This handout examines the evidence for the theory that a massive meteor impact caused the mass extinction at the end of the Permian Period.  This is the worst mass extinction known to geologists, and 90% or more of all species on Earth were wiped out.

It is part of a set of four articles on possible causes of the Permian and Cretaceous mass extinctions can be used to organize classroom debates or to have students compare and contrast the events and their causes.