What classifies a mass extinction?

• Only 5% of species go extinct.

• Massive flooding due to hurricanes.

• Happens in a relatively short period of time and is global

• There have never been any mass extinctions on Earth.

Which of the following is NOT an accepted criterion for a mass extinction event?

• The event must have occurred in a relatively short time frame.

• The extinction involves multiple lifeforms and is widespread.

• A significant part of life on Earth became extinct.

• The cause of the mass extinction must be obvious.

Which of the following mass extinctions occurred first?

• Ordovician-Silurian

• End Permian

• Late Devonian

• Cambrian

Which of the following events resulted in the most species extinctions overall?

• Cretaceous-Tertiary

• Ordovician-Silurian

• End Triassic

• End Permian

What is another widely used name for the Cretaceous-Tertiary boundary?

• X1-X2 boundary

• C-T boundary

• K-T boundary

• M-C boundary

The Devonian extinction had the most effect on which community of species that were living at the time?

• Freshwater tetrapods.

• Terrestrial plants.

• Marine reef builders.

• Small mammals.

The Geologic Time Scale is a record of what?

• The known history of rocks and fossils.

• A list of every living thing ever.

• Classification of rocks.

Paleozoic, Mesozoic & Cenozoic are all

• Epochs

• Eras

• Periods

• Eons

Which is the most recent era of time- the one that we are currently in?

• Mesozoic

• Cenozoic

• Paleozoic

• Precambrian

Which Eon or Eons were the longest in Earth history and the one geologist know the least about?

• Tertiary

• Hadean, Archean, Proterozoic

• Phanerozoic

• Silurian