Birds

Question 1

What class are birds in?

Answer 1

Aves.

Question 2

What did birds evolve from?

Answer 2

Theropod dinosaurs.

Question 3

When did true birds appear?

Answer 3

Cretaceous.

Question 4

When did birds diversify?

Answer 4

Tertiary.

Question 5

What are the two major bird clades?

Answer 5

Paleognathae and neognathae.

Question 6

Give characteristics of Paleognathae.

Answer 6

No keel, flightless.

e.g. ostrich.

Question 7

Give characteristics of Neognathae.

Answer 7

Flexible palate.
Possess carina/sternal keel.
Includes penguins.

Question 8

What are the three main foot formations in passeriformes?

Answer 8

Anisodactyly - 3 forward, 1 back.
Zygodactyly - X shape.
Pamprodactyly - 4 forward.

Question 9

What skull fenestration do birds have?

Answer 9

Diapsid.

Question 10

What is a gizzard?

Answer 10

Muscular structure used to grind up and process food. Sometimes filled with pebbles birds eat to mechanically grind up food.

Question 11

What is a toucan bill like?

Answer 11

Biocomposite beak, interior is rigid foam composed of bony fibres and the exterior is made of keratin.

Question 12

What is a woodpecker bill like?

Answer 12

Spongy bone at the site of impact between the beak and skull as a cushion. Longer lower parts of mandibles direct force away from the brain.

Question 13

Are birds ovi, ovovivi or viviparous?

Answer 13

Oviparous.

Question 14

How can birds conserve heat?

Answer 14

Draw beak and feet into plumage.
Counter-current heat exchange, arteries going in and veins going out in close proximity recapture heat and save it.
Torpor or hibernation.

Question 15

What is a bird’s circulatory system like?

Answer 15

4-chambered heart.

Larger body size:heart mass ratio compared to mammals.

Question 16

What is a bird’s respiratory system like?

Answer 16

Unidirectional airflow.

Question 17

Compare bird and reptile senses.

Answer 17

Reduction in smell in birds.
Expansion in optic lobes. - provide larger and sharper images.
Expansion of forebrain. .

Question 18

Describe avian vision.

Answer 18

3 eyelids.
4 photoreceptors (tetrachromatic vision).
Can see UV colours.

Question 19

Describe magnetic vision.

Answer 19

Magnetic sense dependent on light. Avian compass arises in the protein cryptochrome, found in rod cells of retina.

Question 20

Describe avian hearing.

Answer 20

Has 3 sections, outer ear, middle and inner ear.
Nocturnal birds of prey use hearing, diurnal ones use vision.
Owls has asymmetric ear openings and a facial mask to guide sounds into their ears.

Question 21

What do birds use echolocation for?

Answer 21

Navigation in dark.

Question 22

How did the forelimb become the wing?

Answer 22

Humerus, radius and ulna similar.
Carpals fuse.
Digits reduce.
Primaries on hand, secondaries on arm.

Question 23

How did the pectoral girdle adapt?

Answer 23

• Wings above centre of gravity.
• Sternum forms keel from which flight muscles attach.
• Clavicle fused to form wishbone.
• Wishbone prevents collapse of girdle mid-flight.

Question 24

What are the major flight muscles?

Answer 24

Pectoralis - pulls wing down (large).

Supracoracoideus - pulls wing up.

Question 25

What are skeletal adaptations of birds?

Answer 25

Vertebral column becomes fused and rigid. Ligaments become ossified. Lumbar vertebrae form synsacrum. Increased cervical vertebrae for flexible neck. Caudal vertebrae form pygostyle (tail feathers).

Question 26

What is flapping flight?

Answer 26

Propulsion from primaries. Lift from secondaries. Drag reduction from alula, coverts and rectrices.

Question 27

What are causes of drag?

Answer 27

Frictional drag from air resistance. | Induced drag from formation of vortices at wingtips when airflow is separated from airfoil.

Question 28

How do birds minimise drag?

Answer 28

Streamlining (no external ears, feet tucked in, feather and wing shape). Tails spread at low speeds, become furled with increasing speed. Fly in wake of other birds.

Question 29

How do you calculate aspect ratio?

Answer 29

Wing length / wing width.

Question 30

How do you calculate wing loading?

Answer 30

Mass / wing area.

Question 31

What are down feathers?

Answer 31

Loosely structured feathers beneath contours which help trap air near body for warmth.

Question 32

What are semiplumes?

Answer 32

Loose and fluffy feathers provide insulation and increase water bird buoyancy.

Question 33

What are filoplumes?

Answer 33

Small hair-like feathers with a few barbs at the top, occur among contours.

Question 34

What are bristle feathers?

Answer 34

Vaneless contours with a few barbs at base, around eyes, nostrils and mouth.

Question 35

What are powder down feathers?

Answer 35

Continuously growing and are never moulted, disintegrate into powder.

Question 36

What are contours?

Answer 36

Form outer covering of bird, includes primaries, secondaries and tail feathers.

Question 37

What is migration?

Answer 37

2-way movement between breeding and wintering areas. Usually based on season and driven by availability of food. More frequent in Northern Hemisphere.

Question 38

What are the dangers of migration?

Answer 38

``` Possible competition changes. Energy expenditure. Predation. Collision. Hazardous journey, unknown new habitats? Timing. Endurance performance. Navigation. ```

Question 39

What are the sex chromosomes of birds?

Answer 39

ZW for female, WW for male.

Question 40

What does precocial mean?

Answer 40

Needs less parental care.

Question 41

What does altricial mean?

Answer 41

Needs more parental care.

Question 42

What is polygyny?

Answer 42

A male bird breeds with >1 female.

Question 43

What is polyandry?

Answer 43

When a female bird abandons her eggs to breed with more than one male.

Question 44

What is lekking?

Answer 44

Cluster of males attack females, males provide nothing but sperm.