1. What did this organism do?
Journal #55
What was the most predominant life-form that existed during the Precambrian Era?
What did this organism do?
What are the 6 periods of the Paleozoic Era?

2. Today we will identify major geologic and biological developments during the Mesozoic and Cenozoic Eras

3. End of the Paleozoic Era
At the end of Paleozoic Era 90% of marine organisms and 70% of land organisms died.
This episode when large numbers of organisms become extinct is known as a mass extinction
This extinction happened because there were many new life-forms that appeared.

4. Mesozoic Era
Earth’s surface changed dramatically during the Mesozoic Era.
Pangaea broke into smaller continents and the tectonic plates drifted and collided.
Creating mountains and shallow seas
Conditions of the Mesozoic Era favored reptiles.
Age of the Reptiles (Era)
What are some examples of reptiles?

5. Mesozoic Era
Earth’s surface changed dramatically during the Mesozoic Era.
Pangaea broke into smaller continents and the tectonic plates drifted and collided.
Creating mountains and shallow seas
Conditions of the Mesozoic Era favored reptiles.
Age of the Reptiles (Era)
What are some examples of reptiles?
Divided into 3 periods

6. Triassic Period Dinosaurs appeared
Some were as small as squirrels and others were 30m long
Most were 4-5m long
New forms of marine invertebrates also evolved

7. Jurassic Period Dinosaurs became the dominant life- form
2 major groups of dinosaurs
Saurishians (lizard hipped)
Herbivores (brontosaurus)
Carnivores
Ornithischians (bird-hipped)
Hervivores (stegosaurus)

8. Cretaceous Period Dinosaurs continued to dominate the Earth
Tyrannosuarus rex
Harosuars
Ankylosuars
Plant life became very sophisticated
Flowering plants appeared
Trees became abundant
Maple
Oak
walnut

9. Mass Extinction The Cretaceous Period ended in another mass extinction
Environmental changes may have caused this extinction (such as tectonic activity/volcanic activity)
Impact hypothesis- giant meteorite crashed into Earth and raised enough dust to block the suns rays for many years. (Iridium is evidence)

10. Review What are the 3 periods of the Mesozoic Era?
What Period did dinosaurs first appear?
When did flowering plants first appear?
What event marked the end of the Mesozoic Era?

11. Cenozoic Era Includes the present period
Continents moved to their present day positions
Movement of the tectonic plates formed mountains such as:
Alps
Himalayas
Dramatic climate changes occurred
At times, ice sheets covered 1/3 of land
Temperatures decreased and new species adapted
“Age of the mammals”

12. Cenozoic Era is divided into Epochs
2 periods:
Tertiary
Time before the last ice age
Quaternary
Began with the last ice age and includes present
Cenozoic Era is divided into Epochs

13. Cenozoic Era is divided into Epochs
2 periods:
Tertiary
Time before the last ice age
Quaternary
Began with the last ice age and includes present
Cenozoic Era is divided into Epochs

14. Your Assignment: Complete the graphic organizer
Describe the environment of each period and identify at least one life form that existed during that time.