mechanism) by slight, successive
modifications of a precursor system, because any precursor to an irreducibly
complex system that is missing a part is by definition nonfunctional.
The same author (Behe, 1996, p.72) analyzes the structure and functioning
of flagella and cilia, locomotory structures present in bacteria and also in
protozoa, which are considered ancestral to all the animal phyla. Flagella and
cilia are also present in several kinds of cells in multicelular animals. An
exhausting biochemical analysis shows that the cilium contains more than two
hundred kinds of different proteins and its complexity is much greater than was
thought. The bacterial flagellum needs more than 40 proteins to work, and the
exact roles of most of the proteins are unknown. The author considers the two
systems as irreducibly complex and he reflects that the probability of
gradually assembling these systems is virtually nil.
Behe
(1996, p. 67) makes an exhaustive review of scientific papers, searching for
research that tries to explain cilium and flagellum evolution. After all, as he
says, "considering the frequent declaration that evolution theory is the
base of modern biology, one should expect to find the evolution of cilium and
flagellum to be the theme of a great amount of works in the professional
literature". However, only two works about cilium evolution are found and
neither of them discusses crucial quantitative details or the possible problems
that would cause any mechanical device such as a cilium to be useless. In the
two works there are just verbal descriptions that characterize evolutionary
biology. The lack of quantitative details ¾ calculations or well-informed estimates ¾ makes the whole description completely
useless for explaining cilium evolution. Considering the flagellum, "Once
again the evolutionary literature is totally missing: no scientist has ever
published a model to account for the gradual evolution of this extraordinary
molecular machine [the
flagellum]" (Behe, 1996, pag.72).
Some people say that the first animals in the Cambrian are primitive.
But does the evidence indicate these earliest fossils were more primitive in
the sense of being more crudely constructed or simpler? No. For example,
trilobites are unique animals found only in the Paleozoic, but they have
compound eyes, complex legs and other features showing they are like arthropods
of today. Evolution theory recognizes that the first fossils in these phyla
already had the basic body plan that the same phyla have today. The term
"primitive" in the evolution theory does not mean crude ¾ it
just refers to animals or structures that appear early in the fossil record
(Brand, 1997, p.173). Complexity is better explained as the result of creation
than evolution.
Genetics can be defined as the study of heredity mechanisms, by which
characteristics are passed from generation to generation. It can also be
defined as the study of the genes. In the last few years many discoveries in
the field of molecular genetics have been made. Some of these discoveries will
be presented here and analyzed to verify whether or not they support the theory
of evolution (that assumes an abiogenic origin of life) or intelligent design
(creation).
DNA replication is the copying of the
information into a new molecule of DNA. It is a very complex process, carried
out by a multi-enzyme complex often called the replication apparatus or the
replisome, which involves several proteins and enzymes. For example, DNA
replication in Escherichia coli
requires at least three dozen different gene products. Some of them are:
(1) DNA
polymerase catalyses the covalent addition of nucleotides to preexisting DNA
chains. In Escherichia coli, there
are three different DNA polymerases (I, II and III). DNA polymerase I has three
activities located in different parts of the molecule. DNA polymerase III is
involved, together with DNA polymerase I, in replicating the DNA. The total complex
of DNA polymerase III, also called holoenzyme, has at least 20 polypeptidic
subunits, although the catalytic core is composed of only three subunits.
(2) Primases are a kind of RNA
polymerase responsible for primer synthesis. Primase activity requires the
formation of a complex of primase and at least six other proteins; this complex
is called the primosome.
(3) DNA
ligase closes the spaces in the DNA molecule during the replication. The short
sections of replicated DNA (Okazaki fragments) are covalently linked together
by DNA ligase.
(4) DNA
helicases are involved in catalyzing the unwinding of the DNA double helices
before replication.
(5) DNA
topoisomerases catalyze the formation of negative supercoils in DNA. They are
essential for replication and are believed to play a key role in the unwinding
process.
(6) DNA
single-strand binding proteins bind tightly to single-strand regions of DNA
produced by the action of the helicases and help stabilize the extended
single-strand templates needed for polymerization (Griffiths et al, 2000, p.
253; Gardner, 1991, p. 119).
We should not forget that in all organisms, even in the simplest
bacteria, the genetic material (genes) is DNA and this DNA should replicate
every time that the cell divides, using all the proteins described above and
many others. How did a replication system as complex as this appear? Science
doesn't have the answers.
Most eucaryotes contain many times the amount
of DNA that prokaryotes have, but this DNA is packaged in several chromosomes.
Each chromosome is composed of a single DNA molecule. Every somatic cell in the
human body has a complement of 46 chromosomes. All the DNA of a single human
cell would extend to nearly two meters if the DNA molecules from all 46
chromosomes were placed end to end. This DNA is housed in a nucleus with a
diameter of about 10 micrometers. So, the length of DNA in the nucleus of a
single human cell is 200,000 times the radius of the nucleus. How can the cell
cope? The DNA must be organized in a very precise way to allow
the cell to have access to the needed genes and at the same time to allow the
DNA to be duplicated, and precisely divided to the daughter cells during cell
division. This process is facilitated at the most basic level by the
association of DNA with a class of proteins called histones. There are five
types of histones: H1, H2a, H2b, H3 and H4. Four types of histones, H2a, H2b,
H3, and H4 with the help of some associated proteins form a very stable octamer
containing two copies of each molecule. Because all of the histones are
positively charged to enable them to interact with the negatively charged DNA,
the assembly of the octamer requires the aid of several special scaffolding
proteins. One and a half turns of the DNA molecule (about 140 base pairs) are
then wrapped around each histone core to form a nucleosome. The nucleosomes are
associated into larger structures by the binding of H1 histone. These
structures, called solenoids, consist of an array of six nucleosomes in a
flattened helix, further shortening the whole structure. These helical
solenoids are then themselves coiled in a complex arrangement that is anchored
to the backbone of the chromosome itself. The chromosome backbone is composed
of a large number of very heterogeneous proteins called nonhistone proteins.
One of these is the topoisomerase II that is also involved in DNA replication.
The resultant structure has accomplished the unfathomable: condensed a molecule
of DNA of 10 cm long into a structure 50,000 times smaller (Chadwick, 1999;
Gardner, 1991, p. 133).
Chromosomes with the complex structure
presented above are already present in protozoa, which are considered ancestors
of all the animal phyla. There is no evidence they evolved from simpler molecules,
and creation is the best explanation for their origin.
From the rediscovery of Mendel's Laws in 1900
until the 1940s, the question of how genes determine an organism's phenotype
remained a mystery. Today we understand that virtually all phenotypic
characteristics of an organism are governed by the activities of
particular proteins. Even the simplest cells contain hundreds of different
proteins. Genes determine phenotypes by dictating the synthesis of proteins.
This process is a very complex one and includes two key steps. First, the
information in DNA is copied into RNA in the process called transcription.
Second, the RNA molecules direct the stepwise assembly of amino acids in the
process of translation (Anderson, 1997, p. 164).
The discovery of the genetic code has shown
how the combinations of four different kinds of the nucleotide bases in code
units of three bases each on the DNA chain can dictate the order of any of the
20 different kinds of amino acids that form a protein (Roth, 1998, p. 137). The
"evolution" of the genetic code is a problem that is very difficult
to solve. How could an organism survive having a under-developed genetic code
that codified correct amino acids as well as wrong ones? How many inactive, useful
enzymes would be produced, wasting valuable cell energy? (Sharp, 1978).
Another problem of the genetic code is
analyzed by evolutionary scientists (Freeland & Hurst, 1998). Statistical
and biochemical studies of the genetic code have found evidence of nonrandom patterns
in the distribution of codon assignment. It has, for example, been shown that
the code is very well structured to minimize the effects of point mutations or
mistranslation: erroneous codons are either synonymous or code for an
amino acid with chemical properties very similar to those of the one that would
have been present had the error not occurred. Codons specifying amino acids
that share the same biochemical synthetic pathway tend to have the same first
base. The authors conclude that the
code is very efficient at minimizing the effects of errors, and this is
probably the result of selection between alternative codes, with selection
favoring those that minimize the errors on fitness. But could natural selection
produce such a precise code? In a sample of one million random variants
generated by the authors, using a computer program, only one variant code was
found to be of greater efficiency under the criteria used. It seems much more
likely that the genetic code was designed.
Early investigators had good reason for thinking that information is not
transferred directly from DNA to protein. In a eukaryotic cell, DNA is found in
the nucleus, whereas protein is known to be synthesized in the cytoplasm. An
intermediate, RNA, is needed. Transcription is the process whereby the
information present in DNA molecules is copied into RNA molecules. Chadwick
(1999) describes the process as follows. "Prior to the development of the
tools and resource of the last twenty years, the process of transcription was
considered to be fairly straightforward. The cell required a new protein, the
RNA polymerase (the enzyme required to make an RNA copy) located the correct
gene, and produced a copy in the form of messenger RNA (mRNA). However, careful
study of the process of messenger formation in eucaryotic cells has revealed
unexpected levels of complexity. How does the cell know which of the million or
so genes present in eucaryotic organisms are needed? How does it locate the
right genes? How does it know precisely where to begin copying? The answer to
these and other questions have come in the unraveling of a system of almost
unfathomable intricacy referred to as the RNA Polymerase Complex". The RNA
Polymerase in E. coli is a complex,
multimeric enzyme. It is composed of five distinct polypeptides. In eucaryotes,
there are three different RNA polymerases I, II, and III.
Translation is the process during which the genetic information (which is
stored in the sequence of nucleotides in an mRNA molecule) is translated,
following the dictation of the genetic code, into the sequence of amino acids
in the polypeptide. The translation process is too intrincated to be described
here. We are just going to mention the necessary components for translation in a
cell, which are:
(1)
Messenger RNA - one for each
gene
(2)
Transfer RNA – from 40 to 60
different kinds
(3)
Aminoacyl tRNA synthetazes -
twenty different kinds
(4)
Initiation factors IF1, IF2
and IF3
(5)
Elongation factors EF-Tu,
EF-Ts and EF-G
(6)
Release factors RF1, RF2 and
RF3
(7)
GTP
(8)
Ribosomes
Just to illustrate the complexity of this
process, Chadwick (1999) explained a little about the ribosome: "The
translation process in all living systems (even in bacteria) requires the
presence of a ribosome, a complex of proteins and ribosomal RNA (rRNA) involved
in the manufacture of proteins. No viable mechanism has yet been proposed to
make specific proteins in the absence of a ribosome, yet ribosomes themselves
are made of more than 50 separate specific proteins, and several very complex
molecules of rRNA. How might it be possible to reproducibly manufacture
proteins in the absence of a ribosome? There does not appear to be an
alternative. The only known mechanism for protein synthesis in the cell is a
factory, itself made out of protein. Where could it originate if there were no
mechanism for protein synthesis? This is an unresolved conundrum". One
should not forget that each one of the 50 types of proteins and the several
rRNA types that form the ribosome are synthesized from genes in DNA.
The process involved in DNA replication, mRNA formation and protein
synthesis, the three most fundamental processes that any cell must perform in
order to be considered alive, are extremely complex, even at the level at which
we now understand them (Chadwick, 1999). Lots of different genes, proteins and
enzymes are involved in this process. How could they evolve by chance? How
could the first cell acquire all this information?
According to Gibson (1993) information stored in the DNA specifies the
structure of the proteins. Without this information, the proteins would not be
produced. But the information to produce the proteins cannot be used unless
numerous proteins are present to help translate the information. This raises a
"chicken and egg" problem. Which came first, the DNA or the proteins?
Without the DNA, there would be no proteins. Without the proteins, there would
be no DNA. How can such a system begin? Both DNA and proteins must be present
simultaneously, along with many other kinds of molecules, in order for life to
exist. Such a system cannot evolve piece by piece. It must appear as an entire
unit. It seems that a Creator is required to explain the origin of life. There
is no plausible alternative.
The process of manufacturing proteins from the information of the genes
is complex and highly regulated (Roth, 1998, p.137). The adaptability of
bacteria depends on their ability to "turn on" and "turn
off" the expression of specific sets of genes in response to the specific
demands of the environmental milieu. The expression of particular genes is
"turned on" when the products of these genes are needed for growth in
a given environment. Their expression is "turned off" when their
products are no longer needed for growth in the existing milieu (Gardner, 1991,
p. 391). Researchers have discovered a number of gene control mechanisms, some
repressing the gene, others activating it. Some genes have more than one
control mechanism. The "lac operon" system, discovered in E. coli, has become a classic example of
a gene control system. It regulates the production of three enzymes employed in
the metabolism of the sugar lactose. The three enzymes are coded next to each
other on the DNA chain. Preceding the codes are four special regions of coded
DNA necessary for regulating and producing the enzymes as needed (Roth, 1998,
p. 137). Gene expression in eucaryotes is more complex and regulated at several
stages, including transcription, translation, mRNA processing, and mRNA
degradation.
Molecular biology shows
that genes are organized in complex interacting systems, including some
feedback mechanisms that would be difficult to develop by a gradual random
evolutionary process because of a lack of survival value until the system is
fully functional (Roth, 1998, p.137). If it's difficult to explain the origin
of a single new gene, what about the simultaneous origin of a regulatory gene
to regulate it? How could the gene function before the evolution of its
regulatory gene?
Mutations can be defined as sudden, heritable
changes in the genetic material. They can be caused by chemicals or radiation.
Mutations can be classified in two types:
(1)
Genic mutations: changes in nucleotides of individual
genes.
(2)
Chromosomic mutation: changes in chromosome structure
or number, also called
chromosomal aberration.
According to the theory of evolution, all new genes or new information
ultimately arose by mutation and recombination. Mutations occur randomly and
most are deleterious and lower the organism fitness or adaptation to its
environment. New combinations of the genetic material are formed during sexual
reproduction. Natural selection eliminates the deleterious mutations and
preserves the available combinations that are best adapted in the organism's
environment (Brand, 1997, p. 191).
Mutation
phenomenon is a very important component of the evolutionary model. This model
needs to presuppose some mechanism that produces the ascending complexity that
characterizes the model in its wider dimension. Mutation is supposedly this
mechanism. According to the theory of evolution, mutation and natural selection
are the main evolutionary factors.
However, some experimental facts about mutations should be considered:
1. Mutations happen by chance; they are
not directed. There is no way to control mutations in order to produce any
specific characteristic. Natural selection needs to use whatever appears.
2. Mutations
are rare. The frequency of most mutations in higher organisms is one in ten
thousand to one in a million per gene per generation.
3. Most
mutations are deleterious.
Chromosomal
aberrations usually have quite drastic effects on the individuals that have
them. With regard to numeric aberrations, the phenotype alterations produced by
the addition or subtraction of one chromosome (aneuploidy) are so drastic that
these aberrations are of no importance in evolution. Polyploidy is very rare in
animals, but in vegetables it can produce new species. Structural chromosomal
aberrations can also have quite serious effects. Small deletions generally
decrease the organism's viability. Duplications are more common and less
harmful than deletions. According to some authors, duplications are a way of
introducing new genes in a population. These new genes could mutate without
causing great damage to the organism, because the non-mutated gene can
synthesize the indispensable enzymes (Carvalho, 1987, p. 404).
Most of the thousands of already studied genic mutations are deleterious
and recessive. It's highly improbable that a mutation could be constructive.
Random changes in any complex integrated system will usually upset the system.
The fact that mutations are usually either neutral or harmful contradicts the
view that mutation is a mechanism for the advancement of a species (Webster,
1995, p. 12).
Even though most mutations make the organism less efficient and are thus
disadvantageous, there is the possibility of developing new desirable traits
through selection of desirable mutations, mainly in plants. Barley mutants, for
example, have been obtained that provide increased yield, resistance to smut,
stiff straw, increased protein content, and hull-less seeds (Gardner, 1991, p.
314). These mutations are selected by changing the environment to favor them,
not by guiding the mutation to fit the environment.
Some mutations are neutral; in other words, they don't reduce the
species survival.
For a species to become more complex requires
more than simply a mutation in a gene; it requires new genes. It is true that
mutations generate new variation by altering existing genes or introducing new
alleles. But that doesn't demonstrate that the same process can produce
structural genes that did not exist before or alter them systematically to the
point where they acquire a new function. Even if a new gene could be produced,
simply adding a new gene would not work. Genes do not work in isolation.
Rather, an organism's set of genes work together to produce the organism. A new
gene must work properly with all the other genes in order for the organism to
survive. Furthermore, several new genes would be required in order to produce a
new structure and a more complex organism. Such a process would have to produce
additional genes to recognize and regulate the functioning of the new
structural genes and repeat the process for all the new genes needed to code
for some new structure or body plan that previously did not exist. In addition,
each new gene would have to operate at the right time in development for the
new structure to develop correctly. It does not seem reasonable to expect even
one new gene to appear by chance, much less several highly coordinated genes
working together to produce a new structure (Brand, 1997, p. 171;
Webster, 1995, p. 13).
Creationism predicts that mutation and natural
selection are not able to produce an increase in complexity by generating new
genes and consequently, new structures and new organisms. They are able only to
change animals within the constraints of their original genetic
potential and to slow down the slide toward oblivion, which would occur if the
accumulations of harmful mutations were not held in check. Natural selection
acts as a brake to eliminate many individuals weakened by mutations and thus
slows down the destructive forces that can come from mutation (Brand, 1997, p.
197).
We've given here just a small sampling of the
thousands of examples that could be given about complex structures in animals
and about the intricacy of gene expression.
What is the best explanation for these examples? Behe concludes that:
"To a person that doesn't feel obliged to restrict his search to
unintelligent causes, the straightforward conclusion is that many of these
systems were designed. They were designed not by the laws of nature, not by
chance and necessity; rather, they were planned. The designer knew what the
systems would look like when they were completed, then took steps to bring the
systems about. Life on earth at its most fundamental level, in its most
critical components, is the product of intelligent activity" (Behe, 1996,
p. 193).
Gibson (1993) also concludes that it is credible to believe in special
creation by an intelligent Creator. He does not mean to imply that every aspect
of biblical creationism is supported by science because there are some aspects
of nature that remain unexplained. However, there is no alternative theory that
explains all the data.
According to Paul in Romans, nature is clearly designed, but not all are
open to recognize the Designer. Nature can be properly understood only in the
light of God's special revelation in the Scriptures (White, p. 257). Genetics
and Zoology professors have the opportunity to explain to their students the
evidences of God's creative power in nature. Unfortunately, the available
textbooks have an evolutionary orientation and don't help in the integration of
faith and learning. So, what can be done? In Zoology textbooks, in the
beginning of the presentation of each animal phylum, a small description of the
evolution of each group is given. The professor can use this section as a
platform for discussion of the lack of fossil evidence for the evolution. Also,
when describing the morphological structures of each phylum, s/he can present
or illustrate the design evidence. When teaching Genetics, many evidences of
intelligent design can be shown in the complex genetic systems present in all
living organisms.
ANDERSON,
P. & GANETZKY, B. An electronic companion to genetics workbook. New
York, Cogito Learning Media, 1997.
AXELROD,
D. I. Early Cambrian marine fauna. Science,
128:7, 1958.
Beardsley, t. Weird wonders: was the
Cambrian explosion a big bang or a whimper? Scientific American, June 1992, p 30 – 31.
BEHE,
M. J. Darwin's black box. New York,
The Free Press, 1996.
BRAND,
L. Faith, reason and earth history.
Berrien Springs, Andrews University Press, 1997.
CARVALHO, H. C. Fundamentos de genética e evolução. 3th
ed. Rio de Janeiro, Livraria Atheneu, 1987.
CHADWICK, A. Os
trilobitas: um enigma de complexidade. Folha criacionista, 61: 3 – 11 1999.
DARWIN,
C. The origin of species.
Oxford Text Archive, Oxford University Computing Services, [email protected]
ELDREDGE,
N. Reinventing Darwin. Nova York,
Wiley, 1995, p. 95.
FREELAND,
S. J. & HURST, L. D. The genetic code is one in a million. Journal of molecular evolution, 47:
238-248, 1998.
FUTUYAMA, D. J. Biologia
evolutiva. 2nd ed. Ribeirão Preto, Sociedade Brasileira de Genética, 1993.
GARDNER,
E. J., SIMMONS, M. J. & SNUSTAD, D. P. Principles
of genetics. 8th ed. New York, John Wiley & Sons, 1991.
GIBSON,
L. J. A Christian approach to Biology. Christ
in the classroom, 11: 247-254, 1993.
GOULD,
S. J. Wonderful life. New York, W. W. Norton,1989.
GRIFFITHS,
A. J. F., MILLER, J. H., SUZUKI, D. T., LEWONTIN, R. C. & GELBART, W. M. An introduction to genetic analysis.
7th ed. New York, W. H. Freeman, 2000.
McAlester, A. L. História geológica da vida. São Paulo,
Editora Edgard Blücher, 1971.
MORRIS, H. M. O enigma das origens: a resposta. Belo
Horizonte, Editora Origens, 1995.
REPETSKI,
J. E. A fish from the Upper Cambrian of North America. Science, 200:
529-531, 1978.
ROMER, A. S. Vertebrate
paleontology. Chicago, University of Chicago Press, 1966.
ROTH,
A. Origins: linking science and
scripture. Hagerstown, Review and Herald Publishing Association, 1998.
RUPPERT,
E. E. & BARNES, R. D. Invertebrate
zoology. 6th ed. Fort Worth, Saunders College Publishing, 1994.
SEILACHER,
A. Late Precambrian metazoa: preservational or real extinctions? In H. D.
Holland and A. F. Trendall, eds. Patterns of change in earth evolution
(p. 159-168). Berlin, Springer-Verlag, 1984.
SHARP, D. G.
Interdependência na síntese de macromoléculas: evidências de planejamento. Folha criacionista, 19:
47-62, 1978.
STORER,
T. I., USINGER, R. L., STEBBINS. R. C. & NYBAKKEN, J. W. Zoologia geral. 6th ed.
São Paulo, Companhia Editora Nacional, 1991.
WEBSTER,
C. L. A scientist's perspective on
creation and the flood. Loma Linda, Geoscience Research Intitute, 1995.
WISE,
K. The origin of life's major groups. In J. P. Moreland, ed., The creation
hypothesis (p. 211-234). Downers Grove, IL, InterVarsity Press, 1994.
WHITE,
E. G. Testemonies Vol 8.