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Part I

Part II

Part III

Part IV



     

Part IV:  The Fitness of Living Things: Dauermodifications

Chapter 4

Dauermodifications in Man

     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 colour, and supernumerary fingers and toes are probably the consequence of gene mutations. That skin colour 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 (98.6 degrees F.) of only a few degrees can rather quickly prove fatal.

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    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

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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 centre to the surface. Fortunately a further advantage of a smaller body is the fact that the

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surface area increases relatively as the mass is reduced, and this again makes it an evern 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 centre 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 neighbour 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

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 American Anthropologist, new series. vol.49, Oct.-Dec., 1947, p.609ff
32. Pfeiffer, John E., The Emergence of Man, Harper and Row, New York, 1969, pp. 40, 94.

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modifications can occur was remarkably demonstrated by the findings of Franz Boas when he was asked by a United States 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

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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 unfavourable 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 re-examination.
     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
 
33. Herskovits, Melville J., Franz Boos, Scribners, New York, 1953, p.40.
34. Ibid., p.41.
35. MacBride, E. W., in Nature, vol.129, 1932, p.900. 

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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 behaviour in zoos or in any kind of captivity severely misguided earlier naturalists about the behaviour 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 behaviour. 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

36. Laughlin, W. S., "The Eskimos and Aleuts: Their Origins and Evolution" in Science 142 (1963):633-43. 

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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 be 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

37. "Stature and Geography," in Scientific Amererican, April, 1954, p.46.
38. Medawar, Sir Peter, The Uniqueness of the Individual, Basic Books, New York, 1957, p.84.
 

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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

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.
 

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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" (Genesis 1:11) or "Let the waters bring forth" (Genesis 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)

42. For a detailed analysis of these differences, see "Is Man An Animal?", Part V in Evolution or Creation?, vol.4 in The Doorway Papers Series.
43. Jones F. Wood, Trends of Life, Arnold, London, 1953, p.85.
 

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     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 man-like 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

44. See on this, "A Christian World View, The Framework of History", Part V in Noah's Three Sons, vol. 1; and "The Preparation of the Earth for Man," Part I in Evolution or Creation?, vol. 4; in The Doorway Papers Series, Zondervan Publishing Company.
45. 0n this see "Between the Lines: An Analysis of Genesis 1:1, 2," Part VI in Time and Eternity. vol.6 in The Doorway Papers Series.
 

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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 (Genesis 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. 

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Copyright © 1988 Evelyn White. All rights reserved

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