This is a simple demonstration of how easily Evolution accommodates its failed predictions, in what has been referred to as the "
Problem of Homology", (though generally kept concealed and not communicated to the public.)
On the one hand, evolutionists argue that anatomical similarities shared between different species are 'homologs' and provide evidence of evolutionary relationships.
On the other hand, when such 'homologous' features are examined, it turns out that many of the traits in even closely related species are organized in fundamentally different ways during different stages of embryonic development.
In other words, the similar anatomical end-result is arrived at through entirely different developmental pathways.
Evolutionists are thus forced to accommodate a direct contradiction to their basic homology argument. Which is why the "problem of homology" is not advertised. No need to let inconvenient facts get in the way of a great public-relations talking point.
Embryology and common descent
Darwin and later evolutionists have argued that embryology provides powerful evidence for common descent. For at certain stages of embryonic development, widely varying species are remarkably similar. As one paper explains, “This classic observation has long been viewed as an emphatic realization of the principle of common descent.” (Kalinka and Tomancak) The prediction is that while species evolve, some embryonic stages are conserved.
But there are many examples of closely related species with unexpected embryonic differences. For example, Rana fusca of Southeast Asia and Rana esculents of Central Europe are two frog species. The eyes of R. fusca and R. esculents are, not surprisingly, quite similar and naturally are thought to be directly inherited from their common ancestor. Therefore they would be expected to derive from the same genes and the same embryonic development pathway. But R. fusca develops the lens from the epidermis on the optic cup. It is the optic cup that induces the epidermis to differentiate into the lens which ends up perfectly fitting. It makes sense that the lens perfectly fits in the optic cup since it is developing from the epidermis. R. esculents, however, develops the lens without the presence of the optic cup. In one case the optic cup is the inducer, in the other case the optic cup is irrelevant. It can be completely cut out. As Sir Gavin de Beer put it, the lenses in these two closely related species cannot be doubted to be homologous “yet they differ completely in the mechanism by which determination and differentiation are brought about. This is no isolated example.” (de Beer, 13) Indeed it is not an isolated example and de Beer asks: “What mechanism can it be that results in the production of homologous organs, the same ‘patterns’, in spite of their not being controlled by the same genes?” (de Beer, 16)
Another example comes from the tomato (Solanum lycopersicum) and bittersweet (Solanum dulcamara) plants. The pollen-producing anther organs of these closely related species are both arranged as a cone. These cone structures appear only in a single clade within the genus. They would have traditionally been thought to derive from a common ancestor and so have similar embryonic development pathways. But whereas small hairs known as trichomes are required for the cone formation in the tomato, in bittersweet the trichomes surprisingly prevent the cone formation. As one study concluded, “
these two species produce the same macroscopic structure through two mutually exclusive developmental routes and the robust anther cone is derived differently within the clade.” (Glover, Bunnewell and Martin)
Such similar structures, thought to have been inherited from a common ancestor yet developing from dissimilar initial states or different development pathways are “the rule rather than the exception.” (Alberch) As one researcher concluded, “Because there are so many examples of homologous structures arising from nonhomologous development processes, I believe homology can no longer retain its historical links to shared embryonic development.” (Hall)
https://sites.google.com/site/darwinspredictions/embryology-and-common-descent
