What pattern of evolution is characterized by long stable periods interrupted by brief periods of more rapid change?

The pattern of evolution characterized by long stable periods interrupted by brief periods of more rapid change is known as punctuated equilibrium. This theory, proposed by paleontologists Niles Eldredge and Stephen Jay Gould, suggests that the evolutionary process does not occur uniformly or gradually but rather in quick bursts of significant change following lengthy periods of stability, or equilibrium.

This framework suggests that species remain relatively unchanged for long durations, known as stasis, but when they do evolve, these changes happen rapidly in geological terms, often associated with speciation events, especially as environmental conditions shift. This contrasts with gradualism, which posits that species evolve slowly and steadily over time through a continuous accumulation of small changes.

Punctuated equilibrium helps to explain the fossil record, where species appear suddenly and remain relatively unchanged for long periods, followed by new species emerging rapidly. This model provides a more nuanced understanding of how species adapt and evolve, particularly in relation to environmental changes and mass extinction events, leading to bursts of diversification.