Page sixteen 



EVOLUTION 



June, 1931 



The Amateur Scientist 



A Monthly Feature 



WHAT SHARP EYES SEE 



By PAULINE H. DEDERER 



ing a shining path of slime. On these 

 small fry the birds feed, and so we find 

 a chain of nature or a web of life as 

 Darwin called it, which forms the fabric 

 of the community life. 



Good examples of fresh water associa- 

 tions of animals may be found among 

 the inhabitants of swamps, bogs and 

 pools. Take a pool or small pond in a 

 meadow. Here is a miniature world in 

 the universe of the countryside — and 

 how may the inhabitants of its depths 

 speculate upon the "nature of the world, 

 and of bugs!" In this small world we 

 find several different levels of society. 

 The lowest stratum consists of small 

 creatures which burrow in the mud. 

 Scoop up a netful of mud and you will 

 find in the early spring, tadpoles of frogs, 

 nymphs of dragon-flies with huge trap- 

 door jaws. Here they swim about in com- 

 pany with thread-like worms, microscop- 



THROUGH nature education, the joys 

 of hunting with a camera have been 

 extolled as a substitute for hunting with 

 a gun. Even without gun or camera, na- 

 ture hunting may have its lucky shots if 

 out mind's eyes can be trained in marks- 

 manship, alert to see, understand and 

 appreciate the country we are in, and its 

 plant and animal life. 



A rotting log in the woodland is one 

 of the best examples of a self-sufficient 

 community, where each creature is solv- 

 ing somehow the problem of how to 

 make a living. Here are damp moulds, 

 fungi and lichens, food for animal life, 

 among which we find abundantly the 

 little gray pill-bug, humble cousin of the 

 lobster, centipedes untroubled by the 

 thought "to know which leg comes after 

 which," soft white grubs of beetles, cater- 

 pillars of moths, spider eggs in white 

 silken blankets, soft-shelled snails trail- 



ic protozoa, small insects and large pred- 

 atory water beetles, water spiders and 

 snails which attach themselves to sub- 

 merged water plants. Near the surface 

 of the water, amusing waterboatmen ply 

 their feathery oars, and the little back- 

 swimmers dart about in apparent frenzy. 

 Mosquitoes leave the cast-off garments 

 of babyhood upon the surface of the 

 pool, and wing their way. Red-spotted 

 newts poke their noses up for air, and 

 green frogs sit serenely at the margin. 

 Darting above them all are the winged 

 insects, notably the dragon flies, which 

 had their birth in the pool below, and 

 the birds that alight on overhanging 

 branches. 



The greatest interest of a small pond 

 or marsh in the spring is, to my mind, 

 in the various stages one may find of the. 

 development of several kinds of amphi- 

 bia (frogs, toads and salamanders) . The 

 eggs are familiar bunches of brown or 

 blackish spheres enclosed in a mass or 

 masses of transparent jelly. You may 

 identify the species with a Palmer chart 

 which explains the distinguishing char- 

 acteristics of the eggs, and the time of 

 year they are laid. In our eastern woods 

 we may see at the breeding season, which 



tensifying intelligent sexual selection, partly through further 

 reduction of the bony parts consequent upon diminished masti- 

 cation, and partly through the further development of the 

 frontal portion of the skull. The eyes will, it is plain, be rather 

 deeper set, the nose prominent and rather narrow, the mouth 

 still smaller, the chin more prominent, the jaws even more 

 moderate and less regular, the teeth tending to smaller, dim- 

 inished mostly in number, even less regular than now in erup- 

 tion and position, and even less resistant. The future of the 

 beard is uncertain, but no such weakening as with the hair of 

 the head is as yet observable. 



The body will tend to slenderness in youth, the breasts 

 towards small, the pelvis parts but little affected, the lower 

 limbs towards long, the upper rather towards short, the hands 

 and feet towards narrower, the fingers and toes towards more 

 slender, with the fifth toe probably further diminishing. 



As to the internal organs, the only more plainly foresha- 

 dowed probabilities are a further weakening and diminution 

 of the appendix, and a shortening, with diminution in capa- 

 city, of the intestines. As food may safely be expected to con- 

 tinually be more refined and made more digestible, the neces- 

 sity of a spacious large intestine will diminish in proportion. 



Physiologically, the tendencies indicate a rather more rapid 

 than slower pulse and respiration with rather slightly increased 

 than decreased temperature — in other words a livelier, rather 

 than more sluggish, metabolism. But substantial changes in 

 these as well as in other organic functions are not to be anti- 

 cipated for many millenniums; these functions are too firmly 

 established. 



So much for normal conditions. There is, regrettably, also 

 the debit side to be considered. Man has ever paid for his ad- 

 vance, is paying now, and will pay in the future. Functional 



disorders, digestive, secretive, eliminative, disorders of sleep 

 and sexual, can not but multiply with the increasing stresses, 

 exertions and absorptions. Mental derangements will probably 

 be more frequent. Destructive diseases such as diabetes, and 

 various skin troubles, will probably increase until thoroughly 

 understood and hindered. The teeth, the mouth, the nose, the 

 eyes and ears, will ever call for an increased attention. The feet 

 will trouble. 



Childbirth will not be easier nor less painful; though assis- 

 tance will equally rise in effectiveness. Due to prolonged life, 

 heart troubles, apoplexies, cancer, and senile weaknesses of all 

 sorts, will tend to be more common, until mastered by medi- 

 cine. All this, with many abnormal social factors, will retard 

 but not stop man's progress, for the indications are that he will 

 rise equal to all his growing needs as they develop and begin 

 to hurt. 



There is no life-danger to humankind to be apprehended on 

 these scores. If there is a danger to human future, it lies in 

 the birth rate of the torch-bearers. Already now the birth rate 

 in the families of the most intellectual is unsatisfactory. 



To try to fathom what will happen with man in the distant 

 future would be to lose ourselves in unwarranted speculation. 

 Only a few facts seem certain. As man will advance in knowl- 

 edge, so he will advance in the understanding of what is truly 

 advantageous and what truly disadvantageous to him, which 

 will make it easier for him to follow the right road. He will 

 advance in the control of nature, which will aid him greatly 

 in shaping his own destinies. And he will ever more understand 

 disease with its antidotes and immunization. With these gains 

 in perception and power, notwithstanding the many difficulties 

 in the way and the many less fit that must be left behind, a 

 long human progress appears assured. 



