Evolution: An Investigation and a Critique

by Theodore Graebner

In all the domain of natural science there are no wonders more amazing than those of instinct. The subject is simply inexhaustible. Moreover, every animal is absolutely dependent on instinctively performed actions and habits. The life-story of many wasps, of the various ants,—someone has called the brain of the ant the most wonderful speck of protoplasm in the world,—and of the insects generally, is bound up with instincts that partly interlock marvellously with the life-story of plants, and which are, even viewed in themselves, the greatest wonders of creation. The questions insistently call for an answer: How could these instincts preserve the animal when they were still in an incipient, undeveloped state? How could they arise through natural selection (which is simply accident, of course), at all? Darwin says that there are instincts "almost identically the same in animals so remote in the scale of Nature, that we cannot account for their similarity by inheritance from a common progenitor, and consequently must believe that they were independently acquired through natural selection." Again he says "Many instincts are so wonderful that their development will probably appear to the reader a difficulty sufficient to overcome my whole theory."

And here, in the vernacular of the day, we would depose that Mr. Darwin "said something."

CHAPTER SEVEN. Heredity.

The subject of heredity is intimately bound up with the evolutionary hypothesis and, it must be admitted, creates a new difficulty for the acceptance of the theory. Indeed, the laws of heredity, so far as understood, appear to contradict the theory of Lamarck and Darwin at a vital point, if not at the vital point of the entire structure raised in the "Origin of Species." It is necessary in order to appreciate the strength of this objection, to recall once more the outstanding features of the hypothesis by which scientists have attempted to account for the variety of living forms. The various theories of organic evolution, whether Lamarckian, neo-Lamarckian, or Darwinian, are based upon the assumption that animals and plants have a tendency to perpetuate by transmission to offspring a variation which has proven useful as an aid to the particular species in its struggle for existence. We have just discussed, in the chapters on the Fixity of Species and on Rudimentary Organs, certain difficulties which loom up when the question is raised, How did varieties become distinct species? However, even if it were to be assumed that some satisfying answer might be found to this question so far as the stages of incomplete organs are concerned, there is one fact in heredity which, it would seem to me, strikes at the very heart of the theory.

In his "Philosophic Zoologique" (1809), Lamarck first explicitly formulated his ideas as to the transmutation of species, though he had outlined them as early as 1801. The changes in the species have been wrought, he said, through the unceasing efforts of each organism to meet the needs imposed upon it by its environment. Constant striving means the constant use of certain organs, and such use leads to the development of those organs. Thus a bird running by the sea-shore is constantly tempted to wade deeper and deeper in pursuit of food; its incessant efforts tend to develop its legs, in accordance with the observed principle that the use of any organ tends to strengthen and develop it. But such slightly increased development of the legs is transmitted to the offspring of the bird, which in turn develops its already improved legs by its individual efforts, and transmits the improved tendency. Generation after generation this is repeated, until the sum of the infinitesimal variations, all in the same direction, results in the production of the long-legged wading-bird. In a similar way, through individual effort and transmitted tendency, all the diversified organs of all creatures have been developed—the fin of the fish, the wings of the bird, the hand of man; nay, more, the fish itself, the bird, the man, even.

Note well, the fundamental assumption is that such acquired characteristics,—greater length of leg, or of neck, a coating of hair, a protective coloring, etc.,—however acquired, can be transmitted from the parent animal possessing them, to its offspring. The question arises: Can such characteristics be transmitted? And the students of heredity answer: They cannot!

I find in G. Archibald Reid "Alcoholism, a Study in Heredity," a lucid exposition of this subject. (Reid is a F. R. S. E. His book was published by T. Fisher Unwin, London, a few yars [tr. note: sic] ago.)

"All the characters of a living being, every physical structure and every mental trait, may be placed in one of two categories. Either they are inborn or they are acquired. An inborn or innate character is one which, in common parlance, arises in the individual 'by nature.' Thus arms, legs, eyes, ears, head, etc., and all inborn characters. The child inherits them from his parent. But, if during its development, or after the completion of the development any one of the inborn characters of an individual is modified by some occurrence, the change thus produced is known as an acquired character, or, shortly, as an acquirement.

"Thus all the effects of exercise are acquirements; for example the enlargement which exercise causes in muscles. The effects of lack of exercise are also acquirements; for example, the wasting of a disused muscle.

"The effects of injury are acquirements; for example, the changes in a diseased lung or injured arm. Every modification of the mind is also an acquirement; for example, everything stored within the memory.