 Rocks and minerals are the natural
resources that supply our everyday
needs!
 Rocks and minerals tell the physical
history of the Earth and its life history.
• Timeline
• Scale model
• Geologic time scale
• Chronological
• Million years ago(mya)
• Billion years ago (bya)
• Time interval
• Eons
• Eras
• Periods
• Epochs
• Proterozoic
• Phanerozoic
• Paleozoic
• Mesozoic
• Cenozoic
• Fossil evidence
• Simple life
• Complex life
• Evolution
1. A TIMELINE is a scaled model that
chronologically records when things
happened in the history of something.
2. How to start?
3. First, set up the scale of YOUR
timeline from start to finish!!!
Can START or
end HERE @
BIRTH
Can START
or END
HERE @
TODAY
Your age or the year when things happened is 
one scale that starts at birth
 How many years ago things happened is another scale
that starts at today
A TIMELINE is a scaled model that
chronologically records when things
happened in the history of something.
1. First, set up your scale for your lifetime (so far!!)
2. If 20cm = 15 years, how many cm per each year in
your timeline?
3. Set up the equation first with Model/Real
M = x cm = 20cm
R
1 yr
15 yrs
4. Then solve for x to set up your personal timeline
x = 1.33 cm model = 1 yr real
For you, 1.3cm/yr
YOURS through 15 years ago
For me (or your grandma!),
M = x = 20cm
so, x = 0.33 cm/yr
R
1 yr
~60 yrs
ZOIC means LIFE
(like “ZOO”)
CENOZOIC
MEANS
RECENT LIFE
MESO ZOIC
MEANS
MIDDLE LIFE
PALEO ZOIC
MEANS
ANCIENT LIFE
CENOZOIC
AGE of
MAMMALS
MESOZOIC
AGE of
REPTILES
PALEOZOIC
MARINE LIFE
EXPLODES
Why do the
eras in time
end?
What can cause
MASS EXTINCTION …
 What evidence is found
in Earth’s rocks to
explain the Permian
mass extinction about
250 million years ago?
http://www.pbs.org/wgbh/nova/sciencenow/3318/01.html
Climate Change can cause
MASS EXTINCTION …
What evidence is found in Earth’s rocks to explain the
Permian mass extinction about 250 mya?



Use the resources on the table and your
reference table to identify 2 different fossils
you choose. They are from NYS so they are
from the Paleozoic era (mostly Devonian and
Silurian)
Use your ESRT to estimate the period in which
they lived and their possible age.
Draw them in your notebook. Make notes
about the organism name (Genus species),
time period, and age.
What can we learn about Earth’s
history from salt deposits?
FIND LINK
ON
WEBSITE!
Nova Science
NOW:
Secrets in
the Salt
How to use
scale model to
find time
boundaries
between
eons
How to use
scale model to
find time
boundaries
between
eras & periods
How to use
scale model to
find time
boundaries
between
epochs
How would you calculate…
During what percent of
Earth’s history have
forests existed?
First Forests during the
mid-Devonian, half way
between 416-359 mya
This was about 380 mya
380 my  about 8% of
4600 my
Earth’s history
 Remember to plot Table 2 first (time periods) and then
plot events from Table 1
 Each lab partner needs to calulate age of 4 fossils and
then draw and label 2 on the time line
 When you are satisfied with your time “lines,” Go over
them in in marker (see me) so we can compare all of
them tomorrow!
Both lab partners get same grade so make sure you
work together and turn it in on time!