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About
the Book
Table of Contents
Part I
Part II
Part III
Part IV
Part V
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Part III: Convergence and the Origin
of Man
Chapter 2
The Fact of Convergence
IT MUST be apparent that if convergence
is at all common, many forms which have been used to establish
genealogical trees of evolutionary significance may not in fact
form trees at all but merely, as Manton (9) put it,
"bundles of twigs," quite unrelated in any but the
most non-evolutionary sense. The genealogical trees are then
entirely fictitious, nothing less than misrepresentations of
the course of biological history. One's confidence in these phylogenetic
reconstructions cannot be very high.
Darwin
himself was uncomfortably aware of this fact. In the sixth edition
of The Origin of Species he wrote: (10)
It should
not be overlooked that certain strongly marked variations which
no one would rank as mere individual differences, frequently
occur owing to a similar organization being similarly acted on,
of which numerous instances could be given with our domestic
production.
In 1876, in a letter to Moritz Wagner,
he wrote: (11)
In my
opinion the greatest error which I have committed has been in
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.
A curious course of events followed
publication of Darwin's work. One result was an increasing neglect
of the study of the relationships between form and function,
due to an almost total obsession with the tracing of supposed
lines of descent on the basis of form. Morphology totally absorbed
the attention of most students of fossil remains. The second
was a counter-balancing search by those
9. Manton, I., Problems
of Cytology and Evolution in the Pteridophyta, Cambridge
University Press, 1950: quoted by I. Knoblock, Journal of
the American Scientific Affiliation, vol.5, no.3, 1953, p.14.
10. Darwin, Charles, The Origin of Species, 6th edition,
1872, p.74.
11. Darwin, Charles, Life and Lectures, October 13, 1876,
iii, p.159.
 pg
1 of 14 
who opposed
Darwinism (not necessarily "evolution" per se),
for instances of structural parallelism between living forms
which had developed in entire independence and were not believed
to be linear descendants.
With
respect to the first, Sir James Gray, the author of a classical
work on animal locomotion, wrote on the theory of natural selection:
(12)
Strange
as it may seem, one immediate effect of The Origin was
a marked recession in the study of animal function. There was,
and still is, a tendency for morphologists to ascribe to organs
and structures a functional significance for which there was,
or is, little observational evidence. In this respect "Evolution
in action" (Julian Huxley) is by no means guiltless �
it goes a considerable way beyond the physiological facts. Is
Dr. Huxley quite sure that the loss of the lateral digits by
the ancestors of the horse gave them an "additional turn
of speed"?
This same obsession with form irrespective
of function led Haeckel to formulate his well-known but now quite
discredited theory of recapitulation. Sir Gavin de Beer observed:
(13)
The assumption
that developmental stages of a descendant represent adult ancestral
types has taken all the longer to disprove because of the facile
way in which non-crucial observations have been claimed as evidence
in its support. . . . In many cases it can be proved that the
developmental history cannot represent the phylogenetic history,
for the reason that if the adult ancestor resembled the modern
embryo, it could not have been functional. . . .
The second
and, perhaps, the more important reason for which the theory
of recapitulation has impeded the progress of biology is that
it has blinded embryologists to the necessity of looking for
causal connections (i.e., functional ones) within ontogenetic
phenomena.
In other words real or superficial
resemblances were, and are still, assumed to be evidence of linear
descent or close genealogical relationship, whereas they may
be functionally determined parallelisms resulting from the similar
response of living organisms to similar stimuli. So de Beer concluded
with a quotation by the great embryologist Wilhelm His: (14)
This opposition
to the application of the fundamental principles of science to
embryological questions would scarcely be intelligible had it
not a dogmatic background. No other explanation of living forms
is allowed than heredity, and any which is founded on another
must be rejected. The present
12. Gray, Sir James, in a
review of Huxley's Evolution in Action, under the heading
"The Case for Natural Selection," in Nature, February
6, 1954, p.227; and August 7, 1954, p.279.
13. De Beer, Sir Gavin, "Embryology and Evolution,"
in Evolution, edited by de Beer, Oxford University Press,
1938, pp.58, 61.
14. Ibid., p.62.
pg.2
of 14
fashion requires
that even the smallest and most indifferent inquiry must be dressed
in a phylogenetic costume.
This was written by Dr. His in 1888.
Some years later, in respect to the conclusions of physical anthropologists,
Wilson Wallis wrote sadly: (15)
Since
the day of Darwin, the evolutionary idea has largely dominated
the ambitions and determined the findings of physical anthropologists,
sometimes to the detriment of the truth.
And there is no doubt whatever that
the famous Piltdown fraud could never have succeeded as well
as it did but for the fact that Dawson supplied for the experts
precisely what some of them believed they ought to have. Piltdown
Man was just what the doctors ordered. V. F. Calverton, in his
introduction to The Making of Man wrote: (16)
The very
simultaneity with which Darwin and Wallace struck upon the theory
of Natural Selection and the survival of the fittest was manifest
proof of the intense activity of the idea at the time. Every
force in the environment, economic and social, conspired to the
success of the doctrine.
Similarly, A. L. Kroeber wrote:(17)
There
was evidently a particular historic concatenation in the world's
thought which enabled Darwin's discovery to trigger off consequences
so great.
In protest against this landslide
of approval of a theory which was surprisingly suited to the
Zeitgeist (as many and recent historians have pointed
out), a number of independent minds set out to take a fresh look
at the evidence. Prince Kropotkin re-examined the community of
wild life to see whether there really was a "struggle to
survive" and whether the fittest only came out on top. He
found a very different pattern in Nature and set forth his findings
in his Mutual Aid. Until comparatively recently it was
long out of print. But the tide seems to be changing, and there
is now a fresh demand which has justified its reprinting. Similarly,
in 1922 Leo Berg wrote his massive and scholarly Nomogenesis
as a protest against the then unbalanced concern with morphology
to the exclusion of function. He would probably today have called
his book Convergence, for that is
15. Wallis, Wilson D., "The
Structure of Prehistoric Man," in The Making of Man,
Modern Library, Random House, New York, 1931, p.75.
16. Calverton, V. F., in The Making of Man, Modern Library,
Random House, New York, 1931, p.2.
17. Kroeber, A. L., "Evolutionary History and Culture,"
in Evolution After Darwin, vol.2. Univeristy of Chicago
Press, 1960, p.1.
pg.3
of 14
what
it is all about. It, too, has now been republished � surprisingly,
by the Massachusetts Institute of Technology. Shortly after this
first edition appeared, in 1935 Sir Wilfrid LeGros Clark was
willing to admit: (18)
In the
evaluation of the genetic affinities, anatomical differences
are more important as negative evidence than anatomical resemblances
are as positive evidence. It becomes apparent that
if this thesis is carried to a logical conclusion it will be
necessary to demand a much greater scope for the phenomena of
parallelism or convergence in evolution than has generally been
conceded by evolutionists. The fact is that the minute and detailed
researches which have been carried out by comparative anatomists
in recent years have made it certain that parallelism in development
has been proceeding on a large scale and is no longer to be regarded
as an incidental curiosity which has occurred sporadically in
the course of evolution. Indeed, it is hardly possible for those
who are not comparative anatomists to realize the fundamental
part which this phenomenon has played in the evolutionary [developmental?]
process [query mine].
Yet today one hears very little on
the subject, as the encyclopedias indicate. Sir Wilfrid himself,
in contributing to the rash of Darwinia which were published
in the Darwin Centennial year ( l958) wrote: (19)
Reference
should be made to the evolutionary phenomena of convergence and
parallelilism, for it is well known that these can lead to structural
similarities which, taken by themselves, may be misleading. The
term convergence is applied to the occasional tendency for distantly
related types to simulate one another in general proportions
or in the development of analogous adaptations in response to
similar functional needs.
What had happened in the 25 or so
years to convert Clark's "large scale" phenomena "no
longer to be regarded as an incidental curiosity" into an
"occasional tendency"? Perhaps it had become increasingly
apparent during the intervening years that the admission of the
fact of convergence on a large scale was highly inimical to many
of the more commonly displayed genealogical trees purporting
to show linear evolutionary descent based purely on morphololgy.
So
crucial is morphology that the anthropologist Franz Weidenreich
formulated the following principle:
(20)
In determining
the character of a given fossil form and its special place in
the line of human evolution, only its morphological features
should be made the basis of decision: neither the location of
the site where it was recovered,
18. Clark, Sir Wilfrid LeGros,
Early Forerunners of Man: quoted by Rendle Short in Transactions
of the Victoria Institute, vol.66, 1935, p.255.
19. Clark, Sir Wilfrid LeGros,"The Study of Man's Descent,"
in A Century of Darwin, edited by S. A. Barnett, Heineman,
London. 1958, p.182
20. Weidenreich, Franz, "The Skull of Sinanthropus pekinensis:
A Comparative Study on a Primitive Hominid Skull" Paleontologica
Sinica, N.S.D., no.10, whole series no.127, 1943, p.1.
pg.4
of 14
nor the geological
nature of the rock stratum in which it was imbedded is important.
But what does one make of this demand
that the evidence of geology be ignored and only physical appearance
considered? In the light of the possibility that structure may
be entirely the result of environmental or historic circumstances
and have nothing whatever to do with geological age, the argument
is entirely without validity.
Sir
Solly Zuckerman, though fully committed to evolutionary theory,
admitted freely: (21)
Several
gene patterns may have identical phenotypic effects (so that)
when we deal with limited or relatively limited fossil material,
correspondence in single morphological features or in groups
of characters does not necessarily imply genetic identity and
phyletic relationship.
By the phrase "several gene patterns,"
Zuckerman is referring to the well-recognized fact that where
circumstances "demand" that an animal be equipped with
some particular organ (a special kind of eye for example); that
organ is apt to appear even though the animal does not share
a gene complex which has been responsible for the very same organ
in some other species. Thus gene complexes or patterns which
differ, can nevertheless lead to the production of similar structures
in unrelated animals.
Wood
Jones argued strongly that there was some kind of "vital
force" in nature which resulted in the emergence of all
sorts of specialized structures in animals that enabled their
possessors to meet the particular exigencies of their lives.
Such structures, he was convinced, could appear "out of
the blue," as it were, almost upon demand. He listed many
examples in his classic little volume Trends of Life,
all of which were chosen to demonstrate that in some mysterious
way "Nature knew what it was about." Like Leo Berg,
and now even more recently Sir Alister Hardy, (22) Jones,
too, was persuaded that there was little or no element of chance
or randomness about this phenomenon. He wrote: (23)
Since
the acceptance of Charles Darwin's theory of Evolution, many
attempts have been made by distinguished biologists (such as
Gaskill and Patten) to prove that the invertebrates did in fact
"evolve" into vertebrates; but all the available evidence
makes it quite certain that the two great phyla arose in complete
independence of each other. . . .
When ordinary
people were told by the dogmatic propagandists of
21. Zuckerman, Sir Solly,
"An Ape or The Ape?" Journal of the Royal Anthropological
Institute, vol.81, 1951, p.57.
22. Hardy, Sir Alister, The Living Stream, Collins, London,
1965, especially chap.7, pp.180ff., "Habit in Relation to
Structure."
23. Jones, F. Wood, Trends of Life, Arnold, London, 1953,
pp.74, 75.
pg.5
of 14
Darwin's theory
of Evolution that so complex a thing as an eye had come into
existence by some vague force known as Natural Selection, acting
on chance minor structural variations, their credulity was taxed
to the utmost. Their faith would probably have failed them completely
had they been asked to believe that this random and mechanistic
process had produced the vertebrate eye and the invertebrate
eye in complete independence; and more than that, had permitted
the invertebrates to originate at least three different kinds
of eyes in independence, within the limits of their own phylum
(the singlefocal eye, bifocal eye, and compound eye). Not only
eyes, but ears, and hearts and gills, and lungs, and livers,
and kidneys, and brains, and all the rest have been developed
twice over in complete independence in the two great phyla.
And as we shall show, Jones' list
barely scratches the surface of the less obvious parallelisms
that exist. Some hitherto unrecognized or ill-defined law has
been at work governing all life. Naturally, in the present climate
of opinion, such concepts are too tainted with metaphysics to
be encouraged by the Establishment. They are rejected out of
hand. Everything must be left to chance. Evolution and Chance
are virtually synonymous concepts, and perhaps LeGros Clark (like
others) had begun to realize that convergence favoured development
by law, rather than by chance, too pointedly. It is quite clear
that this conviction certainly prompted Leo Berg to write his
classical study on convergence and to give it the more precise
title: Nomogenesis: Evolution Determined by Law. The idea
that there might be some law governing the development of living
forms throughout the ages is no more frightening, of course,
than the concept of the rule of law in physics. But the physical
events of the past have not shown any progress from simple to
complex, lower to higher, more dependent upon the environment
to less dependent on the environment, without conscious purpose
to a very high degree of purposefulness, and so forth, in the
way that living things have. In this sense there is a direction
to the development of life which is not evident in the mere physical
order. And the idea of "direction" according to "law,"
and to a significant extent contrary to the otherwise universal
rule of "decay" (entropy), inevitably raises the spectre
of purpose. And purpose implies a Purposer. This is where the
rub comes. . . .
So
pervasive did Berg see convergence to be, that he could write
without hesitation: "Convergence and not divergence is the
rule, not the exception. This appears to be all pervasive, both
among plants and animals, both present, recent, and extinct."
(24) And in the latest re-issue of his work we find him
saying: (25)
From the
examples set forth in this section, it is obvious that convergence
24. Berg, Leo, Nomogenesis:
Or Evolution Determined by Law, p.174 of the English edition,
Constable, London, 1926.
25. Berg, Leo, Nomogenesis: Or Evolution Determined by Law,
p.169 of the Massachesetts Institute of Technology edition, 1969.
pg.6
of 14
affects the most
important organs fundamental for existence, and not merely external
characters.
And again, later: (26)
From the
numerous examples that have been offered in this Chapter, and
their number might easily be multiplied, we have shown that convergence
affects the most fundamental organs in animals and plants, that
the phenomenon is widely distributed, and that points of similarity
which have been attributed to common descent are often due to
convergence.
Before examining the evidence in more
detail, it may be well to note, in fairness to other writers
since then, that although convergence is too dangerous a doctrine
to give much emphasis to, it is, nevertheless, quite widely admitted
by the Establishment. G. G. Simpson was willing to admit:(27)
In convergence,
there occurs the same sort of opportunistic development of one
way of life by different groups -- in this case those groups
being dissimilar (or less similar) in adaptive type to start
with. The trend towards greater similarity of adaptation involves
. . . converging functional and structural characteristics. The
groups may be nearly related or may be only very distantly related.
. . . . Insects and birds are so distantly related that any particular
homology between their parts can hardly be traced, and yet they
converge, sometimes quite closely.
Humming moths
(given by Evan Shute (28) as Hawk Moths, Trochilidae chordates) and humming
birds are so remarkably alike in habits and functional operation
that they are often mistaken for each other if seen only from
a distance. Convergence on a grand scale is seen in the comparison
of South and North American mammals.
Alfred S. Romer (29) observed
that "the development of long spindles to support a dorsal
tail occurred in at least two and perhaps five separate lines."
And he reported that Radfield had suggested to him these were
heat regulating mechanisms. This is most probable, I think. Such
a structure is to be observed in the Dimetrodon, for example.
Boule
and Vallois extended the principle somewhat: (30)
It would
be important to know whether we can not accept the existence
of convergence phenomena of biochemical characters, analogous
to the convergence phenomena of a morphological order. There
is no reason why a similar morphological evolution [development?]
in two different groups
26. Ibid., p.225.
27. Simpson, G. G., The Meaning of Evolution, Yale University
Press, 1952, pp.183, 184.
28. Shute, Evan, Flaws in the Theory of Evolution, published
privately, London, Ontario, 1961.
29. Romer, A. S., in Genetics, Paleontology and Evolution,
edited by Jepson, Mayr, and Simpson, Princeton Univerity
Press, 1949, pp.103ff.
30. Boule, Marcellin, and Henri V. Vallois, Fossil Man,
translated by M. Bullock, Dryden Press, New York, 1957, p.573,
footnote.
pg.7
of 14
should not he accompanied
by a parallel evolution of phenomena ascribable to biochemistry.
It seems that naturalists have not given attention to this point
[query mine].
As we shall see, biochemists per
se have given attention to the point, but dyed-in-the-wool
evolutionists have not given attention to the biochemists. In
speaking of man's ancestry, Ruggles R. Gates wrote: (31)
The abundance
of convergent types also involves recognition of the fact that
groups, such as mammals, which are now regarded as uniform [i.e.,
descended from a single ancestor] have had polyphyletic (i.e.,
independent) origin.
Alfred S. Romer (32) even went
so far a to say that "the known presence of parallelisms
in so many cases and its suspected presence in others suggests
that convergence may have been an almost universal phenomenon."
And Simpson seemed to be issuing the same caution against the
too hasty assumption of relatedness based on homologies when
he said: "Sanger has shown that the insulin composition
of sperm whales is identical with that of pigs and quite different
from that of sei whales! To be sure, a sequence of only three
amino acids is involved, and both differences and resemblances
could be accidental without even true convergence, but the lesson
is there." (33)
One
more example. Herbert Friedman, Curator of the Division of Birds,
U. S. Natural Museum, in a paper on ecological counterparts in
birds, presents a survey of the extraordinary parallels in unrelated
species of birds, including patterns of feeding, call, and nest-building,
as well as in colouration and structural details. He said: (34)
The more
complete our knowledge of any given group of organisms, the more
such cases come to mind. . . . The number of instances may be
extended to a point where it grows wearisome. . . .
The number of possible permutations
and combinations of the different colours and patterns (spots,
bars, stripes, etc.) found in birds is far greater than the number
of kinds of birds. It is therefore interesting, and probably
significant, that there should be as many instances of convergence
among unrelated groups as there are. It is all the more intriguing
when we find that these similarities in appearance are so often
correlated with equally marked similarities in habit.
31. Gates, Ruggles R., Human
Ancestry from a Genetical Point of View, Harvard University
Press, 1948, p 3.
32. Romer, A. S., in Genetics, Paleontology and Evolution,
edited by Jepson, Mayr, and Simpson, Princeton Univerity
Press, 1949, p.115.
33. Simpson, G. G., Biology and Man, Harcourt, Brace &
World, New York, 1969, p.38.
34. Friedman, Herbert, "Ecological Counterparts in Birds,"
Scientific Monthly, vol.63, no.5, 1946, p.395-398.
pg.8
of 14
So much, then, for acknowledgment
of the fact itself. It is to the work of Leo Berg in particular
that we must turn for the most complete examination of the evidence.
It indicates some measure of the renewed interest in the subject
as a whole that his original work, first published in Russian
in 1922, and in an English translation in 1926, is once again
available for study in 1970.
Consider a few examples of organs
and body fluids. According to Berg, the placenta,
by which the embryo is connected with the body of the mother
and by which it receives its nourishment and gets rid of its
waste products, has been independently formed in various groups
of animals including Polyzoa (a certain type of fish parasite),
Penpatus (non-externally segmented caterpillars), certain
insects and scorpions, the Tunticata (sea squirts), certain
sharks, certain marsupials, and of course all the placental mammals.
Berg noted: (35)
Everything
in the anatomy, embryology, and paleontology of mammals inclines
us to share Abel's opinion: the monotremata, marsupiala, and
Placentalia are three parallel branches which have arisen independently
of one another.
Berg pointed out that chlorophyl and
hemoglobin are allied substances, yet they have arisen quite
independently as life-carriers (36)
Manoilov
(37)
has discovered a reaction for the discrimination of the blood
of man from that of woman; it is remarkable that the same reaction
afforded the means of distinguishing the male from the female
sex in dioecious plants such as the maple (Acer negundo), the
nettle (Lychnis dioica), and Vallisneria.
He commented: (38)
Such a
physiological parallelism indicates that the elaboration of chemical
substances (which ultimately affect morphology as well as physiology)
is subject to certain laws.
While dealing with blood, it may be
noted in passing that C. L. Prosser, in a paper inspired by the
Darwin Centennial "celebrations," pointed out: (39)
Haemoglobins,
different in protein but similar in heme, have evolved separately
many times -- in chordates, a few molluscs, some entomostraeons,
certain annelids, numerous holothurians, a few dipteran insects,
even some nitrogen-fixing bacteria.
35. Berg, Leo, Nomogenesis:
Or Evolution Determined by Law, original Russian edition
of 1922 translated by J. N. Rostovtov, Massachusetts Institute
of Technology Press, 1969 reprint, pp.214, 215.
36. Ibid., p.224.
37. Manoilov, W. W., in The Medical Gazette, vol.15,
1923: quoted by Leo Berg.
38. Berg, Leo, Nomogenesis: Or Evolution Determined by Law,
original Russian edition of 1922 translated by J. N. Rostovtov,
Massachusetts Institute of Technology Press, 1969 reprint, p
225.
39. Prosser, C. L., "The Origin after a Century: Prospects
for the Future," American Scientist, vol.47, 1959,
p.539.
pg.9
of 14
And warm-bloodedness has, of course,
appeared twice, independently, in birds and in mammals. The transformation
of a cold-blooded animal into a warm-blooded animal involves
complexities in the central and peripheral nervous systems which
are almost unbelievably complex.
Berg
noted that in certain insectivorous plants there has developed
a fermenting agent similar to the pepsin of the animal digestive
system, to enable it to make use of protein food stuffs; and
it is secreted by a corresponding organ. (40) Yet curiously
enough, pepsin appears only in the higher animals; its presence
in invertebrates is still a matter of doubt.
Berg
referred to the development of very similarly structured bifocal
eyes in fish and in quite unrelated whirligig beetles. (41)
These bifocal eyes allow the beetle to see normally in air but
"to keep an eye" under water as well, whereas in certain
fishes, the reverse is observed. A horizontal band divides the
eye in both cases into an upper and lower portion, the lens of
one suitable for seeing in the air and the other in water. Such
a complex organ has developed twice, therefore, in total independence.
Furthermore,
as Rendle Short pointed out, (42) the eyes of the octopus are precisely
like those of most mammals including man, and this parallelism
extends to the structure of the cornea, iris, ciliary muscle
and processes, and the retina. Yet there is clearly no "evolutionary"
connection between these two types of living creatures.
Berg
noted: (43)
Eyes with
a lens are independently met with in annelid worms, arthropoda,
and cephalopoda. In the latter we meet with retina, cornea, iris,
ciliary process, and even (in some) with eye-lids.
Zawarzin (44) referred to eyes as
"a principle of structure connected with the faculty of
vision common to the entire animal world." For such a structure
with all its component parts (blood supply, lachrymal glands,
neuromuscular control mechanisms, and associated visual areas
in the brain) to have formed so many times in such diverse creatures
is surely quite beyond the power of pure chance
40. Berg, Leo, Nomogenesis:
Or Evolution Determined by Law, original Russian edition
of 1922 translated by J. N. Rostovtov, Massachusetts Institute
of Technology Press, 1969 reprint, p.223.
41. Ibid., p.221.
42. Short, Rendle A., "Some Recent Literature Concerning
the Origin of Man," Transactiions of the Victoria Institute,
vol.67, 1935, p,253.
43. Berg, Leo, Nomogenesis: Or Evolution Determined by Law,
original Russian edition of 1922 translated by J. N. Rostovtov,
Massachusetts Institute of Technology Press, 1969 reprint, p.
221.
44. Zawarzin, A. A., Studies in the Histology of the Sensory
Nervous System and Optical Ganglia of Insects (in Russian),
St. Petersburg, 1913, vi and 192 pp.
pg.10
of 14
acting
via natural selection upon random changes in the gene complex.
This is faith in miracles indeed.
Concerning
such strange phenomena as luminosity or phosphorescence Berg
remarked: (45)
The luminous
or phosphorescent organs, enigmatic as to function and origin,
developed independently in the most diverse groups of marine
fishes such as sharks (Spinax and others), in the stomiatidae,
the scopalidae, and in antennariidae, and others.
Such a remarkable defense weapon
as the ability to give a very powerful electric shock has also
appeared independently in three water-living animals: the Electric
Eel (a U.S. freshwater species), the Torpedo (widely distributed
in the oceans), and Malapterurus in Africa.
(46)
Again, speaking
of defense, quills have been developed independently by otherwise
harmless creatures such as the Australian monotreme Anteater
(locally called "Porcupine"), the true rodent porcupine
(Hystrix) that is common to Europe and North Africa, the South
American porcupine (Synetheres), also the common hedgehog, and
the small prickly Ericulus of Madagascar. (47)
In his book Animal Weapons,
discussing defense at a time of complete helplessness, Philip
Street remarked on a case of parallel development in insects
in the larval stage: (48)
Convergent
evolution, by which two completely unrelated types of animals
evolve similar structures for a similar purpose quite independently
of each other is an extremely interesting phenomenon. There is
certainly no possible connection between the various types of
tube worms and the larvae of the caddis fly, yet these larvae,
usually referred to as caddis worms, construct tubes for their
protection which are remarkably similar to those produced by
marine annelids.
So much for organs or structures:
the same picture applies to whole animals. David Lack, speaking
of the Australian fauna, said: (49)
Australia
was colonized by marsupial mammals which, in the absence of placental
forms evolved into fox-like, wolf-like, mole-like, squirrel-like,
rabbit-like, rat-like, anteater-like, and flying squirrel-like
forms, which resemble, often closely, their counterparts among
the placental mammals of other continents.
Yet they are not related to them.
45. Berg, Leo, Nomogenesis:
Or Evolution Determined by Law, original Russian edition
of 1922 translated by J. N. Rostovtov, Massachusetts Institute
of Technology Press, 1969 reprint, p.219.
46. Short, Rendle A., "Some Recent Literature Concerning
the Origin of Man," Transactiions of the Victoria Institute,
vol.67, 1935, p.253.
47. Jones, F. Wood, Trends
of Life, Arnold, London, 1953, p.80.
48. Street, Philip, Animal Weapons, MacGibbon & Kee,
London, 1971, p.37.
49. Lack, David, Evolutionary Theory and Christian Belief,
Methuen, London, 1957, p.65.
pg.11
of 14
From Sir Alister Hardy's work, The
Living Stream, the following illustrations will show how
remarkably close in structural detail such parallels may be.
(50) The desert rat and the Jerboa (see Fig. 4) are dearly
responding to environmental pressures by developing the same
exceptional overall form, which enables them to move quickly
in loose sand by jumping like a kangaroo rather than by running.
The Tasmanian wolf skull cannot be told apart from the skull
of the North American or European wolf (see Fig. 5), (51)
The range of variability in both overlaps. Even more remarkable
is the close similarity between the placental and marsupial moles
(see Fig. 6), which have developed almost identical "digging"
feet, nose and mouth configuration, eye structure, and ear openings
designed to prevent particles entering the ear hole. (52)
Yet these two creatures are not related. G. G. Simpson (53)
has given an illustration of the structural framework supporting
the wing of a bat and a fly, and believes it is another example
of convergent development to meet a shared engineering problem.
Wood Jones stated it very succinctly:
(54)
It seems
therefore certain that structures which have developed for the
satisfaction of these common needs may bear a considerable likeness
to each other, although the animals manifesting them may be utterly
unrelated by kinship or descent. Since so many basal needs are
common to all animals and these functional needs are satisfied
by the development of appropriate structures, it is to be expected
that a common ground plan of parts and organs might be detected.
. . .
Homologies are then neither due to
chance nor to descent, but to a built-in design factor.
It might be argued that we do not
have direct evidence that substantial changes in structure can
be attributed to environmental factors. But we do have
such evidence. For example the phenomenon of hornlessness in
normally horned cattle is observed when herds are moved into
areas in which hornlessness is already known. Such cattle are
found in Europe, Africa, and South America. (55) Again,
Swiss cattle moved into Hungary developed longer horns and longer
legs, such as the native cattle have. In another instance, cattle
brought from the Bavarian Alps into the crown estate of Altenburg
in Hungary not only developed the longer horns common to the
area,
50. Hardy, Sir Alister,
The Living Stream, Collins, London, 1965, p.202.
51. Ibid., p.201.
52. Ibid., p.200.
53. Simpson, G. G., The Meaning of Life, Yale University
Press, 1952, p.182.
54. Jones, F. Wood, Trends of Life, Arnold, London, 1953
p 71.
55. Berg, Leo, Nomogenesis: Or Evolution Determined by Law,
original Russian edition of 1922 translated by J. N. Rostovtov,
Massachusetts Institute of Technology Press, 1969 reprint, p.241.
pg.12
of 14
Fig. 4.
(A) The marsupial jerboa (Antechinomys laninger) and (B) the
placental jerboa (Dipus hirtipes), redrawn respectively from
Troughton's "Furred Animals of Australia" and the "Cambridge
Natural History."
Fig. 5.
The marsupial Tasmanian wolf (Thylacinus cynocephalus), with
(A) its skull compared with (B), that of the placental wolf (Canis
lupus), drawn to the same scale, from specimens in the Oxford
University Museum.
Fig. 6.
(A) The marsupial mole (Notoryctes), redrawn from the "Cambridge
Natural History," and (B) the placental mole (Tlpa europe
a), drawn from a photograph.
pg.13
of 14
but their horns became
harder and acquired a peculiar lyrelike form characteristic of
the local Hungarian breed, and the skull became narrower. (56) Such structural differences
often form the basis by which modern taxonomists distinguish
species and genera, and even higher orders of classification.
The investigators believed that these changes were entirely due
to the effects of the Hungarian climate and soil. They were not
due to interbreeding.
Fishes (Zoarees viviparus)
transferred from Ise Fjord to Roskilde Fjord in Denmark, a few
degrees of latitude, increased the number of vertebrae, the average
rising from the native mean of 108 to a higher mean of 114.6
vertebrae. (57)
The stocks did not mix with fish already in the new area. Similarly,
land molluscs of different genera have developed parallel shell
forms, markings, and decorative patterns in entire independence.
(58) The list could
be extended to the point of boredom. But it works both ways.
Unlikes may become like, and likes may come to differ -- actual
relationship or lack of it is not necessarily reflected by the
terminal result. This applies also to apes and men, though the
actual data we have shows rather that the human skull more readily
degrades towards an apelike form than that the ape skull becomes
humanlike. If size is ignored, certain now extinct apes did develop
over a long period of time, it is held, into a more manlike form
including the acquisition of partial erectness, somewhat reduced
brow ridge development, and a more humanlike tooth pattern as
a whole. Such changes are possible and may have been due to environmental
factors with secondary influences, resulting from changes in
food habits as ambient conditions modified the local fauna and
flora which comprised the food supply.
In the next chapter we shall examine
the extent to which the human skull may be "degraded"
structurally until it resembles more nearly the ape skull. Such
factors as climate, diet, and certain cultural habits which relate
to eating (the presence or absence of knives, for example) can
be shown to effect changes in cranial morphology. These brutalize
the appearance but do not provide justification, in the absence
of any other guide, for supposing that fossil men were phylogenetically
nearer to the apes than to modern man.
56. Ibid., p.280.
57. Ibid., pp.281, 282.
58. Ibid., p.247.
pg.14
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Copyright © 1988 Evelyn White. All rights
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