An hypothesis for the extinction of the dinosaurs is that the earth had been hit by a gigantic meteor that caused the death of those big reptiles. In that case the entire genetic pool of those animals has been destroyed, invalidating the Hardy-Weinberg equilibrium. In Genetics what is this type of gene frequency change called?
A phenomenon in which a large number of genes is introduced or destroyed in a population is called genetic drift. When genetic drifts take place the Hardy Weinberg principle is not applicable.