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