21. Birds

Question 0

First bird?

Answer 0

Archaeopteryx (ancient wing)

• Jurassic (150 mya)
• Crow-sized

Question 1

Shared characteristics of birds and dinosaur ancestors?

Answer 1

• Bipedal, 3 hind toes
• Carnivorous
• 4-chambered heart
• Similar lungs
• Feathered
• Hollow bones
• Parental care of eggs and juveniles

Question 2

Archaeopteryx

• bird characteristics?
• non bird characteristics?

Answer 2

Bird: feathers + wings

Non-bird: teeth + bony tail

Question 3

Is archaeopteryx ancestor of modern bird?

Answer 3

Not quite. More like shared ancestor.

Question 4

Major characteristics of birds?

Answer 4

• Amniotes
• Endothermic
• 4-chambered heart (completely separate pulmonary and systemic circuits)
• Feathers
• Most fly
• Diverse beaks (due to diverse diets)

Question 5

most unique features of birds?

Answer 5

Feathers (not flying)

Beaks

Question 6

How do bird thermoregulate?

Answer 6

Endotherms - generate their own internal heat through metabolic processes (vs ectotherms)

Question 7

How do endotherms generate heat?

Answer 7

We are less efficient at metabolism - we produce excess heat when we transform food into ATP (or ATP into ADP)

Question 8

Homotherm and Heterotherm?

Answer 8

Other axis - not in opposition to endo/ectotherm. Heterotherm allows their temperature to be modified by outside temperature.

Question 9

Endotherm and maintenance of body temperature in lab? How?

Answer 9

Endotherm: stable.
Metabolic rates indirectly proportional (kind of) to temperature of lab
(exception: too hot, MR increases)

Question 10

Behavioural thermoregulation?

Answer 10

Move between hot and cold microhabitats depending on temperature (goes on rock in the sun, hides under ground, etc.)

Question 11

3 types of thermoregulation

Answer 11

• Behavioural
• Physiological
• Physical

Question 12

Physiological thermoregulation?

Answer 12

Blood flow, sweat, panting, shiver, etc.

Question 13

Physical thermoregulation?

Answer 13

Insulation (fur, feathers, fat, surface area, volume)

Question 14

Physiological regulation, in mammals, is a ….. feddback system in the ….

Answer 14

Negative

Hypothalamus

Question 15

Difference in ears size in rabbits?

Answer 15

Big ears in warm climates to lose more heat

Small ears in cold climates to lose less heat

Question 16

Why do we have fever?

Answer 16

Adaptive to fight infections, who don’t do well in higher temperature - could be an issue to take a fever reducer

Question 17

Issue with birds and respiration?

Answer 17

• Flying + endothermy requires high amounts of oxygen (much more efficient and complex than in mammals)

Question 18

Birds respiratory system - ….. flow of air through lungs

Answer 18

Unidirectional

Question 19

How are birds super efficient in breathing?

Answer 19

Numerous air sacs (8-9) - anterior and posterior

- allows unidirectional air flow

Question 20

Ventilation in birds

Answer 20

Breath 1
1. Air is drawn into posterior air sacs
2. Air is proppelled?
Breath 2
3. Same air is drawn into the anterior air sacs
4. Same is air is propelled out thru nares

Question 21

In birds, it takes ………. for any breath of air to…

Answer 21

• 2 cycles

- Come in and come out

Question 22

4 evolution of flight

Answer 22

1. Insects
2. Pterosaurs
3. Birds
4. Bats

Question 23

Gliding?

Answer 23

Not the same as flying

Snakes, fishes can glide. (planner)

Question 24

Type of evolution in flight?

Answer 24

Convergent - due to common environment, not common ancestor

Question 25

Adaptions for flight?

Answer 25

- hollow bones (lighter) - sternum enlarged and keeled (plus profond, so more surface area to attach large flight muscles) - Feathers

Question 26

Why did feathers evolve?

Answer 26

Not for flight! Probably for insulation (found in theropod dinosaurs)

Question 27

Functions of feathers

Answer 27

- Insultaion - Flight - Sensoring - Lining nests

Question 28

Feathers are all composed of?

Answer 28

Keratin (derived from scale)

Question 29

Scales in bird?

Answer 29

- In feathers | - Scaled skin on their legs

Question 30

How do wings enable flight?

Answer 30

Wings create pattern of air flow below and above the wing that are different - Above wing: lower pressure, higher speed of air - Under: higher pressure, lower speed of air (Particles must move faster to get over bump)

Question 31

More evidence for which theory of evolution of flight?

Answer 31

Ground-up (not tree-down)

Question 32

What would expect evidence for ground up?

Answer 32

- Ancestors more close to those that use to be in the ground (vs. climbing) - Ancestors were running