1. Paleozoic Era Life starts in the seas and moves onto land
570,000,000 years ago to 225,000,000 years ago
Six periods:
Cambrian
Ordovician
Silurian
Devonian
Carboniferous
Permian

3. Cambrian Period (570-500 MYA)
Cambrian Explosion – Most major animal phyla are found in the fossil record (mostly aquatic invertebrates with exoskeletons).
Burgess Shale – major fossil site located in Canadian Rockies

5. Ordovician Period (500-435 MYA)
1st vertebrates - jawless fish (filter feeders)
The vertebrate protects the spinal cord, which carries signals from the brain throughout the body.
The lamprey of today is a parasite.
The hagfish is a scavenger.

7. Silurian Period (435-395 MYA)
1st jawed fish (later evolved into sharks-made of cartilage).
Ozone (O3) layer formed which blocks harmful UV radiation; life could evolve on land.
1st land plants (mosses & ferns) followed by 1st land animals (arthropods-spiders & scorpions).

9. Devonian Period (395-345 MYA)
“Age of the Fish” (giant armored fish).
1st bony fish (scales and swim bladder for buoyancy).

10. Devonian Period (395-345 MYA)
1st vertebrates on land – amphibians
Evolved from the lobed-fin fish which include some species of lungfish.

12. Carboniferous Period (345-280 MYA)
North America is at the equator (tropical swamps form coal deposits)
Amphibians & insects dominate and become large
(dragon flies-1m wing span; cockroaches-10 cm long).
1st reptiles

14. Permian Period (280-225 MYA) Reptiles dominate.
Pangaea begins to form (Appalachian Mnts; dry climate; ice age in the southern hemisphere)
Mass Extinction (90% of all species go extinct-mostly marine invertebrates).
Early Permian reptiles, Cacops in front & Casea in back.
The middle Permian reptile, Anteosaurus.

15. Mass Extinction
One of the Big FIVE Mass Extinctions