Just about every book about evolution points to the hand and foot structure of tetrapods —that is, land-dwelling vertebrates—as an example of homology. Tetrapods have five digits on their front and rear feet. Even if these do not always fully resemble fingers or toes, these creatures are still regarded as pentadactyl (having five digits) because of their bone structure.
The hands and feet of a frog, a lizard, a squirrel or a monkey are all of this kind. Even the bone structures of birds and bats agree with this basic design. Therefore, evolutionists claim that all these life forms are evolved from a single common ancestor and for long, they regarded the phenomenon of pentadactylism as evidence of this. In our own time, however, it was realized that this claim actually lacked any scientific validity.
Even evolutionists admit that pentadactylism is a characteristic found in different living groups among which they cannot construct any evolutionary relationship. For example, in two separate articles published in 1991 and 1996, the evolutionist biologist M. Coates states that the phenomenon of pentadactylism emerged on two separate occasions, independently of one another. According to Coates, a pentadactyl structure emerged in both Anthracosaurs and in amphibians, quite independently of each other.164 This finding indicates that pentadactylism cannot represent any evidence for the hypothesis of a common ancestor. (See Common ancestor.)
Another difficulty for the evolutionists is that these vertebrates have five digits on both their front and hind feet. Yet nowhere in the evolutionist literature is it suggested that front and back feet developed from a common ancestor and it is not hypothesized that they then developed independently. Therefore, we would expect front and back feet to have different structures as a result of different random mutations.
[T]he forelimbs of all terrestrial vertebrates are constructed according to the same pentadactyl design, and this is attributed by evolutionary biologists as showing that all have been derived from a common ancestral source. But the hind limbs of all vertebrates also conform to the pentadactyl pattern and are strikingly similar to the forelimbs in bone structure and in their detailed embryological development. Yet no evolutionist claims that the hind limb evolved from the forelimb, or that hind limbs and forelimbs evolved from a common source. . . . Invariably, as biological knowledge has grown, common genealogy as an explanation for similarity has tended to grow ever more tenuous. . . . Like so much of the other circumstantial “evidence”” for evolution, that drawn from homology is not convincing because it entails too many anomalies, too many counter-instances, far too many phenomena which simply do not fit easily into the orthodox picture. 165
The real blow to the claim of five-digit homology, so long propagated in evolutionist publications, was dealt by molecular biology. The hypothesis collapsed when it was realized that finger structure was controlled by different genes in different species with a pentadactyl digit structure.