Origin by Random Chance or Master Plan? A Discussion of Homology
|Author: Eric Blievernicht
Besides the fossil record and natural selection, one other major argument is advanced by advocates of the theory of evolution; the patterns of similarities found in nature. In other words, while the fossil record was supposed to show how evolution proceeded in the past, the similarities and differences between living organisms were supposed to show which living species are most closely related to one another. By comparing the similarities between species, evolutionists can arrange them in evolutionary trees showing their alleged relationship to one another.
In recent years the study of similarities between species has included studies of DNA and molecular biology; the impact of these studies on the creation/evolution conflict is detailed elsewhere. (For two excellent non-creationist attacks on evolutionary theory because of this data, see Michael Behe’s Darwin’s Black Box and Michael Denton’s Evolution: A Theory in Crisis) This paper deals solely with the large-scale structures of living organisms (morphology).
It should be apparent immediately that evolutionists are guilty of circular reasoning if they first assume evolution has occured, then interpret morphological structures in terms of evolution, and then turn around and use these interpretations as “evidence” for evolution. Nonetheless, who has the better explanation for the patterns of similarity and difference found in nature?
The study of similar structures among different species, such as the arm of a man and foreleg of a bear, is known as homology. That homology is not the triumphant proof of evolution it is usually claimed to be is indicated by the title of a book by evolutionist Sir Gavin de Beer: “Homology: An Unsolved Problem.” (1)
Nevertheless, the evidence of similarities in nature has been held as powerful evidence for evolution and against creation. Charles Darwin wrote:
“We have seen that the members of the same class, independently of their habits of life, resemble each other in the general plan of their organization. This resemblance is often expressed by the term “unity of type”; or by saying that the several parts and organs in the different species of the class are homologous. The whole subject is included under the general term of Morphology. This is one of the most interesting departments of natural history, and may almost be said to be its very soul. What can be more curious than that the hand of a man, formed for grasping, that of a mole for digging, the leg of the horse, the paddle of the porpoise, and the wing of the bat should all be constructed on the same pattern, and should include similar bones, in the same relative positions? How curious it is, to give a subordinate though striking instance, that the hind-feet of the kangaroo, which are so well fitted for bounding over the open plains, – those of the climbing, leaf eating koala, equally well fitted for grasping the branches of trees, – those of the ground-dwelling, insect or root-eating bandicoots, – and those of some other Australian marsupials, – should all be constructed on the same extraordinary type, namely with the bones of the second and third digits extremely slender and enveloped within the same skin, so that they appear like a single toe furnished with two claws. Notwithstanding this similarity of pattern, it is obvious that the hind feet of these several animals are used for as widely different purposes as it is possible to conceive. The case is rendered all the more striking by the American oppossums, which follow nearly the same habits of life as some of their Australian relatives, having feet constructed on the ordinary plan. Professor Flower, from whom these statements are taken, remarks in conclusion: “We may call this conformity of type, without getting much nearer to an explanation of the phenomenon”; and he then adds “but is it not powerfully suggestive of true relationship, of inheritance from a common ancestor?” (2)
Darwin apparently felt this was such strong evidence for evolution that he ridiculed his opponents:
“Nothing can be more hopeless than to attempt to explain this similarity of pattern in members of the same class, by the utility or by the doctrine of final causes. The hopelessness of the attempt has been expressly admitted by Owen in his most interesting work on the ‘Nature of Limbs’. On the ordinary view of the independent creation of each being, we can only say that so it is: – that it has pleased the Creator to construct all the animals and plants in each great class on a uniform plan: but this is not a scientific explanation.” (3)
Speaking from Darwin’s perspective, evolutionist and molecular biologist Dr. Michael Denton notes, “Why should a creator be restricted to the same basic pentadactyl design in designing the flipper of a whale or the wing of a flying reptile?” (4) It is unfortunate Mr. Darwin was not an engineer, or he would not have been so foolish.
Take, for example, the automotive industry. This author is the inspector at an automotive packaging and kitting plant which works with Ford, Chrysler, and General Motors on a tremendous variety of automotive parts. Obviously all of the parts with which we work are intelligently designed, not evolved! Yet I continually note similarities between parts, in patterns identical to those found in living species.
One could pick any automobile part – moldings, or dip sticks, or pistons, or carpet retainers, or exhaust pipes, mufflers, engines, wheels, windows, and on and on and on – and find that they exhibit the same patterns of similarity between models of automobiles as are found among living organisms. In other words, no one would consider it strange to discover that the dip stick in a Ford Escort shares many similar features with the dip stick of a Cadillac – yet these were probably not even designed by the same designer, albeit both designers utilized intelligence in their design. How much more so should we expect to find similarities in life if it is the product of a single supremely intelligent designer?
But why, in Dr. Denton’s words, should this designer restrict himself to a single plan? This objection indicates an ignorance of the facts of nature with which all engineers must deal. When I studied engineering at the University of Michigan and Michigan State University, I commonly found that the solution to one engineering problem was the best solution to a wide variety of engineering tasks, with only minor variations. If you were being created right now by the Designer, would you want to have second-rate designs used on your body parts just because the best designs had already been taken?
Or, put another way, why should an intelligent designer be forced to use wildly divergent design solutions with no similarity to one another, just to fulfill the straw man arguments of evolutionists? At best this would simply add unneeded complexity and greater inefficiency to the sub-standard result.
My own father is a professor who teaches biomechanics at Wayne State University, and I grew up learning from him (and his textbooks) about the application of engineering design and kinetics to living bodies. Given that the patterns of similarity and divergence in living forms is closely analogous to the patterns found between different models of computers, or automobiles, or even tableware, all of which are clearly intelligently designed, what is wrong with an argument by analogy that life forms must also be intelligently designed?
The first book by a creationist I ever read noted:
“The creationist believes that such similiarities actually result from the fact that creation is based on the master plan of the great Designer. Where *similar functions* were required, God used *similar structures*, merely modifying these structures to meet the individual requirements of each organism… Far from providing “clear proof” of evolution, the common patterns of design point just as well to common origin from the one Architect or Designer.” (5)
To those who resist the reasonableness of the analogy, he argues:
“It is nonsense to suppose that because the Creator had once used a good plan, he must never again utilize it in creating other animals with this plan only slightly modified. Must every kind of creature be so completely different from all others that we can detect no resemblance between any two? Inevitably, then, as we survey the wonderful variety of living things, we will find similarities.” (6)
Biologist Dr. Gary Parker writes:
“Using descent from a common ancestor to explain similarities is probably the most logical and appealing idea that evolutionists have. Isaac Asimov, (7) well known science fiction writer, is so pleased with the idea that he says our ability to classify plants and animals on a groups-within-groups heirarchical basis virtually forces scientists to treat evolution as a “fact.” In his enthusiasm, Asimov apparently forgot that we can classify kitchen utensils on a groups-within-groups basis, but that hardly forces anyone to believe that knives evolved into spoons, spoons into forks, or saucers into cups and plates.” (8)
That homologies make sense according to the creation model at least as well as the evolutionary model is admitted by no less than Dr. Stephen Jay Gould, perhaps the foremost American evolutionist. (9) But is this true? Can evolutionists really make sense of the morphological data as well as proponents of common design?
For example, evolutionists are agreed that the two major divisions of mammals are the marsupials and placental mammals, and that each has evolved separately. Yet there are many astonishing examples of “pairs” of marsupial and placental mammals that are almost identical to one another.
“According to Darwinian theory, the pattern for wolves, cats, squirrels, ground hogs, anteaters, moles, and mice each evolved twice: once in placental mammals and again, totally independently, in marsupials. This amounts to the astonishing claim that a random, undirected process of mutation and natural selection somehow hit upon identical features several times in widely separated organisms.” (10)
The eyes of an octopus and human are another well-known example. Could random natural selection keep hitting upon the same solution in terribly complex structures, or is an intelligent designer using the same blueprint where it is appropriate a better answer?
According to the theory of evolution, homologous structures grow from similar embryological structures, and are based on minor variations in the same genes of different organisms. (11) In other words, as one species diverged into separate species, the slight differences between, say, the foreleg of one species and the other species would be reflected by a slight difference in the same genes in the same place on the chromosomes of the two species.
This prediction is absolutely wrong, as shown in the monograph by Sir Gavin. (12) As biochemist Dr. Duane Gish noted in a creation/evolution debate, “It has been found, in fact, that the genes governing homologous structures in different animals are totally different.” (13) Biologist Dr. Gary Parker writes:
“Worse yet, for evolution, structures that appear homologous often develop under the control of genes that are not homologous. In such cases, the thesis that similar structures developed from genes modified during evolutionary descent is precisely falsified.” (14)
Evolutionist William Fix explains:
“The older text-books on evolution make much of the idea of homology, pointing out the obvious resemblances between the skeletons of the limbs of different animals. Thus the “pentadactyl” limb pattern is found in the arm of a man, the wing of a bird, and the flipper of a whale, and this is held to indicate their common origin. Now if these various structures were transmitted by the same gene-complex, varied from time to time by mutations and acted upon by natural selection, the theory would make good sense. Unfortunately this is not the case. Homologous organs are now known to be produced by totally different gene complexes in the different species. The concept of homology in terms of similar genes handed on from a common ancestor has broken down…” (15)
In his chapter, “The Failure of Homology,” Dr. Denton discusses many examples that defy explanation according to evolutionary theory. (16) He also warns the those examples which do fit evolutionary theory are illusory. Recalling his comment given above, he writes:
“We have seen that the forelimbs of all terrestrial vertebrates are constructed according to the same pentadactyl design, and this is attributed by evolutionary biologists as showing that all have been derived from a common ancestral source. But the hindlimbs of all vertebrates also conform to the pentadactyl pattern and are strikingly similar to the forelimbs in bone structure and in their detailed embryological development. Yet no evolutionist claims that the hindlimb evolved from the forelimb, or that hindlimbs and forelimbs evolved from a common source.” (17)
“Invariably, as biological knowledge has grown, common genealogy as an explanation for similarity has tended to grow more tenuous. Clearly, such a trend carried to the extreme would hold calamitous consequences for evolution, as homologous resemblance is the very raison d’etre of evolution theory… Darwin’s jibe at Owen now seems increasingly hollow… Like so much of the other circumstantial “evidence” for evolution, that drawn from homology is not convincing because it entails too many anomalies, too many counter-instances, far too many phenomena which simply do not fit easily into the orthodox picture.” (18)
In science, an explanation that does not fit all the known facts is false. A theory that the earth is flat fits some facts! Thus, “proof” of evolution by homology falls on its face, and there seems little chance the evolutionary explanation can be revived.
As Dr. Parker explains, similar structures are simply not distributed in a pattern according to evolutionary descent. Instead, they are distributed in a “mosaic” pattern, missing from some organisms that evolutionists would expect to have them, and being found on other organisms that should not have them according to evolutionary theory:
“One of the students I taught, for example, had a passion for lizard ear bones. He came in late in the evening and early in the morning – always dissecting lizard ear bones, sectioning, and so on. That got him interested in lizards in general. But he noted that in attempts to classify lizards, one fellow would go on the field characteristics and he’d come up with one system. Another fellow would go by the bone patterns and he’d come up with another system. Internal organs suggested a third, and so on. The pattern is not a branching one suggesting evolutionary descent from a common ancestor; rather, it is a mosaic or modular pattern suggesting creation.” (19)
Finally, Dr. Dean Kenyon and Percival Davis conclude:
“What such examples reveal is that similarities do not trace a simple branching pattern suggestive of evolutionary (genealogical) descent. Instead they occur in a complex mosaic or modular pattern. Similar structures, like the hemoglobin molecule, appear here and there in the mosaic of living things, like a silver thread weaving in and out of a tapestry. Similarities may also be described as fixed patterns or discrete blocks that can be assembled in various patterns, not unlike subroutines in a computer program. Genetic programs each incorporate a different application of these subroutines, generating the diversity of biological forms we see today.” (20)
This concept of genetic programming was first advanced in 1983 by Tom Pittman. (21) “He suggested that the Designer coded for the number and position of bones in all vertebrate animals by means of one basic DNA code package.” (22)
Pittman describes his object-oriented programming (OOP) hypothesis as follows:
“This then is the prediction from design: when the genetic codes are unraveled for the larger organisms, the creationist would expect to see tightly-coded packages of genetic codes which are responsible for entire structures in the organism. There will be no rational or obvious relationship between components of the code and the components of the structure defined by it: skeletons will not be defined by the aggregate of the codes for the individual bones.
The prediction of descent with modification, as Awbrey calls his version of evolution, would be to find primitive genetic patterns with perhaps a few bits modified, and various random accumulation of codes, each of which defines one specific component of the resulting organism, or is perhaps kept on as “baggage” and supressed by other specific patterns.
The difference between these two predictions should be clear. Both “explain” the so-called vestigial organs, and the explanations are similar. But the differences are testable, and should be as apparent to the trained observer as the difference between a well-designed,optimized, program and a hodgepodge of sundry sub-routines loosely stuck together by a bunch of incompetent hackers.” (23)
We do not as yet have sufficient knowledge to conclusively choose one side or the other, though Denton’s book (24) lends support to the programming/design hypothesis. It would seem that the creationist paradigm is gaining steady superiority over the evolutionary paradigm in explaining the patterns of morphology found in nature.
1. de Beer, Sir Gavin, Homology: An Unsolved Problem (London: Oxford University Press, 1971).
2. Darwin, Charles, The Origin of Species (New York: Collier Books, 1962), p. 434-435.
3. Ibid, p. 435.
4. Denton, Michael, Evolution: A Theory in Crisis (Bethesda, MA: Adler & Adler, 1985), p. 144.
5. Peth, Howard, Blind Faith: Evolution Exposed (Frederick, MA: Amazing Facts, 1990), pp. 58-59.
6. Ibid, p. 59.
7. Asimov, Isaac & Duane Gish, “The Genesis War,” Science Digest, October 1981.
8. Parker, Gary & Henry Morris, What is Creation Science? (El Cajon, CA: Master Books, 1987), p. 54.
9. Gould, S.J., Natural History, January 1987, p. 14.
10. Kenyon, Dean & Percical Davis, Of Pandas and People: The Central Question of Biological Origins (Dallas: Haughton Publishing, 1993), p. 33.
11. See “Gill Slits” paper, or virtually any general text from a creationist perspective, such as Ian Taylor’s In the Minds of Men (Toronto: TFE, 1992).
12. Ref. 1.
13. Morris, Henry & Donald Rohrer, The Decade of Creation (San Diego: Creation-Life Publishers, 1981), p. 196.
14. Ref. 8, p. 55.
15. Fix, William, The Bone Peddlers: Selling Evolution (New York: Macmillan Publishing Co., 1984), p. 189.
16. Ref. 4, pp. 142-156.
17. Ibid, p. 151.
18. Ibid, p. 154.
19. Ref. 8, p. 55-56.
20. Ref. 10, p. 33.
21. Pittman, Tom, “Coding Theory and “Vestigial” Organs: A Testable Prediction from Design,” Origins Research 6(2):3 ff.
22. Bergman, Jerry & George Howe, “Vestigial Organs” Are Fully Functional, CRS Technical Monograph #4 (Terre Haute, IN: Creation Research Society Books, 1990), p. 23.
23. Ref. 21.
24. Ref. 4. For example, on p. 336, Dr. Denton describes an extraordinary information compression technique used by DNA, years before primitive compression techniques became widespread in computer software. “Overlapping genes are not the only recently discovered ingenious device for compacting information with great economy into DNA sequences…”
Eric J. Blievernicht c1994, 1996.