This refers to a theory in evolutionary biology which states that the origin of a new species is usually an abrupt process that cannot always be fully traced by scientists. It is generally used to explain the absence of fossil evidence of intermediate species to prove the gradual evolution of various species. The idea was first proposed by American biologists Stephen Jay Gould and Niles Eldredge in their 1972 paper “Punctuated equilibria: an alternative to phyletic gradualism”. Gould and Eldredge argued that the history of a species generally shows a remarkable amount of stability which is then punctuated by periods of rapid change.