tetrapods_amphibia.ppt

7/27/2019 tetrapods_amphibia.ppt

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Paleozoic Tetrapod

Origins/Radiation


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rhipidistian crossopterygian ancestry

mid-late Devonian (360-370 mya)

major structural changes: limbs/girdles- better support & muscle

attachments

skull/jaws- new feeding modes

vertebrae- better support

lungs


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hierarchical classification of the

tetrapod vertebrates

Tetrapoda (vertebrates with four limbs) Amphibia Lissamphibia (modern amphibians)

Gymnophiona

Caudata (salamanders)- Jurassic ~ 140 mya

Anura (frogs & toads)- Triassic ~ 200 mya


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Modern Amphibians: Lissamphibia general features:

'amphibious' life cycle (metamorphosis)

smooth, glandular skin

three chambered heart

carnivorous


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Order Anura distribution cosmopolitan except Antarctica;tropics especially

elongate hind limbs & powerful leg muscles

strong pelvis fused to the vertebral column;posterior vertebrae fused into a urostyle

feeding: sticky, protrusible tongue

reproduction: species specific vocalizations external fertilization; amplexus


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Anuran Anatomy


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protrusible tongue


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Order Caudata distribution: primarily northern hemisphere

paedogenesis- larvae becomes sexuallymature

courtship: species specific displays (visual,tactile, & chemical cues)

internal fertilization; spermatophore

transfer

eggs laid in water or moist soil; larvae;aquatic & gilled in many


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Salamander Anatomy


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A few Oklahoma Amphibians


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Amphibians of SE Oklahoma

Documents

tetrapods_amphibia.ppt