Darwinism and Race Progress

by John Berry Haycraft

[Darwin’s Law of Selection.]

The law of selection brought forward by Darwin and Wallace may be stated as follows:—No two offspring of the same parents are quite similar to each other, indeed they often vary to a considerable extent. Under the conditions in which they live, some of these offspring will have an advantage over the rest, dependent upon an inborn peculiarity. Inasmuch, therefore, as more progeny are produced than can ever survive, those most fitted to these surroundings will have the better chance of living. These will, in larger numbers, perpetuate the race and transmit their inborn qualities to the race, thus gradually eliminating the less suitable ones.

Keeping to the case of the giraffe, Darwin and Wallace would explain the length of the neck somewhat as follows: With Lamarck they believe that the ancestor was short-necked, but the subsequent elongation they would explain in quite another way. They would take for granted that there are times when grass and foliage are scarce, that short-necked animals would soon exhaust the herbage and shrubs, but that the taller shrubs and trees would afford subsistence to animals with a higher reach. Amongst the ancestral giraffes those born with the longest necks would at such times have an advantage over the rest, who in large numbers would die out. The longer necked ones, more suited to their environment, would perpetuate their inborn quality of long-neckedness: of the next generation those again with the longest necks would survive, and so on. The Darwin and Wallace school of thinkers would, I quite believe, be prepared to state that by attention to education it would be possible to improve the mental qualities of the race, but they would teach that this improvement could only take place provided that the system made it possible for the clever man and woman to earn a better livelihood, marry early, and have large families, while the stupid ones should produce fewer children, a condition which at present is far from being the rule.

Fig. 1.

Diagram to illustrate: A, the transmission of acquired characters, B, modification of type by natural selection. In A an individual of rounded proportions, at the top of the diagram, has two children. Environment is represented by a board with holes through which they must pass. In so doing they become thinner, transmit the thinness to their children, and so on. In B, a man of rounded proportions has two sons who vary, one being fat, the other thin. The fat one cannot get through the hole in the board; but the thin one does, has children who again vary, the thin one having an advantage.

[Three Ideas involved in Selection.]

Now there are three ideas in this law of natural selection: first, that there are inborn variations among the offspring even of the same family; secondly, that these various individuals living in surrounding conditions on the whole uniform and common to all of them, will start in life, some with an advantage and others with a relative disadvantage, and that those possessing an advantage will, more of them, tend to produce offspring; thirdly, that the variations, inborn in this case and not acquired, will probably be transmitted. That there are marked variations—physical, mental, and moral—among a litter of kittens or puppies is within the experience of everyone who has kept them, and that variations in human families are as marked is known to everyone who has brothers and sisters. Even twins frequently differ considerably from each other, and it is said that the last years of the lives of the Siamese twins were sadly marred by their opposing views as to the rights and wrongs of the American Civil War! It stands to reason also that these variations may be of advantage or disadvantage to their possessors, and that among animals and plants, where there are no social props given to the weak, the variations may and do determine survival. To give an idea of the rigorous operation of selection which we find among the lower animals, we have only to enumerate the number of the progeny produced by each pair, which is often prodigious, and knowing as we do that the number of individuals in a species remain virtually the same in a given district for long periods of time together, we conclude that the room of the parents is just filled by a younger pair, and all the excess of their progeny over and above this one pair must have succumbed to surrounding want and hardship. To give one concrete example out of hundreds that might be selected, let us take the case of the golden eagle given by Weismann in his essay on the “Duration of Life.” He says: “Let us fix the duration of life in the golden eagle at sixty years, and its period of immaturity (of which the length is not exactly known) at ten years, and let us assume that it lays two eggs a year, then a pair will produce one hundred eggs in fifty years, and of these only two will develop into adult birds, and thus on an average a pair of eagles will only succeed in bringing a pair of young to maturity once in fifty years; and so far from being an exaggeration, this calculation rather under-estimates the proportion of mortality among the young.”

But in all probability most of us are more conversant with the ways of the domesticated cat than with those of the golden eagle. The cat produces its first litter of three or four before it is a year old. Its kitten-producing life lasts, say, for eight years, and it may, on a low estimate, be supposed to produce a litter of four kittens once in each year. In all a cat will have, on a fair estimate, thirty-two kittens, and may be a great-great-great-great-great-great-grandmother in her lifetime, yet we do not observe in town or village such an alarming increase in the cats from year to year. Their number is pretty stationary, kept so by the enormous destruction of their progeny. The enormous capacity for reproduction of a race of animals, where for a time their surroundings are favourable, will be appreciated by the lowland farmers whose fields were laid waste a few years ago by armies of short-tailed field-mice, whose natural enemies, the hawks, the cats, and the weasels, had been extensively shot or trapped.