Eyeing Evolution

No “sequence of fossils by itself” can “demonstrate whether Darwinian mutation and natural selection can and did evolve genuine biological novelties (new structures or body plans),” argues Leonard Brand (Faith, Reason, & Earth History, 281). Some other sort of evidence is needed.

Brand doesn’t find such evidence in standard biology textbooks: “There is abundant evidence supporting the reality of microevolution and speciation. They also discuss patterns of the fossil record, biological adaptations, and a large amount of other material they incorporation in explanations of mega-evolutionary processes.” Yet, “careful analysis of these explanations reveals that they are dependent on the assumption that life is the result of megaevolution” (281-2). Explanations presuppose the theory they are supposed to demonstrate.

Like many others, Brand points to the eye to illustrate the problems: “The eyes of vertebrates are fantastically complex. Octopuses have eyes that rival the vertebrate eye for complexity. Vertebrates and octopuses obviously did not get their eyes from a common ancestor with complex eyes. . . . Could these two types of sophisticated eyes have evolved independently? One can find animals with eyes of many different levels of complexity, line them up in a sequence of increasing complexity . . . and argue that this sequence demonstrates the origin of complex eyes from simple eye spots by evolution. But since there are still huge biochemical and structural differences between these types of eyes, the question remains: Do we actually have evidence that the more complex eyes could and did arise by evolution, or is that an untested assumption?” (282-3).