The fossil record contains many examples of appearance; that is, fossils of organisms that appeared and remained in a specific location for extended periods of time. what is lacking in the fossil record are those small, incremental changes during speciation. in many cases, scientists have been unable to find these transitional forms. one reason for the lack of transitional fossils is that conditions must be just right for fossils to form. another explanation proposed by scientists is that species are generally stable and rarely change for millions of years. there is then a rapid burst of change, rather than the usual slow-paced evolution, that results in a new species and the transitional form leaves few fossils behind. this rapid change in species that rarely leaves behind fossil evidence is referred to as a) natural selection. b) adaptive radiation c) directional selection. d) punctuated equilibrium.