Avians

  • Created by: phoeberb
  • Created on: 16-05-19 19:34
How have modern birds evolved since the archaeopteryx?
expanded brain case, fused tibia/ulna and radius/ulna, reduced and fused tail vertebrae, sternum expanded to form keel, fused manus and pelvic bones
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paleognath and neognath palate structures
paleognath- large vomer, small palatine. neognath- palatine juxtaposed, small vomer
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What birds are paleognaths?
Ratites (flightless birds) and Tinamous
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Avian skull main features
Maxilla, Mandible, Cranium, Orbital socket, hyoid apparatus, zygomatic arch
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avian beak features
premaxilla covered by rhampotheca (beak/bill), keratinocytes and corneocytes form outersheath.
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Why do birds have no teeth?
evolutionary side effect of having less incubation periods which increases vulnerability
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Avian digestion sites
Crop, Gizzard, Protoventiriculus
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Features of the crop
stores swallowed food, can produce milk in pigeons, reduced in carnivores and increased in seed eaters.
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features of the gizzard
muscular part grinds food, has gastroliths
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what does the protoventriculus do?
secrete HCI and pepsinogen
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how is the forelimb modified?
alula on digit 1, distal tip (made of phalange 2), carpometacarpus (primary remiges), bowed ulna (quit knobs)
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Types of feathers on the forelimb
primary remiges (metacarpal to phalanges), Tertiary and secondary remiges (Ulna)
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wings in flight
wings twist inwards and primaries open on upstroke, alula and raised on landing
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features of pennaceous feather
Stalk or quit embedded in in the skin, vaned or shafted, asymmetric
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Flight muscles of the keel
Pectoralis muscle over the top of the supracoracoideus muscle
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avian respiration inhalation 1, exhalation 1
air travels through the trachea to the posterior air sacs and travels into the parabronchi were gas exchange occurs
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avian respiration inhalation 2, exhalation 2
air from the parabronchi travels to the anterior air sacs where it is held till exhalation, air is then released through the trachea
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features of the synsacrum
synsacrum is fused to the pelvis. is a rigid unit to decrease the need for flight muscles to maintain flight pressure
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features of the pygostyle
posterior caudal vertebrae which support the retrices
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male organs
testes next to kidneys, vas deferens takes sperm to cloaca
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female organs
ovary, infidibulum (oviduct), shell gland (uterus), vagina, cloaca
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how does the egg form?
ova enter infundibulum (uterus) fertilisation in 15 minutes, shell membranes deposited in oviduct (4.5 hrs), fully formed shell deposited in shell gland (20 hrs) vagina to cloaca
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Briefly describe living bird clades
Paleognaths (ratites and tinamous), neongnaths, galloanserae (ducks and chickens), eufalconiformes (falcons, parrots, passerines), accipitrimorphae (hawks, owls, woodpeckers, kingfishers), strisores (nightjars, swifts, hummingbirds and allies)
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Other cards in this set

Card 2

Front

paleognath and neognath palate structures

Back

paleognath- large vomer, small palatine. neognath- palatine juxtaposed, small vomer

Card 3

Front

What birds are paleognaths?

Back

Preview of the front of card 3

Card 4

Front

Avian skull main features

Back

Preview of the front of card 4

Card 5

Front

avian beak features

Back

Preview of the front of card 5
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