THE FUTURE OF MANKIND

Hokitika Guardian, 27 June 1931, Page 6

THE FUTURE OF MANKIND

TIME’S ENORMOUS BACKGROUND TRUSTEESHIP OF EVOLUTION. UNKNOWN HEIGHTS AHEAD. In the course of an article in the “New York Times,” discussing evolution and where Darwin’s theory stands to-day, Professor Julian Huxley, the well-known English biologist, and himself tlie grandson of Thomas Henry Huxley, who was Darwin’s foremost champion, remarks: — “One very interesting developmentsince Darwin’s day - concerns the length of time during which life’s evolution has taken place. In the last centum physicists like Lord Kelvin allowed only about 40,000,000 years for the whole life of the earth; and this was universally felt by biologists not to give nearly enough elbow room foi evolution. With the discovery of radium, however, tlie whole question changed, and it was at once seen that the cooling down of the 'earth would lie much slower than was previously thought, the length of time available for evolution much greater. To-day the radio-active minerals have actually given us a means of determining within fairly nar’row limits the absolute age of different rocks in the earth’s crusts. The method is based on the fact that radio-active elements are always changing into other, inert elements, and tlint the change goes on always at the same rate whatever the outer conditions. The proportions of radio-active elements and inert endproducts found in crystals of radio'active minerals can thus be utilised as a sort of cosmic clock to tell us the date at which the crystals were first formed

When Water First Condensed. Utilising these results, we now can say with some assurance that the time which has elapsed since water could first condense on this planet, and sedimentary rocks bo laid down, is somewhere in the neighbourhood of 1,500,000,000 years. Life probably appeared not long (geologically speaking) after this, and certainly before 1,000,000,000 years ago. Owing, however, to the great pressures and temperatures to (Vliieh these early rocks have been subjected, most of the fossils in them have been squashed or baked out of recognition. The earliest rocks in ‘ which well-preserved and abundant fossils ex- 1 ist were laid down about 500,(XX),000 years hack ; and by this time the iru'j-, ority of the main gboups of animals had already appeared—worms, crablike creatures, jelly fish, sponges, and so forth. Back-boned animals, on the other hand, are first known about 100,000,000 years later, and it is not until about 300,000,000 years ago that tlie land became colonised by life—first by plants and then very soon afterwards by animals. The first back-lmned land animals were amphibians like large salamanders; it was not until about 250,000.000 years ago that the earliest reptiles were evolved, and it was another 100-.-000,000 years before the earliest mammals and birds bad become well established. All these early mammals and birds, however 'were very different from those we know to-day; birds and mammals of modern type date back to between 50,000,000 and 100,000,000 years ago, and the same seems to be true for flowering plants and the higher types of insects.

Youth of Modern Man. Against this time-scale, how insignificant appears the period during which man lifts been on earth! The earliest remains of human skeletons or human workmanship date back between 500,000 and 1,000,000 years; and there is no question that man’s divergence from his simian ancestors cannot, at the outside, have taken place more than

five or ten million years ago. AIL early men belonged to types which are now extinct and were , more apelike than ourselves. Our existing species, modern man, is exceedingly youthful, biologically speaking, for all the remains le‘t by him fall within tlie. last 100,000 years.

|t is against this enormous background of time (as opposed to the few thousand years to which our ancestors had grown accustomed from the Bible cosmogony) that man must think of the problems of his present and his future, ft is worth remembering that the " physicists and astronomers hold out tc us the prospect of similar enormous stretches of time for the future of our race. Before the earth cools down so much as to make life impossible, it seems that we can expect at least 1,000,000.000 years and probably more—about the same length of time which was occupied in the evolution of our own species from the original primitive microscopic, undifferentiated, blobs of living matter.

What Evolution May Produce, The final reflection which facts suggest is this: There is no reason for supposing that man as he at present exists is nearly tlie highest type which call be produced by evolution, any more than there was for thinking that the early cavemen were the highest type, or the early mammals, or the giant reptiles which dominated the world 100,000,000 years ago; and by means of increased knowledge nian should he able to set himself deliberately to improving his own race. Furthermore, li ehas abundance of time in which to carry out his projects. He is the one organism who has become endowed with conscious reason. By means of thi s he can, as it were, get outside of himself: and see himself in relation to the rest of the world and to the destiny of this planet; by means of it lie can, is he so wishes, become the trustee of evolution, and continue to new goals the age-long process which has given him birth.