Letter to the Editor

Re: Knobloch's colums on Biology
Wm. J. Tinkle

In the Biology column of the journal, Dr. Irving W. Knobloch has been giving us interesting facts concerning the changes which occur in plants and animals but his interpretation seems uncertain. He does not make clear how his articles fulfill the purpose of the A. S. A. as stated on the inner cover of the journal, "to study those topics germane to the conviction that the frameworks of scientific knowledge and a conscrvative Christian faith are compatible".

While Dr. Knobloch has cited a number of facts, yet a few more will help in the interpretation. Shanti Batra reports the doubling of chromosomes in muskmelons, (Journ. of Heredity V. 43, no. 3, p. 141 ff) and since his results are so characteristic of tetraploids in general they are worthy of note. The plants in which the chomosonies had been doubled by the applica tion of colchicine had larger leaves, flowers, and stornates than normal plants and the stem diameter was greater, hence these tetraploids are called "gigas". Yet the gain is more apparent than real, for the growth rate is slow, making the plant as a whole only half the size of the normal diploid, the fruits are small but sweet, and the number of viable seeds is only 24 per cent of the diploid seed number. Similarly tetraploid tomatoes and jimson weeds, Datura, are not so tall as diploid plants and bear fewer seeds. Consequently tetraploids find difficulty in becoming established in nature, although they might do so where the vegetation has been destroyed, but they tend to contribute nothing which is evolutionary superior. As for haploids, triploids, and plants with one extra chromosome, these produce types other than their own if they have enough vigor to reproduce at all, and are most likely to produce diploids.

, Hybridization may combine genes in new groupings but since no new genes are formed, the amount of change afforded is limited. Another limitation, which Dr. Knobloch mentions, is the inability of some species to cross. But it is hard to speak of species as long as there is no standard as to whether a certain group is a variety, a species, or a genus, different taxonomists classifying them differently. The term "fixity of species" has no meaning until we have fixed a definition for the word species.

Dr. Knobloch recognizes that genes have great stability and, like other biologists, mentions no mutant which is a benefit to the plant or animal unless the environment changes. Yet since genes do not change gradually but only by the metamorphosis which we call mutation, it is hard to see how evolution could progress far without mutation. New and improved genes would be needed.

Considering these facts, most members of the A. S. A. believe that the variations in living things have increased the types and varieties (species also perhaps if we could agree on a definition) enabling organisms as they migrate to fit into new niches in the habitat. Other changes seem to be fortuitous losses which tend to be eliminated by natural selection.

Dr. Knobloch does not indicate whether he interprets changes thus or whether he believes Amoeba changed to Homo by innate properties and natural forces. Accepting this doctrine (evolution) entails relinquishing or reconstructing our belief in the Bible. The literature of the A. S. A. has set forth the facts of nature which do not agree with the doctrine of evolution. No writer is forced to agree with this literature, but he should mention it, and if he disagrees, state why. We tend to go back to the starting point too often.

But some one will object that evolution does not necessarily mean a simple animal changing to a complex one, but change of any degree in any direction. The A. S. A. convention of 1954 decided that the latter idea should be called not evolution but variation. Of course Dr. Knobloch is at a disadvantage for he was not present at the convention.

Sincerely yours,
William J. Tinkle

Albany, Indiana
March 23, 1955