24. History of Life on Earth

How do mass extinctions differ from background extinctions?

What could be one reason why paleontologists mostly study extinctions in the Phanerozoic (since the Cambrian explosion)?

What is thought to have been the major cause of the end-Permian extinction event?

The extinction at the end of the Cretaceous period is most closely associated with what?

Which piece of evidence is consistent with the leading hypothesis for the cause of end-Cretaceous extinction?

During the late Pleistocene, between 50,000 and 10,000 years ago, about 65% of megafauna species (animals with mass over 44 kg, or 100 lb) went extinct around the world. Australia and the Americas had the highest megafauna extinction rates with 100% of mammals over 1000 kg (~2,200 lbs) going extinct. Many scientists consider these extinctions as the leading edge of the world’s 6th major extinction event. If the causes of the late Pleistocene extinctions and the causes of the 6th major extinction event are linked, which of the following statements about the Pleistocene extinctions is most likely true?