Transcript Day 31

Day 31
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.
Daily Warm-Up Exercises
1
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.
2
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.
3
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
4
Add Grand Canyon Rocks
Add these rock layers to your time line.
Label and color each area.
Paleozoic Era
Triassic
Period
Kaibab
Formation
Permian
Period
Pennsylvania
Period
Toroweap
Formation
5