Johnson next considers in chapter 7 the molecular evidence for evolution. Classification among species has traditionally been accomplished through observation of various visible characteristics. Biochemists have discovered the viability of classifying species at the molecular level by their degree of similarity. Johnson brings attention to the fact that this subject is highly controversial. For instance, molecular studies have led some scientists to classifications that differ greatly from classifications based on visible characteristics. Some scientists ignore this obvious disparity as only an apparent problem and claim this level of classification is more objective. However, when examining frogs at the molecular level, for example, some groups bear more similarity with mammals than with their own species. Additionally, while molecular studies have proven a great degree of similarity between chimps and humans, it does nothing to explain their even greater degree of visible dissimilarity. The study of the molecular evidence has also shed light on a certain chemical called cytochrome c. Based on the study of the levels of this chemical compound found in organisms attempts have been made to measure the degree of divergence between species thought to be in the same ancestral line. Unfortunately, it has been discovered that some plant species differ from bacteria as much as humans do, based on cytochrome c comparisons, rendering comparison of this kind unreliable at best. Other problems faced by biochemists are the questions of the order of appearance of compounds like DNA and RNA that direct the synthesis of proteins essential to the development of life.
Johnson concludes his coverage of the molecular evidence by claiming that, far from proving evolution, it actually adds to the difficulty of explaining evolution by natural selection because it reveals even greater degrees of complexity. Molecular systems are made up of complex parts, many of which rely on other complex parts to carry out their functions. More complexity necessitates an even greater need for empirical evidence for the assertions of the Darwinists. These studies, like others, fail to provide the much needed proofs that a) cumulative micromutational change actually occurs, and b) that common ancestral links actually exist.
Johnson tackles the subject of pre-biological evolution in chapter 8, analyzing how Darwinists account for the appearance of life to begin with.
