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30 Cards in this Set
- Front
- Back
Describe Osteolepiformes
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- Tetrapod ancestor
- Heavily scaled - Large heads - Labyrinthodont (tooth enamel folded inward) |
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Describe Elitostegidae
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- Sister group to tetrapods
- Flatter body - Elevated eyes - Loss of dorsal and anal fins |
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What were the stem tetrapods?
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-Ichthyostega
- Acanthostega - Ventastega |
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What are some characteristics of the stem tetrapods?
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- Heavy
- 7-8 toed limbs - Some had internal fish-like gills - First to walk on land |
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Describe Tiktaalik roseae
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- Fossil found in Canada in 2006
- 385 mya (late Devonian) - "Fishapod" - Retained fin rays - Humerus with flexible wrist |
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What groups make up Lissamphibia?
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- Caudata
- Anura - Gymnophonia |
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What are some Lissamphibia synapomorphies?
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-Moist, permeable skin
- Glandular skin - Middle ear bones from fusion of columella to old operculum bones - Pedicellate teeth - Green rods - Levator bulbi |
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What are some Caudata characteristics?
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- Generalized tetrapod body plan
- Limbs splayed to side - Some are paedomorphic - Some exhibit direct development |
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What are some characteristics of Anurans?
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- Hindlimbs modified for swimming and jumping
- Elongated ilium and urostyle - Live in a variety of habitats - Most numerous of the amphibians |
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What are some characteristics of Gymnophiona?
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- Elongate and limbless
- Ring-like dermal folds (annuli) - Protrusible sensory tentacles - Fossorial lifestyle |
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What symplesiomorphies distinguish reptiles from birds and mammals?
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- Ectomorphic
- Divided atria, incompletely divided ventricle - Locomotor stance w/legs splayed to the side; lateral undulation |
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True or False, Reptiles are a polyphyletic group?
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False, they are paraphyletic
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What living members make up reptiles?
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- Testudines
- Rhynchocephalia - Squamata - Crocodilia |
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What are some synapomorphies of Testudines?
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- Shell (carapace and plastron)
- Covered in scutes - Ribs external to limb girdles - Horny beak - Flexible cervical vertebrae - Plastron may be hinged |
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What are Lepidosaurs and what groups are included?
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- Reptiles with overlapping scales
- Rhynchocephalia and Squamata |
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What are some characteristics of tuatara?
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- Lizard-like body
- Found in New Zealand - Nocturnal and frequently burrow - Low active internal body temperature |
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What groups are included in Squamata?
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- Lizards (including amphisbaenians)
- Snakes |
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What are some general characteristics of Squamates?
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- Most diverse reptiles
- Shed their skin periodically - Mobile jaws - Males have a hemipenes |
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What are some characteristics of lizards?
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- Relatively diverse
- Most are small and insectivorous - Great diversity in xeric conditions - Some exhibit tail autotomy |
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What are some characteristics of amphisbaenians?
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- Fossorial
- Elongate and limbless - Nipping tooth - Annuli - Heavy skull |
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What are some characteristics of snakes?
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- Ancestral forms likely fossorial
- Limbless, elongate - Transparent eyelids fused to cornea - No external ear openings - Forked tongue |
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What are some synapomorphies of snakes?
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- Kinetic skull
- Broad body scales - Hollow venom fangs |
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What living groups make up Archosauria?
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- Order Crocodilia
- Class Aves |
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What are some basic characteristics of crocodilians?
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- Large and semi-aquatic
- Laterally compressed tail used for propulsion - Elevated eyes and nostrils - Bony, dermal armor |
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What species make up crocodilians?
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-Crocodiles
- Alligators - Caimans - Gharials |
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What Archosaur groups are extinct?
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- Crurotarsi
- Pterosaurs - Dinosaurs |
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What are some characteristics of Pterosaurs?
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- Flying
- Late triassic to vertebrae - Wing formed from stretched skin by elongate 4th digit - Hollow bone - Enlarged sternum? |
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What are some characteristics of Dinosaurs?
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- Dominant land vertebrates from Jurassic-Cretaceous
- Ancestrally bipedal, many became quadrapedal - Made up of Saurischia and Ornithischia |
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What are Saurischians and what groups did they include?
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- "Reptile-hipped" dinosaurs
- Sauropods- Long necked herbivores - Therapods- bipedal predators such as T. Rex |
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What are Orntithischians and what groups did they include?
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- "Bird-hipped" dinosaurs
- Herbivores - Duckbills - Stegosaurs - Horned dinosaurs - Armored dinosaurs |