1. Geologic Time Scale- 10/18/11
Bell Ringer-
How old do you think the Earth is, according to
geologists?
2. How old do you think life is, according to
geologists?
3. What is the law of superposition? What does
this law say?

2. Geologic Time Scale- 10/18/11
Make a timeline of your life
Include At least 5 major
(important) events

3. THE EARTH IS POWERFUL
• As you watch this, imagine you are inside this
building in Japan.
– How would it feel to be there?
http://www.youtube.com/watch?v=pytPBwY0Sw8&
feature=BFa&list=PL3F819A227D58B74F&lf=result
s_main

4. THE EARTH IS OLD
• Each table has a list of @’s on it.
• 2,000 @ signs on this paper,
50 per row.
• Starting at the top left, label as many @ signs as
you can with events of the past 2,000 years in 5
minutes:
• Your birthday
• Your parent’s/grandparents’ birth years
• Historical years you remember (1969, 1945, 1776, etc.)

5. Examples: Important Dates
• 1969- Moon Landing
• 1955- Polio Vaccine
• 1945- end of WWII
• 1912- Titanic Sinks
• 1860- Start of Civil War
• 1674- Bacteria are first seen by people
• 476- Roman Empire Collapses

6. THE EARTH IS 4.6 BILLION years
old!
• How many reams of paper would you need, full
of “@” signs, to count up 4.6 billion years??

7. FIND OUT HOW GEOLOGIC TIME LOOKS…
in paper!
Event # of Years Reams or Sheets
Ago of Paper
Last ice age ended. 10,000
All dinosaurs are extinct 65 million
Appalachian Mountains 460 million
formed.
Algae developed. 1 billion
Unicellular organisms 3.5 billion
appeared.
Earth formed. 4.6 billion

8. Testable Question
• What is an extinction? What are the major
causes of causes of extinctions?

9. Research/Background Info
• Extinction: when a species (plant or animal)
disappears from Earth;
– 99.9% of all species that have ever lived are
now extinct!
• Mass extinction: large numbers of species
die out in a short time
• Almost all extinctions are caused by
environmental change

10. THE EARTH IS POWERFUL
• As you watch this, imagine you are inside this
building in Chile.
– How would it feel to be there?
http://www.youtube.com/watch?v=MqkQbAAYsnI&
feature=related

11. Data Collection/Analysis
• Create a picture for each of the 8
natural causes of species
extinctions in your notebook

12. Data Collection/Analysis
• Natural events that cause extinctions:
– Increase/decrease in temperature
– Increase/decrease in rainfall
– Volcanic eruption
– Earthquake
– Flooding/drought
– Shifting land or sea
– Change in food supply
– New predator or disease

13. Data Analysis
Write Time! (In your notebook, write at least 3
sentences)
• What cause(s) do you think is responsible for
the extinction of the dinosaurs?
• What is the cause of all natural species
extinctions (including the dinosaurs)?

14. Experiment
• Extinction of the
Dinosaurs! Video
clip
• http://www.yout
ube.com/watch?v
=y4COsg8o02Q&f
eature=watch_res
ponse_rev

15. Testable Question
• What is the Geologic Time Scale?
How is it organized?

16. Research/Background Information
• Geologic Time Scale: timeline that
organizes the events in Earth’s history
• Today's Calendar:
– Year, Month, Week, Day
• Geologic Time Scale:
– Eon, Era, Period, Epoch
• Separated by major events: Mass
extinctions, development of many new
species…

17. THE GEOLOGIC TIME SCALE
• The Geologic Time Scale is the calendar of
Earth’s history, organized by important events
(extinctions, development of life).
• We are going to draw one!
• DRAW A LONG LINE ACROSS YOUR PAGE

18. THE GEOLOGIC TIME SCALE
• In a timeline, we put the oldest date on the
left and the newest on the right.
• The GTS starts at 4.6 bya (billion years ago)
• ADD “4.6bya- Earth forms” to your timeline

19. THE GEOLOGIC TIME SCALE
• At about 4bya, prokaryotes (bacteria!) appear in
oceans.
• ADD “4.0 bya- First prokaryotes” to your timeline

20. THE GEOLOGIC TIME SCALE
• For 4 billions years, life was too small and soft to
make fossils.
• This time of little fossils from 4.6bya-542 mya is
the Precambrian.
ADD “PRECAMBRIAN” above your timeline, until 542
mya PRECAMBRIAN

21. THE GEOLOGIC TIME SCALE
• The Paleozoic Era was when fish, forests, and
reptiles appeared (542mya-251mya)
PRECAMBRIAN Paleozoic Era

22. THE GEOLOGIC TIME SCALE
• The Mesozoic Era was when dinosaurs appeared
(251mya-65 mya)
PRECAMBRIAN Paleozoic Mesozoic

23. THE GEOLOGIC TIME SCALE
• The Cenozoic Era was when mammals thrived.
• Humans appeared about 500,000 years ago.
Mesozoic
PRECAMBRIAN Cenozo
Paleozoic

24. Analysis:
• When you tell someone that something
happened a long time ago, how does your
version of a long time ago compare to the Earth’s
geologic time?
• How does the time humans have spent on Earth
compare to geologic time as a whole?
• Have we been here a long portion of geologic
time or only a small period of time? Justify your
answer.

25. Exit TickET EOG Question
• The geologic time scale is divided by major
changes or events such as:
A.mass extinctions
B.the development of one new species
C.the extinction of one species
D.a small temperature change

26. Experiment
• In what Period did the first
dinosaurs appear?

27. Review
• How do scientists divide Earth's
History on the GTS?

28. Review
• During what Period did the first
insects appear?

29. Review
• In what Epoch do we live in?

30. Review
• List the Eras in order from most
recent to oldest.

31. Experiment
• In what Epoch did mammals
become abundant?

32. Experiment
• What type of organisms first lived
on Earth?

33. Experiment
• In what Period could you first pick
a bouquet of flowers?

34. Experiment
• How many years ago did the first
fish live on Earth?

35. Review
• What happened 360 million years
ago?

36. Review
• During what Eon did multi-
cellular organisms evolve?

37. Review
• In what period did the first
insects live?

38. Review
• How many years ago did the first
amphibian live on Earth?