vertebrates; birds

Question 1

birds evolved from

Answer 1

small, predatory dinos

Question 2

evolution of birds

Answer 2

• transition from fuzz to flight feathers
• loss of teeth
• loss of tail
• fusion and modification of skeletal elements

Question 3

intermediates between dinos and birds

Answer 3

• archaeopteryx: ancestral reptilian traits, derived bird-like traits, flight feathers
• aurornis: clawed digits on forelimb, sharp teeth, dino fuzz, unable to fly
• anchiornis:

Question 4

most basal bird

Answer 4

aurornis

Question 5

feathers likely appeared in

Answer 5

compsognathids

Question 6

which dino-bird intermediate had feathers of modern birds

Answer 6

archaeopteryx

Question 7

describe changes in digits

Answer 7

• therapods had forelimbs with small 4 and 5 digits, digit 3 longest
• ceolophysoids, digit 5 lost, digit 2 and 3 equal
• in allosaurids, digit 4 lost, and 2 because longer than 3

summary
- 5 lost first, 2 grew to be equal to longest 3
- 4 lost, 2 become longer than 3
- so in living birds they have 1, 2, 3 and 2 is longest

Question 8

other evolvements of birds

Answer 8

• reducted, loss and fusion of skeletal elements
• reduction in body size
• outer cortex of bones thinner but more sense
• bones hollow or have trabeculae

Question 9

bird sternum evolution

Answer 9

became larger and evolved a central keel to anchor the flight muscles

Question 10

bird evolution forelimbs

Answer 10

became longer than hindlimbs as main form of locomotion switched from running to flying

Question 11

bird evolution teeth

Answer 11

lost

Question 12

flightless birds

Answer 12

LOST the ability to fly secondarlily

Question 13

success of birds because

Answer 13

• endothermic
• flight

Question 14

beak

Answer 14

keratinized structure derived from skin
grows continuously

Question 15

uropgyial gland

Answer 15

• dorsal surface of tail
• 2 lobes that open to single papilla
• lipoid secretion; waterproof and moisturize feathers
• preen to distribute

Question 16

3 types of feathers

Answer 16

• contour; cover most of body, aerodynamics, protection
• flight; larger and stiffer, wings, tail
• down; between contour and flight, insulation

Question 17

natal down feathers

Answer 17

fuzz on chicks

Question 18

bird bones

Answer 18

light but v strong, greater content of CaPO4 than mammalian bone

Question 19

bird invasion by diverticula of air sacs:

Answer 19

pneumatic bones

Question 20

bird skull evolved from

Answer 20

diapsid reptilian skull

Question 21

bird skull evolution

Answer 21

• enlarged cranium
• jaws toothless, and covered by beak
• skull pro kinetic (premaxilla and nasal bone form hinge w frontal bone, upper jaw can be raised while lower jaw depressed)

Question 22

bird sternum keel

Answer 22

large, mid ventral keel in flying birds, attachment for flight muscles, absent in flightless birds except penguin has

Question 23

bird lungs

Answer 23

small, flattened, rectangular
unlobed
dense
communicate with air sacs

Question 24

air sac

Answer 24

blind ending, thin walled extensions of bronchi, key role in resp but minimal role in gas exchange

Question 25

birds have ____ circulation

Answer 25

double: systemic and pulmonary

Question 26

birds have ____ metabolic rate than mammals

Answer 26

higher

Question 27

reproduction: males have a

Answer 27

phallus; tubercle on central wall of vent
phallus pressed to females cloaca

Question 28

female ovary and oviduct

Answer 28

left ovary and left oviduct

Question 29

ovary has very large

Answer 29

yolk-filled oocytes

Question 30

what is the site of fertilization

Answer 30

oviduct

Question 31

brain

Answer 31

• small
• large cerebellum, for coordination of muscle activity and balance in flight
• v large optic lobes