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Beak Shape and size: Evolution - Coggle Diagram
Beak Shape and size: Evolution
Feeding ecology
depends on organism
studies done
waterfowl
ducks
geese
pursuit divers
screamers
Article
Feeding ecology is the primary driver of beak shape: Olsen
hypothesis
if feeding ecology is primary driver of beak shape
then explanation of variation of beaks should come
Result
beak shape correlates heavily with diet
Goose-like beak
associated with
Increase consumption of leaves & roots
Decreased consumption of invertebrates
Diver-like beak
associated with
increased vertebrate consumption
decreased invertebrate consumption
no evidence found
feeding ecology effecting size
diet and beak size
diet and body size
beak shape and size
Darwins reseach
helped determine
feeding on particular foods
influences beak shape/size
examples of adaptation
finches
normally seed-eating
Article
Feeding ecology is the primary driver of beak shape: Olsen
Article
The evolutionary relationship among beak shape, mechanical advantage, and feeding ecology in modern birds
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Author: Navalon
beak function
preening
vocal modulation
thermoregulation
water balance
used geometric morphometrics
to quantify beak shape variation
in sample of birds
partition sources of beak shape evolutionary variance
test strength and pattern of correlation
RESULTS
PGLS regression of beak shape
as a function dietary prefer.
weak correlation
thin straight beaks
associated with
higher % invertebrate consumption
deeper curved beaks
associated with
consumption of more mechanically demanding food
EX: vertebrates and seeds
Slightly curved beaks
associated with
highly piscivorous taxa
adaption to dietary composition
not fine-tuned
broad macroevolutionary
more complex but weak overall covariation
beak shape and diet
Relationship between beak shape and dietary pref.
different within UBF groups
beak shape and feeding ecology
broad macroevolutionary scale
more complex
Definition
understanding of
habitat preferences
prey selection
predation
EVOLUTION
competition
energy transfer between ecosystems
Evolutionary trajectories
ancestors of waterfowl
duck-like beak
slowly transitioned
pursuit diver beak
goose-like beak
vocal performance
Article
larger beaks
slower pace
narrow beaks
used for
nectarivory
hawking
elongated beaks
higher frequency
Evolution of a multifunctional trait: Friedman
size and shape
EX: song birds
species studied
honeyeaters
possible study
different muscles used to move beak
could be consequence from
thermoregulation
foraging ecology
Article: Correlated evolution of beak morphology and song
structure/morphology of beak
places constraints on range of signal output
Beaks opened more widely
production of higher frequencies
Beaks opened less widely
production of low frequencies
performance of songs
depends on
motor constraint,
Hypothesis #1
beak size may influence
quality of performance of ind.
Extensive research: Darwins Finches
Smaller radiation
species with larger beaks
higher force application
Jaw musculature
Songbirds
extensive research using this species
question: conclusions applied only to songbird
are able to learn songs
vocal evolution hard to track
New study
Species
Woodcreepers
Tracheophone suboscine passerines
Song learning
limited/ absent
simple/stereotypical songs
beak gape modulation questionable
open and close beak quickly
beaks
have diversity
small and straight
long and down curved
beak length
correlates with
song frequency
EX:
Long beaks= lower pitched songs
Results
positive relationship
beak size & vocal deviation
large beaks
songs with high vocal deviation
low performance
small beaks
songs with low vocal deviation
high performance
conclude
vocal performance, evolved close with beak size
Beak width and depth
weak relationship
vocal deviation
strong relationship
beak length and vocal deviation
Thermoregulation
Article
Smaller Beaks for Colder Winters
Results
Maximum summer temp.
observation area
large beak size
hot summer & harsh winter
very mild winters
little correlation to beak size
not a big effect on beak size
Consistent correlation
winter temp & beak size
low winter min temp
beaks
low surface ares
Meliphagidae & Maluridae
shorter length
Meliphagidae & Maluridae
smaller width
Acanthizidae
consistent across clades
beak size
mainly correlated
winter temps in models
MAIN QUESTION
Beak size determination?
dissipating heat in the summer?
retaining heat in winter?
changes in beak size
possible explained by beak role in thermoregulation
winter heat retention
thermoregulatory structures
beaks function as radiators
shed heat by convection
problem for heat retention
Species
Australian honeyeaters & allies
158 species
varying climates
drives morphological evolution
Allens Rule
studied on limb length
new study
beak size
definition
ability to keep body temp at a certain level
especially when being tested by environmental temps.
Extreme cold
extreme heat
Feeding ecology/behaviors
related to
shape
greater effect on
foraging ecology
size
greater effect on
climate
possible
climate
morphology
Article
Evolution of a multifunctional trait: Friedman
foraging
for nectar
curved beaks
insects,
straight beaks
on / near ground
beaks tapered toward end
in canopy
beaks taper throughout
influenced
beak size
beak shape
biggest effect
more articles
requested through ILL
General info: Beaks
multifunctional trait
different uses
preening
nest building
song/vocal preformance
understanding uses
insight on future evolution
other function
visual
acoustic signaling
evolution of beak morphology
shaped by multiple functions
Article
Evolution of multifunctional trait: Friedman
Darwins finches
most research done
provided new testing
understanding to different hypothesis
