The value of the evidence of the palaeontologist—Comparative anatomy—Five fingers within the flipper of a whale—The same within the wing of the bat—The anatomy of man and the horse compared—Origin of the unicorn—Before Darwin—Darwin's great book—Violent opposition—The origin of man—Our forty-second cousins—Some highly trained apes—Could apes evolve into men?—Natural selection—The survival of the fittest—Eugenics—Heredity and variation—Mimicry—Embryology—The latest stage of man's evolution
In the preceding chapter we have seen what the palaeontologist has to say concerning the evolution of animals and man. Picturing the paleontologist as a witness giving evidence, we could imagine the opposing counsel pointing out that this evidence is merely circumstantial. It is true that the more simplified forms of animal life are found the farther down we can read into the hidden history of our globe, but it does not follow necessarily that the more complex has been evolved from the more simple. It might be maintained that there have been successive periods of separate creation. It might be pointed out also that only a very small number of the total animals have died in circumstances likely to lead to the preservation of their remains. Further, that man has merely scratched the surface of the Earth at a very limited number of places, and that therefore the evidence gained is not sufficient to warrant a general statement. Those who have studied the case carefully would not be willing to take this view. However, all will admit that the evidence of the palaeontologist corroborates the evidence of the zoologist and the physiologist.
The zoologist, by a careful comparison of the forefoot of the horse, the wing of the bat, the flipper of the whale, and the hand of man, has discovered that all these apparently different organs are in reality extremely like one another in their structure; indeed, we can trace the finger bones and joints in each case. It becomes evident that all these animals have descended from one common ancestral form.
Those of us who in our boyhood sought to know something of the doctrine of Evolution may remember some particular evidence which appealed to us as conclusive. Probably one of these proofs was the fact that the flipper of the whale had within it a series of bones exactly like a human hand. If the Creator had made a special creation of the whale, surely He would not have arranged, within the flipper, this complex structure of bones which, embedded there, could not serve any useful purpose. The accompanying diagram represents the bones within the whale's flipper and those within the human hand.
No one would suggest that these two structures were not definitely connected, and it is reasonable to suppose that the two structures have been evolved from some common stock.
Fig. 3. The Flipper of a Whale; the Hand of a Man
The close resemblance of the bones buried in the flipper of a whale to those within our own hands is very obvious.
In many other animals and in man himself we find traces of organs which serve no useful purpose. We feel justified in saying that these are relics of some bygone ancestor, and having fallen into disuse, owing to new environments, the organs are disappearing very gradually. Many people must wish that the vermiform appendix in man had been disposed of already by nature, as its presence is a great source of trouble in its present stage of evolution, giving rise to the too-well-known disorder called "appendicitis."
Again, the wing of a bat has five finger bones, four of which go to form the framework of the wing, while the fifth, the thumb, remains free and is provided with a strong nail. The general arrangement of the finger bones within the wing will be seen clearly in the accompanying diagram of the bat's skeleton.
Fig 4. The Fingers in the Wings of a Bat
The above represents the whole skeleton of a bat. It will be observed that four fingers go to make the framework of each wing, while the fifth finger acts as a claw at the top of each wing.
If we examine the anatomy of a horse with that of a man, we must be impressed with the great similarity of structure. Any person visiting the Natural History Museum in London has a good opportunity of making such a comparison. Here we find the skeletons of a horse and of a man placed side by side, and showing all the corresponding bones similarly numbered.
These facts have all been discovered within recent times.
In the so-called good old days of our great-grandfathers they had very little knowledge of the animal world. They had no menageries or zoological gardens in which they could see strange animals. They were dependent upon the tales of travellers, and how very far from the truth their imaginations could carry them is well evidenced in the picture of the unicorn. While it is true that there is no unicorn such as represented, the artist did seek originally to represent a real animal as described by a traveller.
This traveller, while on a visit to South Africa, sent home the description of a strange animal which he had seen. It is evident that his powers of description were not very great, for it was a rhinoceros which he endeavoured to describe. He wrote that he had seen an animal about the size of a horse and with a single horn on its face. It so happened that the narwhal had been discovered in the Mediterranean about that time, and a specimen of its long horn-like sword had been sent to this country. The artist drew a picture of a horse and placed this newly discovered horn on its forehead, thinking that he representing what we know now as the South African rhinoceros.
It will be of interest to note very briefly how the discovery of Evolution came about. Of course, the name of Charles Darwin is very prominent in our minds in connection, but we know that the idea did not originate with him, nor in his day. The idea of Evolution goes back much farther than the unscientific person imagines. Away back some two thousand five hundred years ago it was suggested that the different creations had been evolved one from the other, but there were no observed facts brought forward to support this idea. These proofs were not forthcoming until last century.
Our grandfathers who lived in the first half of last century were not prepared to accept the doctrine of Evolution. Even to-day there are some good-hearted folk who refuse to admit the truths of Evolution, but surely in no such case can there have been a serious study of discovered facts! The Evolutionist is not an Atheist. Because we believe that we have discovered the plan of creation we need not seek to drive the Creator from His Universe, nor to deprive man of his soul.
So long ago as one hundred years the great French naturalist Lamarck declared that each kind of animal had been evolved from a simpler type or species. He was bold enough to include even man himself in this theory of Evolution, but he had not sufficient facts to prove his theory to be correct.
A few years ago the whole scientific world celebrated the one hundredth anniversary of the birth of Charles Darwin, and to-day we have some of his sons among us, each of them actively engaged in the furtherance of Science.
It was Darwin who proved a true case for the doctrine of Evolution. He did not give his ideas to the public without long consideration, nor did he even make up his own mind in any hasty manner. In the Introduction to his Origin of Species he tells us how the ideas of the causes of Evolution occurred to him during his voyage as Naturalist on board H.M.S. Beagle. He thought that something might be made of these ideas "by patiently accumulating and reflecting on all sorts of facts which could possibly have any bearing on it." Then he adds: "After five years' work I allowed myself to speculate on the subject." It is evident also that Darwin did not desire to stir up strife concerning the origin of man, for in the Introduction to his later book, The Descent of Man, he says: "It seemed to me sufficient to indicate, in the first edition of my Origin of Species, that by this work light would be thrown on the origin of man." Indeed, his only reference to man occurs in the following short sentence on the second last page of his great book. Referring to future researches he says: "Much light will be thrown on the origin of man and his history." Yet the very suggestion of such revolutionary ideas met, not unnaturally, with vigorous opposition, but Darwin felt confident that the truth would prevail in the end. Our present interest is to consider the discovery of the facts upon which the theory of Evolution is built.
The naturalists before Darwin's days had been busy classifying the different animals and plants. The classifications were very elaborate, and were put down in the form of a tree with multitudinous branches, not that they believed it to be in reality a family tree. In this picture we see a short tree trunk representing the very simplest forms of organisms of which they had any knowledge; so simple a form of life that it would be difficult to say that they were either plants or animals. Then this short trunk divides off into two separate branches, one representing the vegetable kingdom and the other the animal kingdom. These branches again subdivide into smaller branches representing family groups, and finally there are the leaves which represent species. The very appearance of this pre-Darwinian tree would seem to us now to be a clear indication of Evolution.
Our particular interest is "Whence came man?" Some might prefer the question to be put in this way: Whence came these bodies in which we live, and which we must leave behind us some day? Our bodies share a common structure with the animals, and are governed by similar physiological laws, yet self-conscious man, possessed of a moral sense, stands apart from all other created beings.
In one sense we may say that it is ridiculous to speak of men as having been evolved from monkeys, or from such anthropoid apes as we know in these days. Looking at other branches of the tree of Evolution, we may say that we are no more descended from monkeys than from our "forty-second cousins twice removed." Yet there is no gainsaying the fact that not only the anatomy, but the physiology of man is extremely like that of the anthropoid ape, even the arrangement of the blood-vessels and the reaction of the blood itself rendering the apes liable to human diseases from which all other animals are immune. The teeth of the ape and those of man are very similar, and yet different from those of other animals. Man's body is still covered with a coating of very fine hair, and if one examines the hair on the outer part of the forearm, it will be observed that the hair grows in a direction backwards from the wrist. This is the case also with apes, and is believed to be due to these animals placing their arms over their heads to shelter them from the rain-storms in those primeval days.
The author remembers being present many years ago when the late Professor Henry Drummond was inspecting a regiment of boys at drill. He asked all the boys who could move their ears to and fro to do so. He was amused how proficient some of the boys were in this long-lost art. He then told them how this was a relic of long-past ages, when our animal ancestors required to move their long ears to and fro, and then he proceeded to expound to them the meaning of Evolution, pointing to Christian morals as he went along.
We have seen in the preceding chapter that the palaeontologists find it very difficult to determine whether some of the fossil remains found in the Earth belonged to man or to the ape. For the purpose of entertainment a few apes have been trained to imitate man, wearing clothes, eating and drinking from ordinary dishes, paying the waiter from a purse, using a toothpick, smoking a cigarette, undressing and going to bed, blowing out the candle, and so on. One of the trained apes has a bedroom in the hotels, and is treated as though he were a man. But no one would suggest that any amount of training would ever cause an ape to evolve into a man. The evolution of man has taken not only thousands, but millions of years, and the special circumstances which gave rise to the appearance of man have passed.
But we are not to suppose that the evolution of man came about as the result of blind forces. Alfred Russel Wallace, the great evolutionist and contemporary of Charles Darwin, has said: "I admit that such forces and such rudimentary mind-power may and probably do exist, but I maintain that they are wholly inadequate, and that some vast intelligence, some pervading spirit, is required to guide these lower forces in accordance with a preordained system of Evolution of the organic world."
Darwin's theory was based upon what he called "Natural Selection," the meaning of which is perhaps more easily grasped from another name which was suggested by Herbert Spencer, this title being "The survival of the fittest." Has it not become an axiom that "the weak must go to the wall"? In these modern times the fit are endeavouring to enable the unfit to live also. The unfortunate thing is that the unfit are multiplying at a much greater rate than the fit. The result of this will be that our race will deteriorate unless some way out of the difficulty can be found. It is to this end that the Science of "Eugenics" has been set on foot within the last few years. Those who are taking an active part in the work of these Eugenic Societies are doing a noble and far-reaching work. This work will be helped greatly if the rising generation will make a serious study of the Sciences of Zoology and Evolution.
We need not trouble about the laws of heredity and variation, but in these present days of scientific horse-breeding we have ample demonstration. Occasionally a specially bred horse will fetch as large a sum as four thousand guineas. This has been arrived at by mating together horses having the finest qualities. The same has been done with other animals. One farmer desires some particular quality in sheep, and in course of time he is able to rear sheep with that particular quality exaggerated, while another farmer has raised a breed of sheep exhibiting some other desired quality. These special species have been arrived at under the guidance of man, but they will serve as analogies for "Natural Selection."
Darwin saw that if all the animals which are born into the world should live, and each pair have a family equally numerous, there would be an enormous population of these animals in a comparatively short time. What does happen in reality is that one pair is represented in a later generation by another single pair or thereabouts. It is self-evident that in nature it will be the fittest that will survive.
This survival of the fittest has led to some very interesting results. We find the wild animals in some countries to be coloured and marked so like their surroundings that they cannot be detected while at rest. In South America there are two classes of wild cats quite differently coloured, but each harmonising with its environment. The jaguar which steals along the river banks in a dull speckly light is coloured accordingly. On the other hand, the puma which moves about among the reddish grass tops has a coat to harmonise with the grass. This protective colouring is not the sole possession of cats; it is common to lizards, snakes, frogs, beetles, butterflies, and others.
One may often see in Natural History museums specimens of leaf-butterflies, and it will be observed that, while at rest, the underside of the butterfly's wings are scarcely distinguishable from the leaf of the bush. We have a most interesting collection of such insects and animals at the Natural History Museum in London.
One of the most interesting phases of this mimicry is that of some tropical butterflies, which, through long ages of evolution, have succeeded in protecting themselves against their enemies by imitating the colouring of a poisonous butterfly which their enemies will not eat. Very gradually would these protective colourings be evolved. At first the resemblance may not have been very great, but those having some similarity to the inedible butterfly would escape destruction, and through a long inheritance the resemblance would be increased until the present final stage was reached. Another case is that of a beetle which has evolved a colouring which is a perfect imitation of a wasp. Those individuals which were the poorest imitations would, of course, be cut off by their enemies. And so we see that "adaptation to environment" and "heredity" have played an important part in "Natural Selection."
Although the zoologist cannot trace out a definite pedigree for man, he sees many proofs of the fact that man has been evolved from the very simplest organisms. The embryologist has much of value to add by way of corroborative evidence, but it will not be convenient to touch upon that side of the subject in a volume such as the present, except to give a few very simple illustrations.
We know how the butterfly is evolved from the caterpillar's chrysalis. We know how the frog is evolved from the fish-like tadpole. The tadpole is really a fish; has lungs and gills, and its general structure is just like the lung-fish of Australia. In Chapter VI we found that the palaeontologist declares that all frog-like or amphibious creatures were evolved from fish, and we now see that the frog in its embryonic state goes through similar phases.
Again, if we examine the embryo chicken within the egg we find that it commences with a small and simple jelly-like organism. Then at a certain stage we find on the sides of its neck a series of gill clefts like those of a fish, while the blood-vessels are arranged not as they are in the fully developed bird, but in the same way as they are in a fish. Further, the embryo chick shows no signs of wings or feet, but merely a simple paddle-like structure. Indeed, if this, embryo chick were found living free in nature it would be in reality a fish.
Probably many of us have seen the slow and imperceptible growth of a flowering plant reproduced by the cinematograph in a few minutes. The embryo chick, in the short time required for its development, reproduces over again the long life-history of its evolution in ages past. This truth was set forth by the great German naturalist Haeckel, in the following words: "The individual in its development recapitulates the history of the race."
When speaking of the extinct creatures of long ago, one is sometimes asked how it was that these animals became extinct. It might be thought sufficient to point out that the law of "the survival of the fittest" applies to the race as well as to the individual. Also that a change of environment and climate might annihilate a species. It is true also that one species of animal becoming superior to another would prey upon it, the climax being the superiority of man, and his conquest of all other living creatures. But all these reasons are not sufficient; the question of extinction is a very complex one.
At the meeting of the British Association, in 1912, the following resolution was passed deploring the rapid destruction of animals and flowers throughout the world. The resolution was adopted in the following terms: "That the British Association for the Advancement of Science deplores the destruction of fauna and flora throughout the world, and regards it as an urgent duty that steps should be taken, by the formation of suitably placed reserves, or otherwise, to secure the preservation of examples of all species of animals and plants, irrespective of their economic or sporting value, except in cases where it has been clearly proved that the preservation of particular organisms, even in restricted numbers and places, is a menace to human welfare."
In a preceding chapter we had occasion to consider the industrial methods of the primitive natives of Tasmania. How, then, did that primitive race of mankind become extinct within quite recent times, and within the short space of fifty years after the advent of the Europeans on the island? This Van Diemen's Land, as it was christened by the Dutch discoverer nearly three hundred years ago, was left in peace for a very long time. There are no visits recorded during the following century, but it was explored by French and English navigators about the beginning of the nineteenth century. Shortly after this a few soldiers and convicts were sent from Sydney to form a settlement. Then many settlers arrived and were granted land to cultivate, being provided also with convicts to work for them.
At that time there would be about three thousand primitive natives living on the island. These formed several distinct tribes occupying different parts of the island, and each tribe was quite foreign to the other, having different dialects and different customs. We have seen how very primitive were their stone implements. Their dress, when any was worn, was as primitive, and so was their food. Indeed, at certain seasons they occupied the shores and subsisted entirely on shell-fish.
It is often stated that the presence of the settlers caused the natives of Tasmania to go inland, and that the foreign tribes, coming into conflict with one another, commenced a warfare which ultimately extinguished the whole population. But the white man's actions were not entirely passive. Unfortunately some of the settlers shot down the natives without mercy, the primitive creatures having only spears and clubs with which to defend themselves. After some years the total native population was reduced to a few hundreds. One settler had compassion upon the poor helpless natives, and he succeeded in getting the remnant of the different tribes transferred to a neighbouring island, but the population decreased gradually. In less than twenty years there were not fifty natives left, and fifteen years later there were only six survivors, and finally the last of these passed away.
Occasionally one sees a band of Esquimaux at one or other of our great International Exhibitions. There is something pathetic about such a sight, for these primitive people were at one time a great race, but are now disappearing; indeed, there are not many thousands left. The white man is not directly responsible in this case; it is the Red Indian who does the massacring, but the presence of the white man has introduced diseases which have increased the death-rate to a great extent. And so we see how it is possible for extinction to occur even among intelligent human beings.
As already indicated, we should keep in mind that the question of extinction is not a simple one. The only way in which we can account for the extinction of some animals is that they had become so specialised to suit particular conditions, and that a change in these conditions would render them helpless. Not only were there great changes of climate from tropical to arctic, but the very level of the land kept changing. We have traced some of the factors which lead to extinction, but there is much still to be discovered.
Anthropologists have traced out a possible pedigree for man right back to the very simplest forms of life, but particular interest attaches to the last stage in which man was evolved from the ape. What determined this great evolution? Was it because the primate acquired an erect attitude, leaving its hands free, or was it the acquisition of speech, or did the development of the brain precede these? Eminent men have championed, each of these factors as being the primary one. The most recent address upon this subject at the British Association meetings was that of Professor G. Elliot Smith, who maintains that the development of the brain came first. This enabled the primate to make skilled movements of the hands, and then followed the erect attitude, which in turn stimulated the further advance of the brain.
But what caused man to differ so very much from his living "forty-second cousins," the gorilla and the chimpanzee? In the address referred to, the learned anthropologist, with his intimate knowledge of natural science, draws this interesting picture: "Long ages ago the ancestors common to man, the gorilla, and the chimpanzee became separated into groups, and the different conditions to which they became exposed after they parted company were in the main responsible for the contrasts in their fate. In one group the distinctively primate process of growth and specialisation of the brain, which had been going on in their ancestors for many thousands, even millions, of years, reached a stage when the more venturesome members of the group, stimulated perhaps by some local failure of the customary food, or maybe led forth by a curiosity bred of their growing realisation of the possibilities of the unknown world beyond the trees which hitherto had been their home, were impelled to issue forth from their forests, and seek new sources of food and new surroundings on hill and plain, wherever they could obtain the sustenance they needed. The other groups, perhaps because they happened to be more favourably situated or attuned to their surroundings, living in a land of plenty which encouraged indolence in habit and stagnation of effort and growth, were free from this glorious unrest, and remained apes, continuing to lead very much the same kind of life (as gorillas and chimpanzees) as their ancestors had been living since early times. That both of these unenterprising relatives of man happen to live in the forests of tropical Africa has always seemed to me [Professor Elliot Smith] to be a strong argument in favour of Darwin's view that Africa was the original home of the first creatures definitely committed to the human career; for while man was evolved amidst the strife with adverse conditions, the ancestors of the gorilla and chimpanzee gave up the struggle for mental supremacy simply because they were satisfied with their circumstances; and it is more likely than not that they did not change their habitat."
Very gradually there was a further development of the brain, filling out the frontal part which gives man his distinctively human forehead. Then from making simple cries and grimaces, such as all social groups of animals employ when desiring to communicate with their fellows, there was evolved very gradually an intelligent speech. The least imaginative among us can realise what an immense impetus would be given to further evolution by the ability to pass on a statement of experiences from individual to individual. If we think of our early school life, it is clear how the beginnings of our own personal knowledge were dependent entirely upon speech; gradually we have acquired the common stock of beliefs. If we once realise the vast importance of speech, we cease to marvel at the very long period during which primitive man continued to use simple stone implements and roughly chipped flints.
Having once acquired an intelligent speech he then made great strides.
We have seen in the preceding chapter that there has been practically no evolution in man himself since he became a civilised being. A careful study of the most ancient mummies has failed to show any signs of present evolution in a period of six thousand years. But there are very marked signs of evolution in man's industries. The primitive distaff and spindle has evolved into the simple spinning-wheel, and that again into the modern spinning machinery. In all branches of industry we can trace a true evolution, but this is beyond our present province, and the present author has already dealt with this subject in his Romance of Modern Manufacture.
With the crowding together of civilised man into cities, with their confining influences, it is more difficult to keep the machinery of the human body in good working order. People get "run down in health," and the doctor orders them away to the open country for a holiday. It will be of interest to consider what discoveries have been made concerning our own bodies.