Question

Scientists developed the ________ model after their studies of the fossil record revealed that some species appear quite suddenly and then remain essentially unchanged phenotypically for a long period of time.

Answer 1

Punctuated Equilibrium

Step-by-step explanation:

The phyletic gradualism model and the punctuated equilibrium are aspects models of macroevolution that are characterised with varying patterns.

However, the punctuated equilibrium model of evolutionary history consists of geologically long periods of inactivity (stasis) with little or no evolution, interrupted or "punctuated" by geologically short periods of rapid evolution.