A study by Dr. Joseph Meert — Professor in the Department of Geological Sciences — and his colleagues suggests an unstable magnetic field may provide an explanation for major evolutionary changes at the end of the Ediacaran Period (542Ma). Read more about their study in a recent article featured in Science Magazine, “Hyperactive magnetic field may have led to one of Earth’s major mass extinctions.” The original research article is currently in press in Gondwana Research — “Organisms with the ability to escape UV radiation would be favored in such an environment.”
Reference
Meert, J.G., Bazhenov, M.L., Levashova, N.M., Landing E., Rapid changes in magnetic field polarity during the Late Ediacaran: Linking the Cambrian Evolutionary Radiation and increased UV-B radiation, Gondwana Research, doi://10.1016/j.gr.01.001
Those with UF Gatorlink access can read the in press article here.