Birds

Question 1

Where is it believed birds evolved from?

Answer 1

Theropod dinosaurs

Question 2

In which era were birds being assembled?

Answer 2

Early Cretaceous

Question 3

What is the Archaeopteryx?

Answer 3

Transitional organism between feathered dinosaurs and modern birds, emerged in the late Jurrasic, between 148-155 million years ago

Question 4

Name the Archaeopteryx’s bird-like features

Answer 4

1) Long spindly legs
2) Long neck
3) Small head and large eyes
4) Pubic bone rotated
5) Fused clavicles
6) Outwards arm rotation
7) Modern flight/contour feathers

Question 5

Name the Archaeopteryx’s reptile-like features

Answer 5

1) Clawed hands
2) Long thin and bony tail
3) Teeth
4) Small sternum
5) Solid bone structure

Question 6

Describe the Confuciusornithidae

Answer 6

Moe bird-like than Archeopteryx, it had hollow bones, a toothless beak, clawed wings and a shortened tail

Question 7

What are vestigial wing claws?

Answer 7

Small bony protrusions on the wings that aid in gripping branches. They still exist today in spur-winged plovers and hoatzin chicks

Question 8

What is the name given to ‘early true birds’? And what did they have that modern birds don’t?

Answer 8

Euornithes. Teeth

Question 9

Moas and Elephant birds belong to which super-order?

Answer 9

Paleognathae

Question 10

Which super-order is most speciose?

Answer 10

Neoaves

Question 11

To which super order do ducks, geese and swans belong?

Answer 11

Galloanserae

Question 12

Name the 5 feather-types and what they are for

Answer 12

Filoplume - displays
Flight - flying
Bristle - sensing
Down - insulation
Semiplume

Question 13

Describe the structure of a feather

Answer 13

The calamus (tip) extends upwards and fanning off both sides is a vane composed of barbs and barbules. The rachis gives the feather mechanical support across its entire length.

Question 14

Feathers take a lot of effort to maintain. Name the activities performed by bird species in order to maintain their feathers.

Answer 14

1) Preening with oil from a preen gland
2) Bathing in water
3) Dust bathing
4) Anting

Question 15

What else can feathers do?

Answer 15

They can provide camouflage through cypsis and also visual and acoustic displays in birds of paradise.

Question 16

How do birds maintain their body temperatures?

Answer 16

1) Complete homiothermy
2) Strategic hypothermia
3) Torpor
4) Hibernation

Question 17

Why is it beneficial for an organism to fly?

Answer 17

Avoid predators
Hunt
Reach safe nesting sites
Extends home-range size
Display flights

Question 18

How do wings enable flight?

Answer 18

They have an aerofoil shape, meaning air takes longer to travel over the wing rather than under, which generates lift. Increasing the angle of attack increases lift but reduces forward momentum. The downstroke increases pressure on the wing underside, generating more lift during a wing flap. The wing is partially folded and flexed on the upstroke to reduce drag, although hummingbirds achieve lift on both the upstroke and downstroke.

Question 19

Describe one evolution of flight model

Answer 19

Trees-down model; (gliding) swooping down to catch prey from a vantage point, it could explain why Archaeopteryx was poorly adapted for flapping but had asymmetrical aerodynamic feathers. However foot morphology suggests proto-birds did not climb trees.

OR

Ground-up model; It takes a swan to run to 12km/h before it can take off, but protobirds couldn’t run that fast. Maybe they used their wings for wing-assisted incline running or wing assisted water walking.

Question 20

What is an irruptive migration?

Answer 20

Migration that isn’t tied to seasons (although there is correlation)

Question 21

What is a fovea and why do some bird species have more than one?

Answer 21

An area of clear visual acuity. 54% of birds of prey have two fovea for advanced sidewards viewing, and greater field of acuity

Question 22

Why do birds retinas contain many photoreceptor cells?

Answer 22

They contain folded membranes layered with visual pigments to trap light from a narrow angle

Question 23

How to birds have better resolution than us?

Answer 23

Larger eyes (image spread over more photoreceptors)
Tighter packing of the photoreceptors
Increasing cone:rod ratio

Question 24

How do birds have better sensitivity than us?

Answer 24

Bigger pupils

Increasing cone:rod ratio