9 - Birds

Question 1

Islands

Answer 1

important stopping point for migratory birds

Question 2

Birds timeframe

Answer 2

last on the evolutionary scale when it comes to reptiles

Question 3

Shared characteristics with reptiles

Answer 3

• single occipital condyle
• single ear ossicle
• other skeletal characteristics
• nucleated red blood cells
• nesting behaviour
• endothermy (dino lineages)
• scales on legs

Question 4

Archosaur lineage

Answer 4

• Saurischian lineage called theropods which had feathers

Question 5

Velociraptor

Answer 5

• from saurischian lineage
• bipedal
• feathered
• carnivore with long tale and enlarged sickle-shaped claws on each hind foot used to tackle/disembowel prey

Question 6

Feathers on dinosaurs?

Answer 6

gliders maybe

perhaps thermorégulations

Question 7

Transitional species for flight

Answer 7

found in germany

archaeopteryx

Question 8

Archaeopteryx

Answer 8

• teeth in beaklike jaws
• glider
• transitional species
• reptilian tail and clawed fingers
• imprints of feathers on tail and wings
• well developed clavicles for attachment of wing muscles
• Other skeletal attachments for flight muscles were absent

Question 9

More evidence of flight

Answer 9

alula in wing (for flapping flight) in fossil record

Question 10

Mass extinction when and why

Answer 10

66 mya
Asteroid impact
possibly in combination with increased volcanic activity that created a much different climate
Made opportunity for other groups to irradiate

Question 11

Transition following mass extinction event

Answer 11

• most bird lineages represented by early fossils were extinct
• modern birds diverged from few lineages
• 35 orders
• our thoughts may change as more info is found

Question 12

Class aves 2 superorders

Answer 12

paleognathae

neognathae

Question 13

Paleognathae

Answer 13

large flightless birds, wings with numerous fluffy plumes

1 order

Question 14

Paleognathae 1 order

Answer 14

struthioniformes: ostriches and rheas

Question 15

Superorder neognathae

Answer 15

modern flying bird species

34 orders

Question 16

Modern birds important characteristics

Answer 16

• adaptations for flight
• presence of feathers
• endothermy
• vertebral column modifications and bones lightened by air spaces

Question 17

Adaptations for flight

Answer 17

• Feathers
• Uropygial gland
• Skeleton
• Muscles

Question 18

Feathers function

Answer 18

• flight
• insulation
• courtship
• incubation
• waterproofing

Question 19

2 main types of feathers

Answer 19

pennaceous

plumulaceous

Question 20

Pennaceous feathers

Answer 20

• prominent shaft
• flight feathers = asymmetrical
• contour feathers = symmetrical
• waterproofing, insulation, streamlining

Question 21

Plumulaceous feathers

Answer 21

• rudimentary shaft
• “down”
• insulation/incubation

Question 22

Uropygial gland

Answer 22

• at base of tail

- provides oily secretion for preening which keeps feathers waterproof and supple

Question 23

Anting

Answer 23

• songbirds
• picking up ants and rubbing them over feathers
• formic acid from ants is toxic to feather mites

Question 24

Molting

Answer 24

periodic shedding and replacement of feathers

Question 25

Feather maintenance

Answer 25

uropygial gland, anting, molting

Question 26

Skeleton

Answer 26

• lightweight and strong
• large air spaces and internal strutting
• reduced number of skull bones
• pelvic girdle, vertebral column, ribs strengthened for flight
• fusion of bones in some appendages
• keeled sternum and furcular (wishbone) for flight muscle attachment

Question 27

With front appendages acting as wings:

Answer 27

bill and flexible neck are used in nesting and feeding young

Question 28

Muscles

Answer 28

flight muscles are the largest, strongest muscles

Lots of mitochondria to produce ATP for flight

Question 29

Physics of flight

Answer 29

• wings form airfoil
• anterior wing margin = thicker than posterior
• upper wing surface is convex and lower is concave
• air over wing moves faster than air below ing
• decrease of air pressure on upper wing surface = generates lift
• slotting of feathers at wing tips and alula (little thing that makes the top of win a better shape when wing is down) reduce turbulence

Question 30

Types of flight

Answer 30

• gliding (reduce altitude)
• flapping (most common)
• soaring (less energy)
• hovering (to remain suspended)

Question 31

Hummingbirds

Answer 31

hover
50/80 wingbeats per second
highest known metabolic rates among homeotherms
Feed constantly during the day
Torpor overnight to save energy

Question 32

Homeotherms

Answer 32

an organism that maintains its body temperature at a constant level, usually above that of the environment, by its metabolic activity.

Question 33

torpor

Answer 33

type of deep sleep where an animal lowers its metabolic rate by as much as 95%

Question 34

Bar headed geese

Answer 34

cross himalayas at very high altitudes (6000+ M) during migrations

Question 35

Migration

Answer 35

periodic round trips between breeding and feeding grounds
annual north/south usually
usually winter in tropical regions and northern breeding grounds in spring and summer

Question 36

Timing of migration

Answer 36

• innate (endogenous) clocks or biological rhythms involving the pituitary gland
• environmental cues such as potoperiod “fine tunes” the clock

Question 37

Climate change

Answer 37

influencing timing of migration in many species

Question 38

Navigation during migrations

Answer 38

route-based: landmarks on outward journey used to guide return trip
Location-based: sun compasses, other celestial cues, earth’s magnetic field

Question 39

Status of migrating birds

Answer 39

• in decline
• travel across many habitats so more affected by global environmental issues like habitat loss and insect decline
• scientists think they are “canaries in the coalmine” telling us about state of environment