Discussion Questions: Permian-Triassic Extinction

Discuss the kind of fossil evidence that Dr. Ward uses to determine the severity of the P-T extinction.

What kinds of evidence led Ward to conclude that most animal life was absent during the time when certain rock layers were formed? How, specifically did he conclude that animals were absent, rather than simply not getting fossilized?

Discuss the various hypotheses that attempt to explain the severity of the P-T extinction. What kind of evidence exists to test those hypotheses. Are those hypotheses mutually exclusive?