Exam 2 Flashcards
which hypothesis is a better in terms of models of flight
Ground-Up
How did the evolution of flight provide benefits?
- Flight enhanced hunting and scavenging.
- it enabled many birds to exploit flying insects, an abundant, highly nutritious food resource.
- Flight provides a ready escape from earthbound predators.
- it enables many birds to migrate great distances to exploit different food resources and seasonal breeding areas.
- the arctic tern migrates round-trip between the Arctic to Antarctic each year.
What are the most obvious adaptations for flight
Wings
what are airfoils that illustrate the same principles of aerodynamics as airplane wings
Wings
what are the 2 hypothesis on the evolution of bird flight?
- The “ground-up” hypothesis is based on running birds with primitive wings to snare insects
- the “trees-down” hypothesis has birds through tree-climbing, leaping, parachuting, gliding, and finally powered flight.
what hypothesis fits this:
- theropod running and jumping on the ground
- use outstretched limbs and stabilizers
- fringe allowed for longer jumps
- lead to gliding and then powered flight
Cursorial (running, or ground-up)
what hypothesis fits this:
1. small theropod or theocodont jumping from tree to tree or to ground
2. fringe would slow fall
3. lead to gliding and then powered flight
Arboreal (“Trees Down”)
what kind of dinosaur features does the Archaeopteryx have
-clawed forelimbs
- teeth forelimbs
- teeth in beak
- bony tail
What came first? feathers or flight?
- feathers probably preceded flight and arose for thermoregulatory purposes.
- but, once evolved, provided a superb “preadaptation” for flight
what are the most remarkable of vertebrate adaptations
feathers
what are made if the protein keratin, the same material in reptile scales and mammalian hair and nails
feathers
do most birds have water-proof capabilities
no
may have functioned first as insulation during the evolution of endothermy and were later co-opted as flight equipment
feathers
what lacks hooks on barbules, producing a fluffiness that provides excellent insulation because of the trapped air
downy feathers
what are the stiff ones that contribute to the aerodynamic shapes of the wing and body
contour feathers
what is the stiff, central spine of a feather from which the vanes, if present, extend
Shaft
the broad, usually flat, surfaces that extend from the shaft of contour and flight feathers; the vanes are formed by interlocking barbs.
Vanes
the hollow lower portion of the feather shaft that lacks vanes
calamus
the portion of the feather shaft distal to the calamus; it is often relatively solid and supports the vanes when present
rachis
describes that portion of the vane that is relatively flat and has a defined shape
pennaceous
describes that portion of the vane for which the loose, fluffy barbs are not structured into flat vanes
plumulaceous
the regular, parallel fibers that extend from each side of the rachis to form the feather vane
barbs
the central shaft of a feather barb (from which barbules extend)
ramus
branchlets off the barbs of a feather that hook together with adjacent barbules
barbules
tiny hooks on the barbules that allow them to attach to adjacent barbules, thereby forming the flat surface of a feather vane
barbicels (hooklets)
a stiff protein that forms scales, claws, and feathers
keratin
a small, epidermis-lined pit in the skin from which a feather grows and to which it remains attached
feather follicle
developing feathers that are still surrounded by a feather sheath
pin feathers
the temporary tube-like covering that surrounds a growing feather
sheath
transverse regions on a mature feather with slightly different coloring or texture that correspond to different stressful days of feather growth
Fault bars
feather tracts, the areas of a bird’s skin to which feathers are attached
pterylae
regions of bare or less-feathered skin between the feather tracts
apteria
the pattern and location of the feather tracts on a bird’s skin
pterylosis
are soft, fluffy feathers that typically lack a rachis
down feathers
the down feathers that cover the body of a hatchling bird
natal downs
the condition of chicks that are already well feathered with down when they hatch, with substantial powers of thermoregulation and locomotion, and a considerable degree of independence from the parents for feeding
precocial
the condition of young birds that hatch relatively undeveloped and in many cases naked or with sparse down; such helpless young require complete parental care
altricial
down feathers that lie under the contour feathers in many adult birds
body down
specialized down feathers that grow continuously and disintegrate at their tips to produce a fine powder (herons and pigeons)
powder down
the feathers that make up the exterior surface of a bird, including the wings and tail
contour feathers
a second, smaller feather that grows from the shaft of a larger contour feather
afterfeather
the feathers that form the wings (remiges) and tail (retrices)
flight feathers
flight feathers that originate from the wing bones and form the wing surfaces/airfoil
remiges
flight feathers that originate from the tail bones and form the tail surfaces/airfoil
rectrices
the flight feathers of the outer wing that are attached to the manus (hand)
primaries
the flight feathers of the inner wing that are attached to the ulna
secondaries
the smaller, overlapping feathers that overlie the bases of the flight feathers of the wing and tail
coverts
specialized contour feathers in which the rachis is stiffened and lack barbs
bristles
stiff, hair-like feathers projecting from the base of the beak in some birds
rictal bristles
hair-like feathers having a rachis but few or no barbs
filoplumes
the process of shedding some or all of the feather coat and replacing it with newly grown feathers
molting
refers either to a bird’s entire feather coat, or to the set of feathers produced by a particular partial or complete molt
plumage
the plumage that a bird wears for the longest period within the year, between molts to another plumage
basic plumage
the plumage that results from a partial molt of the basic plumage before breeding
alternate plumage
the set of dull-colored feathers worn briefly after the breeding season in adult birds such as ducks
eclipse plumage
feather maintenance behavior in which a bird tends to its feathers with its bill
preening
parasites such as flies, ticks, lice, and mites that inhabit the exterior of a host’s body
ectoparasites
a gland near the upper base of the tail that secretes oils that a bird distributes across its feathers via preening
uropygial gland
pigments, manufactured within cells, that generally produce a range of earthy colors in various shades of black, brown, gray, reddish brown, and pale yellow
melanins
pigments obtained by birds through their diets that often produce bright yellow, orange, or red colors
carotenoids
patterning or coloration that allows a bird to remain concealed by blending into its environment
crypsis
a type of camouflaging coloration in which patches, streaks, or other bold patterns help break up and distract from the overall shape of the bird
disruptive coloration
a pattern of coloration in which a bird is darker on top than below
countershading
the evolution of reproductive isolation between populations as a result of divergent natural selection in their different locations or environments
ecological speciation
evolutionary radiations that are exceptional in having quickly evolved many species from a common ancestor, in response to natural selection that causes these species to differ from one another in their use of their environment
adaptative radiation
the force acting on a moving airfoil (such as a bird’s wings) perpendicular to the direction of airflow
Lift
the pressure of a flowing fluid, or of movement through a fluid such as air or water. You feel it when the wind blows against your face
Dynamic Pressure
a suitably shaped object- such as an airplane wing or bird wing-that creates lift when placed in a current of flowing air
airfoil
the distance between the tips of the fully extended wings of a living bird
wingspan
unpowered flight, as in birds that are flying without flapping their wings
gliding flight
the curvature of the wings as seen through a cross-section; highly cambered wings are more arched and therefore the upper and lower surfaces are less symmetrical
camber
in a flying bird, the angle between the main surface of the wing and the oncoming airstream
angle of attack
the small “thumb” of a bird’s wing that bears three to five small, asymmetrical flight feathers
alula
a force on a moving object through a fluid (such as air). induced drag comes from accelerating air to produce lift; pressure and friction drag are due to air colliding with moving past the object
drag
the ratio of an object’s length to its width. In birds, it refers to the shape of the wing: birds with higher aspect ratios generally have more pointed wings
aspect ratio
the angle at which a gliding bird descends through the air
glide angle
in a bird, the portion of the force generated by the flapping wings that propels the bird forward
thrust
for birds, the total power required to match the various forms of drag and thereby maintain flight
aerodynamic power
the flight speed that maximizes time in the air for a given amount of energy
minimum power speed
the flight speed that maximizes the distance traveled for a given amount of energy
Maximum range speed
a common flight style among small and medium-sized birds that consists of flapping phases interspersed with flexed-wing bounds or extended-wing glides
intermittent flight
a type of soaring in which a bird derives lift from the air currents that are deflected upward when wind strikes a hill or ridge, or from rising eddies created when wind spills over a cliff
slope soaring
a type of soaring in which birds use rising air thermals–rising columns of warm air–to gain weight
thermal soaring
is a measure of how much load each unit area of wing must carry when a bird is in flight
Wing loading
when applied to flying birds, components of the birds aerodynamic structures that cause the bird to return to an original flight posture when it is disrupted by an outside force (such as wind) without flapping or other active movements
passive stability
the regular, seasonal movement of an individuals away from, and back to, the breeding grounds
migration
the movement of an individual from breeding site to another
dispersal
the tendency to return ti the same location in successive years
philopatry
the non-migratory movements involved in the daily activities of birds
local movements
birds that remain in the same area year round
residents
a pattern in which the timing and distance of migration changes from year to year in response to varying environmental conditions
facultative migration
a pattern in which individuals migrate to the same areas on the same schedule every year
obligate migration
a pattern in which some individuals within a population or species are migrants and others are non-migratory residents
partial migration
refers to birds that move irregularly, rather than in a predictable migration, usually in response to highly variable food resources or other environmental variations
nomadic
the degree to which individuals breeding in a particular region to the same overwintering region
migratory connectivity
the degree to which two breeding populations are connected by dispersal and gene flow
population connectivity
a pattern in which the individuals at the extreme of the breeding distribution migrate farthest, in the process traveling past birds that breed and winter in intermediate
leapfrog migration
seasonal migration up or down mountain slopes
altitudinal migration
refers to seasonal migration in the southern hemisphere, in which birds typically move north in the fall and south in the spring
austral migration
locations where 2 populations of the same species with different migratory orientation meet and potentially interbreed
migratory divides
locations where migrating birds fuel up just before, or in a pause, during migration
staging areas
locations where migrating birds take a short break to rest, eat and drink for maintenance, and/or await favorable migratory conditions
stopover sites
general routes used by large numbers of migrants of many species
flyways
a pattern in which the migrating individuals of a species are spread across a wide area rather than concentrated into narrower flyways.
broad-fronted migration
