Pre Midterm Flashcards
Where does the term Ornithology come from?
Ornis = birds
Logos = the study of
What are the two unique characteristics that make a bird a bird
Feathers
Presence of a Right aortic arch that carries pure blood from the heart to the body
What is the consensus on the earliest known “bird” fossil?
Archaeopteryx
Are pterosaurs related to birds?
Not at all, wing structure is completely different
How does the bone structure of Archeopteryx differ from reptiles?
Only by the presence of a furcula -wishbone
What are the two current hypothesis on the origin of birds?
The Theocdont and Theropod hypotheses - theropod is more widely accepted - fact check this w textbook
Two hypotheses on the evolution of flight?
Trees down vs ground up
arboreal hypothesis vs cursorial hypothesis
Provide some common points about the morphology of the common bird
High power breast muscle - 1/2 bw
High body temp 41-45 C
high metabolism
high energy food processing system
light weight skeleton - 4.4%
strong light feathers
balanced body plan - gizzard in center of body
What are the highest and lowest numbers of feathers found in birds?
Swan -25 000
Hummingbird - 940
List 6 functions of feathers
- flight
- streamline body
- conserve body heat
- protection / camouflage
- communication
- radiation sheild???? old???
Why might birds moult?
to replace worn feathers
to reduce parasite load
to change plumage to have different messages for mating or camouflage
Do birds usually moult at the same time
Yes - seasonal / cyclical pattern of moulting
How often do birds moult various parts of their body?
flight feathers are yearly
body feathers are 1-2 times a year usually in summer and sometimes again before breeding
some birds add ornamentation pre breeding but dont fully moult
How many different plumages can birds have and how does that actually work?
birds often have a juvenile plumage, a basic plumage and an alternate plumage
- will cycle through plumage depending on season
- some birds have multiple basic and alternate plumages depending on life stage (?)
When do birds usually not moult?
it is very energetically expensive so birds cannot moult while breeding and while migrating
What is the difference between the majority of eastern birds and the majority of western birds when it comes to moulting?
Most eastern birds breed - moult - migrate to wintering grounds - there is better soils and diet diversity in eastern north America so it they have enough energy after breeding to also moult before moving’
Most western birds breed - migrate south w US - moult - move to wintering grounds - need to move after breeding to staging grounds to refuel and have more energy for moulting as there was not enough to do it all in one shot
Why might birds be colored
Color helps protect against feather wear - pigments are strong
- temperature regulation - dark vs light colored feather
- protection - camo - crypticity
- communication between / among sexes
— may show age or quality of bird towards a mate
— may fool other birds
What are the two things that can cause feathers to be colored?
Biochrome pigment
– melanin
– carotenoids
– porphyrins
Structure
– often blue colors - in the blue jay its transpartent polyhedral cells that scatter blue when reflecting light
– iridescence
How do we get each color on birds?
Melanin - black grey brown
Carotenoids - yellow orange red - obtained from diet . environment (flamingos+ shrimp)
Porphyrins - brown magenta green
Structure based - blue
What are fault bars?
lighter colored feathers in a band across all the tail feathers - indicative of poor feather growth
poor feather growth may be due to lack of nutrients or stress
feathers are brittle and semi transparent
Can there be more than one color on a single feather?
yes
Why might some primarily white birds have black feathers on the tips of their wings
black feathers absorb more heat which produces a slight amount of additional lift
- melanin may also protect from wear slightly
Talk about the range of color vision in birds
birds can see in infared and UV
many species where we thing males look like females are actually dimorphic in UV light
Avian range is 300-700nm
- some gapes are UV - so parents can spot chicks from further away
Do birds sweat?
no
What is the integument?
skin - thin and lightweight - no sweat glands
What is the single sebaceous gland on birds?
The uropygial gland
- aka the preening gland
- provides oil in many species for cleaning and waterproofing
Skeletal modifications in birds
reduction in bone number and bone weight (via air spaces)
-fused bones
- sternum/keel
- adapted rib cage
- pectoral girdle
Specifics of the bird skull?
no teeth
gizzard “chews” food
- two layers of thin bone - connected by columns of bone
- skull pneumaticization - formation of air pockets in the skull for flight purposes
Define pneumaticized - what does that mean in this context
air filled - criss crossed air filled pockets for purpose of making body lighter
What are the fused bones in modern birds compared to archaeopteryx?
Fused
- Skull
- hands
- thoracic vertebrae
- pelvic bone - synsacrum
- fewer tail vertebrae - pygostyle
Three components of the pectoral girdle - examples of fusion in the pectoral girdle
furcula - wishbone
coracoid
scapula
what is relevant about cervical vertebrae?
- example of non fused bones - actually have more neck bones for dynamic movement - fishing / hunting etc
- very flexible - flexibility requires more bones
Avian digestion main points
structure of digestive track can be specialized to different things and change between seasons
What is hyperphagia?
some migratory birds will absorb their digestive systems before long migration trips
Bird digestive track key organs
Esophagus
Crop - stores food while gizzard is busy
Glandular stomach - secretes digestive enzymes
Gizzard - grind food and replaces teeth to conserve center of gravity
Small / large intestine
What respiratory organ are birds missing?
Birds have no diaphragm
What is the syrinx
pair of membranes between the trachea and the bronchi
- air moving across the syrinx causes vibrations and sound production
- muscles regulate tension and tone
- allows them to effectively breathe and sing at the same time
Explain the parts of the avian heart
- 4 chambered - left side pumps to body, right side pumps to lungs - the aorta branches right
- relatively large heart compared to BW
- high bpm - up to 570 in robins - compared to ~ 80 in humans
What are the two portal systems in birds
renal portal system - valve to control wether blood passes through kidneys or not
hepatic portal system - controls flow to liver
What is unique about avian red blood cells?
avian red blood cells are nucleated whereas mammal red blood cells do not have nuclei
Why might bird RBCs be nucleated? Best theories?
high metabolism - nucleated can hold more O2
- more efficiency with high output of O2
What is the white stuff in bird poop?
Urates
Difference between avians and mammals in dealing with nitrogenous wastes?
Mammals dilute waste with water and excrete it as urea
but water is heavy so birds excrete it as uric acid which is less toxic and more nitrogen is excreted per volume of water
How does excretion work with birds?
Kidneys excrete uric acid in urine to the cloaca where it is mixed with feces from the digestive system
Why is being water efficient with waste important for egg laying species like birds?
in mammals all the watery waste can be removed via the mothers digestive system but for birds the waste is trapped in the egg with the bird so it is important to be efficient
Two sections of the avian nervous system and what are the parts of each?
Central nervous system
- brain
- spinal cord
Peripheral nervous system
- glands
- muscles
- heart
- visceral organs
- sense organs
Avian hearing - 3 points
- most advanced in owls - can echolocate
- more hairs in inner ear allows discrimination of temporal sounds 10X humans
- barn owl uses satellite dish face to concentrate sound and has ears set in asymmetrical position to aid location of sounds
- overall range of frequencies birds can hear is less than humans
birds have the ______ resting rates of metabolism among vertebrates
highest
are birds endothermic or exothermic?
endothermic with a relatively high body temperature
first line of defense to reduce heat loss?
dont want to spend more energy / increase bmr
- will puff up first before shivering which increases heat
what is evaporative heat loss
pairs veins with arteries so that heat loss is minimized
do birds pant or sweat
panting birds cant sweat
why do small birds eat more than large bird
because they need to spend more energy to stay warm?
humming birds enter _____ to avoid having to feed in the night?
torpor - state of super low metabolism where everything is shut down - the step before hibernation
What are some functions of the primaries and secondaries in powered flight?
primaries is for driving the powered flight
secondaries are for controlling lift
What is the competitive exclusion principal?
species with identical ecologies cannot live in the same place at the same time - one will be a better competitor
How can a niche be differentiated?
range, habitat, - microhabitat
- food / foraging behavior
- time of day for foraging
What is hutchinsons ratio?
Birds with virtually identical ecology and morphology can coexist if different sizes - usually 1.3x longer and 2x heavier
Main mechanism for geographic isolation in north america
generally followed glacial trends
Explain variables in hybrid zones
can originate allopatrically or peripatrically
- hybrid fitness extent
- low fitness , short lived
- equal fitness wide, longer lived
- higher fitness stable, new species
Define parapatric speciation
next to fatherland
- speciation that occurs between neighboring populations
- no geographic isolation
Define allopatric speciation
new species forming as a result of geographic isolation
Define peripatric speciation
new species forming from a small outgroup nearby to a larger parent populations - island population with a larger family on the mainland
Define sympatric speciation
speciation occurs despite identical ranges
- no geographic isolation
- speciation within a population
define community? 2 factors that affect communities
group of coexisting species in a given location
Historical - event promoting allopatric speciation - natural disaster
Ecological - greater diversity of ecological factors may provide more available niches than others - competitive exclusion principal
Define phylogenetics
subfield of systematics focuses specifically on reconstructing the evolutionary relationships among organisms using genetic techniques
What was a problem with early dna sequence studies
often asked questions at the species level with only small sets of bases to compare - did not account for individual or population differences
Why do modern sequencing method sequence entire genomes?
because it is the best way to get the most comprehensive dataset
- birds have relatively small genomes
What is the advantage of a phylogenetic species concept compared to a biological species concept
biological species concept has problems with being arbitrary or untestable in the field - cannot tell degree of difference
- tends to lump
- fewer species
- phylogenetic species concept is quantitative
- may have too many species
Are all loci created equally?
no - sometimes a change at a single base pair is enough to change phenotype - great and white herons
- sometimes many loci changes will not lead to much of a phenotypic change
Define taxonomy
classification of organisms based on relationships
- kingdom, phylum, class order genus species subspecies
(double check)
suffixes for order family and subfamily
order - iformes
family -idea
subfamily -inae
Traditional approach to bird systematics
done entirely on comparative anatomy
- based largely on phylogeny
- had to develop an evolutinary scenario to arrange phylogeny
- subjective
Phenetics / numerical taxonomy approach
- measure wide number of features
- still on comparative anatomy
- same trait across as many groups as you can get to calculate a similarity index
- uses statistics for similarity to present relationships
Cladistics approact to bird systematics
- select set of similar species for an ingroup and very different species for an outgroup
- distinguish primitive traits from derived traits
- do this as hypothesis testing and cycle through
Things that make a great trait for systematic - phylogenetic analysis
- must be genetically controlled and not too environmentally plastic
- variable but not too variable - bill shape works on mainland but not islands (bc of founder effects)
- behavioural and ecological traits work
- morphology and physiology are good
- protein electrophoresis used to work
- molecular biology
Why might birds have a strong spatial memory and be good at counting?
To know where and how many cache stores they have
what is monocular vs binocular vision? advantages of each?
one eye on either side of head vs both eyes forward - monocular vision has higher field of view but less depth perception
What is the tip vortex?
turbulence at wingtips, causes drag
influcend by wing size and shape, alula
