Page sixteen 



EVOLUTION 



February, 1931 



Question Box 



Answers by Allan Broms, unless otherwise credited 



NIAGARA VERSUS CHICAGO 



Q. In your "Story of Niagara" you 

 claim the Falls are cutting upstream to- 

 wards Lake Erie. When it cuts way 

 through, will it not lower the Great 

 Lakes and leave all the lake cities, that 

 are now quarreling with Chicago over its 

 drainage canal, high and dry? — J. P. C. 



A. Maybe, as far as lowering the out- 

 let and therefore the surface of Lake 

 Erie is concerned. This may cause a 

 temporary waterfall or rapids in the De- 

 troit River outlet of Lake Huron, but 

 the stream would soon clear away the 

 glacial moraine material which makes the 

 barrier there. Lake Huron and Lake 

 Michigan, would then also be lowered. 



The problem is complicated by a tilt- 

 ing of the earth-crust now going on in 

 the Great Lakes area. The northeastern 

 portion is rising, a movement that has 

 been in progress ever since the glacial 

 ice sheet retired froni this region, so re- 

 lieving the pressure on the crust, most 

 recently of course in the northeast. The 

 north shore of Lake Ontario, for in- 

 stance, is rising faster than the south 

 shore, which is being slowly submerged. 



The Niagara lakes outlet is thus slowly 

 rising in a sort of nip and tuck race with 

 its erosional deepening. If the rising is 

 faster than the deepening, the level of 

 the Great Lakes above it will also rise, 

 perhaps enough to flood Chicago (solv- 

 ing the problem of its drainage canal) 

 and drain southwest to the Illinois and 

 Mississippi rivers as they did once before 

 when the banking ice sheet to the north- 

 east prevented eastward drainage. TTie 

 race, therefore, is really between the Ni- 

 agara and Chicago outlets, with the ulti- 

 mate, result uncertain. But whatever the 

 fate of the lake cities, let it not effect 

 your sense of real-estate values, for it is 

 all far in the future and some human 

 channel-deepening at Niagara or a few 



well placed stone embankments along 

 the lake fronts could easily thwart this 

 leisurely upheaval by Nature. 



THE "MISSING LINK" AGAIN 



Q. I have heard a lot about the 

 "missmg link." What is it? — A. K. S. 



A. Objectors to evolution have per- 

 sistently argued that there is some "miss- 

 ing link" between man and his animal 

 ancestors. The term has been loosely 

 and variously used to mean either some 



Gorilla, 

 intermediate ape-man supposed to be 

 lacking, or the presence or absence of 

 some distinctive organ marking man 

 apart from the apes. 



Before 1892, when the fossil remains 

 of the Java ape-man. Pithecanthropus 

 erectus, were found, the first objection 

 had some point. But now we have not 

 only this half-human fossil, but a whole 

 connecting series, those above the Java 

 type, such as the Peiping, Piltdown, 

 Heidelberg, Neanderthal and Cro-Mag- 

 non men, and below it the manlike ape 

 of Taungs. Consequently, only the most 

 Ignorant now talk of such a missing link. 



But so-called "missing links" of the 

 other sort pop up from time to time. 

 Typical is the claim that "man has no 



tail," it being assumed that apes have 

 tails, which happens to be untrue. All 

 that apes have are some bony remnants 

 of a tail, but if that gives them a tail, 

 then man has it, too, for he has similar 

 remnants. Also many attempts have been 

 made to find something distinctive 

 about the human brain. Back in 1863, 

 Huxley had to prove that the "hippo- 

 campus minor of the posterior comu of 

 the lateral ventricle," a little himip with- 

 in the inner cavity of the human brain, 

 also existed in the apes, that being the 

 "missing link" according to Fundament- 

 alist objectors of his day. More recently, 

 the ape has been credited with an extra 

 fold in the back of his brain, called by 

 the Germans the "Affenspalte" (apei 

 fissure) and said to be lacking in man, 

 which made it at once in some way im- 

 portant. But G. Elliot Smith showed 

 that it does occur in man, but usually 

 only on the left side (associated with 

 right-handedness) and that the brain 

 casts of several early fossil men also 

 show it, in the case of the Java ape-man 

 on the right side, indicating that he was 

 left-handed. The human brain really is 

 somewhat more finely wrinkled than the 

 ape's, but this we would expect, the sig- 

 nificant thing being that the general pat- 

 tern of the brain folds is quite the same. 

 The only real gap in man's whole 

 pedigree is that between the first fishes 

 and their immediate ancestors who 

 lacked a backbone. But even here we 

 have good theories, the only trouble be- 

 ing that we have two of them. However, 

 the "missing link" objectors will find no 

 comfort here, for that gap is too far 

 back in our ancestry to save us from our 

 obnoxiously close kinship with those ugly 

 apes. The evidence of that kinship b 

 much too overwhelming when we con- 

 sider all we have in common in bodily 

 structures, chemical functioning, embry- 

 onic development and now those most de- 

 cisive blood tests. Besides, the "missing 

 link" is actually not missing. 



of heat or cold applied in treatment have little or no effect. 



Thus the study of the physiology of mutation-production 

 is opening up, though as yet in a very empirical stage. And 

 meanwhile, X-rays and their relatives remain the only p-ime 

 cause of mutations yet known. 



Since, now, mutations in general bear all the earmarks of 

 the X-ray mutations, then, even though most of them have 

 not actually been produced by radiation, it seems legitimate 

 to use the readily obtainable X-ray (radium, etc.) mutations 

 as the handle by which to study their nature. These X-ray 

 mutations are certainly accidental, being produced by ultra- 



microscopic events, not individually controllable, that take place 

 without reference to the outcome or the advantage for the 

 organism. The natural mutations — the majority of which can 

 be reinvoked by X-rays — are on the average equally as detri- 

 mental, and of the same nature, so far as their effects are con- 

 cerned, as the X-ray mutations. Can we then escape the con- 

 clusion that they are accidental in the same sense, and that 

 specific mutations are therefore not dictated by any "adaptive 

 reactions" or other specific respcinses of the organism to climate 

 or to any other features of its mode of life? 

 (To be concluded) 



