Summary of Life from Paleozoic to Cenozoic

Arthropods

Eurypterids and Trilobites (become extinct)
Insects, etc.

Brachiopods

Abundant, decline at end of Paleozoic

Echinoderms

Commonly stemmed (blastoids, crinoids), now mostly extinct

Mollusca

Ammonites
Gastropods and Bivalves not especially important

Other groups, not placed in phyla

Graptolites
Conodonts
Archaeocyathids (formed reefs)
Fusilinids (formed reefs)
All of the above are now extinct

Permian extinctions (80% of species)

Corals
Bryozoans
Brachiopods
Crinoids
Trilobites

Triassic extinctions

Conodonts
More coral groups

The survivors diversify in the Jurassic and Cretaceous:

Clams, particularly oyster-types

Inoceramus (index fossil for the Jurassic)
Gryphaea
Rudistids

Ammonites
Belemnites

Cretaceous extinctions

Ammonites
Belemnites
Major microrganism groups
Large reptiles of nearly every type, in air, water or on land

New on the scene in Cretaceous

Flowers (Angiosperms)
Diatoms

Useful links:

Earth Science Picture of the Day

Return to Historical Geology syllabus