PALEOZOIC ERA

ABUNDANT FOSSILS BEGIN

START of the PALEOZOIC ERA

• Continents separate

• North American continent at the equator with the Arctic region facing eastward

PALEOZOIC PERIODS

Cambrian

Ordovician

Silurian

Devonian

Mississippian

Pennsylvanian

Permian

• Trilobites, 1st vertebrates

• Graptolites, 1st corals

• Eurypterids, 1st land animals

• Age of fishes, 1st forests

• Crinoids & Foraminifera

• Age of Cockroaches, 1st reptiles

• Pangaea forms, 1st mammals

CAMBRIAN PERIOD

• No land plants or animals

• Most of North America covered with warm oceans

• Burgess Shale forms in the Rocky Mountain region with soft bodied animals

• Common fossils– Trilobites (like crabs) - index

– Brachiopods (like clams)

– Ostracoderms (primitive fish)

Cambrian Period – Life in the Oceans

Fossil Found in the Burgess Shale

Trilobite – Index Fossil of the Cambrian Period

ORDOVICIAN PERIOD

• All life exists in the oceans

• Small plate from northwest Africa collides with eastern North America to form the Green & Taconic mountains

• Common fossils

– Graptolites (colonial floating animals) - index

– Brachiopods, bryozoans, pelecypods, corals,

echinoderms, gastropods, cephalopods

Ordovician Period – Life in the Oceans

Graptolite – Index Fossil of the

Ordovician Period

SILURIAN PERIOD

• 1st land animals– Ancestors of spiders, millipedes, scorpions

• Land plants– Club mosses

• Eastern North America– Dry climate evaporates the shallow seas leaving large

salt & gypsum deposits

• Common fossils– Eurypterids (sea scorpions) – index

– Coral forming coral reefs, others like Ordovician life

Eurypterid –

Index Fossil

of the Silurian

Period (a sea

scorpion)

DEVONIAN PERIOD

• Age of Fishes– Lungfish lived briefly on land

• 1st forests– Primitive conifers, ferns, giant rushes

• North America– Still at the equator, northwest Africa collides with

eastern North America to form the northern Appalachians & White mountains

• Common fossils– Coral reefs, jawless & armoured fish

Age of

Fishes

Marine Life of the Devonian Period

Formation of the Northern Appalachian Mountains

Flooding of the Land – Fertile Soil for Plants

Trees Taking Root on Land to Form

the 1st Forests

Trees of the Devonian Period

Extinctions of the Devonian Period

MISSISSIPPIAN PERIOD

• Common fossils

– Crinoids (sea lilies) – starfish attached to the

sea floor

– Foraminifera (amoeba like single celled

animals) – tiny calcite shells

• North America

– Southern Appalachian mountains form

Crinoid

Attached to the sea floor

Foraminifera

Single-celled

Calcite shells

Animals of the Mississippian Period

North America at the Equator

– Forming the Southern Appalachian Mountains

PENNSYLVANIAN PERIOD

• Age of Cockroaches

– Insects increase, large dragonflies & cockroaches

• 1st reptiles

– lizards

• North America

– Still at the equator

– Warm, wet climate floods eastern USA in huge

freshwater swamps – forming rich coalfields

– Continents continue colliding to form the Appalachian

mountains

Age of the Cockroaches

Swamps Covering Eastern North America – forming coalfields

1st Reptiles

– the Lizards

North America at the Equator

– forming the Appalachian Mountains

PERMIAN PERIOD

• Dry climate

– Shallow inland seas evaporated leaving large

deposits of salt & gypsum

• Large reefs

– Coral, algae, sponges thrived

• Great southern ice age

– South America, Australia, South Africa, India

Dry Climate of the Permian Period

- Shallow inland seas

Large Coral Reefs

Large Reptiles of the Permian Period

END of the PALEOZOIC ERA

• Pangaea forms– Continental crust welds together into one

supercontinent

• Mountains form– Appalachian & Ural mountains fully elevate

• 96% species extinction– Trilobites, eurypterids, coal forming seed ferns, scale

trees & primitive conifers - extinct

• 2 important survivors– Cephalopods (oceans) & reptiles (land)

Pangaea

– the Supercontinent