Ornithology Exam 1
mechanical isolation
a barrier to interbreeding between two populations that arises from an incompatibility between the male genitalia of one species and the female genitalia of the other species
habitat isolation
a barrier to interbreeding between two populations that arises from them being found in different habitats, even if otherwise they are in close proximity
subspecies
a distinct population or group of populations within a more widespread species distinguishable from other subspecies on basis of one or more traits (plumage, song, etc.)
drag
a force on a moving object that opposes the direction of travel
hybrid zone
a geographically overlapping area where two species come into contact and hybridize
adaptation
a heritable trait that has evolved by past natural selection to make birds with the trait more successful at survival and reproduction
reproductive isolation
a mating incompatibility that occurs when behavioral, physiological, or genetic barrier prevents successful interbreeding (even where they occur together)
hybrid index
a number derived by calculating the proportion of a hybrid individual's constituent parental species contributions over time
countershading
a pattern of coloration in which a bird is darker on top that below, aiding in loss of detectability
eclipse plumage
a set of dull-colored feathers worn briefly after the breeding season in adult birds (ducks)
sexual selection
a special form of natural selection that involves the differential reproductive success of individuals that arises specifically from competition over mating opportunities (may involve direct competition with conspecifics or competition for mates)
airfoil
a suitably shaped object such as a wing, or bird wing that creates lift when placed in a current of air
clade
a synonym for a monophyletic group
body downs
adult down feathers arising from dedicated follicles
geographic isolation
arises from two populations being separated in space, often with geographic barrier to movement between them
pterylosis
arrangement of feather tract locations unique to clades/taxa
species
basic unit of biological classification. a single ________ includes individuals and populations with very similar traits + history of recently shared ancestors + the ability to interbreed
iridescence
bright, intense, metallic shininess which changes based on angle of perception. this occurs at the micro- or nanostructural level inside barbules
biogeographic realm
broad biogeographic division based on distributional patterns of terrestrial organisms
disruptive coloration
camouflaging coloration type in which patches, streaks or bold patterns help to break up and distract from the overall shape of the bird
pressure drag
caused by the air particles being more compressed on the front-facing surfaces and more spaced out in the back surfaces
crypsis
color that conceals a bird in its habitat
camber
curvature of the wing
pin feathers
developing feathers surrounded by a feather sheath
phylogeny/phylogenetic tree
diagram that depicts the evolutionary relationships connecting a set of organisms
powder downs
down feathers that never molt but disintegrate (at their tips) into a fine powder. aids in waterproofing
natural selection
evolutionary process in which the higher survival and reproduction of individuals with favorite inherited traits causes those traits to increase in the population over time
pterylae
feather tracts (area on birds skin where feathers attach)
rectrices (singular: rectrix)
flight feathers originating from the tail bones to form tail surfaces
remiges (singular: remex)
flight feathers originating from the wing bones to for, the wing surfaces
friction drag
friction of air moving over the wing (caused by the air molecules sticking together)
filoplumes
hair-like feathers, but having a rachis with few or no barbs
monophyletic group/monophyly
in evolutionary terms, any group of organisms that includes the most recent common ancestor of that group and all of its past and present descendants
population
in ornithology, a group of interbreeding birds of the same species that live in the same place at the same time
semiplumes
intermediate between down and contour
behavioral isolation
isolation involving incompatibilities in behavior that prevent the interbreeding of two populations
the biological species concept (BSC)
it places the greatest emphasis on whether or not members of two populations retain the ability to interbreed
slope soaring
lift is derived from air currents that are deflected upward as wind strikes a hill or ridge or from rising eddies created when wind spill over a cliff
thermal soaring
lift is derived from rising air thermals to gain height
dynamic soaring
lift is derived from the gradient in wind speed over the oceans surface. glides down at an angle, then turns and rises abruptly in the wind, using momentum to rise sharply
flap-gliding
long extended-wing gliding after bursts of flapping is energetically beneficial at slow to moderate velocities
melanins
manufactured by cells to produce black and gray (eumelanins) brown, reddish brown and pale yellow (pheamelanin)
structural blue
quasi-ordered distribution or air bubbles in the keratin matrix which scatter only the shortest wavelengths (blues and UV)
adaptive radiation
rapid diversification of a group of species from a common ancestor response to natural selection where species differ in their use of their environment
indirect fitness
the component of an individuals fitness resulting not from their own reproduction, but rather by the aid they give to relatives that then enhances their relatives reproductive success
feather follicle
small epidermis-lined pit in the skin of birds from which the feather grows and remains attached
plumage
the entire feather coat, or to the set of feathers produced by a partial or complete molt
speciation
the evolutionary process by which one ancestor lineage splits into two or more descendant species
direct fitness
the fitness of an individual bird gains through its own production of offspring. this is normally measured via a birds lifetime reproductive success
maximum range speed
the flight speed that maximizes the distance traveled for a given amount of energy
minimum power speed
the flight speed that maximizes time in the air for a given amount of energy
lift
the force acting on a moving airfoil perpendicular to the direction of airflow
reproductive success
the number of viable offspring produced by an individual over their lifetime
basic plumage
the plumage that a bird wears the longest period within the year, between molts to another plumage
alternate plumage
the plumage that results from a partial molt of the basic plumage before breeding
bristles
specialized contour feathers in which the rachis is stiffened and lacks barbs
the phylogenetic species concept (PSC)
species are the smallest group descended from a common ancestor sharing distinguishing features that separate them from other groups
rictal bristles
stiff, hair-like feathers projecting from the base of the beak in some birds
biogeography
study of the geographic of plants and animals
natal downs
temporary downy feathers that fully cover precocial chick at hatching (as compared to altricial chicks) many of these develop into contour or other feather types as the individual ages
glide angle
the angle at which a gliding bird descends through the air
angle of attack
the angle between the main surface of the wing and oncoming airstream
species concept
the precise set of criteria used to decide whether or not two populations are members of the same species
classification
the process by which scientists name organisms and assign them into larger groups based on the evolutionary relatedness
heritability
the proportion of the variation in a trait that is due to underlying genetic variation
fitness
the relative success of an individual--compared with other individuals in their population--in passing along their own genes to later generations
suture zone
the somewhat controversial idea that broad-scale changes in the past habitats have affected they respective species assemblages where multiple hybrid zone converge geographically
vicariance
the subdivision of a species originally large distribution into smaller and separated geographic fragments via some new geographic barrier or fragmentation of the species habitat (glacial advance, continental division, volcanism, radical changes in precipitation)
inclusive fitness (total fitness/absolute fitness)
the sum of direct and indirect fitness
biodiversity
the variety of life forms in a particular place or ecosystem
fault bars
transverse regions on a mature feather with different color and/or texture, indicating that stresses or nutrient deficiencies were at play during feather development
apteria
unfeathered regions or sparsely feathers areas on a bird
psittacofulvoids
vivid pigments found only in parrots
coherent scattering
when air bubbles, melanin, and keratin are arranged in very specific ways to separate and reinforce certain wavelength of light
ecotone
where two biomes, habitats, and avian communities gradate, cause intermediate blends of the pure forms
flap-bounding
wing-flexing after bursts of flapping, saves power at faster flight velocities
pigmentation
often large and complex molecules that when contacted with white light interact it is energy to produce arrays of color. the wavelengths produced are related to the pigment molecules molecular bonds
incoherent scattering
only attributed to white coloration, not blues. caused by the passage of large wavelengths around microscopic air bubbles imbedded in the keratin matrix, but short wavelengths scatter
interference
phenomenon of light wave interaction causing amplitude enhancement (constructive interference) or cancellation (destructive interference)
porphyrins
pigments created by modifying amino acids, producing greens (turacoverdin), pinks, reds, browns, and purples. fluorescence pink under black light
carotenoids
pigments obtained by dietary uptake, including red, orange and yellow
thrust
portion of the force generated by the flapping of wings that propels a bird forward