New research has uncovered that pollen preserved in 250 million year old rocks contain compounds that function like sunscreen, these are produced by plants to protect them from harmful ultraviolet (UV-B) radiation. The findings suggests that a pulse of UV-B played an important part in the end Permian mass extinction event.
Click here for original story, Sunscreen-like chemicals found in fossil plants reveal UV radiation was involved in mass extinction events
Source: Phys.org