1. Daily Warm-Up Exercises
Day 30
About how long has Earth existed?
Earth has existed for about 4.5 billion years (or 4,500 million years).
About how long have human beings (Homo sapiens) existed?
Humans have existed for about 200,000 years.
How much is a million?
1000 times 1000
How much is 4,500 million?
4,500 times 1000 times 1000, which is 4,500,000 times 1000
How much is 200,000?
200 times 1000
Daily Warm-Up Exercises
Daily Warm-Up Exercises

2. Daily Warm-Up Exercises
Essay Question
What have you learned so far about time lines? (Use Day 30 & 31)
Earth has existed for about 4.5 billion years (or 4,500,000,000). Humans have existed for about 200,000 years. This represents a small fraction of Earth’s geologic history. Earth's history is divided into eras, and eras are divided into periods. The present is usually at the start of the time line.
Daily Warm-Up Exercises 2
Daily Warm-Up Exercises 2

3. VERY IMPORTANT!!! Scale: 1 million years = 1 millimeter
All measurements must be made from the Now line.
The zero end of the ruler must always stay on the Now line.
Daily Warm-Up Exercises 3

4. Mark Eras
When you finish all the periods, go back and draw a heavy line to mark the beginning of each era.
Label the era by writing its name across the periods.
Daily Warm-Up Exercises 4

5. Add Grand Canyon Rocks
Turn to Rocks Over Time, on page 52 in your lab notebooks.
This table lists the time periods during which these rock layers formed.
For example, the ocean in which the Kaibab Formation was deposited existed between 260 and 255 mya.
How long did the Kaibab Sea exist?
5 million years
Daily Warm-Up Exercises 5

6. Add Grand Canyon Rocks Add these rock layers to your time line.
Label and color each area.
Daily Warm-Up Exercises 6

7. GC Rock Layers and More
Add appropriate details to limestone, shale, and sandstone layers.
Label and color each area.
Add fossil pictures (EH Resources p.41), and Earth’s major geologic events.
Daily Warm-Up Exercises 7