punctuated equilibrium
noun [ U ] biology specialized uk/ˈpʌŋk.tʃuː.eɪ.tɪd iː.kwɪˌlɪb.ri.əm/ us/ˈpʌŋk.tʃuː.eɪ.t̬ɪd iː.kwɪˌlɪb.ri.əm/
（进化论理论）间断平衡说
a theory of evolution that claims that change happens suddenly over short periods of time followed by long periods of no change