1. Chapter 14: Geologic Time
Table of Contents
Chapter 14: Geologic Time
Section 14.1: Life and Geologic Time

2. Life and Geologic Time 1

3. Plate Tectonics and Earth History
Life and Geologic Time 1
Plate Tectonics and Earth History
(1) Plate tectonics can cause landmasses to move from one climate zone to another. This will affect the environments available for lifeforms.

4. Early Earth History 2
Precambrian Time

5. Precambrian Time 2 Oldest rocks found are (3) 4 billion years old
Early Earth History 2
Precambrian Time
Oldest rocks found are (3) 4 billion years old
Rocks older than 3.5 billion years are rare because (4) they have been re-melted and eroded away.

6. Early Earth History 2
Precambrian Time
Fossils record is rare (5) because the organisms had no hard parts and have been destroyed over time.

7. Early Earth History 2
Early Life
(6) Stromatolites are layered mats formed by cyanobacteria colonies. Oldest know fossils on earth.

8. Early Life 2 (7a) cyanobacteria added oxygen to the air
Early Earth History 2
Early Life
(7a) cyanobacteria added oxygen to the air
(7b) ozone developed in the atmosphere

9. Early Earth History 2
Early Life
(8) Animals without backbones, called invertebrates, appeared toward the (9) end of Precambrian time.
Because these early (10) invertebrates were soft-bodied, they weren’t often preserved as fossils.

10. (11) The Paleozoic Era 2 abundance of organisms with hard parts,
Early Earth History 2
(11) The Paleozoic Era
abundance of organisms with hard parts,
Animals with backbones called vertebrates developed
most animal life was in the ocean
Warm, shallow seas covered much of the earth

11. Paleozoic continued 2 Appalachian Mountains formed
Early Earth History 2
Paleozoic continued
Appalachian Mountains formed
when the African Plate collided with the North American Plate.

12. End of the Paleozoic Era
Early Earth History 2
End of the Paleozoic Era
At the end of the Paleozoic Era, more than 90 percent of all life died off.
plates came together and formed the supercontinent Pangaea.
climate became cooler and drier.

13. (13) The Mesozoic Era 3 Reptiles, specifically dinosaurs appeared
Middle and Recent Earth History 3
(13) The Mesozoic Era
Reptiles, specifically dinosaurs appeared
Pangaea separated into two large landmasses.
Birds and Mammals developed

14. Middle and Recent Earth History3
End of an Era
Many paleontologists hypothesize that a (14) comet or asteroid collided with Earth, causing a huge cloud of dust and smoke to rise in the atmosphere, blocking out the Sun.

15. Middle and Recent Earth History3
(15) The Cenozoic Era
Many mountain ranges in North and South America and Europe formed
Climate became cooler and ice ages occurred early in the era.
Continents moved to their current positions