4-5: Geologic Time Scale

In which time period are we currently living?

• Precambrian Time

• Paleozoic Era

• Mesozoic Era

• Cenozoic Era

Dinosaurs, small mammals, and birds are found in this time period.

• Precambrian

• Paleozoic

• Mesozoic

• Cenozoic

Which era was the longest, taking up 88% of geologic time?

• Precambrian

• Paleozoic

• Mesozoic

• Cenozoic

The end of an era, and the end of life for groups of organisms, is called?

• Death

• Mass extinction

• Transition

• Turning point

The end of the Mesozoic Era was most likely caused by?

• A meteor

• Too much oxygen

• Lowering sea levels

• An ice age

Which is the youngest rock layer?

• Siltstone

• Conglomerate

• Mudstone

• Limestone

Which time period is the longest?

• Precambrian Time

• Paleozoic Era

• Mesozoic Era

• Cenozoic Era

How many eras make up the geologic time scale?

• 3

• 4

• 5

• 6

What is the most recent PERIOD of geologic time?

• Mesozoic

• Cenozoic

• Miocene

• Quaternary

Which of the following organisms appeared first in geologic time?

• mammoths

• primates

• fish

• dinosaurs