EVOLUTION

Southland Times, Issue 20525, 29 June 1928, Page 5

EVOLUTION

TRANSFORMATION OF SPECIES. THE PORTO SANTO RABBIT. To the Editor. Sir, —I apologize for reopening the subject of evolution after so long a lapse of time but do so because my attention has been called to two letters in the Southland Times for Dec. 24 last which, if allowed to pass without comment, may leave an impression that they are unanswerable. Messrs “X” and Frank Sampson appear to be attempting to discredit, the former by appeal to religious prejudice the latter to an ad Captandum Vulgus ridicule, the statement of a previous correspondent, “P,” that species undergo transformation. The animal instanced by “P” as having recently undergone change of species is the Porto Santo rabbit, and as the two writers have poured out the vials of their wrath over P’s illustration a few facts may be brought forward that will enable your readers to judge whether his observations were true or false. It will be well here to state that the word “species” implies a group of animals or plants the individuals of which closely resemble each other both superficially and in anatomical detail, breed together and produce fertile offspring which in their turn are capable of reproducing their kind; it is the fluctuating variations, large and small, which affect all offspring, that form the basis of species-making. In his lectures on Biology at the Humboldt Academy, Berlin, Dr. Curt Thesing says:— If some individuals of a species are separated from the rest and placed among new conditions this fact may give rise to new species. An interesting instance is supplied by the rabbits which were liberated in the beginning of the 16th century by Portuguese sailors on a small island near Maderia, Porto Santo. They have assumed a number of quite distinct characteristics; they have grown much smaller, are distinctly “vicious,” have a reddish fur, and are indeed so widely differentiated from their European parents that it is impossible to pair them.” Prof. Guenther of the University of Freiberg, Baden, writes in his Darwinism and the Problems of Life:— “W e now know that species are changeable, and have actually changed; that one species may be formed from another. We knew of several cases in which species have been so much modified within the historical period that they can no longer be crossed with their earlier relatives. In the year 1419 rabbits were introduced on the isle of Porto Santo. The descendants have become very unlike their ancestors, and differ from them in their peculiar colour, rat-like shape, small size, noctural habits, and extraordinary savageness. But the most, remarkable point is that they can no longer be crossed with the European rabbit and have, therefore, formed a new species in this comparatively brief space of time.” Sir Alfred Russel Wallace in his two works, World of Life and Darwinism says:--“A few cases have been recorded in which Nature has been caught, as it were, at work in the actual formation of new species at the present time. A female rabbit having had a litter of young on board, they were all turned loose on this small uninhabited island. This was about 1419, and from these alone the island became fully stocked. They were very much smaller than English wild rabbits, being little more than half the weight, and nearly three inches less in length. We have here a very remarkable series of difference in size, colour, and even in the form of the skull. The rabbits are all the produce of a single female; they have lived on the same small island for 470 years, and they still abound there.”

In his Variation of Animals and Plants Darwin gives a detailed account of these rabbits from their origin in a doe that belonged to Mr Gonzales Zarco who, at the time, was sailing to Madeira. Between 1861 and 1865 Darwin made a careful study of the creatures both from the dissection of five dead specimens and observations of four living ones, two at his own home and two in the Zoological Gardens. The following is condensed from his account:— After the liberation of the mother and young on the island they increased so rapidly that they became a nuisance, and aclually caused the abandonment of the settlement. Thirty seven years subsequently, Cada Mosto describes them as innumerable; nor is this surprising, as the island was not inhabited by, any beast of prey or by any terrestrial mammal. In the Zoological gardens the two little Porto Santo rabbits were extraordinarily wild and active, so that many persons exclaimed on seeing them that they were more like large rats than rabbits. They were nocturnal to an unusual degree—their wildness was never in the least subdued —a singular fact considering that they are descended from a domesticated breed—Mr. Bartlett (the Superintendent at the Zoo) could never succeed in getting these two rabbits (both were males' to associate or breed with the females of several breeds which were repeatedly placed with them. We see that these animals do not, under new conditions of life, revert to or retain their aboriginal character, as is so generally asserted to be the case. Now it will be noted that visitors to the Zoo, as well as Darwin and Guenther, described the rabbits as “rat-like.” Your correspondent "X.” presumably with the motive of conveying the impression that “P” had said something absurd and untrue, writes:— “He (i. e. ‘P’j makes an assertion (as fact I that in its essence simply means that rabbits have brought forth rats.” Mr Sampson asks a number of questions concerning this rabbit, few of them to the point are answered in the above excerpts. The others, like the conundrums such as “Can evolution explain why a red cow that eats green grass gives white milk?” perpetrated by the late W. Jennings Bryan in his anti-evolutionary campaign, are mere ‘dust-throwing.’ The relative constancy of some, and relative instability and mutability of other species are familiar phenomena in biology. Certain shrimp-like animals exist to-day that differ scarcely at all from their farback Cambrian ancestors; ants found imprisoned in amber known to be at least 2,000,000 years old have been identified with living species. Even that insurgent prodigy of nature, Homo Sapiens, is by n.o means the latest species to appear on earth, the clothes-louse and most of the microorganisms causing the specific diseases of humanity are far more recent advents. By changing the environment bacteriologists have been able to convert harmless mineral feeding microbes into aggressive diseasegerms feeding on the tissues and, conversely, the latter have been involuted into the former. By gradually altering the salinity of the water Schmankewitsch after many generations succeeded in changing one kind of brine-shrimp (Artemia Salina) into another (A. Muklenhausii) and vice versa. By exposing the germ cells of a certain alga (Oscillatoria) to a green light it is possible permanently to alter the colour of the alga to red. Among plants de Vries produced from the large tall Evening Prim-, rose (Oenothera Lamarckiana) the short broad O. Lata and the tiny leafed O. Nanella, both of which are well entitled to rank as new species. Mr Tate Regan, Keeper of Zoology in the British Museum, has shown that among fishes the first step in the origin of a new species is not a bodily change but the adoption of new habits forced on by the organism by a new and restricted environment. Other zoologists working independently with amphibia, reptiles, birds and mammals as their material have found similar causes to be operative in species-formation. The censensus of opinion among authorities is that animals and plants have been under-

going transformation of species for many hundred million years and that the process is still going on; sometimes this is so slow as to savour of stagnation, in other cases so rapid that we can witness the change. The further back we trace the genealogical tree of life towards the common ancestral stem the fewer do we find the total number of species. In the Cambrian age, for example, fossils of some 700 species have been found, but in \the succeeding Silurian age these had already branched out into 10,000 species. When Linnaeus, in the middle of the 18th century, classified 4000 species of animals alone in his System of Nature, he created a panic among the orthodox concerning the responsibility of Noah in having had to accommodate twice this number in the ark. Thirty years ago the known species of living beings exceeded 90,000 and to-day they run into hundreds of thousands. Sixty species of hares and rabbits alone exist, and as “X” and Mr Sampson have displayed so warm an interest in Lepus Huxleyi, as the Porto Santo species has been termed in contradisdinction to the common L. Caniculus, they may care to hear about a still more remarkable species, Romerolagus, recently discovered on Pcpocatapetl in Mexico. Though called a rabbit it presents also features of the hare, it has no visible tail, its skull is very rabbit-like but unlike that animal only six ribs articulate with the breast-bone instead of the normal seven. A telling example of the evolution of new species within historic times is that of the golden carp, Carassius Auratus. From the evidence of a passage in the Chinese classics it would appear that about 1200 A.D. the chance appearance of a gold colour in the wild carp that inhabits the rivers of China led to its selective breeding. During this process which culminated in the attainment of the desired golden colour, certain extraordinary structural variations began also to appear and to these the attention of the breeder was next turned with the result that a number of bizarre types of fish have, as it were, been called into being. One of these is the Egg-fish with its tailless and globular body; others are the Buffalo-fish, with curious protuberance over its head, and the Celestial-fish with telescope-like eyes. In the Comet-fish and the veil-fish some fins have been actually doubled while others have been so enormously lengthened and thinned out that they trail behind the creature like a comet’s tail or droop around it like a wedding-veil. After but four generations nearly all the offspring repeat the structural abnormalities of their parents and thereafter breed true, only a small percentage reverting to type. What is the explanation of these newly created forms? Loeb and others have shown that addition of certain chemicals to sea-water containing fish-spawn resulted in the production of Cyclopean fish possessing a single central eye in lieu of the normal two, a result ob-. viously caused by direct action of the chemicals on the germ-cells. The Chinese were in the habit of keeping their fish and spawn in small earthenware jars stored in dark ill-ventilated rooms, and it is probable that the ensuing “mutations” resulted from the absence of the normal stimuli to development and the incidence of abnormal stimuli consequent upon increase of carbon dioxide, deficient oxygen, light, etc. It is difficult to understand what “X” exactly means in his assertion that “Mendelism utterly disproves the suggestion of environment and short gestation,” but if it be that certain ratios of characteristics inherited by the offspring disprove the effect of environment upon their ancestors, then his assertion contradicts some of the fundamental phenomena of life. It is true that the effects of environment upon the body cells are not, in the opinion of the overwhelming majority of biologists, transmitted to offspring, only is environmental action transmitted when it has affected the germ cells, but such facts are neither proved nor disproved by Mendelism. No one has done more in the practical evolution of new fruits and flowers than Luther Burbank who worked largely on Mendelian lines and with a true Lamarckian faith in the mouldding power of the environment. “All wild plants of any species,” writes this wizard of evolution whose magic wand has called forth so many marvelous growths from the womb of Mother Earth, “are under almost identical environments, having their energies taxed to the utmost in the fierce struggle for existence. Any great variation under such circumstances is not likely to occur, and is much more likely to be stamped out at once by its strugglig competitors unless the variation should be of special use in competition in which case it will survive and all others may be supplanted by it. Thus we see how new species are often produced by nature, but this is not her only mode. Crosses and hybrids arc very often found growing wild where two somewhat similar species grow contiguous, and if the combination happens to be a useful one—the new creation is encouraged by nature; then time and environment fix it, and man comes on the scene, perhaps ages later, and discovers it, and, —wonders where the connecting links have gone. It is botanically classified as a new species which it is most certainly.”

Mr Sampson quotes the following from Sir Arthur Keith’s Presidential Address to the British Association for 1927 as published under the title Man’s Origin:— “The audience which I now have the honour of addressing, and that larger congregation which the wonders of wireless bring within the reach of my voice, if not convinced Darwinists, are yet prepared to believe—when full proofs are forthcoming—that man began his career as a humble primate animal, and has reached his present estate by the action and reaction of biological forces which have been and are ever at work within his body and brain.”

To this Mr Sampson then adds his own italicised comments, “No proofs are yet forthcoming.” The words of Prof. Keith have been torn from a context the original sense of which would have furnished the reader with an opposite opinion to that imparted by Mr Sampson’s version. The point stressed by Sir Arthur, which stands out pre-eminently clear in its full context, was that when Sir Richard Owen addressed a similar meeting in the same city 69 years previously his audience was convinced, almost without a dissentient, that man had appeared on earth by a special act of creation, whereas Sir Arthur’s audience, if not convinced Darwinists, were prepared to believe in evolution if given the proofs. Further, Mr Sampson without acknowledging the fact has placed a part of Sir Arthur Keith’s sentence into italics and parenthesis, and after thus misquoting and misrepresenting what had been said he sums up with the statement “no proofs are yet forthcoming,” concealing from his readers what he must have known, viz., that Sir Arthur adduced the proofs, both in his address and on page 12 of Man’s Origin, as a special paragraph headed “Proofs of our Anthropoid Ancestry.” Mr Sampson’s special pleading against evolution amounts, therefore, to a Suppressio Veri Suggestio Falsi. The theory of evolution is thousands of years old; before the dawn of our era it was taught by Heracleitus, Epicurus and other ancient Greeks and its praises sung by the Roman poet Lucretius. Darwin brought forward a certain hypothesis of the manner in which evolution operated among animals and plants termed Natural Selection with consequent survival of the fittest and natural rejection with elimination of the unfittest. He freely admitted the possibility of there being other subsidiary or even alternative methods of evolution, but up to the present the Darwinian theory, with slight modifications, has held the field. The moment, however, a better working hypothesis is forthcoming, it will be at once adopted by biologists. In every department of knowledge—physics, chemistry, astronomy, biology, language, society, ethics and even religion—evolution is unhesitatingly accepted by men of scientific repute in every country of the earth. “It cannot be too strongly emphasised,” says Professor Elliot Smith, F.R.S., of the University of London, ‘‘that to modern scholars the reality of evolution is as certain as the fact of the earth’s revolution around the sun.”

Can and Sampson bring forward any other explanation than that afforded by the evolution of the following facts:—(l) The blood of man is chemically related to that of all other animals, but the relationship to that of the eel, frog and snake is less than it is to that of the monkey, and in the case of the anthropoid ape the relationship is so close that the two bloods are scarcely distinguishable. Professor Nuttall, of Cambridge, has shown that if the blood (after certain preliminary treatment identical for each case) of one species be added to that of a similar species a voluminous precipitate results; in the case of dissimilar species a scanty, and in very widely separated species no precipitate occurs. Thus, when to man’s blood was added that of a lowly mammal such as a marsupial there was an absence of precipitate, mixed with the blood of the horse, 2 per cent, of precipitate fell down, with that of the bear 8 per cent with that of a baboon, 29 per cent, of that of the Orang Utan 42 per cent of the Gorilla, 64 per cent., and with that of another human being, 100 per cent. The blood corpuscles ot a frog are very rapidly destroyed by the blood of man, those of a monkey are but slowly destroyed, while those of a higher ape only disappear after an interval of time approximating to that resulting when the blood of two human beings is mingled as in the operation of transfusion. (2) The lowest animals with teeth have the power of renewing these indefinitely when worn out, a power lost in the higher mammals. Whalebone whales never possess permanent teeth, yet their young before birth have two distinct sets which follow one another and then vanish. Fossil birds are toothed, and many of the embryos of modern birds have teeth in their beaks as well as claws on their front limbs. Man has normally but two sets of teeth, occasionally, however, he has three and, yet more rarely, four. (3) The porpoise before birth shows external vestiges of hind legs, after birth it has only the paddle-like fore-legs. The whale and the python have the skeleton of hind legs buried as useless encumbrances in the depth of their tissues. (4) The Orang Utan and Man possess normally 12 pairs of ribs. Occasionally, however, they show 13 pairs throughout life. In the embryos of both, 13 pairs of ribs is the normal state.

(5) Man and the four higher apes possess no visible tail after birth though their embryos possess a well-marked one. Occasionally a human being is born in whom not only does the tail persist, but also the little muscle known as the Agitator Caudae that wags it. (6) Not a single structure is found in the brain of man that is not present in the brain of the higher ape. As Professor Elliot Smith says:—“The human brain possesses no formation of any sort that is not present in the brain of the gorilla or chimpanzee.” The differences are purely quantitative.

When Sir Charles Lyell in 1883 was shown evidence of man’s existence in the valley of the Meuse in company with animals known to have been extinct for many thousands of years he was so cautious, so anxious to explore every possible avenue that might admit of error, that, he would not permit himself to admit the fact in print for 30 years. Darwin conceived his idea of the origin of species in 1837, but not satisfied with what many would have regarded as an overwhelming array of corroborative facts, it was not until 1859, and then only through the persuasion of other biologists, that he published his theory. Luther Burbank spent most of a lifetime observing, testing and sorting fruits and flowers. On one single tree he had 600 plum-grafts. “Out of 200,000 seedlings,” he writes, “I found one showing a faintest trace of sky-blue and planted the seed from it and got next year one pretty blue one out of many thousand and now I have one almost pure blue.”

If the carefully weighed and checked opinions, based as they are upon a long and laborious expert life-work, of scientific men such as these, be contrasted with the hasty and ill digested denunciations of the opponents of evolution who rush blindly into the arena of biology with minds deliberately foreclosed to the inception of new ideas and quite “untrammeled with any least acquaintance with their subject,” the significance—to say nothing of the humour—of the situation stands out in all its clarity.—l am, etc.,

CHARLES M. BEADNELL. Aberystwyth, Cardiganshire, Wales, April 26, 1928.