This seems entirely in harmony with Stephen Jay Gould's theory of punctured equilibrium. [1] "Punctuated equilibrium (also called punctuated equilibria) is a theory in evolutionary biology which proposes that once species appear in the fossil record they will become stable, showing little evolutionary change for most of their geological history. This state is called stasis. When significant evolutionary change occurs, the theory proposes that it is generally restricted to rare and geologically rapid events of branching speciation called cladogenesis."

Species experience perturbations in their genetic expression constantly but these only evolve into stable changes when the environment changes to require it.

[1]https://en.wikipedia.org/wiki/Punctuated_equilibrium