The theory that species evolve during short periods of rapid change is called?

• A. Gradualism
• B. Mold
• C. Punctuated Equilibria
• D. Cast

Answer: (C)

The speed of evolutionary change is being tested here. Some scientists propose that species stay the same for long stretches and then undergo rapid changes during speciation, leading to new species appearing in the fossil record in a relatively short time. This pattern is called punctuated equilibrium. It explains why fossils often show sudden appearances of new forms separated by long periods with little change, contrasting with a slow, steady accumulation of differences.

Mold and cast are types of fossils, not theories about how evolution happens, so they don’t describe the tempo of evolution. Gradualism, on the other hand, argues for slow, continuous change over time, not rapid bursts.