THE NEW EVOLUTION

Dominion, Volume 1, Issue 91, 10 January 1908, Page 8

THE NEW EVOLUTION

WHAT IT REALLY MEANS.

I INVESTIGATIONS IN. NEW \ ZEALAND,

(Specially Written forTheDominion.), (By Dr. L. Cockayne.) From time to time there appear in the papers, usually in connection with tho Californian plant-breeder, .Burbank, who is, designated the wizard of horticulture, marvellous accounts of. tho creation, as it is called, ■ of plants ■so 'strikingly different 'from- their fellows that a miracle appears to havo been' wrought. Such stories have all tho appearance of authenticity , and are firmly behoved in by the general public,, so thai a falso conception of man's power with regard to producing new forms of plants and animals lias become established. : .Were it indeed': ■true that the breeder could accomplish onetenth part of what'is claimed, then would -man be in. verity the monarch of; tho universe since he would need only to construct food plants full-, of nutriment, which would thrive moreover in the-most , barren spots and beVlikewise immune to all dis--1 eise. Not that an approximation'to tho above is not possible' in theory, but; in fact it is miles distant at'the present time. Burtank has - done ■no more ■ than .the ptantbreeders of 'Europe, neither are'his methods other in principle -to theirs, nor . indeed so enlightened aa those which now result, from a much more accurate scientific, knowledge. •

fTho Work ot De Vries. Plant-breeding depends upon two principles namely, the tendency of, all speciets to vaTy and tho crossing l of allied forms possessing different characters. With the latter Ido not deal here,', the former is alone my topic, it -is only within the last year or two that a true cbrioeption of variation' 1 has arisen. This forward step is,the work of tho celebrated botanist of' Amsterdam, Professor Hugo de [Vries, and .is the outcome of many years most painstaking experiments, guided by his trained and master mind. Every cultivator of plants or breeder of. animals knows well •that no two individuals of a- species • , aro exactly alike.- The flower gardener cannot ■match any . two blooms in his bed of panaes, nor -has the poultry- fancier .any exact duplicates amongst .his, Wyandottes. •Variations such as tho above are, called by 'De VrieSj fluctuating., Now, according to the illustrious Darwin, individuals possessing some advantageous-character, although very slight, would be more likely to survive in that struggle for existence to which,all,organisms are - subjected than those destitute of such benefit, while the beneficial character Tfould bo handed down to . the progeny and would generation by generation become more and more intense . until . finally an absolutely new species would bo evolved, and the now .'extremely intensified original fluctuating character, he hereditary. This theory ■was founded on a vast mass of data col?: lected from the breeders of Darwin's; day, and both from its intrinsic probability,' the great prestige of its author ; and the . strenuous advocacy of his gif ted - lieutenants, Huxley especially, it has received general acceptance and is still the leading theory.-of; • evolution. De Vries, however, has examined the evidence, of the breeders afresh, adding much thai was necessarily unknown ,to Darwin, but above all he has conducted ; plantbreeding,, experiments himself;',' a 6tep apparently most essential, but 'one previously neglected by-other evolutionists, " who have contented themselves for the most part with a constant flow' of words merely; adding little or nothingjor about half a century to Darwin's - famous doctrine. ,In short, through De Vries the study 'of evolution has become experimental, that is truly scientific,a great advance "-indeed. 'De Vries has moreover shown that besides' fluctuating' variability, there is second \ and more important kind of variation so far as evolution is concerned, when a new character makes its appearance in the offspring quite different from , any to be found in the parents; and that such a character, and this is a crucial point, may be hereditary. Thus a .new character may appear not as the result of a tedious selection by .Nature,' extending through a vast period-of'time,.'but.as a sudden jump. Then natural selection can come, into play, and if the iiqw. character is beneficial it will he preserved, hut 'not intensified,; and the new species will increase in numbers at the expense of its more fioorly,equipped competitors. . Such a.,new. species.' which has originated, all.,at once, is called by Da. Vries a mutant and .his. theory the mutation' theory in opposition 'to Darwin's natural selection. '- , ; :

Economic Importance of the Mutation Theory. Two matters concern lis specially in New

Zealand. How docs our flora support, such a view as tho above, and what is mo practical value to us as a farming community.'' Tho latter question 1 .will ..attempt to answer first, and tins will also reply in part to tho first query. According co Do vries, Darwin's conception that the small fluctuating .variations can bo intensified to beyond their normal capacity for variation aiid' become hereditary is a fallacy. \ He, Bateson of Cambridge, a most.important.worker iu the, same field, and their, followers deny, and ' their assertions are i based on experiment, that a show pansy for instance can be made from the small wild field pansy of Europe, by selection alone, or that in the sauio manner a polish fowl with its topnot' of feathers can be bred from ; the ordinary barn-door species, and so on with other artificial races or plants and animals. They say that in all such eases tho breeder has found a sport as he calls it ready-made, that is an in T dividual (mutant) has suddenly appeared, how no one can tell, with a new arid hereditary character. Such an individual is isolated and by selection the character may be increased lip to its fluctuating limit. ITurbank's stoneless plum and spineless cactus appeared ready-made by Nature, the celebrate-] plant-breeder did not create them. What he did'was to. have the wit, to see they were novelties, and to appreciate- their capabilities for tho artificial evolution; of new economic races. - ; Potential Wealth in New Zealand Plants.' My own studios of tho New Zealand flora have convinced me that many of our so-called species are not distinct entities, but are a collection of definite races with distinct.and hereditary characters. This I have demonstrated . for certain of our speedwells and willowherbs and have experimentally isolated various hereditary forms. At tho present timo, with the spread .of settlement, there is a crying need for a grass suitable, for making fertile the, barron gum fields. Such a desideratum has been found to somo extent in tho species Danthonia pilosa and Danthonia semiannularis. .. But these spccies are eminently variable, though as yet the variations have not been studied scientifically, i.e., experimentally. Bearing in mind however, what has gono beforo, it is almost certain that tho species in question aro mado up of many races which aro fixed and hereditary, all of -which must havo, different properties, slight it may bo, but some one or other of which will be superior to the others as a grass for dry or barren spots. This desirable species of the future is thus doubtless already made by Nature, and exists somewhere or other in tho Dominion, but it remains for tho plant-breeder to isolato it from tho mixture of different entities now known collectively as Danthonia and to breed it puro. Here no long selection-period would bo required, but ono choice alone, one separation i of. tho species into its components or mutants, and then tho testing each regarding the economic characters desired. This dono, hybridisation could be brought into play and by tho application of scientific breeding oil.tho lines of Mendel a still more important fodder plant bo tho outcome. But it must not bo forgotten that such experiments must bo conducted with oxtromo caro and require the supervision of scientific men acquainted with modern methods and filled with tho 'spirit of resoarch'. Nor is it tho waste lands alone which need special fodder plants. Tho mountain pastures aro a source of constant wealth, and their improvement has hardly been attemoted, vet there too are probably incipient

species, waiting to play ; their part in man's service. Thus it" is quite conceivable that seeds remain ungarnercd in tho Dominion worth many hundreds, .nay thousands 1 of pounds, since they represent vaster flocks and, barren lands ~, made,, . fertilo! This may sound sensational,, but sp. would havo been the announcement of tho ;,Rontgcn Rays or wireless . telegraphy before their advent. Sonsationalism is but a;,phase of the unexpected, which is just what science most expects. Many other Now Zoaland plants suggest an examination for their mutants on economic grounds, and none more so than Phormium tenax. . ' An Epoch-making Discovery. Growing in a field in Holland, Do Vries noted certain-forms of. an evening primrose, which differed from any iknown to.science, sido.by sido with Larmarck's giant species. By a series of brilliant experiments, ho proved; boyond :a - doubt, that these had 'originated-at ono jump from the last named, which ho thus* found to bo in a state of mutation, that is it ,Was actually in the act of producing species- new-to the world. This truly , epoch-making.- discovery upon which the hew evolution doctrine is based has led botanists in various regions to examine their floras for similar, phenomena, and accordingly a number of moro =or . less authontic imitations'havo been already recorded. Mutations in the New Zealand Flora. New Zealand, through■ its isolation during long ages,- 1 and through, the diverse origin of its flora,, offers .special' advantages for testing the' theory, of De' Vries. . The. extreme variability of many plants would lead olio to suspect.mutations even now, while the iioit. of introduced ~ species growing under : conditions more, or • less different from those of their natural habitats, afford studies in unpremeditated experimental ovolution on a gigantic, .scale. ' Uhforunately the workers. in this; fascinating' field are almost nil, but'a's its; economic ;capabilities are recognised.'they should increaae in numbers. But already a.'few examples ( have come to my notice ( of, what may . be truo mutants ,of quito.'recent, origin; The great Chatham Island fprget-merjiotJ . normally bluo, has given rise, to, a. white variety, which, though fairly common, in,gardens, originated from one plant discovered by > Mrs. Chudleigh near Wharekauri, who although a most keen observer for many years, has seen but tho one wild, plant. ■ Other,, examples of possiblo mutants, but of, which'tho space at my .disposal forbids details aro: Tho white clianthus,' > . the red and crimson manukas, tho and variegated, flaxes, the whito southern rata, Chewing's fescue, tho bronzy and variegated cabbage trees, tho flax with-a:'leafy inflorescence.. With regard to the introduced plant's, all I can say hero is that some remarkable forms havo arisen in the broom, Californian tree-lupin and the both' distinct changes in ,colour of flower, in" time-of blooming arid in shapo of blooms, and this is the more remarkablo as tho two first-named plants vary -hut slightly in thorr uativo land. The above shows what a.rich field for resoarch tho new evolution on experimental lines offers in New Zealand, and one which tho public at large should , surely appreciate, seeing its importarit economic : bearing.