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97:, "raft" – referring to the flatness of the sternum), having a subtle keel structure or lacking one entirely. However, this classification has become disused as evolutionary studies have shown that many flightless birds have evolved from flighted birds.
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149:". Earth-Life Web Productions. Retrieved January 31, 2005.
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This stylised bird skeleton highlights the keel bone
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89:, "keel"), having a pronounced keel; and
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572:. You can help Knowledge (XXG) by
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138:Cummins, Jim (April 1, 1996). "
142:". Retrieved January 31, 2005.
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387:Flying and gliding animals
223:Fin and flipper locomotion
78:too fast to be practical.
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16:Extension of the sternum
54:is an extension of the
526:Terrestrial locomotion
470:Evolution of cetaceans
465:Origin of avian flight
450:Evolution of tetrapods
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541:Undulatory locomotion
490:Homologous structures
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21:Keel (disambiguation)
485:Analogous structures
480:Convergent evolution
147:The Anatomy of Birds
19:For other uses, see
564:This article about
536:Rotating locomotion
475:Comparative anatomy
110:Museum of Osteology
455:Evolution of birds
208:Aquatic locomotion
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445:Evolution of fish
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566:ornithology
419:Insect wing
369:Webbed foot
310:unguligrade
305:plantigrade
300:digitigrade
127:Ornithology
613:Categories
347:Cephalopod
263:Pelvic fin
233:Dorsal fin
228:Caudal fin
133:References
438:Evolution
397:Bird wing
342:Arthropod
335:quadruped
83:Carinatae
429:Wingspan
412:feathers
407:skeleton
392:Bat wing
352:Tetrapod
238:Fish fin
116:See also
64:leverage
499:Related
357:dactyly
243:Flipper
91:ratites
56:sternum
48:carinae
521:Samara
330:triped
315:uniped
93:(from
87:carina
85:(from
68:flight
40:carina
568:is a
379:Wings
364:Digit
320:biped
282:Limbs
192:wings
188:limbs
95:ratis
76:wings
50:) in
570:stub
511:Gait
402:keel
200:Fins
190:and
184:Fins
66:for
60:ribs
36:keel
44:pl.
38:or
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