Some Things in Biology Don't Make Sense in the Light of Evolution

Some Things in Biology Don't Make Sense in the Light of Evolution Jonathan Wells and Paul A. Nelson Introduction In 1973 Theodosius Dobzhansky wrote in the The American Biology Teacher that "nothing in biology makes sense except in the light of evolution."1 This aphorism has been repeated many times since, mainly by educators who feel that evolution provides the only proper framework for teaching biology. By evolution Dobzhansky meant that "life arose from inanimate matter only once, and that all organisms, no matter how diverse in other respects, conserve the basic features of the primordial life."2 He also meant the neo-Darwinian theory of how this occurred: "The only explanation that makes sense is that... the environment presents challenges to living species,... [and] natural selection may cause a living species to respond to the challenge by adaptive genetic changes."3 Dobzhansky contrasted this with the antievolutionist view that "all existing species were generated by supernatural fiat a few thousand years ago, pretty much as we find them today." But antievolutionists either "are ignorant of the evidence or are resistant to evidence, owing to emotional blocks or to plain bigotry." The evidence , according to Dobzhansky, includes the fossil record, the universality of the genetic code, similarities among early vertebrate embryos, and biogeographic patterns such as the distribution of fruit fly species on Pacific islands. Dobzhansky argued "that all these remarkable findings make sense in the light of evolution; they are nonsense otherwise."4 Now, a quarter of a century later, there is mounting evidence that Dobzhansky's sweeping claim was mistaken. Of course, everyone agrees that Darwin's theory works well at some levels. We can select variations to produce descent with modification within domestic species; we can observe selective changes in antibiotic and pesticide resistance in wild species; and a similar process probably contributed to the diversification of closely related species in the wild (such as fruit flies on Pacific Jonathan Wells is a Research Fellow in the Discovery Institute Center for the Renewal of Science and Culture in Seattle, Washington. Paul A. Nelson is a Research Fellow in the Discovery Institute Center for the Renewal of Science and Culture, and is the editor of the journal Origins & Design. © Rhetoric & Public Affairs Vol. 1, No. 4,1998, pp. 557-563 ISSN 1094-8392 558 Rhetoric & Public Affairs islands). But Darwin (and Dobzhansky) believed that the same process, given enough time, could account for the evolution of all living species from one or a few common ancestors. Here, the theory is encountering serious problems with the evidence , as the following examples illustrate. Patterns of Biological Evidence that Challenge Neo-Darwinism (1) Genetic Variations. In order for natural selection to produce evolution, a population must include suitable genetic variations. No one doubts that natural populations include variations, but are they the kind which can lead to large-scale evolution? Modern research on the genetic basis of adaptation suggests that they are not. Geneticist John McDonald considers this "a great Darwinian paradox," since those genes "that are obviously variable within natural populations do not seem to lie at the basis of many major adaptive changes," while those that "seemingly do constitute the foundation of many, if not most, major adaptive changes apparently are not variable within natural populations."5 In other words, the variations we see are not the ones Darwin's theory needs, and the ones it needs we do not see. (2) Genetic Programs. Neo-Darwinism assumes that organisms develop according to genetic programs; mutations in developmental genes would then provide the raw materials for evolution. When molecular biologists recently discovered that animals as different as mice, flies, and worms have similar developmental genes, many considered this a confirmation that these animals had inherited their genetic programs from a common ancestor. Other biologists, however, see a profound puzzle: If genes control development, how could similar genes make animals as different as mice, flies, and worms? Embryologists John Gerhart and Marc Kirschner call this yet another "paradox," and suggest that evolutionary biologists have been "looking in the wrong place."6 If genetic programs do not control development, how could genetic changes account for evolution? The lack of suitable variations...