Birds Flashcards

1
Q

What class are birds in?

A

Aves.

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2
Q

What did birds evolve from?

A

Theropod dinosaurs.

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3
Q

When did true birds appear?

A

Cretaceous.

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4
Q

When did birds diversify?

A

Tertiary.

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5
Q

What are the two major bird clades?

A

Paleognathae and neognathae.

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6
Q

Give characteristics of Paleognathae.

A

No keel, flightless.

e.g. ostrich.

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7
Q

Give characteristics of Neognathae.

A

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

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8
Q

What are the three main foot formations in passeriformes?

A

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

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9
Q

What skull fenestration do birds have?

A

Diapsid.

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10
Q

What is a gizzard?

A

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

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11
Q

What is a toucan bill like?

A

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

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12
Q

What is a woodpecker bill like?

A

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.

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13
Q

Are birds ovi, ovovivi or viviparous?

A

Oviparous.

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14
Q

How can birds conserve heat?

A

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.

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15
Q

What is a bird’s circulatory system like?

A

4-chambered heart.

Larger body size:heart mass ratio compared to mammals.

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16
Q

What is a bird’s respiratory system like?

A

Unidirectional airflow.

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17
Q

Compare bird and reptile senses.

A

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

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18
Q

Describe avian vision.

A

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

19
Q

Describe magnetic vision.

A

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

20
Q

Describe avian hearing.

A

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.

21
Q

What do birds use echolocation for?

A

Navigation in dark.

22
Q

How did the forelimb become the wing?

A

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

23
Q

How did the pectoral girdle adapt?

A
  • 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.
24
Q

What are the major flight muscles?

A

Pectoralis - pulls wing down (large).

Supracoracoideus - pulls wing up.

25
Q

What are skeletal adaptations of birds?

A

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).

26
Q

What is flapping flight?

A

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

27
Q

What are causes of drag?

A

Frictional drag from air resistance.

Induced drag from formation of vortices at wingtips when airflow is separated from airfoil.

28
Q

How do birds minimise drag?

A

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.

29
Q

How do you calculate aspect ratio?

A

Wing length / wing width.

30
Q

How do you calculate wing loading?

A

Mass / wing area.

31
Q

What are down feathers?

A

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

32
Q

What are semiplumes?

A

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

33
Q

What are filoplumes?

A

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

34
Q

What are bristle feathers?

A

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

35
Q

What are powder down feathers?

A

Continuously growing and are never moulted, disintegrate into powder.

36
Q

What are contours?

A

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

37
Q

What is migration?

A

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

38
Q

What are the dangers of migration?

A
Possible competition changes.
Energy expenditure.
Predation.
Collision.
Hazardous journey, unknown new habitats?
Timing.
Endurance performance.
Navigation.
39
Q

What are the sex chromosomes of birds?

A

ZW for female, WW for male.

40
Q

What does precocial mean?

A

Needs less parental care.

41
Q

What does altricial mean?

A

Needs more parental care.

42
Q

What is polygyny?

A

A male bird breeds with >1 female.

43
Q

What is polyandry?

A

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

44
Q

What is lekking?

A

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