Bio153_Lecture17_reptiles-birds_sv

Bio153_Lecture17_reptiles-birds_sv - Why live on land?...

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Deuterostomate Animals: Reptiles, Birds Why live on land? 1) abundant O 2 2) less competition 3) less predation (esp. in reproduction) New adaptations: Vertebrate Fossil Record: Key Innovations Bony exoskeleton Jaws and teeth Limbs capable of moving on land Amniotic egg F irs t ve rteb ra te s t ca rtila g in o u fish es t fish w ith ex ten si v e b n t b y jaw t te trap d t am io Cambrian Ordovician Silurian Devonian Carboniferous Mississippian Pennsylvanian Permian amniotic egg: significant because it gave vertebrates the ability to reproduce away from water • Amniota: all vertebrates with extra-embryonic membranes surrounding the egg Rise of the Reptiles cotylosaurs: early reptiles 318myo reptile footprints Bay of Fundy, NB Rise of the Reptiles • adaptations to life on dry land: 1) shelled amniote egg 2) internal fertilization
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Rise of the Reptiles • adaptations to life on dry land: 3) water-conserving kidneys 4) gas exchange through well-developed lungs thoracic breathing – contraction of muscles expand rib cage that draws air in Rise of the Reptiles adaptations to life on dry land 5) tough scaly skin; scales contain keratin Rise of the Reptiles adaptations to life on dry land 6) 4-chambered heart less mixing of blood - higher blood pressure crocodilians: complex heart: able to shut down blood flow through the pulmonary circuit, allowing them to stay submerged in water without breathing for long periods Rise of the Reptiles adaptations to life on dry land
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This note was uploaded on 02/01/2012 for the course BIOLOGY 153 taught by Professor Dr.arts during the Fall '10 term at University of Toronto- Toronto.

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Bio153_Lecture17_reptiles-birds_sv - Why live on land?...

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