Aves birds Most scientists refer to this group as Sauropsida Birds are a part

Aves birds most scientists refer to this group as

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Aves: birds Most scientists refer to this group as Sauropsida Birds are a part of the Dinosauria clade. Why? This means dinosaurs are still around! All non-avian dinosaur clades died off in the Cretaceous extinction
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Tetrapods: Reptiles Emerald tree boa Vestigial hind limb bones Broad-tailed hummingbird
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Xiatingia zenghi Birds are thought to have evolved from theropod dinosaurs during the Jurassic period Archaeopteryx and Xiaotingia are pre-birds which were close relatives (but not the ancestors) of modern birds Archaeopteryx lithographica Reptiles: Birds
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Synapomorphies which contribute to flight: Feathers – modified scales Air sacs – pump air through lungs and bones Reduction of organs Lightweight bones Reptiles: Birds
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Reptiles: Birds Tons of diversity – over 10k species!
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National Geographic, 2013 Tons of diversity – over 10k species! Reptiles: Birds
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Mammals
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Mammal Phylogeny Over hundreds of millions or years, synapsids eventually give rise to mammals
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Mammals § Synapomorphies that arose in the mammal MRCA: Mammary glands – secrete milk (fats + sugars + proteins + vitamins + antibodies!) Hair – made of keratin (also makes up reptile scales and feathers!)
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  • Spring '14
  • Evolution, placental mammals, tetrapods

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