Birds II: Adaptation and Ecology of Birds Flashcards
Describe the structure of a feather
- vane and afterfeather
- pennaceous section and plumaceous section
Describe the vane
- open pennaceous portion
- closed pennaceous portion
- plumulaceous portion
Describe the afterfeather
- aftervane
- aftershaft
Describe the pennaceous section
- barbs
- mechanical strutcure
Describe the plumaceous section
- rachis
- calamus
- insulating
List some feather types:
- wing
- down
- tail
- contour
- semiplume
- bristle
- filoplume
Describe the movement of barbicels in proximal barbules
allows great flexibility as well as integrity
barbicels
distal hooklets
Describe a barb
- proximal barbule
- dorsal flange
- barb ramus
- distal barbule
- base and penulum
- hooklet
- barb ramus
Describe modification of microstructure
typically modifies characteristics associated with thermal properties, waterproofing, aerodynamics
Describe modification of macrostructure
typically modifies structural, or directly functional, properties of feathers
Discuss the variation of secondary feathers
- Laysan Albatross: 40
- Rufous Hummingbird: 6
How many primary feathers are there?
9-11
Describe silent flight in owls
- serrated leading edge
- long, filamentous barbs on trailing edge
- break up larger air vortices over wing into many smaller ones
- reduces air turbulence and sound produced
Woodpeckers
- highly thickened rachis in tail feathers as an additional support
Give some sexually displaying birds
- Marvellous Spatuletail (hummingbird)
- Standard-winged Nightjar
What are the consequences of feathers for bird evolution?
- annual cycle governed by the need to replace feathers during moults
- diversity of shapes, forms, structures and colours that feathers allow as complex colour vision facilitate high rates of speciation
- worldwide dispersal: migration to exploit ephemeral and seasonal habitats worldwide
List some biochrome pigments
- melanins
- carotenoids
- porphyrins
Describe biochrome pigments
some have functions such as melanin and wear
Describe melanins
- black
- brown
- rufous
Describe carotenoids
- from diet
- yellow
- orange
Describe porphyrins
- green
- purple
Describe structural colours
alteration of incident light, e.g. by coherent scattering from nm-scale particles
Describe bird evolution
- 4 types of feather structure have been found in theropod dinosaurs that
are not found in birds - all current types also found
- developmental pathways that control feather development are homologous to those that control scale & hair development
- feathers are the default state in birds
- feather-like structures described from Pterosaurs
Pterosaurs
non-dinosaurian reptiles
Describe the feather development pathway
- expression of Fibroblast growth Factor (FGF) and Sonic hedgehog (Shh)
- development of epidermal placodes into denticles, scales, feathers and hair
Describe the development of an odontode
- wnt then Eda-Edar
- FGF then Shh
- epidermis = enamelled
- dermis = dentine
Describe the development of a Squamate scale
- wnt then Eda-Edar
- FGF then Shh
- epidermis: CBPs and K
Describe the development of a feather
- wnt then Eda-Edar
- FGF then Shh
- epidermis: CBPs and K
Describe the development of a hair
- wnt then Eda-Edar
- FGF then Shh
- epidermis: KAPs and cys-rich K
Beak structure is an exceptionally good guide to
feeding specialization
List some birds with interesting beaks
- flamingo
- shoveler
- avocet
- curlew
- mallard
- African skimmer
- macaw
- wren
- heron
- eagle
- swift
- crossbar
- green woodpecker
Describe ecological partitioning by beak size & shape
- probers go deep to shallow
- surface feeders go small to large
- pickers
- sweepers
Describe adaptive radiation of finches
- species evolving to exploit vacant niches
- niches suggested by variation in beak size and shape
List the different food sources of Darwin’s finches
- fruit
- insects
- cacti
- seeds
Describe the different bills of Darwin’s finches
- parrot-like
- grasping
- probing
- crushing
Delineate Darwin’s finches
- tree finches
- warbler finch
- ground finches
List Darwin’s fruit eating tree finch of a pattor-like bill
Vegetarian tree finch
List Darwin’s insect eating tree finches of grasping bills
- large insectivorous tree finch
- small insectivorous tree finch
List Darwin’s insect eating tree finches of probing bills
- wioodpecker finch
- warbler finch
Describe Darwin’s cactus eating ground finch with a probing bill
Cactus ground finch
Describe Darwin’s seed eating ground finches with crushing bills
- sharp-beaked ground finch
- small ground finch
- medium ground finch
- large ground finch
Describe the genetic roots of Darwin’s finch radiation
- expression patterns of Calmodulin
- over-expression in chick embryos causes elongated bill morphology
Describe long distance movement through flight
a key adaptive feature of birds
Describe bird migratory capacity
- non-stop: 7008-11680 km
- 5.0 to 9.4 days
- 1067-1480 km day-1
- 8-10x higher metabolic rate continuously
- no sleep
Give some migratory birds
- Bar-tailed Godwit
- Arctic Terns
- common cuckoo
- red-back shriked
- thrush nightingale
Describe migration
- response to seasonality: allows exploitation of seasonal variation in productivity
- reflect the evolutionary history, and past effect of climate on a species
Describe Arctic Tern migration
- exploitation of daily solar energy flux
List 3 migration phenomena
- leapfrog migrations
- migratory divides
- ‘non-adaptive’ migratory routes
Describe leapfrog migration
- northern populations winter furthest south
- species breeding range spread progressively northward
- have to migrate further south to find unoccupied wintering areas
- almost all long-distance migrants show similar pattern
Give an example of leapfrog migration
swallow in Europe; N Scandinavian populations winter furthest south in Africa
Describe migratory divide
- population shows split in migration direction
- hypothesis: species existed in two refugia in last glaciation
- current pattern an evolutionary relic of migration patterns evolved during last glaciation
Give an example of migratory divide
- Willow warbler
- one in SW Europe, one in SE Europe
Describe ‘non-adaptive’ migratory routes
species migrating unnecessarily far
Describe non-adaptive wheateater migration
- colonisation of eastern N America from the East
- colonisation of western N America from the West
- 18000km (as opposed to 11000)
Describe Blackcap migration - the basics
- common migrant to the UK and much of Europe
- breeds in summer
- migrates to N Africa in winter
-insectivorous in summer; frugivorous in winter - migratory timing & direction strongly inherited
- rather than migrating SW, migrating NW
