1. So, how has the Earth & LIFE changed over its 4
So, how has the Earth & LIFE changed over its 4.6 billion years existence?

2. This is known as our GEOLOGIC
TIME SCALE

3. WORK WITH YOUR SEAT PARTNER
Let’s make a GEOLOGIC TIME SCALE on a strip of paper like the paper towel one I have on my wall.
WORK WITH YOUR SEAT PARTNER

4. MAKE YOUR STRIP 46 inches long!

5. MAKE YOUR STRIP 46 inches long!
(46 inches = 4.6 BILLION yrs)

6. COLOR the 1st 7 inches light red

7. The sun, earth and moon were forming.

8. It’s called “HADEAN”era…like Hades.

9. That’s because our Earth was a volcanic fireball for its first
It’s called “HADEAN”…like Hades.
That’s because our
Earth was a volcanic
fireball for its first
0.7 billion years!

10. The next 16 inches shade BLUE

11. 3.8bya-2.5bya Unicellular prokaryotes thrive
That’s because the next 1.6
billion years the Earth got
covered in OCEAN!
Archean Era:
3.8bya-2.5bya Unicellular prokaryotes thrive

12. The next 16 inches shade BLUE
Draw a bacteria here!
The next 16 inches shade BLUE

13. 3.8bya-2.5bya Unicellular prokaryotes thrive
During this time, LIFE BEGAN
as PROKARYOTIC BACTERIA
in this WATER!
Archean Era:
3.8bya-2.5bya Unicellular prokaryotes thrive

14. the next 17 inches shade in GREEN

15. The next 17 inches shade in GREEN.
You should have 6” left.

17. complex unicellular eukaryotes grew
Proterozoic Era:
2.5bya—540mya
complex unicellular eukaryotes grew

18. complex unicellular eukaryotes grew
This 17 inches represents
the 1.7 billion years that
cyanobacteria were
photosynthesizing in the
waters on Earth.
Proterozoic Era:
2.5bya—540mya
complex unicellular eukaryotes grew

19. complex unicellular eukaryotes grew
Photosynthesis begins with
phytoplankton! It gives Earth
what important gas for life?
Proterozoic Era:
2.5bya—540mya
complex unicellular eukaryotes grew

20. OXYGEN is being produced by cyanobacteria / algae / phytoplankton

21. this ENTIRE FIRST 4 BILLION YEARS on Earth is called PRECAMBRIAN
(only what existed?)

22. the ENTIRE FIRST 4 BILLION YEARS on Earth is called PRECAMBRIAN (only microbes exist)

23. PRECAMBRIAN EON

24. PRECAMBRIAN EON (era) was IMPORTANT for LIFE on Earth!
FIRST 4.0 BILLION YEARS OF EARTH HISTORY
SUN, EARTH, then MOON formed,
OCEANS formed
LIFE began simply (one cell at-a-time).
Our ATMOSPHERE was created through volcanoes & from photosynthesizing bacteria (algae, phytoplankton) making OXYGEN,

25. Only the last 600 million years complex life has evolved

26. Let’s zoom into this .6 billion years!

27. We’ve only had complex life only recently on Earth…this last
We’ve only had complex life only recently on Earth…this last .6 billion years.

28. Mark 3. 5 inches (. 35 billion yrs
Mark 3.5 inches (.35 billion yrs.) as PALEOZOIC (plants, bugs, & fishes

29. Of this last 6 inches of our GEOLOGIC TIME SCALE, 3
Of this last 6 inches of our GEOLOGIC TIME SCALE, 3.5 inches are the PALEOZOIC era or 350 million years of fishes, plants and bugs.

30. …

31. Mark 2 in. (.2 billion yrs.) as MESOZOIC (amphibiansreptiles, dinosaurs ruled)

32. Dinosaurs ruled!

33. The last .65 inch (65,000,000 years) flowers and MAMMALS thrived during the CENOZOIC ERA!

34. The LAST 65 million years, we MAMMALS thrive during our CENOZOIC era!

35. The LAST 65 million years, we MAMMALS thrive during our CENOZOIC era!
.65 inch = 65,000,000 YEARS!!

36. PRECAMBRIAN EON
COMPLEX
LIFE HERE

37. PRECAMBRIAN EON
COMPLEX
LIFE HERE
GEOLOGIC TIME SCALE

38. MAJOR EXTINCTION EVENTS!
PRECAMBRIAN EON
COMPLEX
LIFE HERE
GEOLOGIC TIME SCALE
broken up into
MAJOR EXTINCTION EVENTS!

39. MAJOR EXTINCTION EVENTS!
PRECAMBRIAN EON
COMPLEX
LIFE HERE
GEOLOGIC TIME SCALE
broken up into
MAJOR EXTINCTION EVENTS!

40. See how we’ve only had complex life only recently on Earth.

41. See how we’ve only had complex life only recently on Earth.

42. See how we’ve only had complex life only recently on Earth.
LIFE had to START OVER
at EACH of these ERAS!