Geologic Time Scale

Reorder

Place the following in order from oldest to youngest.

• Hadean

• Archean

• Proterozoic

• Paleozoic

• Mesozoic

1

2

3

4

5

• 1
• 2
• 3
• 4
• 5

Open Ended

How do scientists organize Earth’s history and what evidence do they use?

Multiple Select

Use the time scale to identify the period in which each organism pictured below lived.

• Cambrian

• Ordovician

• Silurian

• Devonian

Multiple Choice

What do fossilized cyanobacteria from about 3.5 billion years ago indicate?

• They indicate the presence of dinosaurs

• They provide evidence of single-celled organisms

• They show the evolution of mammals

• They suggest a volcanic eruption

Multiple Choice

What evidence do limestone and shale from Kentucky and Indiana provide about the Silurian period?

• They indicate a volcanic eruption

• They suggest a shallow sea covered much of North America

• They show the presence of dinosaurs

• They provide evidence of glacial activity

Multiple Choice

90% of Earth’s history occurred during which era?

• Precambrian

• Paleozoic

• Mesozoic

• Cenozoic

Multiple Choice

Which era is the most recent, the one that we are currently in?

• Mesozoic

• Paleozoic

• Cenozoic

• Precambrian

Multiple Choice

Scientists have found large groups of fossils of marine organisms on mountaintops. What does this tell scientists about the past?

• That these rocks must have been moved there by some one else.

• That these rocks were always above the surface of an ocean

• That these organisms left the ocean and climbed to the top of an inland mountain to die

• That these rocks were once below the surface of an ocean

Multiple Choice

Order the divisions of geologic time from the longest to the shortest.

• eras, eons, periods

• periods, eras, eons

• periods, eons, eras

• 1. eons, eras, periods

Multiple Choice

What is the primary evidence used to study the Precambrian Era?

• Fossils

• Radiometric Dating

• Ice Cores

• Tree Rings