The theory of punctuated holds that the change we can see is evolutionarily
minor and that speciation occurs only in response to major crises or genetic
events. The majority of time, species exist in relative stasis, changing very
little, until a crisis or major genetic event occurs and they undergo rapid
change.
Eldredge and Gould state that their theory is supported by the fossil record,
which shows major evolutionary changes separated by periods of relative
stability.