Ordovician The first vertebrates - jawless fishes called ostracoderms.

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Ordovician The first vertebrates - jawless fishes called ostracoderms
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Transcript of Ordovician The first vertebrates - jawless fishes called ostracoderms.

Page 1: Ordovician The first vertebrates - jawless fishes called ostracoderms.

Ordovician

The first vertebrates - jawless fishes called ostracoderms

Page 2: Ordovician The first vertebrates - jawless fishes called ostracoderms.

Ordovician

Reef-forming corals called rugose corals

Page 3: Ordovician The first vertebrates - jawless fishes called ostracoderms.

Ordovician

Eurypterids or sea scorpions - up to 2 m long

Page 4: Ordovician The first vertebrates - jawless fishes called ostracoderms.

OrdovicianMajor radiation of trilobites and brachiopods

Page 5: Ordovician The first vertebrates - jawless fishes called ostracoderms.

Ordovician mass extinction Occurred at the end of the Ordovician

Second largest mass extinction, especially for marine animals

Apparently caused by movements of southern continents toward the South Pole

Cooler climate caused more tropical species to go extinct

Water tied up in glaciers caused sea level to fall

Page 6: Ordovician The first vertebrates - jawless fishes called ostracoderms.

Silurian

First land animals (millipedes, centipedes, arachnids)

Page 7: Ordovician The first vertebrates - jawless fishes called ostracoderms.

SilurianFirst jawed fishes (placoderms)

Page 8: Ordovician The first vertebrates - jawless fishes called ostracoderms.

Silurian

Appearance of first higher plant, CooksoniaThis plant had neither leaves nor roots

Its stem projected 10 cm high from which spores were released for dispersal

Page 9: Ordovician The first vertebrates - jawless fishes called ostracoderms.

Devonian

First insects (both winged and wingless species)

Page 10: Ordovician The first vertebrates - jawless fishes called ostracoderms.

Devonian

First trees and first forests

Page 11: Ordovician The first vertebrates - jawless fishes called ostracoderms.

Devonian

Explosive radiation of modern fishes Associated with extinction of many jawless fishes

Two major groups• Ray-finned fishes (Actinopterygii)

• Lobe-finned fishes (Sarcopterygii)

• The pectoral and pelvic fins of the lobe-finned fishes had fleshy central portions unlike the ray-finned fishes

Page 12: Ordovician The first vertebrates - jawless fishes called ostracoderms.

Devonian

First sharks

Page 13: Ordovician The first vertebrates - jawless fishes called ostracoderms.

Ray-finned fish

Page 14: Ordovician The first vertebrates - jawless fishes called ostracoderms.

Coelacanths

Page 15: Ordovician The first vertebrates - jawless fishes called ostracoderms.

Coelacanth distribution

Page 16: Ordovician The first vertebrates - jawless fishes called ostracoderms.

Lungfishes

Page 17: Ordovician The first vertebrates - jawless fishes called ostracoderms.
Page 18: Ordovician The first vertebrates - jawless fishes called ostracoderms.

How to make a leg out of a fin

A sarcopterygian fin is made up of preaxial, axial and postaxial elementsTo make a leg of a fin, the axis of the limb has to curve aroundSome of the preaxials were incorporated into arm and wristThe postaxials end up as the digits

Page 19: Ordovician The first vertebrates - jawless fishes called ostracoderms.

Acanthostega - amphibian but probably fully aquatic

Page 20: Ordovician The first vertebrates - jawless fishes called ostracoderms.

Devonian

First land amphibians (Ichthyostega)

Page 21: Ordovician The first vertebrates - jawless fishes called ostracoderms.

Devonian mass extinctionAt end of Devonian

Primarily affected marine organismsRugosan corals, brachiopods, trilobites, jawless fishes and placoderms greatly affected

About 60% of existing species went extinct

What was the cause?Most species affected were warm water forms, suggesting that global cooling might have been responsible

Page 22: Ordovician The first vertebrates - jawless fishes called ostracoderms.

Carboniferous

Climate was warm and humid

Extensive coal-forming swamps

Page 23: Ordovician The first vertebrates - jawless fishes called ostracoderms.

Carboniferous

Dragonflies with 70 cm wing spans (Meganeura)

Millipedes over 2 m long

Page 24: Ordovician The first vertebrates - jawless fishes called ostracoderms.

Carboniferous

Extensive radiation of amphibians

Bewildering diversity

Two groups evolved of great importanceLissamphibia - gave rise to living amphibians

Anthracosaurs - gave rise to reptiles, birds and mammals

Page 25: Ordovician The first vertebrates - jawless fishes called ostracoderms.

Anthracosaurs

Page 26: Ordovician The first vertebrates - jawless fishes called ostracoderms.

Carboniferous

First reptiles (amniotic or cleidoic egg)