Part IV: The Fitness of Living Beings and the Significance of Dauermodifications
Chapter 1
THOSE WHO live nearest to nature never cease to wonder at the fitness of living things. Until man intrudes, nature seems replete with evidences of wise design. Every creature is equipped with all the structures, all the skills, and all the instincts necessary for its own continuance as part of the web of life. Man alone appears to be an alien and a disturber.
The concept of nature as "red in tooth and claw," which Tennyson introduced in his poem In Memoriam some ten years before Darwin published his Origin of Species, is increasingly being viewed today as a travesty of the natural order. Probably the only reason it has survived so long is that those who contributed most to reinforce it by their writings, including Darwin himself, derived too much of their knowledge of animal behavior by observing them in captivity. In the wild there is inevitably some shedding of blood, but we now know that cruelty per se is almost entirely absent. Death is avoided by all living things, and they do not seem to live in fear of death, except where man intrudes.
Structurally animals are extraordinarily sensitively fitted for the kind of lives they live. To the Christian this is evidence of wise design, but to the unbeliever it seems to demand some other explanation. In many cases where the element of fitness is truly extraordinary, it becomes extremely difficult to see how it could come about purely by chance.
One of the earlier students of nature who sought to account for this fitness without any direct appeal to supernatural intervention was Jean Baptiste Lamarck (1744 - 1829). In his Philosophie zoologique, published in 1809, he reasoned that any animal could adjust itself structurally to improve its fit with the environment and pass on the advantageous adjustment to its descendants. By a process akin to compound interest, each generation improved upon the fitness of the previous one and thus all living creatures constantly enhanced their chances of survival---not by a process of elimination of the unfit, but by improving their own fitness. This natural ability was resident within the constitution of all living things. It was not a conscious goal-seeking which might be confused with some form of teleology, but simply part of the stuff of living. The important thing was that every gain was inherited. "Lamarckianism" came to be defined simply as "the inheritance of acquired characteristics," and the acquired characteristics were modifications of structure resulting to the benefit of the organism from the direct influence of the environment.
In Darwin's time, Lamarckianism was very widely accepted by those who by disposition sought an explanation of fitness without appeal to supernatural agency. Curiously, Darwin did not himself feel happy about it. He sought for and found what he considered a better explanation in the multiple concepts of Natural Selection, the Struggle to Survive, and the Survival of the Fittest. In Darwin's view, Lamarckianism was unrealistic, mystical, and not adequately borne out by the facts. He saw the elimination of the unfit as a much more likely and verifiable principle of improvement of a species. He did not reject the inheritance of acquired characteristics, but he questioned whether characteristics were ever acquired by the mechanism Lamarck envisioned.
In the course of time, however, Darwin himself gradually shifted his position in this respect, and it is interesting to observe the change in his thinking as reflected in his own written observations. In 1861 he wrote: (1)
My greatest trouble is not being able to weigh the direct effects of the long continued action of changed conditions of life without any selection, against the action of selection on mere accidental (so to speak) variability. I oscillate much on this head, but generally return to my belief that the direct action of the conditions of life has not been great. At least this direct action can have played an extremely small part in producing all the numberless and beautiful adaptations in every living creature.
But one year later, on 24 November 1862, Darwin wrote to Sir Joseph D. Hooker: (2)
I hardly know why I am a little sorry, but my present work is leading me to believe rather more in the direct action of physical conditions. I presume I regret it because it lessens the glory of Natural Selection and is so confoundedly doubtful.
Darwin reflected upon the matter and became convinced enough that ten years later, when he published the sixth edition of his Origin of Species he observed: (3)
Species have been modified...chiefly through natural selection of numerous, successive, slight, favourable variations, aided in an important manner by the inherited effects of use and disuse of parts; and in an unimportant manner...by the direct action of external conditions...It appears that I underrated the frequency of these latter forms of variation as leading to permanent modifications of structure independently of natural selection.
In the first edition of his Origin of Species (1859, chap. 6, p. 256), Darwin had said that natural selection is "in some cases" aided by the use and disuse of parts and "slightly affected" by the direct influence of the environment. In the sixth edition (1872, p. 167) the words "in some cases" had become "in many cases," and "slightly affected" had become simply "affected." Four years later, in 1876, Darwin wrote in a letter to Moritz Wagner: (4)
In my opinion the greatest error which I have committed has been not allowing sufficient weight to the direct action of the environment, i.e., food, climate, etc., independently of natural selection...When I wrote the origin and for some years afterwards I could find little good evidence of the direct action of the environment; now there is a large body of evidence.
Finally, in 1877, in a letter to Melchoir Neumayer dated 9 March, he wrote concerning an example of direct influence of the environment reported by his correspondent. (5)
It is by far the best case which I have ever met with showing the direct influence of life on the organism.
But his common-sense logic and the evidence he accumulated in support of natural selection were persuasive enough that they prepared the way for the final overthrow of Lamarckianism---an overthrow completed by the experiments of Auguste Weismann (1843 - 1914).
It had long been recognized that modification of a parent body by artificial means had no effect upon the offspring. Circumcision, for example, had been practiced for thousands of years without leading to a race of congenitally circumcised male children. The operation still had to be performed in every generation. Still there was a possibility that the modification was not effectively passed on because only the father of the next generation was involved, and not the mother. If some comparable gross modification of the mother had been repeated over the same period of time, the results might have been different. However, it had been customary in China for many centuries to bind the feet of female infants in the upper classes of society. Small feet were considered beautiful. Yet here again there was no evidence that the modification was becoming inheritable. Clearly, modifying the male or the female in such ways, even after centuries of repetition, did not affect the germinal stream in any way, since no influence upon subsequent generations had ever been observed.
In an attempt to determine whether inheritance of such modifications or acquired characters would occur if both sexes were modified in the same way, Weismann cut off the tails of experimental mice of both sexes, male and female, for many generations: he still found that such a modification did not become inheritable. Thus Julian Huxley remarked upon the apparent immunity of living organisms against all experimental attempts to modify their characteristic form in a way that would be self-perpetuating, underscoring the fact that there seems to be no direct effect of the environment upon the germ plasm. In 1938 Huxley observed, (6)
Can the hereditary constituents be permanently changed by environment? It is clear that theoretically it should be possible to induce such changes. The hereditary constitution is seen to be something material which only our lack of knowledge prevents us from defining chemically; and as such it must be pessimistic for us to alter it. The remarkable fact, however, is its stubbornness in resistance in alteration.
Sixty-nine generations of flies bred in the dark--and yet no alteration in their eyes or their instincts with regard to light. Ninety generations in an attempt to cause their resistance to heat by acclimatization and selection without result....
In spite of all the work that has been done, we have only established that to a great many apparent outward influences the germ plasm is quite unresponsive.
Admittedly this was written four decades ago, but subsequent research has only reinforced the conclusion. Insofar as the germ plasm and nuclear genes are concerned, the results are still negative. No experimental modification of the body cells seems capable of bringing about inheritable changes in the nuclear genes of the organism. As some wag is reported to have said when referring to the negative results of Weismann's experiments, and with apologies to Shakespeare's Hamlet: "There is a divinity that shapes our ends, rough-hew them how we will."
Now it is possible by deliberately damaging the nuclear genes to bring about inheritable modifications. But this kind of interruption of the normal development of an organism must be a comparatively rare event in nature, (7) and when it does occur it is even less likely that the effect will be beneficial. Indeed, there are many geneticists who believe that all gene mutations which result from this kind of interference with the normal development of the organism are harmful. Individuals carrying such harmful genes would tend to be eliminated in the natural course of events, simply because they are less fit.
The amazing fitness of organisms within their own particular habitat demands an explanation. And the explanation must also account for the fact that living things seem to have a large capacity for adjustment to environmental pressures and seem to be able to pass on the benefit of these adjustments by inheritance to succeeding generations. Since experimentally it has not seemed possible to mimic nature in this respect by effecting changes on nuclear genes we must suppose either that there is some built-in mechanism of adjustment that is inheritable by some other means than nuclear genes, or that God has been at work creatively making these adjustments throughout the past.
Certainly the fitness of things is everywhere manifest in nature and all the more manifest as the circumstances are more carefully examined. Since the environment tends to be in a state of flux, fitness must involve a similar flexibility. The ideal mechanism would be one which can capture and hold any successful adjustment made in one generation so that the next generation can build upon it. Wood Jones was one of those who argued strongly for this view, but despite his eloquence, current orthodoxy---having rejected Lamarck---did not allow him a hearing: he was arguing in favor of some form of inheritance of acquired characters. (8) He was arguing, in fact, in favor of the view that environmental pressures did have a direct effect on the development of living forms over successive generations and not merely an indirect effect through a process of natural selection by elimination of the less fit.
The negative evidence against the inheritance of acquired characters under experimental conditions in the laboratory is not always borne out by what goes on in nature. The contradiction may have been unresolved in the past, because current theory has demanded that nuclear genes provide the only pathway for inheritable factors and these genes are remarkably immune to the direct influence of environmental pressures, except those which are essentially damaging.
But in the past few years a renewed interest in the possibility of another pathway whereby the environment might have a direct influence upon an organism responding in an inheritable way has led to the conclusion that there are probably carriers of inheritable material in the cytoplasm of the cell and not merely in the nucleus. These carriers, which have been termed Plasmagenes, are responsive to the direct action of the environment. This responsiveness appears to be somewhat delayed, so that the environmental pressure must be held constant over several generations to influence the plasmagenes. That the response of these extra-nuclear genes can be inherited through succeeding generations is demonstrated by the fact that the effect persists even when the original stimulus is removed. If the environment gradually reverts to its original nature, the modified organisms will continue to retain their altered form for several generations, and then they too revert.
Thus the response of the organism to direct environmental pressure is demonstrated. Yet it is seen to be of such a nature that it retains its flexibility and is therefore able to adjust in either direction to its own advantage and pass on the adjustment to successive generations. In this way the mechanism contributes to the fitness of the organism without endangering it if the environmental pressure changes. This type of modification which continues for a limited time even when the stimulus which provoked it is removed has been termed a dauermodification.
Such a mechanism serves the dual purpose of preserving the line in its purity and maintaining the species as such, while at the same time opening the way for a form of adjustment that allows a particular species to spread successfully into different habitats which it could not otherwise occupy. The nuclear genes therefore preserve the species as such: the plasmagenes preserve the local population as a variety.
The difference between the conventional Darwinian view of natural selection and the view which is now beginning to crystallize, based on plasmagenic inheritance of acquired modifications, is this: the former depended upon a process of selective elimination of the unfit, whereas the latter favors survival by inherited adaptation. Progress, identified as increasingly successful adaptation, no longer becomes a ruthless weeding out, but a demonstration of a sensitive mechanism specifically designed to guarantee exactly the opposite result, namely, an improvement in the chances of survival of every individual. It is in some sense a reflection of the benevolence of the Creator rather than of a pitiless eradication in the interests of efficiency at all costs.
The older view of nature as ruthlessly efficient is therefore replaced by a more generous view, which holds that any disadvantaged species need not be eliminated but is provided with the means of contributing to the greater fitness of its descendants. This is achieved by passing on to these future generations the benefits of its own response to the environment even though these were not overtly expressed in its members at the time.
It is as though the Lord has so designed the mechanism of inheritance in order that the "kinds" of Genesis will not be destroyed or blurred, while yet allowing modification which greatly increases the range of climate, altitude, food resources, and so forth, that the particular species can occupy. There are numerous illustrations of this type of response among plants and animals; and there are some striking illustrations of it for man himself.
Chapter 2
THE TERM dauermodifications (original German: dauermodificaationen) seems to have been first used by V. Jollos in 1913. (9) It has still not found its way into evolutionary literature in general, because the climate of opinion is not sufficiently favorable toward the concept for which it stands. Yet the phenomena which it was coined to define have been observed and demonstrated experimentally for many years. Dauermodifications are the kind of modifications which are observed in living things in response to environmental pressures and which, when they occur in one generation, appear to be inherited by the next.
Jollos originated the term to describe what he observed to be long-lasting changes induced in paramecia by heat treatment and by various chemicals, which he was persuaded were being transmitted through the cytoplasm rather than the nucleus. Moreover, he noted that such induced changes, or "modifications," continued to be propagated over successive generations even after the inducing agent had been removed.
In a textbook on organic evolution in 1952, A. W. Lindsey reported experiments by F. B. Sumner and others, reinforcing the evidence for cytoplasmic inheritance of this kind. (10) Sumner raised white mice at 20-30 degrees C. and found that at the higher temperatures they developed longer bodies, tails, ears, and hind feet. In these experiments Sumner took normal mice and exposed them to an environmental pressure in the form of a higher temperature than they were accustomed to; he discovered that within a few generations the mice had modified their bodies to improve their chances of survival by increasing the amount of body surface area from which heat could be radiated. This included elongation of the body, enlarging the ears and tail (both of which are excellent heat exchangers), and also enlarging the hind feet for reasons which are not altogether clear at the moment. These modified animals were then returned to a normal environment and mated. Their offspring were raised at temperatures normal to the species. It was found that these offspring retained the modified form for some generations even though they were no longer being subjected to above-normal temperatures.
Thus Sumner demonstrated experimentally that the modified form had become inherited. He also demonstrated that with a return to a normal environment, the inherited modification only gradually reverted to original type. This seemed to be clear evidence that the elongated shape which was an acquired character in response to heat had indeed become inherited, but only in a semipermanent way. Sumner was convinced that this was a form of cytoplasmic inheritance, since it had been demonstrated so clearly by others that the nuclear genes are not subject to environmental influences.
That the cytoplasm was capable of influencing the form and function of daughter cells had already been argued by a number of developmental physiologists and embryologists on the following grounds. Since all cells in an organism share the same nucleus and yet differentiate specifically into different kinds of tissue---bone, tendon, nerve, muscle, skin, and so forth---the power of differentiation was presumed to be under the control of the cytoplasm rather than the nucleus. Moreover, since millions of cells retain their ability to produce any one of these specifically different structures in the body, there must be some inheritable factors unique to the controlling cytoplasm which governs the proliferation of cell lines in certain directions. Boris Ephrussi put it succinctly: (11)
Unless development involves a rather unlikely process of orderly and directed gene mutation, the differential must have its seat in the cytoplasm.
If the cytoplasm causes differentiation, it must be endowed with the power of perpetuation of cell type.
Bone cells continue to reproduce bone and not skin---not because their nuclei are different from cells producing skin, but because their proliferation as bone cells is under some cytoplasmic control which so directs them. Since these cells replicate as bone and not as, say, muscle, the control must be passed on from cytoplasm to cytoplasm by some process of inheritance. We seem therefore to be driven to the conclusion that there is a cytoplasmic form of inheritance as well as a nuclear gene form of inheritance, and it seems likely to be of a somewhat similar particulate nature.
Certain experimental difficulties continued for many years to leave the matter in doubt, especially by contrast with the easily demonstrable and therefore undoubted hereditary factors in the nucleus. Lindsey complained that the experimental evidence of cytoplasmic inheritance existing by 1952 was ignored by most geneticists because of their anti-Lamarckian bias. It was simply denied that any environmental pressure could influence the nuclear genes, which were held to be the sole determiners of inheritable characters.
In 1953 Boris Ephrussi published a report of his work with paramecia in such a lucid manner as to draw fresh attention to the evidence of cytoplasmic inheritance. He wrote: (12)
These studies confirm the view that cytoplasm, like the genes, is endowed with genetic continuity. The genes are therefore no longer to be regarded as the sole cell-constituent with this property.
Ephrussi's book is a delight to read. He is full of enthusiasm for his subject, and this enthusiasm is communicated to the reader in a flow of language which seems easily to be able to handle the most complex details. At that period Ephrussi did not seem certain that the mechanism always involved active particles of some kind in the cytoplasm which would be comparable to the genes in the nucleus. But certainly the mechanism of this type of inheritance resided in the cytoplasm and not in the nucleus. Toward the end of his book he wrote: (13)
Considering that embryonic development results in a restriction (and some widening, too) in different cell lineages of the manifold potentialities originally carried by the egg, we may picture the process of differentiation as consisting, for example, in the segregation or sorting out of an initially mixed population of cytoplasmic particles. Or we may suppose that the egg, to begin with, contains a mixed population of inactive particles and that development consists in the activation by nuclear genes of different sorts of lineages.
In 1959 C. L. Prosser was able to report: (14)
Several types of non-genie inheritance and of indirect effects of environmental selection on the genotype are recognized. Cytoplasmic inheritance is being discovered in more and more groups of organisms, and cytoplasm is more readily influenced by the environment than is the nucleus.
Now, the ovum in many species, including man, is much larger than the spermatozoon. In man the ratio is about 500 to 1 Since the nucleus is of equal size in both, the difference in mass results from the far greater amount of cytoplasm which the ovum contains.
It is considered that this fact is related to the greater importance (in some matings) of the female contribution rather than that of the male, and it results in such instances in a greater resemblance of the offspring to the female parent. This in itself reinforces the likelihood that some real contribution to inherited factors is made specifically by the cytoplasm. In his book on the architecture of the cell, Verne Grant proposes that if a cytoplasmically controlled character does not persist for more than a generation or two, it could be explained as a maternal effect in which the nuclear genes of the mother, by imposing some condition on the cytoplasm of the egg, predetermines a phenotypic trait of the offspring. The trait in question is not therefore carried by some particles in the cytoplasm acting autonomously.
On the other hand, if the cytoplasmically controlled characteristic persists for several generations but still eventually disappears, it should be regarded as a dauermodification. The decisive test is persistence for a number of generations even when the stimulus which was the determining factor is removed. As Verne Grant observed: (15)
We are forced to conclude that particles with a gene-like property of self-reproduction exist in the cytoplasm. Inheritance through the cytoplasm has been verified for a number of plants, animals, protista, and fungi.
A little later Grant refers to a plant experiment undertaken by P. Michaelis (16) in which enucleated cells retaining only the original cytoplasm were supplied with nuclei from other cells. These structurally modified cells were then cultured, and it was demonstrated that "the cytoplasmic constituents responsible for the characters in question maintain their identity and produce their specific action even though under the influence of a foreign nucleus for 24 generations." (17) This would seem to indicate that the hereditary factors in the cytoplasm do, in some cases, have genuine autonomy. Grant was writing in 1964. Since that time the principles of cytoplasmic inheritance have been elaborated somewhat, as may be seen from Alfred Kuhn's treatment of the subject.
Alfred Kuhn published his lectures on developmental physiology in 1971. He observed: (18)
The form and size of [certain protozoans] can be modified strongly and in various ways by environmental factors. Certain modifications of form are retained as dauermodifications for a long time after the conditions change, and it often takes a large number of generations before a new form corresponding to the new conditions is acquired.
And we shall see in the next chapter, the response of the organism to the environment may be extraordinarily rapid, even in man. Toward the end of his volume, Kuhn wrote: (19)
In dauermodifications the consequences of transient environmental influences can last for many cell generations in single-celled organisms and for several individual generations in multi-cellular organisms. The norm of reaction of the cells is in all these cases controlled by alterations of the cytoplasm...In dauermodifications, cytoplasmic components with altered properties must replicate.
Thus, in order to understand the nature of determination one is led to the possibility that certain cytoplasmic structures are capable of self-replication and that their relative numbers and properties can he altered by appropriate conditions. That part of the hereditary mechanism lies in the cytoplasm cannot be doubted.
A cytoplasmic property which shows extra-nuclear inheritance has been called the plasmagene or plasmon by von Wettstein. The name plasmagene has been given to the bearer of properties inherited in an extra-nuclear fashion.
At this point Kuhn lists a number of references to work in this area by E. Caspari (1948 - 55), F. Ochlkers (1952), P. Michaelis (1954), and R. Hagemann (1964).
Thus we come in a kind of circular course from a general acceptance of Lamarck's common-sense doctrine of the inheritance of acquired characters in the early eighteenth century to a position of uncertainty by the mid-nineteenth century, followed by outright rejection in the first half of the twentieth century. And now we are back again to the original position, but on an entirely new basis. As soon as the doctrine began to receive more favorable attention by a few members of the scientific community whose opinion was not to be lightly set aside, then a host of lesser authorities suddenly began to observe any number of potential examples of cytoplasmic inheritance, and a whole new field of experimental inquiry was opened up.
Today there is a wide measure of agreement that organisms have the power to improve their fitness by adjusting their form and function and passing on these adjustments to their offspring. Nuclear genes do not seem to be involved, and for the most part the older established doctrines of nuclear genetics remain valid. Nuclear genes are indeed surprisingly impervious to environmental pressures, but plasmagenes are not. A way is thus opened for any organism to contribute to the greater fitness of its descendants, and the whole of nature is in a position to reinforce the fitness of things without becoming in bondage to an altered form which in a later reversion of the environment would spell its doom.
We shall now examine some of the growing evidence that such a mechanism does exist.
Chapter 3
THERE IS A built-in stability accompanied by a responsiveness to environmental pressures in all living things---plants, animals, and man. This built-in stability guarantees order and therefore a measure of predictability which provides man with the means of controlling the development of things to his own advantage. Responsiveness, on the other hand, fits all these creations of God to their physical world and to one another, to produce a grand harmony. The former is maintained through nuclear inheritance; the latter is achieved through cytoplasmic inheritance.
It has always been obvious enough, really. Naturalists of an older generation with Christian leanings saw in the fitness of things evidence of God's directive providence at work. Evolutionists later came to attribute this fitness entirely to the operation of chance, rejecting the idea of direct intervention of the Creator. Today it seems that we may once again be in a position, on the basis of hard evidence, to recognize a mechanism by which both stability and adjustment are combined to allow a measure of freedom of variation in form and function without inviting a total breakdown of order.
The ability of plants to acquire a new character which enhances fitness, and to pass it on to succeeding generations as long as the environment favors it, has been recognized for many years. It was the transient character of this kind of inheritability that defied explanation in conventional Mendelian terms. Yet it is this transient character which seems so necessary to ensure fitness when environmental conditions change. The environment is changed, not merely when a shift in temperature or humidity occurs, but also when a species is forced to migrate into a new habitat due to the pressure of numbers or other competing forms of life. In either case, from the point of view of a particular species, the environment has changed and it is essential that the species adjust or become less fit to survive.
Julian Huxley many years ago remarked upon the fact that plants are able to make this kind of adjustment when they are transplanted. He noted that dandelions whose natural habitat was lowland country changed their size, form, and proportions surprisingly quickly when transplanted to a higher altitude. (20) But the adjustment was transitory, for if these modified plants were then returned to their former habitat, they quite quickly recovered their previous size and form. This phenomenon is common enough in nature. Since the nuclear genes remain constant, the change in either direction has to be attributed to some factor in the cytoplasm.
The change in such a case is rapid but not always immediate, and the reversion to type follows the same course. Such a circumstance can only be accounted for on the basis of some kind of inheritableness, since it is progressive and carried over cumulatively. Had mutations of nuclear genes been involved, the effect would be instantaneous rather than occupying several generations. Slow adjustment, even if it occupies only two or three generations, clearly indicates a carry-over effect which demands explanation in terms of some inheritable influence. These dandelion observations ought to have suggested non-nuclear inheritance, but the climate of opinion did not allow such a suggestion---or if it was made, it did not gain a serious hearing.
Now, for many years there has tended to be far greater popular interest in animals than in plants, because the theory of evolution has occupied such a large place in our thinking and comparatively few people connect the theory with plant life. The renewed possibility of the inheritance of acquired characters in animals has begun to excite more interest in recent times, because it could provide an alternative to natural selection as the modus operandi of progressive change. An increasing number of authorities are having second thoughts about the adequacy of the concept of natural selection today, and cytoplasmic inheritance would seem to provide a new and exciting alternative.
It often happens that when an idea which has hitherto been repudiated begins to receive more favorable attention, a whole wealth of new evidence in its favor is suddenly discovered. It is certain that a number of authorities whose standing in the scientific community is unchallengeable have for some time been questioning the validity of natural selection as an explanation of the fitness of things. Lucien Cuenot in France, Wood Jones and Sir Alister Hardy in England, W. R. Thompson in Canada, and many others have openly challenged it. (21)
The factors which cause modification tending to greater fitness are observed in animal species at every level of complexity. The pressures which operate to spark these adjustments are of at least three kinds: climatic (which would include environmental temperature, humidity, altitude, wind, etc.); biotic (other living things which exert selective pressures due to predation, crowding, altered breeding habits, etc.); and edaphic (the nature of the rocks and the soil insofar as they influence the types of food available, their varying nutritional character, and the kind of water).
Sir Cyril Hinshelwood has shown that even such lowly forms as bacteria respond to such pressures. (22) Various kinds of bacteria will "learn" to cope with a new food or poison and will transmit their acquired biochemical wisdom more or less durably (according to the number of cell generations for which the treatment has been applied) to their descendants. We are only too well aware of the fact that various insecticides applied to plants---and antibiotics applied to ourselves---tend to lose their potency if they are used in one form for too long a period. The organisms under attack develop an immunity (or fitness, from their point of view) without becoming specifically different at a species level. Only by modifying the treatment every so often can they be held in check by reason of the constant upsetting of the mechanism of adjustment whereby they are able to develop immunity. This is clearly a case of dauermodification.
But it is not merely in these lower forms of life that we observe this phenomenon. We have a number of instances of species of frogs or salamanders which have gradually spread along either side of some natural barrier such as a mountain or a lake and diverged sufficiently as they spread that, when they were again brought into contact at the far end of the barrier, they show themselves to be no longer a naturally interbreeding community. (23) The two populations that demonstrably began as one are now isolates and continue to be so even though sharing a single habitat again. This separateness may stem from several causes, depending upon the particular route taken by the migrating sub-populations. A different food supply along the way may induce different tastes that become inherited and persist. This in turn may cause a divergence in body odor (24) or size or coloration or mating calls or other changes (25) which are preserved by the two divergent lines even after they come together again in a single habitat. The new tastes may in no way affect the fitness of the individual, and there will therefore be no immediate pressure tending to its reversion.
It is clear that such divergent subspecies are still genetically a single species, for it can be shown in many cases that they will interbreed in the laboratory. (26) Yet, for what might be called psychological reasons, (27) they no longer do so in nature. It seems likely that in some instances the single habitat shared by both subspecies will tend to draw them together again; but this does not necessarily happen, since their divergent forms may both be very well-suited to their survival so that there is no pressure driving them toward convergence again. The persistence of the divergent forms under these circumstances is clearly an example of dauermodification. T. M. Sonneborn notes that: (28)
Differing conditions for mating reactivity (temperature, light), once they arise, constitute such effective barriers to interbreeding that different varieties (of protozoa) can and do intimately coexist in the same body of water without losing their integrity. Even when the mating type specificities are only slightly different and interbreeding is possible, the varieties are found to coexist in the same body of water in nature. From these observations, it would seem that even relatively slight changes in mating type specificity could lead to isolation of a new variety.
The opposite of a divergence is convergence. In this case, two distinct species which cannot be shown to have a common ancestry may increasingly become alike in form and function as a result of sharing similar needs under similar environmental conditions. Some of the evidence of this well-established phenomenon is examined in a previous volume in this series. (29) Such a mechanism must also involve the principle of dauermodification; otherwise each generation would have to start from scratch and the offspring would be born without the advantages accruing from their parents' experience. The gains would not be cumulative. But we know that such gains are cumulative, because the neonate is usually found to bear in miniature most of the structures which the adult has acquired to its own advantage. For example, a number of animals which live in and out of water display an alignment of nostrils, ears, and eyes that permits them to submerge themselves almost entirely below the water while yet being able to breathe and see and hear what goes on around them. The hippopotamus and the crocodile are among such animals, and their young are similarly equipped.
F. Wood Jones wrote eloquently about many of these examples of fitness of animals for the kind of lives they live. But unfortunately he attributed it to what can best be described as a kind of mystical goal-seeking drive in all living things directed toward satisfying needs begotten by the circumstances of ecological demands. He commented: (30)
Exactly how these could be explained on the supposition that structural alterations are due solely to random genetic variations acted on by "natural selection" determining the "survival of the fittest" in a "struggle for existence" is a thing which seems very difficult to conceive.
It is a principle broadly applied in the history of the development of scientific ideas that a useful theory is not overthrown by the mere citation of contrary evidence, but only by the presentation of a better theory. Natural selection, rightly or wrongly, is a concept which has much to commend it. It appeals to our sense of the obvious, and in terms of human experience the history of man seems to bear it out. Moreover, it can be made rational justification for the powerful among men to exhibit freely some of the worst aspects of human nature.
But it is not at all certain that animal nature and human nature are the same. What is appropriate in nature may not at all be appropriate in human society, so that neither the reasonableness nor the unreasonableness of the concept of natural selection in human terms has any real bearing on whether it is an appropriate concept to apply in nature. Man is a fallen creature, and his present behavior makes him unnatural by almost every standard of judgment. We do not find the struggle to survive in nature taking the same form as it does in human society. There is no certainty that nature is ruthless in the sense that human society constantly tends to be.
The fitness of things in nature is everywhere apparent. The un-fitness of man is also everywhere apparent. One would suppose that if man is really part and parcel of the web of nature, he will become increasingly fit by the same kind of dauermodifications. There is some evidence that such modifications do indeed improve man's fitness, but there is the disruptive factor of man's fallen nature constantly placing his survival in jeopardy.
As we shall see in the next chapter, man shares in the web of life to the extent that dauermodifications at least contribute this much to his well-being, namely, that he is better able to obey the command to fill the earth and subdue it. It is dauermodifications that have enabled him successfully to become truly ubiquitous. He can thrive in any climate. It is a remarkable fact that wherever dauermodifications can be demonstrated in man, they seem to serve this purpose above all---which may be one more evidence of benevolent design.
Chapter 4
THE HUMAN RACE is known to be a single species, since men and women everywhere in the world freely mate and produce fertile offspring if they are so inclined. Yet there are some remarkable differences in stature and body build, from the diminutive Pygmies of the Ituri Forests in the Congo to the Negro giants of the Upper Nile in Abyssinia. The range in height is from less than four feet to over seven.
Very few, if any, anthropologists today would challenge the assertion that Homo Sapiens is a single species. The divergences in type, therefore, are presumably the result of environmental influences, although some distinguishing characteristics such as hair form, skin and eye color, and supernumerary fingers and toes are probably the consequence of gene mutations. That skin color is not a result of climatic conditions seems to be borne out by the persistence of fairer skin among many peoples living near the Equator, and the persistence of darker skin (often almost black) of many peoples who have for centuries lived nearer the north and south poles.
But we have considerable evidence of dauermodifications of various kinds in man in certain regions of the world where environmental pressures are extreme. Two particularly notable examples have already been mentioned---the forest Pygmies and the Nilotic Negro giants. Both varieties of the human species have almost certainly arisen as the result of a combination of high temperature and high humidity throughout most of the year.
The human body must operate without overheating. We are so constructed that we can sustain a remarkable fall in body temperature; but a rise above normal (98.60 F.) of only a few degrees can rather quickly prove fatal.
The body has a series of defenses against a fall in temperature. The first defense is usually a change in the character of peripheral blood circulation during which the smaller capillaries and venules are closed off and the blood is channeled to circulate at a deeper level and not at the skin surface, where its heat would be lost by conduction or radiation. This is known technically as vasoconstriction. The skin accordingly turns whiter, and numbness is experienced at the extremities due to the loss of circulating blood at the nerve endings. If this initial defense mechanism fails to conserve heat adequately and deep body temperature continues to fall, certain muscles are automatically tightened in such a way that metabolic activity---and with this, metabolic heat---is increased. Some of these surface muscles erect skin hairs as a consequence, causing the familiar phenomenon of "gooseflesh." The nerve impulses to the muscle fibers, which cause the fibers to contract, are fired at random so that the overall effect is a generalized increase in muscle tone. When one returns to the warm, the sudden sense of release and relaxation is a pleasant experience.
If this second defense mechanism still proves insufficient, the nerve impulses are no longer fired randomly but are suddenly coordinated into rhythmic contractions. Firing in unison, they produce shivering. The first form of general muscle tension in the cold can increase metabolic heat production by as much as 100 percent; shivering can increase it by 300 percent! One should not try to suppress it: it is a powerful mechanism for the maintenance of deep body temperature and the preservation of life itself.
Now, in the heat there is a somewhat analogous series of mechanisms. The first is a sudden opening up of peripheral blood vessels, called vasodilatation. As vasoconstriction causes whitening of the skin so vasodilatation causes reddening. Alcohol is a vasodilator, and the characteristic reddening of the skin which accompanies excessive drinking is a demonstration of this. The deep body heat which has begun to increase is now conducted by the blood to the skin surface at a higher rate of transport. Here it is radiated away into the environment.
If this radiation proves inadequate because the temperature of the environment does not permit the radiant heat to be absorbed rapidly enough, a second mechanism is triggered. The rising temperature of the blood flowing through the anterior hypothalamus triggers the sweating mechanism. This mechanism is extremely sensitive and capable of responding to a change in temperature of the blood of one hundredth of a degree Centigrade. Through some two million sweat glands of very complex design, a remarkably pure watery fluid is expressed with considerable force onto the skin surface. There it evaporates and, in doing so, cools the skin with extraordinary effectiveness.
It is not uncommon for a man exercising on a treadmill in a hot chamber to lose as much as five pounds of body water by this means within one hour. Meanwhile his body temperature will experience surprisingly little rise. If, by the use of drugs (atropine, for example), the sweating mechanism is blocked, body temperature will rise precipitously; fatal heat stroke becomes a real probability within a comparatively few minutes unless steps are taken to reduce the body temperature by some other means and as quickly as possible.
But to be effective, cooling by this means demands that the environment be able to absorb the water thus evaporated. If the water content of the atmosphere is already near the saturation point (we commonly say, "The relative humidity is high"), then our sweating mechanism becomes almost useless. It does serve a secondary purpose, the fluid itself acting in part as a fungicide on the skin. But apart from this, the sweat water merely runs down and collects in our shoes! Thus, in any environment which combines high temperature and high humidity, maintaining a normal body temperature is a serious problem.
In two areas of the world, just such a situation seems to have existed for a very long time, yet man has spread into these places and established himself successfully. So have a number of warm-blooded animals whose body temperature is equally critical to their survival. The environmental pressure in these areas, acting day and night upon man and the animals, has caused a modification of body form which is greatly to the advantage of the individual in this respect. In the Congo region, body mass has been substantially reduced, giving rise to communities of Pygmy people. In Abyssinia, body shape has been surprisingly elongated into a wirelike form, giving rise to the Negro giants. Both responses serve the same end, making for increased fitness in areas of a combined high heat and high humidity. The reasons why these two forms are an advantage are well-enough understood in terms of the physics of heat transport.
To accelerate cooling, it is desirable to shorten the distance that the heat must be conducted to escape to the environment. Consequently the smaller the body, the better the rate of heat removal, since it has less distance to travel from the center to the surface. Fortunately a further advantage of a smaller body is the fact that the surface area increases relatively as the mass is reduced, and this again makes it an ever better heat radiator. It is an advantage in every way to be small, if we have in view the maintenance of body temperature in the heat.
Suppose we have a cube measuring twelve inches on each side, having therefore a volume of one cubic foot. And let us say that one cubic foot weighs one pound. This one-pound body has a total surface area of six square feet. If we enlarge the cube so that it now measures twenty-four inches on each side, we shall now have a body of eight cubic feet, which (assuming it is made of the same stuff) would have a comparative weight of eight pounds instead of one. But the surface area has now become enlarged to twenty-four square feet. This looks like a great improvement. However, relatively it is quite the opposite. The surface area relative to body weight in the smaller cube is 6 to 1; in the larger cube the surface area relative to body weight is 24 to 8, or only 3 to 1. Therefore, the smaller body with its smaller heat capacity has a much larger surface area from which to radiate any excess heat: it is better off in every way.
There is an alternative method of improving the relative radiating surface area. This is to elongate the body into a long, thin, wirelike form. The effect is basically the same, namely, to increase the surface area relative to the mass and to decrease the distance from the center to the surface. This is precisely what has happened to the Nilotic Negro.
It is a striking fact that the Pygmy and the giant occupying a similar environment in Africa are paralleled by Pygmies and giants occupying a similar environment in South America. The Pygmy tribe known as the Yushes, who average about thirty-nine inches in height, live along the banks of the Curanja River in the border area common to Brazil, Peru, and Bolivia. They are neighbor to a community of people called the Hurayos, who are found to be more than six feet tall. (31) Pfeiffer notes that Louis Leakey, excavating in Nairobi in 1961 and in Zaire, found the remains of a pygmy giraffe and a pygmy elephant. (32) Perhaps these also responded to a hot, humid environment in a similar way.
That both the Nilotic Negroes and the Ituri Pygmies are examples of dauermodifications in man is suggested by the fact that transplantation to a different environment leads to a gradual shift to the normal proportions of the majority of human beings in the new environment surprisingly quickly. The speed with which such modifications can occur was remarkably demonstrated by the findings of Franz Boas when he was asked by a U.S. Senate Committee in 1911 to undertake a survey of the effect on the population as a whole of the admission into the New World of a large number of immigrants of different physical type. The question at issue was whether these immigrants were really being absorbed into the population or forming communities which preserved their physical identity. Was America truly a "melting pot," or merely a "gathering place"? Boas set out to measure, among other things, successive changes in head form, first of immigrant parents and then of their children born in America. If the trend was toward the American mean, all was well. If the children in successive generations preserved their parental head form, then it was clear that physically at least they were not "melting."
What Boas found was so unexpected that, even after nearly twenty years, the interpretation of his data was still being violently disputed. He discovered that the conformity of the head form of children born to immigrant parents converged more nearly toward the American mean in proportion to the time spent by the parents in America before each child was actually born. A child born one year after the parents arrived showed a measurable convergence toward the American mean. A child born three years after their arrival showed a greater measure of convergence. A child born to the same parents ten years after the parents landed showed even greater conformity to the American mean---and greater divergence from the parents' head form. Thus the New World environment evidently began to influence the head form of the children prenatally and with greater and greater force the longer the period of time spent by the mother and father in their adopted country before the conception of the child. In some way the environment was influencing the germ plasm.
Boas measured nearly eighteen thousand subjects. His data were unequivocal. And he was as surprised as his critics by what he found. The results of this survey demonstrated undeniably that there was a positive and direct influence of the new environment at work on the parental germ plasm (or more precisely, perhaps, on the parental germ plasm plasmagenes), modifying the cranial form of the children more and more positively as the children were born later and later to the immigrant family. The parents themselves did not undergo this modification.
These discoveries created so much argument and criticism over the ensuing years that in 1928 Boas decided to publish the whole mass of data under the title Materials for the Study of Inheritance of Man, in the hope that his conclusions would be vindicated. But as Melvin J. Herskovits later observed in his biography of Boas: "A detailed analysis of the reactions to this study, if it is ever made, will comprise an enlightening chapter in the intellectual history of our times." (33)
Not one critic took the trouble to examine the evidence, which is now known to be unimpeachable. Herskovits comments: "One still encounters statements to the effect that Franz Boas made an extended study of the effect of immigration to the United States on the head form of immigrants, concluding that the American environment was providing a new physical type. This conclusion has since been shown to be false." (34)
In a manner of speaking, such a conclusion was indeed false---but Boas did not make any such claim for his data. He demonstrated precisely the opposite. What he succeeded in doing was providing evidence for a gradual change in head form in response to some as yet unidentified environmental pressure which was becoming increasingly embedded in the germ plasm and being passed on to the grandchildren. An acquired character was becoming inheritable. Dauermodification was being demonstrated in man. There is no reason to doubt that had the children returned to their parents' homeland and in turn raised families, these later generations would have displayed the same increasing tendency to revert back to the parental head form which, in the first place, had been the result of a response to their native environment. Dauermodifications are inherited progressively only so long as the modifying environment maintains the pressure in the same direction.
The responsiveness is pervasive. It has been largely denied in recent years because, having formulated a theory of inheritance unfavorable to it, we have become incarcerated in the straitjacket of our prejudices. We soon become unaware of these prejudices, and because they are held unawares, they are largely immune to contrary evidence or to reexamination.
Yet many authorities have continued to preserve an open mind throughout this rather bleak period of evolutionary dogmatism. Writing on "The Inheritance of Acquired Characters" in the British journal Nature, E. W. MacBride observed in l932: (35)
Since changed habits, by exercising different parts of the body, do modify structure, and since we know that animals can and do change their habits in response to the demands of a changed environment, it is a natural inference that the changed habits are the cause of changed structure, and that the structural response of the individual has finally become engrained in the heredity of the race. So strong is the evidence for this inference, that some of my friends among the leading systematists of the British Museum deny altogether the necessity for direct evidential confirmation of it, arguing, with probable justice, that so many generations would be needed to make the change manifest that the time required would far exceed the span of an experimenter's life.
This is one of the problems. We often do not know whether laboratory experiments are or would be a test of what happens in nature. Such experiments are the best we can do, but they do not really reproduce natural conditions. Man's "interference" introduces unrecognized changes in the conditions of a test which, for all we know, may invalidate such tests. Observations of animal behavior in zoos or in any kind of captivity severely misguided earlier naturalists about the behavior of animals when they were free. Captivity introduced hostilities due to crowding and other unknown factors which were unforeseen but are now known to have distorted our understanding of natural behavior. Hence arose the mistaken doctrine that nature was "red in tooth and claw " a kind of interminable battlefield of savagery.
We have spoken of changes in head form among modern immigrants. The evidence shows that such progressive head-form modifications are an ancient phenomenon. It has been reported by W. S. Laughlin for the earliest settlers in the New World who entered by crossing the Bering Straits. (36) From the fossil remains of the palaeo-Aleuts to those of the neo-Aleuts a very pronounced change in head form has been demonstrated. It is quite clear from the evidence that the transition was continuous and did not represent the intrusion of new immigrant populations. Moreover, there is a clear indication of other bodily changes, including lengthening of the trunk and shortening of the limbs through successive generations.
This change, which is observed for Arctic animals also, is a response to cold, a means for the conservation of heat by producing a more massive heat reservoir (the trunk) and reducing the size of the chief areas of heat radiation loss, the limbs and the extremities (hands and feet in man, or paws in animals). Children of modern Eskimos are born with these modifications. When the adult Eskimo stands up he is shorter than the white man, but when he sits down he appears to be much the same height. The shortening is thus in the limbs, while the trunk has remained unchanged except for some thickening. According to Laughlin, the modification occurred in the earliest settlers with remarkable rapidity.
An editorial comment in Scientific American under the title, "Stature and Geography," makes reference to the modifying influences of cold: (37)
The farther from the equator you were born and raised, the bigger you are likely to be. This fact has been confirmed in some new studies by Marshall T. Newman, anthropologist with the Smithsonian Institution. Carl Bergman, a nineteenth-century German biologist, predicted that members of a species of warm-blooded animals living in cold climates should be larger than those in warmer. A bigger individual has less skin area in proportion to total volume and so less tendency to dissipate heat.
It will be recognized that this is precisely the converse of animal response to high heat and humidity. The article reports that Newman tested this out for pumas also and found it to apply equally. He might have noted that the same is true for the bear family: polar bears have larger body mass but shorter limbs, in proportion, than their more southern relatives.
The author, guided by conventional Mendelian principles of inheritance, then reasons that the genes cannot have been influenced in any way and that the modification cannot therefore have become hereditary. I do not think that the evidence from bears in zoos is sufficient to allow such a conclusion. It would he important to compare the fetuses of these bears and pumas in the Arctic with those of the more southerly species. We should then be in a better position to say whether the environmental pressure had produced an inheritable effect.
There is evidence that fetal studies with such an end in view could be very worthwhile. Sir Peter Medawar has pointed out, for example, that both human beings and guinea pigs are born with a thicker epidermis on the sole of the foot than elsewhere on the body. (38) One might account for this by saying that it is an example of pre-adaptation (a rather mystical concept, but one which is supported by a number of remarkable apparent examples), or a pure coincidence (which is possible, of course), or the direct activity of God in nature. Or it may be a good example of a dauermodification. At the moment there is no way of knowing what is the correct explanation. But Medawar seems to be in favor of the view that this is a case of an acquired character which has become inheritable.
C. H. Waddington refers to certain callosities on the ostrich breast upon which it rests its weight when squatting, and he notes that these callosities are found in the unhatched chick. Since the inheritance of acquired characters is still a concept to be shunned, he refers to this as a case of "genetic assimilation." (39) But, as Shakespeare put it, a rose by any other name will smell as sweet, and we have here, surely, another example of cytoplasmic inheritance concealed under a different name.
In another article titled, perhaps more significantly, "Experiments in Acquired Characters," Waddington deals with the same topic and uses the same basic examples by way of illustration. (40) However, he refers in addition to the African wart hog, which has the habit of kneeling on its wrists when feeding. The skin in both these places of contact is thickened in the newborn. Waddington prefers to term this a case of "anticipatory adaptation." Apparently prejudice against dauermodifications was still too strong to allow him to admit this as a possible example of such, in spite of the title of his paper.
The peculiar fitness which characterizes living things applies equally to the primates which are supposed to be related to or fall within the lines of man's evolutionary path. This subject interests me, because I think it may throw light on something which many Christian people find it difficult to account for. Those who believe that Adam was a separate creation find themselves called upon to explain the fact that there appears to have been a succession of creatures which increasingly approached man's present form and did so more and more closely as they appeared later and later in time. If one is not too concerned with their supposed chronological ordering, it is possible so to arrange these specimens serially in such a way that the idea of human evolution via some such succession of form is well-nigh logically compelling. Time-Life publications are particularly good (or bad) at presenting this kind of compulsive argument by an adept use of reconstructed forms walking across extensive fold-out pages. (41)
But there is perhaps another explanation. It could conceivably be that as the environment on the earth's surface more and more nearly approached an appropriate condition for the introduction of man, so did living forms like man appear with greater frequency. Such creatures were responding to the environmental pressures and showed by the forms they increasingly assumed that the environment, for such a creature as man was to be, was more and more nearly ready for human occupancy.
We know from Isaiah 45:18 that God intended the earth to be a habitation for man. This was His plan. He could have completed its preparation in a moment of time, by fiat creation. But why should God try to save time? Before the appearance of man, time was of no consequence whatever. Moreover, instantaneous creation would not have allowed us to enter with understanding into the planning stages by which God brought it all about and thus to share something of His own---could we say---"excitement" in prospect.
There is, after all, some precedent for this idea. We are told in Genesis 1:26 not only that God held a sort of divine conference before creating man, but also that He used the dust of the ground to form his body and then as a second step breathed into the body and gave it life. This is a form of creation by stages. It signifies a kind of deliberateness. What better reason could there be for telling us this by revelation than to let us share something of God's special interest in what He was doing, an interest which evidently did not attach in the same way to the creation of other forms of life. In these other cases we have only cryptic statements such as "Let the earth bring forth" (Gen. 1:11) or "Let the waters bring forth" (Gen. 1:20), suggesting simply the fiat creation of God, who needed only to speak and it was done.
In short, I am suggesting that we have been allowed to discern something of the stages of preparation of the earth for man and that what we thus see bears witness to the fact that the process was a very deliberate and carefully planned one. When it was nearly ready for man, it was of necessity also nearly ready for creatures very like him in their physical constitution, though the differences between these creatures and man himself were still so great as to place them and him in two entirely different kingdoms. (42)
Now, Wood Jones made an observation about primates in this context which I want to quote even though he certainly did not have any such elaborate concept as I have presented above. This is what Jones wrote: (43)
Although it is a subject not generally palatable to those Darwinian enthusiasts, who see an easy progress toward human "perfection" along the line of the supposed uniserially Primate series, it is worthwhile to note that parallel developments are seen to perfection in the Order Primates as it is at the present recognized.
Animals that are universally recognized as monkeys have been produced twice over from independent stocks. The New World Monkeys (Platyrrhini) and the Old World Monkeys (Cattarhini) are of admittedly different origin and have come to resemble each other---and become, popularly, monkeys by a parallel development.
Even a third monkey type was developed during the hey-day of the Lemuridae in Madagascar (Neopithicus), upon its discovery as a fossil in Madagascar (1896), it was hailed as a new and intermediate type of monkey: and were it to be living today, it would probably still be regarded popularly as a monkey. But any assumption of parallelism or convergence among the members of the Order to which man is assigned is so frowned upon by orthodoxy that, for the moment, we will leave the question without further discussion.
We need only to assume that God prepared the earth for man in an orderly way so that, just before man's appearance, the total environment was ideal for him even as he was for it. Man was ideal for the environment in the sense that while he remained unfallen, he was constitutionally a perfectly equipped governor and director and manager of all plant and animal life. We need then only assume that all living things (perhaps even including himself) were provided with an appropriate mechanism of adjustment which would permit what we now call dauermodifications in order that man might make use of and direct the development of these living things wisely and well to maximize their potential and thus enhance the work of God as His appointed representative.
Such a mechanism, operating even before man was introduced, would account for the manlike forms which preceded him, resulting from a power of adjustment found in certain species to fit them to an environment tending more and more to the ideal for man himself.
We have elsewhere set forth a hypothetical reconstruction of the events immediately preceding the creation of Adam and Eve, (44) events which I believe were catastrophic and came as a judgment and are intimated by the descriptive terminology which is employed in the original Hebrew of Genesis 1:1. (45) So I shall not elaborate further on this point here. But I think it could be argued with some cogency that when man was first created, the Garden paradise into which he was introduced was the one habitat, of all possible habitats, that was most completely suited both for himself and for all the living things which shared it with him. But it was not merely a habitat that arose by chance and was therefore chosen simply because it was most suitable. It was deliberately planted (Gen. 2:8)---that is, it was engineered by the divine Gardener and filled with just such forms of life as would constitute a paradise of harmony in which nothing was lacking and nothing in excess, no competition and no waste.
Had Adam not fallen, he would perhaps have been called upon to extend the boundaries of this Garden until it finally covered the earth. This could have been the work appointed for him by which he would have matured and been made perfect.
This expansion of paradise would have been an achievement made possible, not so much by interference with the natural order as it existed outside its boundaries, but by making optimum use of the built-in potential of all living things for both stability and cumulative adaptation. God had provided two pathways of inheritance---the nuclear to preserve order, and the cytoplasmic to allow variety and ensure fitness.
A half-truth---the recognition of the laws governing nuclear inheritance, hitherto taken as the whole truth---seems to have led us into the fundamental error of making chance the creator of order. Perhaps we are now in a better position to correct this incomplete picture and recognize once again the providence and wisdom of God in creation.
References:
1. Charles Darwin: Life and Letters, ed. Francis Darwin, Murray, London, 1888, vol. II, p. 369, in a letter to T. Davidson dated 30 April.
2. Ibid., p. 390.
3. Darwin, Charles, The Origin of Species by means of Natural Selection, Murray, London, 6th ed., 1872, chap. 15, p. 42l.
4. Charles Darwin: Life and Letters, ed. Francis Darwin, Murray, London, 1888, vol. III, p. 159.
5. Ibid., vol. II, p. 232.
6. Huxley, Sir Julian, "Inheritance of Acquired Characteristics" in Essays in Popular Science, Penguin, Harmondsworth, England. 1938, pp. 36-37.
7. The very persistence of many forms over supposedly millions of years without significant change is evidence of this. The stability of many organisms over enormous periods of time is astonishing.
8. Jones, F. Wood, Trends of Life, Arnold, London, 953, especially chap. 12, p. 128, "The Inheritance of Adaptations."
9. Jollos, V., "Experimentelle Untersuchungen an Infusorien," Biol. Zblt. 33 (1913):222-36.
10. Lindsey, Arthur Ward, Principles of Organic Evolution, Mushy, St. Louis, 1952, p. 342.
11. Ephrussi, Boris, Nucleo-cyloplasmic Relations in Micro-Organisms, Oxford Univ. Press, 1953, p. 4.
12. Ibid., p. 6.
13. Ibid., p. 100.
14. Prosser, C. I., "The Origin After a Century: Prospects for the Future" in Amer. Scientist 47 (1959):545.
15. Grant, Verne, The Architecture of the Germplasm, Wiley, New York, 1964, p. 15.
16. Ibid., p. 19.
17. Micehaelis, P., "Cytoplasmic Inheritance in Epilogium and its Theoretical Significance" in Advances in Genetics 6 (1954):287-401.
18. Kuhn, Alfred, Lectures on Developmental Physiology trans. by Roger Milkman, Springer-Verlag. New York, 2nd ed.. 1971, p. 83.
19. Ibid., p. 489.
20. HuxIey, Sir Julian, ref. 6, pp. 36-37.
21. See Lucien Cuenot, L'evolution biologique: les faits, les uncertitude. Masson, Paris, 1951; F. Wood Jones, Trends of Life, Arnold, London, 1953; Sir Alister Hardy, The Living Stream, Collins, London, 1965; W. R. Thompson, introduction to Centennial edition of Darwin's Origin of Species, Dent, New York, 1959.
22. Sir Cycil Hinshelwood: quoted by Donald Michie, "The Third Stage in Genetics" in A Century of Darwin, ed. S. A. Barnett, Heineman, London, 1958, p. 65.
23. Frogo: Maynard Smith, The Theory of Evolution, Penguin, Harmondsworth, England, 1958, p. 189; and salamanders, Edward Dodoun, A Textbook of Evolution, Saunders, Philadelphia, 1952, pp. 318,321.
24. Dodson, Edward, ref. 23, p. 321.
25. Moore, John A., "An Embryologist's View of the Species Concept" in The Species Problem, ed. Ernst Mayr, A.A.A.S., Washington, D.C., 1957, p. 329.
26. Dodson, Edward, ref. 23, p. 318.
27. See New Scientist, 26 February 1976, p. 439 under the heading "Green Toads Sing their Way through Evolution." The frequency and pitch of the toad's mating call is modified by the range of temperature within which the young are matured, and only toads with the appropriate calls any longer attract one another. The community is therefore broken up somewhat by the effects of different temperatures on the young.
28. Sonneborn, T. M., "Breeding Systems, Reproductive Methods, and Species Problem in Protozoa" in The Species Problem, ed. Ernst Mayr, A.A.A.S., Washington, D.C., 1957, p. 233.
29. 0n this, see "Convergence and the Origin of Man," Part III in Evolution or Creation?, Volume IV of the Doorway Papers.
30. Jones, F. Wood, ref. 21, p. 84.
31. Reported in the Toronto Telegram, 20 October 1970, from a published statement by the Roman Catholic Church, vicariate in Puerto Maldonado, Peru, 1970. See also, Thomas Gladwin, "Climate and Anthropology" in Amer. Anthrop. n.s. 49 (Oct.-Dec. 1947):609ff
32. Pfeiffer, John E., The Emergence of Man, Harper and Row, New York, 1969, pp. 40, 94.
33. Herskovits, Melville J., Franz Boos, Scribners, New York, 1953, p. 40.
34. Ibid., p. 41.
35. MacBride, E. W., in Nature 129 (1932):900.
36. Laughlin, W. S., "The Eskimos and Aleuts: Their Origins and Evolution" in Science 142 (1963):633-43.
37. "Stature and Geography," in Sci. Amer., April 1954, p. 46.
38. Medawar, Sir Peter, The Uniqueness of the Individual, Basic Books, New York, 1957, p. 84.
39. Waddington, C. H., "Evolution of Adaptations" in Endeavour, July 1953, pp. 134-39.
40. Waddington, C. H., "Experiments in Acquired Characteristics" in Sci. Amer., December 1953, p. 92f.
41. See, for example, Early Man, ed. F. Clark Howell, Life Nature Library, Time-Life Books, New York, 1965, pp. 41-45.
42. For a detailed analysis of these differences, see "Is Man An Animal?" which is Part V in Evolution or Creation?, Volume IV of the Doorway Papers.
43. Jones F. Wood, Trends of Life, Arnold, London, 1953, p. 85.
44. See on this, "A Christian World View, The Framework of History." Part V in Noah's Three Sons, Volume I; and "The Preparation of the Earth for Man," Part I in Evolution or Creation?, Volume IV of the Doorway Papers.
45. 0n this see "Between the Lines: An Analysis of Genesis 1:1, 2," Part VI in Time and Eternity. Volume VI of this series.
Corrections, June 25, 1997.