Paleozoic Era

Paleozoic Era

Ordovician Period

Permian Period

Silurian Period

Cambrian Period

Carboniferous Period

541 to 251.9 Million Years Ago (MYA)

Devonian Period

Trilobite

Placoderm

Gorgonopsid

Resources

• First true fish appear - Ostracoderms

• Growth of plant life on land
• Took so much CO2 out of the air that temperatures plummeted into an ice age
• This caused oxygen levels to drop and cause the Ordovician-Silurian Extinction Event, whiping out 86% of marine life

Sequel to Cambrian Explosion

aka GOBE (485.4 to 443.8 MYA)

Great Ordovician Biodiverification Event

• Phytoplankton using photosynthesis made oxygen levels rise
• Rise of Corals, Trilobites, and Primitive Fish
• Ended due to a crash in oxygen levels that caused the Cambrian-Ordovician Extinction Event

• This event caused a lot of trilobites and mollusk species to die off

Important notes:

The start of complex life (541 to 485.4 MYA)

Cambrian Explosion

• Ostracoderms evolved to have protective "headgear" to avoid being attacked by predators
• Jawed fish evolved to eat what the jawless fish could not
• The extinction event saw many bottom dwellers, such as cephalopods, die out

Life Continues to Evolve (443.8 to 419.2 MYA)

• Amniotes evolved to combat conditions
• ended in catastrophe known as Permian-Triassic Extinction Event
• 96% of marine life lost, including all trilobites
• 70% of terrestrial species lost

Temperature became even more hostile for the animals

"Everything is huge! Including bugs!" - bill wurtz

Amniotes' world, until it wasn't (298.9 to 251.9 MYA)

• Late devonian extinctions characterized by drop in oxygen levels
• Brought an end to the Devonian Period

Animal life on land grows as insects and the first amphibians learned to walk and live on land

Main new fish - Placoderm - an early shark or whale

Fish take over (419.2 to 358.9 MYA)

• Due to Pangea's massive size, it is hard for ocean water to reach inland
• Because of this, Carboniferous Rainforests Collapsed and were replaced with a giant desert in the middle of the supercontinent
• However, amniotes were able to inhabit this area and split into 2 groups the reptiles and the synapsids

Slowly continents formed Pangea

Insects grew to be huge due to the dense rainforests in this period

Animals learn to use an egg on land (358.9 to 298.9 MYA)