However, the fossil record displays patterns that are not expected under common ancestry. This includes the appearance of the higher metazoan taxonomic categories before the lower categories and patterns of saltations followed by statis. This brings about issues of controversy. Despite this finding, this is not always the case, as fossils which do not match the fossils are scarcely discovered. Coyne stresses on the fossil record in this chapter are based on convergent evolution. As he states, “[E]volutionary change, even of a major sort, nearly always involves remodeling the old into the new.
The legs of land animals are variations on stout limbs of ancestral fish. The tiny middle ear bones of mammals are remodeled jawbones of their reptilian ancestors. The wings of birds were fashioned from the legs of dinosaurs. And whales are stretched-out land animals whose forelimbs have become paddles and whose nostrils have moved atop their head” (p. 53). This reveals that the evolutionary change involves divergent anatomical and molecular structures in the present and ancestry organisms. This is triggered by the traits that emerge over time thus making the evolved off springs different from their parents and the common ancestor.
Despite his fact, the organisms are still linked to a common ancestry. Chapter three: Remnants: Vestiges, Embryos, and Bad Design This chapter discusses features in animals such as vestigial features, embryos, atavisms, reactivated dormant genes, organs, and limbs. This chapter answers questions of how ancestral creatures looked like. This chapter explains that if an organ is not used, it diminishes as generations go by due to being wasteful and loss of energy. This is explained in the eyes of cave animals, wings in birds and penguins, human beings vestigial tails and hairy bodies.
To sum this up, I have leant that unused genes are turned off in organisms, thus making some vestigial features diminish. However, all organisms have inactive/ dormant genes that make up for vestigial features, and in only take a switch to make them have the features. This explains atavism. This is evident in the examples given of an infant born with a tail or an individual who is hairy. I believe that this point about evolution is true, based on the evidence given, I believe that a man once had a tail, but as time progressed, the tail went on decreasing till it was no more.
This is because the dormant genes were deactivated due to no use at all (Coyne, 2009).
ReferenceCoyne, J. A. (2009). Why evolution is true. Oxford: Oxford University Press.