We are not really certain of the mwechanism involved in such reversals. As it turns out , 2 of the big 5 extinction events were also correlated to a polar reversal at the same (geologic) instant. That has led to the theory that polar reversals are associated with deep welling of magma and new vulcanism (These are possibloe events that trigger the poles to wander more quickly than our present speed of 50Km /yr).
Magma upqwelling releases a competing pole and e lose our dipole for a period of time. (It may be that because magma upwelling can break outr on the surface, this apparent association of magama and polar reversals may only be an artifact, not a cause and effect.
So, with 2 of the big 5 extinctions associated with polar reversals (as qwell as incresed vulcanism), the die outs may not really be related anyway.
HOWEVER, sea creatures , like radiolarians ARE very susceptibloe to polar changes and, instead of dying out, they merely evolve into a form that reflcts the change of the poles. (Most radiolarians have thee tint shells with unique twists and patterns)
We use radiolarians as key indicators for oil exploration