Earth HistoryEarth History

The Paleozoic EraThe Paleozoic Era

Paleozoic TimePaleozoic Time(544 - 245 Million Years Ago)(544 - 245 Million Years Ago)

Bracketed by the two most Bracketed by the two most important biological events in important biological events in Earth’s history:Earth’s history:

1.1. The first appearance of The first appearance of complex organismscomplex organisms

2.2. The largest mass extinction on The largest mass extinction on the history of the Earth. the history of the Earth.

Paleozoic TimePaleozoic Time There are 7 subdivisions (periods) There are 7 subdivisions (periods)

in the Paleozoicin the Paleozoic– Cambrian (Cambrian (oldestoldest))– OrdovicianOrdovician– SilurianSilurian– DevonianDevonian– Carboniferous (Mississippian and Carboniferous (Mississippian and

Pennsylvanian)Pennsylvanian)– Permian (Permian (most recentmost recent))

Cambrian Cambrian (544 - 490 million years ago)(544 - 490 million years ago)

During the Cambrian period, most During the Cambrian period, most of the major groups of organisms of the major groups of organisms alive today first appeared. alive today first appeared.

The appearance of organisms was The appearance of organisms was VERYVERY rapid. rapid.– The “Cambrian Explosion”The “Cambrian Explosion”– A 5 – 10 million year period of A 5 – 10 million year period of

rapid evolutionary development.rapid evolutionary development.

The Cambrian SeafloorThe Cambrian Seafloor

The Cambrian SeafloorThe Cambrian Seafloor

Cambrian FossilsCambrian FossilsTrilobitesTrilobites

Elrathia

Peronopsis

PtychagnostusBathyuriscus

Brachyaspidon

Cambrian FossilsCambrian FossilsBrachiopods and EchinodermsBrachiopods and Echinoderms

Starfish

Starfish

Sand Dollar

Brachiopods

Unique FossilsUnique Fossils

The Burgess Shale (Alberta, The Burgess Shale (Alberta, Canada) contains very unique Canada) contains very unique middle Cambrian fossils. middle Cambrian fossils.

These animals displayed These animals displayed rapidrapid diversificationdiversification and and existed for only a short period existed for only a short period before they became extinct.before they became extinct. Charles

DolittleWalcott

Burgess Shale, CanadaBurgess Shale, Canada

Burgess Shale FossilsBurgess Shale Fossils

WiwaxiaWiwaxia

AnomalocarisAnomalocaris

MarrellaMarrella

Burgess Shale FossilsBurgess Shale Fossils

OttoiaOttoia

LeanchoiliaLeanchoilia

OrdovicianOrdovician(490 - 443 million years ago)(490 - 443 million years ago)

Most animals alive in the Most animals alive in the Ordovician were similar to those Ordovician were similar to those alive in the Cambrian. alive in the Cambrian.

Introduction of animals similar to Introduction of animals similar to squid.squid.– CephalopodsCephalopods

The Ordovician Sea FloorThe Ordovician Sea Floor

Ordovician FossilsOrdovician FossilsCephalopods (Squids)Cephalopods (Squids)

Ordovician FossilsOrdovician FossilsBrachiopodsBrachiopods

Ordovician ExtinctionOrdovician Extinction

The Earth’s climate became much The Earth’s climate became much cooler in the middle Ordovician.cooler in the middle Ordovician.– Glaciers covered much of the continentsGlaciers covered much of the continents– Sea level droppedSea level dropped

Climate change, probably, was Climate change, probably, was responsible for the Ordovician mass responsible for the Ordovician mass extinction.extinction.

60% of marine organisms60% of marine organisms

SilurianSilurian(443 - 417 million years ago)(443 - 417 million years ago)

The Earth’s climate became stable The Earth’s climate became stable and a bit warmer during the and a bit warmer during the Silurian. Silurian.

This allowed manyThis allowed many new animals new animals to to appear for the first time. appear for the first time. – Coral ReefsCoral Reefs– First (Jawless) FishFirst (Jawless) Fish– Land plantsLand plants

Silurian Coral ReefsSilurian Coral Reefs

What is coral? An invertebrate animal What is coral? An invertebrate animal related to jellyfish.related to jellyfish.

Small marine animals that live in warm Small marine animals that live in warm water.water.

They make a “skeleton” out of calcium They make a “skeleton” out of calcium carbonate and often live in large colonies carbonate and often live in large colonies (reefs)(reefs)

Silurian CoralSilurian Coral

Horn CoralHorn Coral– Horn shapedHorn shaped– Usually lived alone; Usually lived alone;

non-reefnon-reef forming forming– ExtinctExtinct

Pipe CoralPipe Coral– Honey-comb shapeHoney-comb shape– Often formed reefsOften formed reefs– ExtinctExtinct

Silurian Fish Silurian Fish (Ostracoderm)(Ostracoderm) VertebratesVertebrates Thought to be Thought to be

related to fish related to fish with jaws and with jaws and sharks.sharks.

Ate through a Ate through a ‘sucker’ mouth.‘sucker’ mouth.

EurypteridsEurypterids Extinct group of Extinct group of

marine marine organisms.organisms.

Feeding Feeding appendages in appendages in the front.the front.

Related to Related to modern spiders modern spiders and scorpions. and scorpions.

NYS State Fossil NYS State Fossil

Silurian Silurian PlantsPlants

Lived near shorelines and in shallow waters

Slowly ‘invaded’ the land area by spreading in from rivers and lakesCooksonia

DevonianDevonian(417 - 345 million years ago)(417 - 345 million years ago)

The first appearances of real “trees”The first appearances of real “trees”– Most vegetation was small plantsMost vegetation was small plants– Tallest plants were only about 3 feet tallTallest plants were only about 3 feet tall

First amphibiansFirst amphibians First wingless insectsFirst wingless insects

Marine life continuedMarine life continued– Brachiopods, coral, echinoderms, and Brachiopods, coral, echinoderms, and

new fishnew fish

Devonian OrganismsDevonian Organisms

Tree Fossil Cockroach & Tarantulasimilar to Devonian

Arthropods

Early AmphibianFossil

Devonian TreesDevonian Trees

Most were shorter than Most were shorter than 1 meter tall.1 meter tall.

Ferns, horse tails, and Ferns, horse tails, and seed plants were seed plants were common.common.

The first forests were The first forests were present.present.

Devonian Insects Devonian Insects (Arthropods)(Arthropods)

Arthropods are Arthropods are the most the most successful type of successful type of animal on the animal on the planet.planet.

6 - 9 million 6 - 9 million species in a species in a typical forest typical forest today.today.

Not Devonianfossils

CarboniferousCarboniferous(354 - 290 million years ago)(354 - 290 million years ago)

Subdivided into the Mississippian Subdivided into the Mississippian and Pennsylvanian.and Pennsylvanian.

Lots of swamps and coal Lots of swamps and coal formation.formation.

First reptiles.First reptiles.– Major biological revolution - Major biological revolution - the hard the hard

shelled egg!shelled egg!

A Carboniferous ForrestA Carboniferous Forrest

Carboniferous Plant FossilsCarboniferous Plant Fossils

Carboniferous Reptile Carboniferous Reptile FossilsFossils

Reptiles can live on Reptiles can live on land or in water, BUT...land or in water, BUT...

Amniotic eggAmniotic egg - has a - has a shell that allows shell that allows animals to reproduce animals to reproduce on land. on land.

Allows reptiles to move Allows reptiles to move further onto land, away further onto land, away from water.from water.

PermianPermian(290 - 245 million years ago)(290 - 245 million years ago)

Last period of the PaleozoicLast period of the Paleozoic Ends with the largest mass Ends with the largest mass

extinction in the history of the extinction in the history of the planetplanet– Mostly affected the animals in the Mostly affected the animals in the

oceansoceans

Permian Reptile FossilsPermian Reptile Fossils

DimetrodonDimetrodon

Permian ReptilesPermian Reptiles

DimetrodonDimetrodon

LeanchoiliaLeanchoilia

End of the PaleozoicEnd of the Paleozoic

Largest mass extinction in Earth’s Largest mass extinction in Earth’s historyhistory– 90% - 95% of all marine species 90% - 95% of all marine species

became extinctbecame extinct– Likely due to changes in the Likely due to changes in the

environment and competition for living environment and competition for living space.space.

– Colder climate =Colder climate =– Volcanic eruptions = Volcanic eruptions =