|Editor's Introduction -- A middle-school "science" textbook dispenses pseudoscientific drivel, and the book's alleged "author" refuses to answer written inquiries about it.|
This article appeared in The Textbook Letter for May-June
accompanying reviews of Life Science: The Challenge of Discovery
(a middle-school book published by D.C. Heath and Company).
Linda A. Warner Lays an Egg
William J. BennettaFigure 12-4 in Heath's Life Science shows two fish spawning, and the caption says: "There is a good chance that many eggs will not be fertilized." The book doesn't say what "many" or "a good chance" may mean, so the caption really is just pseudoscientific drivel. As far as I can tell, its only purpose is to promote the discredited notion of "nature's ladder." As far as I've been able to learn -- even by writing to Linda A. Warner, who is said to be the book's first author -- the caption has no basis in fact. I'll say more about Warner later, after I tell a little about fishes.
Among the species of fish that commonly spawn in captivity -- i.e., the species for which we have the most reliable information -- fertilization rates typically run at or near 100%. It is rare for any eggs, let alone any significant percentage of a batch, to be left unfertilized. This is well known among aquarists, fish-breeders and scientists, and it explains (I believe) why fertilization rates are rarely mentioned in published reports about spawnings. Such rates don't constitute an important variable, because fertilization always proceeds with perfect or near-perfect effectiveness.
My statement about published reports is based upon my own survey of the pertinent literature. I began by searching through the classic compendium Modes of Reproduction in Fishes, issued in 1966 by The Natural History Press (Garden City, New York). In accounts of thousands of species, I found exactly five references to fertilization rates; in each case, the rate was 100%.
Looking at other sources, I found only these items:
Maybe, however, I had missed something. Maybe there existed some information, somewhere, that could lend a wisp of support to Heath's caption. With that in mind, I wrote to the first author shown on the title page of Heath's book: "Linda A. Warner, Middle School Master Science Teacher, Laboratory School, University of Northern Colorado, Greeley, Colorado." In fact, I wrote to Warner three times, by certified mail, asking her to cite the scientific literature on which she had based her claim about "a good chance that many eggs will not be fertilized." She did not reply.
I infer, then, that Heath's caption is just a case of ladder-peddling. Because they regard fishes as "low" and contemptible, ladder-peddlers are sure that fishes' reproductive mechanisms are clumsy and inefficient; the religion of the ladder demands that this be true, so there is no need to study the matter. Similarly, ladder-peddlers know that reproduction in the human -- the species that perches at the top of the ladder and is the biblical god's favorite -- must be a marvel of efficiency. But the peddlers are wrong about that, too.
When a female human is born, her ovaries carry 1 million to 2 million primary oocytes -- cells that have the potential to develop into eggs. More than half of these cells, however, degenerate before the female becomes sexually mature; only a few hundred thousand remain viable during puberty and later life. Of those few hundred thousand, only a few hundred ever become eggs and move to the Fallopian tubes, where fertilization may take place. And out of those few hundred, only two dozen or so can actually be fertilized, even in a female that breeds as often as is possible.
If, therefore, we want to cite an animal in which the utilization of oocytes or eggs is ineffective -- spectacularly ineffective -- we should point not to a fish but to our own kind. So much for the ladder-peddlers.
William J. Bennetta is a professional editor, a fellow of the California Academy of Sciences, the president of The Textbook League, and the editor of The Textbook Letter. He writes frequently about the propagation of quackery, false "science" and false "history" in schoolbooks.