7. In contrast, the evolution model of punctuated equilibrium suggests that evolutionary change occurs in relatively short bursts followed by long periods of little-to-no evolutionary change. This model suggests that mutations in several genes would produce changes in one or several traits in a population. These changes would be so dramatic, however, that they would produce a new species within a fairly short time. It would happen within several generations. In the example, one or more mutations would lead to the sudden appearance of large beak size among individual birds in a population. This would produce a new species-Species B. Following this short period of rapid change, almost no major evolutionary changes would take place among this species for a very long period-perhaps thousands of years.