This may be illustrated by looking back to the common origins of parts of bat wings, seal flippers, horse forelimbs and human arms. This parallel illustrates that it is not so radical but more of a change in emphasis. Acknowledgement is made regarding the importance of natural selection and Gould and Lewontin are in agreement that certain structures, such as the vertebrate eye, must have come about through this physical process. There is no other possible explanation. For example, an animal may possess an elaborate appearance to make it attractive to the opposite sex but not to such an extent as to prevent it fleeing from predators.
Some compromise has to exist.
Having looked at some evolutionary theories, this essay will now concentrate on a particular area for discussion - language. This is not referring to external languages such as French, English or Japanese. These are only symbols used to transmit feelings and emotions. The area in question is that relating to the universals that form the basis for the theories of universal grammar. Debates may occur as to whether language exists because of our physiology or our culture.