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16 Cards in this Set
- Front
- Back
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Are amniotes a monophyletic group? |
Yes, they appeared and diversified in the Metazoa era. |
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Early diversification of amniotes produced three patterns of holes in the temporal region of the skull.
What are they? What does each mean? |
- Anapsid: skulls that have no opening, skull is completely roofed by dermal bones (eg. turtles)
- Diapsid: skull has 2 openings, paired above the cheek a second pair in the roof of the skull. The are separated by an arch. (eg. snakes)
- Synapsid: skull has one pair of openings above the cheek, bordered by a bony arch. (eg. mammals) |
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What was the functional significance of the temporal openings? |
The large openings elevate the lower jaw through muscle attachments. |
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What are some characteristics of amniotes? |
Amniotic egg, rib ventilation, dissection-resistant skin, skeletal changes in the head, shoulder and ankle. |
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What are the 4 extraembryonic membranes? |
- amnion, cushioning the embryo - allantois, stores metabolic waste - chorion, respiratory organ - yolk sac, nutrient storage |
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What covers the body of nonavian reptiles? |
Keratinized epidermal scales |
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What is the cycle for teeth in nonavian reptiles? |
They are polyphyodont, replaced many times. |
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What type of birth do non-avian reptiles give? |
Either oviparous or viviparous. |
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How do Nonavian reptiles excrete waste products? |
Uric acid, concentrated by the kidneys. |
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How do amniotes breathe? |
Through aspiration, negative ventilation. |
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Why do crocodiles only have two ventricles that are only semi-seperated? |
To allow blood to bypass the lungs when pulmonary respiration isn't occurring. Energy isn't expended pumping the blood to the lungs unnecessarily. |
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What are the two groups of dinosaurs? |
- Saurischia (lizard-hipped)
- Ornithischia (bird-hipped) |
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What clade (of ancestral dinosaurs) do birds belong to? |
Saurischia |
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What are the two groups of Saurichian dinosaurs? |
- Carnivorous and bipedal theropods
- Herbivorous and quadrupedal sauropods (first adapted to feed on trees) |
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All Ornithischian were... |
Herbivorous! |
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When did the last of the Mesozoic dinosaurs become extinct? |
~ 65 million years ago leaving the birds and crocodilians as the only remaining lineages of the archosaurs. |
