major physiological features that birds share with other related vertebrates, and explain novel, derived features that set them apart.
features shared with reptiles
scales, single middle ear bone, oviparity, egg struture
derived features
flow through lungs, feathers, horny bill
basic timeline of evolution within Class Aves, from the first birds to modern, extant taxa
evolved in late jurassic
diversification event in cretaceous
mass extinction event in late cretaceous
ancestors of all living birds lived then diversified into major groups of birds alive today
Thecodont theory
birds and dino evolved separately from the common ancestor thecodonts
feathers evolved for flight
gliding flight theory
gliding origins more likely
small tree dwelling theocodonts found
no supporting fossil evidence
247 mya dinosaurs evolved from thecodonts birds evolved between around 150 mya
Theropod theory
Dinos diversified into theropods which diversified into birds
birds evolved features for thermoregulation
ground up flight
ground up theories difficult to argue
in support
bone morphology similarities
feathers present
Sinosauropteryx = tiny theropod with feathers
Define the two major species concepts used by ornithologists, and explain and contrast the ways they are used to describe evolutionary relationships, including the type of evidence used for each concept.
biological- traditional view, based on reproductive isolation, interbreeding populations cant breed with others, problem - -hybridization
Phylogenetic- putting together trees based on shared or derived characters, problem what do you choose ( morphological or molecular)
List the major subgroupings of modern bird taxonomy
Palaeognathae - flightless birds
Neognathaes- flying birds
Explain, with examples, the relevance of taxonomy and systematics to management and conservation of birds
for legeslation and policys we need to be able to discribe the species we want to help and its range, which helps us create boundaries between species, by recognizing sub species = can make individual management plan. subspecies vary in distribution, morphology, and behavior ex canada goose 12 subspecies
Identify the basic feather types and describe their function(s).
locomotion, thermoregulation, communication, protection
A) filoplumes lie amidst the contour to provide a sensory function; B) bristles occur around the nostrils and eyes, providing protection; c) powder down occurs on the breast of some birds, disintegrating to create a powder like substance that aids in feather maintenance; D) contour feathers are those that give a bird its form, as they are what are readily visible, and they provide all the aforementioned functions; E) down insulates and camouflages young of many species; F) semiplumes function in display.
Characterize the sequence of molts and plumages in a typical bird
Natal down > (Pre juvenal Molt) > Juvenal Plumage > (Basic Molt) > Definitive Basic Plumage > (Basic Molt) > Definitive alternate Plumage
Describe how color is produced by various pigments and structural features of feathers.
Color is produced via two mechanisms: 1) pigmentation; and 2) structure. What you see (and perceive) is that wavelength reflected from the feather and detected by the cones of your retina, with subsequent transmission via the optic nerve to the visual centers of our brain.
Structural colors, such as iridescences of the gorget of a male hummingbird, or the blues of a Mountain Bluebird, are created by the angle of incident light striking structures within the feather. The following website explores the colors that are characteristic of bird feathers. pigmentation is color in molecules
Identify the 4 forces that act to influence flight
• Gravity – weight of the bird pulling
down
• Lift – generated by secondaries & tail, upward pressure force countering gravity
• Drag – resistance to forward motion
• Thrust – provided by primaries,forward force countering the slowing influence of forces of turbulence and frictions
Explain how lift is generated.
Cambered shape = airfoil
• Unequal distances of air traveling (static pressure is greater below creating lift)
over dorsal & ventral surfaces
• Static pressure = atmospheric
• Dynamic pressure = kinetic energy of
wind
the air flows faster on top of the wing than under the wing. Air flowing faster on top causes the bird to be pulled upward, and the air flowing slower underneath the wing, cause it to be pushed upward
Distinguish between the various types of flight.
Gliding- controlled falling traving some horizontal distance while also traveling some vertical distance. Slowing coming to the ground.
Soaring- A way to glide more effectively, where you don't come to the ground, taking advantage of upward movements of wair, riding air to counteract gravity
flapping-during the downbeat, the wingtips move forward and down and make a loop at the bottom of the downstroke. During the upbeat, the windtips move up and backwards. In the downstroke, the pressure is greater below the wing than above, so it causes lift. As the bird's speed increases the air flowing over the airfoil causes even more lift.
Explain in detail how the muscles of the breast power flapping flight.
Pectoral muscles contract; they bring each wing down creating thrust and lift. In response the supracoracoideus that is connected by a tendon on top of the hummus works as a pulley to lift the wing everytim the muscle contracts
Define migration and describe migratory behavior (e.g., zugunruhe, hyperphagia).
migration= predictable round trip movements
These are migratory behaviors
Zugunruhe = e experience of migratory restlessness
more active, restlessness, wanting to move in direction of migration
Hyperphagia = The dramatic increase in the amount of food that birds consume as they prepare to migrate;
changes in behavior, physiology, anatomy
Explain how birds use a variety of environmental cues to orient and navigate "home."
when birds grow up they start gaining a mapsense, or sense of the environment. look and remember environmental cues. Also use orientation(ability to more in a given compass direction) use navigation = directed movement, locate its position on a map, and determine the correct direction (Pigeons using freeways)
Describe evidence that migratory behavior is genetically pre-programmed in birds.
1. juveniles migrate alone and sometimes on a different path than adult
2. cross-fostering experiment showed it could go either way
3. predictable changes in physiology and behavior
4. interspecific differences= Species differ in the
duration and intensity
of migratory
restlessness
Give specific examples of the value of incorporating knowledge of migration into conservation
Many species migrate, Conservationists can help threatened bird populations by protecting habitat along major migratory flyways
Detail the products of the excretory system
paired metanephric kidneys filter waste from the blood and concentrate it as uric acid. Under conditions of abundant water supply, Anna's Hummingbirds have been shown to excrete ammonia, but this is rare in birds
Explain how a salt gland facilitates excretion of salt from species occupying marine environs.
• Counter-current system
• Active transport of salt
across thin walls of capillary
network
• Salt solution collected in
lumen
• Dripped or forcibly ejected
from the nostril
Provide a detailed description of the mechanisms by which a bird breathes
Birds have evolved to be an outstanding mechanism of efficiency. Instead of having two large lungs that contain the air sacs, birds have relatively small lungs which are surrounded by nine air sacs.
-expand ribcage
-inhale - air leaves lung
-exhale- air enters lung
air sacs
don't play direct role in gas exchange
serve as bellows to store extra air
Allows a continuous stream of air to pass through the lungs in a one way flow
Describe features of the circulatory system that effect efficient transfer of oxygen and nutrients to the tissues.
delivers O2 rapidly
large 4 chambered heart
high blood pressure
large stroke volume
separate pulmonary and systemic circulation
Identify each of the segments of the digestive system and describe its function
The bill is the main tool by which birds obtain food
crop is the esophagus which function is for food store for later digestion
foregut- start of digestion, chemical digestion
Gizzard grinding and physical digestion
Intestines- absorb nutrient and water
Ceca- bacterial digestion
Cloaca- opening for digestive, excretory and reproductive system
Explain interspecific variation in diet as it relates to the morphology of the bill and anatomy of the gut.
great variation in diet their bill represents the way they interact with food and the environment depends on diet. Similar variation exists across species in their digestive system
Explain some of the reasons why herbivory likely is rare in birds
Hard to digest
low energy gain
longer to forage and digest (more weight)