Term
| Features shared by Birds + Reptiles |
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Definition
1. skull articulation w/ neck vertebrae (occipital condyle)
2. scales (keratin), feathers (present in dinosaurs)
3. heterogametic sex (females ZW)
4. nucleated red blood cells
5. yolked eggs: ovipary (present in some) |
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Term
| Diagnostic features of birds |
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Definition
1. feathers
2. bill and lack of teeth
3. specialized furcula
4. reversed first toe (hallux)
5. bone fusion and reduction
6. pneumatic (hollow) bones
7. bipedalism and digitigrade feet
8. forelimbs specialized for flight (wings)
9. centralized body mass
10. well developed central nervous system and vision
11. endothermic and high metabolic rate
12. grow fast
13. lay shelled eggs that require parental care, build nests |
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Term
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Definition
the most diagnostic feature of birds
insulate, protect/waterproof, form wings and tail used in flight |
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Term
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Definition
horny bill to cover jaws
lighter than teeth
remarkable functional diversity in bills |
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Term
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Definition
wishbone
fused clavicles
serves as energy storage spring |
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Term
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Definition
hallux
in perching birds, allows vice-like grip on branches
lets flying animals land in trees |
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Term
| bone fusion and reduction |
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Definition
many fused bones- skeletal rigidity provides stronger frame for flight muscles
lost bones- no bony tail |
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Term
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Definition
hollow bones
unique in extent and complexity of pulmonary system
many large bones have direct connections to air sacs and respiratory system |
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Term
| bipedalism and digitigrade feet |
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Definition
Bipedal- walk on two legs (like theropod dinosaur ancestors)
-implications for evolution of flight
Digitigrade- walk on toes
what looks like knee is ankle
mammals are plantigrade since they walk on foot bones
birds tarsal and metatarsals fused and foot fused |
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Term
| forelimbs specialized for flight (wings) |
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Definition
pectoral limbs highly modified for flight
secondarily lost in a few taxa |
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Term
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Definition
flight muscles on body, not wings
control wing through tendons
concentrating mass in center increases stability in flight |
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Term
| well developed central nervous system and vision |
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Definition
brains 6-10 times of brains similar-sized reptiles
incredible feats of navigation possible (butterflies)
excellent color vision and UV vision (lots of signals)
lots of learning, important in social behavior, complex song, motor skills |
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Term
| endothermic and high metabolic rate |
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Definition
part of metabolic rate due to endothermy, which is costly
part due to big brains
evolution of endothermy interesting in own right, related to flight? |
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Term
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Definition
determinate growers: at maturity little size variation within species/sexes)
most fish or herps are indeterminate growers |
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Term
| lay shelled eggs that require parental care, build nests |
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Definition
only vertebrate group that lack livebearers (vivipary)
lay one egg at a time rather than entire clutch
all show parental care (90% of birds, males are good dads)
unlike leathery reptile eggs, shells have brittle layer composed of calcium carbonate crystals |
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