evolution of flight

Question 1

archaeoptrix

Answer 1

suspected to start the evolution of flight, showed fusion of bones in the foot, had the characteristic long curved neck, had clawed forelimbs and lacked a keeled sternum making it unlikely that they flew

Question 2

cursorial flight hypotheses

Answer 2

ground up hypothesis in which birds first gained the ability to run and jump; assuming a bipedal ancestor with large long legs

Question 3

arboreal flight hypotheses

Answer 3

trees down hypothesis first developing climbing and gliding; requires a clawed ancestor, short hand wings and long arm wings, and large attachment sites on the humerus

Question 4

ichthyornithiformes

Answer 4

tern-like fish eaters with modern flight adaptations including a keeled sternum lost and fused bones, had teeth; cretaceous

Question 5

enantiornithes

Answer 5

opposite birds, have a reversed fusion pattern of tarsal elements relative to modern birds, well developed flight apparatus and a primitive pelvis; likely an extinct side branch; cretaceous

Question 6

hesperornithiformes

Answer 6

very large flightless diving birds, fish eaters, loon like, vestigial wings and an unkeeled sternum with some fusion of bones; indicates possible loss of flight; cretaceous

Question 7

neornithine

Answer 7

transitional shore birds, stem groups for modern, thought to give rise to wading, shore, and waterfowl; cretaceous

Question 8

Tertiary birds

Answer 8

Extensive adaptive radiation and development of large flightless carnivores to fill Dinosaur niches

Question 9

Phorysrhacids

Answer 9

Much lighter than other tertiary birds but still very tall and with a hooked bill indicating predation

Question 10

Pleistocene period

Answer 10

Dramatic climate change and radiation, general decline and extinction in bird species, several large flightless species

Question 11

Evolution of flightlessness

Answer 11

Costs of flight outweigh benefits, has developed multiple times, often a result of geographical isolation

Question 12

Modifications associated with flightlessness

Answer 12

Reduction of flight bones and muscles and the pelvic girdle, loss of keeled sternum, tendency towards large size typically occurs via arrested embryonic development

Question 13

Neotomic features of flightless birds

Answer 13

Sternum late to form and ossify

Question 14

Avian systematics

Answer 14

Evolutionary relationships among organisms along with classification

Question 15

Aves subclasses

Answer 15

Sauriurae, ornithurae

Question 16

Sauriurae infraclasses

Answer 16

Archaeornithes: archaeoptryx
Enantiornithes: opposite birds

Question 17

Ornithurae infraclasses

Answer 17

Odontornithes: toothed birds
Neornithes: all extant bird species

Question 18

Neornithes superorders

Answer 18

Paleognathae: ratites and tinamous
Neognathae: all others

Question 19

order Passeriformes

Answer 19

songbirds;
primitve suboscine dominate South America
advanced oscine dominates the rest of the world
Feet adapted for perching, highly altricial hatchling, unique sperm and plate structures

Question 20

gastornis

Answer 20

very large tertiary birds, heavy bodied with thick bills predation unknown