Which statement describes punctuated equilibrium?

• A. A short rapid change only.
• B. Evolution proceeds only through gradual accumulation of small changes.
• C. Proposes long stable periods interrupted by brief periods of more rapid change, then introducing new species.
• D. The carbon cycle drives the speed of evolution.

Answer: (C)

Punctuated equilibrium describes evolution as happening in fits and starts: long periods with little or no change, followed by brief, rapid bursts of change that can create new species. This pattern fits how some fossil records show sudden appearances of new forms rather than a smooth, continuous ladder of change. The rapid bursts are often tied to events like small, isolated populations or environmental shifts that create new selective pressures, making evolution happen faster during those times. In contrast, evolution isn’t described as always gradual, and it isn’t driven by something like the carbon cycle defining the speed of change. That combination—long stasis with quick bursts leading to new species—best captures punctuated equilibrium.