Vernon L. (Vernon Lyman) Kellogg.

Darwinism to-day; a discussion of present-day scientific criticism of the Darwinian selection theories, together with a brief account of the principal other proposed auxilary and alternative theories of species-forming online

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Online LibraryVernon L. (Vernon Lyman) KelloggDarwinism to-day; a discussion of present-day scientific criticism of the Darwinian selection theories, together with a brief account of the principal other proposed auxilary and alternative theories of species-forming → online text (page 5 of 38)
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origin of adaptations, since all specific characters are really

"But on the other hand, many naturalists think that there
are specific characters for which we cannot only see no
utility, but which are demonstrably of no use. A few illus-
trations will serve to make the matter clearer. Certain in-
sects are distinguished from each other in accordance with
whether they possess one or two bristles on the head. Here
is a character which appears to be constant, and which must
therefore be explained by any complete theory of the origin
of species. Can we imagine that the question of whether
the animal has one or two hairs should ever have been of
selective value? But if developed by natural selection, this
character must at some time have been a matter of life and
death. Again among snails, the shells commonly coil in
the same direction in the same species, this fact making the
direction of the coiling of the shell a specific character. But
clearly this is not a matter of selective value, since living
among the rest of the individuals will frequently be found
some with their shells coiled in the opposite direction.
Again, horses have small horny callosities on their feet. No
one has suggested any possible use for them, but neverthe-
less they are present on the feet of all the species of the horse
family. But the most curious fact is that while the horse has
them on all four feet, the ass has them on only two. Now,
upon the principle that utility is universal, it would be neces-
sary to claim, not only that the presence of four callosities
has been a matter of selective value in the horse, an ex-
tremely difficult thing to believe, but also that the presence
of only two instead of four has been of selective value in the
ass. This position approaches absurdity. Again, there are
molluscs characterised by special markings of the shell,
which markings are constant enough to be specific char-
acters, and must, of course, be included in any explanation


of the origin of species. But these marks are demonstrably
of no use, since they are entirely covered by the epidermis
of the animal when alive, and absolutely invisible. Again,
some birds have slight differences in colour markings which
separate species. Now these differences may perhaps be re-
garded as of use as protective or as recognition marks.
But in some cases the colour markings are entirely con-
cealed by other feathers and, being invisible, can be of no
possible utility. It is hardly possible for one, unless he has
decided previously to accept the all-sufficiency of natural
selection, to believe that there can be any utility in the very
slight differences in the shape of leaves of plants, in the micro-
scopic markings of the hairs of different species of mammals,
the exact numbers of the feathers in the tails of birds, the
peculiar distribution of the veins in the wings of a butter-
fly, the microscopic markings in the scales on its wings, or
a host of other similar trivial characters. When it is re-
membered that the selection principle would force us to
insist that all of these characters are of value sufficient to
protect their possessors at the expense of other individuals
not possessing them, it is evident that the burden thrown
upon the principle of survival becomes very great. When
finally we come to characters of specific nature connected
with colour markings which are invisible when the animal
is alive, there is apparently no resource left except to con-
clude that the principle of survival because of utility does
not account for everything."

It is indeed the general recognition by naturalists of the
fact of the triviality or indifference of a majority of specific
characters that has led to the recent renewal of the import-
ance of isolation theories, particularly of geographical
isolation. The rehabilitation of Moritz Wagner's theory of
species-forming by migration and isolation is a conspicuous
feature in present-day evolution discussion. The way in
which isolation comes to the aid of selection, or even sup-


plants it in the minds of some, in species-forming is pointed
out in chapter ix, to which the interested reader may

But in those cases where the differences or variation

among individuals may be or obviously are of the character

The swamping of useful ones, and where by comparing ex-

or extinguishing tremes o f this variation the life-and-death-

of favourable va-
riations by inter- determining worth of this utility might be
breeding. conceded, still what chance is there for the

perpetuation of this advantage? Nageli long ago pointed
out that the extreme variations, that is, the rare variations,
would in almost every case be inevitably extinguished by
interbreeding. If a certain considerable variation occurred
in one individual of a hundred born, in 20,000 individuals of
the species 200 would have this worth-while variation.
Now if the chances of mating are the same for all there
would be 9,801 parings of individuals not showing the
variations, 198 pairings between a varying individual and a
non-varying one, and a single mating between two indi-
viduals both preserving the considerable variation. In fact
every rare variation will, as Delage says, be immediately
effaced by the dilution of the blood of the varying individual
by that of the great mass of individuals not possessed of the
particular variation. This inevitable swamping of the ad-
vantageous variations of individuals has long ago led to the
practical giving up by Darwinians of any claims to species-
forming or evolution on the basis of extreme or rare varia-
tions and to the restriction of the selecting influence to
masses. The species must be changed through the selection
of it as a mass or unit rather than through the selection of
special scattered individuals of it.

But for the selection of masses of individuals sufficiently
considerable to avoid the extinguishing of the fortunate
variations by interbreeding, and to insure a repetition of
the advantage and an opportunity for its fostering and


increase, there is necessary an extraordinary coincidence in

the appearance of the needed variations in many forms at

The needed co- the right time. That is, a theory based on chance

incident occur- or accidental phenomena demands after all the

rence of several

variations at one assumption of the occurrence of phenomena
time> of the right kind at the right moment, and

the persistence of such occurrences through a definite
time-period. This is too much to assume, too much to ask
even of those of the true faith, say the antagonists 1S l4 of
the selection theory. Kronig 15 makes sport of the selection
doctrine by having his rather frivolous character, Sabuch-
winski, undertake to have made, by a foolish clown, various
trifling changes in all kinds of industrial products with the
expectation of bringing them into the market. He is con-
vinced that he will win a fortune by this, for he says to
himself that the struggle for supremacy must work out the
same in the industries as in nature, and in his case with the
added advantage that the changes effected by even the most
slender-witted boor must result better than those which are
the outcome of perfectly blind chance. Indeed, from the
very heart of the neo-Darwinian ranks come signs of dis-
may when this objection is faced. Weismann, leader of the
ultra-selectionists, practically concedes the irrefutability of
this objection to the Allmacht of selection when he intro-
duces a statement of his latest theory, that of Germinal
Selection, by saying: 18 "Knowing this factor [that of germi-
nal selection] we remove, it seems to me, the
ie patent contradiction of the assumption that the
general fitness ' of organisms or the adaptations
necessary to their existence are produced by
accidental variations a contradiction which formed a seri-
ous stumbling-block to the theory of selection." And the
formulation of the theory of germinal selection is of itself
a practical confession on the part of the foremost neo-
Darwinian of the inability of natural selection to explain


species-forming without calling to its aid some effective
factor to control in its beginnings the variation essential
as the basis of the selective action.

Pfeffer 1T and Wolff 18 have been particularly keen and
severe in their criticism of the selection theory on the basis
of this objection. And Morgan 19 in this country has also
made effective use of this weapon in his destructive con-
sideration of the Darwinian theories.

There is an additional point about this difficulty of the
necessity for a certain regularity or reliability of variation
. . in order to make a beginning basis for the action
coincident ap- of selection. It is this. Close scrutiny reveals
?Sation S to ther the necessity often of the occurrence of several
make a certain coincident variations in order to make any one
characteristic positively advantageous. What
advantage in the way of increased speed is a slight added
length of leg without a simultaneously added strength of
musculation ; or an increase in size of antlers without a
simultaneous increase in strength of neck muscles to sup-
port and manipulate the heavier head? What faint prob-
ability of the occurrence coincidently of the necessary varia-
tions (if determined only by chance, that is, the law of prob-
ability) to produce a gradual perfecting of so complex
a structure as the vertebrate eye? Or, more, how incon-
ceivable the coincidences, if variation is purely fortuitous,
necessary to the simultaneous development of two exactly
similar eyes: two eyes so intimately associated physio-
logically that normal sight is a function of both these
separated organs working perfectly together. Is variation
to be assumed to be governed by some law of bilateral
symmetry? But I have shown for many cases J0 that in such
perfectly and fundamentally bilaterally symmetrical animals
as insects neither the usual Darwinian fluctuating variation'
nor the rarer discontinuous or sport variation is governed
at all by such a law. In fact the independence of the varia-


tion phenomena in right and left members of bilaterally
arranged pairs of organs as wings, antennae, legs, etc., is a
noticeable fact. This denial of the capacity of the selection
of fortuitous slight variations to account for coadaptation
and for the continuous perfecting of complex organs has
been stated as follows : "It is highly improbable that for the
steady perfecting of an organ, the variations needed by
selection will always appear just at the right time." Or in
more expanded form : "It is highly improbable that during
the modification of a complex organ such as a whole body
part, or during the gradual perfecting of an adaptive modi-
fication, the numerous necessary variations will appear suc-
cessively in such series that a harmonious combination of
the single variations will be possible." The objection cer-
tainly needs no elaboration. The Darwinian variations ap-
pear in all directions at all times in slight degrees with no
determinate direction nor correlation. Selection is to find
in these variations its only material with which to build up
to wonderful complexity and perfection of coadaptation
and correlation of parts 21 on a basis of constant advantage,
such an intricate but harmoniously adjusted compound organ
as the human eye, in which the failure or imperfectness of a
single minute part can at any time, during the course of
development, rob the whole of any advantage whatever to
the organism possessing it.

Wolff C2 enlarges on the difficulty of explaining any

identical structures of the animal body which appear in one

Difficulty of an ^ the same organism to the number of two

explaining re- or more. "It cannot be explained," he says, "by

peated identical ,

structures by selection, how the carnivores, for example, can
selection. have developed through fortuitous yet always

similar variations, two such structures agreeing in all de-
tails as the back teeth, which have developed in course of
time from small skin teeth. That a tooth can develop into
such an admirable biting organ through chance variation may


be explicable by selection, because we are accustomed to
postulate thoroughly fortuitous and all-inclusive variation ;
but that the tooth standing next to it shall have varied al-
ways in exactly the same way so that the result of its de-
velopment shall make it identical with the other one, is
inexplicable by selection on a basis of fortuitous variation,
but rather indicates that the change of form is ruled by law
which we do not know. The attempt to discover it is the
most imperative task for biologists to undertake."

Wolff " follows this argument farther by discussing other

particular examples, but they are all of the type of the one

Spencer's pic- J ust set out - Spencer pictures the situation of

tare of the inu- th e herbivorous animals in a country of in-

tility of advan-
tage in a single clement climate and populated by numerous
direction. carnivores. Now those herbivores which have

the finest hearing will be soonest aware of the approach of
the tiger, but those with keenest sight or most perfect sense
of smell will also perceive, as soon, that it is time to flee. But
what advantage over others will the first start in flight give
them? Others less delicately endowed with sense organs
but swifter of foot will, although starting a little later, have
as good a chance to escape because of their more rapid run-
ning. Later may come snow and terrible cold. Those in-
dividuals best endowed with sense-organs or swiftest of foot
will not necessarily be the most enduring or the best
equipped with instincts to find shelter. The climate may
decimate those which selection on the basis of special senses
or speed has saved. But after the cold may come the sum-
mer drought. Those most heavily furred or warmest-
blooded which have successfully endured the low temperature
and snow and ice of winter should be the first to suffer from
the attacks of sun and drought and lack of food in the
summer. Thus no individual has, because of advantage in
any one character, any real and complete superiority which
guarantees it success in all the phases of the struggle for


existence: the advantages are scattered and compensated
by disadvantages. 24

In connection with the objection stated in the preceding

paragraphs is that specially pressed by Wolff, although long

Numerous use- a & strongly stated by Mivart, 25 and one that

ful charaoteris- } ias loner appealed strongly to me particularly in

tics useful only S ^ *

in highly per- connection with the study of the utility of
fectedsjate. colour and pattern among insects. This ob-
jection is, that numerous useful characteristics or adapta-
tions of organisms are useful only in a highly perfected
state, often involving a complex and considerable structural
development of old (then much modified) or quite new parts,
and hence could not have arisen by gradual modification by
the selection of slight variations. Darwin himself says that
if a single complex organ can be referred to whose full de-
velopment cannot possibly be explained through numerous
small successive modifications, then his theory must indubi-
tably fall. For example, the electric organ of the torpedoes,
the brood-sacks or cells on the back of Pipa dorsigera, the
chameleon's tongue, and many other organs can be recalled
which could not possibly exercise their particular advanta-
geous function in an undeveloped and beginning state. In
my own eyes has for long stood the familiar case of the
mimicry of our common American monarch butterfly,
M . . . Anosia plexippus, by the viceroy butterfly,
Anosia by Basilctrchia ar chip pus. The viceroy belongs to a
!hia> group of species in which the prevailing (almost
certainly the ancestral) colour and pattern are white and
black (or iridescent purplish and bluish) arranged as a broad
white continuous transversal bar across both fore and hind
wings, on a black (to purplish) ground. The colour and
pattern of Anosia are radically different; brick-red ground,
black longitudinal lines following the veins and small white
spots in an irregular black submarginal band. Examine the
viceroy butterfly. You find no suggestion of typical Basi-


larchia type of colour and pattern ; on the contrary, you
find an extraordinarily faithful imitation (duplication) of
Anosia's colour and pattern. Only in a narrow black trans-
versal streak across the outer disc of each hind wing is there
any divergence in the viceroy from the Anosia pattern.
Now Anosia is distasteful to birds ; after a few experiments
with Anosia a bird recognising this ill-tasting morsel in its
conspicuous red-brown livery leaves the monarchs alone. Not
only monarchs, however, but also viceroys, which are to all
external seeming only slightly smaller monarchs. The viceroy
is, however, not distasteful; it would be a welcome bonne
bouche to any bird that could distinguish it. But thanks to
its perfectly mimicking colour-pattern it wings its deceitful
way unmolested. There is huge usefulness here, and selec-
tion can well be the steadfast maintainer of the viceroy's
dissimulation. But of what avail for this purpose of deceit
was the first tiny tinge or fleck of red-brown on the staring
black and white wings of the ancestral viceroy? How can
one possibly conceive of an attainment of this identity of
pattern between mimicker and mimicked by selection on a
basis of life-or-death-determining advantage of slight chance
appearances of brown or reddish flecks or tinges in suc-
cessive viceroys? Not until practically full development of
the mimicry pattern existed can this pattern have worked its
advantage. It is, indeed, a different matter with many, per-
haps most, cases of general or special protective resemblance.
A little green, a little brown could obviously help the insect
living in green foliage, or on the ground. Every change of
tinge toward the general environing colour is worth while ; it
helps melt the insect into its inanimate surroundings. But
with mimicry it must be the whole thing or nothing; or at
least near enough to the whole thing to pass for it. Wolff
puts the objection about as follows: There are compound
organs and complex adaptations, whose complication (he
would better say, whose advantage due to complication) cart


only be reached by a leap, while the selection theory pre-
supposes slight gradual stages of complication.

Wolff 28 expresses another phase of this objection by re-
ferring to a few of many cases of complex relations between
Difficult of entirely distinct organs in the body, which
explaining com- relations constitute some of the most important
Songtdy^ functions of the body. For the successful
parts,by selec- establishment of these relations it has been
necessary, as Wolff expresses it, "that for each
advance in development or complexity of one definite pecu-
liarity in an organ there must appear corresponding and
exact definite advance in development or complexity of a
peculiarity in another entirely distinct organ." Wolff's first
example is the relationship existing between the muscles
and nerves of the higher animals. The intimate, delicate,
and precise character of the relations between the nerve-end-
ings and the muscle cells, to be explicable by selection of
fortuitous variations, must have required coincident varia-
tions both in structure and functions of each muscle cell and
each nerve-ending that are impossible to conceive of. "It
might be," says Wolff, "possible to picture the gradual
development of the relations between one muscle cell and
one nerve-ending on the basis of a selection among infinitely
fortuitous variations, but that such variation shall occur
coincidently in time and character in hundreds or thousands
of cases in one organism is inconceivable."

In the case of organs whose functions are regulated from
a common centre, the development of centre and of organs
must have gone on coincidently and could not have been
independent. The development of the eye is useless if
the development of the optic centre did not go hand in
hand with it. Without the one the other has no reason,
no significance, therefore selection could have brought
neither to its proper development independently. The
coincident appearance, however, of organ and centre can


be explained by the selection theory only when there is
postulated a definite degree of complexity of the fortu-
itously appearing slight variations, that is, when this
theory is in condition to assume that which would be a
denial in terms that variations are wholly fortuitous.
Wolff goes on to give certain examples of such complex
relations which involve a dependence of the use upon an
instinct, as the performance by the queen honey-bee of her
particular functions in the hive, etc.

"Out of this discussion,'' says Wolff, "finally we must
postulate that structures which are to be explained by the
selection theory must possess at the least two certain charac-
teristics. Such a structure, namely, must occur but once
in an organism [that is, must not be a serially or bilaterally
repeated organ, nor indeed appear in any condition of plural
number] ; further, it must not stand in any necessary relation
to any other part of the same organism, that is, in a relation
which one can interpret as a relation not existing from
the beginning, therefore one which must be looked on as an
acquired relation. But if we survey the whole animal king-
dom it will be very difficult for us to find any structures
which satisfy both these requirements. It might be possible
to find some which perhaps seem to satisfy the second re-
quirement, but with regard to the first requirement I may
declare," says Wolff, "that there is scarcely a single structure
which fulfils it. Symmetry alone, which rules almost all
organisms, makes organs which appear in the singular num-
ber rarities, and even such as the pancreas, etc., are com-
posed of many finer structures, which are homodynamous
among themselves. When we find two similar organs in
different animal groups we seek for a causal explanation of
this similarity and find it in common ancestry. It is absurd
to seek a causal explanation for the origin of homologous
structures and yet postulate a purely chance or fortuitous
explanation for the origin of homodynamous structures."


Another objection which the study of the utility of col-
our and pattern " also has impressed upon me is that of the

OVection based Cari 7 m & to ^ ar f certain lines of modification.
on over-speciali- Classic examples are the fatal over-development
of the antlers of the extinct Irish stag, the un-
wieldiness of the giant Cretaceous reptiles, the intimate
identity of the halves of bilaterally symmetrical animals.
Let me call attention to an overdone case of "protective
resemblance" among the insects. It is that of the famous
Kallimas, the dead-leaf butterflies of the Malayan and gen-
eral south tropical regions. These butterflies (there are
several species which show the marvellous imitation) have
the under sides of both fore and hind wings so coloured and
streaked that when apposed over the back in the manner
common to butterflies at rest, the four wings combine to

Kallima, the resemble with absurd fidelity a dead leaf still
de^-l-leaf butter- attached by a short petiole to the twig or branch.
I say absurd, for it seems to me the resemblance
is over-refined. Here for safety's sake it is no question of
mimicking some one particular kind of other organism or
inanimate thing in Nature which birds do not molest. It is
simply to produce the effect of a dead leaf ; any dead leaf ;
a brown, withering leaf on a branch. Leaf-shape and gen-
eral dead-leaf colour scheme are necessary for this illusion.
But are these following things necessary? namely, an
extraordinarily faithful representation of mid-rib and lateral
veins even to faint microscopically-tapering vein tips ; a
perfect short petiole produced by the apposed "tails" of the
hind wings ; a concealment of the head of the butterfly so
that it shall not mar the outlines of the lateral margin of the
leaf; and, finally, delicate little flecks of purplish or yellow-
ish brown to mimic spots of decay and fungus-attacked spots

Online LibraryVernon L. (Vernon Lyman) KelloggDarwinism to-day; a discussion of present-day scientific criticism of the Darwinian selection theories, together with a brief account of the principal other proposed auxilary and alternative theories of species-forming → online text (page 5 of 38)