Exam 4 Ch 19 Flashcards
What four evolutionary trends were discussed with Aves in lecture?
- reduction of body size
- reduction (fused) digits
- preumatic bone (not completely hollow, but not solid)
- feathers.
What is the difference between symmetrical and asymmetrical feathers?
Symmetrical feathers are for warmth, whereas asymmetrical feathers are for flight.
in what year was Archaeopteryx lithographica discovered?
1861
List the theropod characteristics discussed in lecture.
- ???
- legs under body
- bipedal (walk on two legs)
- long tail
- lightweight bones
- nest makers
- teeth
- claws on front limbs
What three characteristics do birds have that theropods dont?
asymmetrical feathers
keel-like sternum
furcula (wishbone)
What are the two groups of modern birds?
Paleognaths and Neognaths
True or false. Paleognaths are flightless birds.
True.
What two characteristics were discussed in lecture inn regard to Paleognaths?
a flat sternum
poorly developed pectoral muscles
True or False. Neognaths are the largest group of birds and do not include penguins.
False.
What two characteristics distinguish Neognaths from Plaeognaths?
a keeled sternum
well-developed pectoral muscles
True or False. Aves are the second largest group following fish in vertebrates.
True.
How many Avian species have been identified?
10,400+
True or false. Aves live in all biomes.
True.
What hallmarks of avian diversity were mentioned in lecture?
feathers/flight hind limbs adapted for walking, swimming, perching lay eggs Wings: present for lift and propulsion Bones: provides light rigid airframe
What parts of feather anatomy were discussed in lecture?
Quill, vane, barb, barbules, and shaft
True or False. Feather growth and development is different than scales in reptiles.
False. They are the same.
Explain feather growth and development.
formation of out growth, follicle, then epidermal ridges (which give rise to barbs and barbules.)
Then the surrounding sheath degenerates
True or False. Feathers molt multiple times a year.
False. They generally molt once a year after nesting.
What three molting patterns were discussed in lecture?
- Most: pairs of flight and tail feathers lost to maintain balance.
- continuous replacement
- primary feathers are lost all at once. (water birds can’t fly, so easy predation.)
What are pneumatized bones?
strong but light weight bones
What four characteristics of Avian skulls were discussed in lecture?
- large braincase and orbits
- one occipital condyle at the base of the skull which allows for more rotation for the skull.
- Diapsid but not easily determined and modified
- Keratinized beak molded around bony jaws
True or False. All avian vertebrae are fused except cervical vertebrae (neck bones).
True.
What is the pygostyle?
equivalent to the coccyx in humans. It is the tail vertebrae, fused and shortened.
What is the synsacrum?
a light and thin sacrum. has fused sacral vertebrae and pelvic girdle.
What is the uncinate process?
extra section of ribs braced against each other to brace for landing. (look up again.)
True or False. Aves have a fused clavical form of furcula or wishbone.
True.
True or false. The sternum in birds has a large keel. This helps attach powerful muscles to the skeleton.
True.
Forelimbs are modified for flight and…
some bones are reduced in number or fused.
What two muscles are adapted for flight in birds?
the pectoralis and the supracoracoideus.
What is the pectoralis muscle in birds?
the largest, outermost muscle that depresses (pulls down) wing during flight. It attached underneath the humerus.
What is the supracoracoideus muscle in birds?
it raises wings, lays under the pectorals, and snakes above to attached to the top side of the humerus.
True or False. Both the pectoralis and supracoracoideus muscles attach to the keel.
True.
What are the advantages to the main leg muscle mass in the thigh of Aves?
connects to the feet and toes by long tendons.
Allows for a locking mechanism with perching tendons, which enable a bird to sleep in a perching position and not fall off.
What adaptations for flight were discussed in regards to food, feeding and digestion?
- rapid digestion
- long, muscular esophagus
- the crop allows them to eat a lot and process as it goes
- stomach
- paired ceca that form fermentation chambers
- cloaca
- varied food habits
What are the two parts of the stomach in Aves called?
the proventriculus which secretes gastric juices and the gizzard for grinding food.
What is the difference between stenophagous and euryphagous?
stenophagous means they have a specific diet, euryphagous means they can eat a varied diet.
What three adaptations for flight were produced in the Aves circulatory system?
a four chambered heart
their heartbeat is inversely proportional to size
blood cells have nucleated biconvex RBCs and phagocytes for repairing wounds and destroying microbes.
How is the Avian respiratory system adapted for flight?
they have the most efficient system of terrestrial vertebrates
9 air sacs that extend into the thorax and abdomen.
takes 2 respiratory cycles for a single breath to pass through a system
How is the Avian excretory system adapted for flight?
- two large metanephric kidneys (like us) w thousands of nephrons. (look like large nephridia clumped together.)
- concentration of uric acid in the cloaca (absorbs water)
- Marine birds (due to large salt loads) have salt glands that remove excess salt from the seawater they drink.
How is the Avian nervous system adapted for flight?
- they have well developed cerebral hemispheres (problem solving) and a well developed cerebellum (balance and coordination) as well as a well developed optic lobe (big eyes.)
- poorly developed sense of smell (except in flightless, oceanic, and waterfowl)
- good hearing but no pinna. have a hole in skull like reptiles.
- Excellent vision
How is Avian vision adapted for flight?
- eyes are large relative to body size
- less spherical and almost immobile
- The retina has rods and cones, a pecten, or highly vascularized organ that connects to the retina and serves to bring more oxygen to cue.
- 2 foveae for sharp monocular and binocular vision.
Explain the male reproductive system in Aves.
- 2 testes that remain small until mating season, then grow large to mate.
- no portusible (protruding) copulatory organ (penis)
- pushes cloaca together.
Explain the female reproductive system of Aves.
- only the left ovary and oviduct develops fully.
2. right side degenerates but can develop if the left side is injured or non-functionable.
Explain egg formation in Aves.
- fertilization occurs in upper oviduct (sperm can live there for several days)
- lay one egg a day
- glands add albumin as egg passes down oviduct
- The shell, membrane and pigments added in uterus.
