Unit E Lesson 11 Geological Time Scale

Modern mammals was during this era:

• Cenozoic
• Mesozoic
• Paleozoic

The earliest part of Earth's history is called the:

• Cenozoic
• Cambrian
• Holocene
• Precambrian

Trilobites serve as good _________ for various intervals of the Paleozoic era. This is because these species lived during a specific time span. 

• Index fossil
• Mammals

After Precambrian time, Earth's history is divided into three eras, beginning with the

• Paleozic Era
• Mesozoic Era
• Cenozoic Era

What is a mass extinction?

• when there was no water
• when many species evolve
• when the Earth was formed
• when many types of species die out

Humans evolved during the . . .

• Paleozoic Era

• Cenozoic Era

• Precambrian Time

• Mesozoic Era

The longest piece of earth's history was during . . .

• the Mesozoic Era

• the Precambrian Time

• the Paleozoic Era

• the Cenozoic Era

Which time frame, below, do we know the least about???

• Ceonzoic Era

• Mesozoic Era

• Paleozoic Era

• Precambrian Time

Paleozoic, Mesozoic & Cenozoic are all

• Epochs
• Eras
• Periods
• Eons

Based on the geologic time scale, how old is the Earth?

• 4.6 billion years

• 54.5 billion years

• 4.6 million years

• 5 billion years