Birds

Question 1

Characteristics of class Aves

Answer 1

-Adaptations for flight
Wings, feathers
Endothermy
High metabolic rate
Modified vertebral column for flight
Light bones
Horny bill, no teeth

Question 2

Anatomical similarities of birds to reptiles

Answer 2

Single occipital condyle on skull
Single ear ossicle
Similar lower jaw structure

Question 3

Physiological similarities of birds to reptiles

Answer 3

Nucleated RBC’s
Similarities in certain aspects of liver and kidney function

Question 4

Behavioural similarities to reptiles

Answer 4

Nesting and care of young

Question 5

convincing evidence that supports theropod ancestry hypothesis

Answer 5

-Dinosaur fossils with furcula (wishbone)
-Fusion of clavicles an adaptation for flight in birds

Question 6

Oldest “bird” discovered
Very close to main line ofevolution between reptilesand birds (transitional forms

Answer 6

Archeopteryx
-long reptilian tail, clawed fingers
Imprints of feathers on tail and wings – evidence that it was a bird

Question 7

Why is Archeopteryx also important in terms of developing hypotheses on origin of flight

Answer 7

-Wishbone well developed
-May have been a glider or able to fly short distances
-Clawed digits on wings

Question 8

What is the proposed sequence of evolution of flight:

Answer 8

Jumping branch to branch or branch to ground → gliding → weak flapping to supplement gliding → wing powered flight

Question 9

What are the two primary functions essential for flight of Feathers?

Answer 9

Provide lift and steering
Prevent excessive heat loss – maintain high metabolic rate

Question 10

Importance of Feathers

Answer 10

-essential for flight
-roles in courtship, incubation, waterproofing

Question 11

What are the types of Feathers

Answer 11

-Pennaceous Feathers
-Filoplumes
-Plumulaceous Feathers
-Powder down Feathers

Question 12

Which type of feather are:
Highly specialized; found on herons, bitterns, hawks, parrots
Tips disintegrate releasing powder for waterproofing

Answer 12

Powder down Feathers

Question 13

Which type of feather are:
hair-like, degenerate; no known function

Answer 13

Filoplumes

Question 14

Which type of feather are:
Contour feathers – give bird outward form
Flight feathers - contour feathers that extend beyond body (wings, tail) and used for flight

Answer 14

Pennaceous Feathers

Question 15

Which type of feather are:
Lack prominent rachis; barbules lack hooks
Hidden beneath contour feathers
Insulation
Abundant on breast and abdomen of water birds

Answer 15

Plumulaceous Feathers

Question 16

T/F
Molting is orderly process

Answer 16

True, except for penguins

Question 17

Adaptive features of bird skeleton

Answer 17

-Reduced number of skull bones
-Bill instead of teeth
-Pelvic girdle, vertebral column and ribs strengthened for flight

Question 18

T/F
Largest and strongest muscles are flight muscles

Answer 18

True

Question 19

Process of Flight

Answer 19

-Bird wings form air foil
-Upper surface slightly convex / lower surface slightly concave
-Air passing over travels farther and faster than air passing under
-Air pressure on upper surface decreases and lift is created
-Forward thrust is produced during downstroke of wing
-Slotted feathers at wing tips or presence of alula reduce turbulence

Question 20

Process of Flapping Flight

Answer 20

-Downstroke:
Outer wing moves down, slightly forward and rotates  lower edge is below trailing edge
-Upstroke:
Wing folds slightly and returns to original position with minimum drag

Question 21

How hummingbirds have unique wing structure

Answer 21

Wing is nearly rigid but hinged at shoulder by swivel joint and powered by enlarged supracoracoideus muscle
Hovering – wing moves in sculling motion
Provides lift without propulsion on both forward and backstroke

Question 22

How bird’s stomach modified into two regions

Answer 22

-Proventriculus – secretes gastric juices
-Ventriculus (gizzard) – with muscular wall to crush, abrade seeds, nuts etc.

Question 23

Birds eliminates food through?

Answer 23

cloaca

Question 24

Birds also use a _____________ system but also have a special mechanism that allows one-way flow over gas exchange surfaces

Answer 24

negative pressure system

Question 25

Birds have tunnel-like passages
where gas exchange happens

Answer 25

parabronchi

Question 26

T/F
Forebrain of birds much smaller than that of reptiles

Answer 26

False, Forebrain of birds much larger than that of reptiles

Question 27

How is forebrain of birds much larger than that of reptiles

Answer 27

-Cerebral hemispheres enlarged including grey matter area = corpus striatum
-Visual learning, feeding, courtship, nesting

Question 28

What regulates temperature of eggs

Answer 28

Most birds incubate eggs; some have featherless, highly vascularized brood patch

Question 29

Characteristics of Altricial young in birds?

Answer 29

-dependent and often bare at birth
-Must be brooded constantly at first- endothermy not developed yet
-Grow fast, and when leave nest, almost same size as parents

Question 30

Characteristics of Precocial young in birds?

Answer 30

-more independent at birth
-Alert, lively, covered with down; can walk, run, swim, feed themselves
-One parent remains present to lead young to food and shelter