Ch 11 Geologic Time

Longest units of geologic time

• epoch
• eon
• generation
• period

Second-to-longest geologic time period.  Eons are divided into these.

• eras
• eons
• epochs
• periods

Eras are divided into these.

• hours
• periods
• eons
• epochs

Periods are subdivided into...

• eras
• eons
• epochs
• hours

All geologic time periods are equal in length

• true
• false

Older rock contains more complex fossils than younger rock.

• true
• false

Geologists use sudden changes in the _____________ to mark divisions in geologic time.

• environment
• fossil record
• life forms
• weather

Sudden changes in the fossil record represent...

• mass extinction
• evolution of species
• many earthquakes
• flooding of earth

There have been _____ mass extinction events in Earth's history.

• 3
• 4
• 5
• 2

In what period did the largest mass extinction event take place?

• Cretaceous
• Jurassic
• Cambrian
• end of the Permian