Paleozoic (542-251 mya) events

Paleozoic (542-251 mya) events

Late Paleozoic-key thingsLate Paleozoic-key things･･ Several key things happen beginning atSeveral key things happen beginning at

the end of the Silurian through the Permianthe end of the Silurian through the Permian- - Assembly of Pangaea (also spelled Pangea)Assembly of Pangaea (also spelled Pangea)

> > rearranges amounts of shallow marine habitatsrearranges amounts of shallow marine habitats> > rearranges climate of the worldrearranges climate of the world> > organisms are becoming more diverseorganisms are becoming more diverse> > more families of organisms appearingmore families of organisms appearing

- - Development of ChordatesDevelopment of Chordates> > probably in repsonse to increasing competitionprobably in repsonse to increasing competition> > includes many common animals includes many common animals

- - Development of land plantsDevelopment of land plants> >

PangaeaPangaea･･ assembled by the early Permianassembled by the early Permian･･ as it comes togetheras it comes together

- - shallow epicontinental seas diminish in sizeshallow epicontinental seas diminish in size> > periodic- i.e., still fluctuating but getting smallerperiodic- i.e., still fluctuating but getting smaller

- - Mountains are sources of sediment to the east Mountains are sources of sediment to the east and west in USand west in US

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Devonian world- tectonic & paleogeographic setting Devonian world- tectonic & paleogeographic setting



Devonian Paleogeography of N. America



Carboniferous (Pennsylvanian) world- tectonic and paleogeographic setting

Carboniferous (Pennsylvanian) world- tectonic and paleogeographic setting





Permian world- tectonic & paleogeographic setting

Permian world- tectonic & paleogeographic setting





Schematic CyclothemSchematic Cyclothem



Colonizing land• plants were the first things to colonizethe land

• late Silurian- two big categories of plants

> Tracheophytes or vascular plants (trees, ferns, andother plants with tissues that could transportnutrients)

> Chlorophytes or green algae > these were probably around since the Ordovician butadapted to fresh water settings

Colonizing land• plants were the first things to colonizethe land

• late Silurian- two big categories of plants

> Tracheophytes or vascular plants (trees, ferns, andother plants with tissues that could transportnutrients)

> Chlorophytes or green algae > these were probably around since the Ordovician butadapted to fresh water settings

Factors for plants to overcome• moisture

- adapt to freshwater- adapt to move from saturated ground

• stablility- not true wood producing plants

> e.g., ferns and plants that have little in the way ofwoody vascular tissues

• nutrients- root systems needed to develop

• reproduction- early plants used spores (seedless) means

• Explains why they took so long to colonize

Factors for plants to overcome• moisture

- adapt to freshwater- adapt to move from saturated ground

• stablility- not true wood producing plants

> e.g., ferns and plants that have little in the way ofwoody vascular tissues

• nutrients- root systems needed to develop

• reproduction- early plants used spores (seedless) means

• Explains why they took so long to colonize

Coal forests in Pennsylvanian andCoal forests in Pennsylvanian andMississippianMississippian

• • evidence suggests they did not stray too farevidence suggests they did not stray too farfrom water sourcesfrom water sources

- - few plants in upland areasfew plants in upland areas

• • Plant species like Plant species like LepidodendronLepidodendron (a family of (a family ofplants known as a Lycopsids)plants known as a Lycopsids)

- - got really huge in the late Carboniferousgot really huge in the late Carboniferous

• • Sphenopsids (spine-like rushes and horsetailSphenopsids (spine-like rushes and horsetailplants)plants)

- - smaller than Lycopsidssmaller than Lycopsids

• • Both reproduce by means of spores asBoth reproduce by means of spores asopposed to seedsopposed to seeds

Ferns and tree ferns･ also around beginning in late Devonian

- haven't changed much in 370 million years

･ wide variety of sizes- some were small- some were as big as the biggest trees today

Seed bearing plantsSeed bearing plants• • "seed ferns" were the first plants to"seed ferns" were the first plants toproduce true seedsproduce true seeds

- - unlike real ferns that produce spores forunlike real ferns that produce spores forreproductionreproduction

• • occurs in late Pennsylvanianoccurs in late Pennsylvanian• • Offers a resistant package that can beOffers a resistant package that can be

transported long distances beforetransported long distances beforegerminatinggerminating

The “trunk” of a seed fern

Key moments in Animal Kingdom• Silurian saw development of fishes

- Fishes with bony structures on the outside

• includes a group called the Ostracoderms- "shell-skins"

• includes a group called the Agnathids- Hagfish and Lampreys (i.e., jawless fishes)

• Includes a group called Placoderms- "plate-skins"

Key moments in Animal Kingdom• Silurian saw development of fishes

- Fishes with bony structures on the outside

• includes a group called the Ostracoderms- "shell-skins"

• includes a group called the Agnathids- Hagfish and Lampreys (i.e., jawless fishes)

• Includes a group called Placoderms- "plate-skins"



Reconstruction of ostracoderm Pteraspis





A Placoderm fish about to munch on an unsuspecting lobe-finned fish

Chondricthyans "cartilagenousfish"

• includes sharks, skates, and rays• developed in late Silurian and becamedominant in late Devonian- Have existed relatively unchanged for 375million years!

Chondricthyans "cartilagenousfish"

• includes sharks, skates, and rays• developed in late Silurian and becamedominant in late Devonian- Have existed relatively unchanged for 375million years!

Osteichthyans "bony fishes"Osteichthyans "bony fishes"• • these show up in Devonian as wellthese show up in Devonian as well• • eventually giving rise to Tetrapodseventually giving rise to Tetrapods

- - organisms that will eventually colonize theorganisms that will eventually colonize thelandland

Colonizing land - animal kingdomColonizing land - animal kingdom• • Arthropods were first complex animals toArthropods were first complex animals tocolonize the landcolonize the land

- - bugs!bugs!

• • Amphibians were the first vertebrates toAmphibians were the first vertebrates tomove onto landmove onto land

- - still tied to the water for reproduction thoughstill tied to the water for reproduction though

Evolutionary links between lobe finsEvolutionary links between lobe finsand tetrapodsand tetrapods

Chondrichthyes fossilChondrichthyes fossil• • a fossil skate a fossil skate

- - related to sharksrelated to sharks- - and stingraysand stingrays

Coelocanth fishCoelocanth fish• • lobe finned fishes are classified aslobe finned fishes are classified as

Sarcopterygians and CrossopterygiansSarcopterygians and Crossopterygians

During the Carboniferous andDuring the Carboniferous andPermian insects like dragonfliesPermian insects like dragonfliesgot very largegot very large

• • Permian dragonfly had a wingspan of 1.5Permian dragonfly had a wingspan of 1.5meters!meters!

Permian TetrapodPermian Tetrapodamphibian amphibian CacopsCacops

Permian Reptile- DimetrodonPermian Reptile- Dimetrodon

a late Permian tetrapod a late Permian tetrapodamphibianamphibian

4 big extinction events during the4 big extinction events during thePaleozoicPaleozoic

• • OrdovicianOrdovician• • SilurianSilurian• • DevonianDevonian• • PermianPermian

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Paleozoic (542-251 mya) events