What is the "missing link" and what have recent finds cause scholars to question?

Missing links, or more properly termed, "transitional fossils," have been discovered and continue to add to humankind’s knowledge of evolutionary changes. The term "missing link" belongs to the old concept of the Great Chain of Being, which holds that simple organisms are primitive versions of complex ones. This was already questioned by scientists with newer theories, an example of which is the theory of Punctuated Equilibrium, in which evolution is characterized by long periods of genetic stability with short periods of rapid evolution in between.